At higher elevations in the western U.S., seasonal snow accumulation provides the primary source of water input to the terrestrial ecosystem and 60 million people. Recent changes in climate and vegetation cover (e.g. fire suppression, bark beetle infestation, fire) have potentially large, yet unrealized implications for water availability and ecosystem health.

CWEST Participants: Jeff Deems, Noah Molotch, Ben Livneh, K. Barsugli, Keith Jennings, Stacey Bender of the CBRFC and K. Wolter

WWA Snow, Climate and Water Resource Management

Bark Beetle

Bark Beetle impact on trees. Photo credit: Emily Baker

This project investigates the effect of these perturbations on streamflow generation, providing water resource managers guidance as to how operational water supply forecast models may need to be augmented to account for changes in runoff production. PIs are driving the Distribution Hydrology and Vegetation Model (DHSVM) with observed meteorology, distributed satellite-based snowpack information, time-varying maps of leaf area index and forest properties to emulate bark beetle impacts, and parameterization of snow albedo based on observations of dust forcing. Results from beetle-killed canopy alteration suggest slightly greater snow accumulation as a result of less interception and reduced canopy sublimation, contributing to overall increases in annual water yield on the order of 10%. The primary hydrologic impact of dust-on-snow forcing is an increased rate of snowmelt associated with more extreme dust deposition, producing earlier peak streamflow rates for snowmelt-dominated catchments on the order of 1-3 weeks.


Colorado River Basin Map

Colorado River Basin Map

The Snowmelt Perturbations and Water Supply Forecast Errors project is a collaborative effort among Western Water Assessment (WWA) hydrologists, ecologists, weather and climate experts and operational forecasts at the NOAA Colorado Basin River Forecast Center (CBRFC) in an effort to use a suite of modeling and observation techniques to better understand drivers of snow accumulation and melt in the Upper Colorado River Basin with the ultimate goal of improving CBRFC forecasts.

For more information please visit the WWA website and the NOAA CBRFC website.