DEM Aggregation and Smoothing Effects on Surface Runoff Modeling

Abstract

A digital elevation model (DEM) may be used in modeling direct surface runoff. Topographic variability affects the apparent slope and flow path length extracted from DEMS. Smoothing of the digital elevation data is a common procedure for reducing or eliminating pits prior to watershed delineation using a DEM. Error is propagated in simulations of direct surface runoff if the apparent slope is flattened or flow path length is shortened due to smoothing or aggregation of the DEM. Model error due to cell‐size aggregation from 30‐ to 90‐, 150‐, and 210‐m resolution and due to smoothing using a