CS(AR)-23/07-98 : Estimation of sediment yield and runoff from small watershed using WEPP model

Abstract

The USDA Water Erosion Prediction Project (WEPP) model is a continuous simulation model developed to predict soil loss and sediment deposition from overland flow on hill slopes, soil loss and sediment deposition from concentrated flow in small channels, and sediment deposition in impoundments. In addition to the erosion component, it also includes a climate component which uses a stochastic generator to provide daily weather information, a hydrology component which is based on a modified Green-Ampt infiltration equation and solutions of the kinematic wave equations, a daily water balance component, a plant growth and residue decomposition component, and an irrigation component The model computes spatial and temporal distributions of soil loss and deposition, and provides explicit estimates of when and where in a watershed or on a hill slope the erosion is occurring so that conservation measures can be selected to most effectively control soil loss and sediment yield.

In this study, WEPP Model is used to estimate the sediment yield and runoff from Sallopat watershed located within Mahi river basin, which is having a geographical area of 38.4 sq.km. Hill slope and Watershed versions of the model have been tested. Simulated rainfall data for 25 years was used for the analysis and the average annual sediment yield from the watershed is estimated as 4333 Kg/m and the average annual runoff at the outlet is estimated as 317 mm.