Assessment of Basin Morphometric Measurements Accuracy Based on Different DEM Data, Chai Dakuk Basin, Northeast Iraq: A Case Study

Abstract

Morphometric analysis is essential in evaluating the geomorphological development and hydrological characteristics of rivers and valley basins. Several studies used different DEM data to evaluate elevation accuracy or their impact on measurements of limited morphometric parameters. The current study was carried out on the Chai Dakuk River basin in the northeastern part of Iraq. The basin is bounded by latitudes 34°44'30"- 35°35'49"N and longitudes 44°17'39"- 45°28'16"E. The current study aims to evaluate the accuracy of different DEM data, i.e., ASTER-GDEM 1-arcsec, SRTM 1-arcsec, and 3- arcsec, ALOS-12.5 meters, and GMTED 7.5 arcsec data, based on reference points collected by GPS and top maps of scale 1: 20000, and to evaluate DEM resolution on the calculation accuracy of different morphometric parameters. The analysis of morphometric parameters was carried out using ArcGIS- morphometric toolbox. The results of the accuracy assessment of DEM data identified the SRTM 1arc-second is more adequate with reference measurements; based on that, the measurements of all other DEM are compared to the SRTM 1- arcsec. The results of morphometric parameters show noticeable differences in many morphometric parameters calculated from different DEM data. Numbers and lengths of stream orders; bifurcation ratios; main channel length; drainage density; stream frequency; constant of channel maintenance; compactness coefficient; drainage texture; infiltration number; basin outlet height and the maximum height of basin, total basin relief, and ruggedness number. According to the results, the study concluded that the SRTM 1- arcsec data are more suitable for morphometric analysis, followed by ASTER GDEM data.