Foreword those with a professional interest in water. With ... · made or natural, are not...

Located on a map, Tucson is seen as a geographic area with specificboundaries. Those of us who actually live in Tucson know the set-ting more intimately, beyond the one-dimensional view on the map.

We know its mountain ranges, rivers and vegetation, and we experienceits distinct sense of distance and space. And there is more. We knowTucson as a human setting or, in other words, a home to 750,000 people.The way we live our lives, our beliefs, activities and interests help explainthe values that also make Tucson unique.

The human way of life and the physical setting, whether human-made or natural, are not independent of each other; instead they inter-act. Nowhere is this more evident than in the need for water to sustain arich and complex urban life. Water is the beginning of such a life, butwater also can be the end of it. If a sustainable source of water is notavailable, a community obviously is in dire straits.

Tucson now relies predominantly on groundwater, considered “oldwater” because of its storage underground for hundreds and even thou-sands of years. Most people realize the city cannot continue to pumpthis mostly nonrenewable source of water and that other sources of watermust be utilized. This raises the important question: What must Tucsondo to ensure a sustainable water supply?

Answering this complex question requires a consideration of thephysical or environmental conditions of this desert city. Also to be con-sidered are the social, cultural and economic values that prevail in thearea. Science and technology are tools to be used. Not to be overlookedare the different sets of values and beliefs that also guide and motivatehuman actions. The perspective must consider the past, present and fu-ture. Obviously there are no simple solutions.

The following study charts a course among the many issues to beconsidered when attempting to plan a sustainable water future for Tuc-son. A guiding premise of the study is that identifying such a course isthe responsibility of everyone in the community, not just politicians and

those with a professional interest in water. With so much at stake,identifying sustainable water supplies might be thought of as a quest, ofconcern to literally everyone who uses water.

To do justice to the topic, the study provides a broad focus, examin-ing many and varied issues that relate in some way to ensuring futureTucson water supplies, including historic, hydrologic, political, eco-nomic and technological concerns. No direct solutions are recom-mended, but by offering a wealth of information the study intends todemonstrate the complexity of the situation. By promoting an under-standing of the various issues, the study will help Tucsonans make in-formed decisions about their future water supplies.

No other issue better demonstrates the complexity involved in decid-ing water policy than the Central Arizona Project. To use its water ornot to use it and under what conditions and circumstances are consider-ations that have divided the community and have launched CAP as to-day’s premier Tucson water issue. The first question is whether CAP,which promises a renewable supply of Colorado River water, should bepart of Tucson’s sustainable water supplies. In the absence of other via-ble alternatives, use of CAP water becomes a necessity for Tucson’s sur-vival. Other questions about CAP water remain. How should it betreated and how should it be distributed? Is it feasible to continue rely-ing exclusively on groundwater for drinking water, with CAP water usedonly to recharge the aquifer? Is some combination of CAP water,groundwater and effluent viable for Tucson?

What are the implications of Tucson’s water supply to the cultureand character of the city, now and in the distant future?

This study addresses all of these questions, but it does not proposedefinitive answers. Ultimately the people must decide social policy. Ourgoal is to give everyone an opportunity to make well-informed decisions.

Foreword

Peter Likins, PresidentThe University of Arizona

Acknowledgments

The Water Resources Research Center thanks the Office of the President of the University of Arizona for its generous fi-nancial support of this study. This publication is one part of the University of Arizona’s Water Sustainability Project.

Many thanks to the following UA faculty and staff who reviewed all or portions of this report and whose expertise wasinvaluable: Cornelius Steelink, Chemistry Department; Robert Glennon, College of Law; Marv Waterstone, Department ofGeography and Regional Development; Gerald Matlock, International Agriculture; Victor Baker, Nathan Buras, JimWashburne, Gray Wilson, Hydrology and Water Resources Department; Janick Artiola, Jim Riley, Arthur Warrick, PeterWierenga, Soil Water and Environmental Science Department; Sol Resnick, Val Little, Water Resources Research Center.

A project of this sort builds an awareness of the incredibly varied talents, interests and abilities of members of the Tuc-son water community, whether employed by government or the private sector, or whose interest in water is not directly re-lated to job or profession. Gratitude is due to many in the water community who provided advice, encouragement andinformation.

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PREFACE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .v

CHAPTER 1 THE SETTING. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1Climatic Influences. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2

CHAPTER 2 LOOKING TO THE PASTTO UNDERSTAND THE FUTURE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

The Search for Water. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .519th Century Supplies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6Early 20th Century Expansion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7Controversy of 1975-76. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9Central Arizona Project. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11Today's Water Providers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13Agricultural Water Use. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14Ongoing Search for Water Quality. . . . . . . . . . . . . . . . . . . . . . .14Other Water Quality Problems. . . . . . . . . . . . . . . . . . . . . . . . . . . .16

CHAPTER 3 IN SEARCH OF ADEQUATE WATER SUPPLIES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17

Tucson's Water Supplies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17Non-Renewable Supplies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17Impacts of Excessive Groundwater Pumping. . . . . . . . . . 19Renewable Supplies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22Augmenting the Water Supply — Recharge. . . . . . . . . . .25Other Strategies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30Strategies for Individuals. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32

CHAPTER 4 COPING WITH FLOODWATER. . . . . . . . . . . . . .35Flooding, Then and Now. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35Coping with Flood Hazards. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36

Capturing River Flow. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40Water Quality. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41

CHAPTER 5 THE MANY USES OF WATER. . . . . . . . . . . . . . .43Water Uses. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43Municipal Water Use. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43Types of Municipal Water Use. . . . . . . . . . . . . . . . . . . . . . . . . . . .44Conservation Rules. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46Use of Renewable Supplies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46Residential Water Use. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .49Higher Water Use Trends. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .53Water Rates and Conservation. . . . . . . . . . . . . . . . . . . . . . . . . . . .53Contrary View. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55Agricultural Water Use. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55Industrial Water Use. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .59Riparian Areas and Wildlife Habitat. . . . . . . . . . . . . . . . . . . . .61

CHAPTER 6 ENSURING SAFE DRINKING WATER. . . . 65Tucson Water Quality. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .65Groundwater Pollution. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .65Wastewater Treatment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .68Central Treatment vs. Individual Systems. . . . . . . . . . . . . .70Health Risks of Various Pollutants. . . . . . . . . . . . . . . . . . . . . . .70Removing Disease-Causing Microbes. . . . . . . . . . . . . . . . . . .72Reducing Corrosivity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .75Reducing Toxic Substances. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .77Reducing Hardness and Salinity. . . . . . . . . . . . . . . . . . . . . . . . . .77Improving Taste, Odor and Appearance. . . . . . . . . . . . . . . .80Quality of CAP Water. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .81Water Treatment Cost. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .83Issues to Consider. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .84

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CHAPTER 7 ROLES OF CITIZENS AND GOVERNMENT IN WATER POLICY. . . . . . . . . . . . . . . . . . . . . . . . . .85

The Roles of Citizens. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .85The Roles of Government. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .86Water Quality Regulations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .88Treatment Plant Funding. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .90Groundwater Quality Laws. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .90Hazardous Wastes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .91Safe Drinking Water Act. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .91Water Supply Regulations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .92Groundwater Management Act. . . . . . . . . . . . . . . . . . . . . . . . . . . .92Indian Water Rights. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .96CAP and the Colorado River. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .98Central Arizona Water Conservation District. . . . . . . . . 99Programs to Promote Recharge. . . . . . . . . . . . . . . . . . . . . . . . . . .99Lakes and Pools. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .101Water Transfers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .101Federal Environmental Laws. . . . . . . . . . . . . . . . . . . . . . . . . . . .101Regulation of Water Companies. . . . . . . . . . . . . . . . . . . . . . . .103Regional Water Quality Planning. . . . . . . . . . . . . . . . . . . . . . .103Floodplain Management. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .104Powers of Counties and Cities. . . . . . . . . . . . . . . . . . . . . . . . . . .104

Managing Water and Wastewater. . . . . . . . . . . . . . . . . . . . . .105Coordinating Water Management. . . . . . . . . . . . . . . . . . . . . .106Basin-Wide Water Management. . . . . . . . . . . . . . . . . . . . . . . .107Tucson Water Operational Options. . . . . . . . . . . . . . . . . . . .108Enfranchising Non-Residents. . . . . . . . . . . . . . . . . . . . . . . . . . . .108

AFTERWORD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .111Balancing the Budget. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .112To Sustain or Not to Sustain. . . . . . . . . . . . . . . . . . . . . . . . . . . . .112Water Budget Scenarios. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .114

APPENDIX A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .117

APPENDIX B. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .123

APPENDIX C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .141

LIST OF FIGURES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .147

LIST OF TABLES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .149

INDEX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .151

iv

v

Tucsonans face important decisions in thecoming months and years that will affectthe future of their community. At issue is

Tucson’s water supply, the true lifeblood of thearea. A topic of vital importance and one thataffects every citizen, Tucson’s water supply haslong been the focus of controversy. Debatesabout water issues have caused divisiveness andstrife within the community. A major and on-going source of controversy has been the city’seffort to introduce Central Arizona Project(CAP) water into the city system. This did notgo smoothly, and the many problems that re-sulted from this effort frustrated and angeredmany citizens. This situation helped create aclimate that discouraged constructive commu-nity debate and consideration of importantwater information.

Tucsonans now must grapple with thequestion of how best to ensure a long-term wa-ter supply for the community. This involves ex-amining various options, with special attentiondevoted to finding ways to more effectively usepresent supplies. Further, if CAP water is to bepart of the solution to Tucson’s water supplyproblem, the community must find the waysand means to use this renewable source that are

both affordable and acceptable to Tucsoncitizens.

The many thousands of people who havemoved into the Tucson metropolitan area inthe past 50 years are using millions of gallonsof water daily. Most of that water is “old” wa-ter, stored underground forhundreds or thousands ofyears. Because more “old wa-ter” is used each year than isreplaced by precipitation, ei-ther by rain or snowmelt fromsurrounding mountains, watertables decline and wells mustreach deeper and deeper totap remaining water. If we donot reduce the amount of wa-ter we use and/or unless weutilize a new dependable sup-ply, we will suffer the conse-quences of our excessivereliance on groundwater.These include the increasedcost of pumping from greaterdepths, decreased water qual-ity and the occurrence of sub-

sidence which can threaten structures, homes,streets and utilities.

Figure 2 shows major water demand catego-ries and sources of water supply for the Tucsonarea. What is readily apparent is that municipal

Preface How, ultimately, do we make a rich, a full, a complete water policy? The beginning of the

answer is that a great many factors must go into any natural resources policy in the

American West, for these are complex times. Water means too many things to too many

people for it to be pat, one-dimensional, bound up in a single ideology... Another, related part of

the answer is that we must move away from jargon, from bland words and thinking that

dehumanize what ultimately are intensely human, even spiritual matters.

—Charles Wilkinson, The Eagle Bird, 1992

Figure1 View from “A” Mountain at the end of the twentiethcentury. Photo: UA Biomedical Communications.

uses represent the greatest demand and minedgroundwater is our primary water source.

Our largest new water source is the CAPwhich brings water from the Colorado River.

Because first efforts to introduce CAP water inTucson met with serious problems, a majorityof voters subsequently rejected its use in theirhomes unless certain conditions were met. Tuc-son Water, Tucson’s largest water utility, ismaking efforts to meet those conditions. Whencontemplating CAP water use the public needsto understand how its use will affect theirhomes and lives and the costs involved to mini-mize any adverse impacts. Tucsonans could

then better evaluate CAP options compared toother kinds of water management actions.

Other community water issues also need at-tention. For example: Who should help pay toprolong the usefulness of the aquifer? Shouldthis be the obligation of all water users or justthose users who actually use alternative suppliessuch as CAP and effluent? Should the minesand farms be required to use CAP water or atleast help pay for it? Other management issuesthat need addressing include: Should all Tuc-son Water customers have a say in Tucson Wa-ter policy? Should there be morecomprehensive basin-wide management of wa-ter supplies? Should there be further limits ontotal water use? The report notes areas where in-formation for making necessary decisions islacking. The authors do not recommend anysolution, but instead have presented facts andinformation to assist citizens anddecision-makers.

As is evident from its title, thispublication is about thesustainability of our water resources.Sustainability is a popular wordnowadays, often heard when naturalresources is the topic of discussion.Used in varied contexts, in govern-ment reports, academic journals andthe popular press, sustainability isnot easily summarized in aone-size-fits-all definition. One pointof shared understanding, however, isthat sustainability is a desirable goal.

At one level, sustainability,when referring to water resources,means we are not consuming morewater than can be renewed. Sus-

tainability implies a balance between supplyand demand. For example, groundwater is notan unlimited resource. If we use groundwatersupplies at a greater rate than the aquifer is re-charged, we are violating the principles ofsustainability. Groundwater use at that level isnot sustainable. This definition generally corre-sponds to the definition of safe yield, which isthe management goal of the Tucson ActiveManagement Area (TAMA).

Sustainability also has a broader definition,one that takes into account social, economicand environmental values. In this context, asustained water supply involves more thanmatching water demand with supply.Sustainability also means that our water re-sources are managed in a way to preserve theenvironment, to maintain the economy, and toensure that all water users share equitably in

Water in the Tucson Area: Seeking Sustainability

vi

Figure 2 Water demand and supply in theTucson AMA (1997 conditions)

This photo has been removed due to copyrightrestrictions on the web

Figure 3 View from “A” Mountain at the end of thenineteenth century. Photo: Arizona Historical

Society/Tucson.

reaching and maintaining a balance betweenwater supply and demand.

Both definitions, but especially the latter,involve a shift in mind set. What is involved isless emphasis on developing new water sup-plies, which has been the traditional approach,with more attention devoted to learning to usewater in a way that allows current and futureusers to live in balance with nature and one an-other.

One final point: The geographical area cov-ered by the report needs defining. Tucson asthe “study area” of this report covers more ter-ritory than what is bounded by city limits. Thispresents some difficulties. Defining a “studyarea” is complex and often contextual. Themost common term used in this report is the“Tucson area.” This term is meant to encom-pass the most heavily populated portions ofeastern Pima County, from Avra Valley on thewest, to the Rincons to the east, and fromGreen Valley on the south, to Pinal County onthe north. These boundaries are approximateand are intended to roughly delineate an areain which there are extensive political andhydrologic connections.

The maps in this document show most ofthe Tucson area, with the exception of GreenValley. (See Figure 4.) The choice of map extentrepresents a compromise between showing suf-ficient detail in the most heavily populated ar-eas and showing the larger geographic extent.The map boundaries are not intended to be ab-solute.

In many instances this report refers tomore specific boundaries, usually in the con-

text of the source of availabledata. For instance, many of thedata in this report come from theArizona Department of Water Re-sources’ Tucson Active Manage-ment Area. TAMA is based, inpart, on groundwater basinboundaries.

An effort has been made tobe both precise and consistent inthe use of terms and geographicextent. The reader should beaware, however, that there is someinherent “fuzziness” in these defi-nitions, due to overlapping politi-cal and hydrologic boundaries.

Each of the following chap-ters begins with a brief summary of its content.Background information then is provided ontopics crucial to understanding Tucson’s waterdilemma. The final chapter offers readers anopportunity to make their own choices from arange of options, based on the information inthe previous chapters.

If this report can be said to have a single,underlying message, it is that there is no onesimple, inexpensive solution to our water prob-lems. Each proposed solution has both positiveand negative impacts.

All of us — Tucson Water customers, pri-vate utility customers, farmers, miners, indus-trial water users and those with their own wells— have straws in the same glass. What we do af-fects everyone else. The challenge for the com-munity is to pick an effective and desirablesolution at a price it is willing to pay.

This report was funded entirely by the Uni-versity of Arizona and was produced by the UAWater Resources Research Center as a service tothe community. Its intent is to provide useful,accurate information for Tucson citizens to usein making water decisions. The authors believeboth scientific information and communityvalues have important roles to play in decidingwater issues. With this in mind, the authorshave collected information from a wide varietyof sources including federal, state and localagencies’ reports, university research, informa-tion from private water utilities and studies bynonprofit groups. Although staff members oflocal agencies were consulted at various timesduring the preparation the report, the WaterResources Research Center researchers definedthe issues and summarized the informationwith the assistance of other university experts.

Preface

vii

Figure 4 Study area.

Southern Arizona is located within a physio-graphic region called the basin and rangeprovince. The region, which stretches from

Nevada southeast to northern Mexico, is char-acterized by mountain ranges running in aroughly north-south orientation, interspersedwith broad flat valleys or deep basins. (See Fig-ure 1-1.)

Tucson is located within a broad valley,with mountains on each side — Santa Catalinasto the north, the Rincons to the east, the Tuc-son Mountains to the west and the Santa Ritasto the south. Most of the population of thegreater Tucson area lives in the Santa CruzValley.

About 10,000 years ago, before the climatebegan to get warmer and drier, much moremoisture reached the basin than does today.Water isotope studies show that much of thewater now stored underground fell as rain dur-ing these ancient times. The alluvial soil thatholds the subsurface water is called the aquifer.Alluvial soil or alluvium, which consists ofclay, sand and rock, washed from the surround-ing mountains and accumulated over manythousands of years. Groundwater is stored inthe open spaces between the particles of sandand rock within the alluvium.

As is shown in Figure 1-2 various watercourses transect the area. When flows occur, theSanta Cruz River runs north-northwest throughthe area, and the Rillito Creek runs fromsoutheast to west, connecting with the SantaCruz River near Orange Grove Road. ThePantano Wash flows northwest and enters theRillito Creek before the Rillito connects withthe Santa Cruz River. In years ofheavy precipitation, some waterwill flow north to reach the GilaRiver west of Phoenix, then con-tinue to the Colorado River andthe Gulf of California. But inmost years, flows do not get thatfar.

The basin’s low annual pre-cipitation results in very fewstreams or rivers with perennial(year-round) flow today. Themost notable exception, SabinoCreek, begins at relatively highelevations and is supplied bysnowmelt as well as rainfall.Most of the rivers, streams andwashes in the Tucson Basin areephemeral (i.e., they flow onlyimmediately after rains). Overallscarcity and variability of flow

has made surface water an unreliable andlargely impractical water supply for a large pop-ulation.

Historically, the groundwater table in theTucson area was much higher, and surface wa-ter and groundwater were connected alongmuch of the Santa Cruz River. At that time thewater table was high enough to feed the river.

1

Chapter 1

The SettingT

his first chapter sets the scene by describing the climate and terrain of the Tucson area.

Ultimately, climate and terrain determine water availability, from the occurrence and

extent of precipitation to the storage of groundwater. Water availability — or, stated

differently, water scarcity — in turn determines the course of human life in the area, from

population densities to economic activities.

Figure 1-1 Tucson is located within a basin and rangeprovince with alternating mountains and valleys.

Photo: Arizona Geological Survey.

This no longer occurs because the water tablelevels have dropped far below the surface dueto groundwater pumping.

CLIMATIC INFLUENCES

Global CirculationAt 32.2° north latitude, Tucson lies along

an arid and semi-arid zone that stretches fromNorth Africa (Marrakech 31.2, Tripoli 32.7),the Middle East (Jerusalem 31.8, Baghdad 33.3),across Southwest and South Asia (Iran, Afghan-istan, Pakistan), and into Central Asia (Tibet).(See Figure 1-5.) Air over the equator heats,rises, loses moisture and then sinks at about 30degrees north latitude, creating large cells ofstable high pressure. With low moisture con-tent, and little to disturb the airflow, precipita-tion is sparse and infrequent along this globaldesert zone.

Tucson PrecipitationAn annual average of 12 inches of rain falls

within the Tucson Basin. Rainfall varies greatlyaccording to the season and the location withinthe area. The mountains ringing the basin, par-ticularly the Santa Catalinas, cause some localuplifting of air masses (orographic effect) re-sulting in annual precipitation as high as 28inches on Mt. Lemmon. The east side of themountain range gets less rain than the rest ofthe range.

The precipitation arrives in two distinctseasons. Fifty-two percent falls during a sum-mer “monsoon” (July–September) and 28 per-cent from December through March. In thesummer, as land temperatures rise, dense, moist

air from the Gulf of California and Gulf ofMexico is drawn inland. In the afternoon, astemperatures reach their peak, the moist air ispushed upwards, forming large thunderheads.Summer “monsoon” rains are characterized bybrief but intense thunderstorms with highly lo-calized precipitation. (See Figure 1-3.)

In the winter, large fronts develop over thePacific Ocean. The global circulation patterns,and specifically the jet stream, carry these

storms eastward. The persistent high pressurenormally diverts the jet stream and storms awayfrom the Southwest. In the late fall, however,the high pressure cell is weakened and can bedisplaced, allowing large, slow-moving fronts topass over the Tucson Basin. Winter rains arecharacterized by heavy cloud cover and precipi-tation that persists for many hours or even sev-eral days and covers most of the area.


2

Figure 1-2 Tucson area mountains and rivers.

Sources: United States Geological Survey, Pima County, Water Resources Research Center.

Precipitation in October and November(about 14 percent of annual rainfall) is quitevariable from year to year and is often a resultof severe storms or Pacific hurricanes that“graze” the region. These storms can produceflooding, often over large areas. These rainfallpatterns are distinctive of the Sonoran Desertand explain the extraordinary vegetation of thearea. The Mohave Desert to the west of Tucsondoes not receive as much summer rain, and theChihuahuan Desert to the east gets less winterrain than the Sonoran Desert.

The year-to-year variation ofprecipitation in the Tucson Ba-sin is quite substantial. (See Fig-ure 1- 4.) Global phenomenasuch as El Niño and La Niña af-fect the distribution and magni-tude of precipitation. Winterprecipitation in 1992/93 and1997/98 was as much as 55 per-cent higher than the winter aver-age in the Tucson Basin.

EvapotranspirationClear skies and a relatively low latitude

make Tucson one of the warmest areas in theUnited States. Average summer highs are in the

upper 90s with peaks above 110° F. These hightemperatures, along with low relative humidity,contribute to very high water loss throughevapotranspiration. (Evapotranspiration is thecombined effect of surface evaporation andtranspiration by plants.) The potentialevapotranspiration rate averages about 77inches per year which is about 6.5 times greaterthan the approximate total annual precipita-tion in the area. Most of the precipitation thatfalls in summer storms evaporates without be-ing used by plants or people or being rechargedinto the aquifer.

Chapter 1. The Setting

3

Figure 1-3 Summer storms in the area often are confined to isolatedlocations. Photo: David Bright, U.S. National Weather Service.

Figure 1-4 Climatological factors 1987-1998.

Source: U.S. National Weather Service.


4

Figure 1-5 Location of cities along 30E “arid zone”

5

THE SEARCH FOR WATER

The history of water use in the Tucson areais primarily one of reaching out fartherand farther to provide enough good water

for a growing community. From the first watersuppliers who brought water from springs orthe Santa Cruz River to today’s Central Ari-zona Project (CAP), which lifts water 2,900 feetthrough 14 pumping plants, delivering it 335miles from the Colorado River, people havelooked for new and reliable sources of goodquality water. Attempts to persuade people toconserve water also have been part of the pic-ture for more than 100 years, as have been pro-jects to utilize new technologies to increasesupplies. People have proposed various projectsover the years including dams to capture floodwaters so this resource could be used ratherthan “wasted.” Tucson also has experienced oc-casional water quality problems for more than100 years. And finally, politics has played a ma-

jor role in many sig-nificant water deci-sions over the century.

Santa Cruz RiverThe first people

who lived in the Tuc-son area got their wa-ter from the SantaCruz River or fromsprings that bubbledto the surface at thebase of Sentinel Peak(now called “A”Mountain), BlackMountain near SanXavier Mission andseveral other spots.Enough water wasavailable to satisfy the needs of a few thousandpeople, including irrigating crops. In fact,

Santa Cruz River water has been used to irri-gate farms for at least 2,000 years. The Santa

Chapter 2

LOOKING TO

THE PAST TO

UNDERSTAND

THE PRESENT

Chapter Two summarizes Tucson’s water history from the days of

carrying water in olla or buckets from rivers and springs to our

ability today to turn on the tap and get as much water as we

desire. This change demonstrates how for over 100 years we have

looked to more distant sources for a dependable water supply, starting

with a pipeline from the Santa Cruz River and continuing into the

present with the CAP canal carrying water from the Colorado River.

The chapter also shows that the influence of politics on wateraffairs began early in Tucson’s history.


Figure 2-1 Rincon Mountain Water truck from the early twentiethcentury. Photo: Arizona Historical Society/Tucson.

Cruz River was not a big river like the Colo-rado or Gila rivers, but the river did flow mostof the time in the Tucson area. The Hohokamcaught edible fish in the Santa Cruz, and earlypioneers hunted water-loving muskrats. WhenFather Kino came to the area in the late seven-teenth century, he stated that he believed therewas plenty of water — enough to support alarge town of 5,000 people.

Fort Lowell’s WaterworksWhen the U.S. Army established Fort

Lowell near the Rillito Creek in 1873, the watersupply in the area was plentiful. Acequias (ca-nals) brought water from the river; windmillspumped groundwater from about 35 feet down;and storage tanks held water at points of highelevation to provide running water to all the

buildings. But prob-lems arose. The wind-mills often wereinactive for days at atime, and even whenwater filled the storagetanks, the water was hotand unappealing. Dis-eases were blamed onthe bad water whichwas polluted by live-stock, people and un-sanitary water storagefacilities. “Squatters” di-verting surface waterfor their farms pro-voked conflict. Debateraged about whether topurchase a steam- pow-ered pump to get water

from greater depths or import water fromSabino Canyon. The military built larger stor-age tanks, installed the steam pump and aban-doned the Sabino Canyon project. By the timethe fort was closed in 1891, the water problemhad been solved by installing additional wells.

19TH CENTURY SUPPLIES

Before the American Civil War, Tucsonwomen washed their clothes in the Santa CruzRiver, with a guard nearby as protection againstApaches. Drinking water was available from awell inside the walled city or from the well onBishop’s Farm. El Aegypti Spring (near theWishing Shrine, south of the present TucsonCommunity Center) was a reliable water source

for many years, but few people dared to venturealone so far outside of town, even for water.

After the end of the Civil War and the de-feat of the Apaches in the late 1860s, more andmore people moved to Tucson, which becameArizona’s most important city. The services ofa water carrier were needed to supply the grow-ing population. The water carrier got his waterfrom El Aegypti to deliver to homes in bags onhis burro. Later Adam Saunders and Joe Phymodernized the system, using a two-wheeledcart for delivery at five cents a bucket. At thishigh price, fresh water was seldom used for wa-tering plants. Instead people used waste waterfrom their washing for this purpose. AdamSanders built a bath house at El Ojito, where

rich and poor alike (but only males) could gettheir occasional bath for twenty five cents. Adaily bath was considered a downright “wasteof water.” W.C. Davis installed Tucson’s firstpersonal bathtub in a home on Congress Streetsometime in the 1880s. The uses of water wereincreasing.

Entrepreneurs built dams in the SantaCruz River near the base of Sentinel Peak, back-ing up water into lakes which were used for


6


Figure 2-2 A well at Fort Lowell in the 1880s. Photo: ArizonaHistorical Society/Tucson.

“A tenacious eastern dream to convert the desert into

a garden characterized Tucson Basin water control

history since the Gadsden Purchase in 1854. The

reactions of American settlers to a series of water

supply crises demonstrated the persistence of this theme.

When faced with each crisis, Americans responded by

applying an increasingly sophisticated technology to

the problem of water scarcity.” Kupel, page 162.

boating and fishing as well as to power flourmills. These lakes were destroyed by floodsduring the 1890s and not rebuilt.

Obtaining a reliable supply of potable wa-ter was a problem even in the early days. In1870, John Bourke complained of the manyholes in the town which he said were aban-doned wells. “... wells, which were good andsweet in the first months of their career, butgenerally became so impregnated with ‘alkali’that they had to be abandoned; and as lumberwas worth twenty five cents a foot, and there-fore too costly to be used in covering them,they were left to dry up of their own accord,and remain a menace to the lives and limbs ofbelated pedestrians.” He describes an incidentin which an inebriated citizen fell down anempty 25-foot well.

The area near Sentinel Peak was dominatedby farms with a network of irrigation ditchesthat directed water from rivers and springs.These uses left little water in the river north ofthe Congress Street Bridge. During the 1870s,the city made three attempts to increase the wa-ter supply. The city contracted to have artesianwells drilled, but that effort failed. The cityawarded another contract to a well driller whowas to receive one block of city land for everysuccessful well drilled, but that effort also cameto naught. Some entrepreneurs south of townstarted building a canal to bring water to Tuc-son from Canoa (near present-day Green Val-ley), but that, too, proved unsuccessful. By the1880s, many people had their own windmills,but the windmills often were still during thedry months when little wind was blowing. Thedemand for water had become so great thatsprings were no longer dependable.

The then-re-cently formed Tuc-son Water Companygets credit for firstsuccessfully tappinga new water source.With a franchisefrom the city, thecompany built a dis-tribution system tobring water from Va-lencia Road todowntown Tucsonvia a redwood flumelaid in the river anda 4.5-mile-long waterpipe made of sheetmetal coated withtar. Following thissuccess, the TucsonWater Company in1889 installed itsfirst steam-driven pumping plant and dug a40-foot deep well, capable of pumping 1,250gallons per minute. Water came to town alongthe alignment of what is now Osborne Street,which is why a diagonal street is there today in-stead of the north-south, east-west grid com-mon in other older sections of town.

This new water source would have solvedthe supply problem if Tucson’s population hadnot continued to grow and if droughts did notperiodically occur. In 1892, the City Councildebated limiting irrigation to nighttime hoursbecause of water shortages, but did not pass theordinance. The mayor, however, ordered thewater supply to city parks be cut off. It was notuntil 1903 that the City Council (which now

owned the water company) passed an ordinancelimiting irrigation to between 5 a.m. and 8 a.m.and between 5 p.m. and 8 p.m., with a maxi-mum fine of $50 for violations.

EARLY 20TH CENTURYEXPANSION

In 1900, the City of Tucson bought theTucson Water Company and its southside wellsfor $110,000 and formed the Water and Sewer-age Department. Hetty Green, a wealthy NewYork financier, bought the bonds to financethe purchase. Things did not go smoothly atfirst. In 1908, Mayor Heeney decided to removethe water superintendent without consulting

Chapter 2. Looking to the Past to Understand the Future

7


Figure 2-3 The Parker and Watts Water Company office in the latenineteenth century. Photo: Arizona Historical Society/Tucson.


8

the City Council. As Councilman MosesDrachman explained, “The row which this pre-cipitated lasted to December of that year andfinally resulted in the council removing MayorHeeney from office for misconduct.” (Manyother differences of opinion and accusations ofscandal also contributed to the mayor’s dis-missal.) Also in 1908, the city faced its firstwater crisis when a new residential district wasestablished, way out in the country between theUniversity of Arizona and the railroad tracks.The windmills installed on home sites couldn’t

produce enough water so resi-dents demanded that the cityextend the water system to ser-vice the district. The city autho-rized the water superintendentto spend $260,000 to expandthe system northward. In 1911,when citizens started complain-ing of their water bills, whichwere based on a flat rate permonth, the city installed me-ters, at first only for the com-plainers and later for everyone.From then on people paid ac-cording to use.

In 1914, another bond issuefinanced six new wells and areservoir, at the far east side oftown at Second and Campbell.A new pumping technology wasinstalled that could produceone millions gallons of waterper day from one well. Wind-mills could extract water fromshallow wells, but the new gasor electric pumps were muchmore efficient and could lift

water from greater depths.By 1920, water shortages again were a prob-

lem, and the City Council again banned water-ing except between 5 a.m. and 8 a.m. and 5p.m. and 8 p.m. with a maximum fine of $50for violations. The City Council also hired astaff person to provide water conservation in-formation to the public. Meanwhile more wellswere dug north of town to improve the watersupply and increase water pressure for fightingfires. Over the years, more wells were added ei-

ther by buying private water companies or bydigging wells, until a peak of 61 wells wasreached on the north side, eight of which arestill active today. By that time the system hadexpanded and parts of the city were as much as80 feet higher than downtown. To accommo-date the situation, the city was divided into twoseparate pressure zones. Water circulated sepa-rately in each zone, because it could not easilybe lifted to the higher areas. In later years, thezones were connected with booster stations.

Wells were generally around 50 feet deep atthis time, but water levels were dropping, andpeople with shallower wells had problems.Groundwater pumping near the Santa CruzRiver began to affect river flow, but not untilthe 1940s did this pumping finally caused thewater table in the area to drop so low that theriver flowed only during floods. During the1930s and 1940s, population growth slowed. Inresponse, the water system expanded less rap-idly, although the city drilled ten new wells

Figure 2-4 The growth of the City of Tucson.

Figure 2-5 Population of Pima County,1850 to date.

Source: Arizona Department of Economic Security.

and purchased several water companies duringthis period.

Growth and ControversyAfter World War II the pace of population

growth quickened, and by the 1950s, thesouthside and northside wells could no longerproduce enough water. The Arizona Daily Starheadline read “More Water is UrgentlyNeeded.” (July 23, 1952) “Living in desertcountry, where a rainbucket on the roof would-n’t provide more than a good shampoo, it isnatural to wonder if the city can furnish suffi-cient water to meet this modern expansion. Theanswer is a big YES, according to Water Super-intendent Phil J. Martin, Jr., if the proposed$5,500,000 water revenue bond issue is giventhe nod by voters Aug. 12.”

The big bond issue passed, and a series ofwells was drilled between 1954 and 1968 alongOld Nogales Highway, south of Valencia Roadon the edge of the San Xavier District. Someprivate wells in the area also were purchased,for a total of 34 wells, 15 of which are still ac-tive today. The area is called the Santa CruzWellfield. This additional pumping contributedto further lowering of the area’s water table,,causing the extensive mesquite bosque south ofSan Xavier Mission to die in the 1950s. Waterproblems at San Xavier intensified.

By the 1960s, population had increased tothe extent that even these three establishedwellfields did not provide enough water. Thecity began to purchase farms in the Avra Valleyto the west to gain access to their wells. Theplan was to bring the water to the city througha large pipeline. During its period of peak oper-

ation, 27 wells were operating inthe Avra Valley area, 20 ofwhich are still active. The cityalso purchased land along theSan Pedro River north ofBenson to obtain water rights.The plan called for constructionof a pipeline over the mountainpass to bring San Pedro Riverwater to Tucson. This pipelinewas never built, and the city ulti-mately sold the land.

During this time, the cityalso was buying water companiesand their wells throughout thecity limits. When a new area wasannexed, the city would offer tobuy the water company. Havingall the water service under citycontrol had the advantage ofproviding uniform water serviceand assuring adequate pressurefor fire fighting (See Figure 2-6).Some areas such as Flowing Wells andWinterhaven never came under city control.The collection of almost 300 city-owned wellsin the central city area is referred to as the Cen-tral Wellfield, although it is not a coherent sys-tem, but rather a collection of former privatesystems and some city-drilled wells. In 1998,185 wells were active in this area

Starting in the 1960s the city adopted apolicy of buying water companies outside citylimits. The city also extended its water serviceoutside city limits in areas not served by othercompanies. The purpose of this strategy was toenable the city to engage in basinwide manage-ment of water supplies. This would promote

more equitable water service and allow sharingof costs to augment the supply. This patchworkof water systems often caused problems. Watermains had to be connected to the central sys-tem in most cases, and the quality and size ofthe wells and pipelines varied greatly. Servingwater outside city limits also meant that manycustomers would have no vote on water mattersand no representation on the City Council thatdecided water issues.

CONTROVERSY OF 1975-76

The 1970s were a period of turmoil for thecommunity. Advocates of “controlled growth”


9


Figure 2-6 One of Tucson’s first fire brigades. An adequatewater supply to fight fires has long been an important civic

planning goal. Pressure and volume must be sufficient to fightfires during times of peak summer demand.Photo: Arizona Historical Society/Tucson.

gained a majority on the City Council and alsowere a significant presence on the Pima CountyBoard of Supervisors and in the Pima Countydelegation to the Legislature. Congress had ap-proved the CAP, and Tucson had to decidewhether to contract for CAP water. The con-trolled growth advocates were skeptical aboutCAP, questioning its cost, need, long-term reli-ability and the quality of the water. They alsoargued that controlling sprawl was an appropri-ate strategy to discourage a rapid increase in thecost of water. They supported much strongerwater conservation efforts and less agriculturaluse of water.

Controlled growth advocates on the Tuc-son City Council soon found an opportunityto press for change by dealing with the pres-sures facing the Tucson Water Department. Thedistribution system was expanded rapidly inthe early 1970s to keep up with growth. Reve-nues from relatively low water rates were notenough to keep up with increasing costs andthere was not enough system capacity to meetpeak demand during hot summers, such as thesummer of 1974. To address the problem, aconsultant’s report recommended a six-yearprogram of improvements to the distributionsystem, to be financed by bond sales, higher wa-ter rates and system development charges. Wa-ter rates would be designed to recover theactual costs of providing service, including a“lift charge” for providing water to customersat higher elevations, such as those in the foot-hills. System development charges would be ap-plied to new customers to help pay forexpansion of the system.

In 1976, the City Council voted for a waterrate increase designed both to keep up with in-

flation and to recover actual costs of delivery.The new rates included the lift charge and re-tained the progressive rate structure (i.e., peoplewho use water above certain amounts werecharged higher rates for water consumed abovethat amount) which was first used in TucsonWater’s rate structure in 1974. The new rateswere adopted in June, and water bills of somecustomers in the high lift zones quadrupledfrom June to July, while bills of many othersdoubled.

The pro-CAP and pro-growth forces en-couraged an angry public to revolt, and theCity Council majority was recalled even thoughthey rescinded the lift charge in August. Afterdiscovering that rates had been raised not tocontrol growth, as had been assumed, but to

build distribution systems and gain new watersupplies to meet expected growth, their succes-sors retained the rest of the new rate structureand even raised the rates again. The impact ofthe recall continues to this day, with CityCouncil members and water staff reluctant tomake major changes to water rates in fear ofangering water customers. “Remember the re-call” remains a formidable slogan.

At the next regular election in 1978 con-trolled growth advocates were defeated in theBoard of Supervisors and the Legislature, andthe City Council approved Tucson’s CAPsub-contract. The sub-contract was for the en-tire metropolitan area, based on the assump-tion that the city system would continue toexpand. The Council also approved water con-servation programs, and Pete the Beak, cartoonstar of the Beat the Peak program, was hatched.The program was originally designed to encour-age landscape watering at non-peak hours,thereby delaying the need for expanding thesystem of water mains and reservoirs. The pro-gram, however, also had the effect of encourag-ing water conservation more generally.

During the 1980s, the city increased its wa-ter conservation efforts, partly in response tothe requirements of Arizona’s new Groundwa-ter Management Act. Tucson had some of thelowest rates of per capita water consumption inArizona because of these programs and the per-ceived high cost of water. The metropolitanarea expanded rapidly beyond the central areainto higher elevations. Since the main watersupplies were at the lower elevations, thismeant water had to be pumped uphill andstored in reservoirs, to flow by gravity to cus-tomers. The fact that all customers pay the


10

Figure 2-7 Groundwater pumping in theUpper Santa Cruz River Basin from

headwaters to Pinal County.

Source: Arizona Department of Water Resources.

same rate no matter where they live is an ad-vantage to those living in more distant andhigher areas.

CENTRAL ARIZONA PROJECT

The CAP is a system of canals, pumping sta-tions and storage facilities that brings water 336miles from the Colorado River at Lake Havasueast to the Phoenix area and then south to theTucson area. Fourteen pumping plants lift wa-ter 2,400 feet in elevation to the terminus.

The CAP idea preceded Arizona statehood.In the early years of the twentieth century somevisionaries talked about bringing ColoradoRiver water to central and southern Arizona. Atthe time this seemed infeasible. Meanwhileevents were transpiring to make the vision areality.

In the 1920s, six of the seven ColoradoRiver states agreed to divide the river water. Ar-izona was the sole dissenter and did not goalong with the agreement for more than twelveyears. Meanwhile Hoover Dam was built in the1930s, along with other Colorado River pro-jects. When a large aqueduct was built to sup-ply southern California with Colorado Riverwater in the 1940s, Arizonans took notice andbegan lobbying for their own project. By 1960,all major Arizona politicians and political in-terests were behind the project. Congress ap-proved CAP in 1968.

The original project included dams on theupper Gila River in New Mexico, the middleGila River in Arizona, the San Pedro River, andthe Verde River at Fort McDowell. Ultimatelynone of these dams was built. Instead changeswere made to some existing dams, and a new

dam was added along the Agua Fria River. Con-struction began.

President Carter expressed doubts about theproject-building approach to solving westernwater problems, and demanded changes in Ari-zona water laws to promote conservation. TheArizona Legislature responded to the threat-ened loss of CAP funding by passing theGroundwater Management Act of 1980. Athree-county water district was formed to man-

age the project after completion and to developwater subcontracts with cities, farms, mines andother prospective users.

Completed to Tucson by 1990, the projectfaced problems. Few farms or mines signedCAP contracts, not even those that once enthu-siastically supported the concept. Farmersfound the cost too high and the supply too un-reliable. The mines were concerned that thequality of the water would affect their mining


11

Figure 2-8 Original extent of CAP delivery areas.

Sources:Tucson Water; Pima County Technical Services; Water Resources Research Center.

processes. The cost of extending pipelines to in-dividual farms and mines also was a significantfactor. The City of Tucson was virtually theonly commercial customer for CAP in PimaCounty, although water was allocated to theTohono O’odham through a legal settlement.

Since Tucson Water has by far the largestmunicipal CAP contract, its customers, by sup-porting CAP, pay the majority of the costs toaugment the water supply. Farms, mines andwater companies meanwhile can continue to

pump groundwater at a relatively low cost.Many people believed that other water users inthe basin should be required to use CAP waterand/or to share the costs of those switching torenewable supplies. Arizona law, however, hasno provisions to enforce such a requirement.

To many people, however, CAP water rep-resented a long-awaited water source to benefitthe Tucson area. With CAP on-line, lessgroundwater would be pumped. CAP’s Colo-rado River water, however, differed from thegroundwater to which most people in the areawere accustomed. CAP water is harder and con-tains more total dissolved solids than localgroundwater. Despite this situation officials be-lieved that citizens would find the new watersource to be acceptable.

As the CAP canal neared completion in1989, the Tucson City Council adopted theTucson Water Resources Plan for the 110-yearperiod, 1990-2100. It called for an aggressivephase-in of direct use of CAP water, combinedwith recharge and recovery of excess CAP waterin early years, recovery of recharge credits, reuseof effluent and some continued use of ground-water. There was a heavy media campaign sur-rounding the introduction of CAP water,including a well publicized taste-test, TV and ra-dio ads, and direct-mail fliers. The only sub-stantive warnings about water quality weredirected at kidney dialysis patients, those on re-stricted salt diets, and aquarium owners. Ingeneral, the introduction of CAP water was ex-pected to go smoothly.

Starting in November 1992, CAP water wasdelivered to approximately 84,000 customers,or about 58 percent of the connections in theTucson Water service area. Problems were soon

reported by some customers. Many peoplecomplained of red, brown or yellow-colored wa-ter coming from their taps. Some reported bro-ken pipes, damage to water-using appliancessuch as water heaters or evaporative coolers,skin rashes, and even dead fish in aquariumsand damage to pools.

Many customers receiving CAP watersought to avoid some of these unpleasant ef-fects by buying bottled water or in-home treat-ment systems, such as filters installed under thesink. Figure 2-10 shows the increase in bottledwater usage by Tucson Water customers in re-sponse to the introduction of CAP water inNovember 1992. Purchases of both bottled wa-ter and in-home treatment systems have beenrising on a national basis for a number ofyears, and aggressive marketing of bottled waterby a growing number of bottled water outletsled to an increase in bottled water usage for allTucson Water customers over this time period.However, customers switched from groundwa-ter to CAP water increased their bottled waterusage more than ten fold, compared to a tri-pling in the rate of bottled water usage forthose kept on groundwater.

Research by the Water Resources ResearchCenter revealed a similar pattern for purchasesof in-home water treatment systems, as custom-ers with in-home treatment systems increasingfour-fold to nearly 20 percent. The study alsodocumented dramatically higher rates ofplumbing and water-using appliances failing inhouseholds switched to CAP water. While anaccurate estimate of all costs could not bemade, the study suggested that Tucson Watercustomers receiving CAP water were incurringmany millions of dollars of expenses per year


12

Figure 2-9 Aerial view of the CentralArizona Project canal. Photo: Central Arizona

Water Conservation District.

to avoid and compensate for the decreasedwater quality.

The City Council debated the possibility ofending direct delivery of CAP water, but in Au-gust 1993 twice voted by narrow margins tokeep delivering CAP water. In October 1993,deliveries were halted to the east side of theCAP delivery area, which generally had a highnumber of older galvanized steel water mainsand was most heavily affected.

As more complaints were reported, TucsonWater responded by adding a corrosion inhibi-tor to the water as it left the treatment plant.However, maintaining effective corrosion in-hibitor levels throughout the distribution sys-tem proved difficult. The utility also beganfrequently adjusting the chemistry of the waterin an effort to control the problems. Severaldifferent levels of pH adjustment were tried for

varying lengths of time. These fre-quent changes in pH level were lateridentified as probably contributing tothe problem rather than correcting it.

The City of Tucson also set up aprogram to handle damage claims.While not admitting fault or responsi-bility for damages, the City offered topay up to specified amounts to reim-burse for specific types of damage.As of 1995, the City had paid over $1million dollars in damage claims, andhas since added to this amount.

Public exasperation with the deliv-ery problems grew as damage tohomes mounted and the extent ofthe problem became apparent. InMay 1994, voters surprised some ob-servers by approving $31 million in

bonds for improvement of the water deliverysystem, mostly to replace old galvanized steel oriron water mains.

All CAP water deliveries had to be haltedin November 1994 to allow for repairs to si-phons in the CAP system, and City Councilvoted not to resume deliveries. By this time,the head of Tucson Water and the CAP plantmanager had resigned, and the utility’s reputa-tion had been seriously damaged in the eyes ofmany citizens.

Petitions were circulated for a ballot issueto limit future direct delivery and in November1995, voters approved the Water ConsumerProtection Act (WCPA), which outlawed directuse of CAP water unless it was treated to thequality of Avra Valley groundwater and wasfree of disinfection by-products (See chapter 7).The WCPA had the effect of shifting the focus

for how to use CAP water in Tucson to artifi-cial recharge. In 1997, voters reaffirmed theiropposition to direct use of CAP water in favorof its recharge and use by farms and industry,by defeating a ballot initiative which wouldhave repealed or substantially changed many ofthe provisions of the WCPA. Some citizensalso joined a class-action lawsuit against theCity. Resolution of this litigation is pending.

TODAY’S WATER PROVIDERS

Tucson Water now has four majorwellfields — Southside, Santa Cruz, Central andAvra Valley — along with a large number ofwells scattered throughout the city, and a fewsmall isolated systems in remote areas. In addi-tion, more than 30 water companies operatewell systems in the Tucson area. The largest ofthese are Metropolitan Domestic Water Im-provement District, Oro Valley Water Depart-ment and Flowing Wells Irrigation District.Other significant water pumpers include theUniversity of Arizona, Davis-Monthan AirForce Base, Cortaro Marana Irrigation District,Farmers’ Investment Company (FICO),Farmers’ Water Company and the ASARCOMining Co. Finally, approximately 22,000 indi-viduals and businesses have their own wells.No one agency coordinates or regulates the ac-tivities, of all these users; instead, the ArizonaDepartment of Water Resources (ADWR), theArizona Corporation Commission (ACC), theArizona Department of Environmental Quality(ADEQ), the Central Arizona Water Conserva-tion District (CAWCD), the U.S. Environmen-tal Protection Agency (EPA) and the courts allhave roles in managing water supply, water

13


Figure 2-10 Percent bottled water users over time,CAP vs. groundwater customers.

Source: Water Resources Research Center.

quality and water rates. (See Chapter 7 for addi-tional information on regulatory agencies.)

AGRICULTURAL WATER USE

People have been irrigating fields in theTucson area for at least 2,000 years. Before theSpaniards arrived, most crops were grown inthe summer, taking advantage of monsoon

rains. The Spaniards introduced winter cropsthat needed irrigation. They also introducedcattle and horses, animals that affected watersupplies as well as vegetation near the streams.The first Anglo farmers continued in the Span-ish pattern, with cooperative irrigation systemsrun by an irrigation master responsible forfairly distributing water. In 1886, the Arizona

Mining Index described Tucson farming:“Eight streams of water run through the SantaCruz Valley opposite Tucson. Five of theseditches are 7-feet wide that now contain a footand a half of running water. The other threeare narrower and contain less.” John Davidsonstarted to build a canal to irrigate 3,500 acres,but the floods of 1887 washed it out before itwas finished.

An important techno-logical advance in the1890s enabled wells to bedrilled in various loca-tions, powered withwood-burning steam en-gines and, later, gas or elec-tricity. In 1891, aUniversity of Arizona pro-fessor reported that watercould be pumped from un-derground to irrigate thecampus. About that time,the first farm in the areabegan to use pumpedgroundwater. From thenon, groundwater pumpingincreased steadily. Withthe new technology, wellscould be drilled to muchgreater depths. On the

Canoa Ranch south of Tucson a well wasdrilled to 500 feet, hitting water at 300 feet. Thenew steam pump could produce a flow of 2,000gallons per hour.

In 1892, Frank and Warren Allison built anew ditch for irrigation that was later extendedto lands beyond St. Mary’s Hospital and con-structed a reservoir near the old Warner Dam

site. By 1895, they had built more ditches andacquired another source of water known as“Flowing Wells” near Sentinel Peak as well asthe Tucson Farms Company south of town.This later developed into the Flowing Wells Ir-rigation District which stretched from farsouth of town all the way to Marana. That dis-trict continues to exist (although greatly re-duced), supplying water for urban use on thenorthwest side of town through its wells.

In the 1890s, new legal systems of appor-tioning surface water were developed, with thefirst people to file water claims having the firstrights to surface water. Water use increased tothe extent that by 1910, all of the water flowingin the Santa Cruz River in the downtown area(other than during floods) was being divertedfor agricultural or municipal purposes. Withthe growth of agriculture around Sentinel Peaknew irrigation canals were soon insufficient,and water disputes arose.

ONGOING SEARCH FORWATER QUALITY

Sewers and Wastewater TreatmentBefore the 1890s, Tucsonans used out-

houses for their sewage. In the 1890s, whenwater was first piped to houses, people drainedtheir sewage into cesspools. In 1900, the cityopened its new Water and Sewerage Depart-ment and laid the first public sewers alongMain Avenue between 17thth Street and St.Mary’s Road. The untreated sewage was deliv-ered by open ditch to a small farm where it wasused for irrigation. In 1914, people were com-plaining of the odor.


14


Figure 2-11 San Xavier Mission. The water table was high enoughto obtain water with a windmill. Photo: Arizona Historical

Society/Tucson.

When the farm had a sufficient supply ofsewage, a new farm was opened along the SantaCruz River at Roger Road, four and a halfmiles northwest of downtown, and a new pipe-line was constructed to deliver sewage water tothe farm. The city considered the farm a profit-able business, but the arrangement met with in-creased complaints. In 1928, the first treatmentplant was built which reduced the solids con-tent of the sewage. After treatment the sewagewas delivered to the farm. The facility was ex-panded and improved in the 1940s, with thesewage still used for irrigation.

As population increased, Tucson could nolonger be responsible for the sewage needs allresidents, so citizens formed a sanitary districtto serve residents outside city limits. It was notuntil 1961 that the district built a new sewagelagoon near Ina Road and the Santa CruzRiver. The Roger Road treatment plant was ex-panded in 1960 and again in 1968. The Sani-tary District was dissolved in 1968, and PimaCounty took over wastewater management forthe area outside Tucson. In 1975, Tucsonopened a Wastewater Reclamation Facility atRandolph (Reid) Park which providedwastewater for the golf course, but the facilitywas closed in 1995. Pima County built a newadvanced treatment plant at Ina Road in 1977.

By the 1970s, both city and county offi-cials felt a need to combine their efforts, andthey formed the Metropolitan Utilities Manage-ment (MUM) Agency for better basinwide man-agement of wastewater facilities in themetropolitan area. Tucson and Pima County,however, continued to operate separate facili-ties. For the first time, however, they adopted

basin-wide sewer connection fees and sewer userfees, charging the approximate cost of provid-ing services. In 1976, elected officials dissolvedMUM. Tucson and Pima County then signedan intergovernmental agreement in 1979, stipu-lating that Pima County would own and oper-ate all the wastewater systems for both city andcounty, but that Tucson would retain rights to90 percent of the wastewater coming from met-ropolitan area treatments plants. The citydeeded to the county its Roger Road TreatmentPlant and its other wastewater facilities. Be-tween 1980 and 1984, the Roger Road Plantwas expanded and upgraded in stages. The fed-eral government paid a large share of construc-tion costs, sparing county taxpayers much ofthe expense of the expansions.

