Idukki Dam

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Idukki Dam
Idukki Dam seen from downstream
Idukki Dam is located in Kerala
Idukki Dam
Idukki Dam is located in India
Idukki Dam
Location of Idukki Dam in Kerala
Location Idukki taluk , Kerala, India
Coordinates 9°50′34″N 76°58′34″E / 9.84278°N 76.97611°E / 9.84278; 76.97611Coordinates: 9°50′34″N 76°58′34″E / 9.84278°N 76.97611°E / 9.84278; 76.97611
Purpose Power generation
Status Operational
Construction began 30 April 1969
Opening date February 1973
Owner(s) Kerala State Electricity Board
Dam and spillways
Type of dam Concrete, double curvature parabolic, thin arch.
Impounds Periyar River
Height 168.91 m (554 ft)
Length 365.85 m (1,200 ft)
Dam volume 450,000 m3 (16,000,000 cu ft)
Spillways Nil
Total capacity 1,996×10^6 m3 (1,618,184 acre⋅ft)
Active capacity 1,459×10^6 m3 (1,182,831 acre⋅ft)
Inactive capacity 536×10^6 m3 (434,542 acre⋅ft)
Catchment area 649.3 km2 (251 sq mi)
Surface area 60 km2 (23 sq mi)
Normal elevation 732.62 m (2,404 ft)
Power Station
Commission date 1975
Turbines 6 x 130 MW Pelton-type
Installed capacity 780 MW

The Idukki Dam is a double curvature arch dam constructed across the Periyar River in a narrow gorge between two granite hills Kuravan and Kuravathi in Kerala, India. At 167.68 metres, it is one of the highest arch dams in Asia. It was constructed and is owned by the Kerala State Electricity Board. It supports a 780 MW hydroelectric power station in Moolamattom, which started generating power on 4 October 1975.[1] Technically, the dam type is a concrete, double curvature parabolic, thin arc dam.[2]

This dam was constructed along with two other dams at Cheruthoni and Kulamavu. Together, the three dams have created an artificial lake that is 60 km² in area. The stored water is used to produce electricity at the Moolamattom Power house, which is located inside nearby rocky caves. The Government of Canada aided in the building of the dam with long term loans and grants.[1]

Idukki Dam Reservoir


The idea of constructing a dam for power generation was first conceived in 1919 in a report submitted by Italian engineer Jacob to the Travencore government. This report was however rejected by the Travencore government. As per history, Shri Chemban Karuvellayan Kolumban, the head of 'Oorali' race during 1922, showed the way to the Malankara Estate Superintendent W.J.John and his friend AC Thomas Edattu, who were on hunting spree in the forest, the spot of present Arch Dam. He told them of the legend of Kuravan and Kurathi Hills. Mr. Thomas was impressed by the sight of water flow between the mountains and it was his idea that has materialized in the form of Idukki Arch Dam. Sri. W.J.John of Malankara Estate submitted a report to the Government of Travancore in 1932 on the possibility of constructing a dam at Idukki for Power Generation.[3]

In 1935, assembly member Shri.K.A.Narayana Pillai brought the Idukki project to the attention of Government of Travancore. Italian engineers Angelo Omedayo and Clantheyo Masele conducted a study in 1937 but things didn't went forward.

In 1947, a preliminary investigation report was prepared and submitted by Sri. P. Joseph John, the then Chief Electrical Engineer to the Government of Travancore. It was during 1956 that the Central Water Commission conducted a detailed investigation based on the Government's request. The project report was prepared in 1961 and the Planning Commission accorded sanction for implementing the scheme in 1963. In 1964, under the leadership of Sri. E.U.Philipose, Superintending Engineer, preliminary works of the project were started.

The construction of this Dam commenced on 30 April 1969 under the guidance of several engineers like Sri. C.V Mathews(Retired Chief Engineer, Electricity Board) . Storage of water in Idukki reservoir commenced in February, 1973. The inauguration of trial run of the first machine was celebrated on 4 October 1975. Commercial operation of the Power Station was Commissioned on 12 February 1976 by the then Hon. Prime Minister Smt. Indira Gandhi. The Government of Canada aided the Project with long term loans and grants. M/s S.N.C.Inc., Canada, a well-known firm of Consulting Engineers were advising and assisting Project Engineers under Canadian aid.


Idukki Dam is 554 feet (168.91 meters) tall, constructed between the two mountains - Kuravanmala (839 meters) and Kuravathimala (925 meters ). Length of the dam on its top is 365.85 meters. It has a width of 7.62 meters in the top and 19.81 meters in the bottom. About 4,64,000 cubic meters of concrete was used in the construction of the dam. This project is situated in Idukki District and its underground power house is located at Moolamattom which is about 43 km from the dam.

Twice in the past, the shutters (of Cheruthoni) had to be opened; during the northeast monsoon (October to December) on both occasions. The first time was in 1981 (when the shutters were repeatedly opened and shut between 29 October and 13 November) and the second time was in 1992 (when they were kept open for 12 days from 12 to 23 October). On both occasions, the water level in the dam touched the brim only when the storage built up during the southwest monsoon (June to September) was augmented by the inflow received immediately afterwards following heavy downpour early in the northeast monsoon.[4]

Kulamavu Dam Reservoir


Power Generation

The Project harnesses a major portion of the power potential of Periyar, the largest river in Kerala, by the creation of a reservoir of 2,000 M.cum (2 Billion Tonnes) capacity, diversion of waters thus impounded through a water conductor system consisting of a power tunnel and two underground pressure shafts to an underground power house situated in Moolamattom. The installed capacity of the Power House is 780MW consisting of 6 Units of Pelton-type turbines with a power generation capacity of 130 MW each. The regulated waters of Periyar falls through a drop of about 669.2 metres (2195 feet) while generating power in the underground power house.


The tail waters flowing to Kudayathurpuzha through tunnel and open channel is diverted for irrigation purposes in the Muvattupuzha Valley.

Tourist destination and attraction

Earlier, there was a blanket ban on public entry in to the dam due to security reasons. Later, it was relaxed opening the dam for public for 10 days during the Onam and the Christmas seasons. The duration has been increased to one month since last year. Cameras and cell phones are not allowed inside the dam area. The entry fee is Rs.25 for adults and Rs.5 for children. The fee for 15-minute boating service for five persons is Rs. 600.[5]

Idukki valley is 121 km away from Kottayam, and is a small hill town surrounded by a spread of beautiful, wooded valleys and meandering streams. Idukki is a well known tourist center in Kerala.

The Idukki Wildlife Sanctuary extends over the Thodupuzha and Udumbanchola taluks of Idukki district, spread over 77 km2 and is about 450 – 748 m above sea level. The Idukki Reservoir formed by three dams - Cheruthoni, Idukki and Kulamavu - extends to 33 km2. One can find Elephants, bisons, sambars, deers, wild dogs, jungle cats, tigers, wild boars etc. and a variety of snakes like cobra, viper, krait and a number of non-poisonous snakes in this sanctuary. The birds of Idukki are Jungle fowl, myna, laughing thrush, black bulbul, peafowl, woodpecker, kingfisher etc.

See also[edit]


  1. ^ a b "Idukki District Hydroelectric projects". Retrieved 2007-03-12. 
  2. ^ "Salient Features - Dam". Retrieved 2007-03-12. 
  3. ^ Idukki
  4. ^ Hindu, The. "Countdown to Idukki dam opening begins". The Hindu. Retrieved 21 September 2013. 
  5. ^ Hindu, The. "Filled to its brim, Idukki dam woos tourists". The Hindu. Retrieved 21 September 2013. 

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