Evaluation of groundwater potential zones in the sub-watersheds of north pennar river basin around Pavagada, Karnataka, India using remote sensing and GIS techniques

The study area is one of the watersheds of North Pennar basin, covering an area of 570 km2 in Pavagada taluk of Tumkur district. The watershed has been subdivided into nine sub-watersheds namely Dalavayihalli, Maddalenahalli, Talamaradahalli, Puluvalli tank, Nagalamadike, Gowdatimmanahalli, Naliganahalli, Devadabetta and Byadanur. These nine sub-watersheds have been evaluated to delineate groundwater potential zones based on the characteristics of geomorphic units together with slope, geology, lineaments, borewell data using Remote Sensing and Geographic Information System (GIS) techniques. Slope varies from nearly level (0–1%) to very steep (>35%). The different geomorphic units in each sub-watershed consist of denudational hills, residual hills, inselbergs, pediment inselberg complex, pediments, shallow weathered pediplains, moderately weathered pediplains and valley fills. The lineament map for each sub-watershed has been prepared and the trends were analysed with rose diagrams. The analysis of borewell locations and their yield data in association with lineaments at subwatersheds level reveals that the lineaments are acting as a pathway for groundwater movement. The integrated map comprising groundwater potential zones prepared by “Union” function using GIS indicate that valley fills and moderately weathered pediplains are very good to good, shallow weathered pediplains are good to moderate, pediment inselberg complex and pediments are moderate to poor and denudational hills, residual hills and inselbergs are poor to very poor groundwater prospect zones

Morphometricanalysis of sub-basins in and aroundmalur taluk, Kolar District, Karnataka using remote sensing and GIS techniques

The study reveals that remote sensing and GIS techniques proved to be the competent tool in analysing various morphometric parameters.The drainage network of Kanamanahalli and Devaraguttahalli sub-basins were delineated using false colour composite (FCC) of IRS-1C/1D merged satellite data on 1:50,000 scale. SOI toposheets were used as reference with limited field work. The study area falls in Ponnaiyar river basin covering an area of 686 sq. km comprising two sub-basins namely Kanamanahalli and Devaraguttahalli having an area of 439 sq.km and 247 sq.km respectively in and around Malur taluk of Kolar district. The morphometric analysis of these two sub-basins shows that the terrain exhibits dendritic to sub-dendritic drainage pattern. Stream order ranges from first to sixth order. Drainage density varies between 1.57 and 1.88 km/km2 and has coarse to fine drainage texture. The relief ratio ranges from 0.0111 to 0.0117. The mean bifurcation ratio varies from 3.51 to 4.86 which fall under normal basin category. The elongation ratio shows that these sub-basins are associated with high relief and steep ground slopes