|GAMBONE, MARILYN - Texas Agrilife Research|
|YEN, HAW - Texas Agrilife Research|
|SANTHI, CHINNASAMY - Texas Agrilife Research|
Submitted to: Journal of the American Water Resources Association
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/22/2015
Publication Date: 12/22/2015
Publication URL: http://handle.nal.usda.gov/10113/61902
Citation: White, M.J., Gambone, M., Yen, H., Arnold, J.G., Harmel, R.D., Santhi, C., Haney, R.L. 2015. Regional blue and green water balances and use by selected crops in the U.S. Journal of the American Water Resources Association. 51(6):1626-1642.
Interpretive Summary: Agriculture is the leading user of water in the U.S. The Soil and Water Assessment Tool (SWAT) coupled with existing data were used to estimate the water required to grow each ton of corn, wheat, sorghum, and soybeans produced in the U.S. and the source of that water. We found severe irrigation related groundwater depletion in the High Plains, and small pockets throughout the Western U.S. This research illustrates the amount of water required to produce the crops we consume and export, and the original source of that water.
Technical Abstract: The availability of fresh water is a prerequisite for municipal development and agricultural production especially in the arid and semi-arid portions of the western U.S. Agriculture is the leading user of water in the U.S. Agricultural water use can be partitioned into green (derived from rainfall) and blue water (irrigation). Blue water can be further subdivided by source. In this research we develop a hydrologic balance by 8-Digit Hydrologic Unit Code (HUC8) using a combination of Soil and Water Assessment Tool (SWAT) simulations and available human water use estimates. These data are used partition agricultural groundwater usage blue water by sustainability and surface water usage by local source or importation. These predictions coupled with reported agricultural yield data are used to predict the virtual water contained in each ton of corn, wheat, sorghum, and soybeans produced and its source. We estimate that these four crops consume 480 km3 of green water annually and 23 km3 of blue water, 12 km3 of which is from groundwater depletion. Regional trends in blue water use from groundwater depletion highlight heavy usage in the High Plains, and small pockets throughout the Western U.S. This information is presented to inform water resources debate by estimating the cost of agricultural production in terms of water regionally. This research illustrates the variable water content of the crops we consume and export, and the source of that water.