Mullaperiyar Dam is a masonry gravity dam on the Periyar River. It is located 881 m (2,890 ft) above mean sea level on the Cardamom Hills of the Western Ghats in Thekkady, Idukki District of Kerala, South India. It was constructed between 1887 and 1895 by the British Government to divert water eastwards to Madras Presidency area (the 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 neighboring Tamil Nadu state. The control and safety of the dam and the validity and fairness of the lease agreement have been points of dispute between Kerala and Tamil Nadu states. The dam is an 'endangered' scheduled dam under the Kerala Irrigation and Water Conservation
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 Madras Presidency which was in dire need of a greater supply than the small Vaigai River could give. The dam created the Periyar Thekkady reservoir, from which water was diverted eastwards to via a tunnel to augment the small flow of the Vaigai River. The Vaigai was dammed by the Vaigai Dam to provide a source for irrigating large tracts around Madurai. Initially 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 which generates hydro-electricity from the diverted waters.
Currently, the water from the Periyar (Thekkadi) Lake created by the dam, is diverted through the water shed cutting and a subterranean tunnel to Forebay Dam near Kumili (Errachipalam) in Tamil Nadu. From Forebay dam, hydel pipe lines carry the water to the Periyar Power Station in Lower Periyar, Tamil Nadu. This is used for power generation (175 MW capacity) in the Periyar Power Station. The Lower Periyar Power Sation was constructed in 1956.
From the Periyar Power Station, the water is let out into Vairavanar river and then to Suruliyar and from Suruliyar to Vaigai Dam.
History
The unique idea of harnessing the westward flowing water of the Periyar river and diverting it to the eastward flowing Vagai river was first explored in 1789 by Pradani Muthirulappa Pillai, a minister of the Ramnad king Muthuramalinga Sethupathy, who gave it up as he found it to be expensive. The location of the dam had first been scouted by Captain J. L. Caldwell, Madras Engineers 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.
Lease
On 29 October 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 Periyar Irrigation Works. The lease agreement was signed by Dewan of Travancore V Ram Iyengar and State Secretary of Madras State J C Hannington. This lease was made after 24 years 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 to. The agreement gave 8000 acres of land for the reservoir and another 100 acres to construct the dam. The tax for each acre was 5 per year. The lease provided the British the rights over "all the waters" of the Mullaperiyar and its catchment basin, for an annual rent of 40,000.
In 1947, after Indian Independence, After British India was partitioned in 1947 into India and Pakistan, Travancore and Cochin joined the Union of India and on 1 July 1949 were merged to form Travancore-Cochin. On 1 January 1950 (Republic Day), Travancore-Cochin was recognised as a state. The Madras Presidency was organised to form Madras State in 1947.
On 1 November 1956, the state of Kerala was formed by the States Reorganisation Act merging the Malabar district, Travancore-Cochin , and the taluk of Kasargod, South Kanara. In 1957, elections for the new Kerala Legislative Assembly were held, and a reformist, Communist-led government came to power, under E.M.S. Namboodiripad.The Communist government initiated pioneering land reforms, leading to lowest levels of rural poverty in India .And the Kerala state govt announced that the agreement which was signed between British Raj and Travancore agreement has expired. And Keral Govt said in need to be renewd. 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 30, and for the electricity generated in Lower Camp using Mullaperiyar water, the charge was 12 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 as tax per year for the whole land and 7.5 lakhs per year as surcharge for the total amount of electricity generated. The validity of this agreement is under dispute between the States of Kerala and Tamil Nadu. The matter is currently pending before a Division Bench of the Supreme Court.
Construction
In May 1887, construction of the dam began. As per "The Military Engineer in India" Vol II by Sandes (1935), the dam was constructed from lime stone and surkhi (burnt brick powder and a mixture of sugar and calcium oxide, one of the archaic construction techniques of 19th century) at a cost of 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 concrete (no real evidence or reference for this) 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 84.71 lak.
The construction involved the use of troops from 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. 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. Due to the coffer dam failures, the British stopped funding the project. Officer Pennycuick raised funds by selling his wife's jewelry to continue the work. In Madurai, Major Pennycuick's statue has been installed at the state PWD office and his photographs are found adorning walls in peoples homes and shops. In 2002, his great grandson was honoured in Madurai, a function that was attended by thousands of people.
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". A large amount of manual labour was involved and worker mortality from malaria was 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". 483 people died of diseases during the construction of this dam and were buried on-site in a cemetery just north of the dam.
