Mamallan reservoir work temporarily paused to validate project design

Sources say about 10% of the work on the ₹342.60-crore project in the Kovalam basin has been completed so far. | Photo Credit: M. SRINATH Amid reports that the work for the Mamallan reservoir, proposed as Chennai’s sixth drinking water source, has stopped, the Water Resources Department (WRD) said the work had been halted temporarily to review the project design and also due to rainfall at the site near Vada Nemmeli.The WRD clarified that the project had not been dropped, and work would resume after a high-level committee, which was formed to review the project, submitted its report and recommendations, including on concerns raised about the reservoir project such as flooding and impact on fishermen’s livelihoods in the region, said sources.There were differences detected in designs prepared by various WRD wings, including the Design Research and Construction Support wing. The high-level committee, comprising senior WRD officials, is likely to submit their report shortly. The report is expected to also cover technical aspects, including the project design and the project would incorporate its findings. Anna University has also been roped in to validate the designs and provide recommendations, including on the project’s coastal impact, sources said.It may be recalled that foundation for the ₹342.60-crore project in the Kovalam basin was laid in January 2026. It aimed to create a reservoir spread over 5,161.27 acres and an annual storage capacity of 1.65 thousand million cubic feet. The project ran into controversy and faced opposition from various quarters citing reasons including the loss of biodiversity and fishermen’s livelihood, flooding concerns, and damage to coastal wetlands. Work began after various studies, including a third-party environmental study.About 10% of the work has been completed so far, sources said. The WRD’s policy note for 2026-27 stated that of the annual yield assessed as 2.97 tmcft, nearly 1.65 tmcft would be stored for drinking water purposes and the remaining flow would be released into the Muttukadu and Kokkilamedu estuaries to maintain ecological requirements. Published - September 01, 2026 09:03 pm IST