History of Idukki Arch Dam – The Idea and Construction
Idukki Arch Dam in the southern Indian state of Kerala is the first of its kind in Asia. It is a Double Curvature Arch Dam impounding Periyar River at a narrow gorge between two granite hills in Idukki, Kerala. In a layman’s explanation – a double curvature arch dam is a dam which is curved both horizontally and vertically towards the upstream i.e. towards the source.
Such type of dams are thinner than ‘earth filled’ or ‘masonry’ dams and are also economical as they require less amount of concrete. They are suitable for narrow gorges as the hydrostatic pressure of the water pressing against its curved surface; strengthens its structure.
The dam is constructed and owned by the ‘Kerala State Electricity Board’ and the water stored by the Idukki curved dam as well as two other dams; Cheruthoni- a Concrete Gravity Dam and Kulamavu- a Gravity/Masonry Dam is used by the Hydroelectric Power Station at Moolamattom (780 MW), which is an underground power station located inside a cave. The approximate distance between the Idukki Arch Dam and the Hydro Power Station at Moolamattom is 43 km and the water from the dam to the station is carried by underground pipes.
Legend of Kuravan and Kurathi
There is a small but interesting mythological story told by the locals for centuries about the two hills Kuravan Mala and Kurathi Mala. The legend has it that when Lord Rama and Sita were roaming in the forest during exile; Sita settled to bathe in the spot where the Periyar River was flowing through. The tribal couple Kuarvan (male) and Kurathi (female spouse of Kuravan) accidentally came across the bathing Sita and spellbound by her beauty they were caught staring at her by Lord Rama.
Rama was displeased by their act and cursed the couple to be transformed into rocks (hills Kuravan Mala and Kurathi Mala). However the couple pleaded mercy stating that they cannot even think about a life of separation. Softened by their pleading; Rama told them that they will attain ‘moksha’ or salvation during the Kaliyuga when they will be joined forever.
According to the myth, after the curse they became two hills (Kuravan and Kurathi) and Periyar River started flowing between them and with the construction of the Dam joining the two, the promise which Rama made to Kuravan and Kurathi was fulfilled.
History of Idukki Arch Dam – The Idea and Construction
The idea of an arch dam at the location was first conceived as early as 1919 by an Italian engineer Jacob, who submitted a proposal to the Travancore government in this regard; however, the proposal was rejected.
The idea was once again stirred up during a hunting trip of W.J. John- Mallankara estate superintendent and his friend AC Thomas Edattu. The two were on a hunting trip in the location of the present dam guided by the chief of the local ‘Oorali’ tribe. Impressed by the chief’s narration of the legend of Kuravan and Kurathi hills and the impressive flow of Periyar River through the gorge between the hills; Thomas suggested the suitability of the location for construction of an Arch Dam.
Once again in 1932 W.J. John submitted a report to the Travancore government for the construction of an Arch Dam impounding Periyar river at the gorge between Kuravan and Kurathi hills. This time the report included the technical details of utilizing the dam for the purpose of electricity generation.
Later the issue of the dam was notified to the Travancore government in 1935 by the Travancore Assembly member Shri K.A. Narayana Pillai; unfortunately the government didn’t pay much attention to it, although a technical study was conducted by two Italian engineers Angelo Omedeyo and Clantheyo Masele.
It was only during 1947 that the government of Travancore asked its Chief Electrical Engineer- P. Joseph John, to submit a report on dam’s construction; which was submitted to the government the same year. On the request of the Government of India the Central Water commission conducted a detailed investigation of the project in 1956. Consequently the report was prepared in 1961 and the project was sanctioned by the planning commission in 1963. Initial works of the projected started in 1964 under the guidance of Superintending Engineer E.U. Philipose.
The construction of the dam began around five years later on April 30th1969. Several retired as well as working engineers like C.V. Mathews (Retd. Chief Engineer) were employed to supervise the project. The project was provided long term loan and aid by the Government of Canada and also a Canadian firm of consulting engineers. SNC Lavalin was advising project engineers on Canadian aid. The bid of construction was won by the Hindustan Construction Company (HCC) of Walchand group founded by the Indian Industrialist Walchand Hirachand Doshi.
The storage of water in Idukki reservoir commenced in February 1973. Trial run of the first machine was done on October 4th 1975. Finally, on February 12th 1976 the Power Station was commissioned by the then Prime Minister of India Smt. Indira Gandhi.
