Water Resources Research Act Program

Details for Project ID 2007CO153B

Effects of Pine Beetle Infestations on Water Yield and Water Quality at the Watershed Scale in Northern Colorado

Institute: Colorado
Year Established: 2007 Start Date: 2007-03-01 End Date: 2008-02-29
Total Federal Funds: $15,000 Total Non-Federal Funds: $7,778

Principal Investigators: Reagan Waskom, John Stednick

Project Summary: A beetle epidemic in Colorado is killing trees in the subalpine and montane settings. The decrease in forest canopy due to defoliation will result in decreased precipitation interception and decreased summer evapotranspiration. Changes in these hydrologic process rates will result in increased soil moisture and increased annual water yield (streamflow). A series of watersheds that have been aerially mapped for beetle kill by the USDA Forest Service in Northern Colorado will be selected. A progression of watershed areas that have been beetle killed will be used to assess if water yield increases are measurable using nearby relatively undisturbed watershed as a paired watershed study (control vs. treatment watershed comparisons using analysis of covariance). Streamflow records from gauging stations operated by the US Geological Survey will be used. Streamflow metrics including annual water yield, peak flows, and low flows will beinvestigated using analysis of covariance and flow duration curve analysis. The literature suggests that the disruption of nutrient cycles will result in increased nitrate nitrogen concentrations in surface waters. Water quality samples will be collected from the selected watersheds and analyzed. The progression of watershed areas affected by beetle kill should enable us to determine a threshold of response, both for water quantity and water quality. The ability to more accurately predict water yield from watersheds with beetle killed areas is significant for downstream users and water mangers.