Rangeland Precipitation Monitoring Workshop Report 15 June ... · Michael A. Crimmins, Mitchel P....

1

Rangeland Precipitation Monitoring Workshop Report

15 June 2017; Miami, AZ

Organizers

Michael A. Crimmins, Mitchel P. McClaran, Julie Brugger

Supported by Western Extension Risk Management Education Grant: Reducing livestock

productions and legal risks from increased climate variability by co-developing tools for

ranch-scale drought detection

Prepared 15 August 2017

Executive Summary

This report documents the objectives, activities, and outcomes of the Rangeland

Precipitation Monitoring Workshop, the culminating workshop of the project, Reducing livestock

productions and legal risks from increased climate variability by co-developing tools for ranch-

scale drought detection, funded by the Western Extension Risk Management Education

Program. This workshop build on the activities and outcomes of two previous workshops where

ranchers with grazing permits and US Forest Service range managers (the Working Group) co-

developed a design for a rugged rain gauge to be deployed in remote areas that makes collecting

precipitation information easier, faster, and more accurate, and a reporting and data-sharing web-

based application (myRAINgeLog.arizona.edu) to compare recorded precipitation values to

current estimates based on PRISM climate data and the estimated historic records using the

Standardized Precipitation Index (SPI). The objective of this workshop was to introduce these

ranch-scale drought detection tools to a wider audience. To that end, the Research Team

advertised the Workshop on the Gila County Cattle Growers website, the Arizona Section of the

Society for Range Management listserv, and extended individual invitations.

There were 36 participants in the Workshop in addition to the Team members. They

included Working Group members, additional ranchers with grazing permits on the TNF,

ranchers from other areas of Arizona, FS personnel new to the TNF, and Bureau of Land

Management and Natural Resources Conservation Service personnel. The Workshop provided

participants with: 1) a description of the co-development process; 2) background about the

standardized precipitation index (SPI); 3) the rationale for the design of the rain gauge and a

description of the construction process: and 4) a demonstration of the myRAINgeLog app. They

were also provided with: a rain gauge to take home and test, copies of the Do-it-yourself

construction guide: Rugged accumulation precipitation gauge for remote monitoring and the

Range Gauges for Range Management: Precipitation Monitoring Best Practices Guide, and the

URL for myRAINgeLog.

Attendance and evaluations indicate that the Workshop met its intended objectives. All

participants found the Workshop valuable and a large majority had a favorable opinion of the

ranch-scale drought detection tools and said they were likely to use them. They also

overwhelmingly agreed that the Workshop helped them to think differently about how to manage

their risk from drought.

2

I. Introduction

Increased climate variability will increase drought severity and frequency on western US

rangelands. Drought creates both production and legal risks because ranches typically rely on

federal lands for 50-90% of their forage, and policies for these 200M acres of federal rangeland

dictate responses regarding herd reduction, reduced access to forage, and a lengthy approval

process to change infrastructure and management. In Arizona, the patchy spatial distribution of

drought means that some ranches experience drought while others do not (McClaran and Wei

2014). Because the spatial resolution of drought information is too coarse to represent this

difference among ranches, the objective of the Ranch-Scale Drought Detection Project was to co-

develop, with ranchers and federal land managers, tools to more precisely detect drought at the

ranch scale and training material that encourages and supports ranchers and federal land

managers to collect data at new sites throughout the region to increase the level of precipitation

monitoring. The goal of the project is to help ranchers and federal land managers reduce the

production and legal risk of drought and increase resilience to drought. We consider the tools

and training material elements of a ranch-scale drought early warning system.

The tools co-developed include a design for a rugged

rain gauge to be deployed in remote areas that makes

collecting precipitation information easier, faster, and

more accurate, and a reporting and data-sharing web-

based application (myRAINgeLog.arizona.edu) to

compare recorded precipitation values to current

estimates based on PRISM climate data and the

estimated historic records using the Standardized

Precipitation Index (SPI). Outputs also include a Rain

Gauge Construction Guide (Appendix A) and a

Precipitation Monitoring Best Practices Guide (Appendix B)

The Ranch-Scale Drought Detection Project builds on our ongoing (2014-2017) National

Oceanic and Atmospheric Administration (NOAA) Sectoral Applications Research Program

(SARP) funded project, “Using a co-development process to improve, integrate and encourage

use of drought information and adaptive management of livestock grazing on National Forests”

(the Co-development Project). In that project, ranchers and FS co-developed solutions to

increase preparedness for drought. We use the SPI to represent the severity of drought because

the drought policy of FS Region 3 (Arizona and New Mexico) uses SPI as a trigger: “In the

Southwestern Region, anytime the SPI reaches a value of minus 1.00 or less for the preceding 12

month period, grazing allotments should be evaluated for existing drought conditions” (R3

Manual Supplement to 2209.13.19.1). Participants in that project gained a greater understanding

of the spatial variation of SPI among ranches, the value of detecting drought with SPI at the

ranch scale with the installation of rain gauges, and the need for long-term measurements at each

gauge to calculate the SPI for current conditions. This quote from an evaluation form following

our second workshop (August 2015) illustrates their interest in ranch-scale precipitation

monitoring: “Set up ranchers with rain gauges in many pastures and set them up to obtain SPI

measures and extrapolations on their allotments.”

3

II. Outline of the project

The project was organized as three workshops in which the University of Arizona project team

(the Team) and ranchers with grazing permits and U.S. Forest Service (FS) range managers on

the Tonto National Forest (TNF) in Arizona participated. Figure 1 shows the organization with

initial projected workshop dates. Workshop agendas can be found in Appendix C. The first two

workshops were discussion oriented, in which participants, known as the Precipitation

Monitoring Working Group, discussed ideas for the design of rain gauges, precipitation

monitoring best practices, and a recording and reporting application for precipitation data, tested

them out in practice, and iteratively improved the designs. The Team then incorporated these

ideas into building an actual gauge and application and a best practices guide which would be

presented to a larger audience in Workshop III.

Figure 1: Organization of the Ranch-Scale Drought Detection Project

a. Pre-workshop consultation

The workshops were preceded by consultation with an Advisory Group of three ranchers who

were already participating in the Co-development Project. Consultation began in April 2016 and

resulted in: 1) an initial design for a rain gauge; 2) a request for guidance on flexible

precipitation monitoring approaches for gauges that may be read infrequently, the cost-benefit of

different approaches, and how to select the best approach for an operation based on decision

making needs; 3) a request for online tools designed to support a spectrum of different

precipitation monitoring approaches, and; 4) suggestions for whom to invite to the first

workshop. These suggestions were incorporated into a prototype rain gauge and a prototype

“Precipitation Logbook Generator” application to be distributed at Workshop I.

4

b. Workshop I

The first workshop was held June 30, 2016 in Payson, AZ. A total of 19 participants in addition

to the Team included ranchers and FS personnel who were participating in the Drought Project,

FS personnel new to the TNF, a Gila County Extension Agent, and Arizona Game and Fish

Department personnel.

Mike Crimmins opened the workshop by describing the purpose and organization of the project

and the Working Group’s role as co-developers. Next he discussed the calculation and use of

drought indices and the advantages and disadvantages of different types of rain gauges. To seed

the discussion of best practices for precipitation monitoring, he asked participants to describe

what they are currently doing. He then displayed Figure 2, which asks them to consider where

the optimum cost-benefit, or “sweet spot,” is between density of gauges and frequency of

monitoring for their operation based on their decision making needs.

Figure 2: Schema for considering how many gauges to have and how often to read them.

After lunch, Mike Crimmins demonstrated the prototype rain gauges he had constructed based on

the suggestions of the Advisory Group (Figure 3) and a prototype “Precipitation Logbook

Generator” (Figure 4). Features of the prototype gauges that make them easier, faster, and more

accurate to read include: clear plastic UV-resistant tubing, a ruler mounted on the gauge, a screen

at the top to prevent the entry of foreign objects, and in some, a valve at the bottom for priming

and draining the gauge. The Logbook Generator allows users to develop supporting reference

climatology information for new monitoring sites by entering geographic coordinates. It

generates hard copy charts that can be used in the field for data collection (plotting of current

5

observation on reference chart) as well as roughly estimating SPI drought index values based on

similar percentiles for new precipitation observations.

Figure 3: Mike Crimmins explaining the features of different rain gauge prototypes.

6

Figure 4: Output of “Precipitation Logbook Generator with precipitation observations

plotted.

Participants were given different prototype rain gauges to take home and test over the upcoming

monsoon season in order to provide more feedback on the gauges and the logbook application at

the next workshop. Meanwhile, the Team began to incorporate suggestions from participants

into the design of an interactive web-based application for recording precipitation data and

comparing it to estimated historic records to improve on the “Precipitation Logbook Generator,”

and working with the Cyber Communications and Technologies (CCT) Team in the College of

Agriculture and Life Sciences to develop the application

An online survey to obtain feedback on workshop #1 was also distributed to participants in late

July. Six respondents provided positive feedback with five responding that the workshop was

valuable or very valuable in the information that it provided. Respondents indicated that they

valued learning how to read and use cumulative precipitation plots and were pleased with the

initial rain gauge prototypes discussed at the workshops.

b. Workshop II

The second workshop was held on November 2, 2017 in Payson, AZ. A total of 17 participants

in addition to the Team included many of the Workshop I participants and a Mojave County

Extension Agent.

