Mullaperiyar Dam
Mullaperiyar Dam is constructed over the headwaters of the Periyar River in Kerala, India. The Periyar National Park, Thekkady is located around the Periyar reservoir formed by the backwaters of this dam. It is operated by the Government of Tamil Nadu according to a 999-year lease agreement made during erstwhile British colonial rule.

The name is derived from a portmanteau of Mullaiyar and Periyar. As the dam is located after the confluence of the Mullayar and Periyar Rivers, the river and hence the dam came to be called Mullaperiyar.

Periyar river is a west-flowing river of Kerala State. The river flows its full course entirely through Kerala, and derives its water almost exclusively from catchment area ( Drainage basin) inside the State. The dam stops the west flowing river to form a reservoir, which is also exclusively located in Kerala. From the reservoir, Tamil Nadu collects water to the eastern side of Western Ghats via a tunnel. On 29 October 1886 a lease indenture for 999 years was made between Maharaja of Travancore and Secretary of State for India for Periyar irrigation works. 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). By another agreement in 1970, Tamil Nadu was also permitted to generate power. A first dam was built by the British Corps of Royal Engineers. After the first dam was washed away by floods, a second stonework dam was built in 1895. The dam's purpose was to divert the waters of the west-flowing Periyar River eastward, taking the water from the reservoir through a tunnel cut across the watershed and Western Ghats to the arid rain shadow regions of Theni, Madurai District, Sivaganga District and Ramanathapuram districts of Tamil Nadu. Although Kerala claims that the agreement was forced on the then princely State of Travancore, presently part of Kerala, the pact was revalidated 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 government of Tamil Nadu has proposed an increase in the storage level of the dam from the currently maintained 136 feet (41 m) to 142 feet (43 m). The Kerala government has opposed this move, citing safety concerns for the more than hundred year old bridge and especially for the thickly populated districts downstream. A 10-million-dollar 3D Hollywood movie inspired by these controversies, titled Dam 999 , is scheduled for release in 2011.

Historical background of the dispute
A lease deed was signed between the Travancore Princely State and British Presidency of Madras in 1886 which gave the British the right to divert "all the waters" of the Mullaperiyar and its catchment to British territory (the Madras Presidency, now Tamil Nadu) for 999 years. After Independence, both the entities became non-existent. Further, according to Indian Independence Act 1947, all the treaties between British Government and Indian Princeley States have lapsed. Moreover, Article 131 of the Constitution of India denies Supreme Court of jurisdiction on pre-constitutional agreements. Kerala argued that the agreement is not an equal one, but imposed on the local King by the mightly British Empire. After independence, even in the absence of any treaties, Tamil Nadu continued to use the water from Periyar for extending irrigation facilities, and later for power generation on the basis of informal agreements between the governments of the two states. 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, is still the major resource (about 30%) for irrigation and electricity needs of Kerala. After Independence the areas downstream of the Mullaperiyar become heavily inhabited, as Kerala has a very high population density. In 1979, safety concerns were raised by Kerala Government after a minor earthquake, after which a few leaks were detected in the Mullaperiyar dam. A state agency had reported that the structure would not withstand an earthquake above magnitude 6 on the Richter scale. 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, after which it was suggested that the storage level could be raised to the full reservoir level of 152 feet (46 m). Security concerns regarding the downstream inhabitants prompted Kerala to backtrack on the 1970 Agreement in 2000. Another argument put forward by Kerala on the basis of a report on a study conducted state agencies suggested that the loss of habitat to the fauna of Periyar National Park would occur due to flooding after the increase in the storage level. IIT Delhi conducted a study which stated that the dam safety would be affected even at a level of 136 ft (41 m). IIT Roorkee conducted structural stability study on the Reservoir had found that the structure would not be safe in the event of an earthquake. Meanwhile, the Tamil Nadu government had increased its withdrawal from the reservoir, with additional facilities to cater to the increased demand from newly irrigated areas. One article estimates that "the crop losses to Tamil Nadu, because of the reduction in the height of the dam, between 1980 and 2005 is a whopping Rs. 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." However, the Kerala Government maintains that this is not true. During the year 1979-80 the gross area cultivated in Periyar command area was 171,307 acres (693.25 km 2). After the lowering of the level to 136 ft (41 m), the gross irrigated area increased and in 1994-95 it reached 229,718 acres (929.64 km 2). An article written in 2000 in Frontline stated: "For every argument raised by Tamil Nadu in support of its claims, there is counter-argument in Kerala that appears equally plausible. Yet, each time the controversy gets embroiled in extraneous issues, two things stand out: One is Kerala's refusal to acknowledge the genuine need of the farmers in the otherwise drought-prone regions of Tamil Nadu for the waters of the Mullaperiyar; the other is Tamil Nadu's refusal to see that it cannot rely on or continue to expect more and more from the resources of another State to satisfy its own requirements to the detriment of the other State. A solution perhaps lies in acknowledging the two truths, but neither government can afford the political repercussions of such a confession".

