Can Snow Water Equivalent Products Improve Forecasts at the Colorado Basin River Forecast Center?

Abstract:

The amount of water stored as mountain snow has a large impact on streamflow volumes in the upper Colorado River and Eastern Great Basins. The Colorado Basin River Forecast Center (CBRFC) creates water supply forecasts starting in January for spring runoff volumes. Streamflow forecasts and water supply information developed by the CBRFC are used to provide impact-based decision support services for a broad range of stakeholders throughout the region. As active members of the Colorado River Climate and Hydrology Workgroup, the CBRFC continually tries to improve their forecasts by incorporating new information. There are several gridded snow water equivalent products that cover the Colorado River Basin, including SWANN, NOHRSC, and CU-JPL Real-Time Snowpack Estimations from Satellites. In addition, there are several Airborne Snow Observatory overflights in the 2018 and 2019 water years. An evaluation of these products is performed in the context of the CBRFC’s current forecasting system. The current hydrologic modeling system consists of SNOW-17, the Sacramento Soil Moisture Accounting Model (SACSMA) and unit hydrograph routing. These are calibrated lumped-parameter models with hydrologic response units based on elevation.