Silt accumulation at Pillur Dam and seepage at Siruvani threaten Coimbatore’s drinking water supply

Silt accumulation has led to 58% loss of storage capacity at Pillur dam.

| Photo Credit: SPECIAL ARRAGEMENT

More than 50% of the storage capacity of the 100-ft Pillur Dam has been lost to silt accumulation over the decades, while seepage at the Siruvani Reservoir continues to result in water loss, posing a challenge to Coimbatore’s drinking water supply.Corporation Commissioner M. Sivaguru Prabakaran said the Pillur and Siruvani schemes form the backbone of Coimbatore’s drinking water network and any reduction in storage or drawal capacity would directly affect water distribution in the city.Around 754 MLD of water is drawn from River Bhavani through 14 drinking water schemes catering to Coimbatore and Tiruppur districts. Of this, Coimbatore city alone draws around 277 MLD through three Pillur-based drinking water schemes located in the upstream and downstream stretches of the dam.Mr. Prabakaran said seepage in the Siruvani Reservoir remained a concern, with nearly 10 MLD of water being lost every day during the monsoon season. At full storage level, the reservoir supplies close to 100 MLD to meet the city’s drinking water requirements, with drawal declining as storage levels recede.He said the Corporation had given fresh impetus to desilting works at the Pillur dam, where around 58% of the storage capacity was lost to silt accumulation, and to seepage rectification works at the Siruvani reservoir, and had urged the State government to convene a joint meeting of the departments concerned to coordinate further action on the projects.The Commissioner said immediate intervention was necessary as silt accumulation at Pillur, seepage at Siruvani and declining storage levels posed a threat to Coimbatore’s drinking water supply, which is heavily dependent on the two reservoirs.He said the Kerala government was yet to accord final approval for the Siruvani repair works, following which the methodology for plugging seepage points would be finalised and implemented.The Siruvani reservoir has a water-holding capacity of 49.53 ft. In 2014, the Kerala Irrigation Department raised concerns over dam safety, following which the permissible storage level was reduced to 44.61 ft from the Full Reservoir Level of 49.53 ft.Mr. Prabakaran said the Water Resources Department had also proposed construction of another dam around 6 km downstream of the Pillur dam at a site with better storage potential. The proposal is in the preliminary stage. Published - May 29, 2026 11:45 pm IST