Estimated crop irrigation water use withdrawals in Lower Gila Groundwater Basin (excluding Wellton-Mohawk Irrigation and Drainage District), Arizona for 2024

Observations of irrigated agricultural land (excluding Wellton-Mohawk Irrigation and Drainage District) in the Lower Gila Groundwater Basin in Arizona. Lower Gila Groundwater Basin consists of three subbasins; Childs Valley in Pima County, Dendora Valley in Maricopa County, and Wellton-Mohawk in Yuma County. No irrigated agricultural land is found in the Childs Valley Subbasin or Pima County. Crops were verified in situ three times in 2024, first on May 9th, then on Jun 7th, and finally on Aug 28th; based on digitized field boundaries. Field boundaries were digitized from U.S. Department of Agriculture, National Agriculture Imagery Program County Mosaic 2023 imagery for Arizona and supplemented with the Sentinel2 imagery collection accessed via the European Space Agency, Copernicus Browser (https://browser.dataspace.copernicus.eu/). Satellite images were also used in conjunction with OpenET Farm and Ranch Management Support (FARMS; https://farms.etdata.org/) to identify the length of the growing season and crop condition. Water withdrawals were calculated using the modified Blaney-Criddle model of calculating consumptive use (U.S. Bureau of Reclamation, 1992 appendix A) using crop coefficients from Doorenbos and Pruitt (1975), the number of acres with active crops, crop condition, and irrigation system efficiency. The withdrawal equation was modified from "Water withdrawals for irrigation, municipal, mining, thermoelectric-power, and drainage uses in Arizona outside of active management areas, 1991-2000" (Tadayon, 2005) to account for variations in water application. Lower Gila Groundwater Basin consists of three subbasins; Childs Valley in Pima County, Dendora Valley in Maricopa County, and Wellton-Mohawk in Yuma County. No irrigated agricultural land is found in the Childs Valley Subbasin or Pima County.

Data are available as a shapefile for visualization or as a stand-alone csv table for attributes only.

Doorenbos, J. and Pruitt, W.O.,1975, Guidelines for predicting crop water requirements: Irrigation and drainage paper FAO No. 24, p195, https://www.nrc.gov/docs/ML1821/ML18215A282.pdf.

Tadayon, Saeid, 2005, Water withdrawals for irrigation, municipal, mining, thermoelectric-power, and drainage uses in Arizona outside of Active Management Areas, 1991–2000: U.S. Geological Survey Scientific Investigations Report 2004-5293, 28 p, https://doi.org/10.3133/sir20045293.

U.S. Bureau of Reclamation, 1992, Plan of study and methods manual for Colorado River system consumptive uses and losses report 1985–1990: U.S. Bureau of Reclamation, Appendix A, 23 p.