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WASTEWATER MASTER PLAN

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Table of Contents SECTION 1. Introduction .................................................................................................. 1

1.1 Background ............................................................................................................ 1 SECTION 2. Existing Wastewater Infrastructure ................................................................. 3

2.1 Collection System ................................................................................................... 3 2.1.1 Gravity Mains ................................................................................................... 3 2.1.2 Force Mains ...................................................................................................... 3 2.1.3 Dry Sewer Areas ............................................................................................... 3

2.2 Lift Stations ............................................................................................................ 4 2.3 Wastewater Treatment Plant ................................................................................... 4 2.4 Reclaimed Water Pipeline ........................................................................................ 6 2.5 Existing Permits ...................................................................................................... 6

SECTION 3. Planning ........................................................................................................ 8 3.1 Existing Service Areas ............................................................................................. 8 3.2 Population Projections ............................................................................................. 8

SECTION 4. Wastewater Loads ....................................................................................... 11 4.1 Wastewater Generation Rates ................................................................................ 11 4.2 Wastewater Projections ......................................................................................... 12 4.3 Wastewater Peaking Factors .................................................................................. 14

SECTION 5. Model Development ..................................................................................... 16 5.1 Modeling Software Selection .................................................................................. 16 5.2 GIS Database ....................................................................................................... 16 5.3 Data Sources ........................................................................................................ 16 5.4 Modeling .............................................................................................................. 17

5.4.1 Collection System ........................................................................................... 17 5.4.2 Lift Station ..................................................................................................... 17 5.4.3 Elevations ...................................................................................................... 18 5.4.4 Operational Information .................................................................................. 18 5.4.5 Model Calibration ............................................................................................ 18

SECTION 6. Future Wastewater Infrastructure ................................................................. 19 6.1 Future Collection System ....................................................................................... 19

6.1.1 Gravity Main ................................................................................................... 19 6.1.2 Force Main ..................................................................................................... 19 6.1.3 Extending sewer main within Town’s Limit ....................................................... 19 6.1.4 Connecting Dry Sewered to Town Sewer Main .................................................. 19

6.2 Future Lift Stations ............................................................................................... 20 6.3 Future Wastewater Treatment Plant ....................................................................... 20 6.4 Future Reclaimed Water Pipeline ........................................................................... 21 6.5 Future Reclaimed Water Reservoir ......................................................................... 22 6.6 Future Recharge and Recovery Facilities ................................................................ 22 6.7 Future Permits ...................................................................................................... 22

WASTEWATER MASTER PLAN

V:\Engineering\Projects\13-048 Cave Creek Master Plans\09 Reports\2.0 Wastewater Master Plan\Final\TOCC Wastewater Master Plan_Revision.doc

SECTION 7. Capital Improvement Plan ............................................................................ 23 SECTION 8. References .................................................................................................. 29

List of Tables Table 2-1 Summary of Existing Sanitary Sewer System Components ...................................... 3 Table 2-2 Existing Lift Station Summary ............................................................................... 4 Table 2-3 Water Ranch WRF Design Summary ...................................................................... 5 Table 2-5 Existing Permits ................................................................................................... 7 Table 4-2 Population and Wastewater Flow Projections ....................................................... 13 Table 5-1 GIS Datasets ..................................................................................................... 16 Table 6-1 Future Lift Station Summary ............................................................................... 20 Table 6-2 Future Wastewater Treatment Plant Capacity ...................................................... 20

List of Figures Figure 1-1 Location of Town ................................................................................................ 1 Figure 1-2 Location of Abandoned WWTP and Water Ranch WRF .......................................... 2 Figure 3-1 Population Project Comparison ............................................................................ 8 Figure 3-2 Combined Population Growth Projection ............................................................. 10 Figure 4-2 2012 Wastewater Generated by Billing Type ....................................................... 12 Figure 4-3 Wastewater Flow Projections ............................................................................. 13 Figure 4-3 Peaking Factors ................................................................................................ 15 Figure 6-1 Future Wastewater Treatment Plant ................................................................... 21 Appendices

Appendix A – Model Results Appendix B – Cave Creek WRF Hydraulic Profile and Process Flow Diagrams Appendix C – Upsize Sewer Summary

Town of Cave Creek, AZ Wastewater Master Plan

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SECTION 1. Introduction

1.1 Background The Town of Cave Creek (Town) is located in Maricopa County, Arizona and was incorporated in 1986. At an elevation ranging between 2,000 and 3,060 feet above sea level, the Town is home to a population of 5,015 people1. Bounded by unincorporated Maricopa Country to the north, Phoenix to the west and south, Carefree to the east, and Scottsdale to the southeast, the Town of Cave Creek encompasses approximately 29 square miles.

Figure 1-1 Location of Town

The Town recently abandoned their 0.233 million gallons per day (MGD) package wastewater treatment plant (WWTP), which was located on Rancho Mañana Boulevard in order to build a new water reclamation facility (WRF) that could better handle current and future projected flows. The new facility, Water Ranch, began operation in November 2010 is located along the north side of Carefree Highway at 44th Street, east of Cave Creek Wash, as shown in Figure 1-2. The previous package plant has been abandoned and a lift station was built at its location to pump all wastewater to the new facility.

1 2010 US Census

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Town of Cave Creek, AZ Wastewater System Master Plan

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Figure 1-2 Location of Abandoned WWTP and Water Ranch WRF


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SECTION 2. Existing Wastewater Infrastructure

2.1 Collection System Wastewater is largely collected via gravity sewer collection system. Some isolated portions of the system drain to a local lift station before being pumped to a nearby gravity section. Approximately 90% of the wastewater flows are ultimately routed to the Rancho Manana lift station before being pumped to the Water Ranch Water Reclamation Facility (WRF) constructed in 2010. The Water Ranch WRF has a current rated capacity of 0.71 MGD and is located along the north side of Carefree Highway and 44th Street. This plant is the sole wastewater treatment plant to service the Town of Cave Creek.

