Evaluation of Erosion-Prone Areas in Lamurde River Basin, Nigeria Using Morphometric Prioritization Method

Abstract

Remote sensing and GIS techniques have been increasingly used in characterization of drainage basin and prioritization of erosion prone watershed. This study uses remote sensing and GIS to characterise drainage basin morphometry and prioritize soil erosion prone sub watershed in the Lamurde watershed in Taraba state Nigeria. The study adopted standard formulae and methods to compute the morphometric parameters. The Lamurde watershed was delineated to fifteen sub-watersheds with each coded as WS1 to WS15. The result of the findings reveals that Lamurde watershed has a dendritic to sub-dendritic drainage pattern with the smaller streams intersecting the main trunk at acute angles. The findings reveal that Lamurde is a ninth order stream with total area of 1,458.66 km2 and a perimeter of 395.93 km. The basin also has 258,493 total number of streams. The main soil types in the Lamurde basin are fluvisol, lithosol, ferric luvisols and humic nitosols. The surface soil texture of the area is mainly loamy type and particle size classes are fine loamy type. Depth of soil varies from shallow to very deep and having parent material derived from sandstones, mudstones and shales. The findings of the study reveals that watershed: WS7, WS8, WS5, WS11, WS15, WS14, WS2 and WS6 in ascending order are very highly vulnerable to soil erosion. Despite inherent limitation in the use of morphometric parameters to prioritize erosion prone sub watersheds, it is most suitable in the present circumstances because of inadequate information and lack of functional measurement station in the basin, since they have more stable and accessible data on which prioritization of the watersheds can be based on. This study contributes to the problem of dearth of information regarding the susceptibility to erosion in the Lamurde River Basin in Taraba State Nigeria. Based on this findings, these sub watersheds should be given higher priority on any soil conservation intervention measures in the study area. This will go a long way to help address the problem of soil erosion in the area.