Mike Crimmins opened the workshop by describing how his backyard gauges had performed

over the summer and then elicited comments from participants about how their gauges had

performed. Figure 5 shows some of the rain gauges installed by the Working Group. Having

7

actual experience with the gauges, participants were able to offer many valuable suggestions for

improving the design and for recording and using the observations. They discussed the best type

of oil to use, the use of a funnel to reduce undercatch, methods of preventing vandalism, an

improvement to the ruler mounting, and the need for information about how to obtain the parts

needed to construct the gauges. Evidence was provided that suggests that wider (4-inch) gauges

under-collected precipitation compared to the 2-inch gauges. There was a consensus that having

the clear gauges increased the frequency of reading them.

Figure 5: Rain gauges installed by Working Group members.

Participants also discussed where to locate the gauges and how often to read them. Suggestions

for locating them include: high and low elevations of pastures; places that you pass by often

waters; and key monitoring areas. They agreed that although it is time-consuming to read them

even once a month, information about the timing and frequency of precipitation events is

valuable. Mitch McClaran suggested the strategy of checking gauges in the next pasture you are

going to, rather than where you came from. Participants also discussed the value of including

supporting data, such as photographs, along with precipitation observations.

After a break, Mike showed mock-ups for the recording and reporting application to be called

myRAINgeLog. He also explained how myRAINgeLog would be different from other

agriculturally oriented weather monitoring web applications like FarmLogs. FarmLogs was

suggested as a potential tool to help ranchers track precipitation at remote sites, but had some

shortcomings discussed in this workshop and the previous one. The myRAINgeLog application

was being designed specifically to log and analyze precipitation observations that are made

infrequently (weeks or months between observations) which is a common practice for remote

range monitoring sites. The application was also being designed to ingest and display gridded

8

precipitation estimates, much like FarmLogs, but is using a different product (PRISM)

specifically designed to capture topo-climatic variability that is endemic to the western U.S. .

The PRISM dataset used in myRAINgeLog is better at taking elevation into account when

interpolating data from surrounding official observation sites.

Participants were very enthusiastic about the app and suggestions for improvements flowed

freely. One of the ranchers stated: “I see this app, you could just keep adding things to it, and

really do something that you could use to manage a western ranch.” Some of participants’

suggestions included:

1. Ability to use some features of a mobile app without cell service, such as entering data.

2. Multiple accounts/user and/or users/account.

3. Using GPS to locate gauges and notify of proximity.

4. Using a map layer to display location of gauges.

5. Alerts when rain has been recorded near gauge location.

The discussion of desired features for myRAINgeLog continued after lunch and was followed by

a discussion of best practices. There was a consensus that precipitation monitoring data is not

for making hard and fast management decisions, but just one tool in the toolbox of things that

can provide some situational awareness of what’s going on. As one rancher put it: “And so as

we move forward I think we need to make it very clear that this is simply one tool, or this is

simply one metric that get can used to try to paint the picture.” Mike Crimmins summarized the

discussion this way: “It’s not about trigger points and decisions, numbers don’t equal direct

actions, but that this is a tool and this is about decision support, is maybe the way to think about

it, that it’s another piece of information to bring to it.” OR As The workshop concluded with a

discussion of how to encourage the adoption of best practices among a broader group of ranchers

and land managers and how to organize the final workshop, whom to invite and how to get the

word out, and how it should be organized.

Workshop evaluations (n=14) indicated that all respondents found the two Workshops valuable,

all but one found it extremely valuable. For many the most valuable aspect was the shared

learning and relationship building between ranchers and FS, described as “Gets everybody on

same page,” and “Helped bridge gaps between FS and permittees. Put us all on the same team.”

All but one respondent agreed that the Workshops increased their understanding of the

calculation and use of drought indices, best practices for installing ranch-scale precipitation

monitoring, how precipitation data can be used for livestock management decision making, and

that the information from the Workshops helped them manage their risk from drought. All but

two agreed that the Workshop increased their understanding of how to analyze and interpret

precipitation data. All but one agreed that the information and tools generated in the Workshops

would be valuable to other ranchers and land managers.

The Team incorporated suggestions for improving the rain gauge design into building new

gauges, a Construction Guide for the gauges, and a Best Practices Guide for the final workshop.

They continued to work with the CCT team to incorporate desired features in myRAINgeLog

with the goal of having a beta ready for the Workshop III. In order to share information learned

and tools developed with a broader group of ranchers and land managers in Workshop III, the

9

Team advertised the Workshop on the Gila County Cattle Growers website, the Arizona Section

of the Society for Range Management listserv, and extended individual invitations.

III. Workshop III Summary

Workshop III took place on June 15, 2017 in Miami, AZ. There were 36 participants in addition

to the Team members. They included Working Group members, additional ranchers with

grazing permits on the TNF, ranchers from other areas of Arizona, FS personnel new to the TNF,

and Bureau of Land Management and Natural Resources Conservation Service personnel.

a. Introduction

Mitch McClaran opened the Workshop by explaining the project to the new audience and

introducing them to SPI basics that are crucial for understanding how to use the precipitation

monitoring tools that would be introduced. He first reminded them how SPI is used in FS

Region 3 as a drought indicator. SPI has the advantage of providing a “standardized” indicator

that is adjusted to the magnitude of precipitation expected in an area (Quiring 2008). Therefore,

an SPI value representing high (relatively wet) elevations expresses the same drought severity in

low (relatively dry) elevations. In addition, SPI values represent the likelihood of occurrence and

therefore provide a measure of threat frequency (Table 1). For example, an SPI value of -1 or

less occurs about 16% of the time in a long term record (~1 in 6 years or 16 times in 100 years),

and a value of -2 or less occurs about 2.3% of the time (~1 in 43 years or 2.3 times in 100 years).

Finally, SPI values can be estimated for any specific location, and therefore the measurements

collected from a specific rain gauge or from a large region will represent that location.

Table 1. Probability of Occurrence for Standardized

Precipitation Index (SPI) Values

SPI Value Probability Category

> 2.0 2.3% Extremely Wet

1.5 to 1.9 4.4% Very Wet

1.0 to 1.4 9.2% Moderately Wet

-0.9 to 0.9 68.2% Near Normal

-1.0 to -1.4 9.2% Moderately Dry

-1.5 to -1.9 4.4% Very Dry

< -2.0 2.3% Extremely Dry

The 114-year record for low, middle and high elevation locations (Figure 6) in Tonto National

Forest illustrates how SPI provides a “standardized” indictor that is not affected by the

magnitude of precipitation expected in an area (Quiring 2008). In this example, the SPI values

(12 months from Jan-Dec) for the three elevations behave very similarly through last 100 years.

In keeping with the probabilities of occurrence (Table 1), SPI -2 values occurred 4 times in the

114-year record (3.5%), and values less than SPI -1 occurred 19 times (16.6%).

10

It is also possible to distinguish winter (October through May) and summer (June through

September) drought conditions rather than combine them in to a 12-month period. Figure 7

shows the relationship between SPI values and departures from average precipitation for summer

and winter seasons on Tonto National Forest for the previous 100 years. The comparison clearly

shows that summer (June through September) precipitation is much less variable across the 100

years than winter (October through May). Summer values ranged from ~3 to 12 inches, while

winter ranged from ~4 to 30 inches. That difference in variability directly translated into smaller

percentage of average winter precipitation (58% of average = 42% decrease from average) at SPI

-1 than the percentage of average summer (72% of average = 22% decrease from average). The

same was true for SPI -2, with only 34% of average for winter and 52% of average for summer.

Figure 6: Standardized precipitation index (12 month Jan-Dec) for three elevations in Tonto

National Forest from 1900 through 2014. Low elevation is < 4500 ft, mid elevation is 4500-5500 ft

and high elevation is > 5500 ft.

11

Average

Average

Summer

-1 SPI 72% of average

5.1 of 7.0”


3.5 of 7.0”

Winter


7.7 of 13.2”


4.5 of 13.2”

Figure 7. Distribution of summer and winter precipitation values for Tonto National Forest, 1915-

2014. Average (red) summer (7 inches, June-September) and winter (13.2 inches, October-May),

and corresponding SPI -1 (blue) and SPI -2 (green) values of precipitation, and the respective

percent of average for the two SPI values.

12

b. Best Practices

Mike Crimmins then described the problem the tools are addressing: lack of local-scale

precipitation data. Most official climate monitoring networks have high densities of

observations in and around urban area with many fewer observations in rural and remote

wilderness areas where public land grazing occurs. This means that regional drought monitoring

tools have greater uncertainty in these areas where range management decisions are being made.

