Mullaperiyar Dam

Earlier known as the Periyar Dam as it was basically meant to dam the Periyar river, the present name Mullaperiyar is derived by blending the names of Mullayar River and Periyar River, at the confluence of which the dam is located below. ==Purpose==

The Periyar river which flows westward of Kerala in to the Arabian Sea was diverted eastwards 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 of water than the small Vaigai River could provide. Currently, the water from the Periyar (Thekkady) Lake created by the dam, is diverted through the water shed cutting and a tunnel to Forebay Dam near Kumily (Iraichalpalam). From the Forebay dam, hydel pipelines carry the water to the Periyar Power Station in Lower Periyaru. This is used for power generation (180 MW capacity) in the Periyar Power Station. From the Periyar Power Station, the water is let out into Vairavanar river and then to Suruliyar and from Suruliyar to Vaigai Dam. ==Design==

The Mullaperiyar Dam is a gravity dam made with concrete prepared from limestone and "surkhi" (burnt brick powder), and faced with rubble. Gravity dams use their weight and the force of gravity to support the reservoir and remain stable. The main dam has a maximum height of and length of . Its crest is wide while the base has a width of . It consists of a main dam, spillway on its left and an auxiliary dam (or "baby dam") to the right. Its reservoir can withhold of water, of which is active (live) storage.{{cite book ==History==

Feasibility studies The unique idea of harnessing the westward flowing water of the Periyar river and diverting it to the eastward flowing Vaigai 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 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. 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-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. As of 2013 the matter is pending before a Division Bench of the Supreme Court. The dispute puts into question the power of the federal government of India to make valid orders respecting Indian States, in this case regarding a watershed and dam within one state that is used exclusively in another. Construction In May 1887, construction of the dam began. 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, Dindigul District, Madurai District, Sivaganga District and Ramanathapuram districts of Tamil Nadu, then under British rule as part of Madras Province (Sandes, 1935). ==Protected area==

The Periyar National Park in Thekkady, a Protected area of Kerala, is located around the dam's reservoir, the Periyar lake. 62 different kinds of mammals have been recorded in Periyar, including many threatened ones. Periyar is a highly protected tiger reserve and hosts 35 tigers above two-years of age as of January 2017 in the reserve. Declared an elephant reserve on 2 April 2002, the population of Indian elephants in 2005 was estimated at 1100, Other mammals found here include gaur, bison, sambar (horse deer), barking deer, mouse deer, dholes (Indian wild dogs), mongoose, foxes and leopards. Four species of primates are found at Periyar – the rare lion-tailed macaque, the Nilgiri langur, the common langur, and the bonnet macaque. According to a report by the Kerala Forest Research Institute, the protected area surrounding the dam and reservoir is classified as a biodiversity hot spot. ==Dam safety==

After the 1979 Morvi Dam failure which killed up to 15,000 people, safety concerns of the aging Mullaperiyar dam and alleged leaks and cracks in the structure were raised by the Kerala Government. A study conducted by The Centre for Earth Science Studies (CESS), Thiruvananthapuram, had reported that the structure would not withstand an earthquake above magnitude 6 on the Richter scale. During a 2011 scanning of the Mullaperiyar dam using a remotely operated vehicle by the Central Soil and Materials Research Station on directions from the Empowered Committee of the Supreme Court, the Kerala Government observer opined that "mistakes in the strengthening works carried out by Tamil Nadu" in 1979 damaged the masonry of the dam. Current safety concerns relate to several issues. Since the dam was constructed using stone rubble masonry with lime mortar grouting following prevailing 19th-century construction techniques that have now become archaic, seepage and leaks from the dam have caused concern. Moreover, the dam is situated in a seismically active zone. An earthquake measuring 4.5 on the Richter scale occurred on 7 June 1988 within 20 km of the dam. Subsequently, several tremors have occurred in the area in recent times. These could be reservoir-induced seismicity, requiring further studies according to experts. A 2009 report by IIT Roorkee stated that the dam "was likely to face damage if an earthquake of the magnitude of 6.5 on the Richter scale struck its vicinity when the water level is at 136 feet". ==Justice A.S. Anand Committee (Empowered Committee)==