In 1985, Pima County began a project toexport sludge from the wastewater process foragricultural use in the Marana area, thus lessen-ing the burden on the nearby landfill. In 1987,a system for transferring sludge from RogerRoad to Ina Road was completed. As a result,neither plant sends sludge to landfills.

In the late 1980s and early 1990s, both theRoger Road and Ina Road plants were ex-panded and modified and various smaller facil-ities were built, including the Catalina out-fallsewer and a facility in Avra Valley. Work to fur-ther expand the Roger Road facility was re-cently completed, and work is about to beginto expand the Ina Road plant. Pima Countyfunded a University of Arizona wetlands re-search project to determine how effectively wa-ter hyacinths (and later other plants) couldtreat wastewater.


15

This photo has been removed dueto copyright restrictions on the web

Figure 2-12 Woman washing clothes in theSanta Cruz River, with the ruins of the

Convento in the background. Photo: ArizonaHistorical Society/Tucson.

Recharging Reclaimed WaterIn 1983, the City of Tucson constructed a

tertiary treatment plant to further treatwastewater from Pima County’s Roger Roadplant for use on golf courses and other turf.Over the years mains were installed to deliverwater to various facilities on the far east side oftown and in the central area. Today effluent isdelivered to over 200 water consumers, includ-ing 13 golf facilities, 25 parks and 30 schools.

Starting in the 1980s the city began re-charge experiments, with pilot projects alongthe Santa Cruz River opposite the Roger RoadWastewater Treatment Plant. Recharge involvesadding water to the aquifer. Monitoring deter-mined the rate recharge was occurring and de-tected changes in water quality. The citysubsequently developed other recharge projects.The project with the largest anticipatedfull-scale capacity is the Central Avra ValleyStorage and Recovery Project.

In the 1960s, the city experimented with aseries of ponds for wastewater treatment usingeffluent from Roger Road. Then Tucson WaterDirector Frank Brooks used to boast of thehigh quality of the water by eating fish caughtin those ponds. The last of the ponds was elim-inated in the 1980s in response to fears that wa-ter leaching out of the ponds to groundwaterwas being contaminated by old landfill mate-

rial. In 1998, the city opened its first con-structed wetland to the public — the SweetwaterWetland near the Roger Road Treatment Plant.

OTHER WATERQUALITY PROBLEMS

Treatment of sewage has been the majorwater quality challenge for many years, but byno means the only one. During World War IITucson became a center of airplane construc-tion and maintenance. Several plants locatednear the Tucson Airport regularly used solventsto degrease aircraft parts. Solvents were notknown then to be a health hazard, and thewaste products were often evaporated in un-lined ponds or allowed to run into washes. Afew employees expressed concern at the time,but it was not until the 1970s that people onthe south side of town noticed the occurrenceof an unusually high incidence of certain ill-nesses. The Arizona Department of Health andthe EPA began studies to determine the cause.As a result of these studies and legal action, of-ficials came to believe that trichloroethylene(TCE) had reached the groundwater and wasprobably creating health problems such aslupus and birth deformities. A citizen group,Tucsonans for a Clean Environment (TCE),formed on the southside to ensure that the

problem was taken resolved to the benefit ofthe residents.

Since most of the manufacturing compa-nies had long since left town, Hughes Aircraft(now Raytheon), the Tucson Airport Authority,the U.S. Air Force and the City of Tucsonshared the burden of cleaning up the contami-nated water. The city shut down three produc-tion wells and brought water from other wellsto area customers. Hughes and the city in-stalled a clean-up facility, under EPA oversight.What to do with the water after the TCE wasremoved became a major concern. The issuewas later addressed as part of the anti-CAP ini-tiative or Proposition 200. This passed and be-came the Water Consumer Protection Act.Tucson voters stated that water from pollutedsources could not be used in the city system,even if federal Safe Drinking Water standardswere met.

ADEQ has identified a number of otherwater quality problems in the Tucson area, in-cluding 17 groundwater contamination sites.The sources of contamination include historiclandfills, manufacturing plants, mining and ag-ricultural activities, aircraft waste disposal, andgas station and dry cleaning operations. Insome cases the contamination exceeds federalSafe Drinking Water standards, and groundwa-ter from the affected areas cannot be used fordrinking unless treated to meet those standards.(See Chapter 6).


16

TUCSON’S WATER SUPPLIES

For many centuries, people who lived in theTucson area used less water than was avail-able from snow in the mountains or rain.

Precipitation or runoff and a high water tablecould be counted on to maintain the flow ofthe river. Those days are long gone. Today, vir-tually all the water we use originates as storedgroundwater. This groundwater also is naturallyreplenished, partly by rainwater and snowmeltfrom the mountains and partly from returnflow after various human uses, such as irriga-tion and wastewater effluent discharges. Thesurface water that replenishes the aquifer, how-ever, is not sufficient to ensure a sustainablesupply of groundwater in the face of currentlevels of demand. The stored groundwater sup-plies have not been substantially renewed formany years. In fact, our excessive pumping ofgroundwater is the reason little or no surfaceflow remains in Tucson rivers. New sources ofwater, such as CAP water and effluent, offer the

possibility that we can stop or reduce the min-ing of our stored groundwater.

NON-RENEWABLE SUPPLIES

Stored GroundwaterTwo main aquifers supply water to the Tuc-

son area, one located in the Tucson Basin andthe other in the Avra Valley Basin. In 1940,when Tucson began to increase its groundwaterpumping, these aquifers held approximately 70million acre-feet of groundwater at depths lessthan 1,200 feet below the surface. Since 1940,approximately 6 to 8 million acre-feet, or 9 to11 percent of the total has been withdrawn.

A wellfield is a group of wells used by a wa-ter provider in an area where the subsurface ge-ology is suitable for pumping. The wells maynot be located close together but might still bereferred to as a wellfield for administrative pur-poses. Tucson Water currently operates fourmajor wellfields – Central, Southside, SantaCruz and Avra Valley. A fifth wellfield is being

developed further north in the Avra Valley, torecover recharged water from the Central AvraValley Storage and Recovery Project. TucsonWater delivered approximately 114,000 acre-feetof groundwater in 1996. Figure 3-1 shows how

17

Chapter 3

IN SEARCH OF

ADEQUATE WATER

SUPPLIES

Most water issues have to do with either water supply or

water quality. In more personal terms these issues have to

do with our need for an adequate supply of good quality

water. This chapter looks at Tucson’s water supplies and our need

for sufficient water resources to support our growing community.

Present resources are described; methods to make present supplies go

further are discussed; and possible strategies for bringing new water

supplies into the basin are described. Chapter 5 discusses how weuse water, and Chapter 6 discusses water quality.

Figure 3-1 Contribution of Tucson Waterwellfields to total groundwater supply.

Source: Tucson Water.

much each wellfield contributes to totalpumping.

The distance from land surface to the wa-ter table is termed “depth to water.” Thepresent depth to water in the Tucson arearanges from less than 50 feet to more than700 feet. In certain parts of the TucsonMountains, it is as much as 900 feet. Depthto water is greatest in the foothills of moun-tain fronts and shallowest in the Altar,Brawley and Cañada del Oro washes and near

Rillito Creek and the Tanque Verde Wash. Inthe Tucson area groundwater generally flowsslowly to the north and northwest, at an aver-age rate of only about several hundred feet peryear, or a foot or two per day. (See Figure 3-2.)

The figure on the inside cover of thisdocument shows changes in groundwater levelssince 1940. Between the 1940s and 1995,groundwater levels declined over 150 feetnorthwest of the Green Valley/Sahuarita area asa result of pumping by copper mines. Water


18

Figure 3-2 Elevation of water table and direction of groundwater flow.

Sources: Arizona Department of Water Resources, Water Resources Research Center.

WHAT IS GROUNDWATER?

Groundwater is water that fills spacesunder ground, between grains of sand orrock or in subterranean cracks. The areawhere groundwater occurs is the “aquifer.”The top level of the aquifer saturated withgroundwater is the “water table.” The mostproductive aquifers consist of water storedin sand and gravel. These areas are typicalof ancient floodplains (alluvium) where wa-ter, rocks and sand were deposited at aboutthe same time. Water and soils flowingfrom mountains over long periods of timecreated some of Tucson’s most productiveaquifers.

Openings between the subterraneanstorage areas must be interconnected forwater to flow freely. Over the years, watermoves slowly downward to the aquifer andalso spreads out, moving generally north-west in the Santa Cruz Valley. At somepoint, the water will reach solid rock or alayer of clay. When such an impermeablelayer is near the surface, water may occuras surface flow or springs. If the water tableis relatively close to the surface, rivers canflow. Excessive pumping from aquiferscauses the water table to recede, and surfaceflow is no longer possible except duringrainy periods. Another impact of pumpingis that grains of sand or rock compact aswater is withdrawn. Percolating water thenis much less likely to refill the spaces, espe-cially at greater depths. Tucson’s water ta-ble has significantly dropped throughoutmost of the region.

levels declined more than 200 feet in parts ofthe Central Wellfield and over 100 feet in theSouthside Wellfield due to pumping by theCity of Tucson. Current declines in the CentralWellfield are averaging up to four to five feetper year.

Water levels have declined over 150 feet inthe southern Avra Valley. The City of Tucsonretired farmland in this area, and water levelshave rebounded at some locations. Water levelshave continued to decline in other parts ofsouthern Avra Valley, in areas where the Tuc-son Water is pumping water for municipal use.

Groundwater levels, however, are no longerdeclining from municipal pumping in thelower part of the Cañada del Oro area, afterdrops of about 50 feet. Water levels thatdropped from agricultural pumping southeastof Marana are now rising, partly because of ef-fluent recharge, increased natural recharge anddecreased agricultural use. Water levels havealso increased along the Santa Cruz River be-cause of above average flood flows since thelate 1970s.

Thus, the broad pattern of steady, re-gion-wide groundwater level declines is seen ata greater level of detail to be a more complexpattern of rising and dropping groundwaterlevels, influenced by local water uses and re-charge, and by the impacts of wet and dryyears.

IMPACTS OF EXCESSIVEGROUNDWATER PUMPING

There are several major impacts associatedwith continued groundwater pumping in ex-cess of the rate of natural recharge. The mostfar-reaching and potentially destructive is landsubsidence and earth fissures. Other impacts in-clude increasing costs of pumping groundwaterand generally decreasing quality of groundwaterpumped from greater depths.

SubsidenceA consequence of water level declines is

land subsidence. According to an Arizona Geo-logical Survey publication “subsidence is thedownward movement or sinking of the earth’ssurface caused by removal of underlying sup-port.” In Arizona, subsidence usually resultsfrom excessive groundwater pumping. As wateris pumped from an aquifer, the water occupy-ing spaces between rock particles is removed,

Chapter 3. In Search of Adequate Water Supplies

19

Figure 3-3 Map of wells and Tucson Water wellfields.

Sources: Pima County, Arizona Department of Water Resources, Tucson Water, Water Resources Research Center.

WHAT’S AN ACRE-FOOT?

An acre-foot is enough water to coveran acre of land to a depth of one foot.An acre-foot contains 325,851 gallons.

and the water level or water table drops. With-out the buoyancy of the groundwater, the parti-cles become more tightly packed together; i.e.,the particles compact and consolidate.Continued pumping of groundwater withoutadequate recharge causes sediments to becomeincreasingly compressed, and the land surfaceto settle or subside. (See Figure 3-4.)

In most cases, subsidence resulting fromgroundwater pumping occurs at about the samerate over large areas and can be difficult to de-tect. However, abrupt changes in conditions be-low the land surface can cause the rate ofsubsidence to vary considerably over a shortdistance. This “differential subsidence” is morelikely to cause damage to houses, commercialbuildings, or infrastructure such as water andsewer lines or roads.

A related phenomenon, an earth fissure is avisible, and sometimes even spectacular mani-festation of land subsidence. Fissures usuallyare noticed first as land cracks or crevices, abreak in the earth’s surface. They can then growconsiderably as water erodes the fissured area.Gullies or trenches may be up to 50 feet deepand 10 feet wide, with the fissure extending

hundreds of feet below the surface. The fissuremay range in length from a few hundred feetto over eight miles. “El Grande” fissure systemis ten miles long and is located in the PicachoBasin, northwest of Tucson. The averagelength of a fissure is measured in hundreds offeet. In the Tucson area fissuring has oc-

curred west of the Tucson Mountains in AvraValley.

Arizona ranks third nationally in land areaaffected by subsidence, after California andTexas. More than 3,000 square miles of thestate have subsided, with hundreds of fissuresoccurring since the 1950s. The occurrence ofsubsidence in south-central Arizona is a majorconcern because it is a core area of the state,with major agricultural and urban centers. ThePhoenix and Tucson metropolitan areas are lo-cated within this area, as well as agriculturalproduction areas within Pinal and Maricopacounties.

Urban areas are especially vulnerable to thedamaging effects of subsidence. Cities are denseareas of population, with large numbers ofbuildings and facilities. Also within urban areasare the varied projects and structures — bridges,highways, electric power lines, undergroundpipes, etc. — that make up the urban infrastruc-ture. Railroads, earthen dams, wastewater treat-ment facilities and canals also are prone todamages from subsidence. Sewer lines, laid atprecise gradients, can have their slopes reducedor even reversed, with serious consequences.Any structure built across the path of a fissurelikely will suffer serious damage. Careful andexpensive construction procedures were workedout to protect the CAP canal from subsidencedamage in certain areas. Despite these precau-tions, the canal was damaged by an earth fis-sure in Pima County in 1988.

The U.S. Geological Survey (USGS) reportsthat since 1940 groundwater levels in CentralArizona have dropped over 220 feet, with Cen-tral Tucson subsiding at least one foot since1950. Meanwhile the rate of subsidence in the


20

RENEWABLE VS.NON-RENEWABLE SUPPLIES

In this report “renewable supply” re-fers to water that is naturally replenished,and “non-renewable supply” refers tostored groundwater. Thus rainfall is re-newable whether it is used directly orwhether it adds to the stored groundwa-ter through recharge.

Figure 3-4 Subsidence near Eloy. Dates onthe pole mark more than 15 feet of subsidence

from groundwater pumping between 1952and 1985. Photo: U.S. Geological Survey.

area is increasing. Satellite images show thatsections of central Tucson are sinking at therate of 2 centimeters or 0.8 inches per year.

USGS monitors water levelchanges and subsidence at 19southern Arizona sites. SomeUSGS sites are in Tucson.

NPA Satellite Mapping is acompany that uses satellite im-ages taken over a period ofyears to plot subsidence. Satel-lite imagery coupled with atechnique called interferometrydetermines the subsidence rate.This procedure was applied toidentify a large subsidence areain central Tucson, centered atthe intersection of East Speed-way and Country Club Road.This marks the spot of thegreatest subsidence activity inthe Tucson area.

USGS models predict levelsof subsidence likely to occur inTucson wellfields. Assumingthat groundwater pumping andnatural recharge rates continueat 1986 levels through 2025,and based on other assumptionsabout the aquifer material beingcompacted, USGS models indi-cate that maximum subsidencecould range from 1.2 to 12 feetin the Central Wellfield by theyear 2025. (See Figure 3-6.) Un-der the same assumptions, sub-sidence in the Santa CruzWellfield could reach up to 4feet by the year 2025. For north-

ern Avra Valley, maximum subsidence potentialis estimated to range from 0.9 to 14.7 feet by

the year 2025, assuming that pumping levelsand natural recharge rates continue at 1970slevels. If subsidence approaches the maximumlevel projected for the year 2025 in the CentralWellfield, the risk of differential subsidence issignificant, especially near downtown Tucson.

Subsidence can be halted by ceasing or lim-iting groundwater withdrawal in an area. Also,under the right conditions, overdraft may be re-duced through artificial recharge, thus slowlydecreasing the danger of further subsidence. Inmost cases, subsidence is termed inelastic be-cause the sinking of the ground is permanent,and recharge would not reverse the process.

Well-injection recharge is likely to be moreeffective than other types of recharge at ensur-ing that water is recharged close to the com-pacting layers. Surface water recharge projectsmay be effective at restoring the water table. Inmost cases, however, once subsidence occurs,the water storage capacity of the aquifer is per-manently reduced. In some cases, recharge pro-jects may even worsen subsidence, as the weightof the water applied at the surface compacts theunderlying aquifer materials even more.

Increased Pumping CostIn those areas with the most pumping, wa-

ter level declines may lead to lower productivitybecause as the water is pumped from greaterdepths, the aquifer materials become morecompacted and hold less water. For example,well yields in the Santa Cruz and SouthsideWellfields have decreased over the years. Aver-age yield for wells in the Santa Cruz Wellfieldin 1992 was less than a third of what it was in1958. Average yield in the Southside Wellfield


21

Figure 3-5 A fissure can appear as a deep gash in the earth.The above fissure is southeast of Phoenix.

Photo: Ray Harris.

in 1992 was about half of what it was in thelate 1960s. Further decreases are expected forboth wellfields, if pumping continues at cur-rent rates and groundwater level declines con-tinue. If the same amount of water is to bepumped, loss of productivity in wells meanshigher pumping costs for water utilities. Costscan further increase if older, shallower wellsneed to be replaced with deeper ones.

Decreased Water QualityThe quality of water pumped also is ex-

pected to generally decline as it is pumpedfrom greater depths. The total dissolved solids(TDS) of Tucson area groundwater currentlyaverages about 300 parts per million, althoughTDS measurements in some areas are muchhigher. An increase in TDS shortens the usefullife of many water-using appliances and waterpipes because of accelerated corrosion.

RENEWABLE SUPPLIES

Central Arizona Project WaterCAP water is the largest renewable water

supply in the Tucson area. CAP water is liftedsome 2,900 feet through 14 pumping plantsand transported through open canals, siphonsand pipes a distance of 336 miles from the Col-orado River at Lake Havasu through the Phoe-nix area and then south to Pima County. CAPwas designed to deliver up to 1.5 millionacre-feet of water annually to central Arizona.

Over 215,000 acre-feet of CAP water are al-located to entities in the Tucson area, with ap-proximately 38,300 acre-feet subcontracted toIndian users. Appendix B lists the CAP alloca-

tions of all the local water providers. Addi-tional CAP water that is available to the Ari-zona Water Banking Authority and the CentralArizona Groundwater Replenishment Districtcould be recharged in the Tucson area.

The City of Tucson has the largest alloca-tion of CAP water in the state: 138,920acre-feet. This is Tucson’s total allocation afterthe recent agreement between the City of Tuc-son and the Metropolitan Domestic Water Im-

provement District (Metro Water) that transfers9,500 acre-feet of Tucson’s allocation to MetroWater and Oro Valley. In the early 1990s, theCity of Tucson intended to use increasingamounts of its allocation by directly deliveringtreated CAP water to its customers and to othermunicipal water providers on the northwestside, and recharging additional amounts forlater use. CAP water was first delivered to ap-proximately 60 percent of Tucson Water cus-


22

Figure 3-6 Maximum potential subsidence in feet.

Sources: United States Geological Survey, Arizona Department Water Resources.

tomers starting in 1992. Direct deliveries weresuspended for some of those customers in Sep-tember 1993 and halted indefinitely for all cus-tomers in November 1994, after problems arosewith the taste, odor and color of the water, andpipes and water-using appliances were damaged.

The aborted effort to introduce CAP watercaused city residents to be wary of the resource,and in 1995 they approved the Water Con-sumer Protection Act. This voter initiative pro-hibits direct delivery and injection recharge ofCAP water unless stringent water quality crite-ria are met. As a result of the initiative, the cityhas switched its CAP use strategy from mostlydirect use to recharge. After declining from apeak of approximately 52,000 acre-feet in 1993to 10,200 acre-feet in 1995, CAP water deliver-ies to the Tucson Active Management Area(TAMA) have grown to 19,800 acre-feet in 1996and 34,200 acre-feet in 1997. Almost all of thewater was delivered to direct recharge projectsor Groundwater Savings Facilities (See sectionon recharge, below).

Some municipal providers with CAP con-tracts, such as those in the Green Valley area,cannot use their allocations directly because thecanal does not reach them. To better servicethem, a group of water users in the UpperSanta Cruz basin studied the possibility of ex-tending the CAP canal from its current endpoint near Interstate 19 and Pima Mine Roadsouth of Tucson to the Green Valley/Sahuaritaarea. In a 1998 study, the group identified pos-sible alignments for the canal and estimatedcosts. Other municipal providers who cannotuse their allocations directly plan to rechargetheir CAP water to offset some of their ground-water pumping.

Treated EffluentTreated effluent is wa-

ter that has been used inhomes and businesses andthen collected by the sew-age system and treated ata wastewater treatmentplant, for various wateruses. Some 85 to 90 per-cent of households in theTucson metropolitan areaare connected to the cen-tral sewage system. Efflu-ent is considered arenewable supply becauseit extends our storedgroundwater supply. Gen-erally as population in-creases, so does thesupply of effluent.

Total treated effluent production fromwastewater treatment plants in the TucsonAMA (TAMA) was 70,100 acre-feet in 1996, orapproximately 63 million gallons per day(mgd). Almost all the effluent came from theIna and Roger road treatment plants. Nineother small treatment facilities are located inPima County, and an estimated 11 percent ofsingle family residences have septic tanks. Totaleffluent flows in Pima County are projected toreach 103 mgd, or 115,760 acre-feet, by the year2025.

Wastewater delivered to the Ina and Rogerroad treatment plants undergoes primary andsecondary treatment processes at treatment fa-cilities to meet state and EPA water qualitystandards. Of the approximately 69,400

acre-feet of secondary-treated effluent producedat these plants in 1995, approximately 4 per-cent was delivered directly to farms and an-other 2 percent was delivered directly to turffacilities such as golf courses. Another 13 per-cent was sent to Tucson Water’s reclaimed wa-ter facilities, located next to the Roger RoadWastewater Treatment Facility for additionaltreatment involving filtration through sand fil-ters or soil and additional disinfection. Re-claimed water then is delivered for use or isrecharged at the Sweetwater Underground Stor-age and Recovery Facility, to be pumped outwhen needed to meet peak irrigation demandsduring summer. (See Chapter 5 for more infor-mation on the use of effluent.)

The remaining 84 percent of the effluent isreleased into the Santa Cruz River channel. Ap-proximately 96 percent of released discharges


23

Figure 3-7 Tanks from a Pima County wastewater treatment plant.Photo: Barbara Tellman.

eventually infiltrates the river channel to theunderlying aquifer within TAMA. The remain-ing 4 percent evaporates or is used by riparianvegetation.

The Regional Effluent Planning Partner-ship has listed 20 effluent projects and poten-tial alternatives as of January 1999 (SeeAppendix B). Of these 20 projects, three pres-ently exist, seven are in the process of beingbuilt and ten are proposed for the future. Two

of the proposed projects would create rechargecredits for the existing discharge to the SantaCruz River. If these projects are approved, thestate would grant credits for 50 percent of theamount of effluent recharged. These creditscould be used to allow groundwater pumpingelsewhere in the TAMA, partially nullifying thecontribution of the existing effluent dischargestowards safe yield calculations for TAMA. Anassessment also is currently being conducted to

determine potential impacts of any changes ineffluent discharge on the riparian area down-stream of the wastewater treatment plants.

At least seven constraints may limit full useof effluent. None of these constraints are insur-mountable barriers; yet they must be taken intoconsideration when making plans for dealingwith effluent. They include:

• A water rights settlement with theTohono O’odham Nation obligates up to28,200 acre-feet of effluent produced at metro-politan area wastewater treatment facilities tothe U.S. Secretary of the Interior for the IndianNation.

• Of the effluent remaining after the Secre-tary’s share is subtracted, the City of Tucsonhas control of about 90 percent of the effluentproduced at metropolitan area wastewater treat-ment facilities, under a 1979 intergovernmentalagreement. Pima County processes all of thewastewater but controls 10 percent

• ADWR has complex rules for how mucheffluent use or recharge counts toward meetingAssured Water Supply Rules. Recharge of efflu-ent through a constructed facility, for example,counts more than “managed” recharge of efflu-ent in a streambed, while direct reuse has thehighest value.

• ADEQ and EPA have strict water qualityrules for discharge to streambeds and for vari-ous uses of effluent. As wastewater treatmentplant permit conditions have become stricter inrecent years, Pima County has urged that stan-dards be relaxed or that streambed releases bediscontinued.

• The cost of building distribution systemsfor use can be high, especially for golf coursesor other facilities far from the treatment plant


24

Figure 3-8 Wastewater treatment facilities and distribution system.

Sources: Pima County Technical Services, Pima County Wastewater.

and usually requiring uphill pumping. Tucsoncurrently sells effluent for $475 per acre-foot,which is about$100 per acre-foot less than thefull cost of treating and delivering it. PimaCounty sells effluent for a fraction of that costat $11, but does not provide tertiary treatmentand delivers effluent to customers downhill,not too distant from the treatment plant.

• A 1989 Arizona Supreme Court decision(Arizona Public Service v. John F. Long) leftregulation of effluent unclear, and the ArizonaLegislature has never dealt fully with the mat-ter. Effluent, however, is regulated with regardsto its water quality.

• Although effluent is treated, it still con-tains some contaminants that can affectgroundwater. These include nitrates which havebeen found in groundwater in the Marana areaand are probably the result of both agriculturalactivity and effluent. Excess nitrates can causeserious problems for infants.

AUGMENTING THE WATERSUPPLY — RECHARGE

In Tucson — in fact, in most of the heavilypopulated areas of Arizona — depletion of theaquifer is a problem and is the underlying con-cern for much public policy. Recharge is an im-portant tool in managing groundwater levels inthe Tucson area and has attracted much atten-tion from government agencies, university re-searchers, concerned citizens and others.Passage of the Water Consumer Protection Actin 1995, which directed the City of Tucson touse its CAP water allotment for recharge or totrade with area farms and mines instead of di-

rect delivery to homes, has increased attentionpaid to development of recharge projects in thearea.

Recharge generally refers to the addition ofwater to groundwater already in the aquifer. Inorder to recharge the aquifer, water usuallymust first infiltrate the soil or ground surfaceand then percolate though the unsaturatedzone of the aquifer (referred to as the vadosezone) to reach the water table. The water tabledefines the top part of the aquifer which is sat-urated with groundwater. An important distinc-tion exists between infiltration and recharge.Infiltration is entry of water into the soil andthe movement of water from the soil into thevadose zone. Recharge is addition of water tothe part of the aquifer which is saturated withgroundwater and can be pumped.

Recharge of an aquifer occurs in threeways: natural recharge resulting from precipita-tion and runoff; incidental recharge from waterthat seeps into the ground after various humanuses, such as irrigation; and artificial rechargeby constructed or managed projects designed toput water in the aquifer. These three types of re-charge help maintain a balance of water useand supply.

Natural RechargeNatural recharge is the addition of precipi-

tation and streamflows to groundwater suppliesin the aquifer. Water from precipitation andrunoff infiltrates mainly along mountainfronts and in stream channels and also as directunderflow from joints and other openings inrocks. Snowmelt and mountain precipitationoften infiltrates at the foot of mountain ranges.

Mountain-front recharge in TAMA averagesabout 39,000 acre-feet annually. Stream channelrecharge in the Tucson area occurs as a resultof infrequent, but occasionally large streamflow events. Some of the water that flows instreams after heavy rains infiltrates thestreambed to recharge the groundwater aquifer.Total stream channel recharge in TAMA aver-ages approximately 38,000 acre-feet per year.(See Chapter 4 for more information.)

Underground flow of groundwater also isincluded in calculating natural recharge to anarea. Groundwater generally moves slowly (at arate of a couple hundred feet per year) to thenorth and northwest in the Tucson area. Onaverage approximately 9,000 acre-feet per yearof groundwater flows underground into TAMAfrom the south every year and about 25,000acre-feet per year leaves TAMA by flowing un-derground to the north.

Incidental RechargeIncidental recharge is water that reaches the

water table after human use. The amount of in-cidental recharge in TAMA depends mostly onthe extent and water use efficiency of certainhuman activities, such as irrigated agriculture,mining and the discharge of effluent intostream channels. ADWR has estimated that an-nual incidental recharge in TAMA totals about81,000 acre-feet, based on water use levels pro-jected for the year 2000. Most is effluent dis-charged by the two large wastewater treatmentplants.


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Artificial RechargeArtificial recharge of either CAP water or

effluent is an important method of utilizing re-newable supplies in TAMA. Artificial ground-water recharge generally involves constructingfacilities to control the movement and rate ofinfiltration. The following discusses artificialrecharge as a way of replenishing the aquifer.Using artificial recharge as a water treatmentmethod is discussed in Chapter 6.

The State of Arizona’s Underground WaterStorage, Savings and Replenishment Programallows two types of recharge facilities: Under-ground Storage Facilities (USFs) and Ground-water Savings Facilities (GSFs). USFs, or directrecharge facilities, can include “constructed”projects, such as spreading basins, structuresplaced in a stream channel to increase percola-tion into the stream bed, or injection wells, aswell as “managed” projects, where water is ap-plied to stream channels without constructedfacilities (See side bar for discussion of thetypes of direct recharge facilities). In the case ofconstructed projects, the rate of application ofwater is regulated through facility design andoperating procedures to control the rate atwhich water reaches the aquifer and to ensurethat quality is not impaired. Through GSFs, or“in lieu” recharge facilities, incentives are pro-vided to encourage farms or other entities touse renewable supplies such as CAP water in-stead of groundwater. (See Chapter 5 for a dis-cussion of CAP water use by Tucson area farmsthrough GSFs, and Chapter 7 for additional ex-planation of GSFs and USFs.)

A water storage permit holder may chooseto recover water in the same calendar year (an-

nual storage and recovery) or to accumulatelong-term storage credits. ADWR maintains along-term storage credit account for eachstorer. In most cases involving direct rechargeof CAP water, storers get credits for 95 percentof the volume of water stored minus evapora-tion. The state requires the other five percent toremain in the aquifer as permanent recharge.Municipal providers can use long-term storagecredits to help meet their Assured Water Sup-ply requirements and to help prove the physi-cal availability of an assured water supply.

Little of the CAP water recharged inTAMA so far has been pumped for use, al-though the City of Tuc-son is constructing awellfield to allow recov-ery of water stored at theCentral Avra Valley Stor-age and Recovery Project(CAVSARP) in the nearfuture. Generally, recov-ery of recharged water ispermitted if it is recov-ered in the area wherethe water was originallystored, or in an area towhich it migrated afterstorage. Recovery of wa-ter outside this “area ofimpact” is permitted un-der certain conditions toensure that recovery ofwater does not occur inareas with substantiallydeclining groundwaterlevels.

Figure 3-11 is a map of existing and pro-posed direct recharge facilities in TAMA. Fourdirect recharge facilities are currently operatingin TAMA. These include CAVSARP, PimaMine Road Recharge Project, Avra Valley Re-charge Project and Sweetwater UndergroundStorage and Recovery Project. All of these pro-jects utilize off-channel spreading basins to re-charge CAP water, except the Sweetwaterfacility, which uses basins to recharge reclaimedeffluent.

Figure 3-10 shows the amount of waterstored at direct recharge facilities over time.The amount of water stored at Tucson area pro-


26

Figure 3-9 The Pima Mine Road recharge basins.Photo: Central Arizona Water Conservation District.

jects is small compared to the total renewablesupplies available. Not including CAP waterused at groundwater savings facilities, about7,800 acre-feet of CAP water was recharged inTAMA in 1997, compared to approximately215,000 acre-feet of CAP water available undersub-contract to entities in TAMA.

Direct injection is the most certain methodof recharge because water can be directed to aspecific location within an aquifer. For this rea-son, local recharge experts believe that direct in-jection may be the most effective tool inmitigating subsidence. With direct injection,water can be added as close as possible to thelayers of the aquifer that are being compacted.The extent to which subsidence can be limitedwith this method, however, is uncertain, de-pending in part on the type of aquifer materi-als. Tucson Water stored approximately 4,000acre-feet of CAP water using two pilot injectionwells in 1993 and 1994. The Water Consumer

Protection Act, however, allows direct injectiononly if the water meets or exceeds the waterquality of Avra Valley groundwater in terms ofhardness, salinity and dissolved organic materi-als and is free of disinfection by-products.Costs of treating CAP water to the Avra Valleygroundwater standards would be prohibitivelyexpensive. Entities in the Tucson area otherthan Tucson Water are not bound by WCPAbut have not attempted direct injection.

New direct recharge projects are beingplanned. (See Figure 3-11.) A facility permit has

been issued for the Lower Santa Cruz Replen-ishment Project, which is projected to have acapacity of 12,000 to 13,000 acre-feet in its firstphase. The facility will be located along theSanta Cruz River in northern Avra Valley. Theproposed Cañada del Oro Recharge Projectcould add another 30,000 acre-feet of direct re-charge capacity in northwest Tucson near theTown of Oro Valley. A study of the technicalfeasibility of the project is currently being con-ducted. Total direct recharge capacity onnon-Indian land in TAMA is projected to be


27

Figure 3-11 Existing and proposed direct recharge projects.


Figure 3-10 CAP water deliveries to directrecharge projects in the Tucson AMA*.

Source: Central Arizona Water Conservation District.

49,000 acre-feet in the year 2000, possibly risingto 131,000 by the year 2007 with the additionof a full-scale Lower Santa Cruz ReplenishmentProject, the Cañada del Oro Project and expan-sion of existing projects to full-scale. Proposedrecharge projects on Indian land could add upto an additional 41,000 acre-feet of direct re-charge capacity by 2007.

Recharging the Central WellfieldThe highest rate of groundwater decline in

TAMA is occurring in the Central Wellfield,and USGS models project that subsidence inthat part of TAMA could greatly increase. Arti-ficial recharge has been suggested as one way of

stopping declines of groundwater levels in theCentral Wellfield, and the WCPA directs theCity of Tucson to recharge the CentralWellfield. Although artificial recharge couldhelp reduce groundwater level declines in theCentral Wellfield, determining the best methodof recharging the area is difficult, and recharg-ing large amounts of water requires extensivefacilities. With current withdrawals from theCentral Wellfield ranging from 60,000 to70,000 acre-feet per year and natural rechargeestimated at 17,000 acre-feet per year, 43,000 to53,000 acre-feet per year of recharge would berequired to stop the decline of groundwater lev-els. This is a great deal of water to recharge ev-ery year in central Tucson.

One possible way of recharging the CentralWellfield is by releasing CAP water into theRillito Creek, Tanque Verde Creek and thePantano Wash. These stream channels generallyoverlap the Central Wellfield, although most oftheir flows are to the north-northwest, not to-ward the Central Wellfield. The high infiltra-tion rates in local stream channels would seemto support the premise that large amounts ofCAP water could be successfully recharged us-ing such channels to replenish the CentralWellfield. The long-term recharge rate, how-ever, often differs from the short-term surfaceinfiltration rate. The short-term rate is the rateat which water enters the coarse-grained chan-nel alluvium. Water generally infiltrates this al-luvium very easily. The long-term recharge rateis the rate at which water actually reaches theaquifer, and is determined by basin fill depositscloser to the aquifer. Because these deposits areless permeable than the recently deposited allu-vium near the surface, the long-term recharge


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TYPES OF ARTIFICIAL RECHARGE

In-Channel Artificial RechargeArtificial recharge facilities operate either in-channel or off-channel. In-channel con-

structed facilities are recharge facilities built into a river or stream bed to retain water whileit infiltrates through the stream bed into the underlying aquifer. These structures includeinflatable dams, gated structures, levees and basins, or other devices designed to impedewater flow. Levees are the least expensive of these alternatives, but are the most subject todamage from flood flows. Also operating in-channel, managed facilities allow water to infil-trate the stream channel without the aid of structures to impede flow.

Off-Channel Artificial RechargeOff-channel artificial recharge facilities include shallow spreading basins. These basins

are dug up to 20 feet deep to reach more permeable layers and are usually constructedwith earthen berm walls to hold water in place. During operation, the depth of water usu-ally does not exceed five feet. Basins are operated on a wet/dry cycle to allow periodicscrapings or other techniques to maintain high infiltration rates.

Deep basins or pits also can be used for off-channel recharge. These facilities are usuallyconverted from other uses, such as gravel pits. During operation, water levels up to about10 feet are usually maintained. Operating costs are usually low, since basins are drainedand maintained only once every year or two. Infiltration rates, however, are usually lowdue to build up of organic matter.

Also operating off-channel, injection wells are usually existing water extraction wellsconverted to allow injection of water directly into the aquifer. Water injected must nor-mally meet drinking water standards (Maximum Contaminant Levels). The Water Con-sumer Protection Act effectively prohibits the City of Tucson from using injection wellsunless the water injected is treated to the same standards as Avra Valley groundwater andis free of disinfection byproducts.

rate is lower than the short-term infiltrationrate. If water were released in the stream chan-nel over a long period of time (perhaps greaterthan a year), water would mound up in thechannel alluvium. Water then would eventu-ally rise to the stream channel, and water re-leased at the surface would infiltrate at thelong-term rate, or be rejected as subflow or sur-face flow.

A panel of hydrologists and other technicalexperts formed by ADWR in 1996 estimatedthe maximum long-term average annual vol-ume of artificial recharge possible in streamchannels generally overlying the CentralWellfield (Rillito Creek, Tanque Verde Creekand the Pantano Wash). The panel concluded

that the maximumlong-term averageannual volumethat could be ef-fectively infiltratedthrough thosechannels is ap-proximately29,000 acre-feet.When the volumeof natural rechargeis considered, totalmaximum poten-tial average annualvolume of artifi-cial and natural re-charge in thestream channels isapproximately50,000 acre-feetper year. Some ofthese stream

reaches have landfills, however, containing con-taminants that could pollute recharged water.After excluding stream reaches with knownlandfills, the maximum long-term average an-nual volume of artificial and natural rechargewould be about 27,000 acre-feet, or only 38 to44 percent of present annual withdrawals fromthe Central Wellfield.

Recharge experts also have pointed outthat some of the water which infiltrates thestream channels generally overlying the CentralWellfield may not reach the underlying aquifer.This is because some of the water applied to lo-cal stream channels would likely move down-stream as subsurface groundwater flow justbeneath the streambed instead of recharging

the Central Wellfield. This subflow wouldtravel downgradient to the alluvium under-neath the Santa Cruz River after its confluencewith the Rillito Creek and move towards PinalCounty. Any of this subflow eventually reach-ing the aquifer would be too far from the Cen-tral Wellfield to benefit it. Preliminary resultsof attempts to date groundwater based uponisotopic analyses indicate that groundwater lo-cated a couple miles south of the Rillito ishundreds or thousands of years old. This sug-gests that limited recharge of the CentralWellfield is occurring.

The City of Tucson is planning to addresswater decline problems in the Central Wellfieldby pumping instead from CAVSARP. The pro-jected full-scale capacity of CAVSARP is 60,000acre-feet per year. If enough water is recoveredannually from CAVSARP to offset current an-nual pumping in the Central Wellfield, mostof the Central Wellfield groundwater pumpscould be shut off. Groundwater level declinescould then be stopped or slowly reversed withthe help of natural recharge. Water recoveredfrom CAVSARP would be sent though theHayden-Udall (CAP) Treatment Facility beforebeing delivered to homes.

USGS has begun a project to study the lo-cation and timing of recharge in the 12-milestretch of the Rillito Creek from CraycroftRoad to the Santa Cruz River. Approximately$635,000 is budgeted to collect the needed dataand build groundwater models to investigatevarious recharge scenarios. This study is ex-pected to greatly improve assessment of the fea-sibility of artificial recharge in the RillitoCreek to benefit the Central Wellfield. (Formore information see Chapter 4.)


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Figure 3-12 Movement of recharged water through the aquifer.

OTHER STRATEGIES

In response to our ongoing water worries,various strategies have been proposed to in-crease regional water supplies of our region.Options for increasing water supplies in Tuc-son, however, are limited. Using CAP water iscurrently Tucson’s only major strategy for in-creasing water supplies. Whether it is used di-rectly in municipal systems or by agriculture ormines, or whether it is recharged for later use,CAP water can add considerably to the basinsupply. Use of effluent does not bring new wa-ter into the basin, but does help prolong the

water supplies by reducing the need to usestored groundwater.

Following is a discussion of various strate-gies for increasing water supplies in the TucsonBasin. A few obviously require a large-scale in-vestment of funds and other resources; otherscan be done by individuals in their homes andcommunities. A few appear doable; others seemfar-fetched.

Import Water FromOutside the Basin

CAP has not been the only project de-signed to import water from outside the basin

to increaseTucson’s watersupplies. Itsdistinction isthat it was theonly such pro-ject to bebuilt. Over theyears, otherstrategies havebeen proposedto bring waterhere from else-where. Onescheme of-fered in the1970s wouldhave broughtwater fromthe Yukon,through Can-ada to theGreat Lakes

and ultimately to the Southwest. Another he-roic scheme would have imported water fromthe Pacific Northwest to California and Ari-zona. Both strategies were found to be exces-sively costly, not to mention beingunacceptable to people in the Northwest andCanada.

The City of Tucson tried a much less ambi-tious scheme in the 1960s when it purchasedland with water rights north of Benson alongthe San Pedro River, with the intent of build-ing a pipeline to Tucson. A lack of funds and aquestionable supply of water, coupled with op-position from residents, stopped this project,and Tucson sold the land. Another effort tocapture San Pedro water was the CharlestonDam, originally part of the CAP system. This,too, was defeated when Cochise County resi-dents opposed the idea.

Other ideas for obtaining additional waterinclude desalinating seawater, either along theGulf of California or near San Diego and pip-ing it to Arizona. A fanciful proposal in the1980s suggested towing icebergs from Antarc-tica to the California coast and piping themelted water to Arizona. Neither of these pro-jects appeared feasible or cost-effective.

Capture FloodwaterTo many people, allowing flood water to

drain out of the basin represents a lost re-source. Heavy rain showers occur occasionallyin the desert, filling arroyos and river beds withabundant and vigorously flowing water. Cap-turing more of this flow could augment oursupplies, whether used directly or recharged.With Tucson riverbeds seeming to offer prom-


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Figure 3-13 The Pacific Northwest Water Plan of the 1970s proposed bringingwater from Canada to a wide region including Arizona.

Photo: Barbara Tellman.

ising sites, Tucson water history during thetwentieth century includes various references toplans for capturing runoff. At times, suitablelocations to capture and control mountain run-off have been proposed. Tucsonans looked tothe dams along the Salt River as models, butthe Santa Cruz River and its tributaries offeredno comparable sites suitable for large storagedams. Studies are underway to determinewhether other methods such as inflatable damscan be effective. (See Chapter 4 for a discussionof this topic.)

Vegetation ManagementIn the 1960s and 1970s, removing vegeta-

tion along watersheds was considered a promis-ing way to increase water supplies for cities.This strategy was based on the fact that vegeta-tion uses water that otherwise could be put tohuman uses. Some experiments were con-ducted; chains, cables and chemicals were usedto remove chaparral and piñon-juniper forests.Ponderosa and mixed conifer forests were har-vested. While initial results often showed an in-crease in streamflow, long-terms results werenot conclusive. Grasses often took over areasdenuded of trees, using about as much water asdid the trees. Where vegetation did not have achance to regrow before heavy rains, erosiontook away topsoil.

Some people have advocated removing cot-tonwoods along rivers such as the San Pedrobecause of the water they use, but the resultswould be mixed at best. Some gains would beoffset by the loss of shade to cool the water andreduce evaporation and by the loss of a root

system to help hold soil in place. The increasedimportance that people place on riparian vege-tation for habitat and recreation further advisescaution when considering vegetation manage-ment practices. This approach to increasing wa-ter supplies has generally fallen out of favor inArizona.

Weather ModificationAdvocates of weather modification look to

the clouds as a source of water to augment cur-rent supplies. Arizona’s interest in weathermodification evolved over time, from earlycloud seeding experiments to the adoption ofsophisticated computer modeling techniquesthat simulate climatological phenomena andtest weather modification premises. The evolu-tion reflects a change in attitudes, from an op-timistic expectation of immediate results to amore cautious, even skeptical regard about thepotential of weather modification.

Clouds consist of small water droplets that,despite below-freezing temperatures, remain liq-uid. The water’s purity and the lack of foreignparticles in the atmosphere prevent the dropletsfrom freezing. These “supercooled droplets”form supercooled clouds. As temperatures de-crease, the droplets form ice crystals aroundsmall atmospheric particles such as dust. Cloudseeding introduces additional particles or nu-clei into the atmosphere, causing more ice crys-tals to form. Silver iodide compounds or dryice are the usual cloud seeding agents. Aircraftor ground-based generators introduce theagents into the atmosphere. The ice particlesgrow and attract nearby water vapor and drop-

lets. The enlarged ice particles eventually fall assnow. Clouds which form over mountainousareas are preferable for seeding because they lastlonger, and weather modification experimentscan be more readily arranged.

A number of legal, social and environmen-tal issues would have to be resolved beforeweather modification could be used on a largescale, even if it proves to be effective. Who is li-able for damages from floods or other weatherevents resulting from weather modification?How are the rights of those who want rain tobe reconciled with the rights of those who pre-fer sunshine? What if precipitation increases ina basin in which cloud seeding occurred but de-creased during the same period in another ba-sin? Has the latter basin been wrongfullydeprived of its precipitation?

And there are other questions: How is itdetermined that precipitation was in fact the re-sult of weather modification? How is theamount of new water to be quantified forcredit and distribution? On what basis is thenew water induced by weather modification tobe allocated among water users? How can thosewho pay for the weather modification be en-sured that they will in fact receive their share ofthe new water?

Environmental problems also may arise.For example, increased precipitation mightmean increased weed growth, and a heaviersnowpack could disrupt the winter food habitatof large mammals. Concern has also been ex-pressed about the effects of introducing artifi-cial ice-crystal nuclei (e.g. silver iodide, dry iceand liquid propane) into the atmosphere. Envi-ronmental studies are obviously needed to de-termine the effects of cloud seeding.


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STRATEGIES FORINDIVIDUALS

Graywater reuse and water harvesting canbe effective ways for individuals to decreasetheir use of groundwater and thus lower theirwater bill. Both strategies, however, probablydo not contribute very much to the overall wa-ter supply picture in the basin. In areas con-nected to the central sewage system, use ofgraywater reduces the amount of effluent pro-duced and consequently the amount availablefor reuse or recharge. Water harvesting also re-duces the need to pump groundwater and mayhelp relieve flooding problems. At Casa delAgua, a water conservation demonstrationhouse that was supported by the University ofArizona, Tucson Water and ADWR, UA re-searchers tested and evaluated various water sav-ing devices and strategies, including graywateruse and water harvesting.

Use of GraywaterGraywater is water from the bath, shower,

washing machine or bathroom or kitchen sinksin homes. Graywater can supply most, if not allthe irrigation needs of a domestic dwellinglandscaped with vegetation of a semiarid re-gion. Along with its use in outside irrigation,graywater can be used in some situations fortoilet flushing. Metro Water, a utility servingnorthwest Tucson, recently conducted a surveythat found nine percent of its customers usesome portion of their graywater.

Graywater systems vary from simplelow-cost systems to highly complex and costlyunits. The technology involved in such systems

ranges from the sophisticated to the crude,from engineered systems with filters andpumps to a washing machine draining directlyonto oleander bushes.

A permit is technically required to install agraywater system although few people bother.Although ADEQ regulates graywater use in thestate, the agency allows counties to issue per-mits. Any request that involves an exception towhat is allowed in the regulations, however,must go directly to ADEQ for consideration.Some observers believe this splitting of regula-tory authority for graywater use adds unduecomplicates the process of obtaining a permit.

The main concern of regulations is thatgraywater use will result in water quality prob-lems and pose a threat to public health. Regula-tions prohibit graywater systems from beingconnected to potable water systems and do notallow surface applications of graywater. Insteadgraywater must be released below the surface, asunderground landscape irrigation, to preventhuman contact with it. Many advocates claimthe regulations are needlessly complex, and theexpense is a deterrent to graywater use.

Despite regulatory requirements estimatesindicate that there are several thousandgraywater systems in the metropolitan area, andvirtually none are permitted. Some residentsmerely drain their washing machines to watertheir shrubs or trees.

Some researchers question whethergraywater really poses a significant health risk.If the health risks are not as high as some fear,graywater might gain more acceptance as a wa-ter source, and regulations could be eased.

With an ADWR TAMA Conservation As-sistance Grant, the Water Conservation Alli-

ance of Southern Arizona (Water CASA) is con-ducting a study to determine what health risks,if any, result from the low-tech methods ofgraywater use now occurring. Water CASA is inthe process of analyzing several “wildcatgraywater systems,” to accurately analyze andevaluate their water quality, soil chemistry andsystem design. The intent of the study is toraise public awareness, provide information notavailable elsewhere regarding graywater quality


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Figure 3-14 Cistern installed as part of agraywater reuse system. Photo: Val Little.

and its effect on soil, collect data on actual,feasible residential graywater system designand determine the potential graywater has toincrease water use efficiency.

Water HarvestingRainwater harvesting is collecting rainfall

to meet water needs. A rainwater harvestingsystem concentrates and collects rain fallingon house roofs and grounds for direct useand storage.

Water is collected or harvested from con-crete patios, driveways and other paved areas.Also harvested is the flow from the roof andfrom catchments such as gutters. Houses canbe designed to maximize the amount ofcatchment area, thereby increasing rainwaterharvesting possibilities. For example, at Casadel Agua, 600 square feet of additional catch-ment area was added to the porch and green-house roof to maximize runoff. Thisadditional surface increased the amount ofcollected annual rainfall by more than 3,700gallons. Downspouts are located about every20 feet along the gutter, instead of the morecommon 40 feet. This ensured that heavyrains were not likely to overflow the gutterand instead would flow to catchments.

Collected and stored rainwater can beused for evaporative cooling, toilet flushing,car washing, chlorinated swimming pools,and surface irrigation, especially in food gar-dens. In the United States harvested rainfallmostly is used for irrigation, with limitedother domestic uses. At Casa del Agua, wherethe landscape was almost entirely irrigated by graywater, rainwater primarily was used in the

evaporative cooler, with a limited amount used

for toilet flushing. Casa del Agua’s rainwaterstorage capacity was about 8,000 gallons.

Rainwater harvesting systems vary fromthe simple and inexpensive to the complexand very costly. Directing rainfall to plants lo-cated at contoured low points is a very simplerainwater harvesting system. No rain escapesproperty boundaries. More complex rainwaterharvesting systems include water storage.

Rainwater harvesting is an everyman’s wa-ter augmentation method. Any container capa-ble of holding rain dripping from roof orpatio can be a rainwater harvesting system, butmay also breed mosquitoes unless kept cov-ered. A plastic garbage barrel is sufficient.Sturdier and more elegant containers create amore pleasing effect and some are built usingbackyard technology, such as small ferro ce-ment tanks collecting water at the base ofdown spouts. The least expensive rainwaterstorage system uses an above-ground swim-ming pool, with a lid or cover to reduce evap-oration. Rainwater then can be stored forabout .07 cents per gallon.

Harvested rain raises some water qualityconcerns. Rain in certain urban areas may con-tain various impurities absorbed from the at-mosphere, including arsenic and lead. Certaindesert conditions also can cause rainwaterquality concerns. Desert rain is infrequent and,therefore, bird droppings, dust and other im-purities accumulate between rain events. Theythen occur in high concentrations in runoffwhen it does rain. As a result, the quality ofharvested rainfall needs frequent monitoringespecially if used for potable uses. To confront

these problems some systems reject the initialrooftop runoff.


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Figure 3-15 A do-it-yourself water harvestingsystem collects rain from roof for use to irrigate a

home garden. Photo: Barbara Tellman.

FLOODING, THENAND NOW

What is a flood? According to Webster’sdictionary, a flood occurs when wateroverflows onto normally dry land. In

this arid region the term often is used to de-scribe a situation when an unusual amount ofwater flows in usually dry rivers, whether ornot it overflows the banks. In Arizona an un-usual amount of water flowing in a river withsufficient force to erode its banks is almost in-variably referred to as a flood.

Floods provide both benefits and prob-lems. Floods can be beneficial when they re-charge groundwater, but the same flow also candamage buildings and roads, erode land, andcarry pollutants that may reach the groundwa-ter.

Years of bountiful rain and snow alternatewith years of little precipitation. Heavy riverflows occur occasionally and are essential forthe growth of riparian vegetation. During floodyears new cottonwood seedlings sprout andtake hold. Traditional farming took advantage

of the summer rainy season when water over-flowed river banks bringing both moisture andnutrients to the soils. River flows replenishedthe groundwater table that remained near thesurface. The water table was sufficiently highalong most of the Santa Cruz River, from SanXavier to the Cañada del Oro,that cottonwood forests thrived.Such forests also were locatedalong parts of the Rillito Creek,Tanque Verde Wash andPantano Wash. A giant mes-quite bosque flourished southof San Xavier.

Changed river conditionshave destroyed much of this ri-parian habitat, and developingnew riparian habitat would be adifficult challenge, even usingCAP water and effluent. Someeven argue that conditions havedeteriorated to the point thatmany riparian areas are beyondrestoration. Construction alongriverbanks and flood control

structures have radically changed natural riverconditions. Instead of meandering and spread-ing out onto floodplains to benefit riparianvegetation, floods now often are containedwithin deep channels.

