Agricultural water use: Difference between revisions
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[[File:CRB_ag_areas_map_2015_Moving_Forward.png|thumb|550px|Figure 1. Irrigated agricultural lands within the U.S. potentially receiving Colorado River water, both inside and outside of the physical basin, are shown in yellow. Some of these irrigated lands may receive non-tributary groundwater, or water from tributaries not administratively treated as Colorado River water, such as from the Gila River. Irrigated lands in Mexico, totaling about 0.5 million acres, are not shown. Irrigated acreage is mapped from the 2011 National Land Cover Database. (Source: [https://www.usbr.gov/lc/region/programs/crbstudy/MovingForward/Phase1Report.html Moving Forward Phase 1 Report], 2015.)]] | [[File:CRB_ag_areas_map_2015_Moving_Forward.png|thumb|550px|Figure 1. Irrigated agricultural lands within the U.S. potentially receiving Colorado River water, both inside and outside of the physical basin, are shown in yellow. Some of these irrigated lands may receive non-tributary groundwater, or water from tributaries not administratively treated as Colorado River water, such as from the Gila River. Irrigated lands in Mexico, totaling about 0.5 million acres, are not shown. Irrigated acreage is mapped from the 2011 National Land Cover Database. (Source: [https://www.usbr.gov/lc/region/programs/crbstudy/MovingForward/Phase1Report.html Moving Forward Phase 1 Report], 2015.)]] | ||
Agricultural water use accounts for about 75% of the beneficial uses of the Colorado River and about 60% of all [[consumptive uses and losses]], as estimated over the 2000-2019 period<ref name="cul"/><ref name="richter" /> | Agricultural water use accounts for about 75% of the beneficial uses of the Colorado River and about 60% of all [[consumptive uses and losses]], as estimated over the 2000-2019 period.<ref name="cul"/><ref name="richter" /> Water from the Colorado River irrigates approximately 3.2 million acres within the physical basin, including the Salton Sea watershed and Mexico. Water exported from the Colorado River Basin provides supplemental (partial) irrigation for up to 2 million acres outside of the basin (Figure 1).<ref name="cohen" /> While a diverse range of agricultural products are grown with Colorado River water, livestock feed crops (alfalfa, hay, silage, pasture) account for the majority (~60%) of the basin's agricultural water use.<ref name="richter" /> | ||
In the Upper Basin states (Colorado, Utah, Wyoming, New Mexico), 2.5 to 3.0 million acre-feet (maf) of Colorado River water are consumptively used annually on about 1.4 million acres of crops and pasture within the | In the Upper Basin states (Colorado, Utah, Wyoming, New Mexico), 2.5 to 3.0 million acre-feet (maf) of Colorado River mainstem and tributary water are consumptively used annually on about 1.4 million acres of crops and pasture within the basin, as of 2020-2024. <ref name="uc1" /> Another 0.3 maf of exported Colorado River water is used for agriculture within the Upper Basin states, in the South Platte, Arkansas, and Rio Grande basins, and along the Wasatch Front (Figure 1).<ref name="richter" /> | ||
In the Lower Basin states (California, Arizona, Nevada), 4.0 to 4.5 | In the Lower Basin states (California, Arizona, Nevada), 4.0 to 4.5 maf of Colorado River mainstem water are consumptively used annually on about 1.4 million acres of crops and pasture within the basin, including the Salton Sea watershed.<ref name="richter" /><ref name="wobus" /> Less than 0.1 maf of exported Colorado River water is used for agriculture within the Lower Basin states, entirely in southern California (Figure 1).<ref name="cohen" /> | ||
In Mexico, 1.2 to 1.3 maf of Colorado River water are consumptively used annually on about 0.5 million acres of crops and pasture within the basin.<ref name="cohen" /><ref name="richter" /> The only water exported out of the basin within Mexico is for municipal and industrial use. | |||
Most of the irrigated acreage that uses Colorado River water is overseen by irrigation districts. Irrigation districts act as diversion and ditch managers and oversee ditch maintenance; farmers pay dues to irrigation districts for water deliveries. | Most of the irrigated acreage that uses Colorado River water is overseen by irrigation districts. Irrigation districts act as diversion and ditch managers and oversee ditch maintenance; farmers pay dues to irrigation districts for water deliveries. | ||
