AN IDENTIFICATION AND EVALUATION OF MAJOR GULLY EROSIONS IN ANKPA, KOGI STATE, NIGERIA

Abstract

This study was based on identification and evaluation of major gully erosions in Ankpa, Kogi State Nigeria using geotechnical investigation, field survey and rainfall information. This was done with a view to identifying the causes and extent of erosion in the area of study such that amongst other things, the erosional features occurring in the study area could be assessed, the soil characteristics could be examined and the threat the gullies pose to the settlement, structures and farmlands in the study area could be estimated and some technical remedial actions applied. The geotechnical method was employed to determine the grain size distribution of the soil, natural moisture content, plastic limit, while the field survey method was employed to determine the geomorphology of the study area like gully site locations, elevations, longitude and latitude, average widths, approximate depths and gully cross - sections. The results of this study indicate that the study area has high elevation which makes water to run down the slope with high velocities thus washing soil particles down to the streams and rivers. Also, the poor vegetation cover due to bad farming practice coupled with unconsolidated sandstone nature of the study area makes it prone to erosion. To control erosion in Ankpa area, proper environmental and land use management polices should be initiated at all levels and some technical remedial actions applied such as the check dams, shelter belts and vegetative barriers as these would check the causes and mechanisms of land erosion in Ankpa area