Assessment Studies ofGroundwater Recharge in Nagamangala Taluk, Mandya District, Karnataka Using Remote Sensing and GIS Techniques

The groundwater recharge assessment studies in Nagamangala taluk in Mandya district were carried out based on geographical information system (GIS) and remote sensing techniques. In this connection satellite images (IRS-IA LISS+PAN+Wifs Image) and aerial plots were subjected to several treatment processes using software like ERDAS imagine and ESRI's Arc view. Thus, various thematic maps have been prepared for drainage density, lineaments, lithology and land cover/land use that allowed deciding their interactive effect. In the present study, the degree of effect was determined for each factor to assess the total groundwater recharge potentiality for two categories (moderate rate to low). The resultant map shows that 85% of the area has low and rest has moderate groundwater recharge potentiality. Finally, only 8.6% of the total average annual precipitated water (1685 mm) percolates into subsurface and ultimately contributes to recharge the groundwater.