South Dinajpur district lies in the Latitude between 260 35' 15" N and 250 10' 55" N Longitude between 890 00'30"E and 870 48' 37" E in northern portion of West Bengal State. The district forms part of Garo- Rajmahal gap and has typical combination of older alluvium (including Barind tract) and Recent alluvium. Coarse to fine sand and gravel forms the principal aquifers. Ground water occurs under unconfined condition in northern part, whereas in semi-confined to confined condition under a clay blanket in the Barind tract. In the tract, the aquifers are fine grained and thinner alternating with thick clay beds. The mode of withdrawal of ground water is through through dug well, shallow tube well fitted with submersible pump and deep tube well (Medium duty) are feasible for irrigation purposes. In the remaining part of the district shallow tube well and heavy duty tube wells are in use. Drinking water demand is fulfilled by hand pump fitted small diameter tube well and through piped water supply from medium duty or heavy duty tube well in city area. Dug well numbers have been decreased at present and used for domestic purposes mainly. Heavy duty tube wells use for irrigation purposes is tapping the aquifers within the depth range of 250 meter below ground level (m bgl). The district consists of 8 blocks, of which 5 are having high fluoride content (>1.5 mg/l) in ground water. Sporadic occurrence of fluoride has been observed in the tube wells. The fluoride content in ground water is increasing with depth in and around the Barind tract. The medium duty hand pump fitted tube well in the tract has.>5mg/l fluoride content, whereas in deeper aquifer fluoride content is as high as >10 mg/l. As the district has diversified hydrogeological set up, ground water management options to be considered with utmost care. In Barind tract, ground water potential is low and drawdown is high. Hence, scope of ground water development is limited in the tract. In older alluvium, dug well, light and medium duty tube wells fitted with submersible pump can be constructed for drinking and irrigation purposes with due care of the capacity of the pump to be used, so that drawdown can be minimized. Heavy duty tube wells should be constructed within the 250 m bgl depth and restricted drawdown to be maintained. In Recent alluvium, both shallow and deep tube wells are feasible and having very good ground water potential for development.
