The Los Angeles Watershed (HUC 18070105) covers a land area of approximately 1,387 square miles and is home to over 5 million people. The hydrology of the watershed is heavily influenced by the Sierra Nevada Mountains, which provide a significant amount of runoff and snowpack each year. The snowpack in the Sierra Nevada range is critical to the surface water supply for the Los Angeles area, as it feeds into the Los Angeles Aqueduct. The surface water in the watershed is primarily stored in reservoirs such as Lake Oroville and Lake Perris, which provide drinking water and hydroelectric power to the area. Interesting climatic facts and trends in the area include an increasing frequency and intensity of wildfires due to drought conditions and a changing climate. Additionally, the Los Angeles area has experienced a significant decline in annual rainfall over the past century, leading to increased reliance on imported water sources.