The Big Navarro Garcia Watershed (HUC 18010108) covers an area of approximately 311 square miles in northwestern Mexico. The watershed is characterized by a Mediterranean climate, with mild, wet winters and hot, dry summers. Snowpack is not a significant source of water for the watershed. Surface water is primarily supplied by the Navarro and Garcia Rivers, which flow into the Pacific Ocean. The watershed also contains several reservoirs, including the El Cajon and Cerro Prieto Reservoirs, which are used for irrigation, hydroelectric power generation, and domestic water supply. The reservoirs contain a variety of constituents, including sediment, organic matter, and nutrients. Climate change is expected to have significant impacts on the watershed, including increased temperatures, decreased precipitation, and increased frequency of extreme weather events.