WRD to study tapping floodwaters to meet Chennai’s water needs

CHENNAI: As the drinking water supply demand of Chennai is expected to be doubled in a decade from the present supply demand of 830 million litres per day (MLD), the state government has proposed to study measures required to be implemented to utilise floodwaters to provide additional supply to the city.

A Water Resources Department document said the government is initiating measures to counter the ill-effects of climate change on water availability through harnessing of floodwaters, conserving surface water and groundwater reservoirs, intra-transfer of water among the sub-basins, import of water from outside the Chennai basin, desalination plants and recycling of grey water.

Meanwhile, the department has decided to implement a project under the Chennai City Partnership programme, funded by the World Bank to combat flood and climate change and supply additional water to the city and conduct a study.

As a part of the study, strategies such as conservation of runoff water by forming new reservoirs, deepening and capacity addition to existing tanks, construction of barrages and check dams, augmentation of groundwater, reviving extinct water bodies, widening the rivers and channels, and connecting the hydraulically missing links were explored.

Presently, around 92 to 95 per cent of rainfall in the city goes to the sea as runoff water, leaving very little to percolate, mainly due to the rise in the concrete surface.

The Chennai catchment area is spread over 8,000 sqkm across Tamil Nadu and Andhra Pradesh. There are six sub-basins in Chennai catchment area such as Kovalam, Adyar, Cooum, and Kosasthalaiyar including Nagariyar and Nandhiyar, Araniyar and Gummidipoondi. The total project area covers 15,383 sqkm.