Chennai’s water needs to touch 2,236.5 mld by 2025, says study by Mahindra-TERI Centre of Excellence

The report titled ‘Water Sustainability Assessment of Chennai’ was released to mark World Environment Day

The shrinking waterbodies and reduction in catchment areas, due to expanding built-up area, poorly planned urbanisation and encroachments, would prove to be potential risks for water sustainability and result in increased intensity of floods.

The city’s water requirement will touch 2,236.5 million litres per day (mld) by 2025, considering the rapid increase in population and urban growth trend. This will require doubling the present water treatment plants’ capacity of 1,294 mld to match the growing demand.

This was one of the results of a report on ‘Water Sustainability Assessment of Chennai’ launched at a virtual meet to mark World Environment Day. At present, the water demand is estimated to be around 2,074 mld.

The study, which highlighted the potential water challenges in the Chennai Metropolitan Area, was carried out by the Mahindra-TERI Centre of Excellence, a joint research initiative of Mahindra Lifespaces and The Energy and Resources Institute (TERI).

With an analysis of various parameters, including population growth, changes in land use pattern and socio-economic character, the study identified potential risks associated with various aspects.

Going by the present urban growth trend, the report estimated that the built-up area was likely to increase to 708.3 sq.km in 2025, from 608.3 sq.km. in 2019, becoming three-fold of what it was in 1997. However, waterbodies would shrink to 38.4 sq.km by 2025, against 50.7 sq.km in 2019, which would be one-third of their coverage in 1997.

The shrinking waterbodies and reduction in catchment areas, due to expanding built-up area, poorly planned urbanisation and encroachments, would prove to be potential risks for water sustainability and result in increased intensity of floods. The unpredictable rainfall pattern, owing to climate change, could also bring in challenges of fluctuating water storage in reservoirs.

Similarly, the quantity of sewage generated was estimated to increase to 1,789.2 mld in 2025. There was a need to upgrade the sewage treatment plants’ capacity to 1,878.6 mld from the existing 727 mld as it would otherwise lead to more pollution of waterways, the study said.

Some key recommendations of the study were filling up data gaps related to groundwater availability, extraction and use by conducting detailed surveys; ramping up water infrastructure by way of water metering; strengthening pipeline and treatment capabilities; and adoption of water conservation practices such as rainwater harvesting and waste water reuse.

Highlighting various measures being taken to make the city more water-secure, T. Prabhushankar, Executive Director, Chennai Metrowater Supply and Sewerage Board, said the water agency was aware of the limitations. While the water sources available could yield 900 mld, the demand was 1,200-1,300 mld. Besides additional desalination plants and tertiary treatment ultra-filtration plants, Metrowater was also focussing on decentralised supply and demand management, he added.

Sanjay Seth, senior director, TERI, and Viral Oza, chief marketing officer, Mahindra Lifespace Developers Limited, also participated.