Estimated crop irrigation water use withdrawals in Willcox Groundwater Basin, Arizona for 2023

Observations of irrigated agricultural land within the Willcox Groundwater Basin in Arizona. Crops were verified in situ three times in 2023, first on May 3rd, then on Aug 16th, and finally on Dec 19th; 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 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.

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

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

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.