Comparative study of the drainage basin morphometry extracted from topographic maps and SRTM DEMs: an example from Ghadir watershed, Eastern Desert, Egypt | ||||
Delta Journal of Science | ||||
Article 2, Volume 39, Issue 2, December 2018, Page 52-64 PDF (2.93 MB) | ||||
Document Type: Research and Reference | ||||
DOI: 10.21608/djs.2018.138907 | ||||
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Authors | ||||
Mahmoud H. Ashmawy; Mohamed A. Abd El-Wahed; Samir Z. Kamh; Aly Shebl | ||||
Geology Department, Faculty of Science, Tanta University, Tanta 31527, Egypt | ||||
Abstract | ||||
The drainage network of Wadi Ghadir watershed, southeastern Desert, Egypt was extracted from topographic maps (1:50. 000), and from the 30 m digital elevation data (DEM) of the Shuttle Radar Topography Mapping Mission (SRTM). Four topographic sheets were digitized and used for extraction. Archydro function in ArcGIS 10x was utilized for network extraction and for morphometric analysis. Networks derived from topographic sheets and DEM were considerably coincident. Different morphometric parameters from both sources were evaluated to examine the accuracy of DEM for hydrologic applications. Results clarified 6th order streams for both drainage networks with moderate to high drainage density (D) of 2.51 km.km2 (topographic) and 2.54 km.km2 (DEM) reflecting that W. Ghadir drainage basin is impermeable with considerable surface runoff. DEM showed higher stream frequency (F) of 4.49 than those derived from topographic maps (4.38). Calculated bifurcation ratio (Rb) of streams derived from topographic sheets reached about 3.47 and about 4.60 for those derived from DEM. DEM-derived morphometric parameters provided good and satisfactory information about the catchment characteristics and revealed accurate watershed delineation confirming high potential of surface runoff of the W. Ghadir drainage basin. Finally, SRTM DEM proved advantageous over the topographic sheets for drainage delineation and basin morphometry for hydrologic analysis underpinned with the finer spatial resolution and the vertical accuracy. | ||||
Keywords | ||||
Topographic sheets; Morphometric; SRTM DEM; Ghadir watershed; Eastern Desert; Egypt | ||||
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