Thesis
Large-scale simulation of the effects of climate change on runoff erosion following extreme wildfire events
Washington State University
Master of Science (MS), Washington State University
2013
Handle:
https://hdl.handle.net/2376/100196
Abstract
Across the western U.S., there is clear concern for increases in wildfire occurrence, severity, and post-fire runoff erosion due to projected climate changes. The first objective for this study is to advance the capability to simulate post-fire runoff erosion at scales larger than a single hillslope to examine the relative sensitivity of erosion to wildfire and climate change. The second objective is to advance the scientific understanding of the interactions between climate, hydrologic processes, fire severity, and post-fire erosion. The Variable Capacity Infiltration-Water Erosion Prediction Project (VIC-WEPP) model, a newly-developed physically-based modeling framework combining large-scale hydrology with hillslope-scale runoff erosion, is applied over the Salmon River Basin (SRB) in central Idaho. Rather than implementing WEPP over all hillslopes within the SRB, a representative hillslope approach is applied. For future scenarios, only meteorological impacts on post-fire erosion are considered; changes in future fire occurrence or burn severity are not incorporate. The assessment compares pre- and post-fire sediment yields from the VIC-WEPP model with a web based tool that uses a similar approach, Disturbed WEPP Nash Sutcliffe efficiency values over the SRB for VIC modeled simulated streamflow over the calibration (evaluation) period are 0.88 (0.83) and 0.96 (0.93) for daily and monthly time steps, respectively. Streamflow results show an earlier shift in peak flow by one to two months for future climate scenarios. Timing of peak flow shifted to earlier in the season by an average of 26 days for all average future streamflow fire severity conditions. The magnitude of peak flow increased by an average of 18% immediately after each increase in simulated fire severity. For yield change due to wildfire, individual model grid cells range from 0 t ha-1 to 927 t ha-1 . The range of yield change for climate change for individual model grid cells is -227 t ha-1 to 111 t ha1 . Large magnitudes of yields are mainly driven by cropland distributions and yields occur most frequently during rainfall on snowpack conditions. Results indicate that impacts on yield change from extreme wildfires are greater than impacts from climate change while climate change has important potential on erosion variability
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Details
- Title
- Large-scale simulation of the effects of climate change on runoff erosion following extreme wildfire events
- Creators
- Gregory Kenneth Gould
- Contributors
- Jennifer C. Adam (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Civil and Environmental Engineering, Department of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900524803901842
- Language
- English
- Resource Type
- Thesis