WRD Halts Mamallan Reservoir Work Near Vada Nemmeli for Design Review

Work on the Mamallan reservoir project near Vada Nemmeli, planned as Chennai's sixth drinking water source, has been temporarily halted by the Water Resources Department (WRD). The pause comes as the department reviews design differences and assesses the site following recent rainfall.

The WRD clarified that the project has not been shelved. Work will resume after a high-level committee of senior officials submits its report and recommendations, which will address technical issues as well as concerns raised regarding flooding risks and the impact on local fishermen's livelihoods.

The review was triggered after differences were detected among designs prepared by various WRD wings, including the Design Research and Construction Support wing. In addition to internal reviews, Anna University has been engaged to validate the designs and offer recommendations, particularly regarding the project's coastal impact. The WRD plans to incorporate these technical findings into the final project plan.

The foundation for the ₹342.60-crore project in the Kovalam basin was laid in January 2026. The reservoir is planned across 5,161.27 acres and is designed to provide an annual storage capacity of 1.65 thousand million cubic feet (tmcft).

Since its announcement, the project has faced opposition over environmental and livelihood issues, including potential damage to coastal wetlands, biodiversity loss, and local flooding. Construction originally began following multiple assessments, including a third-party environmental study.

According to department sources, approximately 10% of the project work has been completed so far. The WRD's policy note for 2026-27 indicates that out of an assessed annual yield of 2.97 tmcft, about 1.65 tmcft is earmarked for Chennai's drinking water needs. The remaining flow is designated for release into the Muttukadu and Kokkilamedu estuaries to maintain ecological balance in the area.