Steps: 1. Pre-processing Fill depressions Flow direction Flow accumulations 2. Stream definition (fig. a) Number of cells – 150 Areas – Km 2 2. Stream segmentation 3. Catchment delineation (Fig. b) 4. Catchment polygons (Fig. b)

To measure the change of the slope, defined as the derivative of relative stream power. The higher the value is, the larger extent the stream power changes and thus the easier the soil erosion happens. RSP = As ^ 1.0 * tan(S) As: specific catchment area S: local slope A measure of the erosive power of flowing stream network. Relative Stream Power Downslope change

High values of dRSPdx: 33 catchments soil erosion are potentially to happen conifer Low downslope change: 94 catchments sediment are potentially to deposit impervious surface other land cover Catchment selection