2.1.1 Gravity Mains The Town’s sanitary sewer system consists of 6 through 16 inch sewer lines and has three interceptors. The first is located within the right-of-way of Cave Creek Road and runs east to west by gravity to collect wastewater from commercial areas. The second interceptor also runs east to west and is located south of the first interceptor. This sewer line collects wastewater from the remaining commercial areas and a small residential area. The third interceptor, running south to north by gravity, collects wastewater from Town Hall north to Rancho Mañana Boulevard.

In 2010 as part of the Water Ranch project a 12in sanitary sewer was constructed along the north side of Carefree Highway to accept flows from the commercial areas along Carefree Highway and the forcemain discharge from the Rancho Manana lift station. The flows are ultimately conveyed to the influent pump station at the Water Ranch WRF.

2.1.2 Force Mains There are two force mains connecting small residential areas to the gravity sewer system. The connection points for this system are located at the Desert Creek Subdivision and on the Conestoga Trail. Pumps located at individual homes are used to deliver these flows to the sewer system. The force mains at this location were not included in the model network, however, sewer flows generated in those areas were routed to the closest manholes.

2.1.3 Dry Sewer Areas A majority of the Town still remains as dry sewer. However, a large portion (west of Cave Creek Wash) is planned to be sewered as contained within this document.

Table 2-1 Summary of Existing Sanitary Sewer System Components

Component Unit Quantity

Gravity Sewer Lines

6 inch Feet 242

8 inch Feet 49,019


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Component Unit Quantity

10 inch Feet 2,815

12 inch Feet 8,116

15 inch Feet 2,061

16 inch Feet 2,104

Total (Feet) 64,357

Manholes Each 315

Forcemains

4 inch Feet 321

6 inch Feet 4,181

8 inch Feet 14,744

Total (Feet) 19,246

2.2 Lift Stations The Town is responsible for the operation and maintenance of three lift stations. One is located to the north of the abandoned WWTP and a second to the south of this site. The lift station to the north of the old WWTP pumps wastewater collected from the Rancho Manana subdivision to the old WWTP, while the lift station to the south pumps the remainder of the Town’s wastewater flows to the same location. With the construction of the new Water Ranch WRF, an additional lift station has been constructed so that flows enter the system as they always have but are then pumped from the abandoned site to the Water Ranch WRF.

Table 2-2 Existing Lift Station Summary

Lift Station ID Location Forcemain Dia (in) Head

(feet)* Flow

(gpm)*

54th Street LS 54th St and Chuparosa Ln. 6 30 42

Ranch Manana 5600 E. Rancho Manana 8 90 450

Stagecoach Pass Stagecoach Pass Estates 6 60 70

Total (gpm) 562

Total (mgd) 0.81

* Flow and head are based on existing wet weather model runs.

2.3 Wastewater Treatment Plant The following table summarizes the design criteria utilized in the design of the Water Ranch WRF regarding influent flows from the Operations and Maintenance Manual for the facility. The WRF produces Class A+ effluent.


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Table 2-3 Water Ranch WRF Design Summary

Design Criteria Units Value

Average Annual Day Flow MGD 0.71

Peak Hour Flow MGD 2.0

BOD ppd 2,587*

TSS ppd 3,137*

TN ppd 286*

Ammonia ppd 193*

*Based on 0.66 MGD. After grease program, capacity was increased to 0.71 MGD.

Site plan for the Water Ranch WRF is shown in the Figure 2-1.

Figure 2-1 Water Ranch WRF Site Plan

The 12in PVC gravity sewer main enters the WRF at the southeast corner and combines with flows from the facility drain through an 8in PVC gravity drain in the influent pump station (IPS). This pump station includes a wet well, two submersible pumps, and a valve vault complete with check and isolation valves.

Large solids are removed from the influent stream via an in-channel rotary drum screen and then continue towards the grit removal system. Secondary treatment (nitrification and

Influent Pump Station

Lab/Admin Building

Process Building

SBR

Chemical Facility

Filters

CCB


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denitrification) is controlled by two sequencing batch reactors which fill, react, settle and clarify the wastewater. Waste activated sludge (WAS) is pumped to the sludge holding tanks before dewatering via a belt filter press to create sludge cake for landfill disposal.

Following secondary treatment and prior to the tertiary filters, SBR effluent is sent to equalization basins in order to minimize the hydraulic surges to the downstream processes.

Tertiary filtration is performed by cloth disc filters and followed by chlorination in the three chlorine contact basins. The plant has the ability to discharge directly to the adjacent Cave Creek Wash, for emergencies only. Should this discharge be required, the facility has the ability to dechlorinate the effluent prior to discharge.

2.4 Reclaimed Water Pipeline Once the water has been treated at Water Ranch, effluent is conveyed to the storage ponds located on the Rancho Mañana Golf course via an 8in ductile iron reuse forcemain. The reclaimed water forcemain transports the water along Carefree Highway to Cave Creek road, turns north on Cave Creek Road, turns west on Rancho Mañana Boulevard, turns north at the west side of the golf course maintenance facility then discharges into the storage ponds. The golf course utilizes the reclaimed water for irrigation purposes whenever it is needed. There is also a telescoping valve located inside of the reclaimed water wet well to create a point source discharge to Cave Creek Wash, which is located near the abandoned wastewater treatment plant site, within the Town limits. This discharge is permitted by the AZPDES permit was created to be used only in an emergency.

2.5 Existing Permits Water Ranch WRF meets Class A+ reclaimed water standards as stated in the Table 2-5. The golf course is the primary means of discharging effluent under reclaimed water permit. However, in case of emergency, WRF can discharge to the wash as permitted Arizona Pollutant Discharge Elimination System (AzPDES) Permit.

