Prioritization of sub-watersheds for sustainable development and management of natural resources: An integrated approach using remote sensing, GIS and socio-economic data

The study area is one of the watersheds of North Pennar basin, covering an area of 570 km(2) and lies between latitude 13 degrees 55'-14 degrees 17'N and longitude 77 degrees 05'-77 degrees 25'E in Pavagada area, Tumkur District, Karnataka and a small portion in Ananthpur District, Andhra Pradesh, India, forming a part of the hardrock terrain. The drainage network shows dendritic to sub-dendritic pattern and is non-perennial in nature. Poor soil cover, sparse vegetation, erratic rainfall and lack of soil moisture characterize the area for most part of the year. Recurring drought coupled with increase in groundwater exploitation results in decline the groundwater level. The entire study area has been further divided into nine sub-watersheds, namely Byadanur, Devadabetta, Talamaradahalli, Gowdatimmanahalli, Naliganahalli, Nagalamadike, Maddalenahalli, Paluvalli tank and Dalavayihalli, ranging in geographical area from 49 to 75 km(2). It has been taken up for prioritization based on available natural resources derived from satellite images and socio-economic conditions, including drainage density, slope, water yield capacity, ground-water prospects, soil, wasteland, irrigated area, forest cover and data on agricultural labourers, SC/ST population and rainfall. On the basis of priority and weightage assigned to each thematic map, the sub-watersheds have been grouped into three categories: high, medium and low priority. The prioritization results reveal that Nagalamadike, Maddalenahalli and Dalavayihalli sub-watersheds rank highest on the basis of weightage and are considered as high priority. These sub-watersheds may be taken up with development and management plans to conserve natural resources on sustainable basis with immediate effect, which will ultimately lead to soil and water conservation.