"Kolaveri" Song : What a Similarity?

Some Guyz have changed the lyrics......

But This seems Matching to the Current Situation.

Mullaperiyar Dam Issue : A Documentary By C-Dit

A documentary by C-Dit on the issue of Mullaperiyar Dam.
A "must see" for keralites and tamilians.

Life Or Agriculture??

Look At this Agriculture or 3 million Lifes......
Which is Important?????

Mullaperiyar dam: An unimaginable disaster waiting to happen

There has been no substantial action taken in all these years by anyone to avoid this catastrophe.

The political parties in Tamil Nadu are no way ready to budge to any suggestions.

I would like everyone in this country to come forward and demand action as Indians, without the stamp of ethnicity or states attached.

We cannot let this disaster happen.

Mullaperiyar dam: An unimaginable disaster waiting to happen

The big question is: Are the lives of 3.5 million Indians who are living today in anxiety and fear of a possible wipe out important to this country?

A civilization is under the threat of a wipe-out.

Whenever a terror attack or security breach happens in our country, we point fingers at our neighbouring country. But here is a problem that can take the lives of so many innocent Indians, which can be stopped.

And what exactly is our political leadership in this country doing? Nothing.

Mullaperiyar dam: An unimaginable disaster waiting to happen

In response to this the Kerala government has promised to deliver the same amount of water to Tamil Nadu without fail. Here arises the concern of people living in the downstream of this river.

If the Mullaperiyar dam collapses, three dams downstream -- Idukki, Cheruthoni and Kolamavu won't be able to withhold the incoming water (around 15 TMC) which in turn will break these dams, resulting in a catastrophe that will put at risk the lives of 3.5 million people.

A dam which has surpassed its lifespan by more than 66 years poses a threat to the lives of 3.5 million people living in five districts of Kerala.

Mullaperiyar dam: An unimaginable disaster waiting to happen

Experts from IIT Delhi & Roorkee had mentioned that the structure will not withstand an earthquake and is under serious threat. After all these reminders and 32 years of legal battle, both parties have not reached a consensus on this issue.

Even after the Kerala government's promise to give water and construct a new dam undertaking all the expenses, subsequent Tamil Nadu governments have turned a blind eye towards any suggestions or negotiations by Kerala.

The reasons raised by Tamil Nadu are water scarcity in five districts of Tamil Nadu which will lead to drought in the region, a valid reason.

Mullaperiyar dam: An unimaginable disaster waiting to happen

Now getting into the controversial part, the catchment areas and river basin downstream includes five major districts of central Kerala -- Idukki, Ernakulum, Kottayam, Alapuzha and Trissur -- which has a total population of 3.5 million people.

In 1979, there were few minor earthquakes experienced in the regions surrounding the dam following which safety concerns were raised over the dam. Since then, both states Kerala and Tamil Nadu have been at loggerheads with each other on the issue.

A state agency had reported that the dam will not withstand an earthquake above magnitude 6 on the Richter scale.

Mullaperiyar dam: An unimaginable disaster waiting to happen

If an earthquake causes the dam to collapse, it can threaten the lives of 3.5 million people downstream. The issue needs to be looked at as a national problem, not as a dispute between two states, says Dipu Santh

India is said to be a country that upholds the slogan "unity in diversity". We proudly state this to everyone around the world, but there is a question that we have to ask ourselves -- is it true or is it just a statement we put forward to hide our failings?

There's a small example I would like to put forward, the present Mullaperiyar dam crisis which should by all means seen as a national issue rather than an issue between two states.

If we dig deep and go into the history, the Mullaperiyar Dam is a masonry gravity dam built over the river Periyar in 1895 during the British colonial rule with a predicted life span of 50 years to divert water eastwards towards the Madras presidency area (present day Tamil Nadu).

The diverted water from this dam is used for irrigation in Sivaganga, Theni, Madurai and Ramanathapuram districts. The Periyar power station in Tamil Nadu produces hydro-electric power from these waters and distributes that electricity in Tamil Nadu.

Mullapperiyar: Issues of Dam Safety

The Mullapperiyar (Mulla Periyar) dam is one of the oldest dams in service in the World. We are talking of safety of the 105-year-old dam when the average life span of well designed and well built dams is generally considered to be about 50 to 60 years by International experts.

The safety issues relating to Mullapperiyar are heavily interlinked with the safety of the dams of the Idukki project downstream. The level of risk associated with a dam is a function of probability as well as consequences of dam failure.* The fact that the failure of the Mullapperiyar dam could lead to failure of the Idukki dam increases the magnitude of the risk associated with the continued use of the Mullapperiyar dam.

Given the size of the Idukki, the extent of the devastation that could result from failure of Idukki dam is unimaginable. Idukki's reservoir capacity is about 74400 million cubic feet of water with a weight of more than 2100 million tonnes. The expert committee set up by the State Government to study the Mullapperiyar issues has stated that failure of Idukki dams would lead to inundation of more than three districts of Kerala. This itself presents a frightening picture. The problem is compounded by the fact that hardly any up-to-date early warnings systems, emergency action plans including an evacuation plan exists in the case of both Idukki and Mullapperiyar. Evacuation of people in the event of a dam break from three highly populated districts is practically impossible. Moreover, no dependable dam break inundation study is available to determine the zones to be evacuated.

