Estimation of Soil Loss at Tehri Dam Catchment in Uttarakhand, India.

The soil erosion is the most serious environmental problem in watershed areas in Bhagirathi River. The main factors affecting the amount of soil erosion include vegetation cover, topography, soil, and climate. In order to describe the areas with high soil erosion risks and to develop adequate erosion prevention measures in the watersheds of dams, erosion risk maps should be generated considering these factors. “Reduction in the capacity and life of Tehri dam Reservoir was became a major concern. Remote Sensing (RS) and Geographic Information System (GIS) technologies were used for erosion risk mapping in the catchment area of Bhagirathi River. The principal aim of this paper is to utilize spatial-based soil erosion information to assess land suitability at a watershed level. The model integrated with RS and GIS technologies has great potential for producing accurate and inexpensive erosion risk maps.

Data on Climate (Total precipitation and its frequency and intensity), Geomorphology (Land form, Physiography, Slope and Drainage Characteristics), Soil characteristics (Texture, structure), Land Use/ Land cover (Density of forest or grassland, plant residue, crops etc.) and Soil management were calculated using standard reported methods (Naqvi et al., 2015). Total 6 parameters were calculated i.e. Slope, Slope length, Soil texture, Drainage density, landuse/landcover and Rainfall erosivity. Weightage of each parameters on the basis of value and classes were assign. At last SYI value were calculated using weightage map, Delivery ratio, area of watershed. The sub-watersheds 10, 11 were identified as being very high risk. Intense rainfall and reservoir area of dam coupled with poor soil structure and steep slopes are the main drivers of soil erosion in this area. Therefore, the proper designing of integrated watershed management and conservation strategies is a crucial element to reduce the current rate of environmental degradation and boost up agricultural production in the sub-watersheds.