Table 2-4 Water Ranch Class A+ Reclaimed Water Monitoring Requirement

Sampling Point Number Sampling Point Identification Latitude Longitude

2 Reclaimed Water Wet Well (Downstream of CCB)

33° 48' 0.18" N 111° 59' 29.28" W

Parameter DL Units Sampling Frequency Reporting Frequency

Fecal Coliform:

Single-sample maximum 23.0 CFU or MPN Daily Quarterly

Fecal Coliform: Four (4) of

last seven (7) samples Non-Detect CFU or MPN Daily Quarterly


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Total Nitrogen: Five-sample rolling geometric mean 10.0 mg/l Monthly Quarterly

Turbidity: Single reading 5.0 NTU Everyday Quarterly

Turbidity: 24-hour average 2.0 NTU Everyday Quarterly

Enteric Virus: Four of last seven samples Non-detect PFU Monthly/Suspended Quarterly

Table 2-5 summarizes all the existing permits for Water Ranch WRF.

Table 2-5 Existing Permits

Permit Type Permit No. Description

Aquifer Protection Permit (APP)

Plant ID: 135581

LTF: 49432

Standards for reclaimed water monitoring at Rancho Mañana Golf Course. The Golf Course is the primary means of discharging effluent.

Arizona Pollutant Discharge Elimination System (AzPDES)

Plant ID: 135581

LTF: 49429

Standards for effluent discharges to Cave Creek Wash. Discharge to the Wash only occurs during an emergency.

Reclaimed Water General Permit Program General

Standards for reuse of reclaimed water used at the Golf Course


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SECTION 3. Planning

3.1 Existing Service Areas The existing sewer system consists of approximately 230 acres of active sewer as well as approximately 260 acres of dry sewer. The existing active sewer service areas identified by the Town represent those areas that are currently connected to the existing sanitary sewer system, thus contributing flows to the WRF.

3.2 Population Projections Various population projects exist for the Town of Cave Creek. These sources include: Arizona Department of Economic Security (ADES), Maricopa Association of Governments (MAG), Town of Cave Creek (TOCC) 2005 General Plan and United States (US) Census. The data from these various sources are presented below compared to US Census population.

Figure 3-1 Population Project Comparison

As shown, the population projections presented in the TOCC 2005 General Plan very closely predicted the population for 2010 (approximately 1.874% growth per year). Therefore, these population projections will be used for the purposes of this report. Due to the fact that Carefree and Desert Hills areas do not have accurate population projections, the growth projection for Cave Creek will be utilized for these areas also.


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Two population growth scenarios were considered. One with normal growth projection at 1.874% and another with accelerated growth of 3.75%. As seen in the Figure 3-1, if accelerated growth happens, than TOCC will see buildout capacity of 8600 units by 2022.

Table 3-1 shows the population projection for TOCC, Desert Hills, Carefree and combined of all system for both growth scenarios.

Table 3-1 Population Projections

Year

TOCC Projection (# Served)

DHS Projection (# Served)

Carefree Projection

(# Served)2 Combined Population

1.874% Growth

3.75% Growth

1.874% Growth

3.75% Growth

1.874% Growth

3.75% Growth

1.874% Growth

3.75% Growth

2012 5,114 5,811 2,159 1,229 1,229 2,159 8,502 9,199 2015 5,407 6,490 2,282 1,260 1,260 2,411 8,949 10,161 2020 5,933 7,801 2,504 1,300 1,300 2,898 9,737 11,999 2025 6,510 8,600 2,748 1,300 1,300 3,484 10,558 13,384 2030 7,143 8,600 3,015 1,300 1,300 4,188 11,458 14,088 2035 7,838 8,600 3,308 1,300 1,300 5,034 12,446 14,934 2040 8,600 8,600 3,630 1,300 1,300 6,052 13,530 15,952

Figure 3-2 shows graph of combined population growth within the system.

2 Carefree growth projections provided by Town of Carefree


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Figure 3-2 Combined Population Growth Projection


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SECTION 4. Wastewater Loads

4.1 Wastewater Generation Rates Data received from TOCC was analyzed for the period between January 2012 and December 2012. Based on that data, Water Ranch WRF received total of 76.3 MG of wastewater for the year. As discussed in the Water Master Plan, 2 person per dwelling unit (ppdu) and 2.49 ppdu were considered throughout the report. Based on the number of sewer connection, it was determined that average wastewater generation per sewer connection was 400 gal/day. This equates to 200 gpcd and 160 gpcd for 2 ppdu and 2.49 ppdu respectively.

As discussed in the Water Master Plan, water demand is 250 gpcd and 200 gpcd for 2 ppdu and 2.49 ppdu respectively. This indicates wastewater to water (WW/W) ratio of 0.8. This ratio is used to determine wastewater projection for the future.

Figure 4-1 shows the wastewater flow variation throughout the year of 2012. As seen from the graph, high flows were recorded in late winter, early spring months while in summer months, wastewater entering the plants decreased.

Figure 4-1 2012 Ratio of Monthly Wastewater Flow to Average Flow


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For year 2012, wastewater generated by billing type is shown in the Figure 4-2.

Figure 4-2 2012 Wastewater Generated by Billing Type

As seen from the graph, wastewater generated is mostly from the residential units followed by commercial and restaurants.

4.2 Wastewater Projections As population continues to increase in the Cave Creek area, wastewater flows will also increase. As discussed earlier for planning purposes, the current population is assumed to be generating between 200 and 160 gpcd which correlates to 2 ppdu and 2.49 ppdu, respectively. By the year 2040, it is estimated that 50% of the newly added population will be connected to the sanitary sewer system.

Table 4-2 shows the projected population that will be connected to the sewer connection and contribute to the flows entering Water Ranch WRF and wastewater flows for 2 ppdu and 2.49 ppdu.


