T. Ramakrishnan

2,415 checkdams and 255 percolation ponds planned

CHENNAI: The Tamil Nadu Water Supply and Drainage (TWAD) Board, which depends heavily on the groundwater to run its water supply schemes, is taking up a Rs.130-crore project for building recharge structures in different parts of the State.

As part of the project, 2,415 checkdams, 255 percolation ponds and 580 recharge trenches/pits will be constructed over three years.

For the current year, the Board has been sanctioned Rs. 25 crore. It has released Rs. 19.5 crore to the field units for inviting tenders.

The project is part of a programme proposed by the State Ground and Surface Water Resources Data Centre (SG&SWRDC) of the State government.

The data centre prepared the master plan for the programme, whose cost is estimated to be Rs. 565 crore. The Water Resources Department, the Agriculture Engineering Department and the Forest Department are the other implementing agencies. The data centre is the nodal agency. A TWAD Board official says the plan is to construct as many recharge structures as possible before the northeast monsoon sets in. According to the master plan, 1,200 structures will be built in the first year (2008-2009); 1,000 in the second year; and 1,050 in the final year (2010-2011). The sites have been selected on the basis of work done by the Board, with satellite imageries and the geographic information system. A sum of Rs. 12 crore has been provided for maintaining these structures.

The official says the Board constructed 3,366 recharge structures, near the sources of water used by the agency, during 2001-2007. It has been monitoring the groundwater table. The rise ranges from 7.9 metres in Tiruvannamalai district to 1.5 metres in Nagapattinam.