This report, funded by The Nature Conservancy, distills insights gained from several years of pilot projects, studies and experiences related to strategic agricultural water conservation for water security purposes.
Insights Gained on Agricultural Water Conservation for Water Security in the Upper Colorado River Basin - Full report
Resources included in the report, by topic, with links
System Conservation Pilot Program Reports
The Upper Colorado River Commission reports on the SCPP (UCRC Staff, Wilson Water Group, 2018) contain a detailed description of how SCPP operated and lessons learned, including the factors affecting potential cooperators’ interest and ability to participate in the program.
The Bureau of Reclamation conducted its own review of the SCPP (Reclamation, 2021), with a section focused on the Upper Basin program. The report also includes detailed background information and information on the Lower Basin SCPP.
Grand Valley, CO Conserved Consumptive Use Pilots
The Grand Valley Water Users Association participated in the SCPP and conducted an extensive review of the project (J-U-B Engineers and Grand Valley Water Users Association, 2019), including surveying participants afterwards.
Colorado: West Slope Perceptions
In 2019, Kelsea MacIlroy explored socio-cultural perceptions of issues related to Demand Management on Colorado’s Western Slope (MacIlroy, 2019).
In 2021, the Colorado River District released a report from a stakeholder advisory committee it established on Demand Management (Colorado River District, 2021).
Tools for Protecting Agricultural Water Rights While Enabling Temporary Transfers
Tools for protecting agricultural water rights while enabling temporary transfers for other purposes include:
- Utah’s Water Banking Pilot Program: https://utahwaterbank.org/ .
- Utah’s new Instream Flow legislation: https://le.utah.gov/~2022/bills/static/HB0033.html
- Various tools in Colorado outlined in a white paper by the Colorado Water Trust(Colorado Water Trust , 2020): Colorado Water Trust
- Alternative Transfer Methods in Colorado: https://cwcb.colorado.gov/focus-areas/supply/water-sharing-agreements
- New Mexico’s Active Water Resource Management options, including shortage sharing agreements and water banking: https://www.ose.state.nm.us/AWRM/Options.php
Literature Review
A literature review of agronomic impacts of reduced irrigation in the Upper Colorado River Basin conducted in 2019 by Culp & Kelly (Culp & Kelly, 2019) reviewed impacts to a wide variety of crops from different degrees of deficit irrigation.
Colorado West Slope Water Bank Studies
A study of the impacts of full and partial curtailment of irrigation on grass and alfalfa fields on Colorado’s West Slope for the Colorado River Water Bank Work Group (Jones, 2015) found that for grass hay, the year after fallowing, fields still produced only 49% of the volume produced on the fields that had not been fallowed, but had fully recovered by the second year after fallowing.
A separate paper on the same project found that alfalfa yields generally improved in a fully-irrigated year following a year of stress due to deficit irrigation (Cabot, Brummer, Gautam, Jones, & Hansen, 2017).
Grand County, CO Project
The “Evaluating Conserved Consumptive Use in the Upper Colorado” project in Colorado’s Grand County, which began in 2020 and will continue through 2023, is assessing the recovery of high elevation grasses following a year of fallowing. Preliminary reports indicate that the grasses recovered completely in the first year after fallowing.
Grand Valley, CO SCPP Project
Participants in the Grand Valley Conserved Consumptive Use Project reported that returning fields to full irrigation after a period of fallowing was challenging (J-U-B Engineers and Grand Valley Water Users Association, 2019).
OpenET
The OpenET platform provides easily accessible estimates of evapo-transpiration from satellite data.
Grand County, CO Project
The “Evaluating Conserved Consumptive Use in the Upper Colorado” project in Grand County, CO is, in addition to assessing forage recovery after fallowing, comparing different methods of consumptive use estimation on normally irrigated, partially irrigated and fallowed high-elevation hay meadows. The 2021 interim report on the project (Cabot, Derwingson, & Torres-Rua, 2021) found that estimates of consumptive use generated by remote sensing using the Open ET platform were very close to estimates generated using ground-based eddy covariance instrumentation, indicating that remote sensing is a scalable and transferrable tool.
Colorado’s Lease-fallow Tool
Colorado’s Lease-fallow tool was developed to simplify and streamline the evaluation of historical consumptive use, depletions, and return flows from irrigation.
Wyoming Experience with Remote Sensing
Wyoming has used the METRIC remote sensing model developed by the University of Idaho for a number of years to get a better understanding of consumptive use (Wyoming State Engineer, 2020).
Utah Review of Depletion Accounting Methods
Utah’s Agricultural Optimization Task Force sponsored a review of potential agricultural depletion accounting methods that was completed in June 2020 (Jacobs, 2020). The report was based on discussions among a panel of experts and compared the strengths and weaknesses of different ground-based and remote sensing methods for estimating consumptive use, recommending different methods for different purposes. The report noted the advantages of remote sensing methods for providing basin-wide estimates of consumptive use, as well as for providing a low-cost alternative for individual water users to using ground-based methods. The report recommended that the state begin by using the well-established METRIC model while comparing its results with other models also available on the Open ET platform. The report recommended a Case Study to validate its recommendations, which is due to be completed in 2022.
According to the Task Force’s 2021 Annual Report, preliminary results from the case study indicate that water depletion accounting is feasible in Utah (Utah Department of Natural Resources, 2021).
