WRD unveils Rs 14,000-cr plan to triple Chennai’s water storage by 2050 | Chennai News

By 2050, Chennai will need more than three times the drinking water storage it now has. To avert a potential crisis, the water resources department (WRD) has unveiled a 14,000-crore plan to restore lakes and tanks, and build new reservoirs and recharge structures.The WRD consultant, Royal Haskoning DHV, has prepared a detailed feasibility report projecting the city’s water storage demand to increase to 38.73tmc from the existing 11tmc. Of the 1,165 projects proposed by the consultant to meet this demand, WRD has approved 704 ‘essential projects’ that will be executed within the next 10 years.The works, spread across 12 basins, including Chennai and Palar, focus on restoring a chain of 350 tanks such as Thenneri, Sriperumbudur, Thirunindravur, Manimangalam, and Pillaipakkam, which are Chembarambakkam’s catchment sources. It also includes OMR’s chain of 64 tanks such as Narayanapuram, Thalambur, Semmenchery, and Nanmangalam.WRD superintending engineer M Magesh Nagarajan said restoring these tanks into mini catchments can enable storage of 0.25tmc to 0.5tmc per tank. “We plan to restore 1,150 tanks around city suburbs by deepening and bund creation with sluice gates to prevent entry of sewage, if any. Once restored, the neighbourhoods around the tanks will be self-sufficient and their reliance on major reservoirs will reduce,” he said.The department’s projection has not added a major boost to the capacity of the five existing reservoirs, but focuses on alternative sources. Twelve reservoirs will be built in upstream locations of three rivers: Cooum, Adyar, and Palar. Nagarajan said they have identified sites at Thiruverkadu and Poonamallee in Cooum and in four villages along the Palar. “Each reservoir will boost storage between 0.5tmc and 1tmc,” he said, adding that Chembarambakkam’s water will then become exclusive for the core city.Under the scheme, WRD will also execute three new reservoirs, including one at Salt Lake on ECR and another on a 300-acre ‘revenue poramboke’ land near the Tamil classical institute at Perumbakkam. “The Perumbakkam reservoir will enable storage between 1.7tmc and 2.25tmc, while the ECR site will give another 2tmc,” said Nagarajan. These, he added, will prevent drainage into Pallikaranai and hold water for OMR areas.WRD has also planned 402 groundwater recharge structures along river bunds by creating ponds alongside freshwater courses.T Kanthimathinathan, coordinator of water resource management, disaster management department, said the plan proposes to supply 500mcft from Kannankottai Thervaikandigai to neighbourhoods and industries. “Once the pipelines are laid, it will reduce the burden on major reservoirs. About 200 tanks inside industrial areas of Irungattukottai, Oragadam, and Pillaipakkam will also be restored. This will make industries self-sustaining and ease 115MLD of supply from Metrowater,” he said.Inter-basin linking will include diverting water from Adyar to Palar in the upstream and two intra-basin linkings from Kosasthalaiyar to Cooum through macro drains.Water experts welcomed the plan but stressed enforcement. S Janakarajan, president of the South Asia Consortium for Interdisciplinary Water Resources Studies, said the city is blessed with adequate rainfall year after year. “We have 4,100 lakes across four districts. We do not have to look elsewhere to store water,” he said.Sekhar Raghavan of Rain Centre said household-level compliance was crucial. “If we rejuvenate aquifers with freshwater and enforce rainwater harvesting, we do not have to rely on external supply or tankers,” he said.