Mullaperiyar Dam is a masonry gravity dam on the Periyar River. It is located 2,889 ft (881 m) above mean sea level on the Cardamom Hills of Western Ghats in Thekkadi, Idukki District of Kerala, India. It was constructed in 1895 by the British Government, to divert water eastwards to Madras Presidency area (the present-day Tamil Nadu). It has a height of 176 ft (54 m) from the foundation and length of 1,200 ft (366 m). The Periyar National Park, Thekkady is located around the dam’s reservoir. The safety of the dam has been a matter of concern and a point of dispute between Kerala and Tamil Nadu States.
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Dam construction
The location of the dam had first been scouted by Captain J. L. Caldwell, Madras Engineers (abbreviated as M.E.) in 1808 to reconnoitre the feasibility of providing water from the Periyar river to Madurai by a tunnel through the mountains. Caldwell discovered that the excavation needed would be in excess of 100 feet in depth and the project was abandoned with the comment in his report as “decidedly chimerical and unworthy of any further regard”.
The first attempt at damming the Periyar with an earthen dam in 1850 was given up due to demands for higher wages by the labour citing unhealthy living conditions. The proposal was resubmitted a number of times and in 1862, Captain J. G. Ryves, M.E., carried out a study and submitted proposals in 1867 for another earthwork dam, 62 feet high. The matter was debated by the Madras Government and the matter further delayed by the terrible famine of 1876-77. Finally, in 1882, the construction of the dam was approved and Major John Pennycuick, M.E., placed in charge to prepare a revised project and estimate which was approved in 1884 by his superiors.
In May 1882, the construction of the dam began. As per “The Military Engineer in India” Vol II by Sandes (1935), the dam was constructed from concrete and masonry at a cost of Rs 104 lakhs, was 173 feet high and 1241 feet in length along the top and enclosed more than 15 thousand million cubic feet of water.Another source states that the dam was constructed of lime and surki (a mixture of sugar and calcium oxide), and gives a figure of 152 feet height of the full water level of the reservoir, with impounding capacity of 10.56 thousand million cubic feet along-with a total estimated cost of Rs. 84.71 lakhs.
The dam created a reservoir in a remote gorge of the Periyar river situated 3,000 feet above the sea in dense and malarial jungle, and from the northerly arm of this manmade waterbody, the water flowed first through a deep cutting for about a mile and then through a tunnel, 5704 feet in length and later through another cutting on the other side of the watershed and into a natural ravine and so onto the Vaigai River which has been partly built up for a length of 86 miles, finally discharging 2000 cusecs of water for the arid rain shadow regions of present-day Theni, Madurai District, Sivaganga District and Ramanathapuram districts of Tamil Nadu, then under British rule as part of Madras Province (Sandes, 1935).
The Periyar project, as it was then known, was widely considered well into the 20th Century as “one of the most extraordinary feats of engineering ever performed by man”. The greatest challenge was the diversion of the river so that lower portions of the great dam could be built. The temporary embankments and coffer-dams used to restrain the river waters were regularly swept away by floods and rains. An extremely large amount of manual labour was involved and the mortality of the workers from malaria was extremely high. It was claimed that had it not been for “the medicinal effects of the native spirit called arrack, the dam might never have been finished”.The construction also involved the use of troops namely, the 1st and 4th battalions of the Madras Pioneers as well as Portuguese carpenters from Cochin who were employed in the construction of the coffer-dams and other structures.
Lease
On 29 October 1886, a lease indenture for 999 years was made between Maharaja of Travancore, Vishakham Thirunal and Secretary of State for India for Periyar irrigation works. The lease agreement was signed by Dewan of Travancore V Ram Iyengar and State Secretary of Madras State (under British rule) J C Hannington. This lease was made after constant pressure on Travancore King by the British for 24 years. The lease indenture inter alia granted full right, power and liberty to construct, make and carry out on the leased land and to use exclusively when constructed, made and carried out all such irrigation works and other works ancillary thereto to Secretary of State for India (now Tamil Nadu). The agreement was to give 8000 acres of land for the reservoir and another 100 acres to construct the dam. And the tax for each acre was 5 RS per year. When India became independent, the lease got expired. After several failed attempts to renew the agreement in 1958, 1960, and 1969, the agreement was renewed in 1970 when C Achutha Menon was Kerala Chief Minister. According to the renewed agreement, the tax per acre was 30 RS, and for the electricity generated in Lower Camp using Mullaperiyar water, the charge was 12 RS per kiloWatt per hour. Tamil Nadu uses the water and the land, and the Tamil Nadu government has been paying to the Kerala government for the past 50 years 2.5 lakhs Rs as tax per year for the whole land and 7.5 lakhs RS per year as surcharge for the total amount of electricity generated.
Although Kerala claims that the agreement was forced on the then princely State of Travancore, presently part of Kerala, the pact was re-validated in 1970 by Kerala and Tamil Nadu. The lease provided the British the rights over “all the waters” of the Mullaperiyar and its catchment basin, for an annual rent of Rs. 40,000.
The National Register for Large Dams lists the Mullaperiyar dam as located in Kerala, but operated by Tamil Nadu
Construction of a new dam
Kerala enacted the Kerala Irrigation and Water Conservation (Amendment) Act, 2006 to ensure safety of all dams in the State including the Mullaperiyar dam. The law empowered Kerala’s Dam Safety Authority to oversee safety of dams in the State with powers to direct Tamil Nadu to suspend or restrict the functioning of the Mullaperiyar dam, to prevent submergence of land beyond the leased land; protect environment, flora and fauna; promote tourism and ensure the safety and security of its inhabitants.
In pursuance of Kerala’s dam safety law, in September 2009, the Ministry of Environment and Forests of Government of India granted environmental clearance to Kerala for conducting survey for new dam downstream. Tamil Nadu approached Supreme Court for a stay order against the clearance; however, the plea was rejected. Consequently, the survey was started in October, 2009.
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