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(ARCHIVE) Vol. XXI No. 23, March 16-31, 2012
... The Mullaperiyar Dam
by A. Mohanakrishnan
Advisor, Water Resources to the Tamil Nadu Government

Mullaperiyar Dam is a masonry gravity dam on the Periyar River, 881 m (2,890 ft) above mean sea level in the Cardamom Hills of the Western Ghats in Thekkady, Idukki District, Kerala. It was constructed between 1887 and 1895 by the British Government to divert water eastwards to a part of the Madras Presidency (a part of present-day Tamil Nadu). It has a height of 53.6 m (176 ft) from the foundation and length of 365.7 m (1,200 ft). The Periyar National Park in Thekkady is located around the dam's reservoir. The dam and the river are owned by and located in Kerala, but the dam is controlled and operated under a period lease by neighbouring Tamil Nadu. The dam and the validity and fairness of the lease agreement have long been points of dispute between Kerala and Tamil Nadu.

Earlier known as the Periyar Dam, as it was basically meant to dam the Periyar River, its present name is Mullaperiyar Dam, derived from a portmanteau of Mullayar River and Periyar River, below the confluence of which the dam is located.

The geography of the Periyar River which flows westward into the Arabian Sea was diverted eastward to flow towards the Bay of Bengal to provide water to the arid rain shadow region of Madurai in the Madras Presidency, which was in dire need of a greater water supply than the small Vaigai River could give. The dam waters were used only for the irrigation of 68,558 ha (169,411 acres). Later, the Periyar Power Station in the lower Periyar, Tamil Nadu, was built to generate hydro-electricity from the diverted waters.

The crest of the dam is 3.6 m (12 ft) wide while the base has a width of 42.2 m (138 ft). It consists of a main dam, a spillway on its left, and an auxiliary dam (or 'baby dam') to the right. Its reservoir can hold 443,230,000 m3 (359,332 acre-ft) of water, of which 299,130,000 m3 (242,509 acre-ft) is active (live) storage.

* * *

The location of the dam had first been scouted by Captain J.L. Caldwell, Royal Engineers (abbreviated as R.E.), in 1808 on a reconnoitring mission to assess the feasibility of providing water from the Periyar River to Madurai by a tunnel through the mountains.

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 which cited unhealthy living conditions. The proposal was resubmitted a number of times and, in 1862, Captain J.G. Ryves, R.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, R.E., was placed in charge to prepare a revised project and estimate. These were approved in 1884 by his superiors.

The credit for the concept, design and construction of the Mullaperiyar Dam should go mainly to two British engineers, Major Ryves, the District Engineer of Madurai District, who gave a practical form in 1862 for diversion of Periyar waters to benefit the drought-prone areas of the then Madurai and Ramanathapuram Districts, and Colonel J. Pennycuick, who not only made a report with detailed estimates for the Mullaperiyar Dam in 1882 but also ventured against all odds in the most inhospitable dense forest, struggling with single-minded devotion for a good cause and completed the structure in 1895.

Just to the west of the Vaigai river basin in Tamil Nadu, on the other side of the Western Ghat ridges, lies the Periyar basin in Kerala State. The River Periyar, as the name implies, is the one which drains the largest catchment among the west-flowing rivers of Kerala State.

The River Periyar rises in the Sivagiri peak of the Western Ghats in the Quilon District, 80 km south of Devikulam, at an elevation of about 2,400 m and traverses through high cliffs and dense forests for about 186 km, where the tributary Mullaiyar joins it on the right at an elevation of about 850m. The river then turns west, cuts through the hills in a deep narrow gorge in sound hard rock that gave an excellent formation that Col. Pennycuick chose to use for constructing the Mullaperiyar gravity masonry dam. The River Periyar runs through 232 km traversing the taluks of Peermedu and Devikulam and parts of Ernakulam District before draining into the well-known Vembanad Lake.

The Madras Government from 1862 entered into correspondence with the erst-while Travancore Government which was in possession of the territory where the dam was to be built. The Travancore Government which originally showed interest in launching the Mullaperiyar dam project as a joint project later pulled out of the joint project. By a letter dated October 24, 1873 to the British Resident, it then offered to accept a sum of Rs.75,000 a year from 1882 as lease rent for the site of the reservoir, which was later surveyed to extend over 8,000 acres, and agreed to grant the entire water stored therein to the Government of Madras.

On October 29, 1886, a lease indenture for 999 years was made between the Maharaja of Travancore, Visakham Thirunal Rama Varma, and the British Secretary of State for India for the Periyar Irrigation Works. The lease agreement, to take retrospective effect from January 1, 1886, was signed by the Dewan of Travancore, V. Ram Iyengar and the State Secretary of Madras State, J.C. Hannington. This lease was agreed on after 24 years of negotiation between the Maharaja and the British. The lease indenture granted full right, power and liberty to the Secretary of State for India "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... The agreement gave 8000 acres of land for the reservoir and another 100 acres for construction of the dam. The tax for each acre was Rs.5 per year when India became independent.

