Current Science

N. C. Mondal ¹, S. Ahmed ¹

Affiliations
1 Aquifer Mapping Group, CSIR-National Geophysical Research Institute, Uppal Road, Hyderabad 500 007, IN

Abstract

Oozing of groundwater in Jodhpur city in the desert area of Rajasthan, India has caused weakening of foundations and cellars of buildings and shops. It has become more significant since 1996 when Kaylana lake was connected with Rajiv Gandhi Lift Canal (RGLC) water supply and filling of the lake had started. This has resulted in fear among dwellers about any future calamity. The hydrogeological, hydrochemical and isotopic studies clearly indicated that the lake water is responsible for the oozing phenomenon in the area. This article highlights a landscape entropy approach to assess pathways causing rise in the level of groundwater integrating the measured lake water level and groundwater table in a few selected wells in the city. With the fractional information of lake water and groundwater, marginal entropies of lake water and depths to groundwater in the selected wells sites are calculated. Mutual information, on common uncertainty associated in the measurements of lake water and groundwater, is also provided. Subsequently, ratios of mutual information to marginal entropy of the lake water are used as a measure for demarcating the pathways of weak zones, which correlate well with the lineaments delineated from satellite imagery. The results of this study represent a base for additional insight on future work, which will help in tracing the connectivity of weak zones causing oozing of water in Jodhpur city, and evolving a plan for remedial measures.

Keywords

Desert Area, Landscape Entropy, Marginal Entropy, Oozing of Water.

Full Text

   

N. C. Mondal ¹, A. Bhuvaneswari Devi ², P. Anand Raj ², S. Ahmed ¹, K. V. Jayakumar ²

Affiliations
1 Aquifer Mapping Group, CSIR-National Geophysical Research Institute, Hyderabad 500 007, IN
2 Water and Environmental Division, Department of Civil Engineering, National Institute of Technology, Warangal 506 004, IN

Abstract

This article aims to establish an empirical relationship among geoelectrical properties of aquifer and hydrogeological parameters to estimate its hydraulic properties, and reduce the processes of pumping test, which are costly and time consuming. A total of 19 Vertical Electrical Sounding (VES) data were collected using Schlumberger configuration in a granitic terrain in Tamil Nadu. The geographical parameters were analysed with IX1-D v.3 Interprex software. The pumping test conducted on nearby open wells was also used. A cross-correlation test was ascertained between hydraulic conductivity (K) and aquifer resistivity (ρ). It was found that hydraulic conductivity is best defined as an exponential function of aquifer resistivity. The field parameters, A = 20.235 and B = 0.012, of the function were optimized by using 'Solver', with the least SSQ (=7.82) and MARE (=0.816). It helped to estimate hydraulic parameters along with an empirical equation without pumping test data. The results emphasized the potential of surfacial resistivity survey in granitic area to determine aquifer properties where well information is not available.

Keywords

Field Parameters, Granitic Terrain, Geoelectrical Properties, Hydraulic Conductivity, Shallow Aquifer.

Full Text