This was only compiled by me from various resources from inter net.
Thankx to - Wikipidia.com
Periyar River : The Periyar River is the longest river in the state of Kerala with a length of 244 km. It is one of the few perennial rivers of Kerala. It generates the major chunk of electrical power for the state from its many big and small hydroelectric projects. Its water provides drinking water for the major towns.
It originates in the Western Ghats range near the border with Tamil Nadu state Flow It flows north through Periyar National Park into Periyar Lake. From the lake the river flows northwest through the village of Neeleeswaram to empty into Vembanad Lake on the Arabian Sea coast.
Periyar Lake, An artificial reservoir created in 1895 by the construction of a dam across the river.
Mullaperiyar Dam Mullaperiyar Dam is constructed over the headwaters of the Periyar River river in Kerala, India.
The Periyar National Park, Thekkady is located around the Periyar reservoir formed by the backwaters of this dam. Although the dam is situated at Thekkadi in Kerala, it is owned and operated by the Government of Tamil Nadu.
The Dam Was Build To divert the water from the reservoir towards East side ( Tamil Nadu) through 4 tunnels which cut across the watershed and Western Ghats to the arid rain shadow regions ( leeward side of wester Ghats, Tamil Nadu) of Theni, Madurai District, Sivaganga District and Ramanathapuram Districts of Tamil Nadu .
Who Build The Dam and When:?
The structure was conceived by the British during the colonial rule The Periyar dam was built in 1895 by John Pennycuick, who implemented a plan proposed over a century earlier by Pradani Muthirulappa Pillai of Ramnad. The dam was built by the British Army Engineering corps. The first dam was washed away by floods, and a second masonry dam was constructed in 1895. Agreement Of 1886 The Princely State of Travancore signed a treaty in 1886 to lease the dam site for 999 years to the then Madras government. The lease provided the British the rights over "all the waters" of the Mullaperiyar and its catchment, for an annual rent of Rs. 40,000. The dam was built by the British Army Engineering corps. The first dam was washed away by floods, and a second masonry dam was constructed in 1895.
Problem : Vaigai gets major feed from the Periyar dam in Kumuli in Kerala. As the Keral government is refusing to increase the storage level, Vaigai river ends up dry very often. The water never reaches Madurai, let alone flowing into places past Madurai.
Historical background of the dispute After Indian independence, the states were reorganised and the area surrounding the location of the dam was merged with Kerala State. Tamil Nadu continued to use the water from Periyar for extending irrigation facilities , and later for power generation on the basis of informal agreements between the governments of the two states. In 1970 the Kerala and Tamil Nadu governments signed a formal agreement to renew the 1886 treaty almost completely. The Idukki Hydroelectric project, located 30 km downstream was completed in 1976 by the Kerala government, is still the major resource for irrigation and electricity needs of Kerala. After Independence the areas downstream of the Mullaperiyar had started to become heavily inhabited. In 1979, safety concerns were raised by Kerala Government after a minor earthquake, after which a few leaks were detected in the Mullaperiyar dam. A state agency had reported that the structure would not withstand an earthquake above magnitude 6 on the Richter scale. The then Tamil Nadu government ( I thinnk It is MGR) lowered the storage level to the current 136 feet (from 142.2 feet) at the request of the Kerala Government to carry out saftey repairs, after which it was suggested that the storage level could be raised to the full reservoir level of 152 feet. Meanwhile, the Tamil Nadu government had increased its withdrawal from the reservoir, with additional facilities to cater to the increased demand from newly irrigated areas. How Tamil Nadu Get Affected One article estimates that "the crop losses to Tamil Nadu, because of the reduction in the height of the dam, between 1980 and 2005 is a whopping Rs. 40,000 crores. In the process the farmers of the erstwhile rain shadow areas in Tamil Nadu who had started a thrice yearly cropping pattern had to go back to the bi-annual cropping.". Link Between Idukki Dam and Periyar Dam -
A possible Reason for not allowing to raise the Dam working level. The Idukki Dam is built on the Periyar River on 1975, over the Kuravan and Kurathi Hills Kerala. At 167.68 meters, it is highest arch dam in Asia. It started generating power on 4 October 1975. The surplus over flow from Periyar Dam is the feed for Idukki Dam hydro power generation, the over flow from periyar will be less if the working height of the periyar is more, so, surplus water from the Periyar dam failed to fill up the newly-constructed Idukki dam for three consecutive years, since Kerala have acute power shortage the restriction in the level of the Periyar dam to 136 feet will allow the Idukki Dam power plant to work in full capacity.