Next Generation USGS Snow Hydrology Monitoring Activities to Improve Water Availability Assessments in the Upper Colorado River Basin

In the Upper Colorado River Basin (UCRB), snowmelt is the primary source of annual streamflow, with the year-to-year variability in snowpack water storage driving variations in runoff volume and timing. The accurate characterization of seasonal snow water resources is vital for water management in the UCRB. A substantial challenge of characterizing the seasonal snowpack is that it exhibits variability both spatially and temporally across the landscape. This variability is a result of meteorological processes and their interactions with topography and land surface features like forests that have been changing rapidly in the basin. Representative spatial and temporal snow, soil moisture, and streamflow observations in previously unmonitored environments can provide valuable data to inform modeling of water-cycle components. Therefore, beginning in 2021, the U.S. Geological Survey (USGS) Next Generation Water Observing System (NGWOS) began collecting these data types that are of high value for supporting snow modeling applications and improved water-supply forecasting in the UCRB. This presentation will describe USGS NGWOS snow hydrology monitoring activities including: (1) continuous snow and soil moisture energy balance station observations in environments where existing monitoring is absent or limited; (2) spatially distributed snow measurements via ground, uncrewed aircraft systems, and airborne-based platforms capturing the complex spatial variability of snow distributions; and (3) streamflow measurements in ungaged basins corresponding with snow data for water-cycle component evaluation. Furthermore, we will describe how these new observations are being used coincident with existing ground and satellite snow monitoring technologies to evaluate and improve snow modeling applications using a physically based snow evolution model (SnowModel).