CHENNAI: Abandoned quarries in Sikkarayapuram whose collective capacity exceeds even that of Kannankottai Thervoykandigai, one of the five lakes that supplies drinking water to the city, may be identified as a backup drinking water source for Chennai that goes dry once every few years, a recent report says.
As per the ‘Feasibility Assessment of the Adaptive Re-Use of Resource Depleted Quarries in Kancheepuram District’ report prepared by Care Earth Trust on behalf of Department of Geology and Mining, three abandoned quarries in Sikkarayapuram and Mel Ayanambakkam that spans 38.46 hectares can hold approximately 600 Mcft of water. On the other hand, Kannankottai Thervoykandigai lake has a total storage capacity of only 500 Mcft, and as of January 29, it has 422 Mcft of water.
A field irrigation channel from Chembarambakkam lake collects runoff from the surrounding areas during rains before draining into the quarry pits. Thus the pits have water up to the brim, the report added.
As part of the assessment, the expert team of the Care Earth Trust visited the quarries before and after the monsoon, Jayashree Vencatesan, trustee of Care Earth Trust, said.
“Abandoned quarries should be restored as multifunctional habitats by including surface recharge, rainwater harvesting, greening and other aspects. Priority should be given based on the surrounding population. If there is an agrarian community nearby, quarries should be developed for irrigation,” she suggested.
The report also explained as there is a scope for the quarries to get filled up to ground level from the runoff almost every year, the use of the quarry pits for drinking water will ensure water supply to Chennai even during summer. Although the other quarries in Kancheepuram district store water, those quarries have bedrock bottom.
Following the report, the Kancheepuram district administration has decided to fence the quarries using Green Fund available with Mining department.
Meanwhile, an analysis carried out by the Trust a few months ago, before the monsoon, had estimated a storage of 495 Mcft in three quarries.
The WRD had created a drain from Chembarambakkam lake to the quarries to store surplus water in the quarries. Meanwhile, the Metro Water had established interconnection between all the quarries and with the WRD drain. It drew water from the quarries in 2017, 2019 and 2023 when the city experienced drought, and created pumping arrangements in 2017. As per present arrangements, water from quarries will be transported to treatment plant at Chembarambakkam lake and then supplied to Chennai, in case of shortage.