Hypsometric Analysis of the River Digil Catchment in Mubi Adamawa State, Nigeria

Hypsometric analysis as a method of evaluating erosion proneness of river catchment areas has gained wider popularity in recent time. Assessment of the stage of evolution of a landscape is a necessary prerequisite for landuse planning, natural resources conservation and management. The main data for this study was Shuttle Radar Topography Mission-Digital Elevation Model (SRTM-DEM) downloaded from the USGS Earth Explorer Portal. The GIS Extensions-Arc Hydro was used to process the DEM and the derived digital layer was used to delineate the River Digil catchment. The Elevation–Relief Ratio method was adopted to analyse the hypsometric integral of River Digil catchment and its sub-basins. Results of the analyses revealed that the study catchment and its sub-basins are in the mature or equilibrium stage of geological development. The hypsometric integral value of the River Digil catchment was 0.48, implying that 48% of the original rock mass in the study area is still intact. This indicates that the River Digil catchment has attained a stable stage in erosional processes. There was little variation in hypsometric integral values among the five sub-basins, which values range from 0.47 to 0.49. The findings of this study provide additional information to stakeholders involved in planning for soil and water resources conservation in the study area. This study recommends the construction of reservoir upstream of the River Digil catchment to impound excess surface runoff for urban water supply and to mitigate the problem of soil erosion in the downstream sector.