This summer, Chennai Metrowater’s well fields in Tiruvallur district will be rejuvenated after a gap of nearly a decade to tackle water shortage in the city.
The fast-depleting resources in the reservoirs, the major suppliers of drinking water to the city, have set the focus on well fields in Poondi, Tamaraipakkam and floodplains near Kosasthalaiyar river. Besides rejuvenating the 20 borewells in these well fields, the water agency plans to sink 16 more borewells to augment water supply.
The water agency recently called for tender to revive the well fields. At present, the four reservoirs in Poondi, Cholavaram, Chembarambakkam and Red Hills have a combined storage of 4,090 million cubic feet, which is 37 per cent of their total capacity. The supply from Veeranam tank in Cuddalore district and Krishna water from Andhra Pradesh too has been minimal for want of resources.
With surface water resources fast drying up, the water agency is now tapping the groundwater potential in its well fields in Tiruvallur district to sustain the drinking water supply of 831 million litres a day (mld). Some areas, including Sridevikuppam and Brindavan Nagar in Valasaravakkam and T. Nagar, are already complaining of low water pressure and reduction in piped water supply.
The water agency owns six well fields in Minjur, Tamaraipakkam, Panchetti, Poondi and Kannigaiper and floodplains in various areas along the Kosasthalaiyar river.
Of the over 60 borewells in these well fields, water is being drawn from only 20 borewells. Metrowater stopped extracting water from Panchetti and Kannigaiper and most parts of Minjur a decade ago as the yield had reduced. The water table has dipped in these areas as several farmers too use groundwater for agriculture. A limited amount of one to two mld is being extracted from the Minjur well field to provide water to industrial belt. Similarly, a negligible amount is being drawn from the southern aquifer along the East Coast Road.
Officials of Chennai Metrowater said about 20 mld of water would be drawn from the new borewells that would be sunk up to a depth of 100 feet.
“We take up regular maintenance of the borewells. But this work worth Rs. 4 crore will involve flushing of aquifer and also improving infrastructure for drawal,” said an official. The water extracted from the wells would be transmitted to the treatment plant in Poondi and then provided for drinking water supply.
“We plan to complete the work within two months to tackle water shortage this year,” said an official.