Tomichi Creek Water Conservation Project
A project on Tomichi Creek in the Upper Gunnison Basin paid irrigators to stop irrigating early in 2018 and measured the impacts on streamflows. The final report on the project (Kruthaupt, 2019) noted the impact of the timing of haying on CU for a partial season curtailment of irrigation, as well as some discrepancies between remotely sensed ET and more localized measurement.
Existing Tools for Acquisition and Shepherding of Strategically Conserved Water for other Purposes
New Mexico’s Strategic Water Reserve Program allows the New Mexico Interstate Stream Commission to acquire water rights by purchase, lease or donation in order to comply with interstate obligations or benefit threatened and endangered species.
Utah’s Water Banking Pilot Program allows for water rights to be placed in a bank for temporary, voluntary and locally directed water leasing.
Utah’s legislature passed new instream flow legislation in 2022 (HB 33) that enables water right holders to permanently or temporarily dedicate water rights for instream flow purposes, specifying where the water will be used.
Colorado water laws enabling “Alternative Transfer Methods,” or temporary water transfers, are summarized in a report from the Environmental Defense Fund (Environmental Defense Fund; WestWater Research, 2016).
Colorado mechanisms specifically for instream flows, with some applicability for other uses, are described in a 2020 Colorado Water Trust white paper (Colorado Water Trust).
Shepherding Challenges
A 2017 paper from University of Colorado researchers discussed issues raised under Colorado water law with shepherding appropriated water to Lake Powell to protect water levels and provide compact security (MacDonnell & Castle, 2017).
Homestake Release
Through a voluntary effort conceived by Front range water users, a 1,666.9 acre foot release was made over the course of several days in September of 2020 from the Homestake Reservoir on a tributary to the Eagle River, itself a tributary to the Colorado River. The water released would have otherwise been transported across the Continental Divide for urban water use. In a comprehensive review of the release (Colorado Division of Water Resources, 2021), the Colorado Division of Water Resources found that it was able to legally shepherd the additional water to the state line using existing administrative tools. Tracking the released water in the stream was fairly straightforward in Homestake Creek and the Eagle River, where the release was a large portion of the total stream volume, but was not possible in the Colorado mainstem to the state line because the amount released was dwarfed by the total water volume in the river, interactions with a complex set of upstream and downstream water management actions, and insufficient instrumentation to measure all influences on streamflow. However, given that administrative actions prevented the diversion of additional water downstream from the release, it can reasonably be assumed that the water made it to the Colorado-Utah state line.
Emery County, UT Real Time Monitoring and Control
In Emery County, a Real Time Monitoring and Control System (RTMCS) was installed beginning in 1993 with gauging stations on the San Rafael River and its tributaries as well as canals and springs and has grown into an extensive network with automated control structures and data viewable on a public website. A review of the program (Green, Hansen, Narayanan, & Green, 2020) credits the system with reducing diversions required to serve irrigators, improving conveyance efficiency, and improving transparency and trust among water users.System Conservation Pilot Program Final Report
The Upper Colorado River Commission’s final report (UCRC Staff, Wilson Water Group, 2018) on the SCPP includes a discussion of issues related to pricing.
Grand Valley Water Users Association Conserved Consumptive Use Program
The Grand Valley Water Users Association (GVWUA) in Western Colorado administered an SCPP program for its members through a lottery system. Elements that went into the cost proposed for the program included ensuring that the GVWUA was compensated adequately for the administrative work required to run the program, as well as that the system as a whole would benefit from participating in the program through revenue generated for infrastructure upgrades (J-U-B Engineers and Grand Valley Water Users Association, 2019).
Tomichi Creek Water Conservation Project
A project on Tomichi Creek in the Upper Gunnison Basin paid irrigators to stop irrigating early in 2018 and measured the impacts on streamflows. The final report on the project (Kruthaupt, 2019) notes that 2018 was a very dry year, which reduced the value of the fallowing payments to participants, because hay and pasture prices go up in dry conditions. The dryness of the year also reduced the total amount of water conserved, since less was available, but it increased the importance of that water for the health of the stream.
Tomichi Creek Water Conservation Project
On Tomichi Creek in Colorado’s Upper Gunnison Basin, Trout Unlimited paid several irrigators to reduce their diversions during the drought year of 2018, with extensive monitoring of streamflows as well as consumptive use. Comparing streamflows and fish mortality in 2018 with similar drought years in 2002 and 2012 indicated significantly improved streamflow and trout fishery conditions as a result of the irrigation curtailments (Kruthaupt, 2019).
Water Bank Work Group Secondary Impact Study
The Colorado Water Bank Work Group contracted with BBC Research and Consulting to conduct economic analysis and stakeholder focus groups to assess the potential secondary impacts of demand management on communities in Western Colorado river basins (BBC Research & Consulting; ERO Resources; Headwaters Corporation, 2020).
University of Wyoming Economic Assessment
The University of Wyoming study was designed by the University, in partnership with The Nature Conservancy, the Wyoming Stock Growers’ Association and University of Wyoming Extension (Hansen, Coupal, Yeatman, & Bennett, 2021). It drew on both agricultural producer surveys and economic modeling.
Upper Gunnison Study
The Upper Gunnison River Water Conservancy District commissioned Harvey Economics to study the potential economic impacts of irrigation water curtailment in the Upper Gunnison Basin under various scenarios (Harvey Economics, 2020).