Food Supplies and Demand Reliant on Large Irrigation Dams

Water is an integral part of agricultural practices, with agriculture being the largest user of surface water in the United States. Agriculture's reliance on surface water is strengthening as climate change and growing populations are stressing irrigated croplands. This surface water is primarily stored by a complex network of dams, but despite our reliance on surface water for irrigation, we lack a spatially detailed record of irrigation dam command areas. Therefore, we assigned irrigation command areas to the approximately 1,100 large irrigation dams in the continental United States by combining a tiered assignment strategy with field level infrastructure and agricultural data. We showed that these large irrigation dam command areas are responsible for 10.7 million acres of cropland. This translates to approximately 13.3 billion dollars of crops annually that depend on these large irrigation dams for water. The high-resolution, crop specific assignment of these command areas allows for water scarcity assessments that can be used for better water management decisions to address the changing environmental conditions and public demand pressuring the nation's agriculture and water infrastructure.