Aerial Snow Surveys of the San Joaquin River Basin

In Fall 2016, Friant Water Authority launched a groundbreaking aerial snow survey project in the San Joaquin River basin that will deepen our understanding of annual water supply availability for the Friant Division. It will also provide useful information to other agencies with flood management, hydropower, or water supply responsibilities.

The project is being conducted in partnership with the National Aeronautics and Space Administration (NASA) out of its Jet Propulsion Laboratory, which also operates the Aerial Snow Observatory (ASO) in the Merced, Tuolumne, and Kings river basins, and in the Eastern Sierra drainages to Mono Lake and the Owens Valley.

ASO relies on aircraft-based LIDAR (light detection and ranging) technology to measure the depth of snow on the ground. When those measurements are compared to baseline measurements of ground elevation, the results indicate the snow depth. Researchers and water managers can then use that information to estimate how much water will be available and better predict inflow into reservoirs. During Winter 2016 through Spring 2017 aerial surveys were conducted monthly. At the peak of the wet season, the surveys measured approximately 2.7 million acre-feet in the upper San Joaquin watershed.