The probability of a dam failure depends on many factors such as spillway capacity, seismic resistance, nature of foundation, quality of design and construction, monitoring and maintenance and a host of human factors.* Idukki has some weak points in almost all these respects, which I shall discuss later in this paper.

In the case of Mullapperiyar the main risk factor arises from its age itself. As I pointed out earlier, not many dams of this age are in service in the World now. It is a dam built using old technology and naturally was not based on modern parameters for design of dams. Much of the binding material (lime) have leached out over the years. Though the Tamil Nadu Government has grouted the dam with concrete, the expert committee has concluded that this was neither sufficient nor highly efficient in making up for the loss of lime from the body of the dam. There is the possibility that hollow areas would remain inside the dam whatever be the efforts taken in this regard.

Apart from maintenance, monitoring is an important aspect of keeping a dam safe. The Central Water Commission had suggested installation of a definite pattern of instrumentation at Mullapperiyar to monitor the condition of the dam. Though Tamil Nadu did install some instruments, no measurements had been made available to Kerala. Though the Kerala Government suggested joint monitoring, Tamil Nadu has not agreed to this. In fact, Tamil Nadu engineers have told the technical committee of Kerala that it had not been successful in implementing the necessary instrumentation of the dam. There is apparently no instrumentation in the old portion of the dam. In the backing concrete portion, built as part of the strengthening works, uplift pressure cells, strain metres, joint metres and thermometres have been provided. These were said to have been installed in 1984. However, Tamil Nadu has either not done systematic monitoring of the dam so far or is hiding the data from Kerala. An old dam left without any monitoring itself is a serious matter. Moreover, no instrumentation like piezometres, inclinometres, extensometres and gauging weirs are in place to monitor the foundation.

There is monitoring failures in the case of Idukki dam also. Some of the instruments embedded in the dam were either not working or giving unreliable readings for several years. The Kerala State Electricity Board (KSEB) defaulted on taking regular readings and publishing the data. There is also no indication of sufficient preparedness from the part of the Board for emergency measures such as the opening of the spillways. According to the expert committee, the spillways at Idukki do not have the capacity to handle even the probable maximum flood (PMF) discharge from Mullapperiyar not to speak of a breach of the Mullapperiyar dam. The PMF of Mullapperiyar basin is 6003 cumecs while the maximum spillway and outlet capacity provided at Idukki reservoir is only 5100 cumecs. This mean that a big flood in the Mullapperiyar basin itself can endanger the Idukki dams if they are at or near full reservoir levels. All these should raise concerns even if the Mullapperiyar dam is strong enough.

There is a notion that we got the best of design and technology from Canada for the Idukki project. This is not entirely correct. We went for Canadian assistance mainly because we wanted funding. One of the conditions for assistance was that we would accept technical consultancy and equipment from Canada. Our own proposal for Idukki was to have concrete gravity dams for which our engineers had considerable expertise. The major modifications suggested by the Canadians to our plans were the arch dam at Idukki and underground power tunnel and the underground powerhouse at Moolamattom. The reason for preferring an underground tunnel and powerhouse was the occasional land slips in the district, which could damage pipelines, and saving of steel needed for the over the ground intake structures. The Canadians had considerable expertise in building tunnels.

However, the proposal for arch dam had its pluses and minuses. It reduced costs, but had some inherent problems. Canada had only built its multiple arch dam, Manic-5, at that time. Manic-5 subsequently became a heavy burden on Hydro Quebec which operates the project. The dam developed bulging cracks and problems with the foundation requiring costly maintenance. It is notable that two of the World's biggest dam disasters that occurred before Idukki was built-- Vaiont in Italy in 1963 and Malpaseet in France in 1959, involved arch dams. (In the case of Vaiont, it was a landslide and not the weakness of the arch dam that caused the accident. But it is to be remembered that Idukki is also prone to land slips). Two arch dams, El Atazar in Spain and Kolnbrein in Austria, which were completed around the same period as Idukki, are facing problems, mainly relating to their foundations, now. The repair cost of Kolnbrein is put at 190 million dollars.

To put the situation in the right perspective, it must be noted here that one of the oldest serving dams is the 75-miles arch dam of Australia constructed in 1880. However, such long serving dams are exceptions. There is a limit to the number of years one can keep dams in service through maintenance and strengthening measures. One day, it has to be rebuilt, or the dam will give way. Visionary leaders should anticipate this and act accordingly, though that may be difficult course of action for a popular Government in Tamil Nadu under the present circumstances. The problem with Mullapperiyar is that there is no alternate site for construction of a new dam (unless Tamil Nadu/Kerala is prepared to construct a wider dam downstream at a high cost). So, disruption of water supply is bound to occur if the existing dam is demolished and reconstructed. The leaders should prepare the people to go without water for irrigation for some years, if no other alternatives could be found. Kerala cannot be giving water to Tamil Nadu at grave risk to its own population.

