With its avowed mission of making Chennai a water-resilient city, the Water Resources Department proposes to augment water supply by conserving nearly 7.26 tmc ft of water and prevent flooding of several areas. It has submitted a detailed project report seeking World Bank funding under the Chennai City Partnership Programme.
The 17 projects chalked out by the department are set to address the twin issues of droughts and floods experienced by the city. The projects, with a combined outlay of ₹464 crore, will cover the Adyar, Cooum and Kosasthalaiyar river basins.
One of the key projects is to build a barrage across the Adyar near Thiruneermalai and provide headwork to pump water and transfer it to Chembarambakkam treatment plant, the reservoir or to the Sikkarayapuram abandoned quarries where water is stored for city supply.
Moreover, flood water from southern tributaries of the Adyar stored in Orathur reservoir and check dams across the river in Varadarajapuram and Somangalam would be linked to Chembarambakkam through this infrastructure. “We will be able to augment city water supply by up to 2 tmc ft through this project alone. The water pumped would be sent to Chembarambakkam or Sikkarayapuram through a 6.5-km-long pipeline,” said an official.
Based on the model study, the department planned to boost water supply and mitigate floods through various strategies such as intra-basin transfer, construction of barrages or riverine reservoirs, improving storage capacity of tanks and conservation of flood water in rivers.
For instance, construction of barrage across the Palar near Padalam-Udayambakkam and Chengalpattu would help conserve one tmcft of flood water and divert it for Chennai’s water needs.
Some of the dilapidated check dams in the Kosasthalaiyar and Cooum rivers, including in Velliyur and Sorancheri respectively, would be reconstructed for groundwater recharge. “We will be able to enhance groundwater potential and tap 180 million litres a day through well fields in the region near Kosasthalaiyar through the proposed projects,” another official said.
Moreover, restoring storage capacity of a cascade group of tanks, including Tiruninravur, Thandurai and Sekkadu, would help surplus water reach the water body in Retteri.