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202419 https://hdl.handle.net/2286/R.2.N.202419 http://rightsstatements.org/vocab/InC/1.0/ All Rights Reserved 2025 171 pages Masters Thesis Academic theses en Sharma, Shraddha Vivoni, Enrique R. Kumar, Saurav Li, Jiwei Arizona State University Partial requirement for: M.S., Arizona State University, 2025 Field of study: Civil, Environmental and Sustainable Engineering Climate change intensifies drought severity in the western United States, threatening agricultural water supply reliability. The Colorado River Basin, irrigating over 4.9 million acres, has experienced substantial reservoir declines, with Lake Mead losing 71% of its volume from 2000 to 2022. Following drought declarations and mandatory water cuts in 2022, Arizona agriculture experienced disproportionate impacts, with districts holding junior water rights facing severe reductions while those with senior rights maintaining allocations. This study analyzed the spatial and temporal impacts of Colorado River water shortages on central Arizona agriculture, focusing on two irrigation districts: the Maricopa-Stanfield Irrigation and Drainage District (MSIDD) with junior water rights and the Ak-Chin Indian Community with senior tribal water rights. Using high-resolution satellite imagery from Planet Labs, a Random Forest classification, and water use analysis, this study quantified changes in crop coverage, composition, and water sourcing in the two districts. Results revealed pronounced disparities in their respective responses. Ak-Chin maintained 99% of its fields under active cultivation, preserving crop diversity, and rotation flexibility. MSIDD, on the other hand, experienced a 30% reduction in active farmland, with systematic reductions in water-intensive crops; alfalfa declined 48%, corn fell 70%, while drought-tolerant barley increased 159%. Water use analysis revealed that while Ak-Chin only used Colorado River water supply, MSIDD increased its dependence on other sources by 256% from 32 hm3 (26,000 acre-feet) in 2020 to 114 hm3 (92,000 acre-feet) in 2024, with groundwater level analysis confirming an increased extraction as water table trends reversed from rising (+0.62 m/year) to declining (-1.13 m/year). These findings document how differential water rights determine agricultural vulnerability, with senior rights holders maintaining operational stability, while junior rights holders facing land fallowing and groundwater depletion. This research also shows the effectiveness of remote sensing and machine learning approaches for monitoring agricultural responses to water policy changes, offering a framework for assessing drought impacts. Hydrologic sciences Colorado River Basin Crop Classification CubeSat Drought evapotranspiration Remote Sensing Differential Effects of the Colorado River Drought Declaration on Agricultural Patterns and Water Use in Central Arizona