Note: Mullapperiyar dam, located near Kumily in Idukki district of Kerala State in India, is 438.91 metres long and 48 metres high. The front and rear faces are of uncoursed rubble masonry in lime mortar. Concrete with sandstone and lime surkhi mortar forms the core. It was built for a gross storage of 443.23 M Cum. (15.6 TMCft). It is on the Mullapperiyar, one of the tributaries of Periyar (river), and the reservoir formed by it is often referred to as the Periyar reservoir.

The dam was constructed on the basis of a lease deed between the erstwhile Travancore State and Madras Governments (under British rule) in 1886. Now, there is a dispute between the Kerala and Tamil Nadu State Governments, formed after India became an independent country, over raising of the reservoir level at Mullapperiyar. The maximum water level at the reservoir had been lowered to 136 feet about 20 years ago, on the advice of the Central Water Commission, as the dam developed leaks. The Tamil Nadu Government demands that it should be raised to the original 152 feet as the State had strengthened the dam.

Idukki dams

The expert committee has reported that the overflowing loose soil and soil dumped on the river sides down stream would silt the Idukki reservoir down the river. However, it is nobody’s case that such siltation would seriously threaten Idukki either from the safety point of view or reservoir capacity. The real threat will arise, if the Mullapperiyar dam gives way at the peak of a heavy monsoon. Though Idukki may have the capacity to hold the entire storage at Mullapperiyar, a dam failure during monsoon would present a different picture. The waters would bring down much soil and floating debris which can clog spillways and exert considerable stress on the dams downstream. And Idukki is not the safest of dams.

I discuss Idukki dams in more detail here because condition of the Mullapperiyar dam has a direct bearing on the safety of the dams of the Idukki Project. The level of risk arising from a dam is a function of probability of the dam failure and its consequences. Taken individually, the probability of a dam failure is very high in case of Mullapperiyar and low in case of Idukki. However, the consequences are relatively low in case of Mullapperiyar and very high in case of Idukki. Taken together, the risk level is on the high side both in terms of probability and consequences.

Many have come to think that an arch dam is safer than a concrete gravity dam. This is not true. A gravity dam, as the name implies, holds the water because of its sheer weight. On the other hand, the arch dam holds the water because of its design features. Hence, any damage to the structure of dam is more serious in the case of an arch dam. For the same reason an arch dam requires better monitoring.

Mr. Phong Nguyen, heading the Dam Safety and Maintenance wing of Hydro Quebec2, Canada, told me in an interview that in case of arch dams, the foundations come under great stress. This was because of the to and fro movement of the arch when water fills and empties the reservoir. The arch can withstand this movement and pressure eminently. But that is not the case with the foundation where the arch ends. The foundation develops problems because of the stress resulting from this movement.
He noted that he Manic-5 multiple arch dam3 in Quebec is facing serious problems such as bulging cracks in the dam. Hydro Quebec was spending two to three million dollars a year to monitor the dam. It had also spent millions of dollars for grouting and other repair work. Arch dams, he said, were very difficult to monitor and very expensive to repair.

Incidentally, about 87 per cent of dam failures involving concrete dams are reported to have occurred because of foundation failure. In the case of arch dams, the risk of a foundation failure is on the higher side as indicated by Mr. Nguyen.

The Idukki arch dam, at the time of construction, was equipped to monitor even the slightest movement of the dam body and changes in stress. But almost all of the 16 systems which were set up for this purpose are now either malfunctioning or inoperative. The remaining systems are being used sparingly to monitor the dam. Consequently, no data is available after 1990 on the condition of the dam from a safety point of view. This is a serious situation.

I am not detailing the possible consequences of failure of either Mullapperiyar or Idukki to avoid a scare. But it is telling commentary on the Kerala State Electricity Board (KSEB) that it is not properly monitoring the biggest dam in the State on which much of the State’s prosperity and lives of thousands of people living downstream depends. I am also refraining from talking about emergency action plans as it is pointless to speak about such costly plans when the KSEB is not caring about even monitoring of the dam’s condition. I conclude quoting Nguyen:

“Risks increase in the absence of proper maintenance and surveillance.”

Mullapperiyar

The Mullapperiyar dam is more than 100 years old whereas the useful life of a well-designed and well-built dam is generally considered to be about 50 to 60 years. Thus the dam has already exceeded its normal lifetime by 40 to 50 years. So, the concern about its safety is not misplaced. All structures deteriorate over time and become vulnerable to breakage. So has Mullapperiyar.

Hence, it is imperative that measures are taken to replace the dam. In 1979, Kerala, Tamil Nadu and the Central Water Commission came to an agreement that the maximum reservoir level should be kept low at 136 feet and additional spillways should be constructed to avoid the risk of water level rising in the reservoir. It is notable that Tamil Nadu has not completed the construction of spillways even after 17 years. The spillway capacity is very important from the point of dam safety for as many as 50 per cent of dam failures in the World1 had resulted from inadequate capacity of the spillways. Tamil Nadu not only neglected this aspect, but also took certain measures that further jeopardised the dam’s safety. (I am not forgetting that it took some measures to strengthen the foundation of the dam.). It allowed excavated materials to be dumped upstream of the spillways, that too to the level of the spillways.

