HR: 0800h
AN: H21A-0193    [Abstracts]
TI: Assessment of Uncertainty of Forest Road Hydrology Modeling with the Distributed Hydrology Soil Vegetation Model (DHSVM)
AU: * Surfleet, C G
EM: chris.surfleet@oregonstate.edu
AF: Oregon State University, Dept. of Forest Engineering Peavy Hall 204, Oregon State University, Corvallis, OR 97331, United States
AU: Skaugset, A E
EM: arne.skaugset@oregonstate.edu
AF: Oregon State University, Dept. of Forest Engineering Peavy Hall 204, Oregon State University, Corvallis, OR 97331, United States
AU: McDonnell, J
EM: jeff.mcdonnell@oregonstate.edu
AF: Oregon State University, Dept. of Forest Engineering Peavy Hall 204, Oregon State University, Corvallis, OR 97331, United States
AB: The effects of forest roads on catchment hydrology and sediment production continue to be the focus of concern for impacts to aquatic habitat. However, these processes are complex and difficult to measure at catchment scales. Consequently, the effects of forest roads on watershed hydrology are often studied using distributed hydrologic models. We examined a popular distributed hydrology model used in the Western USA, the Distributive Hydrology Soil Vegetation Model (DHSVM), to predict changes in peak flows, storm run-off volume, and interception of sub-surface flow from forest roads. We apply DHSVM to a 630 hectare watershed in the headwaters of Oak Creek in the McDonald/Dunn Research Forest, managed by the College of Forestry, Oregon State University. The Generalized Likelihood Uncertainty Estimation (GLUE) approach was used to determine the uncertainty of model output for 10,000 model structures. Estimates of road ditchflow and streamflow from the GLUE assessment of DHSVM were compared to observed road ditchflow and streamflow for 2003-2006. Generally DHSVM simulations provided a reasonable fit to the time series for Oak Creek streamflow. The fit of the time series data diminished with spatial scale and for road ditchflow locations. From the GLUE assessment the percentage of DHSVM model structures that exceeded a Nash/Sutcliffe Efficiency of 0.5 were 44% for Oak Creek streamflow but reduced to a range of 0-9% for road locations. The conceptual model for road interception used within DHSVM did not accurately predict road ditchflow throughout the catchment. Given the many uncertainties observed from DHSVM road ditchflow results we question whether cumulative effects analysis of road influences on peak flows and storm volumes with DHSVM is appropriate for catchments with highly variable hillslope responses, such as Oak Creek.
DE: 1803 Anthropogenic effects (4802, 4902)
DE: 1847 Modeling
SC: Hydrology [H]
MN: 2007 Fall Meeting