Current status
Tamil Nadu is the custodian of the dam and its surrounding areas. In 2006, the Supreme Court of India has allowed for the storage level to be raised to 142 feet (43 m). 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 it as not unconstitutional. Meanwhile, the Supreme Court constituted a Constitution bench to hear the case considering its wide ramifications. The case involves pre-constitutional agreement between two entities which does not exist now. Kerala's Stance: Kerala did not object giving water to Tamil Nadu. Their main cause of objection is the dams safety as it is as old as 110 years. Increasing the level would add more pressure to be handled by already leaking dam. No masonry dam may survive for 999 years so a new dam may replace the existing one in near future. Tamil Nadu's Stance: The State want that the 2006 order of Supreme court be implemented so as to increase the water level to 142 feet (43 m). 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. The survey team looked at three spots and the final report is expected to be ready by March 2010 for submission to the government. The arguments of Kerala and Tamil Nadu are continuing in the Constitution bench of Supreme Court. Adv. Harish Salve appeared for Kerala and Adv. Parasaran appeared for Tamil Nadu in Supreme Court. Kerala argued that if Mullaperiyar is an interstate river, the Supreme Court has no jurisdiction to intervene in the issue and that it must be dealt with by an independent tribunal. It also argued that if Mullaperiyar is an intrastate river, then the Dam Safety Authority of Kerala is constitutional, and that the Supreme Court has no jurisdiction to intervene in a pre-constitutional agreement. Thus, the water provision is now done under the 1970 review agreement between the States. According to this agreement, only the dam area is leased to Tamil Nadu, and water is not leased. As Kerala does not gain anything from the project inside its territary, it is free to revisit/cancel the 1970 agreement. Kerala also argues that if the water level is increased to 142 feets, wide forest areas that are inhabited by conserved flora and fauna will be inundated. Moreover, as Tamil Nadu controls only the dam, Kerala has no legal restrictions for diverting water to Idukki reservoir through another route, thereby preventing water logging inside Mullaperiyar reservoir. When the Supreme Court sought to know whether a contract could be unilaterally terminated, Mr. Salve said the Legislature had the competence to put an end to the contract, which was not in Kerala’s interest. By legislation, a contract could be varied, altered or annulled. Tamil Nadu argued that the Supreme Court need to look only in to the issue of non-implementation of Supreme Court Order to increase water level of dam by Kerala. Tamil Nadu also asserted that Mullaperiyar is not an interstate river, and thus, there is no need for forming a tribunal. The Tamil Nadu counsel argued that Kerala has an ulterior motive to make a new dam and keep it under its control. Tamil Nadu fears that the water supply will be restricted if Kerala builds a new dam and controls it. However, political controversies arose in Tamil Nadu, as Marumalarchi Dravida Munnetra Kazhagam (MDMK) party and BJP accused the Tamil Nadu counsel is against the interests of Tamil Nadu and demanded the state government to remove him. Vaiko, General Secretary, MDMK, has called for a road blockade on May 28 to stop transport of foodgrains, vegetables and milk to Kerala to protest its proposal to construct a new dam in place of the Mullaperiyar dam. Meanwhile, Kerala proposed that a mechanism may be thought about to supply water to Tamil Nadu similar to the one employed for its supply of drinking water to Coimbatore under the Siruvani water supply scheme. On 18 February 2010, the Supreme Court decided to constitute a five-member empowered committee to study all the issues of Mullaiperiyar Dam and seek a report from it within six months. The Bench in its draft order said Tamil Nadu and Kerala would have the option to nominate a member each, who could be either a retired judge or a technical expert. The five-member committee will be headed by former Chief Justice of India A. S. Anand to go into all issues relating to the dam's safety and the storage level. However, the ruling party of Tamil Nadu, DMK, passed a resolution that it not only oppose the apex court's decision to form the five-member committee, but also said that the state government will not nominate any member to it. Tamil Nadu Chief Minister M. Karunanidhi said that immediately after the Supreme Court announced its decision to set up a committee, he had written to Congress president asking the Centre to mediate between Kerala and Tamil Nadu on Mullaperiyar issue. However, Leader of Opposition J. Jayalalithaa objected to the TN Government move. She said that this would give advantage to Kerala in the issue. Meanwhile, Kerala Water Resources Minister N. K. Premachandran told the state Assembly that the State should have the right of construction, ownership, operation and maintenance of the new dam, while giving water to Tamil Nadu on the basis of a clear cut agreement. He also informed the media that Former Supreme Court Judge Mr. K. T. Thomas will represent Kerala on the expert panel constituted by Supreme Court. On 8 March 2010, in a fresh twist to the Mullaperiyar Dam row, Tamil Nadu told the Supreme Court that it was not interested in adjudicating the dispute with Kerala before the special “empowered” committee appointed by the apex court for settling the inter-State issue. However, Supreme Court refused to accept Tamil Nadu's request to scrap the decision to form the empowered committee. SC also criticized the Union Government on its reluctance in funding the empowered committee.