WATERSHED PRIORITIZATION FOR NATURAL HAZARD SUSCEPTIBILITY ASSESSMENT OF RIVER KILANGE BASIN, ADAMAWA STATE, NIGERIA.

BASHIR, B.A. AND IKUSEMORAN, M.

In this paper, geospatial techniques were adopted for the generation of morphometric parameters which were used to prioritize River Kilange Basin for natural hazard susceptibility. Shuttle Radar Topography Mission (SRTM) Digital Elevation Model (DEM) data of the basin was acquired on line and processed to generate seventeen sub-basins within the watershed. Twenty three parameters were obtained by using geospatial or quantitative techniques as appropriate for watershed prioritization. The twenty three parameters were grouped into five: drainage network, area parameters, watershed geometry, drainage texture and relief characteristics. The mean of the values that were obtained from each of the parameters in each sub-watershed were used to prioritize the watersheds for soil erosion and floods hazard into four classes; very high risk, high risk, moderate risk and low risk. The results revealed that the watersheds on high relief like Sanganare, Sensen, Song, Upper Kilange Giraba and Fa’ah were more prone to soil erosion. In contrast, those watersheds on low relief were found to be more vulnerable to flood. Hence, watershed on high relief fell under very high risk for soil erosion, while, those on low relief like Wuro De, Konchi, Upper and lower Lokko among others have higher priority for floods. It was recommended that constant monitoring and prioritization of sub-basins for effective watershed management should be periodically carried out for sustainable utilization and disaster risk reduction. The watersheds with higher priority in each of the two assessed hazards (floods and soil erosion) should be given more attention in the watershed management than those with less priority.

Key words: Kilange basin, Natural hazards, Morphometric parameters, Watershed prioritization.