Interstate dispute
For Tamil Nadu, Mullaperiyar dam and the diverted Periyar waters act as a lifeline for Theni, Madurai, Sivaganga and Ramnad Districts, providing water for irrigation, drinking and also for generation of power in Lower Periyar Power Station. Tamil Nadu has insisted on exercising its unfettered rights to control the dam and its waters, based on the 1866 lease agreement. Kerala has pointed out the unfairness in the 1886 lease agreement and has challenged the validity of this agreement. However safety concerns posed by the 116 year old dam to the safety of the people of Kerala in the event of a dam collapse, have been the focus of disputes from 2009 onward. Kerala's proposal for decommissioning the dam and construction of a new dam, has been challenged by Tamil Nadu.
Tamil Nadu has insisted on raising the water level in the dam to 142 feet, pointing out crop failures. One estimate states that "the crop losses to Tamil Nadu, because of the reduction in the height of the dam, between 1980 and 2005 is a whopping 40,000 crores. In the process the farmers of the erstwhile rain shadow areas in Tamil Nadu who had started a thrice yearly cropping pattern had to go back to the bi-annual cropping."
In 2006, the Supreme Court of India by its decision by a three member division bench, allowed for the storage level to be raised to 142 feet (43 m) pending completion of the proposed strengthening measures, provision of other additional vents and implementation of other suggestions.
However, the Kerala Government promulgated a new "Dam Safety Act" against increasing the storage level of the dam, which has not been objected by the Supreme Court. Tamil Nadu challenged it on various grounds. The Supreme Court issued notice to Kerala to respond, 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. The Supreme Court of India termed the act as not unconstitutional. Meanwhile, the Supreme Court constituted a Constitution bench to hear the case considering its wide ramifications.
Kerala did not object giving water to Tamil Nadu. Their main cause of objection is the dams safety as it is as old as 116 years. Increasing the level would add more pressure to be handled by already leaking dam.Tamil Nadu wants the 2006 order of Supreme court be implemented so as to increase the water level to 142 feet (43 m).
Construction of a new dam
Kerala enacted the Kerala Irrigation and Water Conservation (Amendment) Act, 2006 to ensure safety of all 'endangered' dams in the State, listed in the second schedule to the Act. Section 62A of the Act provides for listing in the schedule, "details of the dams which are endangered on account of their age, degeneration, degradation, structural or other impediments as are specified". The second schedule to the Act lists Mullaperiyar (dam) constructed in 1895 and fixes 136 feet as its maximum water level. The Act empowers Kerala Dam Safety Authority (Authority specified in the Act) to oversee safety of dams in the State and sec 62(e) empowers the Authority to direct the custodian (of a dam) "to suspend the functioning of any dam, to decommission any dam or restrict the functioning of any dam if public safety or threat to human life or property, so require". The Authority can conduct periodical inspection of any dam listed in the schedule.
In pursuance of Kerala's dam safety law declaring Mullaperiyar dam as an endangered dam, 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. On Sept. 9, 2009 stated it had already communicated to the Government of India as well as to the Government of Kerala that there is no need for construction of a new dam by the Kerala Government, as the existing dam after it is strengthened, functions like a new dam.
It was among the most prominent tourist spots in India during the hippy era. It still has a high status among tourists (mostly European) even now the glory of this beach attracting more and more tourists(western). Kovalam is finding a new significance in the light of several Ayurvedic salons, and recuperation and regeneration resorts which provide a slew of Ayurvedic treatments for the tourists. The sands on the beaches in Kovalam are partially black in colour due to the presence of ilmenite and thorazite. There are two main beaches at Kovalam, separated by a high cliff. There is small light house in the Eve's beach. The normal tourist season is from November to March.
The dam is at the foot of the Nelliampathi hills. From here, the road winds up for the next 17 km, with many hairpin turns on the way. Immediately after Pothundy dam, comes the government forest, where one can see massive teak trees. The road is very narrow and requires a skilled driver behind the wheels. On the way, one can see wild animals like monkey, deer and porcupine. The view of the Pothundy dam from the height is a breathtaking sight. 
Kumarakom is an enthrallingly beautiful tourist spot in Kerala. The blue backwaters and the surface of Vembanad Lake reflect the azure sky. The amazing shades of green of the vegetation that include mangroves, coconut palms, and paddy fields cover the verdant countryside. Channels and waterways wind their way through this green paradise.