MULLAPERIYAR DAM - GEOGRAPHY
News: Water level in Mullaperiyar touches 136 ft, first warning issued
What's in the news?
● Tamil
Nadu has issued the first warning with water level in the Mullaperiyar dam
reaching 136 ft on November 9 evening.
● The
upper rule level is 141 ft till November 20, as per the present rule curve for
the dam. The maximum storage level as
per the Supreme Court order is 142 ft.
Mullaperiyar Dam:
● The
Mullaperiyar dam, built 126 years ago, is located in Kerala's Idukki district
at the confluence of the Mullayar and Periyar rivers.
● The
dam has a height of 53.66 meters and a length of 365.85 meters.
● Tamil
Nadu owns, operates, and maintains the dam under a 999-year lease contract signed in 1886 in between Maharaja of
Travancore and the Secretary of State for India for Periyar Irrigation Works.
● Tamil
Nadu maintained it for a number of reasons, including irrigation, drinking
water supply, and hydropower generation.
● It
is a masonry gravity dam built of
concrete and stone, with the weight of the dam pressing it down onto the
foundation.
● In
November 2014, the water level hit 142 feet for the 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.
Rule curve:
● A
dam’s rule curve determines the reservoir’s fluctuating storage levels.
● A
dam’s gate opening schedule is
determined by the rule curve.
● It
is a component of a dam’s “core safety”
mechanism.
● The
level of the rule curve is fixed to avoid emergency dam shutter opening in the
event of a flood-like situation.
● It aids in maintaining a stable water level in the dam during the monsoon season.
Periyar river:
● The
Periyar is the longest river in the
state of Kerala with a length of 244 km.
● It
is also known as ‘Lifeline of Kerala’
as it is one of the few perennial rivers in the state.
● It
originates from Sivagiri hills of Western Ghats and flows through the Periyar
National Park.
● The
main tributaries of Periyar are Muthirapuzha,
Mullayar, Cheruthoni, Perinjankutti.