Figures 8 and 9 show an example for the TNF where there are very few weather stations

collecting regular observations and large areas where observations have to be estimated by

interpolation techniques (e.g. PRISM climate). The development of a new rain gauge design and

accompanying decision support tools was intended to support the deployment and regular use of

rain gauge observations at these key allotment and pasture locations not covered by existing

weather stations.

Figure 8: Official weather stations in the vicinity of the Tonto National Forest.

13

Figure 9: Gridded climate data for the vicinity of the Tonto National Forest.

The rugged PVC rain gauge

designed to capture cumulative

precipitation over long periods

is ideal for range management

applications and has long been

used by ranchers and land

managers to gather precipitation

data at key monitoring sites.

Crimmins reviewed the

rationale for the new rain gauge

design and how to construct

one. The innovation of using

clear PVC and adding an

emptying valve makes the

reading and maintenance of a

remote rain gauge even easier,

encouraging more frequent

readings over time. Details can

be found in the Do-it-yourself

construction guide: Rugged

accumulation precipitation

gauge for remote monitoring

(Appendix A).

14

The cumulative nature of the precipitation observations in this type of gauge can be plotted as

curves that represent total precipitation over different time periods. To aid in the interpretation

of these curves, reference climatologies (first introduced in the Precipitation Logbook Generator)

based on historical, gridded climate data (e.g. PRISM climate grids) can be developed for any

location. Plotting rain gauge observations on these curves can give an indication of whether or

not that observation is wetter or drier than the historical estimates for that location. This can be

further coupled to drought contingency plan where certain actions are taken if a precipitation

observation is lower than expected at a certain date (Figure 10).

Figure 11: How rain gauge observations can be coupled to a drought contingency plan.

Crimmins next discussed Best Practices for managing and using precipitation data, how many

gauges to install and where, and collecting additional supporting observations. He addresses the

“sweet spot” question: how many gauges, and where. Some suggestions include:

• Tie rain gauge location to existing plans – collect data at locations where you need to

know if it rained or not to discern impacts

• Collect data at house, ranch headquarters, or ranger station – easy spots for frequent

monitoring

• Place gauges in locations you drive by often – gauges that are readily accessible for quick

visits near roads that allow for more frequent observations.

• Use topography as a guide – bracket areas with gauges at high and low locations

• No such thing as ‘too many gauges’ – gauges are cheap and will collect data for long

periods

He also suggested collecting additional supporting observations, such as notes on or

measurements of forage amounts, forage conditions, spring flows, or tank levels. Over time,

15

these will help you interpret your precipitation observations. More information can be found

in Range Gauges for Range Management: Precipitation Monitoring Best Practices Guide

(Appendix B).

c. Online Precipitation Monitoring Tool

After lunch, Mitch McClaran gave a demo of the online precipitation monitoring tool,

myRAINgeLog (https://myraingelog.arizona.edu/), and discussed how it can be used to assist in

range management decision making.

Users have a main page that displays all the gauges,

gauge locations on a map, and the log of precipitations entries on the right. Selecting a specific

gauge from the list results in a display of the Rainfall Chart showing the recorded precipitation

between the time periods defined in the Set Range field. Changing the dates in the Set Range

field will change the values presented in the Rainfall Chart. Users will want to change the Set

Range dates to represent different times of the year, as well as different years of values shown in

the Rainfall Chart.

After selecting the Set Range dates, the user can

generate a Report of the SPI probabilities and

PRISM-based estimates of rainfall for the rain

gauge location and the dates selected in the Set

Range.

The Blue values show the measurements record

in the rain gauge, and the accumulation of

precipitation between the dates selected in the

Set Range. The orange line shows the PRISM-

based estimates of accumulated precipitation

16

during the time period. The dashed lines represent the SPI values estimated for this locations

and time period (as in its predecessor, the Precipitation Logbook Generator). The top line

represents the 97.7 percentile or SPI = 2. The next dashed line represents the 84.0 percentile of

SPI = 1. The middle dashed lines is the 50th percentile, indicated that historically half the values

fall above and half above that line. The next lowest dashed line represents the 16.0 percentile or

SPI = minus 1, and the lowest dashed line represents the 2.3 percentile or SPI = minus 2.

Clicking on the legend for Observation Rainfall, Estimated Rainfall and Historical Rainfall will

turn-off and turn-on those displays in the chart.

In the example for Huerfano of accumulated precipitation between 11/01/2016 and 06/11/2017,

the blue line shows the monthly precipitations values recorded in the gauge. Most of the

precipitation occurred in December 2016 and January 2017, and during that time the

accumulated values was slightly below the 50th percentile historically. However, the small

amount of precipitation since January brought the curve below the 16th percentile (SPI = -1).

The Orange Estimated Rainfall line provides three important pieces of information:

1) compares the magnitude recorded in the gauge to the estimated amount (which line is

higher and which lower);

2) the estimated frequency of rainfall events on a daily basis, where the frequent rains in

December and January are represented as short, ascending steps. In contrast, if the rain

occurred in a single day then there would be a single large step in the accumulation

curve.; and

3) estimated rainfall beyond the date of the late recording of rainfall, which indicates the

likelihood that some rain may have accumulated in the rain gauge but has not yet been

recorded.

This Report provides information to support management decisions about the expectations of

forage production in the area and the likelihood that surface water will be in catchment for

livestock to drink. Specifically, the magnitude (height of the curve) of precipitation in reference

to the historic values gives a sense of how dry conditions might be during a growing season or

during a season when catchments are likely to full from runoff. More importantly, the type of

stair-steps of the orange Estimated Rainfall line suggests whether the daily pattern of rainfall

provided for a long periods of soil moisture and resulting abundance of forage production, or

whether the pattern was only one or two rainy days that provided only a short growing season

and therefore less forage production than the total accumulated precipitation might suggest.

One can imagine that having this information for each pasture in a grazing allotment would

provide estimated of what condition may be present before livestock enter a pasture. This

estimate can help plan the number grazing days in each pasture, which of course would be

validated with a visit to the pastures.

Participants were very enthusiastic about myRAINgeLog and were eager to see work continue on

features suggested earlier but not implemented yet, such as alerts and public maps and gauges.

They also suggested several new features, such as being able to compare observation data

between years, showing allotment boundaries on the map of gauges, and being able to import

and export data.

17

d. Wrap up

Throughout the Workshop and at its conclusion, both Crimmins and McClaran emphasized that

the tools and Guides are still under development and that participants’ feedback was needed to

improve their utility. Participants were provided with a rain gauge to take home and test, copies

of the Do-it-yourself construction guide: Rugged accumulation precipitation gauge for remote

monitoring and the Range Gauges for Range Management: Precipitation Monitoring Best

Practices Guide, and the URL for myRAINgeLog. They were asked to complete evaluation

forms. By the next day, many had already created myRAINgeLog accounts.

e. Evaluation of Workshop

We received 24 evaluations (Appendix D). Overall, evaluations were extremely positive. All

respondents found the Workshop valuable, 79% Extremely Valuable. Twelve commented that

they found learning about myRAINgeLog the most useful part; six found learning about the rain

gauge most useful. One commenter summarized what was most useful as: “Ability to gather

data in an easy to use and see way.”

Ninety-six percent of respondents had a Very or Somewhat Favorable opinion of the design of

the rain gauge. One who found it Somewhat Favorable commented it was “too costly.” Eighty-

seven percent indicated they were Very Likely to use one of the gauges; 92% indicated they were

Very or Somewhat Likely to build their own gauges using the design.

Fifty-four percent of respondents felt that the Workshop increased their understanding of best

practices for ranch-scale precipitation monitoring Greatly and 33% Moderately. One commenter

felt that we did not do a very good job of explaining how to “use precipitation monitoring for

grazing.” Forty-six percent felt that the Workshop Greatly increased their understanding of how

to analyze and interpret precipitation data they have collected; 54% Moderately. A respondent

whose understanding increased Moderately suggested we could do a better job of explaining,

“How to use it in everyday rancher operation. How to use it in long range planning or change.”

Seventy-one percent of respondents were Very Likely to use myRAINgeLog to archive and

interpret their precipitation records; 16.7% were Somewhat Likely. A respondent who was

Unlikely to use it commented that it should be made “Simpler.”

It looks like we could have done a better job of discussing how precipitation data can be used for

livestock management decision making (Greatly 25%; Moderately 66.7%) and how to use the

information to plan pasture rotations and interpret vegetation monitoring data (Very Likely to

use 29.2%, Somewhat Likely 62.5%). Twenty-one percent of respondents felt that information

from the Workshop Greatly helped them think differently about how to manage their risk from

drought; 75% Moderately. Some comments about how they have learned to think differently

about how to manage risk from drought include:

• “Will be able to use data to estimate rainfall in areas of the ranch to decide # of stock to

move and where to move them.”

18

• “Totals don’t show the entire picture where this data can show SPI and where we really

are in a given time for rainfall.”

• “Being able to generate and use reports for planning purposes to stay ahead of poor

conditions.”

• “When planning for the year, could work with data to inform potential water hauling,

etc.”

Finally, 66.7% felt that the information and tools they learned about in the Workshop would be

Greatly useful to other ranchers and land managers; 29.2% Moderately.

