Airborne Snow Observatory: Hetch Hetchy Basin Snow Water Equivalent Time Series, 2013

The Airborne Snow Observatory (ASO) 2013 demonstration mission collected detailed basin-wide snow information for portions of the Tuolumne Basin in California and the Uncompahgre Basin in Colorado. The ASO uses an imaging spectrometer and LiDAR systemmounted in an aircraft for collecting snow depth and snow albedo. Snow depth is combined with a calculated density field to produce distributed snow water equivalent. Weekly flights over the Tuolumne produced both basin-wide and sub-basin SWE estimates that were used in the USGS Precipitation Runoff Model to provide runoff forecasts for Hetch Hetchy Reservoir, the source of 85% of the water supply for 2.5 million people on the San Francisco Peninsula. Information produced by the ASO data collection and PRMS modeling is designed to improve the ability of reservoir operators to more efficiently allocate the last half of the recession limb of snowmelt inflow and be more assured of meeting operational mandates.