Effect of DEM resolution on SWAT outputs of runoff, sediment and nutrients

Abstract

Digital Elevation Models (DEMs) have been successfully used in a large range of environmental issues. Several methods such as digital contour interpolation and remote sensing have allowed the generation of DEMs, some of which are now freely available for almost the entire globe. The Soil and Water Assessment Tool (SWAT) is a widely used semi-distributed model operating at the watershed level and has previously been shown to be very sensitive to the quality of the input topographic information. The objective of this study was to evaluate the impact of DEMs generated from different data sources, respectively DLG5m (local Digital Line Graph, 5 m interval), ASTER30m (1 arc-s ASTER Global DEM Version 1, approximately 30 m resolution), and SRTM90m (3 arc-s SRTM Version 4, approximately 90 m resolution), on SWAT predictions for runoff, sediment, total phosphor (TP) and total nitrogen (TN). Eleven resolutions, from 5 m to 140 m, were considered in this study. Results indicate that the predictions of TPs and TNs decreased substantially with coarser resampled resolution. Slightly decreased trends could be found in the predicted sediments when DEMs were resampled to coarser resolutions. Predicted runoffs were not sensitive to resampled resolutions. The predicted outputs based on DLG5m were more sensitive to resampled resolutions than those based on ASTER30m and SRTM90m. At original resolutions, the predicted outputs based on ASTER30m and SRTM90m were similar, but the predicted TNs and TPs based on ASTER30m and SRTM90m were much lower than the one based on DLG5m. For the predicted TNs and TPs, which were substantially sensitive to DEM resolutions, the output accuracies of SWAT derived from ASTER30m and SRTM90m could be improved by down-scaled resampling, but they could not improve on finer DEM (DLG5m) at the same resolution. This study helps GIS environmental model users to understand the sensitivities of SWAT to DEM resolution, and choose feasible DEM data for environmental models

Impact of precipitation and temperature changes on hydrological responses of small-scale catchments in the Ethiopian Highlands

“…A more detailed description of the model is given in various reviews of its performance and parameterization in Ethiopia and other regions (Schuol and Abbaspour 2007, Stehr et al 2008, Lin et al 2010, Setegn et al 2010, Betrie et al 2011, Tibebe and Bewket 2011, Mbonimpa 2012, Koch and Cherie 2013, Gessesse et al 2014). …”

Comparing CFSR and conventional weather data for discharge and soil loss modelling with SWAT in small catchments in the Ethiopian Highlands

“…620) was used to assess the impact of different rainfall patterns on run-off and soil loss dynamics through the ArcSWAT interface (Version 2012.10_1.14). Here, we present the SWAT model only briefly, as it has been widely used in the past, with an extensive review of its performance and parametrization in the United States, China, Switzerland, Kenya, Ethiopia, and other countries (Gessesse et al, 2014;Mbonimpa, 2012;Betrie et al, 2011;Tibebe and Bewket, 2011;Lin et al, 2010;Stehr et al, 2008;Schuol and Abbaspour, 2007). SWAT is a physically-based river basin or watershed modelling tool.…”

Assessing the Accuracy of SRTM Dem and Aster Gdem Datasets for the Coastal Zone of Shandong Province, Eastern China

“…This will enable us to better understand the associated vulnerability and risks and determine our responses to the risks. A high precise DEM is also required for hydrological studies [1,11,28], glacial mass loss assessment [14], orthorectification of satellite images [27], vegetation cover studies [18], and spatial dataset construction (e.g., gridded surface temperature and stable isotopic composition over Antarctica) [25,26]. In general, DEM data sets can be created by means of ground survey, photogrammetric techniques, radar altimetry, radar interferometry, and stereoscopic pairs.…”