IV. Next Steps

Based on discussion at the Workshop and ongoing feedback from users, we are working to fine

tune myRAINgeLog and develop new features, as well as looking for funding to support these

efforts. Planned features include:

• public maps: publicly-viewable map of gauges and their observations

• public gauges: sharing the ability to log observations with other myRAINgeLog users

• historical data chart builder: displaying overlapping years or “seasons” of observations on

the same chart

• cumulative precipitation outcome likelihoods: allows users to anticipate potential climate

outcomes.

On 14 August 2017 we submitted a proposal to the NOAA SARP FY2018 Funding Opportunity

addressing the Coping with Drought Initiative in support of the National Integrated Drought

Information System to continue this work.

V. References Cited

McClaran, M.P. and H.Wei. 2014. Recent drought phase in a 73-year record at two spatial

scales: Implications for livestock production on rangelands in the Southwestern United

States. Agricultural and Forest Meteorology 197:40-51.

Quiring, Steven M. “Monitoring Drought: An Evaluation of Meteorological Drought Indices.”

Geography Compass 3, no. 1 (January 2009): 64–88.

19

Appendix A: Rain Gauge Construction Guide

1 DRAFT – v1.3June2017

Do-it-yourself construction guide: Rugged accumulation precipitation

gauge for remote monitoring

Introduction Precipitation is the key

variable in assessing

drought status and tracking

changes in drought

conditions. Precipitation is

also highly variable in space

and time and having your

own rain gauge ensures

you have data specifically

for your location. Backyard

rain gauges are inexpensive

and easy to use, but what if

your monitoring location is

at a remote, unattended

site? A simple and

inexpensive accumulation

gauge can help in this

situation. These gauges are

typically open containers

like PVC pipes, capped on

one end, containing a small

amount of oil to stop

evaporation. As

precipitation falls into the

gauge it collects below the

thin film of oil and

continues to accumulate

until the gauge is emptied.

This allows a gauge to be

deployed at a remote site

and read many months or even years later.

Accumulation gauges are easy to construct on your own with materials and tools easily available at any

local hardware store. These directions provide guidance on constructing a gauge with some added

features that are particularly useful for remote monitoring (Figure 1). One particular feature of this

gauge is the use of a clear PVC which allows the design to mimic the ease of use of typical plastic

Figure 1. Clear PVC accumulation gauge


backyard gauges, but has the ruggedness to be deployed in remote locations and harsh environments.

This pipe is not as readily available at hardware stores, but available through online retailers.

Before you begin The first decision to make before constructing a gauge or several gauges is deciding how tall it should

be. This largely depends on two factors 1) How often you intend to visit the gauge and empty it, and 2)

how much precipitation typically falls over this period be it a season or a year. An online tool called the

Precipitation Logbook Generator (https://goo.gl/JswZJJ) can help you decide on the height of a gauge

based on the historical climate at that location. Go to ‘Choose Location’ and click on the map where you

intend to install your gauge and then click ‘Download data’. Wait for the data to download and then

proceed to the ‘Generate Logbook’ page. To assess the typical annual amount of precipitation at your

location set Start Month to 1, Start Day to 1 and Chart length to 365 and click Generate Chart. The black

line represents the median accumulation of daily precipitation observed at this location (based on 1981-

2015 PRISM climate data). The chart below lists the values used in the creation of the chart. The last

value in the Normal (50th %) column is the median total precipitation for this location. That means that

half of the years in the historical record were wetter and half were drier than this value. If you want your

gauge to hold a year’s worth of precipitation then choosing a depth greater than the 50th line, but less

than the 98th will ensure you have a good chance of not having your gauge overfill. This chart can also be

used directly as a logbook to track precipitation with your new gauge. Click on the ‘Download’ button

and print out a logbook customized for your site.

Parts needed This gauge design includes the use of standard schedule 40 PVC parts, clear PVC pipe, and the

installation of drainage valve to support ease of use and maintenance in the field. A simpler design

would be to use standard schedule 40 white PVC and no valve. This would require the use of a dipstick

to measure precipitation levels and also would require removing the gauge to empty it. The rest of this

guide has guidance on building and using a clear PVC gauge with valve. The screened cap will work on

any PVC gauge. Also, this design uses 2” PVC pipe and fittings which keep the cost relatively low (larger

pipe and fittings are more expensive). Look for furniture grade or UV resistant clear PVC tubes (see

Appendix A for a list of online retailers). These will last longer in direct sunlight without becoming brittle

and cracking. Narrower pipe sizes can be used (e.g. 1” PVC pipe), but may be more prone to error

caused by wind (see http://www.bom.gov.au/climate/cdo/about/rain-measure.shtml for more

information on tradeoffs with gauge sizes).

http://www.bom.gov.au/climate/cdo/about/rain-measure.shtml


Part Picture Notes

2” clear schedule 40 PVC pipe (often available in 5 and 10 ft sections)

Available online through various retailers. Look for UV resistant or furniture grade for outdoor use. (See Appendix A for a list of online retailers) Cost: ~ $7-8/foot

2” schedule 40 PVC slip cap (1 per gauge)

Available at any hardware or plumbing supply store. Cost: ~ $1

2” schedule 40 PVC coupling (1 per gauge)


1 ¾ to 2 ¾ “ adjustable hose clamps (2 per gauge)

or Larger adjustable clamps that will fit directly around the pipe and post where you are installing the gauge

Available at any hardware or plumbing supply store. Cost: ~ $1-2


Section of metal window screen (at least 4x4” square, 1 piece per gauge)

Available at any hardware or plumbing supply store. Cost: ~ $10/roll

PVC primer and cement (only a small quantity needed for each gauge)


Short piece (at least 2” long) of 2” schedule 40 PVC pipe (1 short 2” section per gauge)

Available at any hardware or plumbing supply store. Cost: ~ $1/foot

¼” Needle drain cock (1 per gauge)



A gauge 2’ high will cost roughly $30 in materials. Some of these materials can be found at reduced cost

online and when purchased in bulk. Several of the parts on the list including the window screen, pipe

tap, sealing tape, and PVC cement can be used to construct many gauges. Most of these parts are also

readily available at hardware stores.

¼” by 18NPT pipe tap

Available at any hardware or plumbing supply store. Size and threading match valve. Cost: ~ $10

Aluminum yardstick ruler (or adhesive ruler, 1 per gauge)

Rulers available at any hardware or plumbing supply store. Adhesive rulers with different scales (metric, 0.1”…) are also available through different online retailers [for example see https://stop-painting.com/) Cost: ~ $5

Thread sealing tape (only short length needed per gauge)


Light, household multi-purpose oil (like 3-1 Oil) or mineral oil. (1 container can be used for multiple gauges). Automatic transmission fluid (ATF) can also be used as an evaporation barrier.



Tools needed Hack saw that can cut PVC and metal ruler

Utility knife (to trim window screen)

Drill and 7/16” drill bit (to drill out drain hole - size depends on tap size; use drill press if

available)

Socket wrench to drive pipe tap

Rubber mallet or hammer (to construct screened cap)

Marker (for marking measurements)

Adjustable Wrench (to tighten drain valve and hose clamps)

WD40 or silicone spray (to construct screened cap)

File or sand paper (to clean off burrs on cut PVC)

Rag for cleaning off tools and parts

Gather parts and tools and find a safe and well ventilated workspace. It will take about one hour to

assemble one gauge.

Instructions 1. Cut PVC pipe to desired length

a. Measure desired length and mark

PVC with marker. Use pipe clamp

make a mark around diameter of

pipe. This will help you make a

square cut.

b. Secure the pipe to a bench using

clamps or bench vise and cut

through the pipe following the

mark you made around the pipe.

Tip: Use two pipe clamps on either

side of the cut line to guide saw to

ensure straight cut

c. Use a file or some sand paper to remove the burrs around the cut.

Step 1a – Mark and cut pipe to length


2. Prepare end cap for drain valve

a. Secure end cap to work bench using clamp or bench

vise or secure to drill press. Drill hole through center

of end cap and clean off burrs with file or sand paper.

b. Keep end cap secured and

place tap into drilled out hole. Start

turning tap by hand and then use

socket wrench to continue turning

tap through hole. Turn all the way

until threads on tap are not visible.

Back out pipe tap and clean away

burrs by hand, making sure not to

damage newly created threads in to

PVC cap.

3. Glue end cap to PVC pipe

a. Clean inside of end cap and

end of PVC tube with a dry, clean rag making sure no burrs or debris are

present where glue will be applied.

b. Dry fit the end cap to the PVC pipe to ensure snug fit. Note how

far end cap covers PVC

tube

c. Apply PVC primer to inside of end cap

(keep away from threads in drain hole)

and to outside end of PVC pipe where

end cap will cover. Then apply PVC

cement to all areas covered in primer.

Slide end cap onto PVC pipe and turn

(quarter turn) to create seal. Allow seal

to cure for 15 minutes.

