Mullaperiyar–A dam of controversies

Mullaperiyar Dam is a masonry gravity dam over River Periyar, with a height of 155 feet and length 1200 feet and is located 2889 feet above m.s.l. on the High Ranges (Cardamom Hills) of Western Ghats in Thekkadi, Idukki District of Kerala, India. It was constructed in 1895 by the British Government, over the headwaters of the west-flowing Periyar River and its tributary Mullaiyar, to divert water eastwards to Madras Presidency area (the present-day Tamilnadu). The Periyar National Park, Thekkady is located around the Periyar reservoir formed by the backwaters of this dam. The dam is operated by the Government of Tamil Nadu based on a 999-year lease agreement made during erstwhile British colonial rule, between the British Government (Madras Presidency) and the Travancore Maharajah.

The catchment areas and river basin of River Periyar downstream include five Districts of Central Kerala, namely Idukki, Kottayam, Ernakulam, Alappuzha and Trissur with a total population of around 3.5 million. Water diverted eastward flows through a tunnel from the dam, joins River Vaigai in Tamilnadu, and is used for irrigation and power generation in Tamilnadu. The Periyar Power Station in Lower Periyar, Tamilnadu generates hydro-electricity from the diverted waters. The dam has been a bone of contention between the State Governments of Kerala and Tamilnadu, with Tamilnadu demanding raising of water level in the reservoir to increase flow of water to Tamilnadu, and Kerala objecting to this on the grounds of safety of the 116 year old reservoir that is built using lime and surkhi mortar. Earthquakes in the area have further highlighted safety issues and concerns. Various issues are still being adjudicated by the Supreme Court of India.

 

Periyar river originates in the Sivagiri Hills of the Western Ghats in Kerala, flows northwards and at Thekkady joins the west-flowing Mullaiyar, also originating in the Western Ghats in Kerala. The Mullaperiyar dam is constructed at the confluence of both the rivers Periyar and Mullaiyar to create the Periyar reservoir. From Periyar Thekkady reservoir, water is diverted eastwards to Tamilnadu via a tunnel enabling the water to join the Vaigai River. From Periyar Thekkady Reservoir, the Periyar river flows northwestward into the Idukki reservoir formed by the Idukki, Cheruthoni and Kulamavu dams. From Idukki reservoir, Periyar river flows northwestwards and then westward to join the Arabian sea at Munambam near Kodungallur and the Vembanad lake at Kochi.

 

History of the Dam

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. This was without the consent of the Legislative Assembly of KeralaThis agreement expired in 2000. However, Tamil Nadu still 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

 

The first dam was built by the British Corps of Royal Engineers. After the first dam was washed away by floods, a second dam was built in 1895. it is built with stone and Surki ( A mixture of sugar and Calcium oxide).
The construction work on a small dam began in 1850 but was abandoned. This was because of fever among workers and demand for higher wages. In May 1882, the work on the dam resumed and was entrusted to Major John Pennycuick. It's total estimated cost was Rs. 84.71 lakhs. The reservoir was to have a height of 152 feet and a capacity of 10.56 thousand million cubic feet.

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 ofTravancore, 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 Periyar dam is the first Surkhi concrete dam in a “V” shaped gorge in the Western Ghats over the west flowing Periyar river.  This Periyar river is a perennial river which rises from the Sivagiri group of hills in Kerala state and flows through Kerala state and joins the Arabian sea.  Out of its total catchment of 4976 sq.km only 114sq.km at the origin of the river lies in Tamil Nadu.  It is built of concrete in Surkhi motor (brick powder in lime) with a thick masonry facing and is 173m high above foundation rock with a base width of 144.5ft Its length is 200ft at foundation level and 1241 ft at top.  On both sides of the main valley there are smaller depressions and the one on the left side was blocked by a second dam of the same time with 221ft length and 53ft height which is connected with the high ground by means of an earthen dam.  The depression on the right flank is utilized as an escape channel and it was originally cut down to a level 11ft below the crest of the main dam and it functions as an open weir escape for discharge of  flood flows.  But doubts were expressed about the spillway capacity during heavy floods and in 1908 the level of the escape was reduced by 8ft and a regulator was constructed upon it with 10 spans each of 36ft width, fitted with gates of 16ft height.  There is an extremely huge quantity of Dead Storage provided merely to raise the remainder water to the level at which it can be passed through the tunnel into the Eastern side of the river basin watershed.  The level of the sluice through which the water drawn by the Tamil Nadu is 48ft below the crest of the dam which leaves a Dead Storage water depth of 125ft When full, the lake holds 15.661 TMC  of water out of which 9.176 TMC is utilizable as it is lying above the level of the sluice. From the Northern most arm of the reservoir the water is led for about a mile through a deep open cut channel and then through a tunnel of 5700ft length into another open cut channel on Eastern side of Western ghats which leads into the Surulivar rivulet which discharges into Vaigai river.  After irrigating about 1,27,000 acres in the Surulivar river valley the water is picked up at the Perani regulator across the Vaigai river about 80 miles downstream of the tunnel and flows into the Periyar main canal of 35 miles length.   The main canal of 35 miles length is 100ft wide at its head and discharges 2000 cusecs of water.  The rainfall occurs in 4 out of 5days during June to November when the rain is practically continuous.  Sudden floods from 10,000 to 1,20,000 cusecs are constantly experienced during most of the year.  Sometimes 3 inches of rain is recorded in a period of 4 hours ,resulting in heavy floods.  The project sanctioned in 1884 and started in 1887 was completed by 1897.  Where formerly 66,000 acres of land in Tamilnadu was irrigated from scanty and unreliable water sources 1,85,000 acres was provided with unfailing water supply at a cost of Rs.1.048 crores and the project returns about 6% on capital outlay and proved a financial success.