The expert committee appointed by the Government has reported that the loose earth dumped on the upstream side of the spillway crust would flow over the crust and ogee and might damage the concrete surface. This report was made some time ago. Now plants have started growing over the dumped material. While this may reduce the amount of loose earth that may overflow, it creates the additional risk of debris getting trapped on them and finally blocking the spillway at least partially. In any case, the presence of the dump above the spillway is bound to affect spillway efficiency, which would be crucial in case of a heavy monsoon. If the spillways, including the additional ones proposed, are not fully functional, that would increase the risk to the dam.

DAM SAFETY: MULLAPPERIYAR AND ITS IMPLICATIONS

Paper presented at the workshop on 'Kerala and Inter-State River Water Agreements' jointly organised by the Indian Society of Interdisciplinary Studies and the Press Club, Trivandrum on March 23, 1997 at the Press Club Hall in Trivandrum, Kerala, India.

The technical aspects of dam safety is a subject that should be handled by experts. This paper attempts only an overview of the subject and interpretation of the information available on the safety aspects of Mullapperiyar, Idukki, Kulamavu and Cheruthoni dams, the latter three forming the Idukki reservoir of the Idukki Project in Kerala (India). Some of the material I am discussing here was collected during the Comparative Study of Hydroelectric Projects in Canada and India undertaken by me on a media fellowship from the Shastri Indo-Canadian Institute.

Before going into the specifics of the situation at Mullapperiyar, let us examine some of the factors associated with dam safety.
Dam safety depends on five factors:

1. Complete investigations;
2. Adequate design;
3. Quality construction;
4. Appropriate operation, maintenance and supervision;
5. Adequate alarm mechanism and well-adapted emergency action plans.

While the first three factors are taken care of in the design and construction stages of the project, the last two are taken care of in the operation phase.*

1. The probability of failure (or vulnerability) of a dam depends on many factors:
2. Spillway capacity;
3. Seismic resistance;
4. Nature of the foundations (a dam founded on bed rock is less vulnerable);
5. Quality of design (Competence of the design engineers, verification methods);
6. Quality of Construction (Competence of the contractor and the supervision);
7. Monitoring;
8. Maintenance;
9. Human factors (Social conflict, terrorism, war etc.)

The long term safety of a dam is primarily a function of degradation of its materials. In case of concrete dams, degradation can result from swelling on account of alkali reactions in the aggregates, disintegration of surfaces on account of weather, leaching in construction joints on account of poor preparation during construction, leaching of grout injected into the foundation and excessive deformation of the foundation and degradation of an entire concrete poul on account of the variable quality of mixes used.

In the 20th century, around 200 notable dam failures have occurred in the World, killing about 8000 people. It is notable that dam failures do occur in developed countries too. The biggest catastrophe recorded in this century had occurred in Vaiont in Italy in 1963. The accident killed about 2600 people. Another accident of nearer proportions occurred in India in 1979-- about 2000 persons lost their lives when the Machhu II dam gave way. Other dam failures in the country included Ashti in Maharastra (this dam gave way twice-- in 1883 and 1933), Tigra in Madhya Pradesh (1970), Panchat (1961), Kadakwasala (1961), Nanak Sagar (1967) and Chikkahole (1972). The failure of the Malpasset dam in France in 1959 killed 421 persons and the Baffalo Creek dam in USA in 1972 claimed 125 lives.

IRRIGATION BENEFITS

During the Chief Minister level discussion between the two States, Tamil Nadu has argued that there are 37 other dams, which are similar to Mullaperiyar dam. The details of these dams are at Annexure (E).

It is pointed out here that out of 37 dams 30 are earthen dams. It is also evident from the list that out of the remaining 7 dams, all the six except Mullaperiyar are very small in its capacity, length and height. It is worth mentioning here that the Kadakvasala dam, in Maharashtra, which is second in capacity amongst these seven dams, collapsed in 1961. Its capacity was 86m and height 32.9m, while that of Mullaperiyar is 443.55 and 53.64M. Hence the concern of the State.

OLD VICTORIA DAM

In the meeting the analogous situation of the Old Victoria Dam of Australia was also pointed out. The old Victoria Dam was constructed in 1891 with lime concrete, around the same time when the Mullaperiyar dam was constructed. In 1966 there was considerable seepage in the dam as had been and is being noticed in the Mullaperiyar dam. Certain safety measures like construction of a reinforced concrete slab attached to the upstream water face and a gallery in between the dam and the slab were carried out.

In Mullaperiyar dam, certain other types of strengthening measures including a concrete backing on the downstream face were carried out. However, in 1988 it was observed by the concerned authorities that the strengthening measures carried out in Victoria dam have not worked and the dam did not satisfy the safety standards. The dam was subsequently decommissioned in April 1990.

