Abandoned quarries to be tapped in mid-February; private wells also on radar

The water crisis this summer may be a lot worse than the one in 2017, when the State experienced one of its worst droughts in 140 years.

According to Metrowater officials, the four lakes that supply water to the city have a storage level that is just 10% of their capacity. The water will last a little over a month.

Rains have failed to replenish the city’s reservoirs for three years in a row and managing the crisis could be tough as groundwater sources too have depleted unlike in previous years, officials said.

The release of Krishna water by Andhra Pradesh, which has helped tide over crises in the past, remains elusive so far. Though any inflow would be inadequate to see the city’s residents through the summer months, officials added.

Supply cut

Metrowater has now reduced its drinking water supply by 100 million litres a day (mld) from the 650 mld supplied last month to ration the fast-depleting resources, according to official data.

This has impacted piped drinking water supply in areas like Mogappair, T. Nagar and Mylapore.

However, Metrowater officials claim that the water situation is not alarming as of now and the number of tanker lorry trips remain at 6,300 daily.

With the city running out of water sources, Metrowater has started work to restore its infrastructure to draw water from abandoned quarries in Sikkarayapuram near Mangadu.

A 4.5-km-long pipeline from the Sikkarayapuram quarries to the Chembarambakkam treatment plant will be put to use again to draw water from the buffer source after a 15-month pause.

Once the infrastructure is in place, the water agency is likely to draw water in mid-February. Initially, about 30 mld will be drawn from the quarries.

Contingency plan

The water agency has lined up several other measures as part of its contingency plan to tackle the crisis.

Tenders have been floated for drawing water from private agricultural wells in Poondi, Minjur and Tamaraipakkam well fields. Similarly, bids are in process for sinking nine borewells of 400 mm diameter in the Gadilam river basin in Cuddalore district.

A Metrowater official said: “We will be able to sustain the present supply till March. Water supply from the Veeranam tank will last for another three months. Other water sources will be used only during peak summer.” Grey water recycling would play a major role in sustaining water supply in the future, he added.

Meanwhile, projects to construct onsite water treatment plants in Retteri, Perumbakkam and Ayanambakkam lakes, to use tertiary treated waste water and to build infrastructure to transport water from 12 quarries in Erumaiyur have been delayed.

The water agency has called for retenders as there were few takers, sources said.

On the dip in water supply across the city, officials said some areas may experience alternate-day supply or supply once in three days, depending on the source and distribution infrastructure.

For instance, Mogappair will have dwindling supply as levels in Chembarambakkam lake have dipped.