The Kerala government has also made a fresh request for a comprehensive and technically valid safety study of the 130-year-old Mullaperiyar Dam, citing the differences in previous technical assessments and pointing to the Supreme Court's direction for a fresh review.
The state’s chief engineer for interstate water matters has sent a detailed note to all six members of the independent supervisory committee appointed by the Supreme Court to undertake a comprehensive safety evaluation of the dam.
The move comes weeks after the committee visited Mullaperiyar in the first week of September. Kerala is now asking the panel to investigate the dam’s safety issues in more detail before it publishes its report.
Kerala raises questions over previous safety assessments.
Kerala cited the Supreme Court’s 2022 order, which asked the panel to address the safety concerns of the dam and carry out a fresh safety review when it discussed these issues with the committee.
The state said the last safety evaluation of the Mullaperiyar Dam was done in 2011. Kerala also has concerns over the methodology and findings of previous technical assessments.
According to the latest submission, the state has highlighted differences between findings attributed to IIT Roorkee and assessments carried out by the Central Water Commission (CWC). Kerala has also pointed to variations between different CWC assessments conducted at different points in time.
The state has argued that such differences require the safety evaluation to be examined again with detailed technical evidence and a comprehensive assessment.
According to committee chairman Balraj Joshi, Kerala had been assured that the state’s concerns would be taken into account. But a government official said there had been no communication and the latest submission came as the deadline for the committee’s report was closer.
Kerala questions 142-Foot rule curve
Another issue raised by Kerala is the rule curve of the Mullaperiyar reservoir.
A rule curve defines the level of reservoirs allowed at different times and under different conditions. Kerala has again raised its objection to the necessity of setting the maximum level of the rule curve to 142 feet.
The state has insisted the decision does not include the 2018 floods. The issue is important given that reservoir levels and flood-management procedures are very much part of the dam’s safety assessment.
The latest demand comes amid a long-standing dispute between Kerala and Tamil Nadu over the Mullaperiyar reservoir. Kerala has always claimed that the ageing dam is unsafe and has also supported the construction of a new dam.
Fresh Safety Evaluation Already Underway
The current safety assessment is a result of the Supreme Court order in 2022. In September 2026, a six-member panel headed by former NHPC chairman Balraj Joshi started its comprehensive evaluation at Mullaperiyar.
The assessment is intended to cover the hydrological, seismic and structural safety of the dam. The panel visited the main dam, Baby Dam, earthen dam and spillway in September, and representatives from Kerala participated in the process.
Kerala had earlier suggested that the panel strictly adhere to the terms of reference set in August 2025. State officials raised concerns about hydrological safety, structural safety, seismic safety, and seepage. The state also wanted detailed testing and examination of the site rather than just a brief inspection.
A detailed underwater analysis of the structure had already been carried out in December 2025 with a remotely operated vehicle to assess its structural integrity.
The committee will submit its findings in the prescribed time period. Kerala’s latest bid attempts to address the technical differences and concerns raised by the state before the safety evaluation is completed.
The Mullaperiyar issue is still linked to dam safety as well as Tamil Nadu’s water needs. The ongoing assessment is therefore being closely watched by both states as the Supreme Court-appointed process moves forward.
