Steps: 1. Pre-processing Fill depressions Flow direction Flow accumulations 2. Stream definition (fig. a) Number of cells – 150 Areas – 0.015118 Km 2 2.

Catchment delineationProcess in creating sub-catchment polygons

Zhang

CAROLINA NORTH

Steps: 1. Pre-processing Fill depressions Flow direction Flow accumulations2. Stream definition (fig. a) Number of cells – 150 Areas – 0.015118 Km2

2. Stream segmentation3. Catchment delineation (Fig. b)4. Catchment polygons (Fig. b)

Fig. a) Stream

Fig. b) Polygons

Soil ErosionRelative Stream Power & Downslope Change

Zhang

Fig. c) Relative Stream Power (RSP)

Fig. d) Downslope change

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 slopeA measure of the erosive power of flowing stream network.

Relative Stream Power

Downslope change

Soil ErosionAnalysis of Downslope Change

Zhang

Fig. e) Selected catchments

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

Soil ErosionAnalysis of Downslope Change

Zhang