SEISMIC CO-EFFICIENT

It is found that while assessing the safety of this dam the expert committee had taken the design horizontal seismic co-efficient as 0.12g instead of 0.18g, The value 0.18g is the least recommended value for zone III as per IS 1893-1984 where Kerala is situated. In this context it may be noted that the standing committee set up Government of India for advising the seismic coefficient for the river valley projects recommended a value of 0.24g (Ref: Workshop on Strengthening of dams, CBIP,1989), the Expert Committee chaired by the Member (D&R) and another Chief Engineer of CWC has taken an extreme lower value of 0.12g instead of 0.24g. This extremely low value of 0.12g has incorrectly made the dam 'safe' for water level up to 142 ft. This action of the expert committee is against the guidelines published by the CWC in this regard.

It is evident that if the least seismic co-efficient for zone-III is taken for stability analysis, Mullaperiyar reservoir is not at all safe even to hold water up to the height of 136 ft.

ARGUMENTS PUT FORTH

ARGUMENTS PUT FORTH BY THE KERALA MINISTER FOR WATER RESOURCES N. K. PREMACHANDRAN IN THE MINISTER LEVEL MEETING OF KERALA AND TAMIL NADU IN THE PRESENCE OF UNION MINISTER OF WATER RESOURCES AT NEW DELHI ON 18/12/2006 ON MULLAPERIYAR ISSUE

NEW DAM The Expert Committee formed in 1979 to inspect the ailing dam held a discussion on 25/11/79 at 11 AM in Thiruvananthapuram. In this, one of the long term measures suggested to this issue was as follows:

"A joint team of engineers from Tamil Nadu and Kerala will explore the possibility of locating a new dam within reasonable distance from the existing dam, within a month's time, as an alternative to long term measures for strengthening the existing dam" (Annexure A). In the minutes drafted after the joint inspection of the team of engineers of Tamil Nadu and Kerala, it is stated that "the team feels after inspection of the site AA (1300 ft below the existing dam) and examination of other sites with reference to contour map, that site AA is the nearest possible alignment from geographical considerations without impairing the safety of the existing dam during construction of dam" (Annexure B). The same has been signed by the representative of Tamil Nadu Sri. A. Mohanakrishnan. But, surprisingly, in the memorandum on 'Strengthening Proposal of Mullaperiyar Dam' submitted by the Central Water Commission in 1986 it is stated that it was decided to strengthen the existing dam and the case of construction of new dam was not pursued (Annexure C). In the Expert Committee report (March 2001) filed before the Supreme Court, it is stated that "Although originally it was suggested that the engineers of Tamil Nadu and Kerala will explore the possibility of locating a new dam within a reasonable distance from the existing dam, subsequently this was not found feasible and the proposal was dropped"(Annexure D).

It is not known what made them to say so. The measures taken in this direction are not known. The proposal to construct a new dam is the sustainable solution to assure water to Tamil Nadu and save the life of the downstream population. But from the above it is seen that this suggestion once put forward by the Central Water Commission, has been sidelined, on unknown grounds.

PROBABLE MAXIMUM FLOOD

The argument that Mullaperiyar reservoir is safe even for PMF (Probable Maximum flood) and the fear of overtopping of dam is baseless is actually wrong. It may be stated that for any dam and particularly for masonry or composite gravity dams, flow of water over the top of the dam is the most dangerous situation that a dam can be put in. It results in collapse of the dam as a result of sliding or overturning. Because this is such a crucial safety aspect of the dam, the pattern followed uniformly in all dams in the country is to identify the maximum observed flood that has occurred in the catchment area. Then this figure is significantly boosted up and the PMF identified from this boosted up figure. A table showing explicitly such an exercise done by CWC is given below.

It may be seen from the above table that in the case of Mullaperiyar dam, the maximum flood that took place in the reservoir was in the year 1943 was 8453 cumsecs. However, curiously for the purpose of determining the PMF, Chairman, CWC recommended a figure lower than this maximum amount, namely, 7249 cumsecs. Copy of the Rehabilitation Memorandum dated 24/25 March, 1986 in this regard is enclosed. This recommended figure of Chairman, CWC was again lowered for reasons unknown to 6003 cumsecs. Even with this artificially lowered figure the water would flow over the top of the dam but for the parapets. Not only this but also the siltation in dam would further contribute to the rising of MWL so that water flows over the top of the dam.

It is felt that this has been an exercise in playing with figures to ensure that MWL (Maximum Water Level) comes to 157.7 ft so that FRL (Full Reservoir Level) will come to 152 ft. Just like PMF has a relationship with MWL, MWL has a relationship with FRL. The point that was stated emphatically in the meeting was that if the normal exercise of prudence was adhered to in the Mullaperiyar case in determining the PMF, then the FRL would have come far below 152 ft and possibly close to if not below 136 ft.

If Mulla Periyar Bursts

It is estimated that around 30 lakh people in the districts of Idukki, Alappuzha, Kottayam, Ernakulam and Pathanamthitta will be wiped out if the Mullaperiyar dam bursts.

The potential catastrophe of unimaginable magnitude has been visualised in a documentary produced by the Disaster Management Division of the School of Social Science, Mahatma Gandhi University.

The 24-minute documentary titled `Mullaperiyar, Muzhangunna Maranamani' was released here at the Press Club here on Thursday.

The documentary, which uses computer animation to depict the probable tragedy, shows panic-stricken inhabitants with toddlers in their arms running helter-skelter in the wake of the disaster.

