GIS BASED ON IDENTIFICATION OF POTENTIAL RUNOFF SITES IN MAROODIJEEH CATCHMENT, SOMALILAND

Abstract

Somaliland is a pastoral community with minimal water resources relying on rainwater and groundwater. The recurrent drought effects on Somaliland, specifically on the Maroodijeeh region, are rising due to climate change. Thus, surface water management's necessity becomes essential to resolve the frequent food crisis, increase the required production, and contribute to food and nutrition security and build local communities resilience. This study's main objective is to estimate surface runoff and find proper regions for runoff collection based on the physical properties like watershed through practicing GIS besides MultiCriteria Evaluation (MCE) as the mechanism for result support. The curve number (CN) procedure of soil conservation service (SCS) was employed. GIS was applied to generate a hydrologic soil map and the land use/land cover map, which were then intersected to create the CN value map. Runoff was then evaluated for the whole area using rainfall data according to the SCS-CN method. Different layers used for the multi-criteria evaluation are land use/cover, soil, slope, rainfall data, and drainage network. The soil conservation service model evaluates the study area's runoff depth. Analytical Hierarchy Processes (AHP) applied to determine proper runoff harvesting sites based on rainfall. The weighted linear combination (WLC) method integrates these physical models in this paper. Implementing the WLC covers the following of the propriety maps: • Setting. • Selecting the weights of relative significance. • Combining the importance and standardization. The results show that suitable sites with maximum runoff depth values are encountered in the upstream catchment. From the comparison study result, most surveyed points described as suitable (53.8%) were followed by highly suitable (38.4%), and only 7.7 % are in unsuitable areas. The area results explain that the database and methodology worked for improving the suitability model, including the propriety levels of the models and the models' relevant importance weights, provided good results.