COMPARATIVE EVALUATION OF EROSION HAZARDS IN IRELE L.G.A, ONDO STATE, NIGERIA USING EROSION MODELS.

Abstract

Some parts of Irele Local Government Area have been experiencing erosion, areas such as; Iyansan and Akotogbo, due to steep slope, which makes soil to erode from highlands to River Ebute located in the lowland parts of the study area. Gully erosion has become a death trap, in which homes, agricultural lands, ancestral lands, and economic trees have been lost. Therefore, the research was aimed at a comparative evaluation of erosion hazards in the study area, and the objectives were to: assess the factors causing erosion; map the erosion hazard zones using different erosion models; carryout a comparative analysis of the erosion models used; and propose possible solutions to reduce the impact of erosion in the study area. Three different erosion models which are; Revised Universal Soil Loss Equation (RUSLE), Modified Universal Soil Loss Equation (MUSLE) and Agricultural Non-Point Source (AGNPS), were used for assessing areas susceptible to erosion in the study area The erosion hazard maps produced from the aforementioned erosion models were classified into four different hazard categories, which were; low, moderate, high and very high. The results obtained from the three models showed that low hazard level had the highest spatial dimension of erosion with 452.09SqKm, 579.35SqKm, and 449.17Sqkm for RUSLE, MUSLE and AGNPS respectively. Areas such as Iyansan, Agbelebu, Akotogbo, Ubarogbo, and parts of Ago Bamuyegun and Ago Isobo, all fell within high and very high erosion hazard levels, which indicated that these areas were susceptible to erosion. In validating the results of hypothesis formulated for the study, it was observed that RUSLE and AGNPS are more reliable models for studying Erosion hazards in the Irele L.G.A. Therefore, proper awareness on methods to cub the effect of erosion, various land conservation practices (terrace planting, tree planting, crop rotation, afforestation, monitoring of grazing), and government support should be given to the affected communities.