Sensitivity of Hydrological Outputs from SWAT to DEM Spatial Resolution

摘要

This research analyzes the sensitivity of the SWAT (Soil and Water Assessment Tool) flow rate and sediment yield to DEM spatial resolution. A scaling analysis is performed using 1 to 50 m resolution lidar (Light Detection and Ranging) derived DEMs. Thomas Brook, Canada, serves as a case study watershed for a five year simulation period. Results indicated monthly water yield was insensitive to DEM resolution, unless a change in area was also present. Sediment yield from the 50 m DEM showed a 200 t reduction compared to the 1 m DEM. The 5 to 50 m DEMs also showed a reduction in channel deposition of 45 to 90 t, respectively, compared to the 1 m DEM. Results suggest parameterization using multiple resolution DEMs is desirable, one commensurate with the scale used to establish universal soil loss equations for defining hillslope scale, and high resolution for stream network and sub-basin delineation