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Table 4-1 Population and Wastewater Flow Projections

Year

Population with Sewer

Connection at 2 PPDU

Population with Sewer

Connection at 2.49 PPDU

WW Flow* (mgd) at 2 PPDU

WW Flow* (mgd) at 2.49 PPDU

Growth at

1.874%

Double Growth

at 3.75%

Growth at

1.874%

Double Growth

at 3.75%

Growth at

1.874%

Double Growth at

3.75%

Growth at 1.874%

Double Growth

at 3.75%

2012 1,045 1,045 1,307 1,307 0.209 0.209 0.209 0.209 2015 1,269 1,526 1,530 1,787 0.254 0.305 0.245 0.286 2020 1,663 2,446 1,924 2,707 0.333 0.489 0.308 0.433 2025 2,073 3,138 2,335 3,399 0.415 0.628 0.374 0.544 2030 2,523 3,490 2,785 3,751 0.505 0.698 0.446 0.600 2035 3,017 3,913 3,279 4,174 0.603 0.783 0.525 0.668 2040 3,559 4,422 3,821 4,683 0.712 0.884 0.611 0.749 * WW Flow = Existing + 50% of New connection added

Figure 4-3 shows graphical representation of the wastewater flow projections based on 1.87% and 3.75% growth rates with 2 ppdu and 2.39 ppdu.

Figure 4-3 Wastewater Flow Projections


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The above flow projections are solely based on increased flows due to population growth. There is the potential for additional commercial flow to be added to the collection system along Carefree Highway.

The CIP has captured this increase in total plant capacity (0.98mgd average annual day). In tracking plant flows and permitting of additional commercial in this area, Cave Creek will be able to adjust to these unknown impacts without exceed system capacity.

The collection system along Carefree Highway is adequately sized for this additional commercial flow up to the manhole where Estrado de Cholla dry sewer flows are proposed to be discharged. From that point into the plant, this gravity sewer needs to be upsized to 16” and is captured in the CIP.

4.3 Wastewater Peaking Factors Average wastewater flow projections were developed based on the above illustrated population projections and wastewater generation rates.

Peak hour flows were calculated based on the average wastewater generation and population served as described in the following equation (ADEQ Bulletin 11).

QMax/QAvg = 5.0/P1/6

Where: QMax/QAvg - Peak Hour Peaking Factor

P - Population in thousand

An analysis was performed for the population growth shown in the Table 4-2. As these calculations are empirical, it is important to notice that actual flow data can often provide better, more accurate information than these regulatory equations.

Also, smaller systems such as TOCC’s often require larger peaking factors to account for the increased potential of rapid changes in sewer flows.


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Figure 4-4 Peaking Factors


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SECTION 5. Model Development

5.1 Modeling Software Selection InfoSewer 7.6 wastewater modeling software distributed by Innovyze was used to model the wastewater collection system. An extended period simulation was used to model the dry weather and wet weather responses for existing and future scenarios over a 24-hour period with a time step of one minute. A Manning’s n coefficient of 0.013 was assumed for the entire pipe network. Demands were calculated for each parcel based on the number of dwelling units and planned zoning, and then those loads were applied to the appropriate nodes (manholes) within the hydraulic model.

5.2 GIS Database Various GIS datasets were developed to support the hydraulic modeling efforts, including ones for pipelines (i.e., gravity mains, forcemains), manholes, lift stations, and parcels. The following table lists the types of model data developed for each dataset.

Table 5-1 GIS Datasets

Pipelines Manholes Lift Stations Parcels

Diameter

Length

Upstream Invert

Downstream Invert

Friction Coefficient

Diameter

Rim Elevation

Headloss Coefficient

Hydraulic Loading

Wetwell Diameter

Wetwell Depth

Pump Capacity

Pump Controls

Land Use Type

Flow Generation

Phasing

Manhole Assignment

Information for the physical components of the model (e.g., pipelines, manholes, lift stations) were directly imported into the InfoSewer model. The parcel GIS dataset was used to apply hydraulic loads onto the model. Each parcel in the project boundary was assigned to a specific system manhole and identified as either connecting to the existing collection or connecting to the collection system in the future (e.g., dry sewered areas). Additionally each parcel was assigned a land use type of either residential, commercial, or vacant so that the appropriate wastewater generation rate and diurnal curve could be applied to the system from each parcel.

5.3 Data Sources Information from the previous wastewater collection system master plan was reviewed so the results of this master plan were consistent with and built upon previous efforts.

Record drawings of the existing collection system were used to apply information about the physical attributes (e.g., rim and invert elevations, lengths, pipe diameters) to the model.


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Maricopa County GIS data were obtained and used so that parcels connected under the existing and future collection system scenarios could be identified. The County GIS parcel dataset also included information on the land use type of each parcel. The land use data was used to apply the appropriate wastewater generation rates (i.e., residential or commercial) as hydraulic loads to the model.

5.4 Modeling

5.4.1 Collection System 5.4.1.1 Gravity Main

The modeled gravity mains within the Town’s collection system were assessed to determine the system capacity over a 24-hour period. The depth-to-diameter ratio (d/D) was calculated for each gravity main segment (i.e., manhole to manhole) for each minute over the model simulation. Upon completion of the model run, the maximum d/D experienced during the day is recorded for each gravity main segment. This value is used to assess the capacity of each gravity main segment. 5.4.1.2 Force Main

The information used to model the Town’s forcemains, included pipe diameter, pipe length, and Hazen-Williams friction factor. The flow from the connected lift station is modeled over the simulation period of 24-hours. The velocity and headloss is calculated for each time step (i.e., each minute) of the simulation. Graphs showing the output of the calculated velocity and headloss are reviewed so that these values remain within expected and acceptable ranges.

