Mullaperiyar Dam is build over the headwaters of the Periyar River in Kerala, India. The Periyar National Park, Thekkady is located close to the Periyar reservoir. The backwaters of this dam form this park. Government of Tamil Nadu operates the functions of the park and according to a 999-year lease agreement the dam was built during erstwhile British colonial rule.

The name of Mullaperiyar Dam is derived from a portmanteau of Mullayar and Periyar. As the dam is located at the convergence of the Mullayar and Periyar Rivers, the river was called Mullaperiyar.

The structure of the Mullaperiyar Dam was approved by the British during the colonial rule to redirect the waters of the west-flowing Periyar River eastwards, through the construction of a granite dam, and channelizing the water from the reservoir through a tunnel cut across the division and Western Ghats to the dry rain shadow regions of Theni, Madurai District, Sivaganga District and Ramanathapuram districts of Tamil Nadu.

The Princely State of Travancore was compelled to approve a treaty in 1886, thus in regard to lease the dam site for 999 years to the then Madras government. The agreement of lease provided the British the rights over the reservoir of the Mullaperiyar Dam and also across its catchment, for an annual rent of Rs. 40,000.

The British Army Engineering corps for the Travancore kingdom had built the dam. After the first dam being washed away by floods, a second stonework dam was constructed in 1895. Unlike the earlier calculations, the government of Tamil Nadu finally decided to make the storage capacity to be 136 feet to 142 feet. This measurement also was in favor of the safety concerns for the more than hundred-year-old bridge and the densely populated districts downstream.

History of Mullaperiyar Dam
After Indian independence, the areas of the states were shuffled and new territories were also formed. The area surrounding the location of the dam was merged with Kerala State. Tamil Nadu used the water from the Mullaperiyar Dam and river Periyar for extending irrigation requirements and later for power generation on the basis of unofficial agreements between the governments of the two states.

The Idukki Hydroelectric project is located 30 km downstream after its completion 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 became heavily inhabited and in 1979. Few leaks were noticed in the Mullaperiyar dam and the then Tamil Nadu government lowered the storage level to the present 136 feet after negotiating with the Kerala Government.

Tamil Nadu Government looks after the Mullaperiyar Dam and its surrounding areas. The Supreme Court of India allowed for the storage level of Mullaperiyar Dam to be raised to 142 feet.