Mullaperiyar | 'No Amount Of Rejuvenation Can Perpetuate 126-Year Old Dam' : Kerala Seeks Reconsideration Of Rule Curve Adopted By TN For Water Level

Stressing on several aspects including the ageing of Mullaperiyar Dam and rapid rise in its water levels, the State of Kerala has pressed for reconsideration of rule curve prepared by Tamil Nadu to reckon the water level at Mullaperiyar Dam, before the Supreme Court.

The submissions have been made through a reply affidavit filed in compliance of Supreme Court's order dated 28.10.2021 directing the State of Kerala to file an affidavit, especially to deal with the issue on Rule Curve and about the current approach being adopted. 

State of Kerala has pointed out the following reasons for reconsideration of upper rule level of 142 feet formulated by the State of Tamil Nadu:

• The water level in the Mullaperiyar dam rises more rapidly if there is continuous heavy rain for one- or two-days during monsoon season
  
• Recent incidents of heavy rainfall in the State of Kerala, specifically in the catchment of the Mullaperiyar dam particularly in 2018 and 2019 and consequent sudden surge in the reservoir levels.
• Projected change in rainfall patterns due to climatic change and its impact on floods
• Insufficient spillway capacity to discharge sudden inflow into the reservoir
• Limited capacity of the tunnels to divert excess water in case of an emergency.
• Inability of the Idukki reservoir to hold the flood waters in the event of a extreme flood during the monsoon.
• The looming colossal damage to life and property of the people living downstream in the event of occurrence of a disastrous event

No amount of rejuvenation enough for the 126 year old dam

The Kerala Government has also said in the affidavit that the 126 year old dam cannot be strengthened by repeated reinforcements.

"...no amount of rejuvenation by any means can perpetuate the 126 years old deteriorated Mullaperiyar dam. There is a limit to the number of years one can keep dams in service through maintenance and strengthening measures. All over the world, citizens, Governments and organizations have begun to review the safety of their dams as per modern  standards and design criteria. Many dams have already been dismantled or decommissioned in an attempt to allay the fears of the people living downstream and to ensure safety to their lives and properties".

The State of Kerala submitted that the only permanent solution for removing the eternal threat owing to the safety concerns of the 126 year old existing dam in Mullaperiyar and for protecting the safety of the lakhs of people living in the downstream of Mullaperiyar dam, is to build a new dam in the downstream reaches of the existing Mullaperiyar dam.

High Water Level will Result In Catastrophe Beyond Imagination

The State of Kerala has submitted that if the water level at Mullaperiyar is kept at a higher level, releases from it will be affecting the already filled Idukki reservoir.

Therefore, in worst case of a cascading failure of Mullaperiyar and Idukki, it will result in a catastrophe which is beyond imagination affecting the life and property of 50 lakhs of people residing below the Idukki dam.

The State of Kerala has therefore sought directions to the State of Tamil Nadu to implement a Comprehensive instrumentation plan as per guidelines of CWC and approved by Supervisory Committee at the earliest. 

Through an interim order dated 28th October 2021, the Supreme Court had issued directions that for the time being both State of Tamil Nadu and Kerala will abide by the water level notified by the expert committee.

The State of Kerala has submitted that they have been requesting the Government of Tamil Nadu to take necessary action to increase the discharge through the spillways and through the tunnel so as to maintain the water level as per the rule level.

However, even after increasing the discharge through the spillway, Tamil Nadu's efforts were not translating into maintaining the reservoir level at 138 feet on 31st October.

Further, the State of Kerala has alleged that the water level was maintained at 138.55 at 11.00 pm on 31.10.2021 which was above the upper Rule level proposed by Tamil Nadu and hence the State has violated the directions of the Supreme Court.

In the light of above,  The Kerala Government made two requests :

1. The rule curve prepared by Tamil Nadu in consultation with CWC is required to be reconsidered by the Supervisory Committee in line with the suggestion given by the Kerala

2. Considering the ageing of the dam and as the dam is situated in the Seismic Zone III, issue directions to the State of Tamil Nadu to implement a comprehensive instrumentation plan for the dam.

The Kerala Government had earlier filed a statement before the Top Court objecting to the decision of the Supervisory Committee to not change the upper water level, and raising apprehensions about the safety of the masonry dam built 126 years ago using lime and surkhi. Kerala said that the logical step will be to decommission the dam and construct a new one.

A Bench led by Justice Khanwilkar has been hearing two writ petitions filed by Kerala based parties seeking urgent directions to restrict the water level in the 126 year old Mullaperiyar dam, which is being managed by the State of Tamil Nadu for drawing water to its districts.

(Cases : Dr.Joe Joseph and others versus State of Tamil Nadu and others(WP(c) No.880 of 2020), Suraksha Public Charitalbe Trust versus State of Kerala and others (SLP(c) No.3924/2021).