oa Resistivity Soundings For Hydrogeologic Evaluation In Piedmont Region Of Jammu Siwaliks (India)

The submontane region of the Himalayas fringing the Siwalik hills of Jammu<br>Division of Jammu & Kashmir (India) is an extension of the Kandi belt in the States of<br>Himachal Pradesh, Punjab, Haryana, and Uttaranchal. The Kandi belt is a steeply sloping<br>tract of less than 10 to 30km width, which flattens downstream. Hill torrents contain<br>water only during freshets and run dry for most of the time. Vast stretch of boulders and<br>dry streambeds present a very dry look to this tract. Towards south and southeast of the<br>Kandi belt, undulating land with flowing stream and good agricultural ground presents a<br>green look. This tract is locally known as the Sirowal belt, equivalent of the Tarai in<br>other parts of the Himalayas.<br>The paper presents the results of a study, which covered the hydrogeological<br>evaluation of the southern part of Siwaliks in the Jammu region. The study describes<br>delineation of the thickness and water-bearing characteristics of the major geologic units,<br>and determining the groundwater potential in the area.<br>Based on the geology and aquifer characteristics, the piedmont deposits of Jammu<br>are classified into three hydrogeoelogical sub-units, namely Recent alluvium (of<br>Siwaliks), Kandi belt, and Sirowal belt. Groundwater in the Kandi area occurs under<br>water table conditions. The nature of sediments and disposition of the Kandi belt make<br>the zone of saturation lie at great depth in the Kandi. However, a perched water table<br>exists, seasonally, above the shallow fragipans. Groundwater in the Sirowal, however,<br>occurs under both water table and confined conditions. Deeper granular zones in the<br>Sirowal contain water under confined conditions. Transmissivity values in Kandi and<br>Sirowal belts range from 367-2613 m2/day and 110-1197 m2/day, respectively. Siwaliks<br>are considered to be poor aquifers.<br>Data of geoelectrical soundings in Sirowal and Kandi belts were used to explore<br>the groundwater potential. Total 136 geoelectrical soundings were used to cover an area<br>of 1,440km2 approx., with maximum spread length (AB) of 840m. Transverse resistance<br>was estimated from the sounding curves at various sites, and good correlation with<br>aquifer transmissivity was observed. Transverse resistance values were used to classify<br>the area into three groundwater development classes, which corroborated well with the<br>known groundwater potential at selected sites.