Applications of Erosion Hotspots for Watershed Investigation in the Appalachian Hills of the United States

Soil erosion, more than any other factor, has more significant and direct impacts on a hydrological watershed in terms of environmental problems. After deriving the erosion hotspots, this study used them to investigate two watersheds, Hocking River Basin and Atwood Lake Basin, in Ohio. Each watershed was divided into 30x30m grids, respectively, using the geographic information system (GIS), while the revised universal soil loss equation (RUSLE) was applied to estimate the soil erosion for each grid. Grid values of soil erosion estimates are ranked numerically from the lowest to the highest. Grids of soil erosion estimates equal to or greater than the top 5% value are defined as erosion hotspots to form the erosion hotspot image. Then, assigning individual parameters of land slope, soil type, and land use to be 1, to neutralize individual effects in the RUSLE modeling, three different erosion hotspot images were derived in a similar manner. Overlaying each of these three erosion hotspot images with the original erosion hotspot image, it was found that the land slope factor as a representative topography of the watershed has the most significant effect on erosion hotspots for both watersheds compared with soil types and land uses. Generally, the erosion estimate increases as the land slope increases, but the combination of soil type factor with land slope factor results in more effects on erosion hotspots in the Hocking River Basin than their counterparts in the Atwood Lake Basin. On the other hand, the combination of the land use factor with land slope factor has more effects on erosion hotspots in the Atwood Lake Basin than in the Hocking River Basin.