Erosion risk mapping in Peruguda micro-watershed of semi-arid tropics of India using remote sensing and GIS

Soils of Peruguda micro-watershed, developed on geologically complex terrain under semi-arid tropical climate of Ranga Reddy district, Andhra Pradesh, India were studied for their morphological, physical and chemical characteristics with a view to map the erosion risk zones using Remote Sensing and Geographic Information System (GIS). Soils developed under seven physiographic units viz., mesa top, mesa shoulder, mesa side slope, mesa foot slope, rocky ridge, undulating plain and narrow to broad valley were mapped and 23 soil mapping units have been identified. The soils vary in depth, drainage, surface texture, pH and organic carbon. The study of land use/land cover indicates that about 44.2% area is under rainfed agriculture. Based on the image characteristics, soil and site characteristics and land use/land cover, four erosion classes have been identified in the microwatershed. The soils of side slopes of undulating plain, mesa shoulder, dissected valley fill as evidenced by the dark to light blue, yellow, white mixed tone covering 33.59% area of the micro-watershed is under the threat of severe erosion hazard while soil of mesa side slope, rocky ridge and narrow to broad valley, covering an area of 5.01%, is under very severe erosion hazard as evidenced by the dark blue, yellow and white mixed tone in the satellite imagery. The study indicates an amount of 8940.2 to 17812.4 tonnes of soil loss yr⁻¹ from the micro-watershed. The mapping of erosion risk zones using remote sensing and GIS in the microwatershed helped to identity high erosion risk zones, which needs more attention towards the protection and conservation of natural resources through suitable soil and water conservation measures.