5.4.2 Lift Station Under the existing conditions scenario, three lift stations were represented in the model (i.e., 54th Street LS, Rancho Manana LS, and Stagecoach Pass Estates LS). The wetwell dimensions, pumping capacities, and pump level controls were applied to each lift station to convey the wastewater entering the station through the associated forcemains to the terminating gravity manhole.

Under the future conditions scenario, the 54th Street LS and the Rancho Manana LS continued to operate as defined in the existing conditions scenario. The Stagecoach Pass Estates LS was deactivated and flow which had been entering that station was allowed to flow by gravity through the proposed dry sewered area. A proposed lift station to the north of Carefree Highway and northeast of the Water Ranch WRF was modeled to convey the flow from the dry sewered areas directly north of Carefree Highway to the 12” gravity line running along the same highway. Additionally, the proposed lift station at 24th Street and Carefree Highway was modeled to convey the flow from the dry sewered areas west of Cave Creek to the wastewater treatment plant.


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5.4.3 Elevations Elevation data is critical to the accuracy of a hydraulic model of a gravity collection system. The hydraulic capacity of the components of the system is directly related to their respective invert and rim elevations. Rim elevations, invert elevations, pipe diameters, and lengths used for each pipeline and manhole in the sewer model were taken from record drawings so that the model accurately represented the available system information.

5.4.4 Operational Information A residential flow rate of 200 gallons per capita per day was used for the modeling process under existing conditions. After analyzing total residential flows, the commercial flow rate was calibrated against the flow records on hand from the wastewater treatment plant. This ensured total flows entering the plant in the model accurately reflected actual flow data recorded.

For the modeling process under future conditions, the residential flow rate was calibrated against the expected 2040 population of 4540 connected to the sewer collection system. The same commercial flow rate per acre under existing conditions was utilized for future conditions.

Typical residential and commercial diurnal curves were applied to the flows originating from each parcel based on the recorded land use for that parcel. Implementing diurnal curves in an extended period simulation allows flows from individual parcels to be modeled and represented over the course of the day to investigate how peak flows during the day combine and the impact that has on the capacity of each component in the system.

Additional hydraulic loads were applied to the collection system model to analyze the effect of wet weather and inflow and infiltration (I/I). The volume of I/I entering the collection system was determined to be 114,000 gpd based on an analysis of the flows entering the wastewater treatment plant over the year. This volume of I/I was distributed evenly across the collection system and applied to the model using a typical rainfall dependent I/I curve. The I/I curve represents the sudden influx of flow during a storm event from inflow (e.g., flow through manhole covers, cross connections) and the prolonged entry of flow into the system from infiltration (e.g., groundwater entering the system through cracks and pipe joints). The peak of the storm event was aligned with the peak of the diurnal curve in the model simulation to evaluate the system capacity under the “worst-case” situation for this modeled wet weather event.

5.4.5 Model Calibration Results for dry and wet weather scenarios under existing conditions were calibrated against the flow records at the wastewater treatment plant. This was done to analyze the accuracy of the wastewater generation rates and diurnal curves applied as loads to existing scenario. Once the calibration efforts of the existing flows was complete and a level of confidence in the applied wastewater generation rates was reached, the same generation rates were applied to future scenarios.


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SECTION 6. Future Wastewater Infrastructure

6.1 Future Collection System As most of TOCC Town Core is developed and currently has sewer, most of the future collection systems will be developer driven. As such, these future facilities will more than likely be provided by the individual developer, reviewed and approved by the Town.

Future developments within the TOCC service area should be applied to the model provided by this report to validate no impact to upstream and/or downstream facilities.

6.1.1 Gravity Main Current modeling of the gravity collection system shows that the existing system does not exceed 0.5 d/D and maintains greater than 3ft of freeboard in the manholes under wet-weather flow events.

Future modeling of the gravity collection system reveals 3,600lf of 8in and 3,800lf of 12in piping that needs to be upsized to maintain d/D ratios less than 0.8 under future wet-weather scenarios. However, while these sections of gravity sewer do result in full-pipe conditions, the upstream and downstream manholes still maintain a freeboard greater than 3ft. These sections of pipe are shown in the CIP for upsizing to provide a conservative capacity in these areas of the system.

6.1.2 Force Main The existing forcemains are operating within their design conditions and show no cause for upsizing. Repairs or rehabilitation may be required as these pipes tend to experience H2S corrosion.

6.1.3 Extending sewer main within Town’s Limit Extension of the sewer main within the Town’s limit shall be review on a case-by-case basis. However, Appendix A illustrates the current d/D (flow depth / pipe diameter) within the Town’s collection system. Typically sewers have available capacity until the d/D reaches 0.80.

6.1.4 Connecting Dry Sewered to Town Sewer Main Currently there are not any plans to connect large sections of existing Town residents/commercial to the gravity sewer system as long as their septic systems keep functioning. However, this document has evaluated the addition of these areas to the collection system and treatment plant and find no major issues regarding system capacity.

The modeling and CIP provides for infrastructure to connect sewer to the following dry-sewered areas:

- Estado de Cholla

- Hidden Valley

- Town annexed areas west of Cave Creek Wash


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6.2 Future Lift Stations Current dry sewered areas to the west of Cave Creek are depicted in Appendix A. These two areas represent approximately 4 square miles of land. Utilizing the 2010 US Census figure of 132 people per square mile, the anticipated flow rate at 100 gpcd from these two future areas is estimated to be 52,800 gpd.

Sufficient topography exists in these particular areas to gravity flow the sewer to a potential lift station site near Carefree Highway and 24th Street. Approximately 13,000lft of 6in forcemain would then be constructed to convey the lift station flows to the Water Ranch WRF.

