The Supreme Court on Thursday said the Supervisory Committee’s view to maintain the Mullaperiyar dam level at 139.5 feet till November 10 should be followed.

A Bench led by Justice A.M. Khanwilkar observed that the committee may review its opinion if the situation suddenly changed on the ground due to heavy rains, etc.

The committee, represented by Additional Solicitor General Aishwarya Bhati, stated it was monitoring the situation on an hourly basis.

The court scheduled the next hearing on November 11 at 2 p.m.

Backgrounder | Mullaperiyar: genesis of a dispute

Detailed affidavit

The Bench deferred the hearing after Kerala requested time to file a detailed affidavit in response to the committee’s views, especially with regard to ‘rule curve’, which means the level maintainable in the reservoir on different days.

The court directed Kerala to file its affidavit on or before November 8.

Appearing for Kerala, senior advocate Jaideep Gupta pointed out that the Northeast monsoon was about to begin and the reservoir level was expected to rise. “After that, it will be dangerous,” he submitted during a physical court hearing.

Annual ploy of Kerala: T.N.

Senior advocate Shekhar Naphade, for Tamil Nadu, countered that it was an annual ploy of Kerala to bring the level down from 142 feet, a height allowed by the apex court in its judgments. “Every year, Kerala attempts to bring it down from 142 feet,” he argued.

“The 139.5 feet suggested by the Supervisory Committee till November 10 will continue… We will see on the next date on November 11… Meanwhile, let the parties abide by the recommendation of the Supervisory Committee,” Justice Khanwilkar addressed both the States.

Kerala’s objections

Earlier in the day, Kerala submitted a note in the court raising objections against the committee’s recommendations on rules curves. The panel was against any drastic changes in the water level at the dam.

The State noted that a 126-year-old structure, held together by lime-surkhi and situated in a seismically active zone amidst torrential blasts of rains, was vulnerable. The structure and the danger of high upper rule levels posed a catastrophic risk to the lives and property of lakhs of people downstream.

The State, in a note filed in the court, pointed to the prediction of heavy rainfall till October 31. It had asked for a reduction in the dam’s maximum level to 139 feet rather than the court-approved 142 feet. It argued that a flood-routing exercise had seen the level rising above 142 feet for more than 50 hours.

“The Mullaperiyar Dam is a 126-year-old composite gravity dam situated at an altitude of 2890 feet above MSL on the Western Ghats. The hearting of the dam, which accounts for more than 60% of the volume of the dam, was constructed with lime-surkhi concrete. Quite understandably, seismic forces were not considered in its design. Presently, the dam is in deteriorating condition due to its age. There would be an exponential increase in the water pressure and uplift pressure acting on the dam when the water level is raised from 136 ft to 142 ft. (i.e. from 859.167 to 936.648 tonnes per meter length of the dam),” the note explained.

The consequences of any failure of this dam may be “beyond human imagination”. Tamil Nadu could take several measures to keep the water at a safe level without reducing its supply water availability. Instead of utilising the full outflow capacity of 2,735 cusecs at 137 feet, it was drawing only 2200 cusecs only till 5 a.m. as on October 27. It could create additional storage at appropriate places. The capacity of the Vaigai dam could be enhanced to store more water. The capacity of the existing tunnel could be enhanced or an additional tunnel constructed for drawing more water from the Mullaperiyar reservoir, it stressed.