Controversies Regarding The Dam

The controversies concerning the height and the storage levels of the dam has been a bone of contention between the TN and Kerala Governments, and the case had gone up to the highest court. The Supreme Court in 2006 ruled that the dam was safe enough to increase the storage level by six feet from 136 to 142 ft, but in a subsequent ruling asked the two States to settle the differences through discussions in an amicable manner. Strong demands were aired by all the political parties in Tamil Nadu that Kerala must abide by the earlier Supreme Court ruling about increasing the storage level of the dam. The plea of the Kerala government all through was that raising the storage level of this dam would be a major security threat to the lives and property of the people in three heavily populated districts of the State and to the fauna in Periyar National Park due to increased flooding.
The situation reached the stage of road and rail blockades of the routes leading to Kerala from Tamil Nadu. On Feb. 18,  2010 the Supreme Court ordered that a 5-member Committee headed by former Chief Justice, A.S. Anand, be constituted to look into the dispute and prepare a report within 6 months. This Committee was supposed to be formed within a month of the ruling, but this has not yet happened. The Supreme Court has criticized the Union government on its reluctance to fund the empowered Committee and has also refused the Tamil Nadu government’s request to scrap the idea of this committee. The tones of all the political parties in Tamil Nadu are acrimonious and strident, giving a not very congenial atmosphere for an amicable settlement of the issue.

 

Usually the dams are re-constructed after 60 years. The government will get the expense and huge profit from these years. Even though Mullaperiyar dam has reached the double age it still exists as a big danger for entire people in Kerala. 

Actually Mullaperiyar dam was constructed based on the lease agreement in 1886 between Travancore Princely State and British Presidency of Madras which allow to divert water of Mullaperiyar to British Presidency of Madras (Now Tamil Nadu). The agreement was for 999 years. But after independence entire agreement become lapsed. The agreement was resigned in 1970 between Kerala government and Tamilnadu.

In 1979 Kerala government raised questions about the safeness of Mullaperiyar dam after a minor earthquake in Idukki. Also a state agency reported that the Mullaperiyar dam cannot withstand an earthquake with magnitude 6 on Richter scale. After several controversies Tamil Nadu government decided to reduce the storage level to 136 feet. After several repair Tamil Nadu suggested that storage level can be raised to full 152 feet.

 

Tamil Nadu main point which is used in Mullaperiyar controversies is the lack of water in Tamil Nadu. They argued that about 40,000 crores have been lost due to the destruction of crops between 1980 and 2005 which is the period when height of the dam was reduced to 136 feet. By the appeal of Tamil Nadu in 2006, Supreme Court allows Tamil Nadu to increase the storage level to 142 feet. But Kerala counter this by "Dam Safety Act". But the Tamil Nadu approached the Supreme Court and a notice was send to Kerala. Finally Supreme Court asked to settle the disputes between the states but the problems never end.
In the mean time Kerala thought about constructing a new dam and environment clearance was obtained from Ministry of Environment and Forests of Government in 2009 for conducting surveys. The survey was conducted and three spots were reported. Tamil Nadu tackled this by arguing that creation of new dam is a hidden agenda to keep dam with Kerala.