4. Install drain valve

a. With the valve

pointing down, wrap thread sealing tape counter clockwise 5-7

times around the threads. Keep tape away from bottom valve seat

to prevent interfering with seal. This thick layer of sealing tape will

serve as a gasket when threaded into the gauge.

b. Hand tighten the valve into the drain hole in the end cap. Use a

wrench to tighten further until the valve is fully seated against the

end cap. Be careful not to overtighten with the wrench

(overtightening will damage the plastic threads in the end cap).

Step 2a – Drill out drain

hole

Step 2b – create

threads with tap

Step 3c – Glue end cap to PVC pipe

Step 4a – wrap valve with

thread sealing tape


c. Close valve, hold gauge upright and fill with some water. Check

to see if valve leaks around collar. Carefully tighten until leaking stops.

If leaking does not stop, remove valve and repeat steps with new

thread sealing tape. More tape may be necessary to create tight seal

around valve. Tip: Using thread sealing tape allows you to remove and

replace the valve if necessary. The valve could also be more

permanently installed and sealed using a silicone glue.

5. Build screened cap

a. Take white PVC pipe and measure 1 5/8th “ length. Use pipe

clamps to make a straight line mark around the diameter of the tube.

Cut off piece and remove burrs with file or sand paper.

b. Cut 4” by 4” square out of steel or aluminum window screen.

c. Take PVC coupler and apply a light coating of lubricant like WD-

40 or silicone spray using a rag to the

inside of the coupler.

d. Place square of window screen on

2” coupler, centering over opening.

e. Place short 1.5” PVC section on top of screen and lightly

tap into place with hammer or rubber mallet. This step is

a bit tricky and may require a couple of attempts to seat

the pipe into the coupler. Go slowly to prevent tearing the

screen as the pipe piece is pounded into place.

f. Once the PVC pipe is fully seated, trim excess screen using

utility knife.

g. PVC piece is slightly

longer than coupler and is

intended to stick up slightly

above opening to prevent

rain drops from splashing

into gauge.

6. Secure ruler to gauge

a. Cut ruler to length of exposed PVC on gauge above

glued end cap and just below where screened end cap will

slide on. Use hacksaw for steel ruler cut to appropriate

length

b. Hold cut ruler to side of gauge and slide two pipe

clamps over pipe and ruler. Tighten to secure ruler.

c. Pipe clamps also serve as means to wire gauge to fence posts in field installations.

7. Test gauge for leaks

a. Wrap some baling wire around the pipe clamp to make hook for hanging the gauge.

b. Hang the gauge on a wall in your workshop or on a fence outside, fill the gauge up at

least half way with water and leave to sit for at least an hour. Mark the level of the

water with a piece of tape for reference.

Step 5e – tap PVC section

into coupler

Step 5f – trim excess screen using

utility knife

Step 4b – thread valve

into drain hole and

tighten


c. After sitting for some time, check to see if the water level has dropped below the level

of the tape. Check the gauge for leaks around the glued seam between slip cap and pipe

and also around the valve. If a leak forms around the glued cap, it is best to saw this

section off and start over by gluing a new cap on. If the valve is leaking, remove it and

clean off the existing thread sealing tape. Re-wrap the valve with a thicker layer and

reinstall. Check for leaks again.

Installing gauge 1. Survey intended gauge location and try to find a spot that is relatively open and away from trees

and other overhanging obstructions (like telephone poles and/or wires) that could impact

precipitation accumulations.

2. Affix gauge to fence post or other post by wrapping baling wire first around pipe clamps and

then around post (an oversized clamp around the post and the gauge can also be used to affix

the gauge). Make sure the top of the gauge is higher than the post itself. Installing on the north

side of the post will also offer some protection from direct sunlight. It is important to strongly

affix the gauge to the post if livestock or large wildlife may be present. They may rub against the

gauge and knock it off if not strongly attached.

3. Prime the gauge with some water to bring the level above the bottom of the ruler. Add between

1/8 and ¼” of light machine oil to gauge making sure it covers water surface and creates a

barrier to evaporation. Too thick a layer may hamper rain drops moving through this oil barrier

impacting the accumulation amounts and accuracy of the gauge. Use the valve to empty water

until the bottom of the oil layer reaches zero on the ruler.

4. This is an important time for a final check for leaks around the valve collar, the valve itself and

the glued cap. Carefully tighten valve if necessary.

Other installation

considerations Although rain gauges are

typically in open areas that

are visible from long

distances, this also creates

the potential for vandalism

in highly trafficked areas.

Steps to reduce the

potential of vandalism

include camouflage by

painting white caps darker

colors and even the pipe

itself if a narrow site window is preserved (add a strip of masking tape from top to bottom of gauge

before painting), or cloaking them with burlap or other camouflaging material. Also consider placing a

label on the gauge explaining what it is for and your contact information. Research in Germany found

that a personal, friendly and descriptive label reduced the rate of vandalism and theft of unattended

Add water Add Oil Drain to zero level

Installing gauge step 3 – Priming gauge


monitoring equipment (Clarin, B.-M., E. Bitzilekis, B. M. Siemers, and H. R. Goerlitz, 2014: Personal

messages reduce vandalism and theft of unattended scientific equipment. Methods Ecol Evol, 5, 125–

131, doi:10.1111/2041-210X.12132.).

Anti-freeze is often added to accumulation gauges like these

to protect against cracking and splitting. This is only a risk in

very cold locations where water in the gauge may freeze

solid. In most instances, newer PVC pipe is strong enough to

withstand the expansion of water when it freezes, forcing

the ice to expand up the inside of the pipe. Older gauges that

have been exposed to the sun for many years may weaken

and be more prone to splitting and cracking when freezing. If

you forgo using antifreeze you can still take a measurement

from a frozen gauge. Water expands about 9% in volume when freezing, so multiplying the reading of a

frozen gauge by 0.91 will provide a rough estimate of the equivalent liquid level. If the gauge is full of

snow, then it is necessary to wait until all of the frozen precipitation melts to get an accurate

precipitation reading.

If you use antifreeze to protect your gauge try and use a non-toxic formulation. Antifreeze formulations

containing ethylene glycol are toxic and can be harmful to animals and wildlife if the gauge leaks or is

tipped over and emptied on the ground. Antifreeze containing propylene glycol which is non-toxic and

biodegradable can be found auto parts and hardware stores. A concentrated form (look for 100% and

not pre-mixed 50/50 formulations) of this type of antifreeze can be used to charge the gauge and will

help prevent freezing. Consider resetting and charging the gauge in the fall with antifreeze before the

winter season. The antifreeze will dilute as precipitation accumulates in the gauge, but should still be

concentrated enough to protect from freezing. The amount of antifreeze ultimately needed will be a

function of how much precipitation is expected during the winter season and how cold the

temperatures may ultimately reach.

Using the gauge No rain gauge is perfect and this gauge design is no exception. All rain gauges are prone to error which is

typically expressed in lower than actually occurring total precipitation amounts. Some sources of error

included (Brock and Richardson, 2001: Meteorological Measurement Systems. Oxford University Press,

New York, 290 p.):

Wind: Wind can cause ‘undercatch’ where drops are blown across the opening of the gauge

erratically during precipitation events.

Splash out: Large drops can strike the top of the cap and splash out rather than in. The slightly

raised PVC collar on the screened cap is designed to minimize this impact.

Wetting and Evaporation: Drops from light precipitation events can be caught up in the screen

in the cap and along the sides of the gauge. If these drops don’t accumulate below the oil layer,

they will most likely evaporate in between rain events and won’t contribute to the total. Adding

a simple plastic funnel to the top of the gauge below the cap can help guide drops away from

Rain gauge for range monitoring

please do not disturb – Please

contact me if you have any questions

and would like to know more:

Name/phone number

Example rain gauge label


the sides, improving the collection of the rain water. See Appendix B for instructions on how to

build a funnel for a 2 inch PVC gauge.

Snow: Snow and its liquid water contribution to running precipitation totals is notoriously

difficult to measure. Removing the screened cap in the winter will allow some but most likely

not all snow to accumulate in the gauge. This snow will eventually melt and accumulate below

the oil layer, but will most likely be only fraction of the total snow that fell over the

measurement period. (Note: A frozen gauge will read higher than the liquid amount, wait until

the gauge is completely thawed to get an accurate reading)

Even with these potential sources of error the precipitation data afforded by these gauges provide a

better representation of the local site than estimates based on gauges located some distance away.

Logging observations Reading this clear PVC accumulation gauge is simple, just note the level of the water at the bottom of

the oil layer when visiting the gauge. Note this observation in a field book with date and any other

observations of field conditions that may be useful in interpreting this precipitation amount at a later

time. The observation that you log will grow over time until the gauge is reset by emptying it to a zero

level. Subtract subsequent observations from each other to get the total precipitation that occurred

between the observation dates. More frequent observations will give you more insight into the timing

and frequency of precipitation events. Set up a schedule to visit gauges and log observations that

matches key decision points in your management schedule (e.g. grazing rotations, water availability in

tanks…).

Several tools exist to help manage accumulation gauge type data.

