<p>The Western United States has been in drought for 23 years, and water levels across the region have dropped to historic lows. In August 2021, the United States Bureau of Reclamation declared the first-ever shortage on the Colorado River, cutting water deliveries for many users. Lake Mead and Lake Powell continued to fall through 2022, and the cuts grew. Industrial farming in arid and semi-arid regions depends on imported water for irrigation, and fallowing cropland can lead to significant water savings in a short period. Farmers can reduce water usage quickly by keeping cultivated land out of production during a typical growing season. Here, we propose an optimization model to find the best fallowing plan based on estimated crop water consumption, commodity prices, and other land, water, and budget constraints. The model is generalizable to any region facing water scarcity that is looking to set up agricultural fallowing programs. To show how the model works, we used publicly available crop and weather data to estimate crop water usage across water agencies in a case study region and to estimate optimum fallowing plans for two major water supply systems. The optimized plans help interested organizations decide which groups of crops to fallow and what payment per acre farmers may receive to meet specific water conservation goals. We compare these results with the fallow rates currently proposed to farmers.</p>