"We wanted to exploit the power of the visual medium in conveying the ferocity of the disaster," said A.V. George, head of the disaster management division. "Our aim is to spread awareness among the public about the magnitude a probable disaster." The documentary directed by Roy Peechatt is based on a book `Mullaperiyar and the threat faced by Kerala' written by Mr. George. Some of the rare photographs taken during the construction of the Mullaperiyar dam as well as its history have been highlighted in the documentary. The presentation also drives home the need of installing early warning systems in regions that are in proximity to the dam.

The documentary would be screened for public in all the five districts that are likely to be hit in the wake of the tragedy, Mr. Peechatt said.

"We are also exploring the possibility of screening the documentary in other States and also in New Delhi.

Full History Of Mullaperiyar dam

1. On 29-10-1886

A lease indenture for 999 years was made between Maharaja of Travancore and Secretary of State for India for Periyar irrigation works by another agreement in 1970, Tamil Nadu was permitted to generate power also.

2. The Mullaperiyar Dam was constructed during 1887-1895 across Periyar River in the then Travancore state (now Kerala) territory after said indenture. The Periyar Dam with full reservoir level of 152 ft. provides for diversion of water from the reservoir through a tunnel to Vaigai basin in Tamil Nadu for irrigation benefits in 68558 ha.

3. In 1979, reports appeared in Kerala Press about the safety of Mulla Periyar Dam. On 25th November, 1979 Chairman, CWC held discussions at Thirvananthapuram regarding strengthening Periyar dam with officers of Irrigation and Electricity, Deptt. of Kerala and PWD of Tamil Nadu. In the meeting, emergency measures to be completed before next monsoon (1980), medium term measures and long-term measures for strengthening of Periyar Dam were decided. One of the emergency measures was to keep the shutters of spillway raised fully to lower the reservoir level to 136 ft.

4. A second meeting under the Chairmanship of Chairman, CWC was held on 29th April 1980 at New Delhi and it was opined that after the completion of emergency and medium term measures in the form of cable anchoring, the water level in the reservoir can be restored up to 145 ft.

5. As per the Memorandum on the Rehabilitation of Mulla Periyar Dam prepared by CWC and forwarded to Tamil Nadu on 25th March, 1986, emergency measures were implemented. In the aforesaid Memo, CWC gave its recommendation about peak flood and size of additional vents to be added in the spillway for implementing remaining emergency measure of providing additional spilling capacity. It also gave its recommendation about the design details of concrete backing on the downstream face of the dam. Besides this, CWC suggested The Government of Tamil Nadu to examine the possibility of raising the top of RCC parapet by another two feet apart from few other suggestions. It was opined in the forwarding note that after completion of the proposed strengthening measures, provision of other additional vents and implementation of other suggestions, Periyar dam would be competent to hold water upto FRL of 152 ft.

6. The matter became subjudice with several petitions in the Kerala and Tamil Nadu High Courts. All these cases were transferred to the Supreme Court which heard the matter and desired in its order dated 28.4.2000 that Hon’ble Minister (WR) may convene a meeting of the Chief Ministers of both the states of Kerala and Tamil Nadu to amicably resolve the issue. .

7.Hon’ble Minister (WR) convened the Inter-State meeting on 19.5.2000 and as decided in the meeting, an Expert Committee under Member (D&R), CWC with representatives from both States was constituted in June 2000 to study the safety of the dam with respect to strengthening of dam carried out by The Government of Tamil Nadu on the advice of Central Water Commission and advise regarding raising of water level in the reservoir beyond 136 ft as a result of strengthening of dam.

8.The Committee in its report of March, 2001 opined that with the strengthening measures implemented, the water level can be raised from 136 ft. to 142 ft. without endangering safety of the dam. Further raising of water level to 152 ft. will be considered after balance strengthening measures are implemented.

9. In the case of Transfer Petition (Civil) No. 779-783/1998 Dr. Subramanian Swamy Vs Tamil Nadu, the Report of the Expert Committee was filed in the Hon’ble Supreme Court on 31.8.2001 and also sent to the State Governments of Kerala and Tamil Nadu.

10 In writ Petition ( C) No. 386 of 2001 (Mulla Periyar Environmental Protection Forum Vs Union of India and Ors) the Supreme Court in its Judgement dated 27.2.2006, permitted the Government of Tamil Nadu to raise the water level of Mulla Periyar dam from 136 ft. to 142 ft. and take up the remaining strengthening measures.

11. Consequent to the aforesaid orders of the Supreme Court of India, the Kerala Government passed the Kerala Irrigation and Water Conservation (Amendment) Act 2006 which received the assent of the Governor on 18th March 2006 which prohibited the raising of water level beyond 136 ft. in the Mulla Periyar Dam as Mullaperiyar Dam was placed under the Schedule of ‘Endangered Dams’.

12.The Government of Tamil Nadu filed a suit No. 3 of 2006 - State of Tamil Nadu v/s State of Kerala and Union of India in the Hon’ble Supreme Court on 31.3.2006 praying for -

(i)Declaration of Kerala Irrigation and Water Conservation (Amendment) Act 2006 passed by Kerala Legislature as unconstitutional in its application to and effect on Mulla Periyar Dam.

