Modeling Post Wildfire Hydrology In The Western Us

Post-wildfire hydrology research and development efforts within the Post-wildfire Program at the US Army Engineer Research and Development Center include research on post-fire runoff generation mechanisms for enhancing the post-fire flood simulation capability of the US Army Corps of Engineers’ hydrological models. This study developed wildfire-induced soil hydraulic factors to account for the dynamic, hydrophobic intensity as a function of soil moisture content and burn severity, both identified at a grid / local scale. This method is implemented in the Gridded Surface Subsurface Hydrologic Analysis (GSSHA) model. The coupled model has been applied in several Western US watersheds to develop, test, and verify post-wildfire hydrologic / flooding assessments. The study watersheds include: (a) Upper Arroyo Seco and Haines Canyon watersheds after the 2009 Station Fire in CA, (b) Tule River watershed after the Windy Fire in CA, (c) watersheds in Santa Barbara and Ventura Counties after the 2017 Thomas Fire in CA, (d) Trapper Creek after the 2020 Badger Fire in ID, (e) Weiser watershed after the 2020 Wood Head Fire in ID, and (f) Detroit Lake watershed OR after several wildfire events in the last two years (Grandview Fire, Jack Fire, and the merged Beachie Creek, Lionshead, and P-515 Fires). The approach shows improved post-fire flooding extent and hydrograph simulations.