A flow-direction model is based on surface elevations

and their spatial relationships (Fig. 3); a flow-accumulation model calculates the number of cells in the spatial flow-direction grid that connect (i.e. contribute flow) to a given cell (Fig. 4C). Higher numbers reflect larger drainage contributions from upstream/up-gradient regions. Channels are recognized as having extremely high pixel PARP signaling values as they are a point of cumulative surface flow convergence. Fig. 4C shows the locations of rills and gullies across the watershed (highlighted in dark blue with pixel values close or at 50). A cap of 50 was created for the flow-accumulation raster as this pixel value in the grid coincides with gully occurrence based on field reconnaissance. The original flow-accumulation raster contained values up to 100. All pixels affixed with values exceeding 50 are re-coded to have values of 50 so that processes dealing with gullying are unaccounted for in the model. Since gully processes are not accounted for, gully volume is calculated to offer insight into the amount of material potentially provided by gully formation. The final modified flow-accumulation raster accounting for the presence of gullies (Fig. 4C) and a slope raster (Fig. 4B) created from the USGS DEM (i.e. elevation grid; Fig. 4A) were combined to generate

the LS-factor for the Lily Pond watershed (Fig. 4D), which shows the inferred total topographic control on soil Apoptosis inhibitor erosion due to rill and inter-rill processes. Direct observations and sedimentologic evidence suggest that little to no material is stored within the gullies and that sediment derived from overland flow is washed into them during rain events and funneled directly Cobimetinib purchase into the pond (Fig. 3). Published information from USDA soil surveys and literature sources provide K-factors based on the spatial distribution of soils in the Lily Pond watershed. The Mahoning County Soil Survey ( Lessig et al., 1971) provides detailed

information on these soil types, whose spatial extents are shown in Fig. 4E. Soils of the Dekalb Series are recognized as light-colored, stony soils along valley walls that formed in loamy material derived from loosely bonded, medium- to coarse-grained sandstone. These soils comprise the steep hillslopes surrounding Lily Pond and are assigned a K-factor of 0.24 based on Hood et al. (2002). The hilltop to the NW of the pond and its steep surrounding slopes as well as a shallow-gradient area to the SW of the pond contain soils of the Loudonville Series, which are light-colored and occur where only a thin mantle of soil overlies till or bedrock ( Fig. 4E). The series members in the study area are classified as disturbed soils that have been affected by construction and development to some degree such as digging, logging, and grading operations ( Lessig et al.