Runoff and soil erosion modelling for sustained development of land and water resources under watershed concept

Abstract

Runoff is the most important hydrological component for a design of any hydrologic structure and especially in the area of water scarcity. Soil erosion assessment is a capital-intensive and time-consuming exercise. A number of parametric models have been developed to predict soil erosion prone zone at structural terrains, even though Universal Soil Loss Equation (USLE), and it’s updated or modified versions are most widely used empirical equation for estimating annual soil Loss. Morgan, Morgan and Finney 1984 proposed a model on field base information and estimation had yielded point-based accuracy values.Watershed management or protection implies the proper use of all land and water resources for optimum production with minimum hazard to natural resources as watershed conservation planning. Therefore, it is necessary to study runoff and soil erosion simultaneously. This study demonstrated using MMF model that the rate of soil detachment (J) varied from 0.34 – 7.91 kgm-2, whereas the total average annual volume of runoff for the study area is around 94.9 mm. The estimated weighted average soil loss (G) at the outlet estimated by MMF model was 1.61 t ha-1 y-1. Hence, introducing appropriate interventions based on the erosion severity predicted by MMFmodel in the catchment is crucial for sustainable natural resources management.