Chennai Turns to Abandoned Quarries as Alternative Water Sources Amid Falling Reservoir Levels
A team of researchers, including experts from the Indian Institute of Technology Madras, is studying the feasibility of using abandoned quarries in Chennai’s southern suburbs to supplement the city's water supply. The initiative comes as storage in major reservoirs declines, renewing focus on alternative sources.
The study, funded by the Union Ministry of Science and Technology, evaluates nearly 25 quarries in areas such as Tambaram, Vandalur, Nallambakkam, Tiruneermalai, Unamancheri, and Keerapakkam. It aims to assess storage capacity, water quality, and the potential for linking these quarries to existing water supply networks.
Abandoned quarries are already part of Chennai’s drought contingency plan. Chennai Metrowater maintains a network of quarries at Sikkarayapuram and Erumaiyur as buffer sources, which are used when the Northeast monsoon is poor. These quarries currently hold about 75% of their combined capacity of 0.7 thousand million cubic feet.
Elango Lakshmanan, visiting faculty at IIT Madras’s Department of Civil Engineering, noted that quarries have a smaller surface area (0.3 to 0.5 sq km) compared to the Chembarambakkam reservoir (15 sq km), resulting in lower evaporation losses of 10%-20%. He recommended that water from the reservoir be used immediately after the Northeast monsoon, with quarries serving as secondary sources later in the year.
Meanwhile, Chennai has received increased Krishna water inflows from Andhra Pradesh, with flow reaching 312 cubic feet per second. Officials expect the inflow to rise to 500 cusecs in the coming days, helping maintain reservoir storage at nearly 47%.
Metrowater plans to draw water from the Sikkarayapuram and Erumaiyur quarries only if the Chembarambakkam reservoir dries up or the Northeast monsoon fails. The available storage can supply about 30 million litres per day from Sikkarayapuram for a year and 10 million litres per day from Erumaiyur for 425 days.
A proposal to link 25 quarries in Sikkarayapuram into a single storage structure is awaiting government approval. The study aims to develop a cost-effective network of alternative water sources to enhance Chennai’s water security.