The Precipitation Logbook Generator (https://goo.gl/JswZJJ) allows you to create a printable

logbook with reference climate information for any gauge location in the continental U.S.

The myRAINge web application (https://myraingelog.arizona.edu) allows you to manage data for

multiple gauges in the field with reference climate information, precipitation alerts, and summary

tools.

Maintenance The materials used in these gauges are very durable and should last many years, but they may require

some maintenance from time to time. In particular, having spare parts to repair damage that may occur

from vandalism or wear and tear is a good idea when visiting a gauge. Some spare parts to have on

hand include:

Thread sealing tape and spare valve in case the existing one is leaking; silicone grease in case

valve is sticky

Spare screened cap (built earlier) if the existing one is missing or damaged

Replacement ruler in case existing one is damaged

Baling wire to reattach gauge if it is has fallen off post

Water (and/or antifreeze) and oil to reset a gauge

https://goo.gl/JswZJJ

https://myraingelog.arizona.edu/


The clear PVC tube may need to be cleaned out after several years if it is difficult to read. A long handled

brush and some soapy water will clean out the inside of the tube. Bring additional baling wire as well to

reattach the gauge if removed.

Authors: Michael Crimmins, Mitchel McClaran, Julie Brugger, Ashley Hall, Douglas Tolleson

Contributors: Rangeland Precipitation Monitoring Working Group consisting of members of the Gila

County Cattle Growers Association, ranchers with permits on the Tonto National Forest and staff with

the U.S. Forest Service-Tonto National Forest.

Acknowledgements: Special thanks to D. Crimmins for help in constructing rain gauges, T. Crimmins for

photographing steps in construction process and B. Benne, R. Tanner, and M. Hemovich for providing

initial project ideas and guidance and K. Wolff-Krauter for providing feedback and testing of initial gauge

design. Funding provided by Western Extension Risk Management Education program.

Questions or comments? Contact: Mike Crimmins Associate Professor & Extension Specialist - Climate Science Department of Soil, Water, & Environmental Science The University of Arizona [email protected] ph (520)626-4244 fax (520)621-1647

Appendix A: Clear PVC Suppliers Clear PVC pipes are not readily available at most hardware or plumbing stores. They can be found online

through different distributors. Look for schedule 40 pipe dimensions to ensure that standard PVC fittings

will work and ‘furniture grade’ or ‘UV resistant’ to ensure it is durable for outdoor use. A web search will

yield many different distributors including:

https://www.clearpvcpipe.com/

http://www.usplastic.com/

https://flexpvc.com/

https://formufit.com/

Appendix B: Do-it-yourself plastic funnel for 2” PVC Rain Gauge

A small plastic funnel that fits inside the PVC gauge underneath the cap can be made using a thin, flexible sheet of plastic and the template below. This funnel will help guide drops to the bottom of the gauge below the thin oil evaporation barrier, helping to minimize evaporative losses that occur when drops stick to the side of the gauge. Overall, this should help improve the accuracy of your gauge by capturing more rain drops falling during precipitation events.

Materials needed: printer, thin sheet of plastic (plastic poster board from craft store, plastic folder from office supply store, plastic milk jug…), hard stock cardboard like from cereal box, and strong adhesive like Krazy Glue.

Instructions:

1. Print out this page at full size and cut out template below 2. Glue the template to a piece of hard stock cardboard and trim to edge of template. This will create firm template you can trace around. 3. Place the template on the plastic sheet, trace and cut out. Mark line B on the plastic piece. 4. Roll the cut out plastic piece into a funnel by aligning line A with line B (on template below). Glue the ends in place by placing a thin bead of adhesive down the length of the overlapping ‘glue here’ area. 5. Let the glue set and the funnel is ready to be placed in the

gauge. Plastic will break down over time, periodically inspect the funnel and replace when necessary.

This template will create a 2” deep funnel that is 2-1/8th “ wide at the top with a ¼” opening at

the bottom. Template was generated http://www.blocklayer.com/cone-patternseng.aspx

AB

20

Appendix B: Precipitation Monitoring Best Practices Guide

1 DRAFT – v1.1-May2017

Rain Gauges for Range Management: Precipitation Monitoring Best

Practices Guide

Introduction Precipitation in the form of rain and snow is critical to many aspects of working lands from controlling

the growth of vegetation used in grazing by livestock and wildlife to recharging local water resources

found in springs, tanks and riparian areas. Land management decisions often require some knowledge of

how much precipitation fell within a management unit to assess how past actions have performed and

what to do next. For example, do forage conditions reflect a lack of precipitation or grazing

management? Did the next pasture or allotment in my rotation get any rainfall over the past season?

Given that precipitation monitoring is important, where and how do we usually get this information?

Typically, we consult websites and maps that track precipitation observations from airports and

backyard observers. These ‘official’ sites managed by volunteer and federal agency programs do a good

job of maintaining a steady stream of high quality data, but often are located near cities away from rural

and backcountry areas where the bulk of land management activities occur. Estimates provided by

‘interpolating’ between these official gauges can provide just that, estimates. Knowing how much and

when precipitation fell in your pasture, allotment or land management unit is a key variable for sound

decision making and requires collecting precipitation data directly at that site.

This guide will also highlight some new tools that help put your precipitation observations into a longer-

term climatological context. Knowing how much it rained is one thing, but knowing that observation is

below average for that location and time period is additional insight critical to interpreting and using

that piece of information to support a management decision.

Overall, this “best practices” guide will cover some of the basic approaches to collecting and using

precipitation observations at remote sites in support of rangeland management including:

Tying observations to a drought plan

Where to place gauges and how often to record observations

Managing and using precipitation observations

Rain gauges Precipitation monitoring is one of the most straightforward aspects of weather and climate monitoring

and does not require overly sophisticated or expensive equipment. Simple rain gauges consisting of a

collection container suffice under most situations. Gauges made out of PVC tubes capped at one end

and mounted to fence posts in key areas have been utilized by ranchers and land managers for many

years. These gauges typically have a small amount of oil in the gauge to stop evaporation and are read

several times throughout the year in concert with key land management decision points on the

calendar. Some innovations on this PVC design have been developed including the use of clear PVC that

allows for direct reading of the precipitation amounts in the gauge and a drainage valve that simplifies

resetting the gauge each season [example in figure 1; see companion bulletin titled How to construct a

rugged accumulation precipitation gauge for remote monitoring].


More sophisticated precipitation monitoring approaches exist like using tipping bucket rain gauges with

electronic dataloggers, but bring with them some tradeoffs when compared to simpler methods. Tipping

bucket gauges can collect high resolution information

on the timing and intensity of precipitation, but are

expensive and can fail due to technical glitches or

battery issues in remote locations. The added

information on timing and intensity of precipitation is

only useful if management actions can be tied to these

data. Tipping buckets should be deployed with simple

backup gauges anyway to ensure that data on total

precipitation is collected in the event that a

dataloggers fails.

Developing a precipitation monitoring plan Knowing how many gauges you need and where to

place them requires some thought on the types of

management decisions you have to make (e.g. grazing

rotations, anticipating impacts to water sources) and

the geography of your operation. The number of

gauges and how often you read them and use their

data will be an optimization of time and resources

relative to your operation. More gauges, read more

frequently will clearly provide more information on

precipitation across your management area, but this

should match your management plan. For example, if

you had grazing rotation that cycled through three

pastures over the course of a year you could first assess how many rain gauges would be required to

adequately capture the variability for those pastures. If the pastures were relatively small, one gauge in

an open easily accessible area per pasture may suffice. If the pastures are large with large amounts of

topographic relief, more gauges may be required (e.g. one for higher elevation area of the pasture and

one for lower areas). Through your pasture rotation calendar, you could first read the gauge or gauges in

your current pasture, then the next pasture in your rotation to anticipate how forage conditions may

develop there. The final pasture could be read last to plan for conditions the following year or to assess

if it could be used in a contingency drought situation. Collecting information on forage conditions and

water sources with notes and photo points is also critical at each gauge reading to make use of the

precipitation data over time.

More gauges is better than fewer (or can’t hurt) Tying gauge locations and a schedule for reading them directly into management plans is the best

approach for making precipitation data useful (for example drought contingency plans – see University

of Arizona extension bulletin

https://extension.arizona.edu/sites/extension.arizona.edu/files/pubs/az1725-2017.pdf). Any approach,

though, that facilitates the collection of observations at remote areas that can be used to support

decision making is worth considering. Rugged, remote rain gauges that have an oil barrier to stop

Figure 1. Clear PVC rain gauge (photo

courtesy of J. Lyman)

https://extension.arizona.edu/sites/extension.arizona.edu/files/pubs/az1725-2017.pdf


evaporation are relatively inexpensive, require little maintenance and can be read infrequently making

them ideal for deployment at numerous locations. Some strategies to consider include:

Collect data at house, ranch headquarters, or ranger station – frequent observations at these

locations can provide good reference points from which to compare readings made at remote

gauges.

Place gauges in locations you drive by often – gauges that are readily accessible for quick visits

near roads that allow for more frequent observations. Mounting gauges on fence posts near

gates may even allow for ‘drive thru’ readings. These may be close enough to other key

monitoring areas to provide useful information in interpreting local conditions.

