SC orders Info. on Rule Curve for “Mullaperiyar Dam”

What is the News?

The Supreme Court orders the Tamil Nadu Chief Secretary to give information on the ‘rule curve’ for the Mullaperiyar dam. It also directed the Supervisory Committee to issue directions or take steps to address the three core safety issues.

What is Rule Curve?

The ‘rule curve’ in a dam decides the fluctuating storage levels in a reservoir. The gate opening schedule of a dam is based on the ‘rule curve’. It is part of the “core safety” mechanism in a dam. Rules curves are used to guarantee the safety of the reservoir as well as water security.

About Mullaperiyar Dam:
  • The Mullaperiyar dam is located on the confluence of the Mullayar and Periyar rivers in Kerala’s Idukki district. The dam is located on the Cardamom Hills of the Western Ghats.
  • Operated by: The dam is located in Kerala but is operated and maintained by the neighbouring state of Tamil Nadu.
  • Why Tamil Nadu operates the dam? The dam is operated by Tamil Nadu following an 1886 lease agreement for 999 years. It was signed between the Maharaja of Travancore and the Secretary of State for India during British Rule.
  • Lease Agreement Renewed: In the 1970s, the lease agreement was renewed by Tamil Nadu and Kerala. It gave the former, rights to the water from the dam, besides the authority to develop hydropower projects at the site. In return, Kerala receives rent from Tamil Nadu.
Why Controversy over Mullaperiyar dam then?
  • In 1979, problems erupted over the safety of the Mullaperiyar dam. It was claimed that a minor earthquake had resulted in the cracks in the dam.
  • Consequently, the Central Water Commission decided that water level in the dam be brought down from the full reservoir level of 152 ft to 136 ft. It will enable Tamil Nadu to carry out dam strengthening works.
  • By the 1990s, Tamil Nadu started demanding restoration of the water level in the Mullaperiyar dam as it completed the task assigned to it. When no consensus was reached through negotiations, the Supreme Court was approached.
  • In 2014 as per directions of the Supreme Court, the Ministry of Jal Shakti constituted a three-member Supervisory Committee.
  • The committee has been asked to address the three core safety issues
    • Monitoring and performance of the instrumentation of the dam,
    • Finalising the ‘rule curve’ and
    • Fixing the gate operating schedule — and submit a compliance report in four weeks.

Source: The Hindu

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