Managing agricultural water use is complicated by the difficulty of accurately quantifying the actual consumptive use by crops, from the field scale to basin scale. In the past decade, new methodologies that combine satellite imagery with in-situ measurements and physical modeling have come to the forefront (see [[Evapotranspiration (ET)]]). In September 2022, Reclamation and the Upper Colorado River Commission (UCRC) adopted a satellite-based method, eeMETRIC, as the standard for measuring evapotranspiration (ET) and agricultural consumptive water use in the Upper Basin. | Managing agricultural water use is complicated by the difficulty of accurately quantifying the actual consumptive use by crops, from the field scale to basin scale. In the past decade, new methodologies that combine satellite imagery with in-situ measurements and physical modeling have come to the forefront (see [[Evapotranspiration (ET)]]). In September 2022, Reclamation and the Upper Colorado River Commission (UCRC) adopted a satellite-based method, eeMETRIC, as the standard for measuring evapotranspiration (ET) and agricultural consumptive water use in the Upper Basin.<ref name="oconnor" /> | ||
As basin stakeholders discuss the need for further reductions in basinwide water use in the face of critically low reservoir levels, increased attention has fallen on the water use in the agricultural sector. Short-term reductions in water use are being pursued through payouts to Lower Basin agricultural producers to fallow fields | As basin stakeholders discuss the need for further reductions in basinwide water use in the face of critically low reservoir levels, increased attention has fallen on the water use in the agricultural sector. Short-term reductions in water use are being pursued through payouts to Lower Basin agricultural producers to fallow fields and/or reduce irrigation intensity;<ref name="lc1" /> longer-term strategies for water conservation include measures such as shifting planted acreage to lower-water-use crops; installing more efficient irrigation technology; and reducing conveyance losses (e.g., better monitoring of diversions, lining ditches).<ref name=udall /> The challenge will be to invest limited funds in ways that both reduce overall water use and maintain economic viability of the agricultural sector. | ||
==Data and tools== | ==Data and tools== | ||
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The Reclamation Consumptive Uses and Losses Reports (since 2006, covering only the Upper Basin) contain estimates of aggregate agricultural use within the Upper Basin, based on mapped irrigated acreage and the calculated consumption by crop and location. These estimates may change significantly in the future due to the new method adopted in 2022 by the UCRC and Reclamation. | The Reclamation Consumptive Uses and Losses Reports (since 2006, covering only the Upper Basin) contain estimates of aggregate agricultural use within the Upper Basin, based on mapped irrigated acreage and the calculated consumption by crop and location. These estimates may change significantly in the future due to the new method adopted in 2022 by the UCRC and Reclamation. | ||
The Reclamation Water Accounting Reports (covering only the Lower Basin) breaks down consumptive use by point of diversion, which | The Reclamation Water Accounting Reports (covering only the Lower Basin) breaks down consumptive use by point of diversion, which separately reports the water usage of many, but not all, irrigation districts and other major agricultural users. But these Reports only aggregate water use by state, not by type of use (e.g., agriculture/municipal/industrial). | ||
* See [[Consumptive uses and losses]] for more details and links to these reports. | * See [[Consumptive uses and losses]] for more details and links to these reports. | ||
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<ref name="uc1"> Reclamation. (2025). Upper Colorado River System, Consumptive Uses and Losses 1971-2024: State, Major Tributary Data Summaries and Figures v24.5 - updated: 12/01/2025. https://www.usbr.gov/uc/DocLibrary/Reports/ConsumptiveUsesLosses/20251201-UpperColoradoCUL1971-2025_v24.5_MajorTribSummary-DataSummariesFigures.xlsx | |||
</ref> | |||
<ref name="wobus">Wobus, C., Nash, C., Culp, P. W., Kelly, M., and Kennedy, K. (2024). Simplified agricultural water use accounting in the Colorado River basin using OpenET. Environmental Research Letters. https://doi.org/10.1088/1748-9326/ad984b | |||
