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ARS Home » Pacific West Area » Boise, Idaho » Northwest Watershed Research Center » Research » Publications at this Location » Publication #310985

Research Project: Understanding Snow and Hydrologic Processes in Mountainous Terrain with a Changing Climate

Location: Northwest Watershed Research Center

Title: Bedrock infiltration estimates from a catchment water storage-based modeling approach in the rain snow transition zone

Author
item KORMOS, PATRICK - Boise State University
item MCNAMARA, JIM - Boise State University
item Seyfried, Mark
item MARSHALL, HANS-PETER - Boise State University
item Marks, Danny - Danny
item FLORES, A - Boise State University

Submitted to: Journal of Hydrology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/14/2015
Publication Date: 3/24/2015
Citation: Kormos, P., Mcnamara, J., Seyfried, M.S., Marshall, H., Marks, D.G., Flores, A. 2015. Bedrock infiltration estimates from a catchment water storage-based modeling approach in the rain snow transition zone. Journal of Hydrology. 525:231-248.

Interpretive Summary: Estimates of bedrock infiltration from mountain catchments are difficult to make but are essential to water resource managers. The research presented in this paper takes advantage of a fine-scale measurement network over a hillslope catchment located within the rain-snow transition zone above Boise, Idaho. It uses measurements of streamflow, precipitation and detailed snow sampling throughout the year to show that about 34% of precipitation for the 2011 water year became ground water, that aspect is important, and that – in this location -peak bedrock infiltration occurs during rain-on-snow events.

Technical Abstract: Estimates of bedrock infiltration from mountain catchments in the western U.S. are essential to water resource managers because they provide an estimate of mountain block recharge to regional aquifers. On smaller scales, bedrock infiltration is an important term in water mass balance studies, which attempt to estimate hydrologic states and fluxes in watersheds with fractured or transmissive bedrock. We estimate the spatiotemporal distribution of bedrock infiltration in a small catchment in the rain snow transition zone in Idaho, using the difference between measured stream discharge and modeled soil drainage. The accuracy of spatial patterns in soil water storage are optimized, rather than the more common approach of minimizing error in integrated quantities such as streamflow. Bedrock infiltration is estimated to be 311 mm ± 48 mm for the 2011 water year, which is 34% ±12% of the precipitation (95% confidence). Soils on the southwest facing slope drain more often throughout the snow season, but the northeast facing slope contributes more total soil drainage for the water year. Peaks in catchment soil drainage and bedrock infiltration coincide with rain on snow events.