Drainage Morphometric Analysis of Shope watershed, Rift Valley, Ethiopia: Remote sensing and GIS-based approach

Abstract

The quantitative drainage morphometric analysis at the watershed level is essential for understanding its geo-hydrological nature. Drainage morphometric evaluation has been conducted to identify the predominant geological divergence, topographical details, structural arrangement, and interrelationship in the Shope watershed Rift Valley, Ethiopia. The Remote Sensing Data and Geographical Information System (GIS) tools have delineated the Shope Watershed and calculated various morphometric attributes. The Shope watershed exhibits a dendritic drainage pattern very clearly. The watershed’s drainage pattern also suggested that the region lacked geological structural control over the drainage pattern growth. Shope watershed is categorized as a 5th order drainage watershed. The bifurcation ratio ranges between 1.11 and 2.28 (with an average of 1.72) between various stream orders. Low bifurcation values area is more prone to flooding. Mean drainage length and length ratio values indicating the present study area’s undulating topography and steep slope. The Shope watershed’s circularity and elongation ratio values are 0.7 and 0.63. Both values indicate that the present watershed is elongated and has steep slopes, and more prone to erosion and flooding. The higher drainage density values 6.75 km/km2 indicating low infiltration and high runoff. The Shope watershed’s relative relief value is 1757 m, and this high value indicating the study area’s proneness to the flooding and soil erosion. The results of the current drainage morphometric analysis of the Shope watershed are essential for assessing and managing soil and water resources and selecting suitable sites for artificial recharge structures and soil conservation structures for future soil and water management in the present study area.