strategy, known as GARDIT( General Aquifer Research Development and Investigation Team) strategy that aimed to deliver an increase in withdrawal of 70 million lit / day, using this water for public and private supply, and to bring G. W. levels under control. There has been a more rapid decline in G. W. levels in the central and southeast London than expected, caused restriction of withdrawal Govt. Chennai:
The Ground water problem in Chennai is opposite. Chennai is underlain by various geological formations from ancient Archaean to the Recent Alluvium. Ground water in Chennai district occurs in all the geological formations viz., the Archaean crystalline, Gondwanas, Tertiaries and alluvium. The crystalline rocks are weathered and jointed / fractured. The degree and depth of weathering varies from place to place and the thickness of weathered mantle varies from less than a meter to about 12 m in this district. The successful bore wells drilled tapping the deeper fractured aquifers in Saidapet, Adyar, Kasturba nagar, Gandhi nagar and Ashok nagar revealed the existence of fracturing down to depth of 60 m below ground level. The granular zones below the Kankar layer in the depth range of 20-28 m bgl in Poes Garden probably represent Tertiary sandstones and tube wells tapping these granular zones yield 2 to 3 lps. The C. P. R Environmental Educational Centre made a survey in and around Chennai city, and the results show that crisis in both water availability and pollution is worsening gradually with each day. On one hand, the quality of water is getting worse, and on the other hand, the level of water level is going down rapidly. Water samples from different locations were collected from wells and boreholes and analyzed for their portability. Total dissolved Solid( TDS) exceeded 500 mg / l( desired limit in drinking water) in 83 % of samples, and 72 % of samples contained more than 1000mg / l. About 38 % of samples contained more than 2000 mg / l of TDS, and 22 % of samples contained high level of iron content. Proper water resource management and rainwater harvesting may reduce the problem.
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Integrated River Basin Management Society