EAPSI: Understanding the pre-conditioning effects of solar radiation and precipitation on post-wildfire erosion

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Wildfire is increasing across the United States, and the hazards associated with fire do not end once the fire is extinguished. Burned soils are more susceptible to erosion than regular forest soils, therefore the first rains after a wildfire can generate catastrophic erosion. To predict where the most severe erosion will occur, we must understand how different soils erode after they are burned. This research will explore if landscape aridity (a function of precipitation and radiation) can be used as a predictor of post-fire erosion. This study will investigate if arid soil development on local patches of a mountain range will influence soil erosivity and if the preferential erosion of arid soils leads to mountain asymmetry over long time periods. The results could lead to better predictions of post-wildfire erosion. This research will be conducted under the supervision of Dr. Gary Sheridan, a global expert on the study of post-wildfire erosion, at the University of Melbourne in Australia. This research will use remote sensing imagery and topographic data to calculate the aridity index across a mountain range in Victoria, Australia. Mapping of the aridity index will effectively delineate where arid soils are likely to form. Fieldwork will involve measurements of soil properties in recently burned areas that were mapped as arid soils, which we will compare with samples obtained from non-arid zones. During the field campaign, we will test in-situ soil hydrologic properties by measuring the water infiltration capacity, the soil shear strength, and the total soil depth above bedrock in soil pits. Numerical modeling will be performed to determine how preferential erosion will effect long-term geomorphic hillslope evolution of a frequently burned landscape. This NSF EAPSI award is funded in collaboration with the Australian Academy of Science.