From UPSC perspective, the following things are important :
Prelims level : Mullaperiyar Dam
Mains level : Not Much
Kerala plans to build a new dam to replace the 126-year-old Mullaperiyar dam in the Idukki district.
- It is a masonry gravity dam on the Periyar River in Kerala.
- It is located on the Cardamom Hills of the Western Ghats in Thekkady, Idukki District.
- It was constructed between 1887 and 1895 by John Pennycuick and also reached in an agreement to divert water eastwards to the Madras Presidency area.
- It has a height of 53.6 m (176 ft) from the foundation, and a length of 365.7 m (1,200 ft).
- The dam is located in Kerala but is operated and maintained by Tamil Nadu.
- The catchment area of the Mullaperiyar Dam itself lies entirely in Kerala and thus not an inter-State river.
- In November 2014, the water level hit 142 feet for first time in 35 years.
- The reservoir again hit the maximum limit of 142 feet in August 2018, following incessant rains in the state of Kerala.
- Indeed, the tendency to store water to almost the full level of reservoirs is becoming a norm among water managers across States.
The dispute: Control and safety of the dam
- Supreme court judgment came in February 2006, has allowed Tamil Nadu to raise the level of the dam to 152 ft (46 m) after strengthening it.
- Responding to it, the Mullaperiyar dam was declared an ‘endangered’ scheduled dam by the Kerala Government under the disputed Kerala Irrigation and Water Conservation (Amendment) Act, 2006.
- For Tamil Nadu, the Mullaperiyar dam and the diverted Periyar waters act as a lifeline for Theni, Madurai, Sivaganga, Dindigul and Ramnad districts.
- Tamil Nadu has insisted on exercising the unfettered colonial rights to control the dam and its waters, based on the 1886 lease agreement.
Rule of Curve issue
- A rule curve or rule level specifies the storage or empty space to be maintained in a reservoir during different times of the year.
- It 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.
- The TN government often blames Kerala for delaying the finalization of the rule curve.