Kerala has expressed its strong dissent in a written note based on the interim order dated October 27, 2021, in which the Supreme Court directed Kerala to furnish the factum of rule curve and other matters/issues discussed recently in the joint meeting with Supervisory Committee on October 26, 2021 through Video Conferencing, stating that the rule curve prepared by Tamil Nadu is not acceptable to it for the following reasons:
1. According to the upper rule levels prepared by Tamil Nadu cannot be relied upon in these unpredictably climatic conditions.
2. The rule curve prepared by Tamil Nadu in consultation with CWC revealed two peaks at 142 feet on September 20th and November 30th, which the State of Kerala considers unacceptable.
3. There were also differences between the 10-day cumulative inflow data provided by Tamil Nadu to Kerala and the data used by Tamil Nadu to derive Rule curves.
4.The water level rises above 142 feet for more than 50 hours during the flood routing exercise. This means that MPD may not be able to maintain the water pressure for such a long time, jeopardising the dam's safety and undermining the Supreme Court's directive to keep the level at 142 feet.
Mullaperiyar Dam is a 126-year old composite dam located at an altitude of 2890 feet in the Western Ghats. Despite of measures taken, the dam is losing its strength and is deteriorating. The Kerala government objected to keeping the reservoir level high due to the age of the Mullaperiyar dam and its safety and the looming colossal damage to the lives and property of people living downstream of the Mullaperiyar dam in the event of a catastrophic event.
According to the report submitted by the Empowered Committee in 2012, the existing Mullaperiyar Dam (MPD) was found to be safe structurally, hydrologically, and seismologically for storing water up to 142 feet, and the Chairman and member representing Tamil Nadu agreed, to which Kerala disagrees.
"Ageing Water Storage Infrastructure: An Emerging Global Risk" is a UN report about unsafe dams that primarily mentions Mullaperiyar dam with details of supporting references stating that the dam is unsafe.