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Chapter 4

COPING WITH

FLOODWATER

Chapter Four discusses floodwater and its contribution to naturaland artificial streambed recharge. A heavy rain can cause problems butalso is an important part of the renewable water supply picture. Sincerivers in the area are very different than they were 150 years ago, floodsand natural recharge occur differently now than in the past. Increasedurbanization, use of flood control structures, natural recharge and artifi-cial recharge are interrelated issues that need careful consideration. Wa-ter quality problems can arise when urban runoff carries variouspollutants from paved areas to riverbeds; some of the runoff could thenenter the groundwater and become part of Tucson’s water supply.

Figure 4-1 Observers watching the 1983 flooding of theSanta Cruz River in area just north of St. Mary’s bridge.

Photo: Peter KresanÓ

The occurrence and intensity of floodingin southern Arizona appears to have increasedduring the last 30 years. While periodic changesin weather affect floods to a degree, human fac-tors have played a greater role in determiningflood damage. Floods that occur in wildernessareas are hardly noticed because humans usu-ally are not affected. Floods that occur in ur-ban areas, however, can affect large numbers ofpeople and thus attract attention.

Urbanization is an important factor toconsider when assessing the intensity of floodsin Arizona. As Tucson has grown, much of thenatural land surface of the area has been gradedand covered with impervious surfaces — build-ings, roads, sidewalks, parking lots, etc. —increasing runoff. In a natural desert environ-

ment only about threepercent of the rainfallreaches the washes. Inan urbanized area,about 18 percent of therainfall flows to washes.The additional water inrivers and washes meansthat downstream flowsincrease in quantity andvelocity. Channels en-large, becoming deeperand wider, with erosionposing a greater threat.

As Tucson urban-ized, flooding becamemore menacing. Alongtheir urban reaches, theRillito Creek and SantaCruz River have be-come deeply incised,

with their channel bottoms as much as 40 feetbelow their banks. Waters no longer overflowthe banks as they did when the rivers were shal-low streams. Meanwhile homes and businesseshave been constructed along river banks in thebelief they are safe from floods. In reality, how-ever, many areas become subject to bank ero-sion that can threaten structures. Soils that aredry most of the year quickly break up when wa-ter flows swiftly against them. Erosion is mostlikely to occur on bends in the river where wa-ter flows swiftly towards the bend, striking itwith great force. In the 1983 flood, for exam-ple, bank erosion caused buildings to fall intothe Santa Cruz River south of Ajo Way andinto the Rillito Creek near First Avenue (SeeFigure 4-2).

Some natural resource managers stress thatfloods, although now influenced by human ac-tivities, are natural and often beneficial occur-rences, neither bad nor dangerous. Humans,however, have put themselves in harm’s way, bybuilding on floodplains and encroaching onflood-prone areas. Floods then threaten humanlife and property and are perceived to be an in-timidating menace to be confronted with ad-ministrative and technical ingenuity. Inresponse, public officials devise and implementflood control measures to protect life andproperty. Measures that are adopted to controlflooding, however, often have unintendedconsequences.

COPING WITHFLOOD HAZARDS

A comprehensive approach to floodmanagement may encompass physical struc-tures to protect bridges and other facilities, pro-grams and ordinances to regulate the use offloodplains and purchases of flood prone land.

Structural StrategiesA structural approach consists of physical

modifications to adjust and change the flow offloodwaters. For example, stormwater often wasconsidered best managed and controlled ifmade to flow expeditiously from an area. Struc-tural methods were adopted to widen,straighten and channelize waterways in effortsto reduce damage. Structural methods includedsuch measures as levees, channel stabilizationand storage reservoirs. These methods often


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Figure 4-2 The 1983 flood destroyed homes along the Rillito Creekat First Avenue. Photo: Peter Kresan.Ó

were applied to prevent bank erosion, Tucson’spriority flood damage problem.

Between the 1950s and the 1970s, vegeta-tion was often removed from channels thatwould then usually be straightened and coatedwith concrete. This was done to quickly directwater from an area. Examples of this approachcan be seen at Kino Boulevard south of Broad-way and at 12thth Avenue south of I-10. Thisoperation protects the immediate area, but is li-able to increase the rate of flow downstream,causing greater downstream damage. Channelssubject to this procedure are not suitable re-charge sites.

Starting in the 1970s, Pima Countyadopted a new technique and stabilized riverbanks with soil cement along the Santa Cruz

River and RillitoCreek. (See Figure4-5.) Soil cement ismade from a mix-ture of cement andriver soil and is ap-plied to the banksof a channel. Insome areas, largerocks are held inplace along bankswith wire meshing,to stabilize thebanks. Calledrip-rap, this con-struction needs reg-ular maintenance toprevent it from de-teriorating and be-ing washed away.Both of

these methods allow for recharge inthe channel bottom, but not alongthe previous floodplain.

Such structural methods forcontrolling floods may successfullyresolve a local concern but may re-sult in other flood-related problemsdownstream. For example, withbank stabilization in place, erosionmay be controlled and even elimi-nated along a stretch of a waterway.More runoff, however, then flowsdownstream with greater force, re-sulting in increased erosion ofbanks and, therefore, greater down-stream flood damage. Also, theforce of the water flow may move

the site of natural recharge to downstream areaswhere it may not benefit major wells.

Nonstructural MeasuresAs the result of above-mentioned concerns

— many of which are now the focus of politicaldebate — flood control strategies that rely onnonstructural methods have grown in impor-tance. Such methods avoid physical modifica-tions of the environment and instead maintainthe natural conditions of river channels.Nonstructural measures generally encourage so-ciety to adapt to natural flood conditions whenoccupying or modifying a floodplain.

Floodplain management is the full range ofcodes, ordinances and other regulationsadopted for minimizing flood damage, in-cluding zoning codes, building codes and sub-division regulations that may either prohibit

Chapter 4. Coping With Floodwater

37

Figure 4-3 Effects of bank protection on a riverbed.

Figure 4-4 Bank stabilization structure underconstruction west of Campbell Avenue.

Photo: Peter Kresan.Ó

construction in flood-prone areas or allowsome construction under certain conditions.Floodplain regulations also may be enacted toprevent consumer fraud by requiring disclosureof possible flood hazards. It can also includeflood forecasting, information and education,disaster preparedness and assistance, warningsystems, evacuation, flood insurance andfloodproofing.

Arizona law requires cities and counties tohave flood management programs. Both Tuc-son and Pima County, however, go furtherthan the state requires and have ordinances toencourage leaving floodplains as natural as pos-sible, including the use of native vegetation.The Federal Emergency Management Agency(FEMA) requires communities to adopt ap-proved floodplain maps and to regulate use of

the identified floodplains for residents toqualify for flood insurance. EPA requires man-agement of urban stormwater to minimize pol-lution, and both Tucson and Pima Countyhave approved stormwater management plans.A full discussion of these requirements is be-yond the scope of this report, although someadditional information is contained inChapter 7.

Floodplain Acquisition Since the 1980sPima County has actively acquired flood-pronelands to keep them from being developed in or-der to minimize downstream flood problemsand reduce flood rescue costs. These areas canthen be used for open space recreation andwildlife habitat. Cienega Creek, a perennialstream south of Saguaro National Park East, isa prime example of this approach. PimaCounty owns a portion, and most of the up-stream area is also public land under ownershipof the U.S. Bureau of Land Management andthe U.S. Forest Service. Tucson and PimaCounty also have acquired flood-prone landsand developed linear parks, often in coopera-tion. Much of the land along the Santa CruzRiver, both upstream and downstream of thedowntown area, is now in public ownershipand used as a linear park. The City of Tucson’sMultiple Benefit Water Projects propose waysof using CAP water to develop areas along theSanta Cruz River for wildlife habitat and recre-ational purposes.

Tucson’s Stormwater Master PlanA watershed is a geographic area defined by

the flow and movement of surface water, withall flow feeding one watercourse. The Colorado


38

Figure 4-5 Main floodway and bank reinforcement.

Sources:Tucson Water; Pima County Technical Services.

River watershed is made of many smaller water-sheds, including the Gila River watershed,which in turn is made up of many smallerones, including the Santa Cruz River water-shed. Encompassing the flow of runoff withinan area, a watershed is a hydrologically appro-priate unit to determine the management ofstormwater. Without such an approach, landuse policies upstream may not be coordinatedwith the principles for managing stormwaterrunoff downstream.

The City of Tucson’s Stormwater MasterPlan is an ongoing effort to develop a compre-hensive stormwater management plan with a re-gional, watershed focus. A comprehensiveprogram covering an entire watershed providesa much more favorable basis to plan presentand future runoff management needs. A “sys-

tem” or watershed approach also enables thecity to minimize its reliance on structuralstormwater control solutions and better pre-serve and enhance natural water courses.

To help accomplish its goal, the masterplan has identified 59 urban watersheds withinsix general hydrologic units or areas with simi-lar geographic and hydrologic characteristics,all located within Tucson. In this context, a wa-tershed is defined as a geographical area whichcontributes stormwater runoff to a particularpoint.

During Phase II of the stormwater study adatabase was established that included informa-tion on the physical characteristics of the drain-age systems in each of the city’s 59 watersheds.The study established a prioritization schemeto identify how individual watersheds ranked

with regards to the poten-tial for stormwater qual-ity problems. Watershedswere examined by lookingat human and naturalconsiderations affectingthem. Factors consideredinclude estimated con-taminant loadings, loca-tions and extent ofindustrial and commer-cial areas as well as the ex-istence of riparian areas.

Santa Cruz RiverWatershed BasinProject

An ongoing SantaCruz River Watershed Ba-

sin study is addressing flooding and other is-sues. The Santa Cruz River watershed covers ap-proximately 8,600 square miles in SouthernArizona. The watershed study is concentratingon the portion of the Santa Cruz River systemwithin Pima County.

The intent of the project is to address acluster of public concerns including environ-mental resources, floodplain management, reg-ulatory activities, erosion control, wastewatermanagement, groundwater management andflood control. The goal of the study is to de-velop a basin management plan for the SantaCruz River system. This plan is to guide futureprojects attempting to balance watershed con-cerns of environmental protection/restorationand economic development. Projected benefitsof the project include a flood control riverplan; land-use and regulatory tools for balanc-ing competing uses; a protection and manage-ment guide for existing and future riparianareas; a river maintenance guide to maintainingflood conveyance and storage capacity whileprotecting environmental resources; and waterquality identification and recharge opportuni-ties.

The U.S. Army Corps of Engineers is con-ducting the study, with the involvement ofstate, county, city and other federal agencies,San Xavier District of the Tohono O’odhamNation, International Boundary and WaterCommission and various public and private in-terest groups. The study is expected to cost $2million, to be shared between federal andnon-federal partners, and to be completedJanuary 2000.


39

Figure 4-6 Floods damage the Ina Road Bridge.Photo: Peter Kresan.Ó

CAPTURING RIVER FLOW

For many years people have looked forways to keep more river water in the area,rather than letting it flow downstream to PinalCounty. They noted the construction of damsalong the Salt River which retain water in reser-voirs to be released for later use. A major differ-ence between the Santa Cruz watershed and the

Salt River watershed, however, is that no practi-cal sites for large storage dams are locatedalong the Santa Cruz River or its tributaries.

In recent years, the U.S. Bureau of Recla-mation, the U.S. Army Corps of Engineers andPima County have looked at the feasibility ofusing inflatable dams to detain water tempo-rarily so that it will infiltrate the riverbed andseep underground. Inflated to capture runoff,

the dams can be deflated when major floodingcould pose a threat to the structure. So far noproject has been built.

Artificial Instream RechargeArtificial recharge is discussed in Chapter

3. In this section we look at the possible im-pacts of instream recharge projects on rivers.Many people view streambeds as ideal locationsfor artificial recharge since streambeds generallyprovide the best sites for natural recharge. Arti-ficial recharge in riverbeds may even be seen asrecreating historic conditions of river flow.While streambed recharge has many benefits,projects must be carefully designed so that theydo not lead to increased flood problems down-stream. If the river is already flowing at thetime of a large flood event, flood impacts mayincrease, depending on the quantity of the cu-mulative flow.

If the flood event occurs when the channelalluvium and basin fill are saturated with water,mounding of recharge water may cause lessstorm water to infiltrate in the area of the re-charge project and more recharge to occurdownstream instead. In some cases it will occurout of the range of the major wells. Streambedrecharge projects also may increase vegetationin the channels as a result of more availablesoil moisture. This vegetation could increasethe risk of flood damage because it reduces theamount of water that the stream channel cancarry. This vegetation, however, also can havemany advantages from an aesthetic point ofview, as wildlife habitat and for recreationaluse.


40

Figure 4-7 A view towards the Santa Rita Mountains around 1900, showing the Santa CruzRiver and part of its watershed. Source: Tucson Souvenir Portfolio about 1904.

The issues are obviously complex, and pro-posed artificial recharge projects should be care-fully studied both for their recharge potentialand for their impacts on flooding. Eachinstream recharge project must be evaluated in-dividually, since conditions vary so much fromsite to site that no generalizations about the im-pacts of recharge on flooding will apply to allsituations.

WATER QUALITY

The variety of solutions to flooding prob-lems has improved flood and erosion protec-tion in many areas, but also has affectedrecharge in rivers. Before urbanization, floodwaters spread out over a broad area and movedslowly downstream. This enhanced natural re-charge, with more flood waters reaching the

aquifer. With waters now often confined withinrigid, usually impervious channel walls, muchof the water moves swiftly downstream withoutrecharging.

Also, more of the desert area now iscovered with roads, parking areas, and build-ings constructed on land where water oncesoaked into the soil. Impervious surfaces gener-ally cover approximately 20 percent of a subur-ban watershed area which usually has twohouses or less per acre. In a highly urban water-shed impervious surfaces cover approximately70 percent or more of the surface area. Highlyurban watersheds contain six or more housesper acre, and include commercial, industrialand multiple dwelling uses, with extensivedrainage improvements.

Flowing rapidly and temporarily floodingstreets, this water can pick up a wide variety of

pollutants, carrying them to rivers. Because ofinfrequent rains, oil tends to build up on Tuc-son streets. During the first big storms of sum-mer, Tucson streets tend to be slippery fromthis oil that flows with the flood waters. Moreauto accidents occur at this time than later inthe rainy season when the streets have been par-tially cleansed by flowing water. More informa-tion is needed to determine whether pollutantsin stormwater runoff have a significant impacton groundwater quality.

Because of the various urban conditions,less recharge occurs during big storms thanwould occur if conditions were more natural.Not only is water that could possibly be re-charged leaving the area, but some of thestormwater that does recharge may be pollutedfrom urban conditions. Old landfills locatedalong river channels can be the source of fur-ther pollution entering the groundwater duringflooding.


41

WATER USES

Water is used for many purposes, includ-ing growing crops, producing copper,generating electricity, watering lawns,

keeping clean, drinking and recreation. Bal-

ancing the water budget comes down to increas-ing the supply and/or decreasing the demand.In Chapter 3 we discussed the supply side ofthe water budget. Reducing demand involves re-ducing how much water each person uses, lim-iting the number of people using water (or

slowing the rate ofgrowth), and/or replacingsome uses with other uses.To understand what thesechoices are, we must firstunderstand how water hasbeen used in the past andhow it is used today.

There are three majorgroups of water users:homes and businesses, ag-ricultural interests, andindustry (including min-ing). The increase in mu-nicipal water use duringthe 1980s was offset bydecreasing agriculturaluse, with total water usein the Tucson area hold-ing steady during this pe-riod at about 275,000

acre-feet. (See Figure 5-1.) Agricultural use hasrisen since 1993. That, coupled with rising mu-nicipal use, pushed total water use to 323,000acre-feet by 1997.

Agriculture has historically consumed thelargest share of water of any sector in the Tuc-son area. After reaching a plateau between 1955and 1975, however, agricultural water use de-clined during the 1980s and early 1990s. Mu-nicipal water use has increased since 1984 asthe population has grown — both in totalacre-feet used and in percentage of total wateruse, and now consumes a larger share than doesagriculture.

MUNICIPAL WATER USE

Population growth has caused municipalwater use to be the fastest growing water usesector. Total municipal water use in the TucsonActive Management Area (TAMA) increasedfrom approximately 116,000 acre-feet in 1985to about 154,000 acre-feet in 1997.

One hundred and fifty-one municipal wa-ter providers operate in the Tucson area. Ofthis number, 19 large providers serve over 96percent of total municipal demand. The service

43

Chapter 5

THE MANY USES

OF WATER

In a complex society water use is varied, from municipal and agricultural

to mining and other industrial uses. This chapter discusses these broad

categories of water use, describing activities that are included within each

category. For example, municipal water use includes diverse activities, from

plant watering to toilet flushing. Data are provided to show how much

water is consumed by various types of water users. The cost of water also is

discussed since cost is an important consideration when analyzing water use.

Each section ends with possible ways to reduce water use.

Figure 5-1 Annual water use by sector, Tucson AMA.

Source: Arizona Department of Water Resources, 1984 - 1997 Annual Withdrawal and Use

Summary, Tucson AMA.

areas of the major water providers are shown inFigure 5-2. See Appendix B for a complete listof municipal water providers and number ofcustomers served.

Tucson Water is by far the largest munici-pal provider in TAMA, serving approximately75 percent of total municipal demand. Approx-imately 40 percent of the population served byTucson Water resides outside of the city limits,mostly in unincorporated areas of Pima

County. Tucson Water’s service area is pro-jected to continue to grow, but the rate ofgrowth has been slow. Metropolitan DomesticWater Improvement District (Metro Water)serves the next largest population. Other waterproviders closer to the edges of the Tucson met-ropolitan area, such as Oro Valley, Avra Water,and Metro Water, tend to be the fastest grow-ing. Rapidly growing service areas generally areareas of rapid population growth and newer

homes. These homes are likely to have wa-ter-saving fixtures and smaller yards, but arealso more likely to have certain water consump-tive facilities such as swimming pools.

TYPES OF MUNICIPALWATER USE

Tucson Water's total water usage rate in1955 was 172 gallons per capita per day (gpcd)including both residential and non-residentialcustomers. It has remained fairly constant since1985, ranging between 176 and 169 gpcd. Somechanges in use relate to different weather condi-tions. For example, people tend to use morewater during hot, dry summers than during rel-atively cooler, wetter ones. More homes havingswimming pools and other water-using featuresincreases water usage while installing low-wateruse toilets can decrease consumption.

Residential customers (single family andmulti-family) are considered municipal waterusers along with businesses and institutions.Water use characteristics generally differ foreach category of demand, with residents con-suming most of the water in the municipal cat-egory. Residential demand for Tucson Waterhas remained fairly consistent at about 110gpcd from 1985 to 1995. The average residen-tial consumption rate for other large providersis higher, averaging about 121 gpcd. A numberof factors explain the higher consumption ratesof these large providers, including the age ofthe housing within the service area, the avail-ability and effectiveness of conservation pro-grams, income levels and water rates.


44

Figure 5-2 Municipal water provider service areas.

Sources: Pima County Technical Services, Arizona Department of Water Resources, Water CASA.

Residential UseSingle family residents account for approxi-

mately 75 percent of residential demand in theTucson area. Multifamily residential demandmakes up the balance. These include apartmentcomplexes, duplexes, triplexes, townhouses andcondominiums. Their use is typically about 60percent of the single family residential use rate.Multifamily complexes use less water per per-son in part because landscaping is generallylimited to common areas, and some water usesoccur away from the residence; e.g., apartmentdwellers are more likely to use and car washes.

During the 1970s and 1980s new housingconstruction shifted towards multifamily dwell-ings. This increased construction of lower wa-ter-use housing promised to reduce gpcd rates.This trend, however, did not continue. Eco-nomic expansion and much lower mortgagerates caused single family home construction to

rebound. In addition, the majority ofmultifamily units being constructed are moreluxurious units which are more likely to havelarge turf areas, pools and other water-usingamenities.

Older homes tend to consume more waterboth indoors and outdoors than newer homes.They generally use more water outdoors be-cause of larger lots with more turf and land-scaping. They use more indoors because theyare less likely to have low-water use fixturessuch as ultra low flush (ULF) toilets designedto use 1.6 gallons per flush. Homes built after1975 are less likely to have lawns, and homesbuilt after 1989 are required to have ULFtoilets.

Nonresidential UseNon-residential demand generally consists

of turf facilities (golf courses, cemeteries, etc.),water features in public rights-of-way and com-

mercial establishments. Non-residential de-mand for large providers averaged 41 gpcd in1995. Tucson Water’s non-residential demanddecreased by six gpcd from 1985 to 1995. Forother large providers, however, non-residentialdemand increased by 11 gpcd. Tucson Waterhas been able to reduce its gpcd rate by switch-ing some golf courses and other facilities to ef-fluent. (Although considered water, effluentdoes not count in the official calculations.)Other large providers are serving an increasingnumber of golf courses but do not have accessto reclaimed water. As a result, their water useappears greater. Some areas served by large mu-nicipal providers are experiencing a transitionfrom bedroom communities to areas with moreretail and commercial activity, a change that isreflected in their water use.

The 35 golf courses in the area account forabout ten percent of municipal water use inTAMA. The total amount of water used onTAMA golf courses has increased from 11,700acre-feet in 1985 to 17,000 acre-feet in 1997.(See Figure 5-3.) Of the total amount of waterused on golf courses in TAMA, the share of ef-fluent increased from 24 percent in 1985, peak-ing at 38 percent in 1990, and has since fallento 35 percent in 1997.

The number of holes of golf in TAMA hasincreased by 35 percent since 1985. Golf coursedesign in the area has shifted towards moredesert-like courses, incorporating fewer waterhazards and significantly more low-water useplants along fairways instead of turf. In addi-tion, the average number of acres of turf perhole has decreased from 5.9 in 1985 to 4.8 in1997. However, reductions in water use result-ing from these changes have been offset by a

Chapter 5. The Many Uses of Water

45

Table 5-1 Selected water providers in the Tucson metropolitan area(1995 data).

WATER PROVIDERPOPULATIONSERVED

GROUNDWATERDELIVERIES (af)

RESIDENTIALGPCD

Tucson Water 559,602 109,927 110

Metro Water 42,861 8,557 148

Oro Valley 23,229 5,707 116

Flowing Wells Irrig. Dist. 14,951 2,842 127

Community Water Companyof Green Valley

12,819 2,063 112

Avra Water Co-op 5,663 771 105

Ray Water 4,617 599 106

large increase in the percentage of golf courseturf which is overseeded with winter rye grass,from 21 percent in 1985 to 66 percent in 1997.The water use per hole of golf has increasedover time since 1985, in part due to variationsin weather.

Other large-scale turf facilities includeparks, cemeteries and schools. For legal reasonsArizona Department of Water Resources(ADWR) divides turf facilities into industrialand municipal categories according to whetheror not they are served by municipal water pro-viders. All these turf facilities use about 20,000acre-feet of water, about 33 percent of which iseffluent. The remainder is groundwater.

Patterns of water use for retail and com-mercial establishments vary widely, but ofteninclude water for sanitary and landscaping

needs. The number of employees often is a sig-nificant factor in business water use. Partly be-cause water use patterns vary significantlyamong businesses, water audits tailoring conser-vation measures to particular needs are an ef-fective strategy for reducing business water use.

CONSERVATION RULES

Under the Groundwater Management Act,ADWR sets goals for per capita water use bymunicipal water providers, but cannot regulateindividual customers. Large providers canchoose among four water conservationprograms. Most often selected is the TotalGPCD program, which sets targets for reduc-tions in per capita water use for each water pro-vider based on an analysis of conservation

potential for that provider.Tucson Water and MetroWater have selected thenon-per capita conservationprogram; they do not haveto meet specific per capitawater use targets, but mustimplement a range of con-servation measures. Smallproviders, which account forfour percent of total munici-pal water use, are regulateddifferently than large provid-ers. Small providers are re-quired to reduce waste andencourage conservation, butthey generally lack the re-sources to implement con-servation programs.

Other ways ADWR tries to balance supplyand demand include requiring developers todemonstrate that renewable supplies are avail-able to serve the development; that water use isconsistent with TAMA’s management plan andgoal; and that the developer has the financialcapability to construct needed water facilities.These Assured Water Supply (AWS) rules aredesigned to work with the conservation pro-grams to reduce mining of groundwater.

USE OF RENEWABLE SUPPLIES

Historically, Tucson has been largely de-pendent on groundwater, a mostlynon-renewable supply. In the past twenty years,however, effluent use has increased and CAPwater has arrived in the area.

Central Arizona ProjectCAP is potentially our largest renewable

water source, although the only current directuse of CAP water in the municipal sector oc-curs for treatment plant maintenance — about200 acre-feet in 1997. CAP’s potential as a watersource obviously is not fully realized.

EffluentEffluent use currently meets about five per-

cent of municipal water demand. Of the 69,400acre-feet of effluent produced at the Ina Roadand Roger Road wastewater treatment plants in1998, about 13,000 acre-feet was reused, withthe rest discharged to the Santa Cruz Riverchannel, where some 96 percent eventually re-charges the aquifer within TAMA. Of theamount reused, approximately 1,200 acre-feet


46

Figure 5-3 Water use on Tucson AMA golf courses.

Source: Arizona Department of Water Resources, Tucson AMA.

was delivered directly to turf facilities and some3,000 acre-feet was delivered to the CortaroMarana Irrigation District. This effluent onlyhas secondary treatment and is mostly delivereddownstream via gravity.

The City of Tucson processed approxi-mately 8,700 acre-feet of secondary treated ef-fluent at its reclaimed water facilities locatednext to the Roger Road Wastewater TreatmentFacility. This effluent receives further treatment(tertiary treatment) by filtration through sandfilters or soil and additional disinfection. Thereclaimed water then is delivered for use or isstored at the Sweetwater Underground Storageand Recovery Facility (recharge facility) to meetpeak demands in the summer, primarily to irri-gate golf courses.

Reclaimed water flows through a differentset of pipes, separate from the potable water

system. So far, $66 million has been spentbuilding the system, including the reclamationfacilities, the recharge facility and the distribu-tion system. Tucson charges $475 per acre-footfor reclaimed water. Full cost for productionand distribution of reclaimed water is about$558 per-acre foot, with $323 covering debt ser-vice and capital costs and $235 covering opera-tion, maintenance and overhead costs. Theprice charged for reclaimed water is substan-tially lower than the wholesale price TucsonWater charges for potable water. This is done tofurther encourage the use of effluent.

Figure 5-5 shows Tucson’s 85-mile re-claimed water system, which has about 200 us-ers. New users pay the cost of connecting to thesystem. This cost can be quite high, due to theexpense of extending pipe to carry the effluentto the new user and modifying the user’s deliv-

ery system to handle effluent.A City of Tucson ordi-

nance requires the use of efflu-ent on new golf courses wherepossible. Since 1983, all newgolf courses served by TucsonWater have been connected tothe reclaimed water system.Currently, 12 of 16 courses inthe Tucson Water service areaare using reclaimed water, andone is using groundwater untileffluent can be delivered. Thethree other courses use waterfrom their own private wells.There is no current authorityto prohibit their use of ground-water. Pima County’s 1995 zon-ing code amendments require

that all new golf courses use effluent or CAPwater for turf-related watering where available.The expense of constructing pipelines usually isthe limiting factor. A new ordinance passed inMarch 1999 requires the use of CAP or effluentat all new golf courses within three miles of atreatment plant or CAP water line. Owners ofgolf courses outside those areas now have tofind a way to recharge CAP water to replace thegroundwater they use on golf courses. Attor-neys are looking at whether this ordinance alsoapplies to 13 existing golf courses in thecounty.

ADWR incentives encourage the use of ef-fluent. The most important incentive allowsmunicipal providers to exclude effluent usedon golf courses from their gpcd calculations(although the same total amount of water is ac-tually used) which means conservation goalsfor individual customers can be higher.

Graywater ReuseGraywater is water recovered after various

indoor household uses, excluding toilet use.Graywater includes water from clothes washers,bathroom sinks, showers, baths, dishwashersand sometimes the rinse side of the kitchensink. A graywater reuse system can be set up tocapture and recycle such water for uses not re-quiring drinking water quality water; e.g., land-scape irrigation. Approximately 60 to 65percent of the wastewater generated from resi-dential indoor use is graywater. The average res-ident generates an estimated 30 gallons ofgraywater per day. This is a significant sourceof water available to meet peak outdoor irriga-tion demands in the summer.


47

Figure 5-4 Treated effluent at a golf course.Photo: Barbara Tellman.

Although graywater use is common in ru-ral areas and has been practiced by many peo-ple in urban areas for years, graywater reuse istechnically illegal in many places in the UnitedStates. Plumbing codes generally require watercoming from the drain to be discharged to thesewage system or a septic tank. In Arizona, apermit must be obtained from the Arizona De-partment of Environmental Quality (ADEQ)or the Pima County Department of Environ-mental Quality to operate a graywater reuse sys-tem. To issue a permit, ADEQ must approvethe design and construction of the system. Thesystem must include a settling tank to settle outgrit in the water and also must have a filtrationdevice. Water to be applied to the surface of theground (defined as within two feet of theearth’s surface) must be disinfected, meet waterquality standards and be monitored. Daily test-ing of the samples may be required and can beexpensive.

Such hurdles to legal use of graywater causemany residents to forego graywater reuse, whileothers become “wildcat” graywater users, apply-ing it without official approval. A survey ofTucson Water customers in the early 1990s re-vealed six percent of customers had graywaterreuse systems. A more recent survey of MetroWater customers showed that nine percent ofhouseholds use graywater. Since graywater useis illegal, respondents may be reluctant to ad-mit to its use, and the actual percentage ofthose reusing graywater may be higher than sur-veys show.

Concerns about public health are the big-gest obstacles in legalizing graywater use. Thequality varies depending on how it was used.Water from washing diapers, for example, will

probably be more contaminated than waterfrom a shower. Fecal coliform bacteria levelsand nitrates have been of particular concern, al-though the threat is perhaps exaggerated. Sal-monella and polio virus have been shown tolast several days in graywater. Data accuratelycharacterizing factors that determine graywaterquality and assessing risks of use is limited.Studies are needed to develop guidelines for thesafe reuse of residential graywater. The Water

Conservation Alliance of Southern Arizona(Water CASA), in cooperation with ADWR,ADEQ and Pima County Department of Envi-ronmental Quality, is studying residentialgraywater reuse in Tucson. Study results willhelp determine if health risks increase withgraywater reuse, and whether permitting stan-dards can be loosened.

Graywater reuse has limited potential forhelping TAMA reach safe yield. For the 85 to


48

Figure 5-5 Golf courses and the reclaimed water system.

Sources: Pima County Technical Services, Tucson Water, Arizona Department of Water Resources.

90 percent of homes connected to the centralsewage system, water used as graywater does notenter the sewage system to be treated for reuseor discharged to the Santa Cruz River. About96 percent of the treated water that is releasedinto the Santa Cruz River recharges the aquiferin TAMA. The use of water at a domestic siterather than treated and used someplace else getsus no closer to TAMA-wide safe yield.

However, residential graywater reuse can bean effective tool to better manage our ground-water by matching water quality to the actualquality needed for a particular water use. Resi-dential graywater reuse reduces the demand forgroundwater. Less water will then be withdrawnfrom areas of serious water table declines, suchas Tucson’s Central Wellfield. Graywater reusealso saves the cost of moving groundwaterthrough the water system, from disinfection todelivery to eventual sewage treatment. Further,a sizeable reduction in the waste stream goingto the treatment plant could reduce its operat-ing and capital expenses and delay the need forexpanding those facilities.

RESIDENTIAL WATER USE

Pima County’s population is projected toincrease from today’s figure of about 836,000to 1.3 million by the year 2025. Most of thatgrowth is expected to occur in the Tucson met-ropolitan area. As the population grows, totalwater use will increase.

If per capita water use rates stay about thesame as today, total municipal water demandwould increase from 172,900 acre-feet in 2000to 267,100 acre-feet in 2025. The water savingpotential of both new and existing housing

must be examinedfor appropriateways for a diversepopulation livingin varied housingto conserve water.

Water can beconserved bothindoors and out-doors. Most ofthe water used in-doors winds up ina sanitary sewer orseptic system. Forhomes hooked upto the sewer sys-tem, water usedindoors is re-usedor recharges the aquifer. Much of the waterused outdoors evaporates and leaves TAMA.Therefore, saving water outdoors has a greatereffect on the total water budget for the Tucsonarea than does saving water indoors. Saving wa-ter indoors, however, does reduce the cost oftransporting water to the treatment plant andtreating it.

It is important to note, however, that givenTucson’s projected population growth, no levelof water conservation, even if involving alltypes of water users, will be sufficient to ensurea balanced water budget.

Indoor Water UseIndoor uses remain fairly constant

throughout the year. People may wash moreclothes in the summer, but in the winter thebulk of clothes washed is greater. Similarly,

other indoor water uses vary little during thecourse of the year. This constancy is reflectedin relatively flat levels of sewage water flow.

Figure 5-6 shows that the largest indooruses of water are toilets, showers and baths, andwashing machines in all types of housing.Newer models of toilets are designed to use lesswater than older models. Until the early 1980s,most new toilets used five to seven gallons perflush. Water-conserving 3.5 gallons per flushtoilets were the standard until the early 1990swhen 1.6-gallon ultra low flush () toilets be-came available. In 1989, both Tucson andCounty adopted ordinances requiring installa-tion of ULF toilets in new construction.

Replacing older toilets with ULF toilets isone of the best ways to save water indoors. ULFtoilet savings do not require a change in behav-ior and, if the toilet continues to functionproperly, will effectively save water. However,


49

Figure 5-6 Typical single family home indoor water use.

Source: Data are a copyright of the American Water Works Association and were compiled for

WaterWiser, www.waterwiser.org, by John Olaf Water Resources Management.

while many models of ULF toilets functionvery well, recent anecdotal evidence indicatesthat some models of ULF toilets deteriorateover time. Further, replacement parts are notreadily available for some models, forcinghomeowners to find alternative parts that cannegate the water saving feature of the toilet.Other people continue to use ULF toilets with-out making repairs; this also results in less wa-ter savings. The University of Arizona’s WaterResources Research Center is conducting astudy to identify the extent of this problem andto determine which models of ULF toilet havenot held up over time. This information can beused to rewrite plumbing codes, upgrade ULFtoilet quality, and make the correct replacementparts easier to obtain.

Toilet dams and other water displacementdevices can help save water in older model toi-lets. Toilet dams, which are placed in the tankto keep water from fully filling the tank, typi-cally save about one gallon per flush. Wa-ter-filled bags or plastic bottles also can be usedin place of dams and typically save about thesame amount.

Showers and baths are another large com-ponent of indoor water use. Showers and bathstypically comprise about 20 to 25 percent of to-tal indoor water use in older homes. Low-flowshower heads also can save water. Older showerheads typically use 3.5 gallons per minute(gpm), while low-flow shower heads typicallyuse 2.5 gpm or less.

Clothes washers typically account for be-tween 20 and 25 percent of indoor water use.Clothes washers vary widely in their water use.Older models used about 55 gallons per load,while more water-efficient models use around

42 gallons per load.Newer, more efficientmodels, including hori-zontal axis machines, useabout 30 gallons per load.

Faucet use typicallyaccounts for around 15 to20 percent of indoor use.Faucet aerators reducesome water use by intro-ducing more air into thestream, thereby increasingthe water’s wetting action.This can save approxi-mately one gpm overolder 3.5 gpm faucets.Other faucet uses, such asfilling a glass or teapot,are unaffected by aerators.

Leaks average approxi-mately 10 percent of indoor water use. Inspec-tion of the home for leaks as part of a wateraudit is often an effective way to save water.Tucson Water offers free leak detection as partof its Zanjero Program, which provides custom-ers an analysis of the water use in their home,and information on how to lower their wateruse and water bills.

Outdoor Water UseIn the Tucson area, single family residents

use 30 to 50 percent of their water outdoors,for landscape watering, swimming pools, spas,evaporative cooling and other such uses. Out-door water use varies over the year. In the sum-mer before the monsoon rains starts, outdoorwater use peaks as plants require more water to

survive and evaporation from pools is at itsgreatest. In the winter, outdoor water use dropsdramatically, especially during the winter rainyseason from January through March. Bermudagrass is dormant during this season, and onlyabout seven percent of landscapes have winterrye grass lawns.

Peak summer water use can be up to twicewinter water use. Beat the Peak, the water con-servation campaign created by Tucson Water af-ter the 1975-76 water controversy, was designedto help cut peak consumption. Water providersmust design their distribution systems to meetpeak demand and allow enough reserve supplyfor fire fighting. If peak demand is reduced,costs are reduced. A benefit is that lower peakdemand has generally also meant lower totalwater use.


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Figure 5-7 Water is saved when a landscape consists of desert,drought-tolerant vegetation. Photo: Barbara Tellman.

Landscape irrigation is the largest categoryof outdoor water demand. Most landscaping inTucson combines grass with desert plants. A1992 random survey of Tucson Water custom-ers found that about 43 percent of respondentshad some grass in their landscaping. Eight per-cent of residents reported their landscaping wasmostly grass while the other 35 percent hadlandscapes combining turf area with otherplant materials.

Since the late 1940s, the percent of newhomes with lawns has generally been decliningin Tucson. A 1983 random survey revealed thatabout half of the homes built prior to WorldWar II had lawns. The percentage of homeswith lawns declined gradually though themid-1970s, and then declined steeply about thetime of the 1975-76 water crisis in Tucson.Most evidence indicates that roughly 20 per-cent of homes built in the late 1980s and early1990s have lawns.

Lawns are rarely removed once they are in-stalled. Converting lawns to desert landscap-ing, however, became more common in the late1970s and early 1980s. A sample of Tucsonhouseholds in 1979 showed that up to 20 per-cent of households surveyed had removed theirfront lawns, while 15 percent had removedtheir backyard lawns between 1976 and 1979.This compares to essentially no lawn removalin the several years before the crisis. Averagelawn size also has declined from a peak ofabout 2,000 square feet for homes built around1960 to around 600-800 square feet for homesbuilt since the mid-1980s.

Relying on a garden hose to water vegeta-tion is the most prevalent form of irrigation inTucson. Drip irrigation is the second most

common method of irrigation andhas gained significantly in popularitysince the early 1980s. At that time,one percent of households had drip,compared to approximately 27 per-cent of households in the early1990s. Approximately 22 percent ofTucson Water service area house-holds reported having in-ground irri-gation systems in the early 1990s.About eight percent of homes sur-veyed in the early 1990s did not irri-gate their landscaping at all.

Which irrigation system is mostefficient is unclear. Management ofthe system is as important as the sys-tem hardware. Drip systems andin-ground turf irrigation systems canbe put on timers and programmed todeliver the right amount of waterwhen needed. But timers need to bereset to adjust to changing seasonsand large rain events. Too often suchadjustments are not made. In suchinstances, hand watering with a hosecould be more efficient. Deep, infre-quent irrigation of mature landscapeplants is more efficient than fre-quent, shallow irrigation.

Swimming pools are less com-mon than lawns in Tucson, but thepercentage of homes with swimmingpools has been increasing over time.A swimming pool typically uses three to fivetimes as much water as the same area of turf.This is due in part to the fact that most privatelawns are under-irrigated, and pool consump-tion includes not only evaporation but also fil-

ter back flushing and occasional draining formaintenance.

As is shown in Figure 5-8, the percentage ofTucson homes with pools is a function ofwhen the home was built, increasing from


51

XERISCAPING

Xeriscaping is using efficient landscape designand lower water use vegetation to create attractivelandscapes — and equally important, to save water.The word “xeriscape” combines the Greek word“xeros”, meaning dry, with “scape” from “land-scape.” Xeriscaping principles make use of “micro-climates” that exist in the landscape. Micro-climatesare defined according to the amount of sun andshade, the slope, and air movement that character-ize a landscape.

The property is divided into low, medium andhigh water use areas, with the highest water use ar-eas close to the house, in areas with the most shade.These are cooler areas, and xeriscaping would limitturf to these areas. Drought-tolerant plants and na-tive vegetation are used in low water use zones toprovide attractive landscape with a variety of color-ful and interesting plants.

Water harvesting techniques might be applied tocapture and store rainwater for use on plants or tochannel runoff directly to vegetation. Drip irriga-tion can be installed to water individual plants,while sprinkler systems are used for turf. Soil can beimproved and topped with mulch to hold waterfrom rainfall as well as irrigation. Taken togetherthese practices help residents save both water andmoney while creating beautiful and interestinglandscapes.

about 15 percent in homes built prior to themid-1950s, to about 22 percent from themid-1950s though the 1960s, and then tonearly 30 percent in newer homes. At present,almost 20 percent of all homes in Pima Countyhave pools.

Many pools are not built at the same timeas the home, but rather within the first seven to

eight years after the homeis constructed. And onceconstructed, pools arerarely removed. Pool re-moval can cost over$10,000 and usually reducesthe value of the home. Thissuggests that the best timeto provide outdoor waterconservation messages tohomeowners is soon afterthey’ve moved into a newlyconstructed home and be-fore they have made land-scaping and pool decisions.

One of the few ways toreduce pool water use iscovering the pool when it isnot in use to minimizeevaporation. A survey ofnewer homes in Tucson re-vealed that approximately60 percent of home poolshave pool covers. But pool covers are used onlyabout half the year. Usage is at a minimumduring the summer swimming season to allowconvenient and frequent access to the pool.Also covers are not used in the summer becausethey cause the water to become uncomfortablywarm. Peak cover usage surprisingly is not inwinter, but in the fall and spring, when poolusers are trying to extend the swim season.Lower pool cover usage in the winter may re-flect a desire to protect the cover from sundamage while evaporation rates are the lowest.

Water for evaporative cooling systems ac-counts for around five percent of outdoor wa-ter use in Tucson. (Evaporative cooling is

classified as an outdoor water use because it re-sults in water being consumptively used andnot returned to the sewage system as is the casewith other indoor uses.) In 1992, approximately79 percent of homes in Tucson had evaporativecoolers. At that time approximately 59 percentof households had only an evaporative cooler;21 percent had both a cooler and an air condi-tioner; and 19 percent had only an air condi-tioner. As air conditioners have gainedpopularity in new construction, the percentageof Tucson homes with evaporative coolers,along with the amount of outdoor water de-voted to evaporative cooling, has declined. Ap-proximately 85 percent of new constructionsurveyed in 1996 had only an air conditioner,


52

WHAT MAKES UP TUCSON’SWATER DISTRIBUTION SYSTEM?

Sources of Water - Water pumpedfrom an aquifer to pipes for distributionand delivery has been the source ofmuch of Tucson’s water. Tucson’s newestavailable source of water is the CAP,which brings water from the ColoradoRiver. Tucson also has a system for us-ing treated wastewater on facilities suchas golf courses and parks.

Pipelines - Large pipelines (“watermains”) bring water from its source tocentral points, and smaller pipes distrib-ute that water throughout the commu-nity.

Reservoirs - These are storage areasthat hold water until used. Reservoirs areimportant for balancing supply and de-mand and for ensuring that an extraamount of water is in reserve for firefighting. At one time, elevated storagetanks provided adequate supplies of wa-ter. With our large population, however,huge reservoirs are needed, with capaci-ties ranging from one million to twentymillion gallons of water.

Figure 5-8 Fraction of residential lots with pool by yearhome built, Pima County 1920-1990.

Sources: Pima County, Water Resources Research Center.

11 percent had both an air conditioner and anevaporative cooler, and four percent had onlyan evaporative cooler.

HIGHER WATERUSE TRENDS

While newer homes have more low-flowplumbing fixtures and appliances and are likelyto have less turf and no evaporative cooler,some trends in new construction cancel outthese conservation gains. For example, newerhomes are more likely to have water using ame-nities such as pools, spas and whirlpool tubs.Further, new apartment complexes and condo-miniums are more likely to have large amountsof turf and landscaping, as well as pools.

The number of homes with outdoor mist-ing systems grew through the early andmid-1990s. These systems spray droplets of wa-ter into the air that evaporate to cool an area.Although manufacturers of misting devicesclaim water efficiency, few residential mistingsystems are as effective or water-efficient as ad-vertised, and some are poorly designed. Systememitters can scale up or corrode, producingdrips instead of the intended mists. A survey ofTucson Water customers in 1992 showed thatthree percent had misting systems. A MetroWater survey conducted about 1995 indicatedthat seven percent of homes had misting sys-tems, and a 1997 survey of new housing indi-cated that 12 percent of sampled homes hadthem. The 1997 survey showed that those sys-tems were used an average of 3.4 times perweek, and that the main use was for coolingpets left outdoors.

The trend in cooling system design is to-ward greater water use. The latest models ofevaporative coolers are designed to prolong thelife of the cooler by draining water after a cer-tain number of hours of operation. This pre-vents mineral content from building up andcorroding metal cooler parts and scaling upthe pads. Some new coolers, however, emptythe pan automatically after only a few hours ofoperation. This is excessive considering Tuc-son-area water quality. In older coolers, watercollects in the bottom of the cooler and can bedrained using a bleed-off valve. Some new airconditioners also use water. Manufacturers canachieve higher efficiency ratings by dissipatingheat generated by the unit in an attached evap-orative cooler.

Some water-using indoor appliances alsoare starting to use more water in settings de-signed to handle heavy loads. For example,Consumer Reports found that while new dish-washers have a greater number of settings tobetter match water use with job size, thepower-scrubbing option available on manymodels means significantly higher water use.New dishwashers use between four and 13 gal-lons per load on normal settings, but can usesignificantly more when set for the dirtiestloads. In contrast, washing dishes by hand usesthree to five gallons per load.

WATER RATES ANDCONSERVATION

For decades water has been priced as if itwere free. What people pay for is the cost ofcapturing the water, delivering it to them and

making sure it is safe to drink. People whopump their own water pay to build and operatetheir wells, but they do not pay anyone for thewater itself. ADWR, however, does charge wellowners a small pumping fee which goes primar-ily toward conservation and augmentation (wa-ter banking) programs. In some states peoplepay an annual fee for their pumping permitwhich recognizes that the state owns the waterand sets certain conditions for people to use it.

Many people will conserve water if theprice is very high. The point at which peoplewill respond to higher bills varies greatly, de-pending mostly on personal income and thepercentage of total household expense the waterbill represents. Some people may find a $100water bill acceptable while others may haveproblems paying a fourth as much.

Water rates can be modified to encourageconservation in two very different ways:

• The rate structure can be designed to re-ward conservation and discourage excessivewater use. For example, cost per gallon couldincrease as customers use more water; costcould increase at peak times of the day or yearto reflect higher costs at that time; or costcould be higher for areas that are more expen-sive to serve.

• Rate levels can be raised to cover the costof finding new future water supplies.

Changing Rate StructuresTucson’s first water rates in 1900 were flat

rates, as are some of Salt River Project’s ratestoday. A flat rate means people pay the samefor water no matter how much they use. Formany years, Winterhaven had a flat rate for wa-


53

ter, with the expectation that people wouldmaintain lush lawns and landscapes, althoughthis has changed and desert landscapes are nowacceptable in that Tucson neighborhood. To-day almost all communities nationally meterwater usage and thus charge people more forincreased water use.

Water bills from all water providers in theTucson area have two basic parts — a basic ratedetermined by the size of the connection (thisis a fixed charge applied whether or not wateris used) and a commodity rate which is chargedfor every unit of water used over a minimumamount. For many water providers, the mini-mum amount is 2,000 gallons. Some watercompanies charge a higher commodity rate forwater use above certain amounts (referred to asan increasing block rate or progressive ratestructure). This type of rate structure is de-signed to discourage high-volume water use.Tucson Water, Metro Water and Avra WaterCo-op have increasing block rates.

Another water rate structure variation de-signed to encourage water conservation is sea-sonal water rates. Seasonal rates usually involvecharging a higher commodity rate during sum-mer months than during winter months.Higher summer rates are designed to encouragemore conservation when more water is neededto meet peak demand on the water system.Metro Water has had seasonal rates since 1995.Tucson Water had seasonal rates for all cus-tomer classes from 1977 to 1995 but removedseasonal rates for the single family residentialand duplex-triplex classes in 1995.

Water rates are an important signal aboutthe relative scarcity of water and the need toconserve. If rates do not keep up with inflation,

the real price of water ac-tually declines. Peoplemay take that as a signalthat water is cheap andconservation is not im-portant. Even if the realprice of water is heldconstant, incomes inPima County have in-creased at a faster ratethan inflation. This isgood news for the econ-omy, but means that wa-ter bills shrink as arelative share of the over-all budget. The incentiveto conserve is reduced.

Tucson Water haspursued a water rate pol-icy designed to lower peak demand and encour-age water conservation. Tucson Waterinstituted increasing block rates and seasonalrates as a conscious effort to discourage exces-sive water use. Especially after the 1975-76 watercontroversy (S Chapter 2), many Tucson Watercustomers saw significant increases in their wa-ter bills, and water use decreased significantlyas the message to conserve hit home. At thistime the water conservation program, Beat thePeak, was initiated.

As is shown in Figure 5-10, between 1976and 1993 rates were updated every year. For av-erage water use customers, bills just barely keptahead of inflation. At least in part because thereal price of water stayed about the same, andincomes in County increased at a higher ratethan the rate of inflation, water use increased.In 1993, there was a significant increase in the

price of water, especially the summer rate. Pub-lic reaction, however, forced a redesign of therates and a decline in the real price of water inthe summer. The real (inflation adjusted) priceof water has declined since then.

Water providers must get approval tochange water rates. Municipal water utilitiesmust get approval from the city or town coun-cil. Changing the rates is much more difficultfor water companies that must get approvalfrom the Arizona Corporation Commission ().Going through this process is expensive be-cause of the legal fees involved and costs of arate hearing can easily reach hundreds of thou-sands of dollars, even for a small water com-pany. This is required even if a companydoesn’t plan to raise more revenue from cus-tomers, but just change the rate structure. This


54

Figure 5-9 The Beat the Peak Program tried many approaches tourge the public to restrict water use during peak hours.

Photo: Barbara Tellman.

discourages many companies from changingrate structures to promote conservation.

Charging More to Pay ForFuture Supplies

A more controversial way to change rates isto charge more in anticipation of the need toacquire a more expensive water supply in thefuture. The cost of developing and deliveringTucson’s new water supplies — CAP and treatedeffluent — are more expensive than pumpingand delivering groundwater. Some economistsargue that people now using the cheaper watershould help pay for the future costs of develop-ing the new, more costly supplies that eventu-

ally will be needed. Ac-cording to this theorywater costs should riseto build up a reserve forthe future. This wouldmake it fairer for futureusers who must use themore costly water, andthe higher cost wouldencourage conservationof the existing supply.This approach is rarelyadopted for many rea-sons. For one, it is not apolitically popular ap-proach. Also, it is virtu-ally impossible for aprivate water companyto acquire extra moneyto cover future coststhrough the ACC pro-cess. Municipal utilities

are often run on a cost of service basis, neithermaking a profit nor running a deficit. Accumu-lation of an unused pot of money would notfit this model, although some funds can be putaside for the future.

CONTRARY VIEW

Not all Tucson citizens are committed to awater conservation ethic. Some people do notbelieve a water shortage exists, especially nowwhen Arizona has more CAP water than it canuse and faces the prospect of California or Ne-vada claiming the state’s unused portion. Otherpeople believe they have a right to as much wa-ter as they are willing to pay for, to use as they

see fit. Some critics claim such people may in-dulge in excessive water use but, in response,they may claim theirs is an essential use of wa-ter. Not all people appreciate landscaping withlow-water use native plants; some prefer greenlawns all year long. While some people con-sider golf courses a recreational necessity or away to raise property values, others believe suchfacilities waste valuable water and benefit onlythe few who use them.

Some people are reluctant to save water be-cause they perceive conservation as a cynicalmeans to justify population growth. Such skep-tics argue the main reason business interestssupport conservation is to save water that thencan be used to enable more people to moveinto the area. In this scenario, conservation ef-forts may result in reducing existing water use,but a growing population would soon consumewhatever water savings are achieved.

AGRICULTURAL WATER USE

Agriculture has been the predominant userof water in Arizona in the 20th century. Sincethe 1940s, agriculture has accounted for about80 to 90 percent of Arizona’s water use. In theTucson area, agriculture’s share of water use inthe Upper Santa Cruz Basin (which excludesthe Avra Valley) was about 84 percent in 1940,shrinking to about 73 percent by 1951.

The general downward trend in agriculturalwater use has resulted mostly from a reductionin cropped acreage. Cropped acreage in PimaCounty reached a plateau in 1955 and re-mained fairly constant until 1975, at about50,000 to 60,000 acres. Irrigated acreage de-clined after 1975 as farmland was developed for


55

Figure 5-10 Tucson Water bill for average single family residentialcustomer, inflation-adjusted 1998 dollars.