 

Interesting side information to this water dispute is that Tamil Nadu is now embroiled in water disputes with all the three neighbours—Kerala, Karnataka, and Andhra Pradesh, with the Cauvery dispute with Karnataka remaining an ever ticking bomb. This dispute had already led to several large scale riots in the two States. Being a water scarce State with its agriculture crucially dependent on irrigation water, and vast areas being rain shadow ones and therefore drought prone, it is easy enough to understand how and why the water issue is a highly emotional issue in Tamil Nadu. The common man in Tamil Nadu firmly believes that Kerala is a water and electricity surplus State, and when its government objects to increasing the storage level it is  deliberately obstructing the progress of Tamil Nadu and Tamils. Hundreds of thousands of farming families are crucially dependent on the water from this dam; and Kerala’s objections are construed in Tamil Nadu as a deliberate ploy to prevent the development of agriculture here. The veracity of this belief is certainly subject to serious contention. That Tamil Nadu needs more water is indisputable, but how this water can be obtained is the pertinent question.

Why the Dam is Not Safe?

The main thing we have to consider when looking about the safeness of Mullaperiyar dam is its age. The dam's age become 115 in 2011 and is the one of the oldest dam in Kerala. A special fact which must be kept in mind that, no major reconstruction work has been done on the dam in this long 115 years. The next thing is the materials used for constructing the dam. The dam is purely built with stone and Surki where Surki is a mixture of sugar and calcium oxide. Amazing fact is that Mullaperiyar is the only existing dam in India which is made with Surki. All other dams are reconstructed by authorities for the sake of people but Mullaperiyar dam still remains as a danger to all Keralites.
There is no drainage gallery in Mullaperiyar dam. So the pressure due to the water will be high in Mullaperiyar dam. Mullaperiyar dam doesn't contain any construction blocks and it is arranged in a single block. This kind of architecture in Mullaperiyar dam will create wide spread of cracks in dams. Also there are several cracks in the Mullaperiyar dam due to the flowing of Surkey from dam. According to the authorized details 30.4 tones of surkey are losing from Mullaperiyar dam and it is estimated that about 1500 tones of Surkey have been lost from Mullaperiyar dam in 50 years. The leakage of dam was found in the starting stage itself. The first leakage was found in 1922 and then in 1928-35, 1961-65. The leak was temporarily closed by using cement.

No authorized earthquake study has done in Mullaperiyar so far. Recently some earthquakes in Idukki district has caused serious threat to dam. It is predicted that dam is situated in the earthquake region. Any mild earthquake can cause cracks in Mullaperiyar dam and if the crack is present inside the dam possibility of seeing the crack is rare. These cracks will become big in rainy season where the pressure of water will be high and may cause the destruction of dam. The lack of observing instruments adds the danger of Mullaperiyar dam.
Usually "Dam break analysis" is done along with the construction of dam. This is an analysis done for predicting the possible destruction caused by the destruction of dams. The abstract of saving people from flood will be analyzed in this technique. In modern science this technique is done with the help of computer software Geographical Information System (GIS). But unfortunately no such study has never been conducted in the case of Mullaperiyar dam. 

 

Possible disaster caused by the destruction of Mullaperiyar dam

If Mullaperiyar dam get destroyed the world will be witnessing one of the major destruction. Heavy floods will occur in villages such as Vallakadavu, Vandiperiyar, Keerikkara, Mlamala, Chappathu, upputhara, Ayyappan Kovil, Irattiyar. These villages will almost sink in water.

If the destruction occurs in rainy season,  then about 4430 lakh cubic meter of water will flow into the Idukki dam which is situated just 50 Km away from Mullaperiyar dam. Even though the Idukki dam is constructed for accommodating the water of Mullaperiyar, no-one can give promise that what will happen in Idukki dam with the destruction of Mullaperiyar dam. The capacity of Idukki dam is 1996.30 million cubic water. So heavy flow of soil and water into Idukki dam may cause the destruction of Idukki dam and may causes heavy flood in shores of entire Periyar river. The peoples in the districts like Idukki, Kottayam, Ernakulam, Thrissur and Alappuzha will be effected by the destruction of these dams. Also there is a danger of contaminated disease in these region. The biodiversity of Periyar wildlife sanctuary will be effected with the destruction of Mullaperiyar dam. Periyar wildlife sanctuary is a hot spot of many animals and plants. With the flood heavy destruction will be caused to these animal and plants resulting in the destruction of the biodiversity of entire forest.