The Cottonwood Tijuana watershed (HUC 18070305) spans across approximately 244 square miles along the US-Mexico border. The hydrology of the watershed is influenced by its location in a semi-arid region, with precipitation mainly occurring during the winter months. The area is also characterized by seasonal snowpack, which can contribute to surface water runoff during spring and summer. The Cottonwood Creek Reservoir serves as the primary water source for the region, with constituents including sediment, nutrients, and bacteria. In recent years, the watershed has experienced drought conditions, leading to decreased water availability and challenges for agriculture and wildlife. Additionally, the region is susceptible to wildfires and flash floods. Climate projections indicate that the area may experience more frequent and intense droughts and heatwaves in the future.