Morphometric analysis for prioritizing sub-watersheds and management planning and practices in Gidabo Basin, Southern Rift Valley of Ethiopia

Characterization and prioritization of watersheds has gained importance for proper planning and management of natural resources in sustainable development. Implementation of management practices over a larger area at the same time is inaccessible and uneconomical. So, it has required applying a viable technique for prioritization of critical sub-watersheds. Thus, the present study was aimed to prioritizing erosion-prone sub-watersheds using morphometric analysis. Advanced space-borne thermal emission and reflection radiometer of 30m resolution DEM has used to generate drainage networks and delineation of sub-watersheds using ArcGIS software. The important derived morphometric parameters have computed on the base of already developed mathematical formulae and methods. The study area (a watershed) has classified into seven interesting sub-watersheds, which have ordered SW1-SW7. The very important quantitative watershed aspects such as linear, relief and areal have been taken in consideration, and eighteen morphometric parameters have been selected and used for ranking and prioritizing of sub-watersheds. In this regard, sub-watersheds (SW7, SW3 and SW4) and (SW5, SW6 and SW2) have categorized into higher and medium priorities, whereas sub-watershed (SW1) has assigned at lower priority. This implied that SW1 is relatively sustainable than others, on the contrary, SW7 is relatively affected sub-watershed by runoff and soil erosion that needs first priority for management practices. Therefore, the study proposes a useful soil and water conservation practices such as bunds, check dams, micro-basins and multipurpose tree species planting based on suitable location and design parameters. The decision makers should optimally allocate the investments according to this final priority. And it has required to monitor and evaluate due to environmental sound, economical viable and socially acceptable. Also it has required developing an integrated approach for characterizing and prioritizing of sub-watersheds.