Sources: Water Resources Research Center, Tucson Water.

urban use along the Santa Cruz Riverfloodplain, including the Marana area. TheCity of Tucson purchased over 20,000 acres offarmland in the Tucson area from the 1950s tothe early 1980s, taking that land out of agricul-tural production in order to use its water rightsfor municipal purposes.

After declining through the 1980s andearly 1990s, agricultural water use increased to132,700 acre-feet in 1997. Use in 1997 includes25,100 acre-feet of CAP water used in-lieu ofgroundwater under the groundwater savingsprogram set up by the State of Arizona (See dis-cussion below). Reasons for the increase in agri-cultural water use are not clear. Rules forparticipation in the groundwater savings pro-gram allow use of renewable water suppliesonly in place of groundwater that otherwisewould have been pumped. Other reasons forthe increase that have been cited include bettermarket conditions and the passage of the Fed-eral Agriculture Improvement and Reform Actof 1996. This act removed federal price supportprograms and increased pressure on farmers to

plant as many acres as possible to cover over-head costs.

Agricultural water use in TAMA is regu-lated under the Groundwater Management Actof 1980 (GMA). The GMA regulates agricul-tural water use in several ways. First, no new ag-ricultural land can be developed for irrigation.Second, farms are given a maxi-mum annual allotment ofgroundwater to be used for irriga-tion. This is based on the historicamount of irrigated acres on afarm in the five years before theGMA and an amount of water tobe used per acre, called a waterduty. This irrigation water dutywill be reduced over time as in-creasing water application effi-ciencies are required (See Chapter7 for more detail).

Farms using less than theirgroundwater allowance are givena credit for the difference betweentheir actual water use and thegroundwater allowance. These

credits are accumulated in a flexibil-ity account and can be used in fu-ture years, if needed, to meetconservation requirements. There isno limit to the number of flexibilitycredits that can be accumulated.

Annual groundwater allotmentswere set near the historic peak of irri-gated acreage; thus much moregroundwater than is needed is legallyavailable to farmers each year. Withirrigation efficiencies increasing onfarms and significant amounts offarmland out of production, many

farms have accumulated large flexibility ac-count balances. On average, TAMA farms wereusing 50 to 60 percent of their groundwater al-lowances. ADWR projects that, even as requiredirrigation efficiencies are raised to 85 percent,most farms will still accumulate credits. The ex-


56

IRRIGATION AREAIRRIGATEDACREAGE

1987-1995AVERAGE WATERUSE (acre-feet)

WATER SOURCES

Cortaro Marana Irrigation District 10,543 33,439 Groundwater, CAP, Effluent

Avra Valley Irrigation District 11,360 26,240 Groundwater, CAP

Farmers’ Investment Co. 5,909 28,026 Groundwater

Red Rock Area 3,843 n/a Groundwater, CAP

Table 5-2 Summary of water use in major irrigation areas in the Tucson AMA.

Source: Arizona Department of Water Resources, Draft Third Management Plan, Tucson Active Management Area, 1998.

Figure 5-11 Irrigated acreage in Pima County, 1900-1997.

Sources: Arizona Agricultural Statistics 1966 - 1997, Arizona Agriculture 1942 -

1965, Arizona Academy 10th Arizona Town Hall, 1967.

istence of large flexibility account balances hin-ders the ability of agricultural conservationrequirements to affect agricultural water use.

As shown in Figure 5-12, four main groupsof farms are clustered in three agricultural areasremaining within TAMA. Two irrigation dis-tricts are operating in TAMA: Cortaro MaranaIrrigation District (CMID), located north andwest of the Town of Marana, and Avra ValleyIrrigation District (AVID), located generallyjust south of CMID, southwest of the SantaCruz River. Irrigation also is occurring in what

is referred to as the Red Rock area, in the PinalCounty portion of TAMA. Farms within theFarmers Investment Company (FICO) nearGreen Valley account for most of the rest ofTAMA agricultural land. Agricultural water usein other areas of TAMA, such as the Tucsonarea, the Altar Valley and farmland in theArivaca area, accounts for less than three per-cent of total agricultural water use in TAMA.

The San Xavier (south of Valencia Road)and Schuk Toak districts (western Avra Valley)of the Tohono O’odham Nation have CAP al-locations, which may be applied to restore his-toric farmlands and add additional farmland.Projections show that about 5,000 acre-feet ofCAP water may be used on the San Xavier Dis-trict by the year 2005. The Schuk Toak Districtcurrently is developing a farm which is ex-pected to use 10,800 acre-feet of CAP water peryear by 2010. A pipeline to supply CAP waterto the San Xavier District is now under con-struction.

Cotton is the predominant crop grown inTAMA, accounting for about 75 percent ofplanted acreage. Other crops grown includewheat, barley, sorghum, alfalfa hay, vegetables,nuts, millet and lettuce. Pecans are the predom-inant crop grown at FICO.

The cost of pumping groundwater forTAMA farmers depends mainly on the depthto groundwater and energy costs. With accessto low-cost hydropower generated at HooverDam, CMID has about the lowest pumpingcost in TAMA. The district controls well pump-ing and supplies water to farmers at a cost of$30 per acre-foot, plus an annual assessment of$40 per acre for every acre in the district. Indi-vidual farmers within AVID have their own

wells and control water use decisions. Pumpingcosts for wells in the district were about $40 to$50 per acre foot in 1995, including operation,maintenance and repair costs. Average pump-ing cost for FICO wells was recently reportedto be $28 per acre foot.

To encourage farms to use renewable sup-plies such as CAP water the cost of such sup-plies needs to be comparable to the cost ofpumped groundwater. When originally offeredto irrigation districts in Arizona, CAP watercost more than pumped groundwater. As a re-sult, fewer irrigation districts than expectedsigned subcontracts for CAP water. Many irri-gation districts that did sign subcontracts faceda financial crisis, if not bankruptcy, until theState of Arizona offered incentives to increaseCAP water use by agriculture. The state offeredirrigation districts who had signed a CAP sub-contract a reduced price for the water in returnfor irrigation districts giving up their long-termright to use CAP water. Since none of the irri-gation districts in the Tucson AMA signed sub-contracts to use CAP water, they were noteligible for these favorably priced allotments ofCAP water.

TAMA farms, however, are eligible to useCAP water under another incentive programdesigned to encourage CAP water use. Underthe Groundwater Savings Facilities (GSFs), oth-erwise known as in-lieu recharge facilities, mu-nicipal water providers offer CAP water tofarmers at prices below the cost of pumpinggroundwater. Farms use this CAP water in lieuof groundwater that otherwise would have beenpumped. Municipal providers get credits forthis “saved” groundwater. The credits then canbe used in the future to offset groundwater


57

Figure 5-12 Irrigated acreage in TAMA.


pumping in efforts to meet state groundwaterpumping restrictions.

As is shown in Table 5-3, CAP water usethrough the groundwater savings program hasgrown from about 10,000 acre-feet in 1995 to25,000 acre-feet in 1997. CAP water usethrough GSFs continues to expand as new facil-ities are added and existing facilities are permit-ted to take more water. For example, CMIDused almost 10,000 acre-feet of CAP water as agroundwater savings facility in 1997 and has in-creased its state permit to take up to 20,000acre-feet per year of CAP water in the future. Agroundwater savings facility located withinAVID includes several farms. The AVID GSF ispermitted to take up to 12,513 acre-feet per yearof CAP water. FICO does not use any CAP wa-ter currently but is investigating the use of CAPand/or effluent. Use of CAP water at FICOcould occur through a GSF with a possible ca-pacity of up to 20,000 acre-feet per year. KaiFarms at Picacho, in the Red Rock area, con-verted from pecan trees to row crops in 1997,and irrigation with CAP water began under agroundwater savings project arrangement. TotalCAP water used at the Kai Farm at PicachoGSF in 1997 was 6,701 acre-feet. The facility is

permitted to take up to 11,231 acre-feet per yearof CAP water.

A small amount of treated effluent is usedon farms in the Tucson area. CMID purchasesan average of about 3,000 acre-feet of effluentper year from Pima County. The effluent is de-livered via a ditch from the Ina Road treatmentplant and is blended with groundwater for de-livery to farms.

Reducing AgriculturalWater Use

ADWR has goals for in-creasing water use efficiencyon farms. In 1980, water useefficiency in TAMA averagedabout 65 percent of water ap-plied. This means that the av-erage amount of waterapplied to crops was 35 per-cent greater than the calcu-lated water need for thosecrops after accounting for theconsumptive use requirementfor the crops, the amount ofprecipitation available for

plant growth, any additional water for specialneeds for crops — such as water needed for ger-mination of lettuce — and a leaching allowanceto prevent buildup of salts in the soil. The wa-ter use efficiency goal set for farms to reach bythe year 2000 is 85 percent efficiency. ADWRreports that many farms have already reachedthis goal, but other farming operations are notcertain whether this goal is attainable.

Flood irrigation on sloped fields is themost common irrigation method in TAMA.Some farms have saved water by laser-levelingtheir fields (a method of leveling and slightlysloping fields so that water spreads evenlyacross the field) or installing systems to pumpback water that accumulates at the end of thefield. Installation of drip irrigation systems isgenerally considered too expensive for irriga-tion in the Tucson area.


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GROUNDWATER SAVINGSFACILITIES

1993 1994 1995 1996 1997

BKW Farms 250 2,014 4,235 7,080 8,648

Cortaro Marana Irrigation District 2,650 0 5,902 9,581 9,746

Kai Farm at Picacho – – – 0 6,701

Total In-Lieu Recharge 2,900 2,014 10,137 16,661 25,095

Table 5-3 Water delivered to Groundwater Savings Facilities (acre-feet).

Source: Arizona Department of Water Resources, Draft Third Management Plan, Tucson Active Management Area, 1998.

Figure 5-13 Irrigation made it possible to grow a great varietyof crops in the desert.

ADWR also is requiring farms to maketheir distribution systems more efficient. Farmscan save water by lining their water distributioncanals with concrete or other materials. UnderADWR’s Second Management Plan, farms wererequired to either line all their canals or oper-ate their delivery systems to keep lost or unac-counted water at less than ten percent. Theagency reports that most of the largest irriga-tion districts in TAMA are meeting this re-quirement.

One of the biggest factors in reducing agri-cultural water use in the Tucson area has beenpurchase of agricultural land for subdivisionuse, especially in the Marana area. As munici-pal development continues in the Tucson area,more farmland will likely be converted.Whether or not the new land use will ulti-mately consume more water depends on manyfactors. In situations in which farmland is con-verted to apartment or business use, the totalwater use will probably be less than the agricul-tural use. In situations in which farmland isconverted to high-water uses such as golfcourses, total water use may be higher.

Another strategy for reducing agriculturalwater use is to buy agricultural land and the at-tached water rights to either convert rights tomunicipal use or permanently retire the waterrights. The City of Tucson bought many acresof farmland from the 1950s through the 1970s,and mining companies also purchased farm-land in the 1970s to secure water rights. TheGMA has provisions for state purchase of farm-land to retire agricultural water rights startingin the year 2006 but no source of funds hasbeen identified to accomplish this goal.

INDUSTRIAL WATER USE

Industrial water users in the Tucson AMAinclude metal mines, sand and gravel miningfacilities, electric power producers, dairy opera-tions, and other industrial users. As is shown inFigure 5-14, metal mining is the largest wateruser in the industrial sector, accounting for ap-proximately 70 percent of the total. classifiessome golf courses and other turf facilities withtheir own wells as industrial for legal reasons.All turf uses, however, were previously dis-cussed as municipal uses.

MiningFour active metal mines operate in TAMA.

The Cyprus Sierrita and Cyprus Twin Buttesmines are located adjacent to each other, southof Tucson and west of Green Valley. Water useat theses two mines totaled 26,165 acre-feet in1997. The ASARCO Mission Mine is locatedseveral miles north of the Cyprus Sierrita/TwinButtes mines. Copper and molybdenum aremined at two open pits and an undergroundmine at the site. A substantial amount of silveralso is recovered as a by-product. Water use atthe Mission Mine was 13,042 acre-feet in 1997.The ASARCO Silver Bell Mine straddles theTAMA boundary due west of Marana. Copperis mined in an open pit. Water use at the sitewas 575 acre-feet in 1997. On-site productioncapacity has been expanded with the mining ofa new deposit and the addition of a new pro-cessing plant.

Most mining in the Tucson AMA isopen-pit mining followed by milling and flota-tion. The ore extracted from the pits is crushedand delivered to the mill, where it is crushed

again and mixed with water to form a slurry.The slurry is discharged to flotation cells. Herechemicals are added that cause the materials tofloat to the surface for removal. Waste rock re-maining in the flotation cells is sent to thick-ener tanks. The solids settle in the tanks andthe water is recovered. The tailings mixture,which usually is 46 to 55 percent solids byweight, is transported via pipeline to the tail-ings pond. The tailings slurry is deposited inthe tailings impoundment with a spray, leavingstanding water in the impoundment which isskimmed off and recycled back to the mill. Atthe Mission Mine and the Sierrita/Twin Buttesfacility, approximately 30 percent of water sentto the tailings is recovered.

Copper also can be leached from piles ofcertain types of ore using sulfuric acid. Theleachate is then piped to another facility for re-covery of copper. Another form of leaching


59

Figure 5-14 1995 industrial water use,Tucson AMA.

Source: Arizona Department of Water Resources, Draft Third

Management Plan, Tucson AMA, 1998.

from buried ore, known as “in situ” leaching,has recently come into use. Both types of leach-ing use less water than milling and flotation,but “in situ” leaching has been applied only ona pilot scale in Pinal County, and both formsrequire the right kind of ore.

ADWR funded a study to analyze possibili-ties for additional water conservation in min-ing. Increasing the density of the tailings slurrywas one of the most effective steps available todecrease groundwater withdrawals. For everyone percent increase in the tailings density, 500to 800 acre-feet of groundwater can be saved

per year. Average tailingdensities may be able tobe increased from 48 per-cent to 50 percent atASARCO Mission andfrom 52 percent to 54percent at Cyprus Sierritaby installing smooth plas-tic piping to reduce fric-tion and by pumping theslurry instead of relyingon gravity. In addition,seepage of groundwaterunderneath the tailingsponds can be reduced bydepositing fine-grainedtailings on top of nativesoils before tailings aredelivered to the ponds.Evaporation of water intailings impoundmentscan be reduced by install-ing multiple decant tow-ers to more quicklydecant the water.

The 1997 study alsoexamined the possibility of using renewablesupplies instead of groundwater at the mines.The study found that the use of renewable sup-plies at the mines is unlikely to include efflu-ent, due to the great distance between existingeffluent lines and the mines. Use of CAP waterwas deemed theoretically possible, but severalobstacles currently prevent use of this watersource. First, the mines have the legal right topump groundwater, and groundwater is signifi-cantly cheaper than CAP water. While total wa-ter use at these sites in 1997 was 39,207

acre-feet, the mines have rights to withdraw atotal of 62,188 acre-feet of groundwater peryear. Mines were originally expected to useCAP water in the Tucson area, but no miningfacilities signed subcontracts for CAP water.The best incentive for mines to use CAP waterwould be if its price was lowered to equal thecost of pumping groundwater. This price ad-justment likely would have to come as a sub-sidy from other water users. The cost ofpumping groundwater, including energy andmaintenance costs, was reported to be $84 peracre-foot at the ASARCO Mission Mine and$163 per acre-foot at Cyprus Sierrita in 1997.

Another obstacle to mines using CAP wateris its quality. If mines use CAP water instead ofgroundwater, the process of recovering metalsfrom the ore would not be as efficient. Testsconducted by the mines show that use of 100percent CAP water resulted in declines in cop-per and molybdenum recovery. More study isneeded to assess the potential impact on recov-ery rates when using a blend of CAP andgroundwater.

Yet another obstacle to CAP water use isthe question of CAP delivery reliability. Minesneed water for ore extraction 24 hours a day,seven days a week. CAP water delivery interrup-tions would cause fluctuations in the quality ofwater delivered to the mill storage reservoirsand result in a need to readjust the rates atwhich chemicals are added to maintain mineralrecovery efficiencies. Emergency outages pres-ent the greatest problem in adjusting tochanges in water quality because of the lack ofadvance warning.

A final obstacle is that mines are concernedabout the spread of polluted water. By pump-


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Figure 5-15 Open pit copper mine. Photo: Barbara Tellman.

ing groundwater mines have created a cone ofdepression that confines polluted water to thearea near the mines.

Mining in TAMA is projected to remain atapproximately the current level into the nearfuture, and total water use is estimated to in-crease slightly to 47,500 acre-feet per year by2025. The level of future production and wateruse in the mining sector, however, is difficultto predict. The health of the mining sector ishighly dependent on the fluctuating price ofcopper and molybdenum and advances in min-ing technology. Proven reserves at CyprusSierrita are reported to be 20 years at currentproduction levels and extraction technology.Producers continue to add to capacity, such asthe expansion at Silver Bell Mine, but water useefficiency also is increasing.

Sand and Gravel FacilitiesThe approximately 15 sand and gravel facil-

ities operating in TAMA used 5,176 acre-feet ofgroundwater in 1995. This is projected to in-crease to 7,000 acre-feet per year by 2025. Mostsand and gravel facilities recycle much of thewater used for washing mined stream deposits.Facilities can save additional water by reducingwater use for dust control and other clean-uprelated activities. Sand and gravel facilitiescould theoretically use CAP water, effluent orpoor quality groundwater. Secondary effluentcould be an inexpensive and feasible alternatesupply. Because sand and gravel operations areable to pump groundwater at relatively lowcost, switching to CAP water would not be eco-nomical without a subsidy.

Other Industrial UsesOther industrial uses include water for elec-

tric power generation and dairy facilities. In1995, the electric power industry used 1,609acre-feet, and the only remaining dairy inTAMA used 73 acre-feet in 1995. Since littlepower is generated locally, electrical usage isnot expected to go up over time. Other miscel-laneous industrial users consumed 4,026 acre-feet in 1995. Cooling towers and large-scalepower plants may be able to switch to effluent.

RIPARIAN AREAS ANDWILDLIFE HABITAT

For many years official studies didnot recognize wildlife habitat or riparianvegetation as a legitimate use of water. Di-version from streambeds is what counted,whether for use by humans, cattle or to ir-rigate crops. The Santa Cruz Riverthrough Tucson once had enough waterto support cottonwood-willow forests andbosques of giant mesquite that providedhabitat for creatures such as muskrats,beaver, edible fish and wild turkey. All ofthese creatures are gone from the area to-day, as are most of the riparian forests.Human demand for water outweighed thevalues of flowing streams and riparianhabitat. In recent years, however, this atti-tude has begun to change. Proposals havebeen made to allocate a certain percentageof CAP water for establishing some ripar-ian vegetation along the Santa Cruz River,Rillito Creek and Cañada del Oro Wash.

Riparian Water NeedsA riparian area in our desert environment

needs a reliable supply of water year round(base flow), and it needs occasional springfloods. The base flow may sometimes be justbelow the surface. Spring floods are needed sothat seeds can germinate in the moist soil, thenbegin to extend their roots downward as theflood waters recede. Even in a natural system,spring floods don’t always set the stage foryoung trees to get started. In an artificial envi-ronment, such as the area along the Santa CruzRiver through Tucson, even if trees do get


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Figure 5-16 Riparian areas are vital to some 85percent of Arizona’s wildlife, including migrating

birds. Photo: Barbara Tellman.

started, they may not have enough base flow tosupport their continued growth.

If the groundwater is at the surface, a vari-ety of wetland plants might grow, such as cat-tails or rushes. As the water table drops, plantsneeding constant water are the first to die.Shrubs and trees can survive in areas wheregroundwater is available down to ten feet belowthe surface. Mesquite can survive in desert areaswithout a constant supply of water to the roots,but they grow into very large trees in areaswhere their roots can reach groundwater.Large mature trees have roots that can godown more than 50 feet to reach water.

If the water table is so far below thesurface that roots cannot reach water, theplants may still be able to survive if wateris available from other sources such aswastewater from a treatment plant. Down-stream of Nogales, for example, a rich ri-parian area survives on effluent from theNogales International Wastewater Treat-ment Plant. The effluent provides thebase flow that groundwater would haveprovided and normal variations in rain-fall provide the spring floods needed forseedlings. CAP water could also augmentflood water in this way.

Riparian Vegetation Water UseQuantifying how much water is used

by riparian vegetation is difficult. A ma-ture cottonwood tree can use a lot of wa-ter in the growing season, but uses verylittle when leaves fall in the winter. As aresult some people argue that if cotton-wood forests were cut down along streams

such as the San Pedro, more water would beavailable for human use. Others counter thatthis is only partly accurate, because trees andother vegetation perform important functions,some of which actually help to conserve waterin the region. For example, the roots of the ri-parian vegetation hold soil in place, helping tocontrol erosion. Vegetation slows rushing floodwaters so that more water remains in the imme-diate area for recharge. Finally, vegetation pro-vides shade, keeping the water temperature

lower than would be the case in the blazingsun, reducing evaporation. The overall impactof tree removal on water resources available forhuman use is a debated issue, in need of fur-ther research.

Establishing Riparian Areas &Creating Wetlands

Water can be used to create wetlands offthe stream or to establish vegetation and habi-tat in the stream channel itself. A stream, how-

ever, needs more than water to form ahealthy riparian area. A stream in its nat-ural state tends to meander and over timechanges its course over a wide floodplain. Cottonwoods may germinate alonga new channel, while mature cotton-woods still grow along an old channel.Terraces tend to form and different vege-tation is found on successively higher ter-races. These conditions often are notpossible in a populated area such asdowntown Tucson, where buildings existalong the banks, and flood control struc-tures constrain the river within a narrowchannel.

Where the stream channel is in a rel-atively natural state, as is the case withmany washes, restoration does not posegreat difficulties. The addition of watermay be all that is needed. The RillitoCreek at Craycroft Road, for example,had a lush cottonwood and walnut forestuntil very recent times. Pumping has de-pleted the aquifer to the point that thetrees are stressed. Cessation of pumpingwould probably very quickly lead to res-


62

Figure 5-17 Hikers enjoy a visit to Pima County’sCienega Creek Preserve. Photo: Barbara Tellman.

toration of a vigorous riparian habitat. Simi-larly, the Tanque Verde and Pantano washeshave areas where pumping has lowered the wa-ter table, but conditions are still good for resto-ration if pumping levels decline significantly.When water was added to the Santa Cruz Rivernorth of Nogales, the riparian vegetation cameback quickly. The river in that area is shallow,and a broad flood plain stretches out on bothsides of the river where flood waters can spreadout onto farm land and meander in changingchannels. The Santa Cruz River between ElCamino del Cerro and Ina Road has a riparianhabitat dominated by willows. Effluent fromthe Roger Road Wastewater Treatment Plantwaters this area.

Where the stream channel is deeply incised,however, and/or where the banks have been sta-bilized to prevent erosion, establishing a ripar-ian area is much more difficult. The SantaCruz River, through the downtown Tucsonarea, is not only deeply incised, but has soil ce-ment on both sides of the river, keeping the wa-ters within steep banks. This part of the river isno longer conducive to spontaneous develop-ment of cottonwood willow forests merely bycreating a flow. In the San Xavier District, theU.S. Bureau of Reclamation built a rock struc-ture to encourage the growth of riparian treeswithin the channel along one side of the river,even though the banks are steep and subject toerosion. Downstream of the downtown area, ef-fluent from the wastewater treatment plantssupports a small riparian area, that is inter-rupted, however, by bank protection. TheRillito Creek, similarly, is incised and has bankprotection along much of its length. The best

possibilities for riparian habitat are probably inthe upstream areas and along certain washes.

Tucson Area RiparianRestoration Projects

A number of water-based projects whichhave riparian restoration benefits are being de-veloped or considered in the Tucson area.

Many of these projects involve one or moregovernmental entities and are included as partof the City of Tucson’s “Multiple Benefits Wa-ter Projects” or County’s “Sonoran DesertConservation Plan.” Figure 5-18 shows a num-ber of the current and proposed projects, ex-tending from Pima Mine Road to Marana andfrom Avra Valley to Tucson’s east side. Insome cases proposals are being developed


63

Figure 5-18 Projects which include riparian and wildlife benefits.

Sources: Pima County, City of Tucson.

jointly by the city and county and are includedin both plans.

The county’s water-related restoration pro-jects include a recharge project along the SantaCruz River in Marana that will enhance the ri-parian area by using treated wastewater. A pro-posed project will restore a higher water tablealong the Rillito. A detention basin along Ar-royo Chico at Park Avenue is to provide urbanwildlife habitat through alteration of the cur-rent flood control structures. Additionalproposed projects include restoration of ripar-ian habitat along the Cañada del Oro usingCAP water.

Tucson’s Multiple Benefit Water Projectsinclude a number of water-based projects which

would provide recreational opportunities, wild-life habitat as well as recharge of groundwater.

Four of the recharge projects have essen-tially no restoration component (Central AvraValley, Pima Mine Road, Rillito Recharge Pro-ject, and Santa Cruz Managed UndergroundStorage Facility). The Sweetwater Wetlands,which has a rich habitat, is a constructed wet-land located a slight distance from the SantaCruz River channel. The Atturbury Project usesreclaimed effluent for riparian habitat restora-tion. The Kino Sports Park involves a lake in-corporated into a golf course area, while theSilverbell Driving Range Project involves asmall constructed wetland to treat restroom wa-ter. The Tucson Airport Remediation Project isa pollution remediation facility, and its water

could be made available for riparian habitat de-velopment along the Santa Cruz River. How-ever, community approval would be neededand legal constraints surmounted. Three pro-jects are primarily stream restoration (RillitoCreek, Santa Cruz River, and San Xavier). TheRio Nuevo Project near downtown Tucson isalso part of this plan.

If the city decides to dedicate a portion ofits CAP allocation to habitat establishment,long-term community support is needed. Anincrease in population could eventually justifyusing the entire CAP allocation to serve humanneeds. Whether the Tucson community wouldagree to this reallocation or would insist that aportion of the city’s CAP allocation continueto be used to maintain riparian areas is unclear.


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TUCSON WATER QUALITY

For the most part, the quality of the ground-water in the Tucson area is excellent, al-though problems exist in a few areas. Some

water quality problems such as radon and hard-ness are naturally occurring, but most problemsare the result of human activity. In most cases,where pollution occurs, the level is very lowand does not constitute a health problem. Inseriously contaminated areas, commercialdrinking water wells with dangerous levels ofcontamination are not in use, but privatewell-owners may still be drawing from contami-nated sources. Some of most serious pollutionproblems have been designated as federalSuperfund (CERCLA) or state Water QualityAssurance Revolving Fund (WQARF) sites andsome of those problems are being mitigated.The laws and regulations that help protect ourwater are described in Chapter 7.

GROUND-WATERPOLLUTION

TCE ProblemIn Tucson a few

incidents of healthproblems have oc-curred due to waterpollution. The bestdocumented incidentinvolves the occur-rence of a plume oftrichloroethylene(TCE) in groundwa-ter that extendsnorthwest from theTucson InternationalAirport. In 1981, anunusual cluster ofhealth problems was

65

Chapter 6ENSURING SAFEDRINKINGWATER

Our health and well being depend upon having a supply of safe drinking

water. In much simpler times this might have meant having a good well

or a stream nearby. Today the issue is a lot more complex. To supply a

large urban population we dip into various water sources: surface water,

groundwater and imported water—e.g. CAP water—each with its own water

quality concerns. Also we are more aware of different contaminants in water

and the need to control or remove them to ensure the safety of our water supply.

(If early settlers from those simpler times knew what we know about microbial

contaminants they might have been wary of their wells and the nearby streams.)

In response to this situation, various water treatment methods have been

developed. We are sufficiently privileged that our water quality concerns focus not

only on public health matters, but also consider the aesthetic characteristics of our

water supply; i.e., its taste and odor.

Figure 6-1 Maximum extent of the TCE plume.

Sources: Pima County, U.S. Environmental Protection Agency.

identified in the area west of the airport. Testsindicated a high level of TCE in the water.Health officials investigated to determine if aconnection existed between the polluted waterand the reported diseases. They found suffi-cient evidence to cause Tucson Water to shutdown wells in the area and supply residentswith water from other parts of the system.

Officials then took on the issue of what todo about the contaminated area. They first hadto determine who was responsible for thecleanup and what methods were best to use.Most of the aircraft companies responsible forthe problem had ceased operations years earlier.Ultimately, Hughes Aircraft (since purchased

by Raytheon) built a treatment plant to dealwith the problem beneath its property. As a re-sult of a consent decree and agreement, theTucson Airport Authority, U.S. Air Force andothers built a treatment plant for the waterdowngrade from the airport. Operated by Tuc-son Water, the Tucson Airport RemediationProject (TARP) is located on the east side of theSanta Cruz River near Irvington Road. Nine ex-traction wells and five miles of transmission

mains transport water to the plant. TARP hasthree 35-foot air-stripping towers with air emis-sion controls that remove the volatile com-pounds to avoid air pollution problems. Theplant also disinfects the water and adjusts itspH. Treated water is tested weekly, and no de-tectable amounts of TCE have been found.TARP costs $780,000 annually to operate.Raytheon, U.S. Air Force, McDonnell Douglas


66

Sources: Pima County Department of Environmental Quality, Pima County, Pima Association of Governments.

Figure 6-2 Landfills and major identified hazardous plumes in groundwater.TESTING FOR POLLUTANTS

Testing for a full range of pollutantsis costly because different pollutantsmust be tested by different methods,and the amount of pollutant to be de-tected is generally very small, perhaps aslittle as one part pollutant in a billionparts water. Routine water testing is gen-erally conducted for common pollut-ants such as coliform bacteria, nitrogenor sulfur compounds. Where reasons ex-ist to suspect other pollutants such asTCE, tests for those pollutants becomepart of the testing routine. There arenow well over 230 priority pollutantsfor which water supplies must be testedat least once a year. Standardized testingis unavailable for many uncommon po-tential pollutants.

Corp. and the Tucson Airport Authority paythe cost of operating the facility.

Officials also had to decide what to dowith the treated water. Under a Consent Agree-ment, approved by EPA, Tucson Water blends

the treated water with other water anddistributes it in the city water system. Thetreated water currently goes to customers down-town, and the near northwest side. Althoughthis water meets all EPA drinking water stan-

dards, some customers objected to its use. In1995, when voters approved the Water Con-sumer Protection Act to limit the city’s use ofCAP water, they also restricted the city’s use ofthis treated water since it originated from a“polluted source.” Tucson Water, however, stillmust meet the conditions of the legally bindingEPA consent agreement and continues to putthe treated water into the municipal system un-til a solution is worked out.

Some customers are very wary of drinkingwater that once was contaminated with TCE,eve if it now meets drinking water standards.Several options exist for using the treated wateras part of the city’s drinking water supplies,subject to approval by the EPA and other par-ties to the consent agreement, and subject to in-terpretation of the Water Consumer ProtectionAct. These include releasing it into the SantaCruz River; using it to create artificial wetlands;or injecting it underground with injectionwells. Others argue that after the expense of pu-rifying the water, it is wasteful to pollute itagain by discharging it into the river. They ar-gue that since the city does not have to pay totreat the water it is essentially free water. Also,they argue that the treated water is actually thecleanest water in the city system and the mostfrequently tested.

Pollution From LandfillsAnother identified source of groundwater

pollution is old landfills built before currentregulations about landfill construction were inplace. Some historic wildcat landfills pose prob-lems in determining what actually was dumpedthere. Officials are concerned about such wastes

Chapter 6. Ensuring Safe Drinking Water

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CONTAMINANT LOCATION SOURCE

Sulfates Green Valley Mining

Nitrates Green Valley Natural

Radon Tucson, various locations Natural

Nitrates Santa Cruz River Agriculture, Sewage Effluent

Chromium Near downtown Manufacturing

PCE and TCE Broadway/Pantano Landfill

Petroleum Davis-Monthan Leaking Fuel Tanks

23 VOCs El Camino del Cerro Landfill

VOCs/Metals ESCO - Tucson Hazardous Waste Site

VOCs (PCE, TCE andothers)

Los Reales Landfill Landfill

TCE, PCE, Freon andothers

Miracle Mile, Silverbell JailAnnex

Landfill

Diesel, PCE, TCE andothers

Mission LinenDry Cleaning, LeakingUnderground Storage Tanks

TCE and chromium Airport Solvents in Aircraft Cleaning

Chromium, TCE andothers

Hughes (Raytheon) Waste Disposal

Arsenic Various Natural

PCE - perchloroethylene; VOC - volatile organic compounds; TCE - trichloroethelyne

Table 6-1 Identified groundwater contamination sites in Pima County.

Source: Arizona Department of Environmental Quality, Arizona Water Quality Assessment, 1996.

as pesticides, dry cleaning solvents, paints ordiscarded car batteries containing lead. Also,decaying organic material can release methane.Officials are most concerned about landfills lo-cated near riverbeds where flood waters canleach materials out of the landfills into the wa-ter table. Recharge projects must not be locatedin such areas.

One significant landfill pollution site is onTucson’s east side, along the Pantano Wash be-tween Broadway and Speedway Boulevard. Thisis the location of a 130-acre landfill that the

city and county used from 1959 to 1974.Concern exists that landfill gases may be mov-ing either in solution or by diffusion and pres-sure gradients toward the water table. A plumeof contaminated water is moving westward atabout one and half feet per day. This rate in-creases when the demand for water is high be-cause, as the nearby five wells pump water, thecontamination plume moves forward. Thesefive wells, however, are only used as a last re-sort when summer demand is high. The waterfrom these wells meets water quality standards.The concern in this area is that the plumewhich contains PCE will migrate towards acone of depression in an area where TucsonWater has active wells. If recharge were to oc-cur along or near the Pantano Wash in thatarea, the active wellfield could become contam-inated.

Other PollutionA large area beneath the downtown area is

contaminated with petroleum products from avariety of sources, probably largely from activi-ties connected with the railroad. Some other ar-eas also have petroleum contamination, mostlyfrom old leaking underground storage tanks,which the state now regulates. Water is notpumped from these polluted sources.

WASTEWATER TREATMENT

Treatment PlantsMost of the sewage generated in the metro-

politan area is transported by gravity throughpipes to two large Pima County wastewatertreatment plants, located along the lower Santa

Cruz River at Roger and Ina roads. Solids areremoved and, through a bacteriological process,disease-causing microorganisms are reduced. Af-ter the treatment process is complete, thewastewater is disinfected, with most of it re-leased to the Santa Cruz River. EPA maintainsstrict standards for the quality of the water re-leased, and the water is frequently tested. Thetreatment process is not designed to handletoxic materials; in fact, some toxics can makethe treatment process less effective by killinghelpful bacteria. Pima County has a pretreat-ment program for businesses that producetoxic wastes. The program requires such busi-nesses to treat or reuse hazardous substances,rather than releasing them into the sewers.Many people, however, are unaware of theproblems that materials such as oil and paintremover can create and flush them down thedrain. Pima County attempts to educate indi-viduals about proper disposal of hazardous ma-terials and has a program to collect householdhazardous materials.

Some of the wastewater from the RogerRoad Treatment Plant receives tertiary treat-ment in a City of Tucson facility and distrib-uted for use on golf courses and other turffacilities. Tertiary treatment involves treatmentthrough sand filters or soil and additional dis-infection. Part of the effluent is taken toSweetwater Wetlands, an artificial wetland Tuc-son Water completed in 1998. This wetlandadds another layer of treatment before discharg-ing the water to recharge basins. Artificialwetlands have become increasingly popular inArizona in recent years as they serve not onlyto treat the water, but also provide wildlife hab-itat and recreation. A small amount of


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ESTABLISHING RISK LEVELSFOR POLLUTANTS

Of all the chemicals produced in theworld today, only a fraction have beenstudied for their possible harmful ef-fects. Also, each year more new chemi-cals are produced, although their effectsmay not be understood. EPA has stud-ied only the more common chemicals,especially pesticides and herbicides,mainly concentrating on whether theycause cancer or birth defects.

A great deal remains unknown.Meanwhile we confront a dilemma : Dowe take a risk on the assumption that asubstance has not been proven harmfulor do we avoid substances that lack com-pleted studies of their potentially harm-ful effects? Do we assume that any levelof a harmful substance is to be avoidedor do we set acceptable limits that allowa limited amount of the substance to bein our water?

wastewater is taken from the Ina Road plant foragricultural use and to irrigate the county’s Ar-thur Pack Golf Course.

Some areas, such as Green Valley, are lo-cated far from major treatment plants and havetheir own small facilities, almost all of whichare operated by Pima County. Other areas,such as Marana, are downhill from the majortreatment plants. Their sewage must either betreated on-site or pumped uphill for treatment.A few areas have privately constructed smalltreatment plants, with treated water applied tosuch uses as golf courses.

Septic SystemsAn estimated 10 to 15 percent of homes in

the Tucson area have their own septic tanks. Al-though most septic systems are in rural areas,some neighborhoods within city limits also areserved by septic systems. A county permit is re-quired to install the system, and the applicantmust show that the soils are appropriate forpercolation of water.

A well-designed, installed and maintainedseptic system can be highly effective in treatinghousehold wastewater. Conversely, a poorly de-signed, installed or maintained system can con-tribute to local groundwater pollution and canbe a health hazard. This is especially true in ar-eas with shallow groundwater. Not much infor-mation is available to determine if septic tanksin the Tucson area are in fact causing pollutionproblems. Evidence exists, however, that septicfields often impact drinking wells in rural areasof the state.

A traditional septic system consists of aseptic tank — which receives all of the waste

water from sinks,toilets, tubs,etc.—and adrainfield.Wastewater firstcollects in thetank, where sol-ids are allowed tosettle and breakdown throughnatural bacterio-logical processes.The liquid in thetank drains intoa series of perfo-rated pipes fromwhich it perco-lates throughgravel, sand andother permeablematerials. As theliquid drainsthrough the soil, remaining pathogens are fil-tered out and broken down by bacteria andother organisms in the soil.

Exceeding the capacity of the septic systemis one of the most common ways systems fail.High water-use appliances and leaky faucets cancause problems, as can heavy rains. If the soilsare constantly saturated, the efficiency of themicrobial activity is reduced. Other situationsthat result in septic problems include failure toexpand the septic system when the house itserves is expanded. Even short-term stressessuch as visitors can overload a septic system.

Though an overloaded system may show it-self in slow drains or sewage backups, a failingsystem may simply result in incomplete treat-

ment of the waste. Viral contamination, and ni-trate and phosphate “plumes” can jeopardizenearby wells. This is particularly troublingsince many of the Tucson homes on septic sys-tems also have their own drinking wells.

Failure to have settled solids in the tankpumped out every few years can let solids passto the drainfield, clogging the system. Addi-tional concerns include; soil compaction fromvehicles driving over the drainfield; commonhousehold chemicals such as toilet bowl clean-ers killing the microbes responsible for break-ing down the waste; and lint from washingmachines failing to settle in the tank, and thenclogging the drain pipes. A further concern isseptic tank owners adding solvents to dissolve


69

Figure 6-3 Part of a Pima County wastewater treatment plant.Photo: Barbara Tellman.

plugged leach fields. This putsharmful chemicals into the soil.

CENTRALTREATMENT VS.INDIVIDUALSYSTEMS

Centralized treatment gener-ally offers better control overwater quality than small or indi-vidual systems. Centralizationalso offers more opportunitiesto reuse or recharge wastewateror for recharge, although insome areas leachate from septictanks may help recharge thegroundwater. In the past, thecounty has had problems withsmall privately owned treatmentfacilities installed as part of asubdivision deteriorating oncethe subdivision is complete. Lo-cal policy discourages such facil-ities. On-site use of wastewater,however, can be an efficient wayof reducing groundwater pump-ing, without the costs of build-ing new pipelines and pumpingthe treated water to an outsidefacility.

HEALTH RISKS OFVARIOUS POLLUTANTS

Water pollution can cause a wide range ofhealth problems. Some of these problems show

up within days or weeks after contaminated wa-ter is consumed (e.g., dysentery) while othersmay take years to develop (e.g., cancer) and stillothers appear in the next generation (e.g., birthdefects). Cause and effect is more readily deter-mined when the problem appears shortly after

the water is used. When the problem surfacesafter a long period of time, cause and effect ismore difficult to establish. This is especiallytrue in our mobile society, with people develop-ing a disease at a location other than wherethey or their parents drank the contaminated


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DISINFECTANT EFFECTIVENESS PROBLEMS HEALTH CONCERNS

ChlorineHighly effective, but not aslong lasting as chloramines

In gaseous form can behazardous; odor and tasteproblems

Byproducts (THMs) maycause health problems

ChloramineRetains residual in largedistribution systems

Nitrification can lead toloss of residual

Hazardous to fish; shouldnot be used in kidneydialysis process; producesbyproducts with unknownhealth effects

Chlorine dioxideMainly used for taste andodor control

Produces inorganicbyproducts with unknownhealth effects

OzoneHighly effective for verycontaminated water, butdoesn’t leave residual

Energy-intensive/costlyProduces byproducts withunknown health effects

Ultraviolet radiationEffective, but doesn’t leave aresidual

Equipment has technicallimitations

Not effective against somepathogens

Reverse osmosis (RO)

Can be effective in removingpathogens and minerals, butgenerally requirespretreatment

Generally very costly;produces brine that mustbe disposed of and this canwaste water

None identified

Nanofiltration

Can be effective in removingpathogens and minerals, butgenerally requirespretreatment

Generally very costly;produces brine that mustbe disposed of; mostlyunproven in large-scaleapplications

None identified

Table 6-2 A summary comparison of ways of treating drinking water.

water. Appendix B lists the major pollutantsregulated by EPA under the Safe DrinkingWater Act and their possible health effects.

Providing Safe WaterMost water providers throughout the na-

tion treat their drinking water in some manner.The common methods are described below.Tucson Water chlorinates most of its water, pri-marily to provide protection as water flowsthrough pipes and reservoirs. Water providerssuch as Metropolitan Domestic Water Improve-ment District (Metro Water) and Flowing Wellsalso chlorinate their water to prevent diseasescaused by microbes. Since groundwater, whichis relatively free of pathogens and other harm-

ful substances, is the main source of drinkingwater in the area, the use of chlorine has beenadequate to protect health. Because CAP wateris from the Colorado River, a surface watersource, more extensive treatment will beneeded. Filtration and disinfection is requiredof all surface supplies or groundwater under in-fluence of surface water. More opportunities ex-ist for contaminants to get into open bodies ofwater than into groundwater.

Water treatment, which is necessary to pre-vent diseases such as cholera and dysentery,may cause health problems, mainly because ofcertain byproducts. EPA has become concernedabout some of the byproducts of various disin-fection processes and is currently funding re-

search to determine the possible extent that by-products may cause health problems.

Water treatment can serve five very differ-ent functions:

• Remove disease-causing microbes(disinfection);

• Remove toxic materials such as TCE;• Reduce corrosivity;• Reduce hardness or TDS;• Improve taste, odor or appearance.

Each water quality problem is very differ-ent and must be solved by different treatmentmethods. When determining appropriate treat-ment for CAP water, each problem must be ex-amined separately. In some cases a singletreatment method will deal with more thanone problem, but in most cases each type ofproblem requires a different solution.

Filtering Out ParticlesFiltration/flocculation, which removes sus-

pended particles from the water, is basic tomost forms of treatment. Filtered particles in-clude clays and silts, natural organic matter,precipitants from other treatment processes,iron and manganese and microorganisms. Fil-tration clarifies water and enhances the effec-tiveness of disinfection. Filters may be made ofa variety of materials, including sand, anthra-cite, aggregate or activated charcoal. Before fil-tration, a flocculation agent is added to causeminute particles in the water to coagulate intolarger particles to enhance filtration.


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CORROSION

Corrosion of a metal pipe is a process that involves primarily oxygen gas and the spon-taneous flow of electricity. Salts found in water have a secondary role in this process. Oxy-gen gas (O2) is found in small concentrations in water (4-9 mg/l), as well as in theatmosphere (20 percent by volume). Both Tucson groundwater and CAP are well oxygen-ated waters, though CAP has higher levels of dissolved oxygen. We can explain metal corro-sion by the fact that most metals are very good conductors of electricity and that they havea natural tendency to want to react with oxygen. During the corrosion process oxygen mol-ecules combine with electrons from the metal pipe and acid from the water to form watermolecules. The process results in the formation of metal oxides (rust in the iron pipes),which is soft, reddish-brown and has a metallic taste. In essence then the metal pipe dis-solves during the corrosion process.

Metal pipe corrosion can start on both sides of a pipe and often does. Poorly protectediron pipes that are buried in wet or waterlogged areas can corrode faster from the outsidethan from the inside.

Salts and alkalinity can either accelerate or inhibit pipe corrosion by forming scale (cal-cium carbonates) that limits the contact of oxygen with the metal surface or by dissolvingthis protective scale, as previously described.

REMOVING DISEASE-CAUSING MICROBES

Chemical DisinfectionWater is usually disinfected before it enters

the distribution system to ensure that danger-ous microbes are killed. Further, if the watertravels a distance to the customer or is storedfor a period of time in system reservoirs, thedisinfectant must remain effective long enoughto prevent disease. Chlorine, ozone, and chlor-amines are most often used for initial disinfec-tion because they are very effectivedisinfectants. A small amount of chlorine is of-ten added at the end of the process to retaindisinfection.

Chlorine has been used throughout thiscentury for disinfection of drinking water toprotect public health from diseases caused bybacteria, viruses and other disease causing or-ganisms. Chlorine is highly effective and hasbecome the most widely used disinfectantthroughout the world since its introduction inthe late nineteenth century. The decline of ty-phoid and cholera in the twentieth century is adirect result of chlorination of drinking water.While chlorine is effective, there are drawbacksto its use. These include odor, which customerscan sometimes detect. Chlorine tends to dissi-pate in air (which is why swimming pools mustbe repeatedly chlorinated) and does not remainstable in the distribution system for long peri-ods of time. Also, when used to treat water,chlorine can react with organic substances toform trihalomethanes (THMs) which are toxicdisinfection byproducts. Further, when storedor transported as a gas (the usual procedure for

large treatment systems) chlorine can be highlytoxic if accidentally released. Some water com-panies have switched to other forms of disinfec-tants because of these problems.

Chloramines, the monochloramine formin particular, have been used as disinfectantssince the 1930s. Chloramines are produced bycombining chlorine and ammonia. Chloramine

is a weaker disinfectant than chlorine, but ismore stable, thereby extending disinfectant ben-efits throughout a water utility’s distributionsystem. In fact, the primary use of chloramineis as a secondary disinfectant for maintaining adisinfectant residual in the distribution system.Chloramine is not as reactive as chlorine withorganic material in water, and therefore pro-


72

SALINITY, HARDNESS AND ALKALINITY

The mineral content of water is referred to as Total Dissolved Solids (TDS), reported inmg/L. (Mg/L is similar to parts per million.) Total Dissolved Solids are also commonly re-ferred to as “salinity.” This is somewhat misleading, however, as not all the salts found inthe water are table salts. The TDS measurement includes common elements such as so-dium, calcium, magnesium, chloride, sulfate, and bicarbonate that are combined withforms of sulfur and carbon with oxygen. Thus, TDS includes all the dissolved constituentsof other minerals such as table salt (NaCl), gypsum (CaSO4⋅2H20) and calcium carbonate(CaC03).

Hardness refers to the concentrations of calcium and magnesium ions, but is usuallyreported in mg/l of CaC03. Water hardness is linked to scale formation and the reducedcleaning efficiency of soaps.

Alkalinity, also usually reported as mg/L of CaC03, refers to the amount of carbonatesand bicarbonates present in the water. Alkalinity helps control the pH of water. In naturalwater carbonates and bicarbonates (related to atmospheric carbon dioxide gas) are the ma-jor constituents of alkalinity. These naturally occurring chemicals help control the pH ofwater between 7.5 and 8.5. If acid is added to water the alkalinity helps neutralize the acidwithout significant change in pH (Alka-seltzer effect). In natural waters moderate alkalin-ity is beneficial, since it is composed of carbonates that can combine with calcium. Cal-cium carbonate forms hard stable coatings (caliche-like) inside pipes and helps control(inhibit) corrosion. However, excessive calcium carbonate scale formation can eventuallyclog pipes, particularly in water heaters and other appliances (e.g., evaporative coolers) sus-ceptible to scale formation. CAP water has about 2.5 times the hardness of Tucsongroundwater, but CAP alkalinity is about 10 to 20 percent lower. Therefore, the ability ofCAP water to form scale may be slightly lower than that of Tucson’s groundwater.

duces substantially lower concentrations of dis-infection byproducts in the distributionsystem. Because the chloramine residual ismore stable and longer lasting than free chlo-rine, it provides better protection against bacte-rial regrowth in systems with large storagetanks and dead-end water mains.

Chloramine, like chlorine, is effective incontrolling biofilm, which is a slime coating inthe pipe caused by bacteria. Controllingbiofilms also tends to reduce coliform concen-trations and biofilm-induced corrosion ofpipes. Because chloramine is not as reactive aschlorine with organic compounds, fewer tasteand odor problems occur.

OzonationOzonation is the process of feeding ozone

into a water supply for the purpose ofdecolorization, deodorization, disinfection andoxidation. Ozone, a form of oxygen, is themost powerful disinfectant, but it is not effec-tive in controlling biological contaminants inthe distribution pipes because it does not havea long-lasting residual. Ozonation destroys bac-teria and viruses and requires a shorter time pe-riod to treat water than most other watertreatment methods. Ozone, a reactive gas, ismade by subjecting oxygen to high electricalvoltages. Ozone’s reactive nature allows it toreadily react with and break up many organic

compounds and kill bacteria and other organ-isms in the water supply. On-site production ofozone is energy-intensive. Ozone treatment isbecoming more common in the United Statesas questions arise about disinfection byprod-ucts. Ozone has been widely used in Europe for100 years.

Membrane FiltrationMembrane filtration is a relatively recent

development. Water is forced through mem-branes with small pores, and anything largerthan the pore size is filtered out. Along with re-moving materials such as minerals, membranefiltration also can be used for disinfection.


73

Many people buy home water treatment systems to further purifyor soften their water. Others use bottled water for drinking. What arethe choices?

• Water softening Soft water can be obtained with reverse osmosis(which also reduces TDS). Ion replacement systems (also called watersofteners) usually replace Ca and Mg with Na or K ions. Note that ionreplacement does not change the overall TDS of water appreciably.Note also that soft water with high TDS should not be used to irrigateplants. Since soft water is mostly desirable for washing purposes, an en-tire water system does not have to be connected to the water softener,possibly just the hot water line. Added salt in the water can be danger-ous for people on low salt diets.

• Removing pollutants People concerned with synthetic organic pol-lutants such as pesticides and solvents (TCE) in the water can installactivated charcoal or other types of filters on their drinking water taps.These systems work effectively if properly maintained, but bacteria canaccumulate if the systems are not cleaned regularly. In order to removesome pollutants such as lead and mercury, ion exchange filters are nec-

essary. Usually these systems are unnecessary in the Tucson area be-cause our water already meets all federal pollutant standards.

• Improving taste If the taste of water is a problem, a person caninstall filters as described above or can buy bottled water. While gen-erally of good quality, bottled water is not regulated by any govern-ment agency and the quality may be no different from tap water – infact, the water may be bottled tap water. Taste is a subjective matter,and some people have definite preferences in the brand of bottledwater.

One alternative to increased treatment of all city water is for in-dividuals who want different quality water to use in-home water sys-tems or bottled water. Everyone then is not charged extra for waterthat will more than meet federal standards. This approach is used inthe Yuma area where a high percentage of people have water soften-ers and buy bottled water. One argument against this approach isthat more affluent citizens would tend to have greater access to thesestrategies.

WHAT ABOUT IN-HOME WATER TREATMENT?

Four major types of membrane filtrationsystems are in use: reverse osmosis (RO);nanofiltration (NF); ultrafiltration (UF); andmicrofiltration (MF). The main difference be-tween the four types is the pore size of themembrane. This influences the amount of en-ergy needed to force the water through themembrane. The membranes must be cleanedperiodically. The smaller pore membranes re-quire the most cleaning (backwashing) which is

an energy-intensive process and wastes asignificant amount of water. (See the section ondesalinization below for further discussion ofRO and NF.)

• RO has the smallest pore size and removesa great variety of materials from the water,from salts to organic materials and very smallmicrobes. The water to be filtered must bepretreated to prevent pore clogging. In addi-tion, the concentrate of materials removed by

the filter is highly saline, causing loss of avail-able water as well as disposal problems. Thisprocess is not primarily used for disinfection,although disinfection is achieved in the processof desalting water.

