DEM Spatial Resolution Impact On Hillslope Erosion and Deposition Modeling, an Application On Lebanese Watersheds

Abstract

Geographic Information Systems analysis based on Digital Elevation Models (DEMs) vary with spatial resolution and datasets production method. DEMs with different spatial resolutions can lead to several analysis results. This study investigates the effects of DEMs on predicting soil erosion and deposition modeling on Lebanese river basins. Two DEMs at different spatial resolutions from two sources were used to calculate topographic and hydrological parameters for the prediction of the Sediment Transport Index (STI), the erosion-deposition based on Unit Stream Power Erosion and the Deposition Model (USPED) taking into account only the topography factors expressed in DEMs.

This paper analyzes hillslope erosion and deposition rates in a GIS to estimate patterns sheet and rill erosion in 13 Lebanese river basins. A correlation analysis applied to test the degree of similarity between the datasets and the effect of erosion deposition with spatial resolution.

Results indicate that rill erosion and deposition have an influence on high spatial resolution DEMs, due to the good terrain representation especially the concave forms of deposition.

This result shows the increased rill erosivity of channel ?ow in the downstream, and sediment deposition in concave areas.