Delineation of Groundwater Potential Zone in Foothill of Western Himalayan State Indian Journal of Ecology (2021) 48(6): 1685-1691 Manuscript Number: 3432 NAAS Rating: 5.79 Abstract: The present study emphasizes on the integrated remote sensing and GIS approach for delineation of the groundwater potential zone in foothill situated between Northern latitudes of 30°52' to 31°04' and Eastern longitudes of 76°40' to 76°55' falling in the Survey of India Toposheets no. 53A/12, 53A/16, 53B/9 and 53B/13. The thematic maps of influencing parameters viz. LULC, slope, geology, drainage, soil, aspect and lineament were prepared in Arc GIS. By integrating the information derived from the maps five zones having high, high to moderate, moderate, moderate to low and low to poor groundwater potential were distinguished. The overall results showed that maximum region came under high and moderate groundwater potential zone. Potential zones were further validated with 15 locations (hand pump and bore well) which, were randomly selected in the study area. Plotting of these points on groundwater potential zone map revealed that maximum points fell in high groundwater potential zone and one point was found in moderate groundwater potential zone thereby verifying that, zone I identified by remote sensing analysis was the zone holding maximum groundwater potential. This study will help policy makers in making appropriate water conservation strategies for the actual groundwater potential zones in the study area. Keywords: Groundwater, Remote sensing, Potential zones, GIS Pravidhi Sharma, R.K. Aggarwal and S.K. Bhardwaj Department of Environmental Science, Dr Y S Parmar University of Horticulture Forestry and Nauni, Solan-173 230, India E-mail: vidhusharma461@gmail.com Groundwater, which is one of the world's most precious and significant natural resource for the sustenance of life is controlled by geological and meteorological factors (Hutti and Nijagunappa 2011, Biswas et al 2012). Over the years, increase in population, urbanization and expanding agriculture has raised dependency on this valuable natural resource which is further expected to increase in future and the requirement in 2050 is estimated about more than three times to the present level due to increase in population (Gupta and Deshpande 2004). The groundwater is the largest available source of fresh water lying beneath the ground and has become crucial not only for targeting of groundwater potential zones, but also monitoring and conserving this important resource. Of the 37 Mkm of 3 freshwater estimated to be present on the earth, about 22% exists as groundwater, which constitutes about 97% of all liquid freshwater potentially available for human use. In India, 65% of the total geographical area is covered by hard rock formations and occurrence of groundwater in such rocks is essentially confined to fractured and weathered horizons (Saraf et al 2007). Therefore, an extensive hydrogeological investigation is required for thorough understanding of the groundwater conditions (Pandey et al 2013, Singh and Pandey 2014). To maintain the water table condition in balance and to restrict the surface runoff going waste, various measures for artificial groundwater recharge can be implemented in such zones. Till now, several conventional methods such as geological, hydro-geological, geophysical and photo-geological techniques are employed to delineate groundwater potential zones (Srivastava and Bhattacharya 2006) but these methods are very costly and time- consuming. Remote sensing with its advantage of spatial, spectral and temporal availability of data covering large and inaccessible areas within short time has become a very handy tool in assessing, monitoring and conserving groundwater resources. In recent years, extensive use of satellite data along with conventional maps and rectified ground truth data has made it easier to establish the baseline information for groundwater potential zones (Chowdhury et al 2010). GIS is considered as a powerful tool in integration and analysis of multi-thematic layers in delineating groundwater prospect and deficit zones (Ganapuram et al 2009, Selvam et al 2012). Several workers have used GIS techniques to delineate groundwater potential zone (Owolabi et al 2020, Ayyandurai and Venkateswaran 2021). Singh et al (2017) also conducted a study for delineation of the groundwater potential zone in Shimla city area and Suryabhagvan (2017) in the Bata river basin Himachal Pradesh using GIS technology. The Nalagarh valley is delimited between the Siwalik Hills with northeast (NE) and Sirsa river in southwest (SW). Sirsa River is the main river that flows through the central part of the Nalagarh valley.