Table 6-1 Future Lift Station Summary

Lift Station ID Forcemain Dia (in) TDH

(feet) Average Flow

(gpm)

54th Street 6 30 22

Rancho Manana 8 110 220

24th St and Carefree Highway 8 120 110

Estado de Cholla (North of Carefree Highway)

8 35 260

Total (gpm) 612

Total (mgd) 0.88

6.3 Future Wastewater Treatment Plant The current capacity at Water Ranch is 0.71 MGD. It is recommended that existing facility be expanded to when the flows at the facility reaches 80% of its rated capacity. Based on projections previously described, this threshold will be reached in the years between 2022 and 2037, depending on the growth of the service area. For the purposes of conservative planning, this expansion has been schedule for 2022. At that time, an additional 0.30 MGD process train needs to be added. According to projections, this capacity should be able to support the system through 2040.

Table 6-2 Future Wastewater Treatment Plant Capacity

Treatment Plant Location Average Annual Flow Treatment Capacity (MGD)

Existing WRF Capacity Water Ranch 0.71

0.25 MGD Addition Water Ranch 0.30*

Total 1.01

*0.1MGD for future commercial, 0.2MGD for future population

Figure 6-1 shows the wastewater projections, future capacity required at the Water Ranch WRF and when 80% of existing capacity will be reached at the plant.


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Figure 6-1 Future Wastewater Treatment Plant

6.4 Future Reclaimed Water Pipeline The TOCC currently disposes of the reclaimed effluent generated at the Water Ranch WRF via a forcemain to the Rancho Manana golf course. A brief review of the reuse pump data provided within the Water Ranch O&M suggests that the existing reclaimed effluent pumps will be capable of pumping approximately 1MGD through the 8in forcemain given the following estimates:

- Total Forcemain Length = 27,000 ft

- Elevation Change = 200 ft

Current effluent flow meter data at the WRF indicates that the facility is currently discharging on an annual average basis approximately 0.25 MGD, therefore the existing pumps and forcemain will be sufficient for many years of service. When the Cave Creek population reaches 8,600 (buildout), the WRF influent flow is estimated at 0.884mgd. If the additional 100,000gpd is realized for future commercial, the estimated effluent flow will be 0.98MGD.


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6.5 Future Reclaimed Water Reservoir The TOCC is currently not pursuing any future storage reservoirs regarding WRF effluent.

6.6 Future Recharge and Recovery Facilities As reclaimed water flows continue to increase, the TOCC will begin to explore the options of utilizing an Underground Storage Facility (USF) to obtain recharge credits for the effluent not used at the golf course.

The installation of a vadose zone well has been programmed into the CIP for year 2023 after the WRF expansion is completed.

6.7 Future Permits The following future permits are anticipated as being required:

- Groundwater Recharge:

o Underground Storage Facility (USF) from ADWR

o Water Storage Permit (WSP) from ADWR

o ADWR Recharge Well Drilling Permit

- WRF Expansion

o Aquifer Protection Permit (APP) major modification for flow increase

o Arizona Pollutant Discharge Elimination System (AZPDES) major modification for flow increase

TOCC should maintain their current AZPDES, APP and Reuse Permits in compliance with ADEQ as these permits are becoming increasingly difficult to obtain. Furthermore, ADEQ has initiated increased scrutiny regarding regulatory compliance and enforcement.


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SECTION 7. Capital Improvement Plan The Capital Improvement Plan (CIP) outlines projects required to meet future growth and hydraulic conditions within the Town of Cave Creek sanitary sewer system. The CIP is packaged into recommended projects for 2014 through 2040 based on current needs and future development.

Town of Cave Creek, Arizona Wastewater Master Plan

11/22/2013

Page | 24

Table 7-1 Proposed Sanitary Sewer System Capital Improvement Plan

ID Improvement Description Year

Estimated Construction Cost (2013)

Town Development Driven

1 WRF Influent Flow Meter and Bypass Flow Meter Provide flow meter to accurately determine return

flows at WRF.

2014

$12,000

2 Manhole Rehabilitation Program (5 manholes/year)

The Manhole Rehabilitation Program was created to update 5 manholes per year based on current manhole conditions. The program will continue each year until all deteriorated manholes have been rehabilitated.

$25,000

2014 Subtotal $37,000 $0



2015

$25,000

4 Sewer Upsizing Upsize to 10in sewer from MH167 to MH161, total length of 360lft and 2MHs $90,000

5 Sewer Upsizing Upsize to 14in sewer from MH559 to RM Lift Station, total length of 54lft and 1MHs $27,720

6 Remote Monitoring Improvements at Stagecoach Pass Lift Station Adding instruments/comm to remotely monitor lift

station via internet website. $10,000

2015 Subtotal $152,720 $0



2016

$25,000



10 Remote Monitoring Improvements at 54th Street Lift Station Adding instruments/comm to remotely monitor lift

station via internet website. $10,000

2016 Subtotal $177,380 $0

11 Sewer Upsizing Upsize to 10in sewer from MH174 to MH173, total length of 267lft and 2MHs 2017

$76,050


Town of Cave Creek, Arizona Wastewater System Master Plan

11/22/2013

Page | 25






$25,000

2017 Subtotal $142,630 $0

14 Sewer Upsizing Upsize to 10in sewer from MH175 to MH174, total length of 121lft and 1MHs

2018

$36,150


16 Retrofit existing neighborhoods (Black Mountain Vista, Desert Forest Park,

Surrey Hills) for sewer service

Installation of 27,155 linear feet of 8-inch PVC gravity sewer piping in existing

residential streets. This will include removing and replacing existing pavement. The

average depth of the sewer pipe installation is 7 feet deep, requiring approximately

78 manholes each 4 feet in diameter. No railroad crossing or bores are expected.

$3,119,000

17 Lift station at Carefree Highway and 24th Street to new WWTP

Installation of a lift station, a 6-foot-diameter manhole structure, approximately 20 feet deep, with a minimum

of three pumps (two active, one standby). The lift station should be designed to accommodate the

following flow situations: Low (average day conditions): Q

= 180 gpm High (maximum day, peak-hour conditions): Q

= 330 gpm High (maximum day-plus III, peak-hour conditions):

Q = 510 gpm

New electrical feed, I&C will be required in addition to site development and mechanical connections.