(ii)Pass a decree of permanent injunction restraining Kerala from application and enforcing impunged legislation enforcing with or obstructing Tamil Nadu from increasing the water level to 142 feet and from carrying out the repair works as per judgment of Supreme Court dated 27th February 2006.

13. A Review Petition filed by the State of Kerala on 3.4.2006 was dismissed by the Supreme Court on 27.7.2006.

14. In the matter referred to in para 13 above, the Hon’ble Supreme Court has passed an order on 25.9.2006 stating

“the two State Governments independently or with the intervention of the Union of India may try to sort out the dispute, if possible.

15. The Hon’ble Union Minister (WR) convened an inter-State meeting of the Chief Ministers of States of Tamil Nadu & Kerala on Mulla periyar dam issue on 29.11.2006 at New Delhi. Hon’ble Union Minister (WR) further discussed matter with the Minister (WR/PW) from the States of Tamil Nadu & Kerala on18.12.2006. The States of Tamil Nadu and Kerala reiterated their respective stand in the meetings and no consensus could be reached regarding a solution acceptable to both States. The matter is now subjudice.

16. Subsequently, Hon’ble Chief Minister of Tamil Nadu met Hon’ble Prime Minister on 18.12.2007 and Hon’ble Prime Minister suggested him to have a meeting with Hon’ble Chief Minister of Kerala on Mulla Periyar issue. Hon’ble Chief Minister of Tamil Nadu met Hon’ble Chief Minister of Kerala on 19.12.2007 in presence of Hon’ble Union Minister of Water Resources. Further a letter dated 20.12.2007 was received from the Hon’ble Chief Minister of Tamil Nadu mentioning that in the above meeting, Hon’ble Chief Minister of Tamil Nadu suggested to oversee the seepage measurement of the dam by engineers not belonging to either of the two States through CWC and Hon’ble Chief Minister of Kerala agreed to consider them.

17. Later, the Govt. of Tamil Nadu forwarded a letter dt 22/1/08 of Hon’ble Chief Minister of Kerala addressed to Hon’ble Chief Minister of Tamil Nadu wherein it is mentioned that in the meeting dt 19/12/2007 he suggested a joint mechanism to monitor the seepage. The Govt. of Tamil Nadu also enclosed a letter dated 4/2/2008 from Hon’ble Chief Minister of Tamil Nadu addressed to Hon’ble Chief Minister of Kerala wherein it is mentioned that joint monitoring was not discussed in the meeting.

18. CWC was requested to suggest a suitable mechanism for monitoring the seepage and possible structure of the Committee to monitor it. They suggested a nine- member Committee headed by a Chief Engineer, Central Water Commission having representatives from both States for Monitoring the seepage of Mulla Periyar Dam. The composition of the Committee along with terms of reference was sent to Chief Secretary, Government of Tamil Nadu and Kerala vide letter dated 28.4.2008 for their concurrence / suggestions.

19. The Government of Tamil Nadu vide its letter dated 17.6.2008 has sent its comments on the proposed Monitoring Committee stating that the present proposal of the Government of India to constitute a Committee comprising officers from CWC, Tamil Nadu Government and Kerala Government to measure the seepage in Mulla Periyar Dam is not in conformity with the discussion held in the meeting dated 19.12.2007 and proposal will lead to more and more complications and thus not acceptable to Govt. of Tamil Nadu. The Govt. of Kerala vide letter dt 24.2.2009 informed that the stand taken by the Govt. of Tamil Nadu for neutral agency of experts excluding those form Kerala and Tamil Nadu is not acceptable to them.

20. In the meanwhile, Govt. of Kerala has got done hydrological review studies from a professor of IIT, Delhi and has since filed the said hydrological studies report in the Hon’ble Supreme Court on 15.07.08 in connection with Suit No.3 of 2006 filed by the Government of Tamil Nadu. It has been concluded in the report that the Mulla Periyar dam is hydrologic ally unsafe for passing the estimated Probable Maximum Flood (2, 91,275 cusec / 8,248 cusec) with the existing spillway capacity. Comments of Hydrological Studies Organisation, CWC on the report were forwarded to the Govt. Advocate as per instructions of MoWR vide CWC letter dated 13.10.08. CWC has commented that the difference in the adopted values of Design Rainfall (Storm) depth, Time distribution of rainfall, Unit hydrograph & Infiltration rate have resulted in estimation of higher flood peak (PMF) and the said studies by the IIT Professor does not appear to be well founded.

21. Meanwhile the Government of Kerala constituted a Committee in May 2009 which submitted its report in June, 2009. The Committee suggested mapping of the underwater area, installation of highly sensitive computer operated Seismograph and construction of a new Dam downstream of existing dam. The Committee has also opined that the dam has reached such a deteriorated condition that no amount of rectification work could salvage it to a safe and healthy condition. Keeping in view this report, Minister (WR) advised Chairman, CWC in July, 2009 to constitute a team of officers to visit the dam and assess the present condition of the Mulla Periyar dam and look into the issues raised in the report of the above Expert Committee. The team had proposed a visit to the dam from 22-25 July, 2009 and the conveniences of the Government of Kerala and Tamil Nadu for the visit were sought. The Government of Tamil Nadu agreed to the proposed visit but the Government of Kerala requested for postponement of the proposed visit because of torrential rains. Thereafter, the visit could not materialize.

