Estimated crop irrigation water use withdrawals in Harquahala Irrigation Non-Expansion Area Groundwater Basin, Arizona for 2023

Observations of irrigated agricultural land within the Harquahala Irrigation Non-Expansion Area Groundwater Basin in Arizona. Crops were verified in situ three times in 2023, first on May 12th, then on Aug 24th, and finally on Sep 30th; 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.