Lower San Juan

Watershed Hydrology

The Lower San Juan Watershed (HUC 14080205) covers approximately 3,851 square miles in the southwestern United States. The area is characterized by an arid climate, with precipitation averaging around 8 inches annually. The region is also susceptible to flash floods due to its steep topography and lack of vegetation. The hydrology of the watershed is influenced by the San Juan River, which is the largest tributary of the Colorado River. Snowpack in the watershed is typically low, with less than 10 inches of snowfall per year. Surface water in the area is primarily supplied by the San Juan River and its tributaries. The watershed is home to several reservoirs, including the Navajo Reservoir, which is the second-largest reservoir in the state of New Mexico. The reservoir serves as a source of water for the Navajo Nation and provides opportunities for outdoor recreation. In recent years, the area has experienced a trend towards warmer temperatures and longer dry spells. This has led to increased concerns over drought and water scarcity in the region.


Surface Flows

Lower San Juan Watershed

Snowpack Depths

Lower San Juan Watershed

Dams & Reservoirs

Lower San Juan Watershed

Groundwater Levels

Lower San Juan Watershed

Lower San Juan Rivers

Rivers of the Watershed