On 18 February 2010, the Supreme Court decided to constitute a five-member empowered committee consisting three judges and two technical experts to inspect and study all the issues of Mullaperiyar 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. The then late 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, the then Leader of Opposition i.e., the late Chief Minister of Tamil Nadu 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 K. T. Thomas will represent Kerala on the expert panel constituted by Supreme Court. On 8 March 2010, 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. The Supreme Court also criticized the Union Government on its reluctance in funding the empowered committee. The Empowered Committee headed by the former Chief Justice of India A.S. Anand, in its findings concluded that the dam is "structurally, hydrologically safe, and Tamil Nadu can raise the water level from 136 to 142 feet after carrying out repairs." ==Interstate dispute==

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. Supreme court judgment came on 27 February 2006, allowing Tamil Nadu to raise the level of the dam to after strengthening it. Responding to it, Mullaperiyar dam was declared an 'endangered' scheduled dam by the Kerala Government under the disputed Kerala Irrigation and Water Conservation (Amendment) Act, 2006. Tamil Nadu has insisted on raising the water level in the dam to 142 feet, pointing out crop failures. However, the court has clarified Tamil Nadu is not a riparian state. "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." The Kerala Government maintains that this is not true. During the year 1979–80 the gross area cultivated in Periyar command area was . After the lowering of the level to , the gross irrigated area increased and in 1994–95 it reached . 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 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 been challenged by Tamil Nadu 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. In May 2014 the Supreme Court of India declared the Kerala Irrigation and Water Conservation (Amendment) Act of 2006 as unconstitutional and struck down the law passed by the Kerala Assembly on the Mullaperiyar Dam that said that the water level cannot be increased beyond 136 feet. The court has ruled that Tamil Nadu can increase the water level to 142 feet and constituted a permanent Supervisory Committee in order to take care of the affairs relating to maintenance of the Mullaperiyar Dam. ==Supervisory Committee==

In 2014 while passing the final verdict, the Supreme Court constituted a permanent Supervisory Committee to oversee all the aspects of the Mullaperiyar dam. The Supervisory Committee consists of three members headed by member from the Central Water Commission of The Water Resource Ministry who will act as the chairman of the Supervisory Committee and two other members from the respective states. To assist the three member supervisory committee, a five-member sub-supervisory committee was formed comprising two officials from both the respective States and a member from the Central Water Commission acting as the head. ==Proposal for construction of a new dam and other proposals==

In 2014 while passing the final judgement the Supreme Court has laid down criteria for any future construction of new dam downstream and decommissioning of the present Mullaperiyar Dam under the "Way Forward - Towards an amicable solution" or a tunnel solution as suggested by the Empowered Committee (EC). The second tunnel can bring down the water level considerably in the dam and it is as good as decommissioning the dam without hindering supply of water to Tamil Nadu. New dam vs second tunnel The judgement emphasized the suggestion of EC to make a second tunnel at about 50 ft from the bottom so that the large quantity of water, otherwise unused below the current tunnel at 106.5 ft, can be used by Tamil Nadu. It was highlighted that in case the dam develops any distress, this tunnel will help in evacuation of storage faster and better. It was also pointed out that the costs will be meagre compared to building a new dam. ==2021 developments==

The safety of the dam again rose to public attention in 2021 after the flood situation in Kerala in 2018, and the destruction of the Rishiganga hydroelectric project & the Tapovan dam in Uttarakhand following a glacier burst that killed nearly 200 people. A UNU-INWEH report on threats posed by ageing dams across the world stated that the Mullaperiyar dam situated in a seismically active area has major structural flaws and 3.5 million people are at risk if the 100+ years old dam were to fail. Tension rose again when Tamil Nadu opened 10 shutters of the dam after midnight without giving proper warning, causing floods along the banks of the Periyar River. It was the 4th time in a month that Tamil Nadu had opened the shutters of the dam after 10 pm. This resulted in the Chief Minister of Kerala, Pinarayi Vijayan sending a letter to his Tamil Nadu counterpart to open the shutters of the dam only at daytime and with proper warnings. ==In popular culture==

The Malayalam movie L2: Empuraan shows a fictional depiction of the Mullaperiyar Dam, with a villain attempting to sabotage the dam facility by planting bombs. Furthermore, it portrayed that the collapse of the dam would result in a significant part of Kerala being washed away. The film also criticised the 999-year lease deed of the dam, signed before independence, through which Tamil Nadu operates the dam located in Kerala. ==See also==