Use topography as a guide – higher elevation areas typically get more precipitation than lower

elevation areas, so capturing observations at the highest and lowest points of your management

area can often give you an indication of the range of precipitation that occurred over the area. A

couple of gauges in middle elevation areas can also serve as a check on this logic.

No such thing as ‘too many gauges’ – since PVC gauges are inexpensive to build and require little

maintenance there is no harm in placing gauges in locations where you don’t immediately need

the information, but may need it at some point in the future. If a gauge is sufficiently tall given

the precipitation that typically occurs at that location, it can continue to collect cumulative

precipitation for seasons to years. This type of monitoring could be useful at especially remote

sites that are visited every couple of years to assess longer term changes.

Managing and using precipitation data A key part of your precipitation monitoring plan is developing a way to log and interpret your

observations. Ideally, the precipitation values you observe at each gauge will help guide a specific

decision or management action. This requires tying different precipitation levels to specific time periods

and decisions. For example, a ranching drought contingency plan can be set up to trigger different

management actions when a location reaches different levels of drought intensity at different times of

the year (see University of Arizona Extension Bulletin

https://extension.arizona.edu/sites/extension.arizona.edu/files/pubs/az1725-2017.pdf). This requires

being able to put your precipitation observations into some kind of long-term, climatological context. If

you have a long-term set of observations (at least 10 years, but longer is better) at your rain gauge you

can get a sense of whether or not the values are unusually wet or dry for the time of year at that

location. Two new tools exist specifically for helping with tracking accumulated precipitation at new and

existing gauges and providing climatological context for the observations:

The Precipitation Logbook Generator (https://goo.gl/JswZJJ) allows you to create a printable

logbook with reference climate information for any gauge location in the continental U.S. (See

appendix A with guidance on how to use the Logbook generator)

The myRAINge Log web application (https://myraingelog.arizona.edu) allows you to manage

data for multiple gauges in the field with reference climate information, precipitation alerts, and

summary tools.

https://extension.arizona.edu/sites/extension.arizona.edu/files/pubs/az1725-2017.pdf

https://goo.gl/JswZJJ

https://myraingelog.arizona.edu/


Both of these tools rely on using historical gridded climate data to generate reference climate statistics

for a specified location. Figure 2 shows an example cumulative precipitation chart generated for a

location in Arizona using the Precipitation Logbook Generator. The chart was customized to track

precipitation for the summer monsoon season from June 15th to September 30th. The smooth curves

(dashed and solid black lines) were generated from 35 individual seasonal cumulative precipitation

estimates for that location (1981-2015 time period). The curves represent how common or rare a

particular cumulative precipitation total is relative to these historical estimates. The solid black line that

runs through the middle of all of the curves is the median or 50th percentile value and is the most

frequently observed cumulative value through the season. The other lines include:

2nd percentile: Very dry conditions with only 2% of historical values at or below this precipitation

depth; roughly corresponds to 2 standard deviations below average in a normal distribution.

Figure 2. Example cumulative precipitation reference climatology chart with observations plotted.

6.74”

4.13”

0”

3.75”

5.97”

Smooth curves

generated from daily,

historical gridded

climate data statistics

Irregular, actual rain

gauge readings

logged by observer


16th percentile: Dry conditions with 16% of

historical values at or below this precipitation

depth; roughly corresponds to 1 standard

deviation below average in a normal distribution.

84th percentile: Wet conditions with 84% of

historical values below this precipitation depth;

roughly corresponds to 1 standard deviation

above average in a normal distribution.

98th percentile: Very wet conditions with 98% of

historical values below this precipitation depth

(inversely, only 2% of observations greater than

this value); roughly corresponds to 2 standard

deviations above average in a normal distribution.

The red line on the chart in Figure 2 provides an example

of how actual observations could be entered and

interpreted. In this example, the gauge is a typical PVC

type gauge at a remote site with an oil evaporation barrier allowing precipitation to accumulate over

time. The gauge is empty at the beginning of the monsoon season on June 15th. The first observation is

made on July 12th and the gauge is still empty. The black line (median/50th percentile) indicates that this

location typically receives 1” of cumulative precipitation between June 15th and the first observation

date of July 12th. The zero inch observation falls on the 2nd percentile indicating that the site is very dry

and rarely so for that date. It is early in the season, but this very dry observation could trigger a

management action depending on the site and the objective.

The next observation is made on August 2nd and the gauge total has risen to 3.75”. On the chart, this

cumulative total is now above the 84th percentile or into the ‘very wet’ part of the historical distribution.

This quick turnaround from dry to wet is not uncommon in Arizona during the summer monsoon season

where a handful (or even one) thunderstorm can drop several inches of rain. Another observation was

made on August 16th with a value of 4.13”. This value was now slightly below the 84th percentile, but still

above the median cumulative value for this time of year. The final two observations of 5.97” on August

31st and 6.74” on September 30th both fell between the 50th and 84th percentiles, indicating that

cumulative precipitation kept pace ahead of the long-term median values and were wetter than

historical values through the end of the season. The relatively frequent observations, every couple of

weeks, help detect some subtle shifts in the timing of precipitation throughout the season. Reading the

gauge once in the season at the end of the September would have missed the potential impact of the

early season dry spell on subsequent range conditions and water resources.

Cumulative precipitation is a bit

different than the way we typically

see precipitation represented in

discrete daily, monthly or seasonal

totals on maps and charts. This is the

running total from some start date,

consistent with the way precipitation

accumulates in a PVC gauge over

time. You can check the depth of

water in the PVC gauge at various

times over a season and this value

will represent the cumulative

precipitation total until you empty

the gauge.


Figure 3, shows an example with the exact seasonal total, but different sequence of rain events with the

bulk of total precipitation coming later in the season. Very dry conditions prevailed right up until

September where precipitation totals quickly rose to an above median seasonal total by the end of the

month. This location was dry for most of the summer and presumably suffered significant drought

impacts due to this pattern precipitation over the summer season. The frequent observations through

the summer help capture this pattern and also help decipher why this location might be showing

drought impacts even though the seasonal total is near what is expected for this time of year.

Checking a gauge more frequently and plotting these observations on a chart like the ones in Figures 1

and 2 can provide more insight into the timing, intensity and frequency of precipitation events

throughout a season. This can help provide insight into, for example, why rangeland conditions don’t

readily reflect the seasonal total captured in a gauge. It could be that all of the rainfall came in a handful

of events at the end of the season which would cover up the fact that soil moisture levels were actually

very poor throughout the early part of the season. This can be challenging and cost and time prohibitive,

though, to do at very remote sites, so tying when and how often to check a gauge to the timing of

specific management actions can help in developing an observation schedule.

Figure 3. Example cumulative precipitation reference climatology chart with different set of

precipitation observations plotted.

6.74”

0”

4.25”

1.5”

2.1”


Putting it all together: Connecting decisions with precipitation observations Having a seasonal precipitation reference climatology chart like the ones in figures 2 and 3 could help

support developing a decision calendar which would help you decide when to check precipitation

observations at different management areas and what to do if the observation represents drier or

wetter conditions than would be expected for that date and location. Take figure 4 as an example which

represents the summer monsoon season (June through September) precipitation at a location in

Arizona. This season provides critical precipitation to support summer forage production and subtle

shifts in timing, intensity and rain event frequency can impact that production in subtle ways. The figure

shows a precipitation monitoring plan with three observation points through the summer to:

1) anticipate the timing of forage “green up” in the current or next pasture in a rotation

2) assess ‘near peak’ forage production to assess whether or not adjustments to the rotation

schedule are necessary

3) final check of conditions at the end of the season to assess total precipitation amounts and the

carry over in production that will be available for subsequent seasons.

Figure 4: Example of likely decision points regarding livestock management over the course of a

summer monsoon season.


In this example, based on prior experience and ability to check gauges throughout the season three

dates were settled on for this plan. The first check at July 20th indicated that no precipitation had fallen

yet at this location which is unusual given the precipitation climatology curves on the chart. Zero

precipitation at this date is near record dry for this location falling below the 2nd percentile curve. This

may indicate that a substantial delay in green up will occur and may require delaying moving the herd

into this pasture if forage “green up” was expected before entry.

The second observation point in this plan occurred on August 23rd, near the middle of the summer

monsoon growing season with the expectation that ‘near peak’ forage conditions would be occurring

depending on rainfall up to this point. The observed precipitation was 3 inches at this point and just

below the median expected cumulative precipitation for this date or slightly drier than expected. Forage

conditions may be lagging behind expectations as well given this amount of precipitation. This mid-

season observation can serve to assess how long you can stay in this pasture and whether or not any

course corrections need to be made to the grazing schedule going forward.

The final observation made at the end of the season on September 30th, served as a wrap up assessment

of total precipitation and conditions at the site. The observation of 6.74” was just above the long-term

median value and would suggest site conditions would be near average as well.