• NF has larger pores than RO and removes,pathogens, organics and some salts. Like ROthe process requires pretreatment of water withchemicals or a sand-based system. NF has not


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WATER QUALITYCONSTITUENT

TUCSONWATER AVRAVALLEY WELLS

TUCSONWATERPRODUCTIONWELLS

RAW CAPWATER

SECONDARYEFFLUENT

RECLAIMEDWATER

EPADRINKINGWATERSTANDARDS

Sodium (mg/l) 41.0 40.1 96.7 112 122 None

Fluoride (mg/l) 0.39 0.36 0.425 0.80 0.93 4.0 (MCL)

Total DissolvedSolids (mg/l)

210 282 611 547 655* 500 (SMCL)

Hardness (as CaCO3)(mg/l)

84 129 266 141 217 None

Alkalinity (asCaCO3) (mg/l)

124 129 105 229 222 None

pH 8.1 8.0 8.12 7.35 7.0 6.5-8.5 (SMCL)

TotalTrihalomethanes

No Data <5.0 <1.83 <3.24 <11.4 100 (MCL)

* Reclaimed water includes groundwater recovered from the Sweetwater US&R Facility. Ambient groundwater is high in TDS.

MCL—Maximum Contaminant Level (EPA Primary Standard) SMCL—Secondary Maximum Contaminant Level

Table 6-3 Comparison of source water quality to federal standards. The figures are averages.Actual quality may vary at different times and places.

Sources: Adapted from Regional Recharge Committee, Technical Report, Arizona Department of Water Resources, Tucson Active Management Area, 1996.

been used commercially on a large scale fordrinking water.

• UF has larger pores than NF and is highlyeffective in removing pathogens, including par-asites such as giardia, but does not removesalts. Because it has large pores, UF does notleave a saline concentrate, although filters mustbe backwashed to keep the pores open. It isused primarily in the food and pharmaceuticalindustries, rather than large scale water treat-ment plants.

• MF has the largest pores of the membranesystems and removes particles, but not patho-gens or organics. MF may be used as a pretreat-ment process for RO or NF, thus reducingsome of the problems of those systems.

Several methods can be combined in thetreatment process. Tucson Water initially choseozone plus chloramine to treat CAP water be-cause officials viewed this as the most effectivetreatment method with the least risk to humanhealth. The ozone performs the initial disinfec-tion while the chloramine provides the residualto control microbes throughout the distribu-tion system. Tucson Water chose not to usechlorine in the CAP water treatment plant be-cause of concerns about THMs. Tucson Waterand some private water companies such asMetro Water, however, use chlorine to disinfectgroundwater. THMs generally are not a con-cern with groundwater since little organic mat-ter is found in groundwater to combine withchlorine.

REDUCING CORROSIVITY

All types of water are corrosive to some de-gree. Under certain conditions, however, some

water sources are more corrosivethan others as was evident whenCAP water was introduced in Tuc-son. Several factors influence watercorrosivity. Table 6-4 lists these fac-tors and suggests ways of control.CAP water also has sulfate and chlo-ride ion concentrations four to fivetimes higher than groundwater.Some evidence exists that the pres-ence of these ions (in high concen-trations) may slow down theformation of carbonate deposits onthe water pipes, which impede cor-rosion. The composition of thepipes also is an important factor.Old iron and steel pipes are highlysusceptible to corrosion. The treat-ment processes described below in-crease the acidity of the water, which then mustbe adjusted to avoid corrosion.

Maintaining a stable pH about 8.2 to 8.5 isan important factor in controlling corrosivity.The pH of raw CAP water varies, but is gener-ally higher (more alkaline) than Tucsongroundwater. When CAP water went throughthe water treatment process, however, the pHwas lowered to a point even lower than mostTucson groundwater—from about 8 to about7.4. Unless the pH is again raised, the scaleforming a protective coating inside the pipes isstripped away, exposing bare metal to the cor-rosive water. When CAP water was releasedfrom the treatment plant, the pH was not read-justed, which was an important factor in cor-roding pipes. One study showed that the pHvaried between 7.0 and 8.4 over the period ofCAP water use. In July 1993, for example, the

pH was under 7.4 and in August it rose to al-most 8.4.

Tucson’s long reliance on groundwatercaused the inside of the pipes to be coated withcalcium carbonate, forming a protective layeron the inside of the pipe. CAP water enteringthe system wore away this coating in somepipes and exposed the underlying metal to cor-rosion. In severe cases the pipes broke, and inless severe cases rust from the pipes entered thewater, causing a reddish color.

Reducing corrosivity may be as simple asadjusting the pH and waiting for the water andpipes to reach a new balance, or it may be morecomplex. The three basic ways of dealing withcorrosivity are:

• Increase pH by adding sodium bicarbon-ate, sodium carbonate or sodium hydroxide.

• Promote scale formation by adding phos-phate inhibitors such as sodium


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Figure 6-4 Concern about the quality of water providedby utilities has caused many people to seek alternative

sources of drinking water. Photo: Barbara Tellman.


76

orthophosphate, polyphosphate, zincorthophosphate or silicates.

• Replace or re-line old pipes most subject tocorrosion. (Replacing old pipes must generallybe done as a maintenance measure.)

Each of these methods has advantages anddisadvantages, but most water chemists favoradjusting the pH.

The pH impacts the disinfection processbecause higher pH increases the amount ofchlorine or ozone needed but does not affectthe amounts of chloramines or chloride diox-ide needed. Increased pH also tends to formhigher levels of THMs, but lowers the forma-tion of other byproducts. The disinfection pro-cess, in turn, alters the pH. Ozonation, forexample, lowers the pH. Tucson Water addedzinc orthophosphate to the CAP water to re-duce the corrosion after damage had already be-gun. This strategy not only was unsuccessfulbut it actually may have contributed to theproblem by further lowering the pH, prevent-ing the water and pipes from achieving a newbalance. Switching to copper, plastic or asbestoscement water mains would greatly help the situ-ation, but old steel or iron pipes in individualhomes might still be vulnerable to corrosion.Blending CAP water with groundwater hasbeen proposed as a solution and is generallysupported, but one study indicated that thismay actually increase corrosivity unless pH iscontrolled. According to this study blendingwould result in a favorable reduction of the sul-fate and chloride ion concentrations withoutsignificantly changing the beneficial alkalinity.As is shown in Table 6-5, however, many citiesdo blend Colorado River water without experi-encing major corrosivity problems.

REDUCING TOXICSUBSTANCES

Different toxic substances require differentkinds of treatment. Removal of TCE throughaeration is discussed above. Because neitherCAP water nor Tucson groundwater generallycontain problem amounts of other toxic sub-

stances, other treatment methods will not bediscussed.

REDUCING HARDNESSAND SALINITY

Ion exchange processes are used to reducehardness and also can be used to remove all


77

Figure 6-5 Out of the aborted effort to introduce CAP water to the community arose a brand ofCAP humor. Above is a “Fitz” cartoon that appeared in “The Arizona Daily Star” in the spring

of 1994. Used with permission from David Fitzsimmons, The Arizona Daily Star.


78

CITY SOURCE WATER

DISINFECTION METHOD

Chlorine Ozone Chloramine Membrane Other

Filtration

SALINITY

REDUCTION

CA

AnaheimAll Colorado River no yes yes no

hydrogenperoxide

no

Long Beach50 percent groundwater; 50 percentColorado River

yes no yes no no

Los AngelesChanging blend of ColoradoRiver, State Water Project, andgroundwater

yes no yes no no

San Diego10-20 percent local rainfall & statewater project; 80-90 percentColorado River

no

NV

Las Vegas (new)All Colorado River yes yes yes no no

AZ

BuckeyeAll polluted groundwater yes no yes no

35% waterloss; saltdisposal inirrigationdrainagecanals

electrodialysisdesalting

Glendale

(new)Salt River Project (SRP) water andCAP water

yes no no ultrafiltrationpilot plant 1mgd

no

Phoenix

Union HillsSRP water and CAP water yes no no no no

Tempe

2 plantsSRP water and CAP water yes no no no no no

Note: Of the above plants, only the Buckeye plant does not begin it water treatment with a basic filtration/flocculation process.

Table 6-5 How some southwestern communities treat their drinking water.


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The treatment strategies of three townsare described below to illustrate the impor-tance of analyzing community circumstancesand needs when choosing a suitable treat-ment method.

Buckeye, ArizonaBecause of a long history of irrigated agri-

culture, the town of Buckeye’s water supplywas too salty to drink, having TDS (total dis-solved solids) ranging from 1,500 to 4,000ppm. The water ruined pipes and appliancesand “just plain tastes bad.” In 1962, thetown became the first community in theUnited States to treat all its municipal watersupply with an electrodialysis desalting plant,with a capacity of 65,000 gallons per day(gpd). In 1988, the town constructed a new900,000 gpd electrodialysis reversal system inplace of the old system. The brine from theplant is put into evaporation ponds. Whenthe water evaporates, a saline sludge remainswhich is released to irrigation canals.

Glendale, ArizonaThe rapidly growing City of Glendale

needed to build another treatment plant totreat Salt River Project water and CAP water.Officials had four concerns:

• Land scarcity necessitated that the newwater treatment plant take up as little spaceas possible;

• Turbidity needed to be reduced by re-moving particles in the water, which at timesis clear and at other times murky, especiallyin the rainy season;

• Water had to be disinfected to meet an-ticipated new EPA standards for THMs;

• Taste and odor problems occurring occa-sionally due to algae growth in the canal hadto be confronted.

Glendale officials decided to useultrafiltration, a method to remove patho-gens, particles and 20 to 30 percent of the or-ganic matter that is a precursor of THMs.Since salinity was not a concern,nanofiltration or reverse osmosis were notconsidered. A pilot plant producing one mil-lion gallons a day will open this spring. Ifthe process works well, a much larger plantwill be built. The water is pretreated withchlorine, treated with alum and allowed tosettle so large particles drop out. The waterwill again be dosed with chlorine, then putthrough membrane filters and finally dosedonce more with chlorine in the distributionsystem. The use of powdered activated car-bon helps to reduce occasional taste andodor problems. Glendale does not treat waterfor corrosivity. Construction and operatingcosts are acceptable to the city, especiallysince the cost of ultrafilters has been decreas-ing as this method becomes more popular,and filters last seven years or more. This typeof filtration requires a smaller facility than

most other methods, so land use needs wereminimized.

Las Vegas, NevadaLas Vegas gets 85 percent of its water from

the Colorado River at Lake Mead and 15 per-cent from groundwater. The Las Vegas ValleyWater District considers Colorado River waterto be very high quality water needing littletreatment. The treatment process in use todayinvolves disinfection with chlorine, aeration,flocculation, filtration and more chlorinetreatment to produce a residual effect in thesystem. Although the water readily meets EPAstandards for THMs, a new treatment plantunder construction will use ozone disinfectioninstead of chlorine to minimize the THMcontent and meet anticipated new EPA stan-dards. Las Vegas’ Alfred Merritt Smith Plantwill be retrofitted with five 4,000pound-per-day ozone generators, and the newRiver Mountain facility will use three 2,000pound- per-day ozone generators. A smallamount of zinc orthophosphate is added atthe end of the process to retard corrosion andchloramine is added for residual disinfectionin the pipes. Ozonation will be implementedin the year 2000 at the existing Alfred MerrittSmith Treatment Facility and at the new RiverMountain Treatment Facility which will beconstructed by 2002. This is the same treat-ment method used at Tucson Water’sHayden-Udall Treatment Plant.

OTHER COMMUNITIES CHOOSE TREATMENT STRATEGIES

types of ions, such as arsenic, chromium, excessfluoride, nitrates, radium and uranium. Differ-ent ion exchange systems are available, fromthose useful at the commercial level to smallin-home systems. Sodium or potassium is usedas the exchange agent in water softeners.

Salinity can be reduced through thermalsystems (distillation) or through membraneprocesses. Thermal processes have been usedsince 4 B.C. when Greek sailors used an evapo-rative process to desalinate seawater. The ther-mal systems use heat to produce water vaporthat is condensed to produce fresh water. Ap-proximately 60 percent of the desalting systemsused in the world today are thermal systems.Only between 25 percent and 50 percent of thesource water is recovered, with the rest left in ahighly saline brine. These systems are most use-ful along the coast where a water supply is nota problem, and the brine can easily be returnedto the ocean.

Membrane processes include electrodialysis(ED), reverse osmosis (RO) and nanofiltration(NF). ED uses electricity to move salts selec-tively through a membrane, leaving fresh waterbehind. Because most dissolved salts are ionic(either positively or negatively charged) and theions are attracted to electrodes with the oppo-site charge, membranes that allow selective pas-sage of either positive or negative ions canaccomplish the desalting. The advantage of thistype of system in water-short areas is that 80 to90 percent of the water is recovered and only10 to 20 percent is lost to the brine.

RO and NF systems physically force waterthrough membranes. Larger suspended solidsmust be removed to avoid clogging the mem-branes. The primary difference between RO

and NF is in the size of the pores and the en-ergy needed for pressuring the water. Thesmaller the pores, the more energy is needed.

In any desalting process, a saline concen-trate is produced which must be disposed of insome manner. Various options have been sug-gested for CAP water. These include a pipelineto move the brine concentrate to the Gulf ofMexico, the Salton Sea in California or theColorado River at Yuma. Another option is toevaporate the brine locally, leaving a solid saltwhich could be disposed of in landfills. An-other possible option would be to join withother Arizona cities to build a desalting plantnear the Colorado River. The concentrate couldthen be more readily taken to the ocean orSalton Sea. Since Phoenix is not interested inparticipating in building such a desalting plant,this may not be a feasible option. If Tucsonadopts desalting as a treatment method, thecommunity would have to accept water lossesof between 15 and 25 percent as part of theprocess. If 130,000 acre-feet of water were desali-nated, between 25,000 and 40,000 acre-feetcould be lost as brine.

IMPROVING TASTE, ODORAND APPEARANCE

If taste, odor or appearance problems stilloccur after one or more of the treatment meth-ods described above, other solutions are avail-able that treat the problem of taste or odor atthe source. If the process itself is a source, suchas chlorine odor, the problem can be solvedthrough modifying the process or aerating thewater. If the source is an event like an occa-

sional algae bloom, the use of activated char-coal may solve the problem. Researchers at Ari-zona State University are currently researchingways to control taste and odor problems.

BlendingOne way to mitigate some water quality

problems is to blend water containing unac-ceptable levels of some contaminant with waterthat has little or none of the same contami-nant. For example, hard water can be blendedwith softer water to produce water somewherein between. Water that contains an unhealthylevel of a toxic such as TCE can be blended tolower the TCE level below the danger point.Blending, however, is not always as simple as itmay appear. Most studies have shown thatblending would improve CAP water quality.Tucson Water’s latest proposal is for a blend ofapproximately 45 percent CAP water with 55percent groundwater.

Soil (Alluvium)-Aquifer TreatmentSome utilities percolate wastewater or river

water through the soil for at least part of thewater treatment process. The water is thenpumped back up for use. Several pilot projectsin the Tucson area have been conducted, andresearch is continuing into the ability of soiland underlying materials to remove contami-nants. (The use of the term “soil” is not en-tirely appropriate because the soil often isscraped off to construct the basins, but sincesoil is the common term, it is used here.)

Experiments show that soil-aquifer treat-ment (SAT) removes almost all pathogens,more than 90 percent of organic matter, more


80

than 80 percent of total halogen, and none ofthe volatile organic compounds such as TCE ordissolved minerals or salts. In other words, SATcan be used for disinfection but must subse-quently be treated with chlorine or another dis-infectant to ensure safety and to retain residualdisinfection in the distribution system. The sizeand to some degree the composition of the al-luvium particles determines such factors as rateof percolation, clogging of the pores by algaeand bacterial growth. Clogging can be reducedby alternating wet and dry cycles. This providestime for any algae to die before the water isagain applied. Some soils are more porous thanothers, and the rate of percolation may changeover time as pores fill with water. Some pollut-ants, such as those that are found at landfills,may appear in the water. While some utilitiesuse SAT to treat wastewater, no major utilitiesuse the method to treat water for drinking pur-poses.

QUALITY OF CAP WATER

CAP water is generally of high quality. Itcontains no problem levels of toxic materials,and the low levels of microbes are easilytreated. The water comes from the Lake Havasusection of the Colorado River. Colorado Riverwater of similar quality is served to more than25,000,000 people in southern California, Ne-vada and Arizona. In Arizona and SouthernCalifornia the water may be blended with waterfrom other sources or used without blending.Some examples of how other communities useColorado River water are given below.

An important difference between CAP wa-ter and Tucson groundwater is the corrosivity

of the water. CAP water is more corrosive thanTucson groundwater partially because it con-tains higher levels of sulfate and chloride. Fromtheir experience with CAP water someTucsonans fully realize that corrosive water canseriously damage pipes and fixtures. As de-scribed above, corrosivity depends on pH, TDS,temperature and dissolved oxygen as well as thecomposition of the pipes.

Another major difference is the level of sa-linitY. (This refers to dissolved minerals, gener-ally not table salt.) Salinity of the groundwatervaries greatly according to location, with aver-age salinity in the Avra Valley about 210 mg/land levels up to 2,500 mg/l detected in ground-water near Green Valley and the mines. As isshown in Figure 6-6, the salinity of water deliv-ered to Tucson Water customers also varieswidely. Different sets of wells serve differentparts of the distribution system, causing salin-ity of water delivered to the customer to rangefrom below 200 mg/l to above 650 mg/l. Ingeneral, as pumping continues and water levelsdecline, the salinity of pumped water is ex-pected to increase.

The salinity level of CAP water varies sea-sonally and from year to year depending onflow conditions on the Colorado River. Higherthan average flows generally dilute salinity. In1995, the average annual salinity of ColoradoRiver water below Parker Dam, when adjustedto average flow conditions, was 775 mg/l – ormore than double the average of Tucsongroundwater. The TDS of CAP water deliveredto Tucson varies also, depending on a numberof factors. (Total dissolved solids is approxi-mately the same as salinity.)

As is indicated in Figure 6-7, ColoradoRiver salinity comes from both natural pro-cesses and human activities. Natural processesaccount for much of the salinity, as the riverand its tributaries pick up minerals from cer-tain kinds of rocks and soils. Highly salinesprings also raise the salinity levels. Irrigationcontributes salinity by consumptively using wa-ter, concentrating the salinity of the water leftbehind and by returning water to the river withadditional dissolved minerals from soils highin mineral content. Reservoir and canal evapo-ration, including the evaporation that occurs aswater is delivered via the open CAP canal, in-creases salinity concentrations because as waterevaporates, less water is left to dilute the sameamount of salts.

The salinity of the Colorado River starts atabout 50 mg/l in its mountain headwaters andincreases to over 800 mg/l at the Mexican bor-der. Salinity levels have been steadily increasingthroughout the lower basin and Mexico asmore river water is used and water evaporatesfrom the reservoirs. As a result salinity levelshave become a serious concern. Federal andstate programs have been enacted to removesalt loading sources on the river and preventfurther increases in TDS. These programs haveremoved thus far approximately 140,000 tonsof annual salt load on the river. ContinuedCongressional funding of these programs, how-ever, is in question. If salinity control programsare cut back or eliminated, TDS levels in the fu-ture are projected to exceed 900 mg/l at theCAP diversion point on the river.


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Salinity ConcernsAlthough the EPA does not consider TDS

to be a health issue, TDS is of concern for sev-eral reasons. Some level of TDS is desirable indrinking water and gives it a pleasant taste, butas levels increase beyond 500 mg/l many peo-ple complain of the taste. For this reason, EPAhas set a secondary (voluntary) drinking waterstandard for TDS of 500 mg/l.

Experience in Tucson and other communi-ties show that as TDS increases, people take ac-tion to avoid unpleasant effects. They may buybottled water, water softeners or home treat-ment systems, such as charcoal filters or reverseosmosis systems to improve water taste.

Saline water supplies can corrode andshorten the useful lives of water-using appli-ances such as water heaters, water faucets, dish-washers, clothes washers, evaporative coolers,

garbage disposals and toilet flush mechanisms.The useful lives of these appliances and fixturesshorten as TDS levels increase.

High salinity also can cause deteriorationof water pipes over time. Damage can resultfrom increased corrosion of metals that comein contact with the water and from scaling ofcontacted surfaces. Pipe damage resulting fromsalinity occurs mostly in steel or iron pipes.Damage can occur both in water mains and indomestic piping. Analysis of corroded pipesamples and interviews with Tucson Water staffafter the introduction of CAP water in Tucsonindicated that the most troublesome pipe waspoor quality galvanized steel pipe that lost itsprotective zinc coating. This left the steel un-derneath subject to corrosion. Galvanized steel,copper and plastic (PVC or polybutylene) pipemake up a large majority of the pipe used inTucson households. Approximately 25 percentof pipe used in Tucson area homes is estimatedto be galvanized steel. Tucson water mains aremostly asbestos cement and galvanized iron.Out of 2,400 miles of Tucson water mains, 220miles were galvanized steel or other steel in1994. By 1998-99, approximately 140 miles hadbeen replaced.

High salinity levels also can reduce cropyields and affect the growth rates of some land-scape plants. Soil salinity is controlled by waterquality and irrigation practices. For example,water TDS levels between 450 and 2,000 mg/lare considered slightly to moderately saline.Salt tolerance of vegetation varies greatly. Thenative mesquite, saltbush and some non-nativeeucalyptus have very high salt tolerance, whilethe native palo verde and jojoba and thenon-native pomegranate and lantana have only

Figure 6-6 TDS of water delivered to Tucson Water customers.

Sources: Tucson Water, Water Resources Research Center.


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moderate salt tolerance. Citrus has low salt tol-erance, but bermuda and rye grasses toleratesalts well.

Soluble salts can be removed from plantroots by adding excess water (leaching). CAPwater has about 2.5 more TDS than Tucsongroundwater, but most of the CAP salinity co-mes from salts that are benign to plants in thesoil-plant environment. Dissolved gypsum andcalcium carbonates, found in CAP water, arealso common minerals in the semi-desert soils.These minerals quickly precipitate (form asolid) and go out of solution in the soil envi-ronment and do not raise the salinity of thesoil significantly. Compared to groundwater,salt leaching estimates indicate that five toseven percent additional water may be neededto maintain the same salinity in soils whenCAP water is used to water plants.

WATERTREATMENTCOST

Costs BeforeTreatment

Your water bill reflectsthe various costs of pump-ing and delivering water,repayment of bonds to laypipes and build reservoirs,disinfection, reading me-ters and sending waterbills, conservation educa-tion programs and admin-istration. Further, TucsonWater adds a CAP sur-charge to cover the costs

of bringing in CAP. When it sells water bonds,Tucson Water repays the principal and interestthrough water rates, not through taxes or thegeneral fund. Other water providers also collectthe cost of building their water systemsthrough the water rates. The bill may also showa sewer charge Pima County.

Treatment CostsWater treatment is currently a very small

part of the water bill, but could become a sig-nificant part depending on CAP water treat-ment choice. Providing specific costs oftreatment methods is difficult because emerg-ing technology continues to lower the theircosts. For example, the cost of membrane fil-ters is about half what it was just a few yearsago. Some generalizations, however, are valid.

Adding chlorine is the least expensive treatmentmethod and adds almost nothing to the cost ofproduction, while desalting is the most expen-sive, especially when the costs of disposing ofthe brine are included.

Tucson Water spent more than $85 milliondollars to build the existing Hayden-Udall Wa-ter Treatment Plant in Avra Valley. Customersare still paying for the plant in their water bills.If we are to use CAP water, the least costly treat-ment alternative probably would be to upgradethat facility using the existingozone-chloramine system plus proper corrosiontreatment. Adopting a very different method —e.g., building a new facility or changing the ex-isting facility over to a new system — would bemore expensive. Voters probably would have toapprove additional bonds for any new facility.

Water treatment operating costs include thecost of chemicals, energy, salaries, and repairand maintenance. Chloramines and chlorineuse almost no energy, and the cost of the chem-icals is low. Ozone is energy intensive, since theozone is produced on site. Membrane filtrationis even more energy intensive since the processuses energy to force water through the mem-brane. The smaller the pore size, the more en-ergy is required to operate the system.Membranes also must be cleaned out periodi-cally since the pores become clogged, althoughsome systems have a self-cleaning technique,which itself uses energy. Membranes must be re-placed as they lose their effectiveness.

If desalting is the preferred choice, the costsof disposing of the brine can be high. For de-salting systems on sea coasts, this is not a prob-lem. The brine is usually dumped in the ocean,which is a convenient and inexpensive solution

Figure 6-7 Sources of salinity in Colorado River water(measured at Lake Mead).

Source: U.S. Department of the Interior, Quality of Water - Colorado River Basin, 1997.

to the problem. For land-locked places such asTucson, however, no easy solution exists. Thebrine can be evaporated and the solid matterlandfilled or it can be piped elsewhere as brine.In either case, between 15 and 35 percent of thewater is lost, increasing water costs. Shippingthe brine elsewhere would involve building apipeline almost as long as the CAP canal itselfto the Gulf of California or the ColoradoRiver. While a federal subsidy is possible, it isnot likely. If the salts are landfilled, either anew landfill for that purpose must be built orexisting landfills would soon fill up.

New landfills then would beneeded sooner than previously ex-pected – a cost to taxpayers, not towater rate payers. Landfilling in es-tablished landfills is not currentlyconsidered as an option for variousreasons including landfill space andproblems of the dried salts becom-ing airborne.

Although providing specifictreatment costs is not possible, vot-ers and elected officials need esti-mates of cost for variousalternatives before choosing a watertreatment method. One studyfound the costs of NF and RO are10 times higher than the costs ofozone- chloramine treatment, even

without considering the costs of brine disposal.According to this study the use of membranescould raise the typical residential water bill by$100 per year or more above the cost ofozone-chloramines.

Decision makers should also compare thecosts of not desalinating with the costs of desa-linating; e.g. what will it cost consumers to re-place water fixtures or appliances thataccumulate scale or corrode? What will con-sumers have to pay to leach salts from land-scapes or to buy home treatment systems orbottled water?

ISSUES TO CONSIDER

If CAP water is to be part of the total Tuc-son water picture, Tucson decision makers needto determine how to deal with the water qualityproblems listed above. Some of the issues theyneed to confront are:

• Whether to use CAP water directly in thenear future or to recharge it and use it later. Ineither case some form of treatment will beneeded, since recharge does not reduce salinityor provide adequate levels of disinfection;

• Which method to use to disinfect CAP wa-ter to ensure it is safe and meets EPA primarystandards;

• Which method to use to reduce corrosivityto minimize deterioration of pipes and fixtures;

• Whether or not to reduce salinity and, ifsalinity is to be reduced, what method shouldbe used and how the brine is to be disposed of;and

• Determine if taste and odor of CAP waterare problems and, if so, how to deal with thoseproblems.

While decisions about specific treatmentmethods may be highly technical and best leftto professionals, local residents need to expressopinions about the levels of treatment they pre-fer and what they are willing to pay for CAPwater.


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TREATMENT METHODANNUAL COSTS(cents/1000 gallons)

Chlorine-Chloramines 0.4

Increased Coagulant Dose 5.2

Ozone-Chloramines 9.8

Granulated Activated Carbon(a type of filtration)

18.0 - 28.0

Membranes/NF RO(not including disposal costs)

92.0

Table 6-6 Estimated operating costs of some treatmentmethods, not including construction costs.

Source: McGuire, et al., Disinfectants for Drinking Water Treatment - A White

Paper, 1995.

THE ROLES OF CITIZENS

Over the years citizen groups and individu-als have played important roles in settingwater policy. People have served on advi-

sory committees such as the City of Tucson’sCitizen’s Water Advisory Committee, PimaCounty’s Wastewater Advisory Committee andthe Arizona Department of Water Resources’(ADWR) Groundwater Users’ Advisory Com-mittee for the Tucson Active Management Area(TAMA).

Many non-profit groups have worked hardto support or change policies concerning waterover the years. Tucsonans for a Clean Environ-ment worked for cleanup of the TCE problem.In the 1970s, citizen groups such as Arizonansfor Water Without Waste, Citizens Against the

CAP and Citizens to Revise Arizona Water Lawunsuccessfully opposed CAP, and specificallyits use in Tucson. These groups, however,played a role in developing alternative strate-gies, including support of the 1980 Groundwa-ter Management Act. The Southern ArizonaWater Resources Association, on the otherhand, was initially established to ensure thatTucson got its fair share of CAP water andeventually developed a much broader purpose,including providing information to the com-munity on a wide range of topics. The TucsonRegional Water Council is another groupwhich supports the CAP but has a broader pur-pose of working to ensure a long-term watersupply for the area.

The importance of the “initiative process”in policy making was demonstrated in the 1995

city election when The Pure Water Coalitionsucceeded in reversing Tucson’s policies onCAP water use by persuading voters to approveProposition 200 and pass the Water ConsumerProtection Act (WCPA). The Citizens Alliancefor Water Security is following this same tradi-tion in promoting another initiative for the1999 ballot, which would extend the WCPA.These groups are opposed to direct use of CAPwater in the municipal water system, but pro-mote its use for alternate purposes..

Many other citizen groups such as theLeague of Women Voters, the Sierra Club, theArizona Native Plant Society and others havebeen involved in a variety of water issues, fromhazardous waste disposal to promotion oflow-water use plants in landscaping.

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Chapter 7

ROLES OF

CITIZENS AND

GOVERNMENT IN

WATER POLICY

The route water takes from its source, whether that be

an aquifer or the Colorado River, to its eventual

flow from a faucet is a complicated journey. Much

more is involved in that journey than the canals and

pipes that physically convey water from source to

destination. Government rules and regulations also have

a powerful influence on water flow, and their workings

may seem as complicated as any plumbing system, with

various levels of government involved in many different

water quality and water use issues. This chapter briefly

summarizes the major laws and institutions that control

and govern water. Some water management issues also

are examined, including whether some type of basin-wide

water management agency is needed; whether Tucson

Water customers who live outside city limits should be

allowed to participate in water decisions affecting them;

and whether water service should be privatized.

THE ROLES OF GOVERNMENT

Over the past century, various laws and reg-ulations at the federal, state and local levelshave impacted how we manage water. In addi-tion, interstate and even international treatieslimit the amount of Colorado River water wecan take. Finally, various Supreme Court deci-sions and legal settlements, especially those hav-ing to do with Indian water rights, affect ouruse of water. This chapter describes the mostsignificant laws, regulations and court decisionsthat affect water decisions in the Tucson area.The annotated bibliography lists sources formore detailed information.

Managing Tucson’s WaterNo single entity oversees or ad-

ministers all water use in the Tucsonarea. A combination of municipalwater utilities, private water compa-nies, irrigation districts, school dis-tricts, businesses and evenindividuals provide water in the area.There are 19 water companies withmore than 2,000 customers and morethan 130 other small water providers.(See Appendix B for a list.) Somewater utilities operate within Tucsoncity limits, and Tucson Water oper-ates both inside and outside city lim-its. All utilities provide water tocustomers under rules established bystate and federal governments to pro-tect the users and, in some cases,to protect future generations ofusers. Some laws and regulations

protect people from unsafe drinking water,while others are designed to prolong the wa-ter supply. Individuals who pump their ownwater for domestic use are not subject tomost of the rules — domestic wells thatpump less than 35 gallons per minute are ex-empted. Those relying on such wells, how-ever, are not protected by regulations toensure the health and safety of water con-sumers. Indian tribes generally are not sub-ject to state or federal rules, but often havetheir own system for managing water andprotecting users.

ADWR has authority over some aspectsof groundwater pumping within an area des-ignated as the Tucson Active Management

Area (TAMA). This includes most of the PimaCounty portion of the Santa Cruz River water-shed. (See Preface, Figure 4, which is a map ofTAMA.) ADWR performs overall groundwatersupply planning for the area. The agency alsoapproves or denies well drilling permits for allwells except small domestic wells and sets con-servation requirements for water providers.ADWR cannot, however, regulate pumping toprotect riparian areas nor can the agency coor-dinate the activities of various users or agencieswith water responsibilities. (More informationabout ADWR’s powers and responsibilities isprovided later in this chapter.)

The Arizona Department of Environmen-tal Quality (ADEQ) and the U.S. Environ-mental Protection Agency (EPA), are concernedwith the quality of groundwater and surface wa-ter. Their mandate is to prevent pollution of


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Figure 7-1 The federal government is an importantplayer in determining water policy, especially in water

quality matters. Photo: U.S. Library of Congress.

Figure 7-2 The Arizona Legislature hasauthority in various water management areas.Photo: Arizona Department of Library, Archives

and Public Records.

Chapter 7. Role of Citizens and Government in Water Policy

87

FEDERAL STATE COUNTY-CITY OTHER

Safe Drinking Water Act EPA ADEQWater providers may setstricter standards for theircompanies

Clean Water Act EPA ADEQ

Septic Tank Rules ADEQ County Health Department

Landfills EPA ADEQCounty and City eachoperate landfills

Pollution, Surface Water EPA ADEQ

Pollution, Groundwater EPA ADEQ

Areawide Water QualityPlanning

PAG

Hazardous Materials EPA ADEQ PCDEQ

Septic Tanks ADEQ PCDH

Groundwater Allocation ADWR

Surface Water AllocationBureau of Reclamation forColorado River Water

ADWR

Water Rates and RateStructures

ACC regulates privatecompanies and co-ops, butnot cities, or irrigation orimprovement districts

Tucson, Oro Valley, Maranafor their system

Boards for water companies,co-ops and districts

Floodplain andStormwater Management

EPA and FEMA ADEQ County and City FCDs

Agencies designated in bold below have the primary responsibility. Others have secondary responsibility and/or implement rules of the primaryagency. EPA - U.S. Environmental Protection Agency; ADEQ - Arizona Department of Environmental Quality; ADWR - Arizona Department ofWater Resources; ACC - Arizona Corporation Commission; FCD - Flood Control District; PCDEQ - Pima County Department of EnvironmentalQuality; PAG - Pima Association of Governments.

Table 7-1 Agencies responsible for water management in Pima County.

water supplies to ensure that consumers get safedrinking water.

The Arizona Corporation Commission(ACC) regulates rates charged by private watercompanies, but not by irrigation districts ormunicipal utilities. Its role of protecting thewater consumer sometimes conflicts withADWR’s role of requiring water conservationor the use of renewable supplies instead ofgroundwater. For example, ADWR might re-quire that a utility adopt water-saving strategies.To adopt such strategies, a water providermight need to raise water rates to cover thecost. The ACC, however, has rarely allowed theincreased rates. ACC has even prevented rateincreases to build treatment facilities to im-prove water quality. A rate increase is only al-lowed after a facility is actually in place.

WATER QUALITYREGULATIONS

Tucsonans have experienced occasional wa-ter quality problems over the past 100 years. Aflowing Santa Cruz River once was used as awater supply, and its quality at times was im-paired by cattle and human waste. Shallowwells tended to produce alkali-tainted water.Outhouses contaminated the shallow watertable.

Tucson was not unique. Throughout theUnited States in the nineteenth century wa-ter-borne diseases such as cholera, diarrhea, dys-entery or typhoid were prevalent. Measureswere taken to control water quality problemsand laws passed to require that water providersadopt such measures. For example, chlorine

was found to be a highly effective disinfectantby the late 1800s, and most major municipalsupplies were chlorinated by 1920. A dramaticdrop in water-borne diseases in the UnitedStates resulted. By the 1950s, however, peoplebegan to be concerned about human-made pol-lutants, especially toxic substances such asDDT. Developing technologies to deal withchemical pollutants took longer than workingout solutions to health problems relating tobacteria and viruses. The problem was morecomplex, with thousands of different pollut-ants. Recently, concern has focused on parasitesfound in water supplies, such ascryptosporidium and giardia. These havecaused widespread sickness, even death in sev-eral cities and are difficult to control by tradi-tional methods.

Various legislative efforts were made to im-prove water quality. Congress passed the CleanWater Act in 1972 to protect surface watersfrom pollution. The law initially listed only asmall number of pollutants, but more wereadded to the list as the law was applied overtime. The act attempts to maintain water qual-ity by controlling the kinds of wastes that arereleased to surface waters. In 1974, Congresspassed the Safe Drinking Water Act to assurethat drinking water supplies were safe. In 1980,Congress passed the Comprehensive Environ-mental Response, Compensation and LiabilityAct (CERCLA), more commonly known as theSuperfund Act. This law is designed primarilyto clean up areas that were polluted in the pastand to prevent the occurrence of future con-tamination from hazardous materials. In 1980,the Arizona Legislature passed the Environmen-tal Quality Act which, among other intents and

purposes, protects the quality of groundwater.Other significant laws that protect water qualityregulate hazardous materials and disposal ofwastes. Most of these laws are discussed later inthis chapter. Table 7-1 briefly shows whichagencies are responsible for various water man-agement matters.

Surface Water QualityFederal and state laws and regulations, un-

der the umbrella of the federal Clean WaterAct, regulate surface water quality. The stateand EPA administer portions of the federalprogram. States have the right to set their ownwater quality standards using EPA guidelines.These standards are to be reviewed every threeyears. EPA then issues permits and, if needed,takes enforcement actions based on the stan-dards. EPA, however, also issues National Pol-lution Elimination Discharge System (NPDES)Permits.

Point SourcesPoint sources of pollution are those

sources that come from a discreet location suchas a pipe. Point source discharge standards andpermits are based on the adoption of the bestavailable pollution reduction technology. Pointsources are much easier to regulate thannon-point sources — pollutants that come froma wide area, with no discreet discharge point. Alocal example of a point source is the outflowpipe from the Ina Road Water Pollution Con-trol Facility.

The law requires that the level of waterquality necessary to protect existing designateduses be maintained and protected. No degrada-


88

tion of existing water quality is permitted in anavigable water if the existing water qualitydoes not meet applicable water quality stan-dards. Where existing water quality in a naviga-ble water meets or exceeds applicable waterquality standards, the existing water qualitymust be maintained and protected. A proce-dure exists, however, for the ADEQ director toallow limited degradation in some cases.

NPDES permit conditions and water qual-ity standards are ultimately based on criteriadeveloped by EPA. These criteria are supposedto accurately reflect the latest scientific knowl-edge regarding such matters as the effects ofpollutants on the health and welfare of humansand wildlife; the effects of pollutants on biolog-

ical communities; andbiodiversity for varyingtypes of receiving waters.

An important pur-pose of regulation is toprotect designated uses.An established use is noteasily changed to a lessprotective use. Such achange can be made,however, through the“use attainability analy-sis” process in which theapplicant must provethat the existing pro-tected use does not actu-ally exist in the stream.

Non-point SourcesNon-point source

pollution is pollution that comes from severaldiffuse sources, not through a specific dis-charge — e.g., grazing. It is usually regulatedthrough Best Management Practices (BMPs),which are guidelines developed through consul-tation between ADEQ and the affected indus-try. BMPs are intended to achieve a specificwater quality goal, rather than mandating spe-cific prescribed conditions. For example, Ari-zona has BMPs for grazing. The business orindustry then is required to meet perfor-mance-based standards.

NPDES Permits.One section of the law sets requirements

on industries and local governments to abatepollution. The EPA issues NPDES permits to

entities that discharge to “waters of the UnitedStates.” (This is defined very broadly.) Permitconditions are set according to federal require-ments, but with specific requirements oftenbased on local conditions. The permits are fora specified period of time, but are renewable.Sometimes the conditions are changed whenthe permit is renewed. An example of an entitywith a NPDES permit in Pima County is PimaCounty Wastewater Management Department.

Stormwater PermitsStormwater runoff from urban areas is a

major non-point source of pollution in water-courses. Arizona, with its dry washes andmonths without rain, experiences special prob-lems with runoff. Pollutants such as oils settleon roads, and the infrequent rains allow pollut-ants to accumulate. During summer storms,many streets fill with water that rapidly drainsto washes and ultimately to rivers, carryinglarge amounts of pollutants that have collectedon the streets. The daily news often containswarnings to drive carefully during the first ma-jor summer rain because of oil slicks on thestreets. Also insecticides, cleaning fluids andother domestic pollutants might be present instormwater, as well as industrial pollutants, al-though these are more carefully controlled thandomestic pollutants.

Pollution from urban stormwater runoff isvery difficult to control since it comes fromthousands of sources and enters washes andrivers in many different ways. As awareness ofstormwater quality problems increased, Con-gress directed EPA to develop regulations re-quiring large cities to establish programs to


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Figure 7-3 The origins of point source pollution are distinct andidentifiable; hence a point source also is called an end-of-the-pipe

source. Photo Barbara Tellman.

control urban runoff. EPA regulations consid-ered urban population figures to determinewhich cities needed a NPDES permit. BothTucson and Pima County fit the criteria forneeding a permit. The county submitted atwo-part permit application, with the first partsubmitted in 1991 and the second part in 1993.The city filed a storm water permit applicationwith EPA in 1992 and in 1998. Both city andcounty permits were approved.

To obtain a NPDES permit, an applicantmust address various EPA concerns. Measuresmust be taken to control such activities as il-licit connections and illegal dumping to stormdrains and to control runoff of pollutantsfrom municipal landfills, industrial facilitiesand construction sites. The applicant also mustinventory land uses to determine the quantityand quality of discharged water and develop amanagement plan for stormwater runoff. Thisplan involves identifying problem areas andworking out strategies and practices to reducethe flow of pollutants into bodies of water. Aspart of the plan, the applicant must describewhat already has been done to eliminate pollut-ants from stormwater runoff as well as whatnew efforts will be undertaken to further con-trol such pollutants.

Pima County’s permit requirements in-clude street sweeping, land development con-trols, a household hazardous waste programand a stormwater sampling program. Thecounty also advises businesses and constructionpersonnel about stormwater regulations.

The City of Tucson has an ongoing Storm-water Master Plan (TSMP) incorporated into itsNPDES permit. The TSMP emphasizes thepreservation of naturally vegetated watercourses

to improve water quality and urges residents toharvest rainwater. Retaining stormwater onproperty reduces runoff flowing over streetsand paved surfaces and picking up various pol-lutants. Other aspects of the permit includeconducting site inspections of private develop-ments on five acres or more.Also, the city will inspect indus-trial sites that are required to ob-tain NPDES permits, to ensurethey are in compliance. The cityalso monitors stormwater qualityproblems in the community toanticipate and prevent problemsbefore they occur. The city also isemphasizing public education oroutreach, to make people awarethey have a personal effect onstormwater quality.

TREATMENT PLANTFUNDING

Another section of the CleanWater Act provides financial as-sistance for constructing munici-pal wastewater treatment plants. The law hasbeen more successful in controlling biologicalpollutants than in dealing with toxic materials.During the 1980s, Congress provided fundingthrough EPA to build wastewater treatment sys-tems. Most of Arizona’s large treatment plantswere built at least partially with federal subsi-dies which helped pay the costs of growth. Inthe 1990s, these funding sources dried up asCongress cut back on federal spending. Theprogram changed to a “revolving fund” which

provides seed money for loans to communitiesfor wastewater treatment. The loan paymentsare in turn made available to other communi-ties as loans to continue support for buildingtheir wastewater treatment facilities.

GROUNDWATER QUALITYLAWS

Arizona’s Environmental Quality Act is de-signed to prevent groundwater pollution. Notfederally mandated, the act is entirely an Ari-zona initiative, passed in response to seriousgroundwater pollution problems. The act calledfor the creation of ADEQ, to manage waterand air quality and solid waste regulation.


90

Figure 7-4 Rainfall flowing over urban surfaces picksup various constituents and forms urban runoff

nonpoint source pollution.

The heart of the water quality section ofthe law is a requirement that anyone who planswater discharges that might reach groundwatermust go through the Aquifer Protection Permit(APP) process. This applies to discharges di-rectly to watercourses as well as discharges ondry land overlying a groundwater source. Theapplicant must show that the discharge will notcause or contribute to a violation of AquiferWater Quality Standards as defined by regula-tion. All aquifers are considered to be drinkingwater aquifers with drinking water standards,unless reclassified for a lesser quality. An aqui-fer that does not meet drinking water standardsfor some constituents, but meets the standardsfor others may have a different level of stan-dard for each constituent. The standard is notnecessarily determined at the point of dis-charge, but may be determined at a point un-derground and is influenced by existing waterquality. If a standard for that groundwater hasalready been exceeded, the applicant must dem-onstrate that no further degradation will occur.

Applicants must use Best Available Demon-strated Control Technology (BADCT) to ob-tain a permit. Certain dischargers, such asagricultural dischargers, which fit into a groupsharing common characteristics, do not have togo through the full process. Instead they maybe treated as part of the “General Permit” pro-cess that already has established rules. Exemp-tions to the APP requirements includehouseholds, stock ponds, mining overburdenreturned to the excavation site, water transpor-tation systems, community sewer systems,storm water impoundments, water storage facil-ities and water used for public landscaping(e.g., golf courses).

The law also has a permitting system for re-charge and underground storage facilities.ADWR reviews such facilities for water supplyconcerns and ADEQ reviews the water qualitymatters. The applicant must meet all APP regu-lations except BADCT requirements.

Wastewater reuse projects also go through apermitting process. Regulations are stricterwhen treated wastewater is to be used in areasaccessible to the general public (e.g., schoolyards) than when used in areas that are fenced,with restricted public access (e.g., an industrialsite). Edible crop irrigation with effluent is themost strictly regulated.

HAZARDOUS WASTES

EPA has requirements for undergroundstorage tanks, with special emphasis on gasolinetanks. The agency also has a wellhead protec-tion program for discharges in the vicinity ofwater wells. EPA also regulates hazardous wastesources and landfills and maintains theSuperfund or CERCLA, which is designed toclean up hazardous waste sites. The polluterthen may be charged for the cleanup. Far moresites have been identified nationally than havebeen cleaned up under this program. Arizonahas 111 official Superfund sites, with few hav-ing been cleansed of hazardous materials. A cu-rious feature of the Superfund program is thatit exempts oil-based hazardous wastes. Ari-zona’s WQARF (Water Quality Assurance Re-volving Fund) helps pay for clean up ofpolluted sites that do not meet the Superfunddefinition. Lack of funding has plagued theprogram.

Wastewater and Septic SystemsIf wastewater is released to a surface water

source, a NPDES permit is required. ADEQ re-quires a permit if wastewater is reused, re-charged or released into a constructed wetland.County health departments, under ADEQ over-sight, administer septic tank permits understate legislative rules.

SAFE DRINKINGWATER ACT

The federal Safe Drinking Water Act regu-lates the quality of water provided to consum-ers by water companies and municipalities.Under this act, EPA regulates public water sys-tems, defined as those that pipe water to at least25 people or 15 connections for at least 60 daysper year. These systems may be owned byhomeowner associations (e.g., Winterhaven), in-vestor-owned water companies (e.g., Green Val-ley Water Company), cities and towns (e.g.,Tucson Water), domestic water improvementdistricts (e.g., Metro Water), irrigation districtsserving domestic customers (e.g., Flowing WellsIrrigation District) and others (e.g., The Univer-sity of Arizona).

The act does not cover smaller services orindividual domestic wells. EPA sets basic stan-dards for pollutants of concern and requireswater providers to take certain measures tomeet those standards. EPA is supposed to iden-tify the potential pollutants in drinking water,study their possible health effects and set stan-dards for the problem pollutants. The listgrows as new problems are detected. New regu-lations adopted in 1998, for example, require


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water providers to control cryptosporidium, awater-borne parasite that poses a public healththreat. The law requires testing at regular inter-vals and consumer notification if standards arenot met. Although numerous violations havebeen recorded in recent years in the Tucsonarea, almost all those violations were for techni-cal errors, such as failure to report or monitor.Almost no cases were reported of water qualitystandards being exceeded.

EPA recognizes that small water providers,unlike large utilities, often are unable to afford

certain types of testing and treatment proce-dures. Variances therefore are allowed based onfinancial condition and the number of custom-ers served. Smaller companies, however, muststill use the best available technology within acertain price range. In addition, funding isavailable to assist those small companies withthe greatest needs. Drinking Water RevolvingFunds were created in each state to channel fed-eral money to small water providers. EPA setsrequirements for states to follow to maintain el-igibility under this program

WATER SUPPLY REGULATIONS

Our present system of water law grew outof the intense competition for water amongearly American miners and settlers. People atthat time were competing for surface water, andthe laws that developed were intended to pro-tect the rights of those who arrived first fromthe claims of those who arrived later. The lawto determine surface water rights is called theprior appropriation doctrine. By the early1880s, most of the surface water in the Tucsonarea was claimed for use.

Competition for groundwater developedmuch later when increasingly powerful pumpsenabled pumpers to draw water from beneathlands owned by others. Groundwater laws werepassed in the 1950s to protect existing farmersfrom being pumped dry by new farms. Thelaws, however, hardly take note of the fact thatsome groundwater and surface water are actu-ally hydrologically connected. Pumping that af-fects surface water rights is therefore legalthroughout most areas of the state because

under Arizona law, surface water and ground-water are generally considered to be separate.

As more people moved to Arizona, the bur-geoning urban areas competed with agriculturefor groundwater. In 1980, the Legislaturepassed the Groundwater Management Act(GMA) which sets goals and policies for themost problem-plagued parts of the state.ADWR, which was established to administerthe GMA, is responsible for allocation of bothsurface water and groundwater.

GROUNDWATERMANAGEMENT ACT

Central to the GMA was the establishmentof four Active Management Areas (AMAs) inareas of the state with the greatest groundwateroverdraft problems: the Phoenix, Prescott, Pinaland Tucson AMAs. A fifth, the Santa CruzAMA, was created in 1994 when it was split offfrom TAMA. Some other areas were designatedIrrigation Nonexpansion Areas (INAs). (SeeFigure 7-5.) In these areas, new pumping for ag-riculture is limited, but other pumping is not.Most of eastern Pima County is includedwithin TAMA. There are no INAs within PimaCounty.

Each AMA must develop five successiveplans for reaching its goal over the period 1980to 2025. The first four plans each cover aten-year period, while the last plan covers the fi-nal five years. The AMAs are currently prepar-ing to enter the third management period,which covers the years 2000 to 2010. TAMA is-sued its draft Third Management Plan in thefall of 1998.


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Figure 7-5 Arizona’s Active ManagementAreas and Irrigation Non-Expansion Areas.

Safe YieldThe management goal designated for all

AMAs except the Pinal AMA is that of reach-ing “safe yield” by the year 2025. Achieving safeyield involves reaching, and thereafter main-taining a long-term balance between the annualamount of groundwater withdrawn and the an-nual amount of natural and artificial rechargewithin an AMA. Each AMA has its own criteriafor satisfying the requirements. For example,the Phoenix AMA allows 7.5 percent of the an-nual supply to be mined groundwater. InTAMA, as much as 15 percent can be minedgroundwater. The balance must come from re-newable supplies — CAP or other surface water.Therefore, even the GMA safe yield require-ments allow depletion of groundwater, but overa long period of time. In the Draft Third Man-agement Plan for TAMA, ADWR states that

even with use of CAP water and conservationmeasures, the safe yield goal will not be met.

The ADWR water budget is calculated byestimating water use based on projected popu-lation, probable per capita water use, agricul-tural and industrial use and Indian use.Supply is based on assumptions about CAPuse, recharge and effluent use. Estimating upto 45 years into the future is obviously diffi-cult, and projections are revised in succeedingmanagement plans. For example, populationestimates for TAMA in the year 2025 havebeen revised downward, from 1,693,000 peo-ple in the Second Management Plan (SMP) to1,266,500 in the Third Management Plan(TMP). These figures represent official stateprojections.

Assured Water SupplyNew subdivisions are required to demon-

strate that they have an “assured water supply”before being built. What counted as an “as-sured water supply” originally was very broadand included groundwater withdrawals thatwould lower the water table by as much as1,000 feet. An assured water supply also couldbe demonstrated by contracting for CAP wateror subcontracting with an entity that had con-tracts for CAP water, whether the CAP waterever reached the subdivision or not. Assuredwater supply rules have been revised and some-what tightened to include the following crite-ria:

• Sufficient quantity of water is continuouslyavailable to satisfy the water demands of the de-velopment for 100 years;

• Water source meets water quality standards;

• Proposed use of water is consistent withconservation standards;

• Proposed use is consistent with water man-agement goals; and

• Applicant is financially capable of install-ing the necessary water distribution and treat-ment facilities.

The concept of assured water supply doesnot assure sustainability for more than 100years, and the requirements can be met in someways that do not assure sustainability. Partici-pating in a recharge program or contracting forCAP water can be sufficient to meet the re-quirement.

Municipal Conservation ProgramsAMAs establish conservation goals for each

municipal water provider or major agriculturalor industrial water user. Large municipal waterproviders are allowed to choose among fourprograms to regulate their water use. The totalgallons per capita per day (gpcd) program is thebase program, under which gpcd goals are setfor each provider. If goals are not met, a pro-vider can be fined, although provisions allowwater use in very dry years to be balanced withuse in wet years. Alternative approachesinclude:

• Non-Per Capita Conservation Program,which allows water providers having resourcesto implement conservation programs as well asaccess to alternative supplies, to implement spe-cific indoor and outdoor water conservationmeasures as well as education programs insteadof meeting specific gpcd goals. To be acceptedinto this program, providers must demonstratethat they have reduced groundwater use.


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“PAPER” OR “WET” WATER?

“Paper water” is a term coined to dis-tinguish between actual usable water(“wet water”) and water that exists onlyas a calculated figure to satisfy certain re-quirements. A water budget, for example,may include assumptions about howmuch water will be recharged in a largearea, without considering whether thewater is in fact available for recharge or,if recharged, whether it can be recoveredin an area where it is needed. The bud-geted water therefore is a calculated fig-ure and represents “paper water.”


