Estimated crop irrigation water use withdrawals in Butler Valley Groundwater Basin, Arizona for 2020

Observations of irrigated agricultural land within the Butler Valley Groundwater Basin in Arizona. Crops were verified in situ twice in 2020 first on March 11th and again on August 11th; based on digitized field boundaries. Field boundaries were digitized from U.S. Department of Agriculture, National Agricultural Imagery Program images dated 2019 and supplemented with Landsat and Sentinel2 imagery collections accessed via the U.S. Geological Survey LandLook Viewer (https://landlook.usgs.gov/) and Sentinel Hub, Sentinel Playground (https://apps.sentinel-hub.com/sentinel-playground). 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.