</ref> | |||
<ref name="oconnor">O'Connor, R. 2022. "Upper Colorado River Commission and Bureau of Reclamation move to satellite-based ET for consistent consumptive water use measurements." Blog post, OpenET. https://etdata.org/upper-colorado-river-commission-bureau-of-reclamation-satellite-based-et-consistent-consumptive-water-use-measurements/ | |||
</ref> | |||
<ref name="lc1">Reclamation. (2025.) "Lower Colorado River Basin System Conservation and Efficiency Program." Web page: https://www.usbr.gov/lc/LCBConservation.html | |||
</ref> | |||
<ref name=udall>Udall, B. and G. Peterson. (2017). Agricultural Water Conservation in the Colorado River Basin: Alternatives to Permanent Fallowing. Research Synthesis and Outreach Workshop, Part 1 (Executive Summary). Colorado Water Institute, Colorado State University. Completion Report No. 232, December 2017. https://www.crbagwater.colostate.edu/files/CWI_Completion_Report232_Part1.pdf | |||
</ref> | |||
</references> | </references> | ||
Latest revision as of 18:48, 25 February 2026
Overview
Agricultural water use accounts for about 75% of the beneficial uses of the Colorado River and about 60% of all consumptive uses and losses, as estimated over the 2000-2019 period.[1][2] Water from the Colorado River irrigates approximately 3.2 million acres within the physical basin, including the Salton Sea watershed and Mexico. Water exported from the Colorado River Basin provides supplemental (partial) irrigation for up to 2 million acres outside of the basin (Figure 1).[3] While a diverse range of agricultural products are grown with Colorado River water, livestock feed crops (alfalfa, hay, silage, pasture) account for the majority (~60%) of the basin's agricultural water use.[2]
In the Upper Basin states (Colorado, Utah, Wyoming, New Mexico), 2.5 to 3.0 million acre-feet (maf) of Colorado River mainstem and tributary water are consumptively used annually on about 1.4 million acres of crops and pasture within the basin, as of 2020-2024. [4] Another 0.3 maf of exported Colorado River water is used for agriculture within the Upper Basin states, in the South Platte, Arkansas, and Rio Grande basins, and along the Wasatch Front (Figure 1).[2]
In the Lower Basin states (California, Arizona, Nevada), 4.0 to 4.5 maf of Colorado River mainstem water are consumptively used annually on about 1.4 million acres of crops and pasture within the basin, including the Salton Sea watershed.[2][5] Less than 0.1 maf of exported Colorado River water is used for agriculture within the Lower Basin states, entirely in southern California (Figure 1).[3]
In Mexico, 1.2 to 1.3 maf of Colorado River water are consumptively used annually on about 0.5 million acres of crops and pasture within the basin.[3][2] The only water exported out of the basin within Mexico is for municipal and industrial use.
Most of the irrigated acreage that uses Colorado River water is overseen by irrigation districts. Irrigation districts act as diversion and ditch managers and oversee ditch maintenance; farmers pay dues to irrigation districts for water deliveries.
Managing agricultural water use is complicated by the difficulty of accurately quantifying the actual consumptive use by crops, from the field scale to basin scale. In the past decade, new methodologies that combine satellite imagery with in-situ measurements and physical modeling have come to the forefront (see Evapotranspiration (ET)). In September 2022, Reclamation and the Upper Colorado River Commission (UCRC) adopted a satellite-based method, eeMETRIC, as the standard for measuring evapotranspiration (ET) and agricultural consumptive water use in the Upper Basin.[6]
As basin stakeholders discuss the need for further reductions in basinwide water use in the face of critically low reservoir levels, increased attention has fallen on the water use in the agricultural sector. Short-term reductions in water use are being pursued through payouts to Lower Basin agricultural producers to fallow fields and/or reduce irrigation intensity;[7] longer-term strategies for water conservation include measures such as shifting planted acreage to lower-water-use crops; installing more efficient irrigation technology; and reducing conveyance losses (e.g., better monitoring of diversions, lining ditches).[8] The challenge will be to invest limited funds in ways that both reduce overall water use and maintain economic viability of the agricultural sector.
