VI-8-Geoelectrical Investigations and their Correlation with Groundwater Depth and Quality in Kaithal District of Haryana.

Abstract

The present study was carried out to investigate broad hydrogeological conditions by identification and characterization of the aquifer formations in terms of expanse and depth in Kaithal district of Haryana state. Vertical electrical soundings (Schlumberger array) were performed with maximum current electrode spreading of 400 m. Two layer curve matching method and IPI2WIN software were used to interpret and correlate the field data with some existing borehole columns. Thickness and resistivity values of various subsurface layers were determined. Geoelectrical sections Were prepared from apparent resistivity sections and interpreted quantitatively. Further, spatial distribution of average resistivity up to a depth of 200 m in the district was mapped in Geographic Information System (GIS) environment using ILWIS 3.6. The results were correlated with spatial distribution of depth to water level below ground level (bgl) and electrical conductivity of groundwater. The overall resistivity values were found to be directly proportional to depth to water level and inversely proportional to electrical conductivity (EC) of groundwater. A high average resistivity zone (65-130 ohm-rn) was prominent in Gulha, and Siwan blocks — the fresh quality area with very deep water table (30-45m). Medium resistivity zone (30-65 ohm-m) was found to cover Ghaggar area of Gulha block and parts of Siwan, Kaithal and Pundri blocks where depth to water table was in deep category (20-30m). Again, low resistivity zone (15- 30 ohm-m) was found in parts of the district at shallow depths. In the remaining low lying part in southern region having shallow groundwater depth in 3-10 m range and a high EC in 2500-9000 pS/cm range respectively, the average resistivity was found to vary in 0-15 ohm m range. Entire Pundri block along with a part of the adjoining Kaithal block (about 32% of total area) can be identified as the zone of good groundwater prospects. Western part in Siwan block (about 8% of total area) was found critical due to fast depleting levels.