Using GIS for facilitating Sediment Yield Estimation

摘要

The soil erosion from land areas can significantly causes damages to the terrestrial habitat and also has serious environmental impacts. In this study the Geographic Information System (GIS) combined with the sediment yield model can enhance the evaluation of soil erosion estimation. Geographic Information System with the Modified Universal Soil Loss Equation (MUSLE) was used to estimate sediment yield on a Ebbanad watershed of Lower Bhavani Catchment, Nilgiris district, India. Spatial data from different sources provided input for the factors in the MUSLE and from 20 years (1981 ― 2001) of rainfall records the storms were identified for determining the sediment yield estimation. The study watershed comprises of 29.2 per cent of annual cropping, 37.3 per cent of perennial cropping and 17.6 per cent of reserve forest. The drainage area, drainage network, slope and aspect were extracted from Digital Elevation Model (DEM) prepared from Survey of India toposheet at 1:50000 scale using IDRISI-32 GIS software. The surface runoff was under predicted for some of the storms and over predicted for some others. A sediment yield map of Ebbanad watershed from GIS predicts the degrees of erosion areas. The sediment yield was observed to be minimum in the range of 0 ― 2 tons on Reserve forest and Perennial crop areas for all the storm events and on an average between 4 to 20 tons from annual crop areas.