Data and tools
Reclamation reporting of consumptive uses and losses
The Reclamation Consumptive Uses and Losses Reports (since 2006, covering only the Upper Basin) contain estimates of aggregate agricultural use within the Upper Basin, based on mapped irrigated acreage and the calculated consumption by crop and location. These estimates may change significantly in the future due to the new method adopted in 2022 by the UCRC and Reclamation. The Reclamation Water Accounting Reports (covering only the Lower Basin) breaks down consumptive use by point of diversion, which separately reports the water usage of many, but not all, irrigation districts and other major agricultural users. But these Reports only aggregate water use by state, not by type of use (e.g., agriculture/municipal/industrial).
- See Consumptive uses and losses for more details and links to these reports.
Additional resources
Water to Supply the Land: Irrigated Agriculture in the Colorado River Basin
The intent of this 2013 report by the Pacific Institute is to improve understanding of crop acreages and water use in the basin. It also describes a set of scenarios in which some irrigation water could be conserved and used for other purposes without reducing the amount of land in production. Note that the report only covers agricultural uses occurring within the basin's boundaries, not those outside the basin that also use Colorado River water.
Lists and directories of major irrigation districts
Major irrigation districts and water users are tabulated by Reclamation for both the Upper and Lower basins:
Notes
- ↑ See the breakdown of agricultural water use and other uses and losses, and data sources, on the Consumptive uses and losses page. Note that the Richter et al. (2024) study agrees that agricultural water use represents about 75% of direct human uses ("beneficial use"), but they calculate that agricultural water use represents 52% of all consumptive uses and losses, not 60%. This is because they use a much higher number for riparian evapotraspiration (i.e., transit) losses than is accepted by Reclamation and other sources, which makes their overall consumptive uses and losses "pie" larger.
- ↑ 2.0 2.1 2.2 2.3 2.4 Richter, B. D., Lamsal, G., Marston, L., et al. (2024). New water accounting reveals why the Colorado River no longer reaches the sea. Communications Earth & Environment, 5(1), 134. https://doi.org/10.1038/s43247-024-01291-0
- ↑ 3.0 3.1 3.2 Cohen, M., Christian-Smith, J., and Berggren, J. (2013). Water to supply the land: Irrigated agriculture in the Colorado River Basin. Pacific Institute. 110 pp. https://pacinst.org/wp-content/uploads/2013/05/pacinst-crb-ag-1.pdf
- ↑ Reclamation. (2025). Upper Colorado River System, Consumptive Uses and Losses 1971-2024: State, Major Tributary Data Summaries and Figures v24.5 - updated: 12/01/2025. https://www.usbr.gov/uc/DocLibrary/Reports/ConsumptiveUsesLosses/20251201-UpperColoradoCUL1971-2025_v24.5_MajorTribSummary-DataSummariesFigures.xlsx
- ↑ Wobus, C., Nash, C., Culp, P. W., Kelly, M., and Kennedy, K. (2024). Simplified agricultural water use accounting in the Colorado River basin using OpenET. Environmental Research Letters. https://doi.org/10.1088/1748-9326/ad984b
- ↑ O'Connor, R. 2022. "Upper Colorado River Commission and Bureau of Reclamation move to satellite-based ET for consistent consumptive water use measurements." Blog post, OpenET. https://etdata.org/upper-colorado-river-commission-bureau-of-reclamation-satellite-based-et-consistent-consumptive-water-use-measurements/
- ↑ Reclamation. (2025.) "Lower Colorado River Basin System Conservation and Efficiency Program." Web page: https://www.usbr.gov/lc/LCBConservation.html
- ↑ Udall, B. and G. Peterson. (2017). Agricultural Water Conservation in the Colorado River Basin: Alternatives to Permanent Fallowing. Research Synthesis and Outreach Workshop, Part 1 (Executive Summary). Colorado Water Institute, Colorado State University. Completion Report No. 232, December 2017. https://www.crbagwater.colostate.edu/files/CWI_Completion_Report232_Part1.pdf