Comparison of SRTM Data with other DEM sources in Hydrological Researches

The Shuttle Radar Topography Mission (SRTM) delivered a digital terrain model of better spatial resolution and accuracy than traditional free global DEM datasets at near-global coverage and made a wide range of detailed hydrologic applications feasible. In this study, the SRTM data is compared with the digitalized topographic contour DEM in hydrological analysis over the QingJiang catchment in HuBei province of China and a void patching method of SRTM for hydrological research is proposed. Drainage networks and catchment boundaries are generated with TOPAZ from both DEM datasets. The result shows that the voids in the raw SRTM dataset should be a big problem to hydrological analysis and the voids need to be treated carefully. The proposed void patching method can avoid the overestimation elevation values in drainage networks and make SRTM data more suitable to hydrological analysis.