$416,000

18 6-inch force main to connect lift station at Carefree Highway and 24th Street to

new WWTP

Installation of 13,000 linear feet of 6-inch ductile-iron force main with cathodic protection. The force main

should accommodate 200 psi working pressure. Average depth of installation will be 4 feet in soft rock

with no dewatering expected. It is assumed that removing and replacing the existing pavement will be required along the entire length of the force main. No

railroad crossing or bores are expected.

$2,221,000



$25,000


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Town Development Driven 2018 Subtotal $196,510 $5,756,000


2019

$72,900




$25,000

2019 Subtotal $232,720 $0


2020

$78,000


25 Connect dry sewerd areas near Estado de Cholla

Provide piping, site, lift station, forcemain and associated ROW/easement acquisition to convey dry

sewered area to Carefree Highway gravity line. $520,000



$25,000

2020 Subtotal $758,360 $0


2021

$33,450




$25,000

2021 Subtotal $203,575 $0


2022

$33,750




$25,000

33 WRF Expansion Provide an additional 0.3MGD expansion at the existing WRF plant for growth related flows. $1,500,000 $1,500,000


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Town Development Driven 2022 Subtotal $1,645,173 $1,500,000


2023

$66,600


36 8-inch gravity sewer system to connect Apache Wash annexation to lift station at Carefree Highway and 24th Street

Installation of 10,600 linear feet of 8-inch PVC gravity sewer piping along a minor arterial. This will include

removing and replacing existing pavement. The average depth of the sewer pipe installation is 8 feet deep, requiring approximately 29 manholes, each 4 feet in diameter. Some dewatering is expected. No

railroad crossing or bores expected.

$1,595,000

37 Install monitoring/vadose recharge well Install vadose zone recharge well to dispose of excess effluent in winter months. $100,000



$25,000

2023 Subtotal $271,880 $1,595,000


2024

$69,150




$25,000

2024 Subtotal $201,633 $0


2025

$39,150




$25,000

2025 Subtotal $114,370 $0

45 Sewer Upsizing Upsize to 10in sewer from MH231 to MH516, total length of 122lft and 1MHs 2030

$36,300



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50 Sewer Upsizing Upsize to 14in sewer from MH583 to MHWRF Plant, total length of 86lft and 1MHs $33,480




$125,000

2030 Subtotal $516,380 $0


2035

$91,125




$125,000

2035 Subtotal $289,610 $0



2040 $125,000

2040 Subtotal $125,000 $0

Total Cost $5,064,940 $8,851,000


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SECTION 8. References Following references were used to prepare this master plan:

1) Town of Cave Creek, General Plan, 2005.

2) Town of Cave Creek, Water Master Plan, 2008.

3) Town of Cave Creek, Sanitary Sewer Master Plan, 2006

4) Town of Cave Creek, Water and Wastewater Data for 2012 and 2013.

5) Town of Carefree, Growth Projections.

Appendix A

Model Results

Appendix A1

Cave Creek Existing Dry Weather

Town o

f Cave C

reek

Waste

water C

ollectio

n Syste

m Mode

lExi

sting

Dry We

ather

0 1,500 3,000750

Feet

¯

Date Printed: Nov 2013

Land UseCOMMERCIAL

RESIDENTIAL

VACANT

LegendPipesMaximum d/D

0.5~0.70.7~0.80.8~0.99

< 0.5

> 0.99

ManholesFreeboard (ft)

0~11~33~6> 6

< 0

Forcemain

Parcels

54th St LS

Rancho Manana LS

Stagecoach PassEstates LS

WWTP

Appendix A2

Cave Creek Existing Wet Weather

Town o

f Cave C

reek

Waste

water C

ollectio

n Syste

m Mode

lExi

sting

Wet W

eather

0 1,500 3,000750

Feet

¯


Land UseCOMMERCIAL

RESIDENTIAL

VACANT


0.5~0.70.7~0.80.8~0.99

< 0.5

> 0.99


0~11~33~6> 6

< 0

Forcemain

Parcels

54th St LS

Rancho Manana LS

Stagecoach PassEstates LS

WWTP

Appendix A3

Cave Creek Existing and Future Pipes

Town o

f Cave C

reek

Waste

water C

ollectio

n Syste

mPip

esExi

sting vs

. Future

0 2,500 5,0001,250

Feet

¯


LegendPipes

Existing

Future

Appendix A4

Cave Creek Future Dry Weather

Town o

f Cave C

reek

Waste

water C

ollectio

n Syste

m Mode

lFut

ureDry

Weath

er

0 2,500 5,0001,250

Feet

¯


Land UseCOMMERCIAL

RESIDENTIAL

VACANT


0.5~0.70.7~0.80.8~0.99

< 0.5

> 0.99


0~11~33~6> 6

< 0

Forcemain

Parcels

54th St LSRancho Manana LS

North ofCarefree Highway LS

WWTP

24th Street &Carefree Highway LS

Appendix A5

Cave Creek Future Wet Weather

Town o

f Cave C

reek

Waste

water C

ollectio

n Syste

m Mode

lFut

ureWe

t Weath

er

0 2,500 5,0001,250

Feet

¯


Land UseCOMMERCIAL

RESIDENTIAL

VACANT


0.5~0.70.7~0.80.8~0.99

< 0.5

> 0.99


0~11~33~6> 6

< 0

Forcemain

Parcels



WWTP


Appendix A6

Cave Creek Future Wet Weather – Upsizing by 2”