The observations made at the beginning of the season with the late start, slightly dry conditions at the

midpoint and the final near median observation probably tell a richer story together than the just the

final observation alone. Overall production at the site may be less than expected given the late start and

mediocre precipitation in the middle of the season, even though the final total is near median. The final

observation also gives you a chance to assess how much carryover forage will be available in subsequent

seasons allowing for moving directly into the next seasons plan. This type of monitoring plan can be

made for any season or for the whole 12 months seasonal cycle if that makes more sense for your

operation.

Collecting additional, supporting observations Precipitation observations, even with climatological context, only provide part of the story when

determining a management decision. When visiting a gauge, consider collecting additional observations

of range and forage conditions, spring or water tank levels if nearby and any other observations that will

help you interpret your precipitation values. These observations can be entered on your Precipitation

Logbook sheet or in your myRAINge account or just jotted down in a field book. Also note if you took

any management actions at that time based on your observations. Over time, these observations will

grow into a valuable site specific dataset that will help tune up your management toolbox associated

with different precipitation observations.

Another valuable way of collecting these types of observations is by taking photos of the site when

visiting your gauge. Taking four photos in each cardinal direction (N-S-E-W) with the gauge in the

foreground provides a comprehensive view of the local site conditions. Here are several links to

additional resources on rangeland photopoint monitoring:

Using Repeat Color Photography as a Tool to Monitor Rangelands (L. Howery and P. Sundt,

1998) https://extension.arizona.edu/sites/extension.arizona.edu/files/pubs/az1024-2016_0.pdf

https://extension.arizona.edu/sites/extension.arizona.edu/files/pubs/az1024-2016_0.pdf


Fast and easy rangeland monitoring using repeat photography (F. Mashiri, 2015)

http://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=16616

Photo Monitoring for Ranchers Technical Guide (A. Gearhart and K. Launchbaugh, 2015)

https://catalog.extension.oregonstate.edu/pnw671

Authors: Michael Crimmins, Mitchel McClaran, Julie Brugger, Ashley Hall, Doug Tolleson, Andrew

Brischke

Contributors: Rangeland Precipitation Monitoring Working Group consisting of members of the Gila

County Cattle Growers Association, ranchers with permits on the Tonto National Forest and staff with

the U.S. Forest Service-Tonto National Forest.

Acknowledgements: Special thanks to B. Benne, R. Tanner, and M. Hemovich for providing initial project

ideas and guidance. Funding provided by Western Extension Risk Management Education program.

Questions or comments? Contact: Mike Crimmins Associate Professor & Extension Specialist - Climate Science Department of Soil, Water, & Environmental Science The University of Arizona [email protected] ph (520)626-4244 fax (520)621-1647

http://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=16616

10 DRAFT – v1.1-May2017

Appendix A: Precipitation Logbook Generator The Precipitation Logbook Generator is an online tool that creates a reference precipitation climatology

for any location by leveraging a spatially continuous, gridded, long-term dataset of daily precipitation

estimates for all locations in the continental United States. Choose a location and generate a custom

logbook by following these steps:

1. Click on the 'Choose a location' tab at the top of the page. Pan and zoom to your location of interest

and click on the map. Click on 'Download Data' to load historical climate data into tool.

2. Click on the 'Generate Logbook'

tab at the top of the page.

Customize the format of your

reference chart and table by

selecting the beginning month

and day and length in days of the

summary. Enter a description of

the site or gauge name for

reference. Click on the 'Generate

Chart' button to generate the

custom chart and table in the

right panel. Repeat steps on this

page to make any adjustments on

beginning date and/or summary

length.

3. The reference table and chart can

be printed directly from this page.

A printable version can be also be

generated by clicking on 'Download' button. This will prompt your browser to save an html file

locally which can be opened and printed by a browser as well. Repeat steps 1 through 3 to generate

additional charts and tables of other locations.

More information on how use the tool and interpret charts can be found at:

https://uaclimateextension.shinyapps.io/precipChart/

Example chart with local observations added

21

Appendix C: Workshop Agendas

Developing tools for monitoring precipitation and supporting ranch-scale

drought detection Workshop 1: June 30th, 2016 – 8 to 1pm

Mazatzal Hotel and Casino

Highway 87, Mile Marker 251

Payson, AZ 85541

Time Topic/Activity

8-8:30 am Registration

8:30-9 am Introductions

9-9:45 am Presentation: Basics of precipitation monitoring

9:45-10 am Break

10-11 am Group discussion: Needs, approaches, and best practices

for precipitation monitoring

11-11:30 am Overview of prototype rain gauges and online tool

11:30-12pm Workshop wrap up – discuss format and timing of next

workshop, final questions

12-1pm Lunch and Monsoon Season Climate Outlook

1-2pm Optional: Hands on training with online tools and

prototype rain gauges

Developing tools for monitoring precipitation and supporting ranch-scale

drought detection Workshop 2: November 2nd, 2016 – 9 to 2pm

Mazatzal Hotel and Casino

Highway 87, Mile Marker 251

Payson, AZ 85541

Time Topic/Activity

8:30-9 am Registration (coffee provided)

9-9:30 am Introductions – best weather story of the summer

9:30-10 am Recap of last workshop and project update

10-11:30 am Group Discussion: 2016 Summer Monsoon Season Precip

Monitoring Debrief

11:30-12 pm Group discussion: myRAINge Log Web Tool Design

12-12:30 pm Lunch

12:30-1pm Group discussion: Development of ‘best practices’, using

data

22

1-1:30pm Project deliverables and structure for workshop #3

1:30-2pm Wrap up and Evaluation

Rangeland Precipitation Monitoring Workshop June 15, 2017 – 9:00am - 2:30pm

(Check-in begins at 8:30am) Bullion Plaza Cultural Center

150 N Plaza Circle Miami, Arizona 85539-1629

Time Topic/Activity

8:30-9 am Registration

9-10 am Workshop and project Overview

10-10:15am Break

10:15-11 am Rangeland Precipitation Monitoring Best Practices and

Applications

11:00-12:00 pm Do-it-yourself Rain Gauge Construction Guide

12:00-1:00 pm Lunch

1-2 pm Introduction to myRAINge Log – online precipitation

data management tool

2-2:30 pm Next steps, wrap up and evaluation

2:30-3:30 pm Post workshop hands on session with gauges and tools

23

Appendix D: Rangeland Precipitation Monitoring Workshop Report Evaluations

Rangeland Precipitation Monitoring Workshop Evaluations Summary

15 June, 2017, Miami, AZ N = 24

1. Overall, how valuable was this Workshop?

2. What is your opinion of the design of the rain gauge?

3. How likely are you to use one of the rain gauges introduced in the Workshop?

4. How likely are you to build you own rain gauges that use this design?

5. How much did the Workshop increase your understanding of best practices for ranch-scale

precipitation monitoring?

6. How much did the Workshop increase your understanding of how to analyze and interpret

precipitation data you have collected?

Greatly

19 (79.2%)

Moderately

5 (20.8%) Minimally Not at all Undecided

Very

favorable

19 (79.2%)

Somewhat

favorable

4 (16.7%)

Unfavorable Very

unfavorable

Undecided

1 (4.2%)

Very likely

21 (87.5%)

Somewhat

likely

2 (8.3%)

Unlikely

1 (4.2%) Very unlikely Undecided

Very likely

10 (41.7%)

Somewhat

likely

12 (50.0%)

Unlikely

1 (4.2%) Very unlikely Undecided

Greatly

13 (54.2%)

Moderately

8 (33.3%)

Minimally

3 (12.5%) Not at all Undecided

Greatly

11 (45.8%)

Moderately

13 (54.2%) Minimally Not at all Undecided

24

7. How likely are you to use myRAINgeLog to archive and interpret your precipitation records?

8. How much did the Workshop increase your understanding of how precipitation data can be

used for livestock management decision making?

9. How likely are you to use this information to plan pasture rotations and interpret your

vegetation monitoring data?

10. How much has the information from this Workshop helped you think differently about how

to manage your risk from drought?

11. Thinking more broadly, how useful will the information and tools you learned about in the

Workshop be to other ranchers and land managers?

12. Any additional comments?

Very likely

17 (70.8%)

Somewhat

likely

4 (16.7%)

Unlikely

2 (8.3%) Very unlikely

Undecided

1 (4.2%)

Greatly

6 (25.0%)

Moderately

16 (66.7%)

Minimally

1 (4.2%)

Not at all

1 (4.2%) Undecided

Very likely

7 (29.2%)

Somewhat

likely

15 (62.5%)

Unlikely Very unlikely Undecided

2 (8.3%)

Greatly

5 (20.8%)

Moderately

18 (75.0%) Minimally Not at all

Undecided

1 (4.2%)

Greatly

16 (66.7%)

Moderately

7 (29.2%) Minimally Not at all

Undecided

1 (4.2%)

Rangeland Precipitation Monitoring Workshop Report 15 June ... · Michael A. Crimmins, Mitchel P....

Documents

Transcript of Rangeland Precipitation Monitoring Workshop Report 15 June ... · Michael A. Crimmins, Mitchel P....