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In this study, the data generated while conducting electrical resistivity surveys through Vertical Electrical Sounding (VES) at six random sites in different location along with available geological & hydro-geological information of parts of Gwalior city were analyzed. The objectives are (i) to understand the nature and extent of aquifer, (ii) to find out the location and thickness of unsaturated zones and (iii) to evaluate the possibility of appropriate artificial recharge structures at suitable locations across the city.
Interpretation of the sounding curves indicates presence of three to four subsurface geo-electric layers across the study area. The top soil layer has a range of resistivity values from 2 to 30-ohm m & lithologically comprises clay / clay with kankar, lateritic sand. This is followed by the weathered and jointed shale layers with resistivity values 30-100-ohm m. A third layer of hard and compact shale with resistivity values 100–300-ohm m could be identified below a depth of about 45 m. At some places, doleritic dykes were also observed with resistivity values > 300-ohm m.
The interpretation of VES data when correlated with the available litholog data indicates a prominent water bearing zone between 30 and 45 mbgl. The underlying hard and compact shale has very little possibility of occurrence of ground water. The top unsaturated and unconfined granular zone up to a depth of 30 mts could therefore be easily recharged artificially through rainwater harvesting measures, thereby augmenting the groundwater resources of the existing aquifers. Site specific artificial recharge measures from amongst contour bundings, gully plugs, check dams, percolation tank, recharge shafts & subsurface dykes have been identified across the city for effective recharge of the aquifer especially in its north eastern (Morar block) & southern regions. Considering the deteoriating groundwater situation, these initiatives would be significant in catering to the needs of the future generations.
rainwater harvesting, artificial recharge (AR), vertical electrical sounding (VES), well-siting, ABEM terrameter –SAS 300, litholog, morar shales, schlumbger configuration
The author is thankful to Mr. V D Dubey, Ex-Unit Manager, AFPRO Regional Office, Gwalior (M.P) for providing me opportunities to carry out the geophysical surveys at many locations of Gwalior under various project assignments and valuable time to time suggestions during analysis & interpretation of generated data, which constitutes an important aspect of this research paper. The author would like to express his sincere gratitude to Mr. Sandip Kumar Mukherjee, Technical Director & Head–Environmental Engineering Department, M. N Dastur & Co (P) Ltd., Kolkata for providing me time & opportunity along with valuable guidance and encouragement for publicizing my ample work experience of Gwalior through this research paper. The author also expresses his gratefulness to Dr. Chinmoy Chakraborty, Retd. Addl. Director General, Geological Survey of India (GSI) and reviewers from publication house side for their critical comments, suggestions & editorial support.
AR Artificial Recharge
CGWB Central Ground Water Board
RWH Rain Water Harvesting
VES Verical Electrical Sounding
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