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Third Management Plan Scenario: Projected Future Conditions Assuming Third Management Plan Conservation Goalsare Achieved by 2010 and Continue through 2025, Tucson Active Management Area

SECTOR 1990 1995 2000 2005 2010 2015 2020 2025Projected AMA Population 655,000 768,000 838,300 921,000 1,005,300 1,092,200 1,179,200 1,266,500Projected Irrigation Acres 40,000 36,100 35,320 35,750 33,900 30,400 26,400 21,400MUNICIPAL SECTORTotal Demand 130,100 155,500 171,900 186,300 199,800 216,200 230,000 243,100Total Supply 130,100 155,500 171,900 186,300 212,100 232,000 249,800 267,100

CAP 0 l00 8,500 l07,000 108,100 119,500 131,700 143,800Effluent 6,300 7,700 11,600 23,400 32,900 36,000 37,100 37,700Groundwater 123,800 147,700 151,800 55,900 58,800 60,700 61,200 61,600

AGRICULTURAL SECTORTotal Demand 93,800 98,000 104,700 117,700 107,500 97,000 85,000 70,000Total Supply 93,800 98,000 104,700 117,700 107,500 97,000 85,000 70,000

CAP 0 0 0 10,400 15,800 15,800 15,800 15,800Effluent 4,000 1,800 3,000 3,000 3,000 3,000 3,000 3,000Groundwater 89,800 96,200 101,700 104,300 88,700 78,200 66,200 51,200

INDUSTRIAL SECTORTotal Demand 48,800 60,200 71,000 72,100 73,300 73,000 74,200 75,400Total Supply 48,800 60,200 71,000 72,100 73,300 73,000 74,200 75,400

CAP 0 0 0 0 0 0 0 0Effluent 800 800 1,300 1,700 2,900 3,600 4,200 4,700Groundwater 48,000 59,400 69,700 70,400 70,400 69,400 70,000 70,700

Evapotranspiration 3,700 3,700 3,700 3,700 3,700 3,700 3,700 3,700Total Demand 276,400 317,400 351,300 379,800 384,300 389,900 392,900 392,200Total Groundwater use 265,300 307,000 326,900 234,300 221,600 212,000 201,100 187,200(Less) Net natural recharge 60,800 60,800 60,800 60,800 60,800 60,800 60,800 60,800(Less) Incidental recharge 70,300 82,300 80,800 39,600 35,000 34,400 33,600 32,300(Less) Cuts to aquifer 0 0 5,100 32,900 35,800 37,700 41,400 45,100(Less) Extinguished credits 0 0 11,700 8,400 7,900 7,600 0 0Actual Overdraft 134,200 163,900 168,500 92,600 82,100 71,500 65,300 49,000(Less) Remediation water 0 0 8,400 7,000 6,500 6,500 6,500 6,500(Less) Allowable groundwater 0 0 10,000 32,200 34,700 36,200 36,400 36,400Accounting Overdraft 134,200 163,900 150,100 53,400 40,900 28,800 22,400 6,100

NOTE: all units are acre-feet unless otherwise noted.

Table 7-2 The draft water budget for the Tucson AMA.

Source: Arizona Department of Water Resources, Draft Third Management Plan, Tucson AMA, 1998.

ADWR monitors the implementation and re-sults of these measures.

• Alternative Conservation Program, whichallows providers with an unusually large andgrowing amount of non-residential water use(e.g., a major new industrial plant) some flexi-bility in meeting conservation requirements.After limiting annual groundwater withdrawals,providers must meet gpcd requirements for res-idential users only, while implementing specificconservation measures for non-residential waterusers. ADWR monitors achievement of residen-tial water use goals and implementation and re-sults of non-residential conservation measures.

• Institutional Provider Program, which al-lows providers serving primarily non-residentialusers, including prisons, hospitals, military in-stallations, airparks, and schools, to meet con-servation requirements designed specifically fornon-residential use. These conservation require-ments usually include specific conservationmeasures for non-residential uses and a maxi-mum residential gpcd rate.

Small water providers, defined by ADWRas serving less than 250 acre-feet of water peryear, generally lack the resources to implementconservation programs, and are exempt frommeeting specific gpcd requirements. Small pro-viders are required to meet “reasonable conser-vation requirements,” as established by thedirector of ADWR.

ADWR has no authority to enforceconservation requirements directly on water us-ers or consumers, only on water providers. Thiscauses problems for some water companies.Regulated by the ACC, private water companieshave to assume the initial costs of conservationprograms since they are unable to charge their

customers for the cost of such programs untilthe program has been proven effective. Alsochanges in rate structures to encourage conser-vation have to go through a rate hearing pro-cess before the commission. The ACC does notregulate municipally-owned water companies,but such utilities including Tucson Water, OroValley Water and Metro Water go through theirown public process before changing water rates.

Agricultural ConservationRequirements

The GMA regulates agricultural water usein several ways. First, no new agricultural landcan be developed for irrigation within AMAsand INAs. Only lands which were legally irri-gated with groundwater in the five years priorto implementation of the GMA in 1980 maycontinue to be irrigated with groundwater.Such lands received an IrrigationGrandfathered Right. Only holders of the rightmay withdraw, receive and use groundwater forgrowing crops on two or more acres of landwithin an AMA.

Second, farms are given a maximum an-nual allotment of groundwater to be used forirrigation. The allotment is calculated by multi-plying the maximum number of acres irrigatedat any time from 1975 through 1979 by an irri-gation water duty. The irrigation water duty iscalculated from the annual amount of waterper acre that is reasonable to apply to producethe crops that were historically grown from1975 through 1979. This irrigation water dutyis reduced over time as increasing water appli-cation efficiencies are required.

In order to allow for variations in weatherand changing agricultural market conditions,farms are given a flexibility account, allowingthem to accumulate credits for the differencebetween their actual water use and the ground-water allowance, or borrow from the account iftheir actual groundwater use exceeds their al-lowance. Accumulated credits can be used infuture years, if needed, to meet conservation re-quirements. There is no limit to the number offlexibility credits that can be accumulated, andfarms are allowed to borrow up to 50 percentof their maximum annual groundwater allot-ment. Annual groundwater allotments were setnear the historic peak of irrigated acreage; thusmuch more groundwater than is needed is le-gally available to farmers each year. With irriga-tion efficiencies increasing on farms andsignificant amounts of farmland out of produc-tion, many farms have accumulated large flexi-bility account balances.

Industrial Water UseAWDR assigns conservation requirements

specific to each category of industrial water useand encourages substitution of renewable watersources for groundwater.

• Turf-Related Facilities are given annualwater allotments calculated for each facility.Water for golf courses is generally limited to23.8 acre-feet per hole, or enough water for 5acres of turf per hole at 4.6 acre feet per acre.

• Metal Mines must limit water loss fromtailings ponds, recycle water, and reduce wateruse for dust control.

• Power Plants must achieve a specifiednumber of “cycles of concentration” when they


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are in full operation. Cycles of concentra-tion is a measure of the degree to whichcooling water is recycled. As water is recy-cled, salt concentrations increase due toevaporation, and fresh water must beadded. Maximizing cycles of concentra-tion saves water.

• Large-Scale Cooling Facilities mustreach specific concentrations of silica ortotal hardness in the water used for cool-ing before the water is discharged and newwater is used.

• Sand and Gravel Operations mustrecycle wash water and implement two ad-ditional conservation measures related todust control and cleanup activities.

• Dairies are given annual water allot-ments based on assumed water needs.Dairies can alternatively apply to the direc-tor of ADWR to be regulated under theBest Management Practices ConservationProgram, under which a combination of suchpractices will be required.

INDIAN WATER RIGHTS

In general, federal environmental laws donot apply to tribal lands. Most tribes have theirown environmental and/or wildlife agencies,with regulations often modeled on federal laws.Since tribes control some headwaters of Ari-zona rivers, actions on tribal lands may signifi-cantly affect nontribal areas. Conversely,actions on nontribal lands have affected Indianlands. In some cases, nontribal entities such asmines have been allowed to use tribal landswith fewer environmental restrictions thanwould apply on nontribal land. Tribes and the

U.S. Bureau of Indian Affairs have becomemore cautious in recent years about agreementsthat might result in polluted, waters and havemore vigorously enforced their laws.

The settlement of Indian water rights is anissue with broad implications throughout Ari-zona, not only to the tribes involved but alsoto non-Indians. Throughout much of U.S. his-tory, Indians, their water rights systematicallyignored and violated, have been an aggrievedparty. The basis for Indian water rights claimsis a U.S. Supreme Court decision (the WintersDecision), which established the principle thatwhen the federal government set aside lands forIndian reservations or to serve other federalpurposes, the government also implicitly re-served sufficient water rights to accomplish the

purposes for which the reservations werecreated. These unrecorded and unquantifiedIndian water rights therefore were establishedat the time reservations were created, and sogenerally predate Anglo, non-Indian waterrights. Although the Winters Decision wasdecided in 1908, only recently have Indianwater rights gained serious recognition in thecourts.

Settling Indian water rights is very im-portant to Arizona. With 21 Indian tribescontrolling about 28 percent of the state’sland base, tribal water claims are extensive.Some observers argue that total tribal waterrights in the state could exceed Arizona’s to-tal surface water supplies. With no newsources of water available to allocate to tribes,water to settle Indian claims could comefrom present water users. The senior prioritydates of Indian water rights means suchrights have precedent over later water claims,

usually belonging to non-Indians. Some CAPwater, however, is presently unallocated and isavailable for use in Indian water rights settle-ments.

The state of Arizona presently is involvedin adjudications of the Gila River and LittleColorado River watersheds to determine thetypes, amounts, and priority dates of the rightsof all water users in the watersheds. First initi-ated in 1978, the two Arizona adjudicationswill eventually determine the water rights ofmost water users in the state, including Indiantribes and the federal government. Seven tribeshave filed claims in the Gila watershed, theprincipal watershed in Arizona incorporatingthe state’s largest population centers, Tucsonand Phoenix. The Gila River adjudication is es-


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Figure 7-6 Tohono O’odham ollas, or clay water jars,from the nineteenth century are reminders of Native

Americans’ early water rights. Photo: ArizonaHistorical Society/Tucson.

timated to be the largest lawsuit ever filed inthe United States, affecting 60,000 parties, in-cluding many in Pima County.

Tohono O’odham Water RightsAlthough representatives of state, federal

and tribal governments usually negotiate In-dian water rights, implications of settlementscan greatly affect cities and counties. For exam-ple, an understanding of the Tohono O’odham(Papago) water claims is essential when consid-ering Tucson’s water future.

Tucson’s early growth and development de-pended upon groundwater found in the UpperSanta Cruz Basin. This aquifer extends beneaththe San Xavier District of the TohonoO’odham. As early as 1881, the Tucson WaterCompany drilled wells east of San Xavier to ob-tain water. This wellfield developed with thegrowth of the city, and by the 1970s Tucsonpumped approximately 40,000 acre-feet of wa-ter annually from wells located just outside thereservation. Having by law to rely on an unre-sponsive federal government to promote andprotect its interests, the tribe was left at a dis-tinct disadvantage.

By 1976, after several court cases that sup-ported and defined Indian water rights, theTohono O’odham were in a position to claimmost of the available water in the Tucson Ba-sin. The implications to non-Indian interests ofsuch a claim were vast, with the possibility thatbond ratings would be jeopardized, privateloans more difficult to obtain, economicgrowth halted, and water possibly reallocatedfrom current users to the Tohono O’odham.

In 1975, the federal government, on behalfof the Tohono O’odham, sued the City of Tuc-son, mining companies and agricultural inter-ests. In brief, the suit claimed the defendantsdamaged the tribe’s water rights by excessivepumping. The tribe had at least two strategiesto follow: negotiate a settlement or precedewith the suit to its final resolution. In the faceof the cost, time and various uncertainties asso-ciated with a court case, a consensus developedthat a negotiated settlement would be in thebest interest of all involved.

Tucson took the suit very seriously as is in-dicated by an excerpt from an Arizona DailyStar editorial at the time: “More than a centuryof government failure to preserve the Papagos’interests assured the tribe a court victory. Andvictory for the Papagos could have meant thepermanent shutdown of mines and farms andan end to city growth and development.” Suchdire consequences, however, were unlikely, evenwith the Indians winning a court case.

Negotiations took place with the expressgoal “to develop a fair and reasonable water re-sources plan which will satisfy the present andfuture water needs of eastern Pima County,” in-cluding “a speedy resolution of Papago Indianwater right claims.” In making the best of athreatening situation, non-Indians used the suitas part of a strategy to benefit their own inter-ests. By claiming that Colorado River waterwould be needed to negotiate with the TohonoO’odham, non-Indians were building a case forthe federal government to complete the CAPcanal to Tucson. Whatever settlement was nego-tiated would need to be financed by federal leg-islative appropriation.

Southern Arizona Water Rights Settle-ment Act On October 12, 1982, after agree-ment was reached by both House and Senate,President Reagan signed into law the SouthernArizona Water Rights Settlement Act(SAWRSA). The act obligated the U.S. Secretaryof Interior to deliver 66,000 acre-feet per yearto the San Xavier and Schuk Toak districts ofthe Tohono O’odham Nation. This total is toinclude 37,800 acre-feet of CAP water and28,200 acre-feet of wastewater effluent or ex-change water, which may be used to exchangefor another type of water suitable for agricul-ture. The tribe has the right to market its nego-tiated water to users within TAMA or parts ofthe Upper Santa Cruz Basin not within TAMA.Costs associated with the delivery of CAP waterunder the sale, exchanges or temporary disposi-tions are non-reimbursable. The act also estab-lished a cooperative fund to pay operations,maintenance and repair charges related todelivery.

A schedule was set for delivering water anddeveloping facilities for its use. Meanwhile adispute arose among the Tohono O’odham Na-tion, its San Xavier District, and allottees, indi-vidual land owners on the San Xavier District.The dispute was the result of developing oppo-sition to dismissing the U.S. v. Tucson lawsuitand to the terms of the SAWRSA settlement.The dispute spawned two additional lawsuits:Alvarez v. Tucson and Adams v. U.S.

Since about 1990, efforts have been madeto negotiate an agreement between the allottees,the nation, the federal government and the ma-jor defendants to implement SAWRSA and dis-miss the lawsuits. Negotiations are ongoing.


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Meanwhile work which was to be done bythe U.S. Bureau of Reclamation to develop thefacilities for delivering and using the water onthe reservation has been delayed, although con-struction began in spring of 1999 on a pipelineto take water to the San Xavier District for agri-cultural purposes. The non-Indian defendants,however, have been more timely in meeting

SAWRSA obligations. Tuc-son and Pima County havecontributed effluent, withfunding appropriated bythe state and non-Indian in-terests to set up a trustfund. Until U.S. v. Tucsonis dismissed, however,SAWRSA is not fully effec-tive. As of yet, no water hasbeen delivered to the In-dian people.

CAP AND THECOLORADORIVER

Arizona’s allocation ofColorado River water is de-termined by the Law of theRiver, a collection of legis-lation, compacts, judicialdecisions, internationaltreaties and administrativerules that governs water al-location on the river. TheColorado River Compactof 1922 divided the riverinto two basins: the Upper

and Lower Basins, with the river’s average an-nual flow divided equally between the basins.Lees Ferry in northern Arizona marks theboundary between the two basins (See Figure7-7). According to the compact each basin is toreceive 7.5 million acre-feet per year. Arizona isa member of the Lower Basin, along with Ne-vada and California. A division of the waters of

the Lower Basin originally was suggested byCongress in the Boulder Canyon Project Actand upheld in the Arizona vs. California Su-preme Court decree in 1964. Arizona was allot-ted 2.8 million acre-feet of Colorado Riverwater, California was allotted 4.4 millionacre-feet, and 300,000 acre-feet was allocated toNevada. Along with its Lower Basin allocation,Arizona also gets 50,000 acre-feet of Upper Ba-sin water.

Approximately 1.3 million acre-feet of Ari-zona’s allocation of Colorado River water isconsumed along the mainstem of the river,mainly for agricultural purposes. This leavesan average of 1.5 million acre-feet per year tobe carried to central Arizona via the CAP canal.The canal has a design capacity for delivery of2.1 million acre-feet per year, which is reducedto approximately 1.9 million acre-feet per yeardue to the need for routine maintenance. Thisextra capacity allows Arizona to take waterabove its annual allocation if a surplus is de-clared on the river.

CAP deliveries may be interrupted bydrought shortages on the river or by the needto repair and maintain the canal. To gain thesupport of California’s delegation for Congres-sional approval of the CAP, Arizona was forcedto agree that, in times of shortage, California’sfull 4.4 million acre-feet will be delivered beforeany water will be provided to the CAP. As a re-sult, any shortages in the Lower Basin will beborne first by the CAP. The risk of droughtshortage is projected to increase over time. Af-ter the year 2025, the probability of shortagesaffecting CAP water users is anticipated toreach approximately 30 percent. The probabil-


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Figure 7-7 The Colorado River Basin.

ity that municipal and industrial users will beaffected is approximately 5 percent.

The law assigns the highest priorities fordelivery of subcontracted CAP water to Indianand municipal and industrial (M&I) subcon-tractors. The lowest priority is assigned tonon-Indian agriculture. This means if sched-uled deliveries must be curtailed in any year,deliveries to non-Indian agricultural subcon-tractors will be cut first.

The amount of water delivered over theyear is set, but the amount delivered each dayvaries greatly over the year, depending on de-mand. At times of high demand municipal us-ers get first priority, but only for directdelivery. Municipal recharge projects have alower priority than agriculture. In March 1997,delivery to recharge sites was halted temporarilyto meet demands for direct municipal use andagriculture. This reversal of the priority systemthat normally places agriculture last may re-quire recharge systems be designed to acceptlarger amounts of water at times when deliver-ies are high to compensate for the times whendeliveries are cut. Possible changes to this pol-icy are being discussed.

Concerns about CAP outages due todrought or maintenance point to the need forsome mechanism to enhance delivery reliabil-ity. This could be either storage at the end ofthe aqueduct (terminal storage) or an opera-tional plan that could involve keeping a certainnumber of groundwater pumps ready to pro-vide water in case of an emergency. Consider-ation of terminal storage has been delayedindefinitely as a result of Tucson’s decision tosuspend direct delivery of CAP water.

The draft Environmental Impact Statementrelating to terminal storage estimated that Tuc-son would experience planned maintenanceoutages of five to 30 days per year. Emergencyoutages are projected at zero to three times ev-ery 10 years. These emergency outages couldlast up to two months. An emergency outagelasting 48 to 365 days could happen zero totwo times every 50 years. Situated at the end ofthe canal, Tucson is in the position of havingthe least reliable CAP water supply. Terminalstorage options include a 15,000 acre-footabove-ground reservoir, a 15,000 acre-foot peryear underground storage and recovery facility,and installation of redundant features to mini-mize maintenance outages. Cost of theabove-ground reservoir was estimated to beabout $100 million. If built as part of the CAP,the costs would be borne by CAP water users inPima, Maricopa and Pinal counties, with fi-nancing by the federal government at a 3.342percent interest rate over a 50-year period.

CENTRAL ARIZONA WATERCONSERVATION DISTRICT

The Central Arizona Water ConservationDistrict (CAWCD) is a state agency with theprimary responsibility of managing the CAP.Voters in Maricopa, Pima and Pinal Countieselect board members generally based on popu-lation. The district is concerned with water feesand property taxes for CAP, water allocation,canal operation and maintenance. CAWCD isresponsible for repaying CAP reimbursableconstruction costs to the federal government.The district also works with the Arizona Water

Banking Authority and the Central ArizonaGroundwater Replenishment District to imple-ment CAP storage and recovery programs.

PROGRAMS TOPROMOTE RECHARGE

Underground Water Storage, Savings,and Replenishment Program

Administered by ADWR, the UndergroundWater Storage, Savings, and ReplenishmentProgram (UWS) encourages the use and/orstorage of renewable supplies, including CAPwater. There are two types of facilities allowedunder this program: Underground Storage Fa-cilities and Groundwater Savings Facilities.

Underground Storage Facilities (USFs) in-volve physical recharge of water through injec-tion wells, infiltration basins, or naturalwatercourses. Water stored at these facilities canbe designated for one of several uses: recoveryin the same calendar year (annual storage andrecovery), long-term recovery using storagecredits, or not to be recovered at all. If the wa-ter is recovered, it does not have to be recov-ered in the same place as it was stored.However, recovery rules are designed to preventrecovery of water in areas where groundwaterlevels are substantially declining.

Groundwater Savings Facilities (GSFs) usu-ally involve farms which agree to use CAP wa-ter rather than pumping groundwater. GSFs arereferred to as “in-lieu” recharge facilities be-cause CAP water is used in lieu of groundwater,but GSFs do not involve physical recharge. In atypical GSF arrangement, an entity such as amunicipal water provider sells CAP water to a


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farm, usually at a price lower than what thefarm would pay to pump groundwater. In re-turn, the state grants credits to municipal pro-viders for the amount of groundwater thatotherwise would have been used. The municipalprovider can use these credits to offset pump-ing of groundwater in meeting ADWR conser-vation rules. A majority of the activity underthe UWS program to date in TAMA has beenthrough GSFs.

Arizona Water Banking AuthorityArizona cannot currently directly use all its

allotted CAP water and does not expect todirectly use the full allotment until the year2030. Since California claims a right to takeunused Colorado River water, Arizona has de-vised a way of keeping as much of it as possiblein the state. The Arizona Legislature created theArizona Water Banking Authority (AWBA) toacquire unused portions of Arizona’s allocationof Colorado River water and put it to use forstorage underground or, in other words, to re-charge it in central Arizona. AWBA is autho-rized to store water to meet one of four overallgoals: to protect municipal uses from possibledrought situations or CAP delivery interrup-tions; to meet Indian water rights claims; tomeet local water management objectives; or tofacilitate interstate water banking with Califor-nia or Nevada. AWBA is funded using propertytaxes, groundwater withdrawal fees in countieswith CAP water (Maricopa, Pinal and Pimacounties) and money from the state’s generalfund.

AWBA does not construct recharge facili-ties, but uses recharge structures built by other

entities, such as Tucson Water or CAWCD.The water flows through the CAP canal to thestorage facility, and AWBA pays CAWCD forthe water costs. AWBA participating entitiesthen benefit by accruing credits for the waterstored and by using the water when needed un-der certain conditions dictated by state law.Credits earned with money from the generalfund are used to benefit cities, towns and waterproviders along the aqueduct. Water storagecredits earned with money from groundwaterwithdrawal fees are to be used in the AMAwhere the fees were collected. Credits from theproperty tax accrue to CAWCD to meet de-mands of municipal and industrial customerswhen CAP supplies are interrupted.

AWBA also is allowed to negotiate and en-ter into interstate water banking agreementswith California and Ne-vada, subject to approvalby the director of ADWRand subject to other condi-tions. Such agreementswould allow Californiaand/or Nevada to pay tostore unused ColoradoRiver water in Central Ari-zona. This obviously bene-fits Arizona as more wateris added to our aquifers,but the other two LowerBasin states also wouldgain from the transaction.In later years, those statescan “recover” their storedwater under a forbearanceagreement, through whichArizona would refrain

from taking a portion of its entitlement of Col-orado River water equal to the amount of waterto be recovered. The state that had banked thewater could then recover the banked water di-rectly from the river. In effect, by paying tostore unused Colorado River water in Arizona,California or Nevada can earn the right to laterdivert portions of Arizona’s Colorado River al-location from the river.

The AWBA directly recharged approxi-mately 45,000 acre-feet of excess CAP water in1997 and approximately 70,000 acre-feet in1998, of which about 12,000 acre-feet was inPima County at the Central Avra Valley Re-charge Project, the Avra Valley Recharge Projectand the Pima Mine Road Recharge Project. Thebank also accrued 149,000 in water storage


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Figure 7-8 Decorative fountains raise an issue beyond supplyand demand — the aesthetics of water.

Photo: UA Biomedical Communications.

credits for in-lieu “recharge,” none of whichoccurred in Pima County.

Central Arizona GroundwaterReplenishment District

In 1993, the Arizona Legislature passed alaw that provides an alternative method forsubdivisions and water providers to meet therules requiring a demonstrated 100-year supplyof water. Entities that couldn’t otherwise dem-onstrate an adequate physical supply can paythe Central Arizona Groundwater Replenish-ment District (CAGRD) a fee for the ground-water that the subdivision or water provider is“mining.” The CAGRD then takes responsibil-ity for acquiring and re-charging water to offsetthe mined groundwater.Since “replacement” wa-ter does not have to berecharged in the samelocation as the with-drawal, localizedgroundwater declinesmay not be preventedby the arrangement. Theoverall managementgoal of safe yield, how-ever, is furthered.

Under CAGRD thefees paid are the same(per unit volume) foreach of the contributing“members.” Membersthat are water providerspay the fee directly toCAGRD. In the case of

certain subdivisions, each lot owner is a mem-ber and the individual pays in the form of anassessment on the property tax bill. One of theconsequences of this is that the costs associatedwith an “assured” water supply are not bornedirectly by developers. This is one factor for thepopularity of the CAGRD option. To date, ap-proximately 115 subdivisions and eight waterproviders have applied for, or obtained, mem-bership in the CAGRD.

LAKES AND POOLS

In 1987, the Legislature enacted a law re-stricting the use of surface water or potablegroundwater in artificial lakes and ponds in

AMAs. A new lake cannot exceed 12,320 sq. ft.— the size of an Olympic-sized pool — unlessfilled with wastewater or poor quality ground-water. Lakes built before 1987 are exempted, asare lakes in public parks. The size of residentialswimming pools also is limited to Olympicsize, although the number of pools is notlimited.

WATER TRANSFERS

In the 1970s, Tucson Water began buyingfarmland in the Avra Valley to obtain waterrights in the area. Once the courts determinedthe arrangement was legal under certain condi-tions, Tucson considered Avra Valley ground-water an important part of its water supply. Inthe 1980s, other cities went even farther afieldin search of water, to rural areas remote fromurban centers. For example, Scottsdale boughtland along the Bill Williams River in westernArizona. Some people in rural areas becameconcerned about losing water supplies andproperty tax base critical for their survival. Inresponse, the Legislature passed a law limitingnew transfers of water from non-AMAs. Be-cause of the law, Tucson is not able to importwater from outside the TAMA, such as fromthe San Pedro River.

FEDERAL ENVIRONMENTALLAWS

Two federal laws that have some impact onwater decisions are described briefly below, al-though they are not primarily water-related.


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Figure 7-9 The Endangered Species Act is concerned with the effectsof human activity on the natural environment. Above is the federally

protected desert tortoise. Photo: Barbara Tellman.

National EnvironmentalProtection Act

The National Environmental ProtectionAct (NEPA) is intended to ensure that signifi-cant projects done by the federal governmentor that use any federal subsidies do not causeenvironmental damage in the process. Provi-

sions do not ap-ply to private,nongovernmentalprojects unlessthey have a fed-eral componentsuch as a housingdevelopment thatinvolves federalloan guarantees.

When an eli-gible project isplanned, an Envi-ronmental Assess-ment (EA) mustbe conducted. Ifthis assessmentdoes not indicatethat environmen-tal problems areanticipated, thepublic has theright to commentand either ap-prove or request amore detailed En-vironmental Im-pact Statement(EIS). Other fed-eral agencies such

as U.S. Fish and Wildlife Service must be giventhe opportunity to comment on matters undertheir jurisdiction. The public has the right tocomment on the EIS and a public hearing mustbe held. If troublesome issues arise, a mitiga-tion plan is developed.

Endangered Species ActThe purpose of the Endangered Species Act

(ESA), passed in 1973, is to conserve the na-tion’s biological heritage consisting of its ani-mal and plant species. The law enlists allfederal agencies and departments in an effort toconserve threatened and endangered speciesand to promote the purposes of the act. Asstated in Section 7 of the act, all federal agen-cies are “to insure that actions authorized,funded, or carried out by them do not jeopar-dize the continued existence” of an endangeredspecies or “result in the destruction or modifi-cation of habitat of such species.” Section 9 ofthe ESA includes prohibitions against “take”which is defined in the act as “harass, harm,pursue, hunt, shoot, wound, kill, trap, captureor collect or attempt to engage in any suchconduct.”

The ESA also charges the above agencies toidentify and designate “critical habitat” forlisted species, based upon the best scientificdata available. This is to identify and protecthabitat essential to the species’ survival and re-covery. Critical habitat is the specific areas,within or outside the species’ geographicalrange at the time of listing, which contain es-sential physical or biological features for con-serving the species and which may requirespecial management or protection.

When constructing the CAP canal in theTucson area special precautions were taken toavoid harming various species. An importantdeer movement area between the TucsonMountains and the Schuk Toak District of theTohono O’odham Nation west of Tucson iscrossed by the CAP canal. To minimize disrup-


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LARGEST MUNICIPAL SERVICE WATER USE TOTAL

PROVIDERS AREA POP. (Acre-feet) GPCD

City of Tucson 621,290 115,860 166

Metro Water District 44,153 9,161 185

Town of Oro Valley 23,416 6,503 248

Flowing Wells Irrig. District 15,000 2,945 175

Community Water Co. 14,261 2,249 141

Avra Water Co-op 6,688 935 125

Lago del Oro Water Company 6,461 1,787 247

Davis-Monthan AFB 6,191 1,969 284

University of Arizona 5,695 1,624 255

Ray Water company 4,617 658 127

Green Valley Water Company 4,390 2,318 471

AZ State Prison Complex 4,097 602 131

Hub Water Company 4,078 1,118 245

Arizona Water Company 3,984 366 82

Marana Municipal Water System 3,467 623 160

Las Quintas Serenas 2,388 345 129

Marana Water Service 1,736 337 173

Farmers Water Company 983 373 339

Forty-Niner Water Company 872 833 853

(1997 data. Figures may differ from Appendix B because they represent different years.)

Table 7-3 Largest municipal water providers serving Pima County.


tion to deer movement and other wildlife inthis unique area and to preserve this corridor,the U.S. Bureau of Reclamation buried parts ofthe canal under six major washes and pur-chased 4.25 square miles of deer habitat. Thecorridor will be managed by Pima County aspart of the Tucson Mountain Park system andwill be protected from future development.

This area also contains important habitatfor the kit fox, the endangered Tumamocglobe-berry plant, and three potential endan-gered species: the desert tortoise, the Gila mon-ster and the Thornber’s fishhook cactus. Thecorridor will protect about 27,000 Thornber’sfishhook cactus. Obviously any constructionprojects involving the movement and storage ofwater must proceed especially carefully to antic-ipate ESA concerns.

Even now, with the CAP system essentiallycompleted, the ESA continues to impact waterresource planning. Along with water, the CAPbrings fish and other aquatic species from theColorado River. Some aggressive, non-nativefish pose a potential threat to Arizona’s nativefish species, all of which are listed as endan-gered or threatened. The concern is that duringperiods of high precipitation or snowmelt,when normally dry rivers are flowing, the CAPcanal might provide a water link allowingnon-native fish to reach the headwaters ofstreams, invading the habitat of native species.Eliminating such hazards can require buildingexpensive fish barriers or other obstacles tonon-native fish, resulting in water project de-lays and additional costs.

REGULATION OF WATERCOMPANIES

The 19 largest municipal water providerswithin the Tucson area are listed in Figure 7-3.(See Appendix B for a list of all water providersin Pima County.) Tucson Water, the largest,serves about 80 percent of the total population.About 12 percent of the population is servedby private domestic wells and a large numberof very small companies.

Different regulations regarding water ratesapply to different types of water providers.Elected officials and the mandate of the elector-ate control municipal water companies. Thiscan lead to disenfranchisement when theboundaries of the water company and the mu-nicipality are different. Also voters within theTucson city limits who receive water from utili-ties such as Flowing Wells Irrigation Districthave the right to vote on Tucson Water issues.Both of these situations prevail in Tucson. Tuc-son Water’s service area extends far beyond citylimits, and private water providers operatewithin city limits. Municipal water companiescan approve increased rates, and they may floatbond issues, spreading capital costs into futureyears.

Private water companies and water coopera-tives, on the other hand, are regulated by theACC. Raising or restructuring rates requiresACC approval in a rate hearing. Private compa-nies generally are not allowed to raise rates torecover future costs. For example, if ADWR re-quires conservation programs, the ACC may re-fuse a rate increase to cover the costs until afterthe money has been spent and the programproven to be effective. Similarly, a small water

company cannot increase rates to build a newwell or a treatment system. Instead, it mustbuild the well or the treatment system, then re-cover the costs. Also ACC does not allow watercompanies to recover CAP holding costs. Theseare costs for CAP water rights not presently be-ing used.

As a result, private water companies andwater cooperatives may find themselves in aregulatory bind. ACC’s goal is to keep rates lowto benefit consumers; the ADWR goal is toconserve water within AMAs; and an ADEQgoal is to ensure safe drinking water quality. Aprivate water company confronting these variedregulatory goals may have problems initiatingconservation programs. Without the power toborrow money or float bonds, a small watercompany’s very survival may be threatenedwhen major capital improvements are needed.

The ACC does not regulate irrigation dis-tricts, regardless of whether they actually pro-vide irrigation water (e.g., Flowing Wells) orwater improvement districts (e.g., MetropolitanDomestic Water Improvement District). Thesedistricts are responsible solely to their boardsand members. ADWR regulates all water pro-viders regarding water supply (assured watersupply and safe yield) and water use issues (con-servation), with EPA and ADEQ regulating wa-ter quality issues.

REGIONAL WATER QUALITYPLANNING

The Pima Association of Governments(PAG) is responsible for coordinating waterquality and transportation planning as well as


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regional population projections. Each localgovernment entity, regardless of its size, hasone vote on PAG decisions. An EnvironmentalPlanning Advisory Committee and its WaterQuality Subcommittee, which is made up ofgovernment staff and local residents, study andmake recommendations on such matters as newwastewater treatment facilities, water reclama-tion and pollution cleanup. PAG votes on theirrecommendations to determine whether theybecome policy.

FLOODPLAIN MANAGEMENT

Both Pima County and the City of Tucsonare involved in flood control and the develop-ment and enforcement of floodplain ordi-nances. Pima County’s flood control district(FCD) is governed by the Board of Supervisorsacting in its capacity as Pima County FCDmanagers. Established by state statute in 1978,county flood control districts work to reducethe risk of flood loss, minimize the impact offloods on human safety, health and welfare,and restore and preserve the natural and benefi-cial values served by floodplains. Established aspolitical taxing subdivisions of the state, FCDshave the power to levy taxes to supportflood-control projects. Their area of jurisdic-tion may include incorporated and unincorpo-rated areas.

Legislation also allows an incorporated cityor town within a county to assume responsibil-ity for its floodplain management. Tucsonmaintains its own floodplain management pro-gram within Pima County. Pima County FCDis mainly concerned with areas outside city lim-its. Intergovernmental agreements (IGAs) have

been signed with the city, however, for the dis-trict also to be responsible for waterways withincertain incorporated areas. IGAs are likely to beworked out for regional watercourses that havesignificant flow during 100-year flood events,such as the Rillito Creek and the Santa CruzRiver. Pima County therefore maintains themajor watercourses in the area, although thecity may be responsible for sections of them.Finally, floodplain maps are under the jurisdic-tion of the Federal Emergency ManagementAgency (FEMA) which administers the nationalflood insurance program. Communities that donot comply with FEMA rules are not eligiblefor federal flood insurance.

POWERS OF COUNTIESAND CITIES

Counties generally have only those powersgranted to them by the state, unless they haveadopted charter government. Counties are re-quired to look after the “health, safety, and wel-fare” of their residents. As a result, theymaintain health departments, building codes,etc. Counties do not currently have the author-ity to operate water systems. Pima County has adepartment of environmental quality which isprimarily involved with air quality and hazard-ous waste. County health departments havesome water quality responsibilities related tohuman health; e.g., they regulate septic tanks.County zoning decisions may be based on theability of government to provide services suchas wastewater treatment. In at least one case amassive rezoning was denied on the basis of an

insufficient water supply, the lack of whichcould have been a serious health problem.

Cities have varied levels of involvement inwater management. Some cities (e.g., Tucson)operate water companies, and many cities oper-ate wastewater facilities (e.g., Show Low). Manycities have water conservation programs (e.g.,Phoenix).

Cities and counties may assess fees on newdevelopment (impact fees) to recover the costof providing services to the new area. Such ser-vices include water and wastewater facilities.Both cities and counties operate under stateand federal water quality and quantity laws.

City and County OrdinancesCities and counties also have their own

laws, referred to as ordinances. In general, theseordinances may be stricter than state or federalones, but may not be less strict. Thus a city can-not opt out of following the Safe Drinking Wa-ter Act, but it can decide to meet morestringent standards, such as the tighter THMstandard that the City of Tucson has imposedon itself. On occasion, however, the state gov-ernment has preempted this right.

Water Consumer Protection ActThe Water Consumer Protection Act

(WCPA), a ballot proposition passed by City ofTucson voters in 1995, (See page 139) had threemajor goals:

• prohibit Tucson Water from directly deliv-ering CAP water unless the salt content wassubstantially reduced;


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• prohibit delivery of water from pollutedsources, including treated TARP water (See page66) ; and

• compel the city to offset groundwater with-drawals with recharge, including recharge ofCAP water.

Other goals included:• encourage the city to trade and sell its CAP

allotment;• avoid recharge in areas of known landfills;

and• prevent disinfection byproducts such as

THMs from being introduced into the aquiferthrough treatment and direct injection re-charge. The WCPA did not deal specificallywith corrosivity.

In 1997, Proposition 201 was on the ballotbut failed to pass. It would have repealed manyof the provisions of the WCPA, substitutingless restrictive goals.

Tucson Xeriscape Ordinance

This ordinance applies to new multifamily,commercial and industrial developments. Itsgoal is to conserve water by applying xeriscapeprinciples. These principles include usingdrought-tolerant plants, maintaining limitedgrass areas and applying mulch and soil im-provements. Landscaped areas must be de-signed to take advantage of storm waterrun-off, and water-conserving irrigation systemsare required.

City and County Plumbing CodesBoth city and county require that wa-

ter-efficient fixtures be used in all new residen-

tial and commercial construction. Toilets mustbe ultra-low flush (i.e., 1.6 gallons per flush orless) and faucets must not exceed 2.5 gallonsper minute. The code also applies to replace-ment of old fixtures. Requirements also are es-tablished for evaporative coolers, airconditioners, decorative fountains and water-falls.

Water Waste OrdinanceSince 1984 it has been illegal for people

within the City of Tucson to let water flow offtheir property onto public areas or other prop-erty. A “water cop” can fine individuals, prop-erty managers and landscape contractors whoare guilty of this infraction. Tampering withwater meters also is illegal.

Golf Course Water UseTucson and Pima County have ordinances

requiring the use of CAP or effluent for newgolf courses where feasible. (See Chapter 5 formore information.)

Emergency Water ConservationUpon declaring a water emergency because

of problems with water supply, the Tucson CityCouncil may prohibit or restrict non-essentialuses of water. Examples of restricted activitiesare outdoor irrigation except areas using re-claimed water, washing of sidewalks, outdoorwater-based play, automatic water service in res-taurants, misting systems, filling swimmingpools and spas, and washing of vehicles exceptat facilities with recirculation systems. Excep-tions can be allowed for reasons of publichealth, safety or economic hardship.

MANAGING WATER ANDWASTEWATER

Tucson operates the largest water system inthe area, serving about 600,000 persons an aver-age of about 97 million gallons of water daily.The city serves customers both inside and out-side city limits. Since Tucson Water is man-aged by the Tucson City Council, people whoare not city residents have little say on city wa-ter decisions, even though they receive city wa-ter. Approximately 16 other water providersserve another 155,000 customers in the area.The remaining 81,000 water users are served byvery small water companies or have their ownwells. Some of these water companies arewithin the city limits of Tucson, Oro Valley orMarana. The cities do not regulate the activitiesof these water providers and cannot requiretheir compliance in such activities as water con-servation programs.

Water providers that are not municipal wa-ter departments, on the other hand, have littleor no say in certain city decisions that affectthem, such as rezonings and conservationordinances. ACC regulates rates and some pro-cedures of private water companies, but notmunicipal utilities or irrigation districts.ADWR can require all three types of water util-ities to implement conservation measures andmeet sustainability goals but has no jurisdic-tion over water users themselves. At times,ACC and ADWR rules conflict.

Pima County handles most wastewater inthe region, with treatment plants at RogerRoad and Ina Road, next to the Santa CruzRiver. Pima County also runs several smalltreatment plants outside the metropolitan area.


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Because of an intergovernmental agreement be-tween Tucson and Pima County, Tucson hasrights to most of the effluent that comes fromwastewater treatment facilities throughout PimaCounty. A few neighborhoods have their owntreatment facilities, and some people have sep-tic tanks or other kinds of individual treatmentsystems. Some subdivisions with golf courses,such as El Conquistador, use treated water

from their local community for watering thegolf course.

COORDINATING WATERMANAGEMENT

Despite, or perhaps because of the manylaws and rules, no one agency has legal author-ity to coordinate water use area-wide. This is tothe detriment of efficient water management.

TAMA and the Pima Association of Govern-ments (PAG), however, address some basin-wideissues that were previously discussed. The fol-lowing further characterizes water managementin the Tucson area:

• No agency has the authority to require wa-ter users to take a particular kind of water, suchas effluent or CAP water. Some people believemines and farms should use lower quality waterand leave the groundwater for drinking pur-poses. But the type of water that businesses andwater companies use is generally determined bythe market place or historical accident. In otherwords, they generally use the cheapest watersource, which often is groundwater. Also, indi-viduals have the right to pump groundwaterfor their own domestic use, and over 24,000private wells exist in the Tucson area. The onlylimiting factors are well spacing regulationsand the cost of drilling and operating a well.

• No agency can mandate that all categoriesof water users shall contribute to help pay forsolutions to water problems. For example, noagency can require businesses that use ground-water to pay a fee to support CAP activities inan effort to prevent the water table from declin-ing. While some local taxes and pumping feesare charged, the funds do not help pay TucsonWater’s cost of using CAP water.

• No agency can require individuals to con-serve water. ADWR can set per capita goals thatwater providers must meet, but those providersin turn have no authority to require water sav-ings of their customers. The City of Tucsoncould pass an ordinance limiting water use, butit would not apply to people living outside citylimits and probably not even to customers ofother water providers within city limits.


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Figure 7-10 Jurisdictional boundaries.

Sources: Pima County Technical Services, Arizona Department of Water Resources.

• Elected officials often make land use deci-sions without worrying about long-term watersupplies. Rezonings within established waterservice areas certified for assured supply mayproceed, although new developments outsidesuch areas must go through the approval pro-cess. In 1999, a rezoning for the Canoa Ranchnear Green Valley was denied partly because ofwater supply issues. This, however, was the ex-ception, and other reasons existed for opposi-tion to this rezoning.

BASIN-WIDE WATERMANAGEMENT

Local water management is characterizedby a complex web of overlapping, and occa-sionally conflicting political and geographicaljurisdictions. Overlapping jurisdictions in theTucson area are shown in Figure 7-10. Figure7-11 provides a generalized model of municipalwater policy management. Though attentiontends to be focused on elected officials, manyother “players” are involved. The public, partic-ularly the voting public, has the ultimate say inmost policy matters and has several avenues forinfluencing water policy (rules, laws and guide-lines) and water management (implementationof policy).

Coordinated and comprehensive ba-sin-wide management has been advocated atvarious times. Such “watershed management”has several obvious advantages, and a few moresubtle disadvantages. The most compelling rea-son cited for watershed management is the abil-ity to treat water resources as part of anintegrated system. In its most optimistic imple-mentation, decisions such as land use, transpor-tation and population growth all would beevaluated in terms of their basin-wide impacton water resources.

Critics of the existing situation note thedifficulty in establishing long-term plans whenso many of the critical decisions are splitamong different agencies and groups. Moreoverthe responsibility to meet long-term demands isoften unevenly distributed. For example, whiledevelopers are required to demonstrate a100-year assured water supply, they are not re-quired to consider the basin-wide impacts of

their development. This raises some thornyhydrologic issues as well as concerns about rela-tive inequity. In another example, some havecomplained that the costs of renewable supplieslike CAP water have been disproportionatelyborne by Tucson Water customers.

The expectation is that stronger basin-widemanagement would reduce disparities and pro-mote true sustainability. Promoters also notethat a watershed management authority couldreduce some of the political and economic inef-ficiencies inherent in the current situation.

The splintered nature of local water man-agement can be counted as both a cost and abenefit. The inefficiency that results from mul-tiple jurisdictions also can provide some mea-sure of control against a single entity havingtoo much authority. A watershed authoritycould make it easier to implement ecologicallysound policies, but it also could be an efficientmechanism for mischief.

Some people have argued that the Tucsonregion should have a government agency withpowers to buy and sell water throughout the re-gion and to determine who uses which kinds ofwater. There could still be private water compa-nies under the larger umbrella agency. The Tuc-son City Council vetoed establishing an agencywith some of these powers when it votedagainst establishing the Santa Cruz Valley Wa-ter District in 1993. This agency would havehad some of the responsibilities of the CentralArizona Groundwater Replenishment Districtfor this area.

Benefits of area-wide management includereserving the highest quality water for munici-pal use while lower quality water would be usedfor industry and agriculture. Also the costs of


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Figure 7-11 Generalized model of municipalwater policy.

augmenting the supply could be distributedmore fairly throughout the region. The manag-ers could either be elected directly by the votersor appointed by the county and cities in the re-gion. One argument against this approach isthat the managers would have enormouspower. If they were appointed, with one voteper city (like PAG), Tucson city residents wouldbe unfairly under-represented. If they wereelected, it might be difficult to adequately edu-cate voters about the qualifications of thesemanagers with highly technical responsibilities.People who generally support less governmentare opposed to increasing government powerover water. A change in state law would be re-quired to create such an agency as well as ap-proval of local governments and the voters. Forthis agency to acquire private water companiesa company would either have to be willing orbe acquired through condemnation. This ap-proach, while having some benefits, has gener-ally not been considered politically feasible.

TUCSON WATEROPERATIONAL OPTIONS

Some people have argued that private watercompanies should provide all water service inthe area, and that Tucson (or any government)should not be in the water business. They arguethat Tucson Water should privatize its opera-tions because this would distance a professionalservice from political decision-making. Theypoint out that Tucson Electric Power providespower very effectively as a stockholder-ownercorporation and that Tucson Water could dothe same. If it were a private water company,

the ACC would oversee water rates, not localpoliticians. Opponents argue that customersare better protected by officials they elect di-rectly and that a profit-making company wouldprobably have to charge higher rates. They alsoargue that if the company had to go throughcostly rate hearings, they would have to chargemore for water.

Others note that water is fundamentallydifferent from electricity, natural gas and otherutilities in ways that argue for public owner-ship. Water has public health, aesthetic, andenvironmental aspects that the others lack. Thepublic may be willing to pay more for watersupplies that are purer or sustainable, or to sub-sidize certain public uses or water. Thus, theprivate sector may not be the best provider.

Another option is to leave Tucson Waterunder city control, but have a private manage-ment company operate the facilities, ratherthan city employees. The City Council wouldcontinue to set policy, but would contract forservices as it does with its public transit system.The benefits are that the council would be lessinvolved in operational details, leaving that tooutside professional management which wouldprovide the services as contracted. Such a majortransition, however, could create problems inwater service, without necessarily improving it.

Another option is for Pima County to be-come the regional water provider, at least forthe water service area now served by TucsonWater, as it is now the primary regionalwastewater provider. This would require achange in state law to enable the county to takeon this new charge. The principal advantagewould be the enfranchising of Tucson Watercustomers outside city limits. This has generally

been considered politically infeasible as Tucsonlikely would be unwilling to give up this power.

Still another option is one that was pur-sued for years by Tucson Water; i.e., establishTucson Water as the only municipal water pro-vider in the region. During the 1960s and1970s, the city acquired numerous small watercompanies with the goal of providing unifiedwater management both inside and outside citylimits. Officials believed that one consolidatedwater system could better distribute water andcosts fairly among customers, perform more ef-fective water conservation programs and assureadequate water for fire protection in all areas.All companies were acquired through voluntarypurchases. One drawback of this system is thatit would serve a greater number of people who,because they live outside city limits, cannotvote on water matters that affect them.

ENFRANCHISINGNON-RESIDENTS

Because the voting public has such an im-portant influence on water decision making,having the right to vote on water matters is im-portant. Only Tucson city residents, however,may vote for City Council and mayor or castballots in water bond elections, water initiativesand referendums affecting Tucson Water. Manypeople who live outside city limits object tothis disenfranchisement. Meanwhile city resi-dents who do not receive water from the cityhave the right to vote on Tucson Water mat-ters.

If the city continues to be the major mu-nicipal water provider in the area, is there some


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way to enfranchise non-residents? Various billsto deal with this issue have been introduced inthe Legislature. The most recent one would giveACC responsibility for approval of water ratesfor people outside city limits. Opponents pointout that water rates could be very different in-side and outside the city, with rates outsideprobably increasing to cover the cost of going

through rate hearings. Current state law forbidsa municipality from charging substantiallymore to customers outside its limits; modestrate differences must be based on higher coststo deliver the water.

Most people would not consider it fair orlegal for non-residents to vote for city officialssince most decisions made by those officials are

unrelated to water matters; e.g., decisions thatimpact city taxes and services. Should all watercustomers vote on water bond issues, since wa-ter bonds are repaid not by taxes but by waterservice revenues? Should they be able to vote onwater initiatives and referenda? An argumentcan be made for these rights, but a change instate law probably would be required to enablea city to have an election outside city limits.


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As the above quote shows, the best watermanagers in the West have relied on imag-ination and creativity to get the most out

of a drop of water. Some may argue, however,that the quote describes a far simpler time thanthe present. Today, we use vast amounts of wa-ter for purposes frontiersmen never dreamed;we’ve become a bit more particular about waterquality, too.

In fact, if you have read the first sevenchapters of this report and aren’t confused bynow, then you haven’t been paying attention.Tucson’s water situation is a fiendishly com-plex, multi-dimensional conundrum. Eachpiece of the puzzle is linked to others, some inobvious ways, some in ways that are far moresubtle.

This complexity comes from the innate na-ture of the resource, as well as the relationshipsamong various factors. For instance, as a physi-cal resource, water involves disciplines rangingfrom chemistry and microbiology to civil engi-neering and hydrogeology. In a larger context,water resources are often tied to issues like pop-

ulation growth, property rights and quality oflife.

While individual aspects of a particular wa-ter issue may be well understood by the re-search community, the interactions are oftenpoorly understood. This is true within thephysical sciences, but is particularly acute whenthe interactions involve physical sciences, socialsciences and the humanities.

To further complicate matters, only a lim-ited community consensus exists on what weare trying to accomplish. We all want a reliable,bountiful, sustainable water supply. We de-mand that it be safe, palatable, and environ-mentally benign. And we want it provided toour homes, businesses and parks at the lowestpossible cost.

We also want fairness, or equity, as each ofus defines it. Here is where the consensus startsto break down. For some, equity means tradi-tional uses of water are favored. Others de-mand economic equity — those who benefit,pay. In practice, this might mean that thosecontinuing to pump groundwater should subsi-dize those who switch to renewable supplies.

Some want political equity — those who are af-fected, should decide. This would require newpolitical mechanisms whereby all water userscould vote on the candidates and initiativesthat determine their water future. And still oth-ers are concerned with inter-generational eq-uity. They don’t want today’s consumptiondecisions to limit the options and quality oflife of future Tucsonans.

We also would like less political strife overwater. This can tempt us to put off difficult de-cisions, perhaps by calling for yet anotherstudy. Groundwater overdraft is the sort ofproblem that is easy to ignore. A declining wa-ter table is out of sight and out of mind. Thereis no perceived sense of urgency, no hard dead-lines by which we absolutely must act. And soinaction becomes a tempting course.

As tempting and politically expedient as itmay be, inaction is itself a form of decision-making, but one rarely based on sound analysisor the expressed preferences of citizens. Thereare other compelling reasons to act soonerrather than later. Options may diminish over

111

AFTERWORD There was a whole folklore of water. People said a man had to make adipperful go as far as it would. You boiled sweet corn, say. Instead ofthrowing the water out, you washed the dishes in it. Then you washed

your hands in it a few times. Then you strained it through a cloth into theradiator of your car, and if your car should break down you didn’t justleave the water to evaporate in its gullet, but drained it out to water thesweet peas. Wallace Stegner, Wolf Willow, A History, a Story, and aMemory of the Last Plains Frontier.

time, or grow more expensive. Political costs of-ten rise over time, too.

The decisions we make, or avoid making inthe next few years are likely to have important,lasting consequences. Assuming we act, whoshould decide on our course? Are technocratsor self-appointed water experts best suited tomake the hard decisions? Not likely. The for-mer tend to have deep but narrow knowledge;the latter may offer appealingly simplistic butunproven solutions.

