The Lower Gila Painted Rock Reservoir Watershed is located in southwestern Arizona, covering an area of approximately 2,990 square miles. The hydrology of the watershed is characterized by a dry desert climate, with annual precipitation averaging around 6 inches. Snowpack is generally not significant in this region. Surface water sources in the area include the Lower Gila River, which flows through the Painted Rock Reservoir, and several smaller streams and washes. The reservoir is used for irrigation and flood control purposes, and its constituents include sediment, nutrients, and organic matter. Interesting climatic facts and trends include rising temperatures and a decrease in annual precipitation in recent years. Climate change poses a significant threat to water resources in the region, and efforts are being made to improve water management and conservation practices.