22. Thereafter, Secretary (WR) convened a meeting on the Mulla Periyar Dam on 31.7.2009. The meeting was attended among others by Principal Secretary, PWD, Tamil Nadu and Additional Chief Secretary, WRD, Kerala. In the meeting the representative of Kerala informed that the Kerala Govt. visualizes construction of new dam as the only feasible solution and they have started survey and investigation for a new dam at an alternate site downstream of the existing dam and they may also consider the construction of a new dam at their own cost. Representative of Kerala stated in the meeting that the Govt. of Kerala also recognizes the established uses of water from the dam by Tamil Nadu as per the existing agreement between the two States and will continue the same after the construction of a new dam. In the said meeting the representative of Govt. of Tamil Nadu informed that the Govt. of Tamil Nadu would examine the proposal of the Govt. of Kerala for new Dam after the same is formally received from them. In view of this, Hon’ble Minister (WR) vide DO dated 26.08.2009 requested Hon’ble Chief Minister, Kerala to send the proposal in this regard to the Govt. of Tamil Nadu for their consideration.

23. Later, Govt. of Tamil Nadu vide letter dated 14.9.09 mentioned that as regards the decision that has emerged in the meeting, to examine the proposal of the Kerala Government for the construction of a new dam by Tamil Nadu Government, the Government of Tamil Nadu 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. They also mentioned that Hon’ble Chief Minister of Tamil Nadu in his letter dated 13.07.09 to Hon’ble Chief Minister of Kerala had mentioned that Kerala Govt. may not raise the issue of new dam any more.

24. The Govt. of Kerala vide letter dated 26.9.2009 sent comments on the minutes of the meeting dated 31.7.2009 mentioning that the statement “The Govt. of Kerala also recognizes the established use of water from the dam by the Tamil Nadu as per the existing agreement between the two States and continue the same after the construction of new dam” is not acceptable. What was mentioned in the meeting was that Kerala is willing to give water to Tamil Nadu.

25. Further, Hon’ble Supreme Court heard the issues related to Mulla Periyar Dam on 10.11.2009 and passed the order that, “As the case involves the resolution of said questions, the suit may be placed before the Hon’ble Chief Justice of India for necessary directions for placing it before a constitution Bench.

The contesting parties shall maintain status quo in respect of Mulla Periyar Dam as existing today. However, order of status quo will not be an impediment for the plaintiff (State of Tamil Nadu) to carry out maintenance and repairs for proper upkeep of the said Dam.”

26. The case was heard by five judges on 18.2.2010 and the Court directed Central Govt. to constitute an empowered Committee in this regard which would hear the parties to the suit on all issues that will be raised before them, and furnish a report, as far as possible, with in six months from their constitution.

27 Following the order of Hon’ble Supreme Court dated 29.02.2010, Centre (MoWR) has constituted an Empowered Committee vide Notification dated the 30th April, 2010. The Committee started its functioning and was to submit its report within six months period. Further, Supreme Court vide its order dated 20th September, 2010 has extended the term of Committee by a further period of six months. Therefore, implementing the said directions of the Supreme Court, the Central Government extends, the terms of Empowered Committee for a further period of six months w.e.f. 30th October, 2010 vide Notification dated the 28th October, 2010.

Legal Aspects

Justice A.S. Anand Committee

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.

Current status of The Dam

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 wants 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 for the final report.

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. Together with safety concerns, now the Kerala government argues that if the water level is increased to 142 feet, wide forest areas that are inhabited by conserved flora and fauna will be inundated. Tamil Nadu insists that the non-implementation of Supreme Court Order to increase water level by Kerala is the first issues tobe tackled. 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 pointed out 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.

Tamilnadu Government's stand

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 news 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."

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 km2). 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 km2).

An article written in a 2000 Frontline magazine 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 an other 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.

Disputes About the Dam

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 dam and especially for the thickly populated 4 districts downstream. Twenty six tremors have occur ed near the premises of the dam in the last nine months. IIT Roorkee report states that dam can not withstand earth quakes of magnitude 6 and above. It is a serious matter affecting lives and assets of millions of people. Kerala is willing to construct new dam and It is willing to provide water for Tamil Nadu. But still TN is opposing the move fearing that they will lose control over the functionality of Dam. The dispute is going to affect lives of millions staying in the three districts near the dam.

The Lease Agreement

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 British Empire.

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 become heavily inhabited, as Kerala has a very high population density.

Safety Concerns

In 1979, safety concerns were raised by Kerala Government after a minor earthquake, after which a few leaks were detected in the 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. Water level in the 116-year-old Mullaperiyar dam rose to 135.8 feet.

History Of Mullaperiyar

Lease

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. 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 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.

Dam construction

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 of Travancore, 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.

Mullai Periyar Dam and River

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

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.

Mullaperiyar Dam

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.