Prioritization of micro watersheds on the basis of soil erosion hazard using remote sensing and geographic information system

Abstract

Degradation of agricultural land by soil erosion is world wide phenomenon leading to loss of nutrient-rich surface soil, increased run off from more impermeable subsoil and decreased water availability to plant. Thus estimation of soil loss and identification of critical area for implementation of best management practice is central to success of soil conservation programme. In this study universal soil loss equation (USLE) interactively with raster-based geographic information system (GIS) has been applied to calculate potential soil loss at micro watershed level in the Konar basin of upper Damodar Valley Catchment of India. The main advantage of the GIS methodology is in providing quick information on the estimated value of soil loss for any part of the investigated area. The rainfall erosivity R-factor of USLE was found as 293.96 and the soil erodibility K-factor varies from 0.325 - 0.476. Slopes in the catchment varied between 0 and 83% having LS factor values ranging from 0 - 6.7. The C-factor values were computed from existing cropping patterns in the catchment and support practice P-factors were assigned by studying land slope. Average annual soil erosion at micro watershed level in Konar basin having 961.4 km2 areas was estimated as 1.68 t/ha/yr. Further, micro watershed priorities have been fixed on the basis of soil erosion risk to implement management practices in micro watersheds which will reduce soil erosion in Konar basin.   Key words: Remote sensing, soil erosion, geographic information system, universal soil loss equation, priority.