Özet:

Drainage basin/watershed analysis based on morphometric parameters has an essential role in watershed management and planning. Reliable delineation of watersheds and drainage networks is critical for hydrological and geomorphological studies. Since access to high-resolution digital elevation models (DEMs) and digital surface models (DSMs) is costly, many researchers need to evaluate low-resolution open-source products. Several data sources produced from different surveying techniques are used in the morphometric analysis. In this study, five different datasets such as Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) GDEM, Shuttle Radar Topography Mission (SRTM) DEM, Advanced Land Observing Satellite (ALOS) DSM, National Aeronautics and Space Administration (NASA) DEM, and a DEM from topographic maps (TOPO DEM), were investigated based on morphometric parameters. The tests was carried out in the Saz-Çayırova Basin, which is one of the critical urbanization and industrialization regions of Kocaeli, Turkey. In this study, the TOPO DEM, whose horizontal resolution is 30 m, was produced from 1:25K scaled digitized topographical maps. It was used for comparative analysis, as in all DEMs sources. The morphometric parameters' result of the TOPO DEM was used as the reference data for comparing the results of the other DEMs sources. In addition, the mean absolute percentage error (MAPE) was used to compute the accuracy between the freely available DEMs and the TOPO DEM for each morphometric parameter. The outcomes of this study reveal that the most consistent results with the TOPO DEM are provided by SRTM DEM, following the NASA DEM.

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