DEM Study on Hydrological Response in Makkah City, Saudi Arabia

Abstract

The changes in catchments can be analyzed through the generation of DEM, which is important as input data in hydrologic modeling. This study aims to analyze the effect of anthropogenic activities on hydrological studies based on DEM comparison and GIUH hydrographs. The four DEM datasets (SRTM, ALOS, Copernicus, Sentinel-1) were compared to the topographic map of Makkah City and GPS data in order to assess the quality of the DEM elevation. The GIS Arc Hydro toolbox was used to extract morphometric and Horton–Strahler ratio characteristics to generate a GIUH hydrograph of the catchments of Wadi Nouman and Wadi Ibrahim inside Makkah City. Based on the DEM comparison, Copernicus and SRTM have the highest accuracy, with R2 = 0.9788 and 0.9765, and the lowest RMSE, 3.89 m and 4.23 m, respectively. ALOS and Sentinel-1 have the lowest R2, 0.9687 and 0.9028, and the highest RMSE, 4.27 m and 6.31 m, respectively. GIUH Copernicus DEM on Wadi Nouman has a higher qp and lower tp (0.21 1/h and 2.66 h) than SRTM (0.20 1/h and 2.75 h), respectively. On Wadi Ibrahim, the SRTM has a greater qp and lower tp than Copernicus due to the wadi having two shapes. Based on the anthropogenic effect, the stream network in the mountain area is quite similar for SRTM and Copernicus due to the dominant influence of the mountainous relief and relatively inconsequential influence of anthropogenic activities and DEM noise. In the urban area, the variation of the stream network is high due to differing DEM noise and significant anthropogenic activities such as urban redevelopment. The Copernicus DEM has the best performance of the others, with high accuracy, less RMSE, and stream flow direction following the recent condition.

Sustainability Evaluation of the Al-Qasab Playa by Integrating Hydrogeochemical and Graphical, ArcGIS Watershed, and Thermodynamic Geochemical Modeling Approaches

“…of a watershed, and this information is computed to derive the general character of the watershed. Recently, with the advancement of remote sensing and spatial technology, the computation of various terrain and hydro-morphometric characters of drainage basins was simplified [16,[25][26][27][28]. The digital elevation map (DEM) for the Al-Qasab region was downloaded from the Earth Explorer website from NASA's Shuttle Radar Topography Mission (SRTM) dataset with a resolution of 30 m [18].…”

“…It is generally plain, with an average altitude of 640 m above sea level. Recently, digital elevation model (DEM) data representing the elevation or topography of the earth's surface have been widely utilized for environmental studies, including catchment or watershed delineation and characteristics estimation, surface flow-path mapping, and stream network extraction [16,17]. DEM data are derived from remote sensing data collected by the National Aeronautics and Space Administration (NASA) missions under the Shuttle Radar Topographic Mission (SRTM) program, which provides near-global topographic coverage of the earth's surface with unprecedented consistency and accuracy [18].…”

The Synergistic Effect of Topographic Factors and Vegetation Indices on the Underground Coal Mine Utilizing Unmanned Aerial Vehicle Remote Sensing

“…First, data collection and contour line drawing are carried out, and then the contour line is used for data interpolation to generate the regular grid, to represent ground elevation. (2) The DEM is directly downloaded from the Geospatial Data Cloud ( , accessed on 24 December 2022) or other ways [ 26 ], which is widely used in existing studies, and its research scope is large (not limited to a mine). However, the DEM obtained by the first approach cannot accurately represent the true terrain structure, and this approach has complex data processing and a cumbersome workload.…”