IV-4-Estimation of Spatial Erosion using ANSWERS Model.

Abstract

Four major basic factors that influence runoff and soil erosion in a watershed are climate, soil properties, topography and land cover characteristics. These factors show large spatial variability across the watershed. The distributed parameter models can be best utilized to take spatial heterogeneity of a watershed into consideration. In the present study, ANSWERS, a deterministic and spatially distributed parameter model was applied for computing runoff and soil erosion from a small, hilly forested watershed in Nainital district of Uttarakhand state. Geographic Information System (GIS) techniques were used in the study to generate spatial information on slope, aspect, and land use properties. The results of the study indicated a satisfactory performance of the model in computing the surface runoff, peak runoff and sediment yield from the forested watershed. The model also computed the spatial distribution of soil erosion and deposition in the watershed. A comparative analysis of soil erosion under different canopy classes revealed that the erosion in C3 canopy < Cl canopy < C2 canopy in all the events. The average rate of soil loss from the watershed was found to vary between 17.52 to 151.77 kg/ha for the four events.