Tamil Nadu has engaged the Council of Scientific and Industrial Research (CSIR) and the National Geophysical Research Institute (NGRI), Hyderabad, to conduct a site-specific seismic study of the century-old Mullaperiyar dam, with the report expected to be submitted before December.
The engagement was made under Section 16 of the Tamil Nadu Transparency in Tenders Act, 1998, according to a government order. A senior state government official said Tamil Nadu would soon sign a memorandum of understanding with the two agencies.
The study is being carried out in accordance with directions issued by the supervisory committee constituted by the Supreme Court to monitor the safety of the inter-state dam. The official said the report would be submitted to the central comprehensive dam safety evaluation committee because Mullaperiyar is an inter-state dam.
The seismic assessment comes within the framework of the Dam Safety Act, 2021. The law requires the first comprehensive safety evaluation of every existing specified dam to be completed within five years of the Act coming into force. Subsequent evaluations are to be carried out at intervals prescribed under the regulations.
A comprehensive evaluation includes a general assessment of seismic safety. In specified cases, it also requires a study of site-specific seismic parameters. The current exercise is therefore focused on conditions specific to the Mullaperiyar dam and its location, rather than only a general review of dam safety.
The dam has been at the centre of a long-running dispute between Tamil Nadu and Kerala. Tamil Nadu has maintained that Mullaperiyar is safe from hydrological, seismic and structural perspectives, citing the 2014 Supreme Court judgment. Kerala has continued to seek the construction of a new dam, citing safety concerns for people living downstream.
The issue has previously involved expert studies and judicial oversight. In 2010, an empowered committee led by former Chief Justice of India A S Anand engaged the Central Water and Power Research Station in Pune to conduct a study of Mullaperiyar.
The latest assessment also follows Tamil Nadu’s decision in July to constitute an independent panel of experts for a comprehensive safety evaluation of 86 dams under the state water resources department. The panel includes experts drawn from a list empanelled by the National Dam Safety Authority, as well as serving and retired officials from central and state organisations.
Those evaluations are expected to examine hydro-mechanical systems, dam design, seismic safety, geology, hydrology and instrumentation. A state official said further studies would be undertaken based on the findings of the evaluations. The immediate milestone for Mullaperiyar is the completion and submission of the site-specific seismic report to the central comprehensive dam safety evaluation committee before December.
