The Middle San Joaquin-Lower Watershed covers an area of approximately 6,375 square miles and is located in central California. The hydrology of the watershed is primarily driven by precipitation, with the majority of annual precipitation occurring in the winter months. The snowpack in the Sierra Nevada Mountains, which is a source of water for the watershed, has been declining in recent years due to climate change. Surface water in the watershed is primarily sourced from the San Joaquin River and its tributaries, including the Merced River and the Tuolumne River. The river is heavily regulated, with several large reservoirs along its course that store water for agricultural and urban use. Reservoir constituents include sediment, nutrients, and pollutants from agricultural runoff, which can lead to water quality issues. Interesting climatic facts include the region's susceptibility to drought and extreme heat events, which can impact agriculture and water resources. Climate change is predicted to exacerbate these challenges in the coming years.