The authors of this report also decline tomake recommendations, for two reasons. First,some of the most informed water researchersare among the least certain of how to proceed.(We get confused at times, too.) Second, andmore importantly, physical and social scientistssimply have no basis for making policy deci-sions. These water resource issues aren’t aboutright and wrong decisions. They are about val-ues and priorities, expressed as choices with so-cial consequences.

Does that mean voters must directly decidedetails of our water strategy, as they have beenasked to do recently through initiatives? Is itfair or reasonable to expect a busy, preoccupiedelectorate to become informed on the nuancesof groundwater hydrology and the finer aspectsof alternative water purification systems?Clearly not. Rather, it is up to the technocratsto describe possible courses of action, and theirrespective costs and tradeoffs. Voters must ex-press their beliefs, values, and preferences withrespect to water. Then our elected officials mustdo the heavy lifting of turning this informa-tion into sound, long-term water policy.

How then can the reader help make deci-sions about Tucson’s water future? Part of the

process is examining your personal goals andvalues and then considering what options willbest achieve your objectives. No single “magicbullet” is available to assure a long-term,high-quality water supply. Most choices haveboth benefits and drawbacks.

BALANCING THE BUDGET

We invite you, the reader, to work througha series of options in order to shape your rec-ommendations to decision makers. We beginby restating the overdraft problem, and deter-mining how important achieving a sustainablewater supply is to you.

A simplified water balance was presented inbar chart form in the Preface (See page vi). Thisshows that in 1997, water demand in theTAMA totaled some 345,400 acre-feet. Renew-able supplies, consisting of natural groundwa-ter replenishment, CAP water, and effluenttotaled only 194,500 acre-feet, leaving a waterdeficit of 150,900 acre-feet of mined groundwa-ter.

A somewhat more detailed water budget isdepicted on the adjoining page. This informa-tion is graphically depicted as an “octopus” onthe following page. The top section of the waterbudget lists all water sources that contribute tothe aquifer, including natural, incidental, anddirect recharge. Gains to the aquifer also in-clude underground flow into our aquifer fromthe Santa Cruz AMA to the south. The centersection of this water budget tallies losses fromthe aquifer, which are mainly groundwaterpumping for municipal, industrial, and agricul-tural uses. Other losses from the aquifer in-clude underground flow from our aquifer into

the Pinal AMA to the north, andevapotranspiration from shallow groundwater.

The bottom portion of the budget repre-sents direct uses of effluent and CAP water,which are renewable supplies. While these usesdo not directly affect the aquifer balance, theremay be indirect impacts. For example, if CAPwater was not available to irrigate some agricul-tural land, groundwater might be used instead.On the other hand, effluent not used to irrigatea golf course might be left in the riverbed,where much of it would become incidental re-charge to the aquifer.

The bottom line of this water budget is thesame as in the bar chart in the introduction —we are pumping far more groundwater than isbeing replaced in the aquifer. This situation isnot sustainable in the long run. The only op-tions for approaching or attainingsustainability are making full use of our CAPallocation, severely limiting current and futurewater demand, or some combination of thetwo.

TO SUSTAINOR NOT TO SUSTAIN

How important is a sustainable water sup-ply to you? Sustainability is not anall-or-nothing concept. When using our watersupply, we have a range of choices, includingthe following:

• Try to balance water supply and water de-mand to guarantee water availability indefi-nitely;

• Try to prolong the life of the water supplyover a shorter term, say 50 or 100 years;


112

Afterword

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• Plan to deplete some parts of the aquifer(Avra Valley, for example) while protecting thecentral city from subsidence; or

• Use as much water as we want for as longas it lasts.

Current state law directs us to aim towardsprolonging the supply into the future, but doesnot require complete sustainability. This is be-

cause “Safe yield” allows a certain amount ofgroundwater mining.

People who support sustainability or pro-longing the life of the water supply are mainlyconcerned about:

• Avoiding subsidence;• Assuring an affordable water supply for fu-

ture generations;

• Assuring water quality for future genera-tions;

• Complying with requirements of state law;• Preserving the desert from “urban sprawl”

or “overdevelopment.”People who don’t support sustainability

usually feel that:• The present is more important than the

distant future;• New technologies may be developed over

time to solve the problem;• The problem is too far off to be a concern;• Information about water supplies and wa-

ter quality is incomplete or not credible;• Their family may not be here when the

problems arise;Do you recognize your views in either list?

Or do you identify with some statements fromboth lists? How much do you value a sustain-able water supply? What kind of limitations areyou willing to impose on others? What sacri-fices are you willing to make?

WATER BUDGET SCENARIOS

Conventional wisdom is that most peoplein the community support either a sustainablesupply or at least prolonging our supply. Butthere are many divergent views as how best toapproach this goal. To balance supply and de-mand we can control water use and/or increasethe supply. We can control water use by limit-ing the number of people using water and/orlimiting the amount each person uses. We canalso transfer water use from one sector to an-other (e.g., reduce agricultural activities to savewater for other uses). Water supplies can be in-creased by capturing more rainwater and snow


114

Water budget flow chart. (1997 data)

Sources: Arizona Department of Water Resources, Water Resources Research Center.

Afterword

115

Supply & Demand Scenarios*

Based upon Approximate Current Levels of Demand by Sector, in Acre-Feet

Demand (% of current) Groundwater Pumping

Muni. Indus. Ag. Supply Muni. Indus. Ag. Total CAP Balance†

100 100 100 Groundwater for all sectors 150,000 50,000 125,000 325,000 0 -180,000

100 100 100 Groundwater for municipal, CAP for others 150,000 0 0 150,000 175,000 -5,000

100 100 100 CAP for municipal, groundwater for others 0 50,000 125,000 175,000 150,000 -30,000



200 100 100 CAP for municipal, groundwater for others 0 50,000 125,000 175,000 300,000 +27,000



200 50 50 CAP for municipal, groundwater for others 0 25,000 62,500 87,500 300,000 +99,000

200 50 50 Half groundwater, half CAP for all sectors 150,000 12,500 31,300 193,800 193,800 -7,000



200 200 200 CAP for municipal, groundwater for others 0 100,000 250,000 350,000 300,000 -117,000

200 200 200 Half groundwater, half CAP for all sectors 150,000 50,000 125,000 325,000 325,000 -92,000

* This table represents a range of supply and demand scenarios for general illustration; it should not be used to make specific future projections. Simplifiedassumptions (e.g. all groundwater or all CAP for a sector) have been made to clarify the relationships between supply, demand and the aquifer balance.

† This number represents the approximate “wet water” loss or gain to the regional aquifer. The value is calculated as: (net natural recharge [76,600]) - (groundwateroutflow [24,500]) - (evapotranspiration [3,700]) - (groundwater pumping) + (incidental recharge) + (groundwater inflow [8,700]). Incidental recharge is itselfcalculated as 38% of municipal demand (multi-year average), 20% of agricultural demand, and 12% of industrial demand. This balance does not consider factorssuch as long-term storage through recharge, or changes in incidental recharge rates.

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melt, importing and using water from else-where and accepting wastewater as a supply formore uses.

Here is where you bring it all together,combining the factual information gleanedfrom the first seven chapters with your valuesand preferences, to generate tentative choices.The final step is to see what the consequencesof those choices are, and how your choices in-teract with each other. To do that, we use waterbudget scenarios.

The table on the preceding page shows tenillustrative water supply and demand scenarios.The left side of the table shows municipal, in-dustrial and agricultural demand expressed aspercentages of current demand. The “supply”column describes who pumps groundwater andwho uses CAP water under each scenario. (Notethat use of effluent has little effect on the waterbudget bottom line, because nearly all effluentnot re-used is directly or incidentally re-charged.) These assumptions about water de-mand levels and supply allocations on the leftside of the table are used to estimate resultinggroundwater pumping by sector, CAP usage,

and aquifer balance, as shown on the right sideof the table.

The first three scenarios hold demand atcurrent levels. The first scenario shows that ifeveryone uses pumped groundwater, we have alarge deficit in the aquifer. The second scenariosuggests that if all growth were halted andgroundwater were reserved solely for municipaluses, the aquifer would be nearly in balance.The next three scenarios correspond to an even-tual doubling of municipal demand, as popula-tion grows. Here, reserving groundwater formunicipal uses does not bring the aquifer closeto balance. By contrast, using CAP water for allmunicipal uses actually produces a surplus inthe aquifer.

The third set of scenarios combines munic-ipal growth with a halving of industrial and ag-ricultural demand. Note that serving a 50-50blend of groundwater and CAP water to all sec-tors nearly balances the aquifer. The final set ofscenarios corresponds to a doubling of waterdemand in all sectors. This could occur, for ex-ample, if population growth continued un-abated, mining expanded, and tribal waterallocations were used to expand irrigated agri-

culture on reservation lands. In such a situa-tion, there is not sufficient CAP water availableto bring the aquifer close to balance.

Those of you with Internet access are nowinvited to try your hand at water budgeting bymaking your own assumptions. An interactiveversion of this budget is on the Web at:

http://ag.arizona.edu/AZWATER/Use it to construct a scenario that reflects

your values, preferences and sense of fairness.Try out a number of options. For example, youmay want to limit water use by controllingpopulation, or by requiring more conservation;or you may want to lessen long-term salinityproblems by using less CAP water.

See how close your preferred options cometo balancing supply and demand. Rememberthat if you make some changes, other figureswill be affected. For example, if you eliminateagriculture and replace it with naturally vege-tated park land, the water savings will begreater than if you replace it with golf courses.If you use more effluent, you will have less inci-dental recharge. To get close to watersustainability, you will have to make hardchoices. When push comes to shove, where areyou willing to compromise?


116

Acre-foot (a.f.) - The amount of waterneeded to cover an acre of land one foot deep,equal to 325,851 gallons.

Algae - Aquatic one- or multi-celled plantswithout true stems, roots and leaves butcontaining chlorophyll. Algae may producetaste and odor problems.

Alluvium - Debris from erosion, consistingof some mixture of clay particles, sand, pebbles,and larger rocks. Usually a good porous storagemedium for groundwater.

Artesian well - A well in which water risesto the surface without pumping from apermeable geological formation that is overlainby an impermeable formation. No artesianwells remain in the Tucson area.

Artificial recharge - The deliberate act ofadding water to a groundwater aquifer bymeans of a recharge project. Artificial rechargecan be accomplished via injection wells,spreading basins, or in-stream projects. See alsoincidental recharge, natural recharge, recharge.

Aquifer - One or more geologic formationscontaining enough saturated porous andpermeable material to transmit water at a ratesufficient to feed a spring or for economicextraction by a well. Combination of two Latinwords, aqua or water, and ferre, to bring;literally, something that brings water.

Assured Water Supply - A technical termused in the Groundwater Management Actdefined as a supply of water theoreticallysufficient to meet the needs of a newdevelopment or customers of a municipal water

supplier for 100 years. The methods fordetermining this are spelled out inAACR12-15-701.

Augmentation - Supplementing the watersupply by such means as importing water fromanother basin or storing water.

Base flow - Streamflow derived fromgroundwater seepage into the stream; water thatflows on the surface independent ofprecipitation.

Basin - See Groundwater basin.Ccf (hundred cubic feet) - a unit of water used

by some municipal water providers for meteringand billing purposes. 1 Ccf = 748 gallons.

Central Arizona Project (CAP) - A facilityconsisting of canals, pumping stations andpipelines used to transport water from theColorado River at Lake Havasu to CentralArizona and ultimately to Tucson.

CERCLA - The ComprehensiveEnvironmental Response, Compensation andLiability Act, commonly known as Superfund,which regulates disposal and cleanup ofhazardous materials.

Chloramine - A chemical used to disinfectand innoculate water supplies. Formed bycombining chlorine and ammonia, chloramineis generally more stable but less potent thanchlorine.

Chlorine - A chemical commonly used todisinfect water. It is highly effective againstalgae, bacteria and viruses, but not protozoa.

Coliform bacteria - a common type ofbacteria found in soil and water and which

grows in the intestines of warm-bloodedanimals. They are generally not harmful, buthigh levels may indicate the presence of otherharmful bacteria or viruses.

Cone of depression - A drop in the watertable around a well or wells which have beenpumping groundwater. Depending on the rateof pumping and aquifer characteristics a coneof depression can be shallow and extend only afew feet or it can extent for several miles. Sincewater flows downhill underground, a cone ofdepression pulls water from the surroundingarea into it, thus affecting the nearby watertable.

Constructed wetland - A manmade wetland,usually designed to utilize wastewater and ofteninvolving a wildlife habitat component.

Consumptive use - A use that makes waterunavailable for other uses, usually bypermanently removing it from local surface orgroundwater storage as the result ofevaporation and/or transpiration. Does notinclude evaporative losses from bodies of water.Compare with non-consumptive use.

Corrosivity - A measure of the ability ofwater to corrode pipes. Corrosion occurs whenmetal is exposed to conditions which cause thebreakdown of the metal through an exchangeof ions. If corrosion is severe enough, the pipesmay break entirely. EPA has no standards forcorrosivity.

Desalinization - A process of removing saltsand other dissolved minerals from water.

117

Appendix AWATER TERMS

Disinfection byproducts - Compoundsformed from the interaction of treatmentchemicals with materials (usually organic) inthe water.

Distribution system - An interconnectedgrid of water mains, valves, storage reservoirsand pressure boosting or reducing facilities.

Downgradient - The direction water flows byforce of gravity.

Drawdown - A lowering of the groundwaterlevel or the piezometric pressure caused bypumping, measured as the difference betweenthe original groundwater level and the levelafter a period of pumping.

Effluent - Water that has been collected in asewer for subsequent treatment (ADWRdefinition). The term is also commonly used torefer to water discharged from a treatmentplant.

Evapotranspiration - The amount of watertranspired through pores and evaporated byvegetation.

Electrodialysis - a membrane filtration processthat uses an electric charge rather than waterpressure to force dissolved solids through themembrane pores. Used by Buckeye, AZ.

Filtration - The process of passing waterthrough materials with very small holes (pores)to strain out particles. Filtration can removemicroorganisms including algae, bacteria andprotozoa, but not viruses.

Flexibility Account - A paper account inwhich farmers can accumulate credits forunused portions of their groundwaterallotments for use in meeting conservationrequirements in the future.

Floodplain - The area near a watercourseinundated during floods. The 100-yearfloodplain is the area that is expected to beinundated by a flood of a magnitude that has aone-in-a-hundred probability of occurrig in anyyear.

GPCD (Gallons per capita per day) - Theamount of water used on average by an

individual each day. Total gpcd is calculated bydividing total water use in the area, includingindustrial and commercial uses, by the numberof users. Residential gpcd is the numberresulting from only considering domestic wateruse.

Gradient, hydraulic - The change of pressureper unit distance from one point to another inan aquifer. When an area is said to be“downgradient” it is at a lower level and waterwill flow in that direction.

Groundwater - Subsurface water body in thezone of saturation, or more commonly,available groundwater is defined as: Thatportion of the water beneath the surface of theearth that can be collected with wells, tunnels,or drainage galleries, or that flows naturally tothe earth’s surface via seeps or springs.

Groundwater basin - An area enclosing arelatively distinct hydrologic body or relatedbodies of groundwater.

Groundwater savings facility (GSF) - Afacility, usually a farm, which agrees to use arenewable water supply such as CAP waterinstead of groundwater under the UWSprogram. Entities with extra renewable supplies,such as municipal water providers, sell CAPwater to the farms and in return get a credit forgroundwater saved, which can be used to offsetfuture groundwater pumping.

Hardness- A water quality parameter thatindicates the level of alkaline salts, principallycalcium, magnesium, and iron, and expressedas equivalent calcium carbonate (CaCO3). Hardwater is commonly recognized by the increasedquantities of soap, detergent or shampoonecessary to raise a lather.

Hydraulic gradient - see gradient, hydraulic.In-lieu recharge - A term used by ADWR to

describe the process of using a renewablesupply instead of pumping groundwater at aGroundwater Savings Facility. No water isactually recharged.

Impact fee - A fee charged to developers tocover part or all of the costs of providingservices, such as sewers, water connections, androads. Such a fee is allowed but not requiredunder state law.

Incidental recharge - Water incidentallyadded to a groundwater aquifer due to humanactivities, such as excess irrigation water appliedto fields or water discharged as waste after ause. See also recharge, artificial recharge,natural recharge.

Infiltration - The process of water enteringthe soil or streambed surface.

Injection well - An artificial structure(usually an existing well) used to recharge thewater table by forcing water down the well.

Irrigation district - A political entity createdto secure and distribute water supplies. Mostirrigation districts provide water for irrigationon farms, but some which originated foragricultural purposes now primarily servemunicipal customers.

mg/l - Milligrams per liter - Roughlyequivalent to parts per million (see below).

Microfiltration (uf) - a form of filtrationusing a membrane with larger pores thannanofiltration. It is highly effective inremoving pathogens, including parasites suchas giardia, but does not remove salts. Because ithas large pores, UF does not leave a salineconcentrate, although filters must bebackwashed to keep the pores open.

Mineral content - See Total dissolved solids.Mountain front recharge - Natural recharge

that occurs at the base of the mountainsbecause of rainfall or snow melt at higherelevations.

Municipal water use - All non-irrigationuses of water supplied by a city, town, privatewater company or irrigation district. Generallyincludes domestic, commercial, public andsome industrial uses.


118

Nanofiltration (NF) - A form of filtrationusing membranes with larger pores than reverseosmosis. NF removes most salts, pathogensand organics. Like RO the process requirespretreatment of water with chemicals or asand-based system. NF has not been usedcommercially on a large scale for drinkingwater.

Natural recharge - Natural replenishmentof an aquifer generally from snowmelt andstorm runoff. See also recharge, artificialrecharge, incidental recharge.

Ozone - A highly reactive form of oxygen(O3) used to disinfect water.

Non-consumptive use - A water use thatleaves the water available for other potentialuses, usually after it has been collected in asewage system. Most indoor uses are largelynon-consumptive. Compare with consumptiveuse.

Parts per million (ppm) and parts per billion(ppb)- A measures of the concentration ofmaterials in a liquid, often used to describe thedegree of contamination of water. One ppmindicates that for each one millions units ofwater there is one unit of the contaminant,One ppb indicates that for each one billionunits of water there is one unit of thecontaminant. 1 ppm is approximately equal to1 mg/L.

Permeability - A measure of the relative easewith which a porous medium can transmit aliquid under a potential gradient.

pH - A measure of the relative acidity ofwater. Below 7 is increasingly acid, 7 is neutraland above 7 is increasingly alkaline.

Potable water - Water that is suitable fordrinking, from a Latin word meaning “drink.”

Primary treatment - Initial treatment givento sewage, usually removal of solids andpossibly some disinfection.

Private water utility - A water provider thatis owned by individuals or a corporation andsells water to customers.

Protozoa - Microscopic animals that occuras single cells. Some can cause disease inhumans. They are not destroyed bydisinfection, but can be destroyed by filtration.

Public utility - A water or power providerowned by a government such as a city or town.

Recharge - Augmentation of thegroundwater by the addition of water. Seenatural recharge, artificial recharge, incidentalrecharge.

Reclaimed water - Tertiary-treated wateravailable for use on turf or other facilities.

Reservoir - A facility for storing water untilit is to be used. A reservoir may be open orcovered.

Reverse osmosis - A process whereby wateris forced through membranes that containholes so small that even salts cannot passthrough them. It removes microorganisms,organic chemicals and inorganic chemicals,producing very pure water.

Runoff - Drainage or flood discharge whichleaves an area as surface flow or as pipelineflow, having reached a channel or pipeline byeither surface or sub-surface routes.

Safe yield - A groundwater managementgoal which attempts to achieve and thereaftermaintain a long-term balance between theannual amount of groundwater withdrawn inan Active Management Area and the annualamount of natural and artificial rechargewithin a designated area.

Secondary treatment - The most commonlevel of treatment of sewage, involving removalof solids, use of bacterial action forpurification, and the addition of disinfectants.

Service area - The area served by amunicipal water provider, within which it mayhold a monopoly.

Sewage - Water that has been used byindividuals or businesses and needs treatment.

Sewer - A pipeline used to transport sewageto a treatment facility.

Sludge - Solids left over from thewastewater treatment process.

Sodium - A mineral which occurs naturallyin most water.

Soft water - Water with relatively lowconcentrations of certain dissolved minerals,principally calcium, magnesium, and iron.Water from which these minerals have beenmostly removed, usually through an ionexchange process.

Soil-aquifer treatment - A method oftreating water by letting it seep through soiland other materials to mitigate pollution.

Subsidence - Downward movement of theland surface associated with groundwaterpumping, especially where such pumpingexceeds safe yield and the water table hasdropped. Uneven rates of subsidence over anarea can lead to differential subsidence, whichcan cause lateral movement of the land surface,and cracks and fissures to appear. This is morelikely to occur in areas where the aquifer variesin thickness, such as near the edges ofgroundwater basins. Subsidence is an essentiallyirreversible process, not greatly ameliorated bylater raising the water table.

Subsurface water - All water below the landsurface, including soil moisture, capillary fringewater in the vadose zone, and groundwater.

Superfund - A commonly used name forthe federal Comprehensive EnvironmentalResponse, Compensation and Liability Act(CERCLA).

Surface water - Water that flows on thesurface in streams.

Terminal storage - A facility for storage ofwater near the end of a pipeline or canal. Afacility to be used in times of water shortage inthe CAP system (due, for example, to damageto the canal), that would supply water during aperiod of system repair or while wells are beingreactivated.

Appendix A Water Terms and Acronyms

119

Trichloroethylene (TCE) - A compoundused most often for degreasing metal partsduring manufacturing. Found as a pollutant insome Tucson-area groundwater, suspected ofcausing certain serious diseases.

Trihalomethanes (THMs) - Disinfectionbyproducts arising from the combination ofchlorine with organic matter in the water.

Tertiary treatment - Post-secondarytreatment of water designed to improve thequality of the water to the point where it canbe put to a particular beneficial use.

Total dissolved solids (TDS) - A measure ofthe minerals dissolved in water. Up to 500 ppmis considered satisfactory and above that levelincreasingly unsuitable for domestic use.Tucson-area groundwater generally has TDSlevels between 200 and 600 ppm; CAP waterhas TDS of about 700 ppm.

Transmissibility - The flow capacity of anaquifer measured in volume per unit time perunit width. Equal to the product ofpermeability times the saturated thickness ofthe aquifer.

Transmission line - A pipeline fortransporting water.

Treated wastewater - The treated water thatcomes from a sewage treatment plant.

Treatment plant - A facility using variousphysical and chemical processes for treatingwater or wastewater. Treatment can includedisinfection, filtration, adjusting the pH,adding corrosion inhibitors, and improvingtaste and odor.

Turbidity - The reduction of transparencyin water due to the presence of suspendedparticles, or a cloudy appearance in the water.Increased turbidity raises the risk ofwater-borne pathogens growing andreproducing. Turbid water is therefore moredifficult to disinfect.

Underground storage facility (USF) - Afacility for artificial recharge of water suppliesinto an aquifer.

Underground Water Storage, Savings, andReplenishment Program (UWS) - A programadministered by the ADWR to encourage thestorage and/or use of renewable supplies. Rulesgoverning permitting and operation of

Underground Storage Facilities andGroundwater Savings Facilities are describedunder this program.

Vadose zone - The unsaturated zone lyingbetween the earth’s surface and groundwatertable.

Volatile organic compounds (VOCs) -Solvents used as degreasers or cleaning agents.They evaporate easily producing odors typicalof gasoline, kerosene, lighter fluid or drycleaning fluid. Some may be cancer-causing.

Water main - A large pipeline whichtransports water to smaller distribution lineswhich take water to homes and businesses.

Water table - The upper boundary of a freegroundwater body, at atmospheric pressure.

Wellfield - A group of wells in a particulargeographic area, usually operated by one entity.

Wetlands - An area that always has water ator near the surface. A natural wetland receivesits water from a groundwater source and is alsocalled a “cienega”. A constructed, or artificial,wetland usually receives its water from somewastewater source, either agricultural, industrialor municipal.


120

ACC - Arizona Corporation Commission

ADEQ - Arizona Department of EnvironmentalQuality

ADWR - Arizona Department of Water Resources

AMA - Active Management Area

APP - Aquifer Protection Permit

AVID - Avra Valley Irrigation District

AWBA - Arizona Water Banking Authority

AWS - Assured Water Supply

BADCT - Best Available Demonstrated ControlTechnology

BMP - Best Management Practice

CAP - Central Arizona Project

CAGRD - Central Arizona GroundwaterReplenishment District

CAVSARP - Central Avra Valley Storage andRecovery Project

CAWCD - Central Arizona Water ConservationDistrict

CMID - Cortaro Marana Irrigation District

DES - Arizona Department of Economic Security

DDT - Dichloro-Diphenyl-Trichloroethane

EA - Environmental Assessment

EIS - Environmental Impact Statement

EPA - U.S. Environmental Protection Agency

ED - Electrodialysis

ESA - Endangered Species Act

FCD - Flood Control District

FEMA - Federal Emergency Management Agency

FICO - Farmers Investment Company

GMA - Arizona Groundwater Management

Act of 1980

GPCD - Gallons Per Capita per Day

GPM - Gallons Per Minute

GSF - Groundwater Savings Facility

INA - Irrigation Non-Expansion Area

MF - Microfiltration

NF - Nanofiltration

NPDES - Non Point Discharge Elimination System

PAG - Pima Association of Governments

PCE - Perchloroethylene

PCHD - Pima County Health Department

PDEQ - Pima County Department ofEnvironmental Quality

RO - Reverse Osmosis

SAT - Soil-Aquifer Treatment

SAWRSA - Southern Arizona Water RightsSettlement Act

TARP - Tucson Airport Remediation Project

TAMA - Tucson Active Management Area

TCE - Trichloroethylene

TDS - Total Dissolved Solids

THM - Trihalomethane

TSMP - Tucson Stormwater Management Plan

USF - Underground Storage Facility

USGS - United States Geological Survey

UWS - Underground Water Storage, Savings, andReplenishment Program

VOCs - Volatile Organic Compounds

Water CASA - Water Conservation Alliance ofSouthern Arizona

WCPA - Water Consumer Protection Act

WRRC - Water Resources Research Center

121

Appendix A Water Terms and Acronyms

ACRONYMS

123

Appendix BSUPPLEMENTARY INFORMATION

CONTENTS

Water Providers in Pima County . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124Effluent Use Alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126Rate Structure For Tucson Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127Water Bills for Selected Arizona Water Providers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129National Primary Drinking Water Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1301999 Water Rate Schedule for the Central Arizona Project. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137CAP Water Subcontract Amounts in the Tucson AMA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138The Water Consumer Protection Act . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139

Water System Population ServedA-A RV Campground 100

ADOC-Correction Training 3700

ADOT Canoa R/A 1375

Ajo Domestic Water Improvement 2190

Amity Circle Tree Ranch 150

Amphitheater School District 10,615

Arivaca Townsite Water Co 240

ASARCO Silver Bell Unit 930

Avra Water Coop, Inc 3,300

AZ Parks Board-Catalina St 400

AZ Portland Cement-plant 160

AZ Water Co-Ajo 2,000

Bermuda Gardens Trailer 93

Breakers Water Park 533

C & N Water Co 32

Cactus Country Tr Haven 250

Mt. Lemmon Camps 850

Campbell Estates 300

Canada Hills Water Co 5,012

Canyon Ranch 485

Carol Anne Dr Homeowners 52

Casa Motel & Camping 30

Casitas De Castilian 200

Catalina Country Mobile 130

Caterpillar Water 65

Colonial Mobile & Trailer 150

Community Water - Green Valley 12,320

Continental School 250

Coronado Forest Drive In 40

Cortaro Acres Home 30

Cortaro Water Users Assn 1,920

Cyprus Sierrita Corp 760

Decker Community Water Co 29

Deep Well Cooperative 40

Del Lago Water Co 990

Desert Hills School 107

Desert Shores MHP 405

Desert Water Well Coop S 45

Desert Willows MHP 320

Diamond Grove Mobile HE 208

Dome Well Association 27

DYTR-Catalina Mountain 450

E & T Water Co 800

Elkhorn Ranch 50

Emery Park Mobile Home Pk 240

Evergreen Cemetery 35

Exxon Corporation 200

Far Horizons East 1,500

Far Horizons Mobile Home 290

Farmers Water 2,389

Federal Corr Institute 750

Flowing Wells Irrigation District 16,160

Foothills Mobile Homes 95

Forty-Niners Water Company 790

Francesca Water Company 100

Fred’s Arena Bar & Steak 40

Green Valley Water Company 8,125

Greenfields School 250

Gringo Pass Trailer Park 55

Halcyon Acres 400

Halfway Station MHP 64

High Chaparral Water Coop 35

Hohokam Mobile Home Park 60

Homeowners Coop 45

Hub Water Co 4,040

Hughes Missile Systems Co 4,000

IBM 3,100

I M Water Co Inc 340

King’s Trailer Lodge 45

Kino Mobile Home Park 110

Kitt Peak National Observatory 300

La Casita Water Co 25

La Cholla Air Park Ed Pr 200

Lago Del Oro Water Co 4,500

Lakewood Estates Water C 750

Las Quintas Serenas WC 1,169

Manor Trailer CC 170

Marana Water Service Inc 1,715

Mesaland Water Co-op 350

MDWID - Metropolitan Domestic Water

Improvement District 36,250

Midvale Farms Water Company 200

Mirabell Water Coop 210

Mission Palms Apartments 900

Mr G’s Diner 50

Mt Lemmon Water Co 600


124

WATER PROVIDERS IN PIMA COUNTY

Following is a list of water providers in Pima County registered with the Environmental Protection Agency in 1998. Note that some are schools orbusinesses providing water only during certain hours. If some of the following population numbers do not agree with those in the text, its becausethey may represent different years.

Water System Population ServedNorth La Cholla MHP 100

Oracle Villa Apartments 822

Orchard Valley MHP 80

Organ Pipe NM-Headquarters 412

Pacific Fruit Express 50

Palm Vista Estates MHP 400

Pantano Water Coop 98

Pima County Parks 9,142

Pima Cnty Dot Avra Valle 106

Pima Ramada Mobile Home Park 35

Pita Water 38

Quail Creek Water 180

Quail Valley Tennis Club 40

Rabies Control Center 20

Rainbow Tavern 51

Raindance Water Coop 60

Rancho De La Osa 40

Rancho Del Conejo Water 522

Rancho Los Amigos MHP 200

Rancho Sierrita Well Assc 102

Rancho Tierra Blanca 40

Rancho Vistoso Water Co 4,300

Ranchwood Mobile Park 200

Ray Water Co Lansing Str 2,880

Regina Cleri Center 25

Rillito Water Users Assoc 200

Rincon Country East Rv re 920

Rincon Mesa Landowner’s 65

Rincon Ranch Estates Water Co 905

Rincon Water Co 50

Rio Vista Mobile Home Pa 2000

Riverside Apts 10

Saguaro National Park 420

Saguaro Water Company 35

Sahuarita Heights Mobile 110

Sahuarita Sch, Dist 3, 1,800

Sahuarita Village Water 135

Sahurita Park Pcpr 40

Salpointe High School1 288

Samalayucca Improvement 150

Sandario Water Co 555

Santa Catalina Mission Church 100

Sasabe Border Water Co 68

Shae Water Company 28

Sierra Court Trailer Park 100

Sierra Tucson 100

Sierrita Foothills 50

Sierrita Mountain Water 80

Siete Casas Joint Venture 60

Silver Cholla Park 200

Sleepy Hollow MHP 1,110

Solana & Sombra MHP 200

Soldier Camp Permittees 50

Sopori Elementary School 300

Southern Pines Baptist Church 100

Spanish Trail Water Co 770

St Joseph’s Hospital 1,400

Su Casa MHP 100

Summit Water Company 33

Summit Water Coop 78

Tanque Verde Guest Ranch 40

Terminal Stations 500

The Lazy Bone RV Resort 300

Thim Utility Company 828

Thunderhead Ranch 93

Town & Country MHP 640

Town of Oro Valley Water 10,850

Tra-tel Tucson RV Park 50

Tucson Electric Power Co 550

Tucson General Hospital 500

Tucson Meadows MHP 650

Tucson Medical Center 2,500

Tucson Racquet Club 400

Tucson Rock 40

Tucson Rock and Sand 40

Tucson Water Dept 55,3040

University of Arizona 1,5950

Universal Ranch Store 8

USAF-Davis Monthan AFB 8,900

United States Forest Service 950

Vail School 110

Val Verde Inc 45

Valle Verde Del Norte 300

Veterans Medical Center 900

Via Verde West MHP 100

Villa Capri Trailer Park 420

Vision Quest Annex 30

Vista Del Norte TP 750

Voyager Water Company 2,500

Webb’s Steak House 60

Wells Fargo Well Assoc 80

White Stallion Guest Ran 45

Wildflower Water Co-op 84

Winter Haven Ranch 125

Winterhaven Water & Dev 765

Wycliffe Mountain Vista 26

Zimmerman Enterprises 200

Appendix B. Supplementary Information

125

Source: U.S. Environmental Protection Agency Web Site: www.epa.gov

What happens to effluent today?

1. Santa Cruz River discharge. This represents the existing condi-tions and incidental recharge.

2. City of Tucson Reclaimed Water System. Direct use of tertiaryeffluent.

3. Agricultural irrigation. The reuse of treated secondary effluent forthe irrigation of non-food agriculture.

ALTERNATIVES — IN PROGRESS

1. Santa Cruz River Managed Underground Storage Facility (RogerRoad to Ina Road). Acquiring credits for existing discharge which is re-charging the aquifer.

2. Santa Cruz River Managed Underground Storage Facility (InaRoad to Red Rock). Acquiring credits for existing discharge which is re-charging the aquifer.

3. Rillito/Swan Effluent Wetland Recharge. This project involves ad-ditional treatment and constructed recharge.

4. Kino Effluent Wetland Recharge. This project combines the directreuse of reclaimed water for turf irrigation with a constructed rechargeoperation.

5. Marana High Plains Effluent Recharge Project. Constructed re-charge and vegetation enhancement.

6. Atturbury Wash Project. Wetlands treatment and dry well rechargeat Lincoln Regional Park in the west tributary of Atturbury Wash.

7. Lower Santa Cruz Replenishment Project located north of AvraValley Road. Direct recharge using basins and streambed.

FUTURE/PROPOSED ALTERNATIVES

1. Santa Cruz River Managed Underground Storage Facility, 100percent credit accrual for SAWRSA effluent. Managed recharge RogerRoad to Red Rock.

2. Wastewater reclamation in Oro Valley and Metro Water service ar-eas. This project would include a wastewater reclamation facility and ef-fluent lines to existing and planned golf courses or, possibly, to rechargebasins.

3. Effluent Reuse in Green Valley. The project would involve the useof effluent for golf course turf irrigation and agricultural irrigation.

4. Avra Valley Wetlands Treatment and Effluent Recharge Project.Wetlands treatment and basin recharge.

5. Marana Santa Cruz River Park and Recharge Project. This projectprovides for a combination of facilities including constructed and man-aged recharge facilities and turf areas for irrigation reuse. Located atCortaro Farms Road and the Santa Cruz River.

6. Tangerine Road Wastewater Pollution Control Facility.7. Pascua Yaqui Golf Course and Pascua Yaqui Recharge Projects.8. Harrison-Pantano water reclamation facility. Reclamation facility

that will provide effluent suitable for reuse, recharge or discharge toPantano Wash.

9. Kolb/Bilby water Reclamation Facility. Reclamation facility thatwill provide effluent suitable for reuse, recharge or discharge to a nearbywatercourse. The proposed site is in the vicinity of Kolb and Bilby Road.

10. Santa Cruz River downtown enhancement.


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EFFLUENT USE ALTERNATIVES

Following is a list of effluent projects and potential alternatives as of January 1999, compiled by the Regional Effluent Planning Partnership.

Minimum ChargeThe minimum charge for all metered accounts is based upon the meter size and is levied whether or not any water is used. The charge includes

a 3 Ccf minimum usage allowance for all customer classes except for sub-metered mobile home parks which receive a minimum usage allowancebased on the number of occupied units. The monthly minimum charges are as follows:

Service Charge Meter Size (inches) Service Charge ($)

0.75 $ 5.301.00 $ 6.401.50 $ 9.502.00 $ 14.002.50 $ 20.003.00 $ 25.004.00 $ 42.006.00 $ 82.008.00 $ 123.00

10.00 $ 185.0012.00 $ 305.00

Usage ChargeThe usage charge for all metered accounts is based upon the actual water utilized by the customer between monthly meter readings in excess

of the minimum water use allowance. Charges for non-residential customers are further divided between winter and summer rate schedules. Winterrates are applicable to water usage from November through April. Summer rates are applicable to water usage from May through October.

For customers in the Multifamily, Submetered Mobile Home Park, Commercial, and Industrial customer classes, a two-tiered summer sur-charge is charged for water usage above the customer’s average monthly water usage for the previous winter rate period (November - April). Tier 1 ischarged on all water used during the month which exceeds the customer’s monthly winter average usage. Tier 2 is an additional charge on all waterused during the month which exceeds 150 percent of the customer’s monthly winter average usage. All charges identified below are based upon wateruse in units of Ccf (100 cubic feet). One Ccf equals 748 gallons.


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RATE STRUCTURE FOR TUCSON WATER

Tucson Water’s charges (as of summer 1999) for delivery of potable water are comprised of four basic components: Minimum Charge, UsageCharge, Isolated Area Service Charge, and CAP Charge. Each of the components and its specific rate schedules is discussed in the following section.Tucson Water bills its customers on a monthly basis; all charges shown are monthly charges.

Customer Class/Charge Amount (Ccf) Winter ($/Ccf) Summer ($/Ccf)Residential - single family 0 - 3 0.00 0.00

4 - 15 1.62 1.62

16 - 30 2.61 2.61

over 30 3.29 3.29

Duplex-Triplex 0 - 3 0.00 0.00

4 - 20 1.62 1.62

21 - 35 2.61 2.61

over 35 3.29 3.29

Multi-family 0 - 3 0.00 0.00

over 3 1.35 1.35

summer surcharge - tier 1 0.95


maximum charge per Ccf 2.55

Submetered mobile 0 - 3 0.00 0.00

home parks over 3 1.35 1.35




Commercial 0 - 3 0.00 0.00

over 3 1.40 1.40




Industrial 0 - 3 0.00 0.00

over 3 1.21 1.21




Construction 0 - 3 0.00 0.00

over 3 1.89 1.89

Isolated Area Service ChargeFor water customers who are located in water delivery areas that are isolated and not connected to Tucson Water’s central service area, an isolated area service

charge is applied to each Ccf of monthly water usage to cover the higher costs of providing water to these isolated areas. The rates are $0.35/Ccf.

CAP ChargeAll Tucson Water customers are charged a CAP fee applied to each Ccf of monthly water usage. This charge contributes to covering costs associated with the

Central Arizona Project. The rates are $0.02/Ccf.

Source: Tucson Water Web Site: http://www.ci.tucson.az.us/water/tsnwtr/rates/rate99.htm


128


129

WATER BILLS FOR SELECTED ARIZONA WATER PROVIDERS

153.52

101.25

75.20

62.35

74.09

61.19

54.79

51.37

44.33

73.76

50.45

37.11

39.24

46.40

59.28

41.13

25.37

28.96

67.28

37.00

36.95

36.40

35.55

25.99

25.99

25.42

24.58

21.50

21.70

21.06

20.34

20.30

16.64

12.79

12.47

12.12

0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00 180.00

*Oracle

Flagstaff

*Marana

*Avra Water Cooperative

Apache Junction

*Metro Water District - Summer

*Metro Water District - Winter

*Oro Valley

Scottsdale

*Tucson

Mesa

*Community WC of Green Valley

Ray Water Company

Nogales

Phoenix - Summer

Phoenix - Winter

*Flowing Wells Irrigation District

Yuma

Dollars

10,000 gallons/month

25,000 gallons/month

Monthly base charge plus commodity charges. Excludes taxes, surcharges, sewerage charges, etc.* Denotes Tucson area water providers.

NATIONAL PRIMARY DRINKING WATER STANDARDSNational Primary Drinking Water Regulations (NPDWRs or primary standards) are legally enforceable standards that apply to public water systems. Primarystandards protect drinking water quality by limiting the levels of specific contaminants that can adversely affect public health and are known or anticipated tooccur in public water systems.

MCLG1 MCL2 OR TT3 POTENTIAL HEALTH EFFECTS SOURCES OF CONTAMINANTS(MG/L)4 (MG/L)4

INORGANIC CHEMICALS

Antimony 0.006 0.006 Increase in blood cholesterol; decrease Discharge from petroleum refineries;in blood glucose fire retardants; ceramics; electronics; solder

Arsenic none5 0.05 Skin damage; circulatory system Discharge from semiconductor manufacturing;problems; increased risk of cancer petroleum refining; wood preservatives; animal

feed additives; herbicides; erosion of naturaldeposits

Asbestos 7 million 7 MFL Increased risk of developing benign Decay of asbestos cement in water mains;(fiber >10 micrometers) intestinal polyps erosion of natural depositsfibers per Liter

Barium 2 2 Increase in blood pressure Discharge of drilling wastes; discharge frommetal refineries; erosion of natural deposits

Beryllium 0.004 0.004 Intestinal lesions Discharge from metal refineries andcoal-burning factories; discharge from electrical,aerospace, and defense industries

Cadmium 0.005 0.005 Kidney damage Corrosion of galvanized pipes; erosion ofnatural deposits; discharge from metalrefineries; runoff from waste batteries andpaints

Chromium (total) 0.1 0.1 Some people who use water containing Discharge from steel and pulp mills;chromium well in excess of the MCL erosion of natural depositsover many years could experience allergicdermatitis

Copper 1.3Action Level=1.3; TT6 Short term exposure: Gastrointestinal Corrosion of household plumbing systems;distress. erosion of natural deposits; leaching from woodLong term exposure: Liver or kidney preservativesdamage. Those with Wilson’s Diseaseshould consult their personal doctor iftheir water systems exceed the copperaction level.

Cyanide (as free cyanide) 0.2 0.2 Nerve damage or thyroid problems Discharge from steel/metal factories; dischargefrom plastic and fertilizer factories


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Fluoride 4.0 4.0 Bone disease (pain and tenderness of the Water additive which promotes strong teeth;bones); Children may get mottled teeth. erosion of natural deposits; discharge from

fertilizer and aluminum factories

Lead zero Action TT6 Infants and children: Delays in physical or Corrosion of household plumbing systems;Level=0.015 mental development. erosion of natural deposits

Adults: Kidney problems; high bloodpressure

Inorganic Mercury 0.002 0.002 Kidney damage Erosion of natural deposits; discharge fromrefineries and factories; runoff from landfills andcropland

Nitrate (measured as 10 10 “Blue baby syndrome” in infants under six Runoff from fertilizer use; leaching fromNitrogen) months - life threatening without septic tanks, sewage; erosion of natural deposits

immediate medical attention.Symptoms: Infant looks blue and hasshortness of breath.

Nitrite (measured as 1 1 “Blue baby syndrome” in infants under six Runoff from fertilizer use; leaching frommonths - life threatening without septic tanks, sewage; erosion of natural deposits

Nitrogen) immediate medical attention.Symptoms: Infant looks blue and hasshortness of breath.

Selenium 0.05 0.05 Hair or fingernail loss; numbness in Discharge from petroleum refineries; erosion offingers or toes; circulatory problems natural deposits; discharge from mines;

Thallium 0.0005 0.002 Hair loss; changes in blood; kidney, Leaching from ore-processing sites; dischargeintestine, or liver problems from electronics, glass, and pharmaceutical

companies

ORGANIC CHEMICALS

Acrylamide zero TT7 Nervous system or blood problems; Added to water during sewage/wastewaterincreased risk of cancer treatment

Alachlor zero 0.002 Eye, liver, kidney or spleen problems; Runoff from herbicide used on row cropsanemia; increased risk of cancer

Atrazine 0.003 0.003 Cardiovascular system problems; Runoff from herbicide used on row cropsreproductive difficulties

Benzene zero 0.005 Anemia; decrease in blood platelets; Discharge from factories; leaching gas storageincreased risk of from cancer tanks and landfills

Benzo(a)pyrene zero 0.0002 Reproductive difficulties; Leaching from linings of water storage tanksincreased risk of cancer and distribution lines


131


Carbofuran 0.04 0.04 Problems with blood or nervous system; Leaching of soil fumigant used on rice and alfalfareproductive difficulties.

Carbon tetrachloride zero .005 Liver problems; increased risk of Discharge from chemical plants and othercancer industrial activities

Chlordane zero 0.002 Liver or nervous; Residue of banned industrial other industrialincreased risk of cancer termiticide

Chlorobenzene 0.1 0.1 Liver or kidney problems Discharge from chemical and agriculturalchemical factories

2,4-D 0.07 0.07 Kidney, liver, or adrenal gland Runoff from herbicide used on row cropsproblems

Dalapon 0.2 0.2 Minor kidney changes Runoff from herbicide used on rights of way

1,2-Dibromo-3-chloropropane zero 0.0002 Reproductive difficulties; Runoff/leaching from (DBCP) soil fumigant usedincreased risk of canceron soybeans, cotton, pineapples, and orchards

o-Dichlorobenzene 0.60.6 Liver, kidney, or circulatory system Discharge from industrial chemical factoriesproblems

p-Dichlorobenzene 0.075 0.075 Anemia; liver, kidney or spleen damage; Discharge from industrial chemical factorieschanges in blood

1,2-Dichloroethane zero 0.005 Increased risk of cancer Discharge from industrial chemical factories

1-1-Dichloroethylene 0.007 0.007 Liver problems Discharge from industrial chemical factories

cis-1, 2-Dichloroethylene 0.07 0.07 Liver problems Discharge from industrial chemical factories

trans-1,2-Dichloroethylene0.1 0.1 Liver problems Discharge from industrial chemical factories

Dichloromethane zero 0.005 Liver problems; cancer Discharge from increased risk of pharmaceuticaland chemical factories

1-2-Dichloropropanezero 0.005 Increased risk of cancer Discharge from industrial chemical factories

Di(2-ethylhexyl)adipate 0.40.4 General toxic effects or reproductive Leaching from PVC plumbing systems; dischargedifficulties

from chemical factories

Di(2-ethylhexyl)phthalate zero 0.006 Reproductive difficulties; liver Discharge from rubber and chemical factoriesproblems; increased risk of cancer

Dinoseb 0.007 0.007 Reproductive difficulties Runoff from herbicide used on soybeans andvegetables


132


Dioxin (2,3,7,8-TCDD) zero 0.00000003 Reproductive difficulties; Emissions from waste incineration and otherincreased risk of cancer combustion; discharge from chemical factories

Diquat 0.02 0.02 Cataracts Runoff from herbicide use

Endothall 0.1 0.1 Stomach and intestinal problems Runoff from herbicide use

Endrin 0.002 0.002 Nervous system effects Residue of banned insecticide

Epichlorohydrin zero TT7 Stomach problems; reproductive Discharge from industrial chemical factories;difficulties; increased risk of cancer added to water during treatment process

Ethylbenzene 0.7 0.7 Liver or kidney problems Discharge from petroleum refineries

Ethelyne dibromide zero 0.00005 Stomach problems; reproductive Discharge from petroleum refineriesdifficulties; increased risk of cancer

Glyphosate 0.7 0.7 Kidney problems; reproductive difficulties Runoff from herbicide use

Heptachlor zero 0.0004 Liver damage; increased risk of cancer Residue of banned termiticide

Heptachlor epoxide zero 0.0002 Liver damage; increased risk of cancer Breakdown of hepatachlor

Hexachlorobenzene zero 0.001 Liver or kidney problems; reproductive Discharge from metal refineries and agriculturaldifficulties; increased risk of cancer chemical factories

Hexachlorocyclopentadiene 0.05 0.05 Kidney or stomach problems Discharge from chemical factories

Lindane 0.0002 0.0002 Liver or kidney problems Runoff/leaching from insecticide used oncattle, lumber, gardens

Methoxychlor 0.04 0.04 Reproductive difficulties Runoff/leaching from insecticide used on fruits,vegetables, alfalfa, livestock

Oxamyl (Vydate) 0.2 0.2 Slight nervous system effects Runoff/leaching from insecticide used on apples,potatoes, and tomatoes

Polychlorinated biphenyls zero 0.0005 S Skin changes; thymus gland problems; Runoff from landfills; discharge of waste(PCBs) immune deficiencies; reproductive or chemical

nervous system difficulties;increased risk of cancer

Pentachlorophenol zero 0.001 Liver or kidney problems; Discharge from woodpreserving factoriesincreased risk of cancer

Picloram 0.5 0.5 Liver problems Herbicide runoff

Simazine 0.004 0.004 Problems with blood Herbicide runoff


133


Styrene 0.1 0.1 Liver, kidney, and circulatory problems Discharge from rubber and plastic factories;leaching from landfills

Tetrachloroethylene zero 0.005 Liver problems; increased risk of Leaching from PVC pipes; discharge fromcancer factories and dry cleaners

Toluene 1 1 Nervous system, kidney, or liver Discharge from petroleum factoriesproblems

Total Trihalomethanes none5 0.10 Liver, kidney or central nervous Byproduct of drinking water disinfection(TTHMs) system problems; increased risk of cancer

Toxaphene zero 0.003 Kidney, liver, or thyroid problems; Runoff/leaching from insecticide used onincreased risk of cancer cotton and cattle

2,4,5-TP (Silvex) 0.05 0.05 Liver problems Residue of banned herbicide

1,2,4-Trichlorobenzene 0.07 0.07 Changes in adrenal glands Discharge from textile finishing factories

1,1,1-Trichloroethane 0.2 0.20 Liver, nervous system, or Discharge from metal degreasing sites andcirculatory problems other factories

1,1,2-Trichloroethane 0.003 0.005 Liver, kidney, or immune system problems Discharge from industrial chemical factories

Trichloroethylene zero 0.005 Liver problems; increased risk of cancer Discharge from petroleum refineries

Vinyl chloride zero 0.002 Increased risk of cancer Leaching from PVC pipes; discharge from plasticfactories

Xylenes (total) 10 10 Nervous system damage Discharge from petroleum factories; dischargefrom chemical factories

Beta particles and photon none5 4 millirems Increased risk of cancer Decay of natural and man-made depositsper year

Gross alpha particle activity none5 15 picocuries Increased risk of cancerper Liter (pCi/L) Erosion of natural deposits

Radium 226 and Radium 228 none5 5 pCi/L Increased risk of cancerErosion of natural deposits

MICROORGANISMS

Giardia lamblia zero TT8 Giardiasis, a gastroenteric disease Human and animal fecal waste


134


Heterotrophic plate count N/A TT8 HPC has no health effects, but canindicate how effective treatment is atcontrolling microorganisms.

Legionella zero TT8 Legionnaire’s Disease, commonly Found naturally in water; multiplies in heatingknown as pneumonia systems

Total Coliforms (including zero 5.0%9 Used as an indicator that otherfecal coliform and E. Coli) potentially harmful bacteria may be present10

Human and animal fecal waste

Turbidity N/A TT8 Turbidity has no health effects but Soil runoffcan interfere with disinfection and providea medium for microbial growth. It mayindicate the presence of microbes.

Viruses (enteric) zero TT8 Gastroenteric disease Human and animal fecal waste

National Secondary Drinking Water RegulationsNational Secondary Drinking Water Regulations (NSDWRs or secondary standards) are non-enforceable guidelines regulating contaminants that may causecosmetic effects (such as skin or tooth discoloration) or aesthetic effects (such as taste, odor, or color) in drinking water. EPA recommends secondary standards towater systems but does not require systems to comply. However, states may choose to adopt them as enforceable standards.


135

Contaminant Secondary StandardAluminum 0.05 to 0.2 mg/LChloride 250 mg/LColor 15 (color units)Copper 1.0 mg/LCorrosivity noncorrosiveFluoride 2.0 mg/LFoaming Agents 0.5 mg/L

Contaminant Secondary StandardIron 0.3 mg/L

Manganese 0.05 mg/LOdor 3 threshold odor number

PH 6.5-8.5Silver 0.10 mg/L

Sulfate 250 mg/LTotal Dissolved Solids 500 mg/L

Zinc 5 mg/L

NOTES

1 Maximum Contaminant Level Goal (MCLG) - The maximum level of a contaminant in drinking water at which no known or anticipated adverse effect on thehealth effect of persons would occur, and which allows for an adequate margin of safety. MCLGs are non-enforceable public health goals.

2 Maximum Contaminant Level (MCL) - The maximum permissible level of a contaminant in water which is delivered to any user of a public water system. MCLsare enforceable standards. The margins of safety in MCLGs ensure that exceeding the MCL slightly does not pose significant risk to public health.

3 Treatment Technique - An enforceable procedure or level of technical performance which public water systems must follow to ensure control of a contaminant.

4 Units are in milligrams per Liter (mg/L) unless otherwise noted.

5 MCLGs were not established before the 1986 Amendments to the Safe Drinking Water Act. Therefore, there is no MCLG for this contaminant.

