干旱区生态环境知识资源中心

The Oil and Natural Gas Corporation Limited (ONGC), India, embarked upon exploration and exploitation of deep groundwater under the project named as "Saraswati" in arid Thar desert, Rajasthan, with a societal mission of providing water to the local people and cattle. A 555 m deep well drilled by the ONGC near Jaisalmer town in 2006 encountered a potential aquifer at a depth of 450-500 m. Radiocarbon dating of this well water indicated paleorecharge to be > 40,000 yr BP (uncorrected) (Before Present with respect to 1950 AD), while the medium depth (similar to 200 m) well waters around that area showed an age range of similar to 9,000 to 17,000 yr BP (uncorrected). These waters represent pre-Saraswati era recharge, because the mighty Saraswati flowed in this region between 7000-4000 yr BP. The stable isotope (delta D and delta(18)O) and Total Dissolved Solids (TDS) data of these waters clearly indicated absence of communication between the two aquifers (deep and medium depth). However, the extension of this deep aquifer needs to be determined.