In May 1887, construction of the dam began at a cost of Rs. 104 lakh. It finally began discharging 2000 cusecs of water for the arid rain shadow regions of present-day Tamil Nadu – the Theni, Madurai, Sivaganga, and Ramanatha-puram Districts, then under British rule as part of Madras Province. 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.

Among the construction materials, stone, the principal constituent of the dam, was locally available for quarrying as was the sand in the river. But lime and surki for the mortar, designed as three parts of sand, two of lime and one of surki, had to be transported through dense forests. So were many of the construction equipment and other materials from the temporary camp at Thekkady, 13 km away, on the other side of the Ghat.

Five different methods of conveyance were considered, all expensive and difficult to organise, including a ropeway across the valley. Eventually, whatever was found convenient at the time was adopted.

It should be specifically mentioned that throughout this decade of construction, great effort was taken to ensure the quality of the materials used and the building of the structures through tests, checks and supervision.

As cement had not made its advent in India when the project was designed and executed, lime surki mortar was used, with the lime being burnt to specification in kiln at site and well ground by a battery of bullock-drawn circular mills and the surki ground to the fineness required by crushers. That the dam structure retains water up to 153 ft above the river bed has been seen for more than a century, with seepage well below the limits prescribed, in spite of the fact that no drilling and grouting was done for consolidation and no drainage gallery was formed in the body of the dam, since both these were unknown practices at that period of time.

* * *

The dam is operated by the Government of Tamil Nadu based on a lease agreement entered into in 1886 by the British India Government and the Maharajah of Travancore. Control of the dam and the reservoir by Tamil Nadu, after Independence and after reorganisation of States, has been a matter of dispute between the States of Kerala and Tamil Nadu. The matter is still sub judice and is currently pending before a Division Bench of the Supreme Court.

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 increased to Rs. 30, and for the electricity generated in Lower Camp using Mullaperiyar water the charge was Rs. 12 per kilowatt per hour. Tamil Nadu uses the water and the land and the Tamil Nadu Government has been paying the Kerala Government for the past 50 years Rs. 2.5 lakh as tax every year for the whole land and Rs. 7.5 lakh as annual surcharge for the total amount of electricity generated.

Under one supplementary agreement signed after Independence by the Government of Madras with the Government of Kerala as successors in interest to the original lease deed of 1886, the annual lease rent was enhanced and the fishing rights in the Periyar Lake were relinquished in favour of the Government of Kerala. By another agreement, which came into effect from November 13, 1954, the Government of Madras would generate hydro power and pay the Government of Kerala for the electrical energy generated at Rs.12 per KW (Kilowatt) year up to 350 million units and at Rs.18 per KW year beyond 350 million units. Thus the Mullaperiyar project has been beneficial to both Tamil Nadu and Kerala.

In 1970, the Kerala and Tamil Nadu Governments signed a formal agreement to renew the 1886 treaty almost completely. The Idukki Hydroelectric project, located 30 km downstream, was completed in 1976 by the Kerala Government. After Independence the areas downstream of the Mullaperiyar became heavily inhabited, as Kerala has a very high population density.

In 1979, safety concerns were raised by the Kerala Government. The then Tamil Nadu Government lowered the storage level to the current 136 feet (from 142.2 feet) at the request of the Kerala Government to carry out safety repairs.

* * *

Tamil Nadu is at present the custodian of the dam and its surrounding areas. In 2006, the Supreme Court of India, by its decision by a single-judge bench, allowed the storage level to be raised to 142 feet (43m). However, the Kerala Government promulgated a new 'Dam Safety Act' against increasing the storage level of the dam, which has not been objected to by the Supreme Court. Tamil Nadu challenged it on various grounds. The Supreme Court issued notice to Kerala to respond; it, however, did not stay the operation of the Act even as an interim measure. The Court then advised the States to settle the matter amicably, and adjourned hearing in order to enable them to do so. Meanwhile, the Supreme Court constituted a Constitution bench to hear the case considering its wide ramifications.

Kerala's stance: Kerala does not object to giving water to Tamil Nadu. Its main cause of objection is the dam's safety, as it is 110 years old.

Tamil Nadu's stance: The State wants that the 2006 order of Supreme Court be implemented, so as to increase the water level to 142 feet (43 m).

Every citizen of India can justifiably take pride in possessing a rare structure in Mullaperiyar Dam, the very first created in the country, perhaps in the world, for trans-basin diversion of water for beneficial use. It was built towards the end of the 19th Century and still continues to serve with its benefits undiminished, through continuous surveillance, maintenance and management by the Tamil Nadu Government.

As one closely associated with this dam and the strengthening measures undertaken, I am pained to see the controversies being raised on its safety, in spite of the opinion of several experts who have inspected the dam and the Supreme Court having accepted the opinion of these experts. – (Courtesy: TCC Digest).

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In this issue

Further Metrorail threats to heritage buildings
Will the Cell-to-be be better than the Committee?
Pennycuick's marvel...
... the Mullaperiyar Dam
The class of '55 meets
San Thomé's 'Father' 'Mack'
Why renovate a building that should not be where it is?

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