Town o

f Cave C

reek

Waste

water C

ollectio

n Syste

m Mode

lFut

ure We

t Weath

erAfte

r 2" CIP

Upsizi

ng

0 2,500 5,0001,250

Feet

¯


Land UseCOMMERCIAL

RESIDENTIAL

VACANT


0.5~0.70.7~0.80.8~0.99

< 0.5

> 0.99


0~11~33~6> 6

< 0

Forcemain

Parcels



WWTP


Appendix A7

Cave Creek Future Wet Weather – Upsizing by 4”

Town o

f Cave C

reek

Waste

water C

ollectio

n Syste

m Mode

lFut

ure We

t Weath

erAfte

r 4" CIP

Upsizi

ng

0 2,500 5,0001,250

Feet

¯


Land UseCOMMERCIAL

RESIDENTIAL

VACANT


0.5~0.70.7~0.80.8~0.99

< 0.5

> 0.99


0~11~33~6> 6

< 0

Forcemain

Parcels



WWTP


Appendix B

Cave Creek WRF Hydraulic Profile and Process Flow Diagrams

All Units are MGD Sending Structure

Collection system

Influent P.S. Headworks SBR 1 SBR 2

Post EQ. Basin Filter 1 Filter 2

Chlorine Contact Basin

Sludge Holding

TankSolids

Dewatering TotalReceiving Structure

Influent P.S. 0.660 0.013 0.013 0.015 0.009 0.710Headworks 0.710 0.710SBR 1 0.355 0.355SBR 2 0.355 0.355Post EQ. Basin 0.342 0.342 0.684Filter 1 0.342 0.342Filter 2 0.342 0.342Chlorine Contact Basin 0.329 0.329 0.658Reclaimed Water P.S. 0.658 0.658Sludge Holding Tank 0.013 0.013 0.026Solids Dewatering 0.011 0.011Solids Disposal 0.002 0.002

Appendix C

Upsize Sewer Summary

*All Manhole numbers are under the field “MOID” in the referenced ArcMap file*

Existing 8” Pipes Requiring Upsizing under Future Wet-Weather Scenario

US Manhole [MOID]

DS Manhole [MOID]

Increased Size [in]

Length [ft]

167 161 10 360 173 171 10 168 174 173 10 267 175 174 10 121 402 502 10 246 502 241 10 280 282 233 10 103 233 257 10 105 404 444 10 204 444 330 10 221 330 231 10 141 231 516 10 122 516 360 10 110 360 468 10 236 468 416 10 170 416 359 10 248 256 459 12 350 459 258 12 238

Total Length (10”) 3,102 Total Length (12”) 588

Existing 12” Pipes Requiring Upsizing under Future Wet-Weather Scenario

US Manhole [MOID]

DS Manhole [MOID]

Increased Size [in]

Length [ft]

559 RM Lift Station 14 54 560 559 14 351 44 560 14 131

568 569 14 452 576 577 14 449 577 578 14 452 578 579 16 450 579 580 16 249 580 581 14 246 581 582 16 353 582 583 14 179 583 WRF Plant 14 86 562 563 14 350

Total Length (14”) 2,750 Total Length (16”) 1,052

Cave Creek WW MP CoverTOCC Wastewater Master Plan_RevisionSECTION 1. Introduction1.1 Background

Figure 1-1 Location of TownFigure 1-2 Location of Abandoned WWTP and Water Ranch WRFSECTION 2. Existing Wastewater Infrastructure1.12.1 Collection System2.1.1 Gravity Mains2.1.2 Force Mains2.1.3 Dry Sewer Areas

Table 2-1 Summary of Existing Sanitary Sewer System Components1.12.2 Lift Stations

Table 2-2 Existing Lift Station Summary2.3 Wastewater Treatment Plant

Table 2-3 Water Ranch WRF Design SummaryFigure 2-1 Water Ranch WRF Site Plan2.4 Reclaimed Water Pipeline2.5 Existing Permits

Table 2-4 Water Ranch Class A+ Reclaimed Water Monitoring RequirementTable 2-5 Existing PermitsSECTION 1.SECTION 1.SECTION 1.SECTION 1.SECTION 1.SECTION 1.SECTION 3. Planning3.1 Existing Service Areas3.2 Population Projections

Figure 3-1 Population Project ComparisonTable 3-1 Population ProjectionsFigure 3-2 Combined Population Growth ProjectionSECTION 4. Wastewater Loads4.1 Wastewater Generation Rates

Figure 4-1 2012 Ratio of Monthly Wastewater Flow to Average FlowFigure 4-2 2012 Wastewater Generated by Billing Type1.14.2 Wastewater Projections

Table 4-1 Population and Wastewater Flow ProjectionsFigure 4-3 Wastewater Flow Projections4.3 Wastewater Peaking Factors

Figure 4-4 Peaking FactorsSECTION 5. Model Development5.1 Modeling Software Selection5.2 GIS Database

Table 5-1 GIS Datasets5.3 Data Sources5.4 Modeling5.4.1 Collection System5.4.1.1 Gravity Main5.4.1.2 Force Main

5.4.2 Lift Station5.4.3 Elevations5.4.4 Operational Information5.4.5 Model Calibration

SECTION 6. Future Wastewater Infrastructure6.1 Future Collection System6.1.1 Gravity Main1.1.16.1.2 Force Main6.1.3 Extending sewer main within Town’s Limit6.1.4 Connecting Dry Sewered to Town Sewer Main

6.2 Future Lift Stations

Table 6-1 Future Lift Station Summary6.3 Future Wastewater Treatment Plant

Table 6-2 Future Wastewater Treatment Plant CapacityFigure 6-1 Future Wastewater Treatment Plant6.4 Future Reclaimed Water Pipeline6.5 Future Reclaimed Water Reservoir6.6 Future Recharge and Recovery Facilities6.7 Future Permits

SECTION 7. Capital Improvement PlanTable 7-1 Proposed Sanitary Sewer System Capital Improvement PlanSECTION 8. References

Appendices Combined

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