Assessment of Morphometric Characteristics of Gojeb watershed, Omo-Gibe Basin, Ethiopia

Abstract

In this work, morphological features and basin characteristics of the Gojeb watershed, Omo-Gibe Basin, were identified and analyzed using GIS and image processing techniques. Watershed delineation and analysis of morphological features based on Shuttle Radar Topography Mission (SRTM) DEM data were performed using GIS hydrology tools. This study also assesses the sub-basins' morphometric metrics, such as area, perimeter, stream frequency, maximum width and length, drainage density, and stream orders, as well as their geometric characteristics. The results led to delineate nine sub-watershed with nine stream orders, the drainage density of these sub-basins are ringing between 0.75 to 0.99 km/km2. Stream orders were calculated, The outcomes allowed for the delineation of nine sub-watersheds with nine stream orders, having a drainage density of between 0.75 and 0.99 km2/km2. There are 1763 streams with a length of 941.26 km as the first order, 503 streams with a length of 307.09 km as the second order, 3755 streams with a total length of 1128.46 km as the third order, 1144 streams with a total length of 696.56 km as the fourth-order streams, and 519 streams with a total length of 425.86 km as the fifth order, 1284 streams with a length of 796.66 km as the sixth, 615 with a total length 429.69 km as seventh order, 873 with a total length 529.72 km as eighth-order streams, and 985 with a total length 708.38 km as ninth order. The stream length is greatest in the third order, and it gets shorter as the stream order gets higher. This finding may be helpful to regional planners and national decision-makers for agricultural and water management policies.