ASSESSMENT OF SUB-WATERSHED FOR SOIL EROSION THREAT IN A SEMI-ARID REGION WATERSHED (BENNIHALLA) OF NORTH KARNATAKA USING MORPHOMETRIC ANALYSIS AND GEO-COMPUTATIONAL APPROACH

Abstract Understanding the risks associated with soil erosion and drainage patterns is essential for agricultural output. In the research 9 sub-watersheds of the Bennihalla catchment located in semi-arid regions is studied to priorities for soil erosion-threat through morphometric investigation with the help of Geospatial methods and weighted sum approaches (WSA). ArcGIS was used to build drainage networks; SRTM DEM to delineate sub-watersheds and morphometric parameters (linear, relief and area) following standard formulas. The said parameters used to rank and prioritize sub-watersheds. A weighted sum approach (WSA) and cross-correlation of 18 morphometric parameters were used to approximate the compound factor. The compound factors for various sub-watersheds ranged from 0.0052 to 4.412. Lowest compound factor was given the highest priority. Sub-watersheds were classified as very good, good, moderate, low, and very low according to their compound factor value. The results indicated that, SW1 and SW 9 are influenced by respectively lowest and highest soil erosion threats, the other sub watershed that also need. Soil conservation measures include. SW7, and SW5 (1980.67 km2 area).