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Effects of DEM Source, Spatial Resolution and Drainage Area Threshold Values on Hydrological Modeling

Munoth, Priyamitra, Goyal, Rohit
Water resources management 2019 v.33 no.9 pp. 3303-3319
Advanced Spaceborne Thermal Emission and Reflection Radiometer, automation, digital elevation models, drainage, hydrologic models, morphometry, processing time, runoff, sediment yield, watersheds
Automated computation of hydrological and morphometric parameters of any watershed are not only depended on Digital Elevation Model (DEM) resolution but also affected by their sources and drainage Area Threshold Value (ATV). In present study, the effects of different resolution of freely available DEMs are analysed in QSWAT model at different ATVs. The performance of QSWAT model and processing time were also evaluated. DEM derived from ASTER, CARTOSAT and SRTM were used at 30, 90 and 180 m spatial resolutions with six different ATV’s, in QSWAT model. Result shows that DEM resolutions and ATVs have significant impacts on hydrological and morphometric parameters. QSWAT output like sub-basin count and surface runoff were less impacted by DEM resolutions while these components were affected by ATV, while HRU counts and sediment yield were affected by DEM resolution. It was also observed that fine resolution DEM increases processing time at smaller threshold values as compared to coarser resolution DEM. Result of this study could be used for selection of optimum DEM resolution and ATV.