6 Lead and copper are regulated in a Treatment Technique which requires systems to take tap water samples at sites with lead pipes or copper pipes that have leadsolder and/or are served by lead service lines. The action level, which triggers water systems into taking treatment steps if exceeded in more than 10% of tap watersamples, for copper is 1.3 mg/L, and for lead is 0.015mg/L.

7 Each water system must certify, in writing, to the state (using third-party or manufacturer’s certification) that when acrylamide and epichlorohydrin are used indrinking water systems, the combination (or product) of dose and monomer level does not exceed the levels specified, as follows: Acrylamide = 0.05% dosed at 1mg/L (or equivalent)* Epichlorohydrin = 0.01% dosed at 20 mg/L (or equivalent).

8 The Surface Water Treatment Rule requires systems using surface water or groundwater under the direct influence of surface water to (1) disinfect their water, and(2) filter their water to meet criteria for avoiding filtration so that the following contaminants are controlled at the following levels: * Giardia lamblia: 99.9%killed/inactivated Viruses: 99.99% killed/inactivated; * Legionella: No limit, but EPA believes that if Giardia and viruses are inactivated, Legionella will also becontrolled; * Turbidity: At no time can turbidity (cloudiness of water) go above 5 nephelolometric turbidity units (NTU); systems that filter must ensure that theturbidity goes no higher than 1 NTU (0.5 NTU for conventional or direct filtration) in at least 95% of the daily samples for any two consecutive months; * HPC:NO more than 500 bacterial colonies per milliliter.

9 No more than 5.0% samples total coliform-positive in a month. (For water systems that collect fewer than 40 routine samples per month, no more than onesample can be total coliform-positive). Every sample that has total coliforms must be analyzed for fecal coliforms. There cannot be any fecal coliforms.

10 Fecal coliform and E. coli are bacteria whose presence indicates that the water may be contaminated with human animal wastes. Microbes in these wastes cancause diarrhea, cramps, nausea, headaches, or other symptoms.

Source: Environmental Protection Agency Web Site: www.epa.gov


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137

1999 WATER RATE SCHEDULE FOR THE CENTRAL ARIZONA PROJECT

Cost Component 1999 2000 2001 2002 2003

Municipal/Industrial Charges (1) $48/af $54/af $54/af $54/af $54/af

Agricultural Charges (2) 2/af 2/af 2/af 2/af 2/af

Water Delivery Costs:Fixed OM&R (3) 31/af Determined Annually

Pumping Energy (4) 38/af Determined Annually

Total 1999 Delivery Costs $69/af

Delivery Rates 1999 2000 2001 2002 2003

Municipal and Industrial (A) $69/af $70/af $72/af $73/af $75/af

Agricultural

Pool 1 (200,000 af) (B) 32/af 33/af 34/af 35/af 36/af

Pool 2 (200,000 af) (C) 22/af 23/af 24/af 25/af 26/af

Pool 3 (5,D) 45/af Determined Annually

M&I Incentive Recharge (6,E) 43/af

Federal (F) 69/af 70/af 72/af 73/af 75/af

AWBA (G) 43/af

Miscellaneous Uses (7, H) 43/af Determined Annually

Notes:1. Paid on full allocation regardless of water deliveries, not included in delivery rates.2. Paid on actual deliveries and included in delivery rates.3. $43.5 million fixed OM&R costs ÷ 1,416,000 af of projected deliveries = $31/af. This amount is collected on all ordered water whether delivered or not.4. $53.6 million pumping energy costs ÷ 1,416,000 af of projected deliveries = $38/af. This amount is collected only for water actually delivered.5. Rate is pumping energy component plus $5 contribution to fixed OM&R plus the $2 agriculture capital charge.6. Rate is pumping energy component plus $5 contribution towards fixed OM&R. See reverse side for rules regarding eligibility for and use of M&I incentive recharge water.7. Rate is pumping energy component plus $5 contribution towards fixed OM&R.A. M&I – The delivery rate for M&I subcontractors. For M&I users who are not subcontractors, we add the capital charge and create an Excess M&I contractor rate for “as available” water.B. Pool 1 – All agricultural entities who originally signed a subcontract.C. Pool 2 – Those agricultural entities that waived their subcontract rights in two-party agreements with CAWCD; CAWCD waived the agricultural take-or-pay requirements. Excluded those

agricultural entities that relinquished their subcontracts to others for the benefit of their district, i.e., Harquahala Valley Irrigation District, Roosevelt Water Conservation District, andHoHoKam Irrigation District.

D. Pool 3 – An agricultural customer who meets basic qualifications including those who want more than their allocated share of Pool 1 and Pool 2 water.E. M&I Incentive Recharge – A special program offered to M&I subcontractors only. They must have valid Arizona Department of Water Resources permits and must gain recharge/storage credits from

this activity. The Board has approved this program through 1999. CAP may participate with some agricultural entities in a limited fashion.F. Federal – For federal purposes (Indians, USBR construction water, etc.)G. AWBA – Water purchases by the Arizona Water Banking Authority. It is available for scheduling after all other schedules have been filled.H. Miscellaneous Uses– Water for recreational and fish and wildlife purposes.

CAP WATER SUBCONTRACT AMOUNTS IN THE TUCSON AMA

Entity Allocation (acre-feet)

City of Tucson 138,920

San Xavier District of Tohono O’odham Nation 27,000

State Land Department 14,000

Schuk Toak District of Tohono O’odham Nation 10,800

Metropolitan Domestic Water Improvement District 8,858

Flowing Wells Irrigation District 4,354

Spanish Trail Water Company 3,037

Town of Oro Valley 2,294

Green Valley Water Company 1,900

Midvale Farms 1,500

Community Water Company of Green Valley 1,337

Vail Water Company 786

Pascua Yaqui Tribe 500

Town of Marana 47


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THE PURPOSE OF THIS ARTICLE IS TO RESTORE FIRST CLASS DRINKING WATER TO THE PEOPLE OF TUCSON AND REPLENISH TUCSON’SGROUNDWATER SUPPLY BY AMENDING CHAPTER 27 OF THE TUCSON CODE AND ADDING A NEW ARTICLE VI PROVIDING FOR THE USE OFWATER RESOURCES.

Section 1. Chapter 27 of title Tucson code is amended by adding Artic1e VI to read:

ARTICLE VIWATER CONSUMER PROTECTION ACT

SECTION 27-90. METHOD1. THE CITY OF TUCSON SHALL USE ONLY GROUNDWATER FROM UNPOLLUTED SOURCES AS ITS POTABLE WATER SUPPLY FOR A FIVE

YEAR INTERIM PERIOD BEGINNING ON THE EFFECTIVE DATE OF THIS ARTICLE, EXCEPT AS SPECIFICALLY PROVIDED IN SECTION 27-91.2. THE CITY OF TUCSON SHALL TAKE THE NECESSARY ACTIONS TO ENSURE THAT IT IS IN TOTAL COMPLIANCE WITH ITS EXISTING

CONTRACT FOR CENTRAL ARIZONA PROTECT (CAP) WATER.3. FOR FIVE YEARS FROM THE EFFECTIVE DATE OF THIS ARTICLE, CAP WATER DELIVERED TO THE CITY OF TUCSON SHALL BE USED

ONLY FOR ONE OR MORE OF THE FOLLOWING PURPOSES;(a) FOR SELLING OR EXCHANGING WATER UNDER THE TERMS OF THE CITY’S EXISTING CAP SUBCONTRACT.(b) TO PRESERVE TUCSON’S GROUNDWATER FOR DOMESTIC USE BY REPLACING GROUNDWATER WHICH WOULD OTHERWISE HAVE

BEEN WITHDRAWN FOR USES OTHER THAN AS POTABLE WATER SUCH AS AGRICULTURE, MING AND OTHER INDUSTRY.(c) TO PREVENT LAND SUBSIDENCE AND AUGMENT TUCSON’S GROUNDWATER SUPPLY BY BASIN AND STREAM BED RECHARGE.(d) TO REPLACE OTHER WATER SUPPLIES CURRENTLY BEING EMPLOYED FOR INDUSTRIAL AND LANDSCAPE IRRIGATION USE

INCLUDING PARKS, GOLF COURSES AND SCHOOLS.(e) FOR DIRECT WELL INJECTION IF IT IS TREATED AS DESCRIBED IN SECTION 27-91 AND IS FREE FROM DISINFECTION BYPRODUCTS.SECTION 27-91. EXCEPTIONNOT WITHSTANDING ANY OTHER PROVISION OF THIS ARTICLE, CAP WATER MAY BE DIRECTLY DELIVERED AS A POTABLE WATER

SUPPLY ONLY IF IT IS TREATED IN A MANNER SUFFICIENT TO ENSURE THAT THE QUALITY OF THE DELIVERED WATER IS EQUAL TO ORBETTER IN SALINITY, HARDNESS AND DISSOLVED ORGANIC MATERIAL THAN THE QUALITY OF THE GROUNDWATER BEING DELIVEREDFROM TUCSON’S AVRA VALLEY WELL FIELD ON THE EFFECTIVE DATE OF THIS ARTICLE.

SECTION 27-92 RECHARGE.1. THE CITY OF TUCSON SHALL NOT RECHARGE WATER IN ANY AREA THAT CONTAINS OR IS ADVERSELY EFFECTED BY TOXIC

LANDFILLS.2. TO PREVENT LAND SUBSIDENCE WITHIN THE CITY OF TUCSON’S CENTRAL WELL FIELD, ALL GROUNDWATER WITHDRAWALS SHALL

BE COMPLETELY REPLENISHED, AS MEASURED OVER ANY FIVE YEAR PERIOD, USING RECHARGE INCLUDING RECHARGE OF CAP WATER ASPROVIDED IN SECTION 27-90. 3.(e).

SECTION 27-93.DEFINITIONSIN THIS ARTICLE, UNLESS THE CONTEXT OTHERWISE REQUIRES:1. “POLLUTION” MEANS THE PRESENCE OF AN AMOUNT OF ANY SUBSTANCE IN GROUNDWATER WHICH EXCEEDS ANY STANDARD

PRESCRIBED BY THE LAWS OF THE STATE OF ARIZONA OR THE UNITED STATES FOR POTABLE WATER.2. “DISINFECTION BYPRODUCTS” ARE THE CHEMICAL COMPOUNDS FORMED WHEN CHLORINE, OZONE OR CHLORAMINES ARE USED

TO DISINFECT WATER CONTAINING DISSOLVED ORGANIC MATERIAL.


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THE WATER CONSUMER PROTECTION ACT

Section 2.FIVE YEARS AFTER THE EFFECTIVE DATE OF THIS ORDINANCE,

THE MAYOR AND COUNCIL OF THE CITY OF TUCSON MAY, UPON AMAJORITY VOTE, SUBMIT TO THE REGISTERED VOTERS OF THE CITYFOR APPROVAL AT A CITY OF TUCSON GENERAL ELECTIONAPROPOS AL TO REPEAL OR MODIFY ARTICLE VI OF CHAPTER 27 OFTHE TUCSON CODE AS ADDED BY THIS ORDINANCE.

Section 3 SEVERABILITYIF A PROVISION OF THIS ORDINANCE OR ITS APPLICATION TO

ANY PERSON OR CIRCUMSTANCE IS HELD INVALID, THE INVALIDITYDOES NOT AFFECT OTHER PROVISIONS OR APPLICATIONS OF THEORDINANCE THAT CAN BE GIVEN EFFECT WITHOUT THE INVALIDPROVISION OR APPLICATION, AND TO THIS END THE PROVISIONSOF THIS ORDINANCE ARE SEVERABLE

Water in the Tucson Area: Seeking Sustainabiility

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GENERAL INFORMATIONAn overview of water issues in the Sonoran

Desert is found in Nancy Laney’s Desert Waters:From Ancient Aquifers to Modern Demands publishedby the Arizona Sonora Desert Museum in 1998. Ageneral introduction to water issues in Arizona canbe found in Ensuring Arizona’s Water Quantity andQuality Into the 21st Century, a background reportprepared by the University of Arizona for theSeventy-first Arizona Town Hall, October 26-29,1997. A Water Issues Primer for the Tucson ActiveManagement Area published by the SouthernArizona Water Resources Association (SAWARA) in1983 is a helpful, although somewhat outdatedgeneral introduction to the basics of water in theTucson area. SAWARA has published a series ofinformative newsletters on a variety of Tucson areawater topics, including recharge, CAP, constructedwetlands, water supplies and wastewater. These areavailable on a Web site. SAWARA also has a videopresenting an overview of Tucson’s water situation.

Where to Get Free (or Almost Free) Informationabout Water in Arizona (1998 edition) is a directoryof sources of water information, including Websites. Where to Find Water Expertise at ArizonaUniversities (1998 edition) is a directory of sources ofwater information at Arizona state universities.Both are by Barbara Tellman and are available freefrom the Water Resources Research Center(WRRC), The University of Arizona and are insearchable format at the WRRC Web site. This Website also contains water information as well as linksto water agencies.

Chapter 2: LOOKING TO THEPAST TO UNDERSTAND THEPRESENT

Much of the information about the history ofTucson Water came from Lynn Baker, unofficialTucson Water historian. Much of the informationabout the history of wastewater in Pima Countycame from John Schladweiler, unofficial PimaCounty Wastewater Management Departmenthistorian. A valuable source of information aboutthe history of water development and technology inPima County is a 1986 Master’s thesis (University ofArizona) by Doug Kupel titled Diversity ThroughAdversity: Tucson Basin Water Control Since 1854.C.L. Sonnichsen’s Tucson: The Life and Times of anAmerican City, published by the University ofOklahoma Press in 1982, is a detailed history ofTucson. The history of the Santa Cruz River isdiscussed in Arizona’s Changing Rivers: How PeopleHave Impacted the Rivers by Barbara Tellman,Richard Yarde and Mary Wallace, published by theWRRC, The University of Arizona in 1997. Moredetailed information is available in Arizona StreamNavigability Study for the Santa Cruz River, a reportby SFC Engineering and others for the ArizonaState Land Department in 1996. The history of theCentral Arizona Project was documented by RichJohnson in The Central Arizona Project, published bythe University of Arizona Press in 1977. Thehistory of opposition to the CAP was documentedby Frank Welsh in How to Create a Water Crisis,published by Johnson Books (Boulder) in 1985.

Chapter 3: IN SEARCH OFADEQUATE WATER SUPPLIES

General information about groundwater isavailable in a booklet from the American Instituteof Professional Geologists titled Ground Water Issuesand Answers, available from the Arizona GeologicalSurvey office in Tucson. Edward Davidson’sGeohydrology and Water Resources of the TucsonBasin, Arizona (USGS Water Supply Paper; 1939-E,1973) has a description of the basics of localgeohydrology.

Numerous government documents areavailable, some of which are listed below. Most ofthe local government documents and consultantreports done for local government are available inthe Tucson Public Library’s government referencesection in the downtown library.

Tucson Water’s Planning and TechnicalServices Division provides periodic reports on theaquifer and withdrawals, titled Annual GroundwaterWithdrawal and Use Report. Tucson Water alsoprovides an annual report, Annual Static Water LevelBasic Data Report: Tucson Basin and Avra Valley, PimaCounty, Arizona. Tucson Water published a usefulbooklet in 1998, Status of the Aquifer, in conjunctionwith the U.S. Geological Survey and the ArizonaDepartment of Water Resources. An example of aconsultant’s report with useful information is byMark Cross, Hydrogeologic Constraints on ContinuedGroundwater Withdrawals by the City of Tucson. (ErrolL. Montgomery and Associates, Inc. 1998). TucsonWater also produces long-term planning documentssuch as Tucson Water Resources Plan: 1990 to 2100.

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Appendix CAdditional Information

(Produced by CH2M Hill for Tucson Water. July 3,1989). and Tucson Water 50-Year Operating Plan:Planning Assessment Report. (Malcolm Pirnie, Inc.February 1994).

CAP, GeneralAn overview of the CAP is available in the

Arizona Department of Water Resources’Governor’s Central Arizona Project AdvisoryCommittee’s report (prepared with assistance of theCentral Arizona Water Conservation District andthe U.S. Bureau of Reclamation), Description of theCentral Arizona Project. (April 1993). The CentralArizona Water Conservation District has severalbrochures, maps and informative materials aboutCAP. The fall-winter 1993 WRRC. Arroyo,“Long-Awaited CAP Water Delivers Troubled Waterto State” also provides information. Analysis of thepossibility of extending the CAP canal to the GreenValley area can be found in Malcolm Pirnie, Inc., inassociation with Errol Montgomery and Associates,Inc., Sahuarita-Green Valley Area Central ArizonaProject Water Use Feasibility Analysis and DeliverySystem Optimization Study, prepared for ArizonaDepartment of Water Resources, TAMA, September1998.

RechargeA discussion of issues related to recharge in the

Tucson area and an assessment of current andpotential projects using CAP water can be found inthe Regional Recharge Plan, written by theInstitutional Policy and Advisory Group as part ofthe Regional Recharge Planning Process coordinatedby the Tucson AMA of the Arizona Department ofWater Resources (Institutional Policy and AdvisoryGroup, 1998). This planning process began with thetechnical and background work completed by theRegional Recharge Committee, Technical Report,Arizona Department of Water Resources TucsonActive Management Area, September 1996.

A series of biennial symposia on recharge havebeen held over the years and contain much usefulinformation. Copies of the proceedings for pastyears are available from WRRC. Another

conference document is Proceedings of the Symposiumon Effluent Use Management, edited by Kenneth D.Schmidt and Mary G. Wallace (AWRA 29th AnnualConference August 29 - September 2, 1993).

Some other sources of information on rechargemethods and recharge policy in the Tucson areainclude:

CH2M Hill. Rillito Recharge Project: AnEvaluation of Recharge Techniques. Prepared for theArizona Department of Water Resources inCooperation With Tucson Water and Pima CountyFlood Control District, July 1992. Tucson waterissued a series of reports on City of Tucson SweetwaterUnderground Storage and Recovery Facility in 1991 and1994. These are just a few of the many governmentdocuments on related topics.

Some theses and dissertations have provideduseful information. A complete list of those fromthe University of Arizona’s Hydrology and Water

Resources Department is available on the Web site.Keith, S.J., Stream Channel Recharge in the TucsonBasin and Its Implications for GroundwaterManagement. The University of Arizona,Department of Hydrology and Water Resources.M.S. Thesis, 1980.

An analysis of the impacts of the WaterConsumer Protection Act can be found in a paperby L.G. Wilson, W.G. Matlock and K.L. Jacobs,Hydrologic Uncertainties and Policy Implications: TheWater Consumer Protection Act of Tucson, Arizona,USA. Hydrogeology Journal. Vol. 6, pp. 3-14. 1998.

SubsidenceA good general introduction to subsidence is in

Steven Slaff’s Land Subsidence and Earth Fissures InArizona published by the Arizona Geological Survey,Down-to-Earth Series 3 in 1993. Another general


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WEB SITES WITH WATER INFORMATION

Arizona Department of Environmental Quality — www.adeq.state.az.usArizona Department of Water Resources — www.adwr.state.az.usArizona Geological Survey — www.azgs.state.az.usArizona Water Banking Authority — www.awba.state.az.usCentral Arizona Project and Central Arizona Groundwater Replenishment District —

www.cap.az.usCooperative Extension, The University of Arizona — ag.arizona.edu/extensionDepartment of Hydrology and Water Resources, The University of Arizona —

www.hwr.arizona.eduMetropolitan Domestic Water Improvement District — www.metrowater.com/Oro Valley Water Utility — www.ci.oro-valley.az.us/dpw/water_utility_.htmPima County Department of Environmental Quality — www.deq.co.pima.az.usPima County Flood Control District — sss.dot.co.pima.az.us/floodSouthern Arizona Water Resources Association — www.scottnet.com/sawara/Tucson Regional Water Council — www.azstarnet.com/~trwc/Tucson Water — www.ci.tucson.az.us/waterU.S. Bureau of Reclamation — www.usbr.govU.S. Environmental Protection Agency — www.epa.govU.S. Geological Survey — www.daztcn.wr.usgs.gov/Water Resources Research Center, The University of Arizona — ag.arizona.edu/AZWATER/WaterWiser - www.waterwiser.org

introduction can be found in the Arroyo publishedby the WRRC in Summer 1992 titled “LandSubsidence, Earth Fissures Are Changing Arizona’sLandscape.”

The following more technical studies werepublished by the U.S.G.S.:

Anderson, S.R. Potential for Aquifer Compaction,Land Subsidence, and Earth Fissures in the Tucson Basin,Pima County, Arizona. U.S. Geological SurveyHydrologic Investigations Atlas HA-713. 1988.

Hanson, R.T. Aquifer-System Compaction, TucsonBasin and Avra Valley, Arizona: U.S. GeologicalSurvey Water Resources Investigations Report88-4172. 1989.

Hanson, R.T., S.R. Anderson and D.R. Pool.Simulation of Ground-Water Flow and Potential LandSubsidence, Avra Valley, Arizona. U.S. GeologicalSurvey. Water Resource Investigations Report. 1990.

Hanson, R.T. and J.F. Benedict. Simulation ofGround-Water Flow and Potential Land Subsidence,Upper Santa Cruz Basin, Arizona. U.S. GeologicalSurvey. Water Resources Investigations Report93-4196. 1994.

Frisch-Gleason, Robin, Steven Slaff and RichardA.Trapp. Bibliography of Subsidence and Earth FissuresWithin Arizona. Arizona Geological Survey OpenFile Report 95-8. June 1995.

Hoffman, John P., Donald R. Pool, A.D.Konieczki and Michael C. Carpenter. Investigation ofthe Causes of Sinks in the San Xavier District, TohonoO’odham Nation, Pima County, Arizona. U.S.Geological Survey, Open File Report 97-19. 1997.

Schumann, Herbert H. and S.R. Anderson.Land Subsidence Measurements and Aquifer-CompactionMonitoring in Tucson Basin and Avra Valley, Arizona.U.S. Geological Survey. Water ResourcesInvestigations Report 88-4167. December 1998.

EffluentThe Winter 1997 issue of SAWARA’s

Waterwords, Wastewater, A Growing Resource? andthe Summer 1990 issue, Special Issue on Effluent As AWater Supply provide much valuable information.

Information on the supply-related aspects ofeffluent can be found in:

Galyean, Kenneth C. Infiltration of WastewaterEffluent in the Santa Cruz River Channel, Pima County,Arizona. Water Resources Investigations Reports;96-4021, 1996.

Pima County Wastewater ManagementDepartment’s Tucson Water. Regional EffluentUtilization Plan. Phase A: Preliminary Regional EffluentUtilization Study. Malcolm Pirnie, Inc. February1991 and a final report in 1995.

Grey Wilson and others studied the waterquality impacts of effluent recharge in Water QualityChanges During Soil Aquifer Treatment of TertiaryEffluent. Water Resources Research, Vol. 67, No. 3,pp. 371-376. 1995.

Alternative SuppliesInformation about alternative water supply and

conservation strategies can be found in several issuesof Arroyo, a periodical series published by theWRRC, The University of Arizona. The spring1992 issue, “Weather Modification, a WaterResource Strategy to be Researched, Tested BeforeTried,” the August, 1998 issue, “ManagingWatersheds to Improve Land and Water”.

Chapter 4: COPING WITHFLOODWATER

An historical, if somewhat dated summary offlooding issues and information in Pima Countycan be found in Flooding and Erosion Hazards inTucson, published by Southwest EnvironmentalService in 1980. This is out of print, but availablein libraries. Two issues of WRRC’s Arroyo dealtwith general urban wash and flooding issues.“Often Neglected, Urban Washes Now Seen asAttractive Resource” (June 1991) and “FloodHazards, a Concern in Desert Areas of Arizona”(June l990).

Numerous reports from the Pima CountyFlood Control District and the City of Tucson dealwith specific flood-related issues. There are reportsfor each major watercourse in connection withproposed projects. Flood Control Concept Report forthe Lower Santa Cruz River, for example, by the Pima

County Department of Transportation and FloodControl District (July 1987) looks at alternativeflood control measures in the Marana area. Thereare also reports for the non-structural flood controlprojects, such as the Cienega Creek Preserve.Reports dealing with streambed recharge projects arealso available from the same sources. FEMAfloodplain maps may be viewed at the flood controldistricts.

Floodwater and RechargeGuzman, A.G., L.G. Wilson, S.P. Neuman and

M.D. Osborn. Simulating Effect of Channel Changes onStream Infiltration. Journal of HydraulicEngineering. American Society of Civil Engineers,Vol. 115, No. 12, pp. 1631-1645. 1989.

The Regional Recharge Committee issued aninformative Technical Report printed by theArizona Department of Water Resources TucsonActive Management Area in September 1996.

Chapter 5: THE MANYUSES OF WATER

Water UseMuch of the information on water use comes

from the Arizona Department of Water Resources’Tucson Active Management Area Draft ThirdManagement Plan 2000-2010 (1998) and from thefirst and second management plans. Also see theArizona Department of Water Resources’ TucsonActive Management Area 1996 report, State of theAMA.

Water ConservationEvery major water provider in the area has

information for its customers on water conservationtechniques. Water CASA and SAWARA alsoprovide such information.

General studies of water conservation includeB. Dziegielewski’s Evaluating Urban WaterConservation Programs: A Procedures Manual, prepared

Appendix C. Additional Information

143

for California Urban Water Agencies by Planningand Management Consultants, Ltd. February 1992.

A study of the impact of water rates onconservation is in Ari Michelsen and others’Effectiveness of Residential Water Conservation Price andNonprice Programs published by the ResearchFoundation of the American Water WorksAssociation, Denver, 1998.

Residential lawns in Tucson were studied byDavid Mouat and Michael Parton, Assessing theImpact of Tucson Peak Water Demand ReductionEffort on Residential Lawn Use, 1976-79. Office ofArid Lands, University of Arizona, December 1979.

Martin Karpiscak and others discussedconservation in Residential Water Conservation: Casadel Agua. Water Resources Bulletin. Vol. 26. No. 6,December 1990. pp. 939-948.

Residential Water Demand: A Micro Analysis UsingSurvey Data. by Gary Woodard and ToddRasmussen, (Hydrology and Water Resources inArizona and the Southwest, 14, 1984) examinesfactors that influence conservation.

Other surveys of municipal water use include:and in Tucson Water’s Results from the Fall 1992Residential Household Survey. (Draft.1995) and Craft,Marti, “Draft Summary of Landscape SurveyResults, for ADWR, TAMA, unpublished.

Water Harvesting,Xeriscape and Reuse

Harvesting Rainwater for Landscape Use, byPatricia Waterfall (University of ArizonaCooperative Extension and the Tucson ActiveManagement Area. Sept. 1998) provides practical,how-to information for homeowners. Pima CountyCooperative Extension has a variety of pamphletsdealing with xeriscaping and low water use plants.See their Web site. The Summer 1993 issue ofWRRC’s Arroyo “ Home Use of Graywater,Rainwater Conserves Water and May Save Money”provides a good overview. The water quality aspectsare discussed in Charles Gerba and others’ WaterQuality Study of Graywater Treatment Systems (WaterResources Bulletin. Vol. 31, No. 1, pp.109-116). Anexamination of large scale reuse can be found innumerous reports prepared for Tucson Water. One

example is Tucson Metropolitan Wastewater ReuseAssessment Update. (Malcolm Pirnie, Inc. August1994).

Riparian Water UseInformation about water use for local riparian

and wetlands came from the City of TucsonMultiple Benefit Project and Pima County FloodControl District. Both agencies have brochures forthe public describing various planned andcompleted projects. Riparian preservation andrestoration issues were described in two issues of theArroyo. The City of Tucson also has informationon the Sweetwater Wetland. The December 1988issue of Arroyo “Flow of Rivers and StreamsProvides Rich Benefits, Raises Varied Concerns” andthe Spring, 1993 issue “Managing the Flow to BetterUse, Preserve Arizona’s Rivers” discuss water forriparian areas. Information about the legal aspectsof effluent use in riparian areas came from BarbaraTellman’s Arizona’s Effluent Dominated RiparianAreas: Issues and Opportunities. (WRRC, Issue PaperNo. 12, 1992).

AgricultureStudies concerning agriculture include Paul

Wilson’s An Economic Assessment of Central ArizonaProject Agriculture, Department of Agricultural andResource Economics, University of Arizona, AReport Submitted to the Office of the Governorand the Arizona Department of Water Resources,1992; Arizona Academy, Tenth Arizona Town Hall,Do Agricultural Problems Threaten Arizona’s TotalEconomy? April, 1967. Some statistical informationon agriculture can be found in Arizona AgriculturalStatistics Service. Arizona Agricultural Statistics.USDA, Phoenix.

Some theses and dissertations on Arizonaagriculture include Esher, Joseph C., The EconomicSustainability of Central Arizona Project Agriculture.M.S. Thesis, Department of Agricultural andResource Economics, 1994. Peacock, Bruce,Complying With the Arizona Groundwater ManagementAct: Policy Implications, PhD Dissertation,Department of Agricultural and Resource

Economics, University of Arizona. 1994; and MarkEvans, An Assessment of the Impact of the ArizonaGroundwater Management Act in the Phoenix ActiveManagement Area. M.S. Thesis. Department ofAgricultural and Resource Economics.

Metal MiningSome useful information on metal mining in

the Tucson area can be found in SouthwestGroundwater Consultants, Inc., Conservation andCAP Use Potential of Tucson AMA Mines, Prepared forArizona Department of Water Resources, TAMA,1997. Pima Association of Governments,Groundwater Monitoring in the Tucson Copper MiningDistrict - Detailed Upper Santa Cruz Basin Mines TaskForce Area Recommendations, July 1983. ArizonaDepartment of Mines and Mineral Resources,Arizona’s Mining Update, 1998.

Chapter 6: ENSURING SAFEDRINKING WATER

Information about water quality in Arizona isavailable from the EPA Web site. ADEQ also has aWeb site with Arizona information. ADEQ’sbiennial reports (published in even-numbered years)on water quality in Arizona contain valuableinformation about surface and groundwater quality,including contamination sites of special concern.See Arizona Department of Environmental Quality.Arizona Water Quality Assessment 1996. The USGS iscollecting a large amount of water qualityinformation under its NAWQA Project (NationalWater Quality Assessment) some of which isavailable from the Tucson office. Pima County,City of Tucson, Dames and Moore. A summary ofthe TCE cleanup project is in TARP In-ChannelRecharge Pilot Proposal, Abbreviated Report (PimaCounty, City of Tucson and Dames and Moore.January 1997).

Water QualitySome general introductions to water quality

issues can be found in several issues of the WRRC


144

Arroyo by Joe Gelt. These include”Water Quality, aComplex Issue” (Summer 1987), “Nonpoint SourcePollution: Unfinished Business on the WaterQuality Agenda” (April 1990), “ConstructedWetlands: Using Human Ingenuity, NaturalProcesses to Treat Water, Build Habitat,” (March,1997) and “Microbes Increasingly Viewed as WaterQuality Threat” (March, 1998).

The Pima Association of Governments haspublished a series of reports on regional waterquality matters. Topics include A Regional Plan forWater, Sewerage and Solid Waste Management; AnAssessment of Groundwater Quality Near the SahuaritaLandfills, Sahuarita, Arizona; Phase I Report. Final,Avra Valley Recharge Project Stable Isotope StudyYear-End Progress Report Fiscal Year 1996-1997; CAPWater Salinity Impacts on Water Resources of the TucsonBasin; Central Avra Valley Storage and Recovery ProjectPilot Phase and Expanded Pilot Phase Stable IsotopeStudy; Fiscal Year 1997-1998 Progress Report;Groundwater Monitoring in the Tucson Copper MiningDistrict - Detailed Upper Santa Cruz Basin Mines TaskForce Area Recommendations; Landfills Along the SantaCruz River in Tucson and Avra Valley; Arizona and theWater Quality State of the Region Report.

Public attitudes toward CAP water weresurveyed by Gary Woodard and other in Impacts ofChanges in Water Quality and Consumer Responses inTucson, Arizona. (WRRC 1993). Malcolm PirnieEnvironmental Engineers looked at another similarcommunity’s experience with a change in watersource in Investigation of Potable Water Complaints inDickinson, Texas (Malcolm Pirnie, Inc., Special StudyReport, May, 1986).

Water TreatmentDames and Moore produced a series of papers

for Tucson Water on CAP Use Study for QualityWater in 1994 and 1995.

CorrosivityA study was done for Tucson Water by M.

McGuire and others, Review of Corrosion-RelatedWater Quality Problems in the City of Tucson (McGuireEnvironmental Consultants 30 September, 1993).

More general discussions of corrosivity are byR. Lane, Control of Scale and Corrosion in BuildingWater Systems (McGraw Hill, New York, 1993) and I.Wagner, Internal Corrosion in DomesticDrinking-Water Installations. Aqua, 41(4), 219-223,1992. The effects of corrosion on steel were studiedby R.J. Pisigan and J. Singley, Effects of Water QualityParameters on the Corrosion of Galvanized Steel(Journal American Water Works Association, 76-82,November, 1985).

Disinfection and Disinfection ByproductsThese are just a few of many studies of

disinfection treatment methods and disinfectionbyproducts. White, G., The Handbook ofChlorination, Van Nostrand Reinhold Company,New York; McGuire, M., S. Reiber, R. Sierka, J.Singley, and C. Steelink, Disinfectants for DrinkingWater Treatment— A White Paper (Prepared forTucson Water by Central Arizona Project WaterQuality Expert Panel), 25 April, 1995.

Disinfection byproducts are discussed in R.J.Bull’s Toxicology of Drinking Water Disinfection,(Washington State University, Pullman, WA); G.Cline and J. Russell’s An Evaluation of TreatmentStrategies for the Control of Disinfection By-Products:Water Quality vs. Cost and W.H. Glaze’s ReactionProducts of Ozone: A Review. Environmental HealthPerspectives, 69, 151-157, 1986. A great deal ofinformation on this subject is available from theEPA Web site.

SalinityStudies of salinity in the Colorado River

include the Colorado River Basin Salinity ControlForum’s Water Quality Standards for Salinity, ColoradoRiver System, 1993; the U.S. Department of theInterior’s Quality of Water - Colorado River Basin(Progress Report No. 18, 1997); and T.G. Miller andothers The Salty Colorado, The ConservationFoundation, Washington D.C., 1986.

The impacts of salinity are examined in Garrett,Charles K. Long Range Salinity Impacts in the TucsonBasin (Prepared for Tucson Water. December 1992);Kleinman, A. and F. Brown, Colorado River Salinity:Economic Impacts on Agricultural, Municipal and

Industrial Users (U.S. Department of Interior,Denver, 1980); Lohman, L., et al., Estimating theEconomic Impacts of Salinity of the Colorado River(prepared for the U.S. Bureau of Reclamation. FinalReport, 1988); R. d’Arge and L. Eubanks, Municipaland Industrial Consequences of Salinity in the ColoradoRiver Service Area of California, Salinity ManagementOptions for the Colorado River, 1978; G.C. Ragan andothers, Improved Estimates of Economic Damages fromResidential Use of Mineralized Water (CompletionReport No. 183 Colorado Water Resources ResearchInstitute, Colorado State University, August, 1993);Black and Veatch Consulting Engineers, EconomicEffects of Mineral Content in Municipal Water Supplies(Research and Development Progress Report No.260, U.S. Department of Interior, Office of SalineWater, 1967); the California Department of WaterResources, Consumer Costs of Water Quality inDomestic Water Use — Lompoc Area, Los Angeles, 1978;and Farnham, D., Water Quality: Its Effects onOrnamental Plants (Leaflet 2995), University ofCalifornia Cooperative Extension, 1985.

Treating water to reduce salinity is discussed inThompson, M., M.R. Wiesner, G. P. Westerhoff andM. P. Robinson, Manual on Membrane Processes forDrinking Water Treatment, Malcolm Pirnie TechnicalPublication, November, 1991 and in M.S. McGuireand others Membrane Processing of Surface and GroundWaters for Human Consumption (by Central ArizonaProject Water Quality Expert Panel), 16 January,1995.

TasteThe following are just a few of many studies of

taste in water. Bruvold, W., H. Ongerth and R.Dillehay, Consumer Assessment of Mineral Taste inDomestic Water. Journal American Water WorksAssociation, 575-580, November, 1969 and Bruvold,W., and J. Daniels, Standards for Mineral Content inDrinking Water. Journal AWWA, February, 1990.

Home water treatment alternatives are discussedin WRRC Arroyo, “Consumers Increasingly UseBottled Water, Home Water Treatment Systems toAvoid Direct Tap Water” (March 1996) and apamphlet by SAWARA and the League of WomenVoters, Home Water Treatment . Information on this

Appendix C. Additional Information

145

subject is also available from the Arizona WaterQuality Association (602) 947-9850.

Chapter 7: ROLES OF CITIZENSAND GOVERNMENT INWATER POLICY

William E. Martin, Helen Ingram and othersdescribed the development of Tucson’s waterpolicies and problems in Saving Water In A DesertCity, published in Washington, D.C. by Resourcesfor the Future in 1984. A more recent analysis canbe found in an article by Wilson, L.G., W.G.Matlock and K.L. Jacobs, Hydrologic Uncertainties andPolicy Implications: The Water Consumer Protection Actof Tucson, Arizona, USA. (Hydrogeology Journal.Vol. 6, pp. 3-14. 1998). A summary of the City ofTucson’s current water policies can be found in theCity of Tucson’s Mayor and Council Water Policies.Resolution No. 17929. Adopted January 26, 1998.For information about views of the CitizensAlliance for Water Security, email them [email protected]. Philip C. Metzgeranalyzed Tucson’s water management in To Master AThirsty Future: An Analysis of Water ManagementEfforts in Tucson, Arizona. (A Case Study Reportfrom the Water Resources Program, TheConservation Foundation, May 1984.)

Ensuring Arizona’s Water Quantity and Qualityinto the 21st Century contains a summary of lawspertaining to water quantity and water quality. Thisbackground report prepared by The University ofArizona for the 1997 Arizona Town Hall is availablefrom the Arizona Town Hall office in Phoenix.

Discussions of the Groundwater ManagementAct and its implementation are discussed in

“ADWR Developing Second Management Plan”(WRRC Arroyo Spring, 1987) and “TheGroundwater Management Act: Saving Water andDeveloping Water Policy” (WRRC Arroyo Spring1988). “Debate, Discussion Mark Ten-YearAnniversary of Arizona’s Groundwater ManagementAct” (WRRC Arroyo October 1990); Robert J.Glennon’s Because That’s Where the Water Is’: RetiringCurrent Water Uses to Achieve the Safe-Yield Objective ofthe Arizona Groundwater Management Act. ArizonaLaw Review 33:89 1991; State of Arizona Office ofthe Auditor General, Performance Audit of ArizonaDepartment of Water Resources, Report No. 99-8,April 1999.

General information about the Colorado RiverCompact is in WRRC’s August 1997 Arroyo,“Sharing Colorado River Water: History, PublicPolicy and the Colorado River Compact.”

Some problems confronting small watersystems are discussed in “Arizona’s Small WaterSystems Confront Questions, Uncertainties”(WRRC. Arroyo. October, 1991).

Regional water management is examined in“Regional Water Supply Agency, A New ArizonaWater Policy Concept” (WRRC Arroyo, April,1991).

Information about the Arizona Water BankingAuthority is available from the AWBA Web site.The Central Arizona Water Conservation District(Central Arizona Project) and Central ArizonaGroundwater Replenishment District also have aWeb site with current information.

A thorough discussion of Indian water rightsissues can be found in Indian Water Rights:Negotiating the Future published in 1983 by ElizabethChecchio and Bonnie Colby, available from theDepartment of Agricultural Economics, TheUniversity of Arizona. A shorter explanation can be

found in “Settlement of Indian Water Rights, aPriority Issue” (December 1989 WRRC Arroyo).

STATUTES DEALINGWITH WATER

Water QuantityARS (Arizona Revised Statutes) Title 45:

Chapter 1 deals with surface water laws; Chapter 2contains the Groundwater Code, including lawsdealing with water rights, transportation ofgroundwater, wells and artificial recharge; Chapter 3contains provisions for underground water storage;Chapter 8 contains flood control statutes and theremaining chapters deal with dams, irrigationdistricts and other matters.

Water QualityThe federal Clean Water Act is contained in 33

USC (United States Code) Chapter 26. Thisincludes laws controlling NPDES permits,wastewater treatment discharges, and relatedactivities.

43 USC contains the Safe Drinking Water Act.The National Environmental Policy Act of 1969 isin 42 U.S.C.4321-4347. CERCLA (or Superfund) iscontained in 42 USC - 9601 et seq.

Information about EPA regulations and waterquality standards is available from the EPA Web sitewww.epa.gov. This site also has a list of waterproviders in Pima County.

ARS Title 49 deals with environmentalmanagement, including water quality matters, withemphasis on groundwater protection. The ArizonaAdministrative Code, Title 18 Chapters 9 and 11contains specific regulations under the statutes.


146

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Aacidity 75acre-foot 19, 117Active Management Area 85, 92, 121ADEQ See Arizona Department of Environmental Qualityadjudication 96ADWR See Arizona Department of Water Resourcesagricultural water use 14, 56agriculture 14, 55algae 117alkalinity 72, 75, 77alluvium 117aquifer 1, 17 - 19, 25 - 27, 46, 49, 91, 97, 105, 117Aquifer Protection Permit 91, 121Arizona Corporation Commission 88, 95, 103, 105, 108, 121Arizona Department of Environmental Quality 16, 24, 32, 48, 86, 89, 91, 103, 121Arizona Department of Water Resources 46, 91, 100, 121Arizona Groundwater Management Act 121Arizona Native Plant Society 85Arizona Water Banking Authority 22, 72, 100, 121artesian well 117artificial recharge 21, 25, 28 - 29, 40, 93, 117Assured Water Supply 24, 26, 46, 93, 103, 107, 117, 121augmentation 33, 117Avra Valley 9, 13, 15, 17, 21, 26 - 27, 54 - 57, 63, 81, 83, 101Avra Valley Irrigation District 14, 56 - 58, 121

BBADCT See Best Available Demonstrated Control Technologybase flow 117basin 117basin and range province 1Beat the Peak 10, 50Best Available Demonstrated Control Technology 121Best Management Practice 96, 121biofilm 73

blending 80 - 81bonds 7- 8, 83, 103, 109bottled water 13, 82Buckeye 79

Ccalcium carbonate 118California 1 - 2, 20, 30, 80 - 81, 84, 98, 100Cañada del Oro 18 - 19CAP See Central Arizona ProjectCasa del Agua 32 - 33CAVSARP See Central Avra Valley Storage and Recover ProjectCentral Arizona Groundwater Replenishment District 22, 99, 101, 121Central Arizona Project 5, 22, 35, 38, 46, 57 - 58, 60 - 61, 64 - 65, 71, 75, 77, 81 - 82, 85, 99, 102, 104, 107, 117, 121, 123, 138Central Arizona Water Conservation District 13, 99 - 100, 121Central Avra Valley Storage and Recovery Project 16 - 17, 26, 121Central Wellfield 19, 29CERCLA See Comprehensive Environmental Response, Compensation and Liability Actchloramine 72, 75, 79, 84, 117chlorine 71 - 72, 75, 79 - 80, 83, 88, 117Citizen’s Water Advisory Committee 85Citizens Against the CAP 85Citizens Alliance for Water Security 85Citizens to Revise Arizona Water Law 85City of Tucson 8, 104, 106Clean Water Act 88, 90climate 1, 3CMID See Corataro Marana Irrigation Districtcoliform bacteria 117Colorado River 1, 5, 11 - 12, 22, 38, 71, 79 - 81, 83 - 84, 86, 96 - 98, 100Colorado River Compact 98Comprehensive Environmental Response, Compensation and Liability Act 117cone of depression 117constructed wetland 117consumptive use 117controversy, water (1975-76) 9, 54corrosivity 71, 81, 84, 117Cortaro Marana Irrigation District 46, 57, 58, 121


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Ddam 14, 30, 57, 81DDT 121desalinization 74, 79 - 80, 83, 117disinfection 23, 27, 47, 49, 68, 71 - 73, 75, 77, 79, 81, 83 - 84, 105disinfection byproducts 118distribution system 7, 24, 47, 72, 75, 79, 81, 118downgradient 118drawdown 118

Eeffluent 23 - 24, 47, 58, 118electrodialysis 79 - 80, 118, 121Emergency Water Conservation 105Endangered Species Act 102, 121Environmental Impact Statement 121Environmental Protection Agency 13, 24, 71, 91, 103, 121Environmental Quality Act 88, 90EPA See Environmental Protection Agencyevapotranspiration 3, 118

FFarmers Investment Company 57, 121Federal Agriculture Improvement and Reform Act of 1996 56Federal Emergency Management Agency 38, 104, 121filtration 23, 47, 71, 73, 79, 83, 118fire fighting 9flexibility account 118flood control 37flood control district 121flood hazards 36floodplain 38 - 39, 104, 118floodwater 30, 35Flowing Wells Irrigation District 13 - 14, 45, 71, 91, 103Fort Lowell 6

GGlendale 79golf course 15, 23 - 24, 45 - 47, 52, 55, 59, 68, 91, 95, 105 - 106gpcd 118

gradient, hydraulic 118graywater 32 - 33, 47 - 48Green Valley 7, 18, 23, 45, 57, 59, 69, 81, 91, 107groundwater 10, 118groundwater levels 18Groundwater Management Act 10, 46, 56, 92, 121groundwater savings facilities 26, 57 - 58, 99, 118Groundwater Users’ Advisory Committee 85

Hhardness 27, 65, 71 - 72, 77, 96, 118Hayden-Udall Water Treatment Plant 79, 83hazardous substances 66health 16, 32, 48, 61, 65, 69 - 70, 72, 75, 82, 86, 89, 91, 104 - 105history 5 - 6, 31, 79, 96

Iimpact fee 118in- lieu recharge 57, 118incidental recharge 25, 118Indian water rights 86, 96, 100industrial water use 59, 93, 95infiltration 118injection well 118ion exchange 80irrigation 5, 7, 14, 17, 25, 32, 47, 51, 56, 58, 79, 81, 86, 91 - 92, 95, 103, 105irrigation district 13, 57, 118Irrigation Nonexpansion Area 92

Llake 64, 101landfill 15, 66 - 67Las Vegas 79lawns 43, 45, 50 - 51, 54 - 55League of Women Voters 85Legislature 10 - 11, 25, 88, 92, 100 - 101, 109Lower Santa Cruz Replenishment Project 27

MManagement Plan 94

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Marana 14, 19, 56, 59, 69, 105Metropolitan Domestic Water Improvement District 13, 22, 44 - 45, 71, 103, 124Metropolitan Utilities Management Agency 15microbe 69, 72, 81microfiltration 74, 118, 121mineral content 118mining 13, 16, 25, 36, 43, 46, 59, 61, 67, 91, 97, 101mountain front recharge 118Multiple Benefits Water Project 38, 64municipal water use 43 - 44, 118

Nnanofiltration 74, 79 - 80, 118, 121National Environmental Protection Act 102natural recharge 19, 21, 25, 28 - 29, 35, 37, 40, 119Nevada 1, 55, 79, 98, 100Non Point Discharge Elimination System 121non-consumptive use 119non-point source 89non-renewable supply 20NPDES 88, 90 - 91

OOro Valley 13, 22, 27, 44 - 45, 105ozone 72 - 73, 75, 77, 79, 83 - 84, 119ozone-chloramine 83

PPantano Wash 68PCE 121permeability 119pH 66, 75, 81, 119Phoenix 1, 20, 22, 80, 92 - 93, 96, 104Pima Association of Governments 103, 106, 121Pima County 2, 10, 15, 20, 23 - 24, 37 - 40, 44, 47 - 49, 52, 54 - 55, 58, 66, 68, 83, 85 - 86, 90, 92, 97, 100, 103 - 105, 108Pima County Department of Environmental Quality 48Pima County Health Department 121Pima County Wastewater 89Pima Mine Road Recharge Project 64

plumbing code 48, 50, 105point source 88polyphosphate 77pools 33, 44, 50 - 52, 101population 1, 6 - 9, 20, 23, 43 - 44, 49, 52, 55, 64 - 65, 90, 93, 99, 104, 107potable water 119precipitation 2 - 3, 17, 31pretreatment program 68primary treatment 119private water utility 119protozoa 119public utility 119pumping 17, 57Pure Water Coalition 85

RRaytheon 16, 66recharge 119reclaimed water 23, 45, 47, 105, 119Regional Effluent Planning Partnership 24renewable supply 20, 22, 46reservoir 119reverse osmosis 74, 79 - 80, 82, 119, 121Rillito 1, 6, 18, 28 - 29, 35 - 36, 61, 63, 104Rillito Recharge Project 64riparian area 24, 35, 39, 61 - 63, 86Roger Road Wastewater Treatment Facility 47runoff 119

SSafe Drinking Water Act 16, 71, 88, 91, 104safe yield 24, 48, 93, 101, 103, 119salinity See total dissolved solidsSan Xavier 14San Xavier District 9, 35, 39, 57, 63, 97sand and gravel 18, 59, 61, 96Santa Cruz River vi, 1, 5 - 6, 8, 14 - 16, 19, 23, 27, 29, 31, 35 - 36, 38 - 39, 46, 49, 56 - 57, 61, 66 - 68, 86, 104 - 105Santa Cruz River Watershed Basin Study 39SAWRSA See Southern Arizona Water Rights Settlement Actscale 16, 28 - 29, 46, 53, 60 - 61, 72, 75, 84


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secondary treatment 119septic system 49, 69service area 119sewage 68, 119sewer 14, 119Sierra Club 85sludge 119sodium 119soft water 119soil-aquifer treatment 80, 119, 121Sonoran Desert 3Southern Arizona Water Resources Association 85Southern Arizona Water Rights Settlement Act 97, 121stormwater 36, 38 - 39, 41, 89 - 90Stormwater Plan 121stream 1, 14, 25, 28 - 29, 38, 40, 61 - 62, 65, 89subsidence 19 - 21, 28, 119subsurface water 119Superfund 65, 88, 91, 119Supreme Court 25, 86, 96, 98surface water 1, 6, 14, 17, 21, 38, 65, 71, 86, 88, 92 - 93, 96, 101, 119Sweetwater Underground Storage and Recovery Facility 23Sweetwater Wetland 16, 64, 68

TTAMA See Tucson Active Management AreaTanque Verde Wash 18taste 73, 80TCE See trichloroethlyeneTDS See total dissolved solidsterminal storage 99, 119tertiary treatment 120Tohono O’odham 12, 24, 97, 102total dissolved solids 12, 22, 27, 72, 79, 81 - 84, 120 - 121transmissibility 120transmission line 120treated wastewater 120treatment costs 84treatment plant 120trichloroethylene 16, 65 - 66, 71, 77, 80 - 81, 119, 121trihalomethane 72, 79, 120, 121Tucson Active Management Area 23, 32, 56, 58, 61, 86, 121

Tucson Airport Remediation Project 64, 66, 121Tucson International Airport 65Tucson Regional Water Council 85Tucson Water 7, 10, 16 - 17, 27, 32, 44 - 48, 50, 53 - 55, 66 - 68, 75, 77, 81, 83, 103 - 104Tucsonans for a Clean Environment 16, 85turbidity 120turf 16, 23

Uultrafiltration 74, 79underground storage facilities 64, 91, 99, 120 - 121underground storage tank 91Underground Water Storage, Savings, and Replenishment Program 26, 99, 120 - 121United States Geological Survey 20 - 21, 121USGS See United States Geological Survey

Vvadose zone 120vegetation management 31volatile organic compounds 120

Wwastewater 15, 17, 23 - 25, 47, 63, 68 - 70, 80, 88, 90 - 91, 97, 101, 104 - 105, 108, 126Wastewater Advisory Committee 85wastewater treatment 14, 23 - 24water budget 43, 49, 93 - 94Water CASA 32, 44, 48water conservation 8, 10, 32, 46, 49 - 50, 54 - 55, 60, 88, 93, 104 - 105, 108Water Conservation Alliance of Southern Arizona 121Water Consumer Protection Act 16, 23, 27, 67, 85, 104, 121, 123, 139water harvesting 31 - 32, 51water law 92water main 120water management 85, 88, 100, 104, 106 - 107water provider 5, 7, 13, 17, 22, 43 - 44, 46, 50, 54, 57, 71, 83, 86, 91, 93, 95, 99 - 100, 103, 105, 108, 124water quality 5, 13 - 14, 16, 41, 85, 88 - 89, 92, 103 - 104Water Quality Assurance Revolving Fund 91

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water rates 10, 14, 53 - 54, 83, 88, 95, 103, 108 - 109, 129water shortage 8water softening 73water table 1, 8, 17, 20 - 21, 25, 35, 49, 62, 88, 93, 106, 120water transfer 101water treatment 26, 65, 73, 75, 80, 83water waste ordinance 105watershed management 107weather modification 31wellfield 9, 17, 21, 26, 29, 49, 120well-injection 21wetland 15, 62, 67 - 68, 91, 120

Xxeriscape 105

Zzinc orthophosphate 77, 79

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