Loading…
A 19th-century masonry dam located in Kerala but operated by Tamil Nadu under an 1886 lease, and the subject of a long-running inter-state dispute over water level and dam safety.
The Mullaperiyar Dam is a masonry gravity dam at Thekkady in the Idukki district of Kerala, built at the confluence of the Mullayar and Periyar rivers at an altitude of 881 metres in the Cardamom Hills of the Western Ghats. Construction began in 1887 and was completed in 1895, making it one of the oldest dams in India. Its purpose is to divert water from the west-flowing Periyar into the Vaigai basin in Tamil Nadu through tunnels cut across the Western Ghats. The dam stands on Kerala's territory but is operated and maintained by Tamil Nadu under a lease agreement of 1886, an arrangement that lies at the heart of a long-running dispute between the two states.
Type: PhenomenonType and location — a masonry gravity dam at Thekkady, Idukki district, Kerala, at an altitude of 881 metres in the Cardamom Hills of the Western Ghats.
Rivers — built at the confluence of the Mullayar and the Periyar, the longest river in Kerala.
Construction — begun in 1887 and completed in 1895 by the British Corps of Royal Engineers under the leadership of Pennycuick.
Purpose — to transfer water from the Periyar to the Vaigai river basin in Tamil Nadu for irrigation and power generation.
Beneficiary districts — Theni, Madurai, Sivaganga and Ramanathapuram in Tamil Nadu, reached through tunnels cutting across the Western Ghats.
Unusual arrangement — the dam lies in Kerala but is operated and maintained by Tamil Nadu.
Power generation — the water also generates electricity for Tamil Nadu through associated hydroelectric plants.
Frequency: Inter-state river water disputes appear regularly in UPSC Prelims and Mains GS Paper 2, and Mullaperiyar is among the most frequently cited examples.
The dam originates in a colonial-era engineering project designed to solve a geographic problem: Kerala's Periyar flows west into the Arabian Sea while the rain-scarce districts of southern Tamil Nadu lie east of the Western Ghats. Diverting the Periyar eastwards required both a dam and tunnels through the mountains, and the agreement that made it possible was concluded between a princely state and the colonial government — which is precisely why its status after independence became contested.
A lease indenture for 999 years is made between the Maharaja of Travancore and the British Secretary of State for India for the Periyar Irrigation Works.
Construction of the dam begins under the British Corps of Royal Engineers, led by Pennycuick.
The dam is completed.
Kerala passes the Irrigation and Water Conservation (Amendment) Act, 2006, prohibiting the water level from being raised beyond 136 feet.
Tamil Nadu files a suit in the Supreme Court seeking a declaration that the Kerala Act is unconstitutional and asking that the level be allowed to rise to 142 feet.
The Supreme Court permits storage up to 142 feet.
A Supervisory Committee is tasked with overseeing the dam, including directions on the maximum water level.
The Mullaperiyar dispute is difficult because the risk and the benefit fall on different sides of a state boundary. The reservoir and the dam structure sit in Kerala, so any failure would flood Kerala's territory and population. The water, however, irrigates Tamil Nadu's Theni, Madurai, Sivaganga and Ramanathapuram districts and generates power for Tamil Nadu, so the benefit accrues entirely to the other state. Kerala therefore emphasises the dam's age and structural safety and argues for a lower water level, while Tamil Nadu emphasises its contractual entitlement under the 1886 lease and the dependence of millions of farmers on the supply. Because neither argument answers the other — safety and entitlement are different kinds of claim — the dispute has required repeated judicial intervention rather than negotiated settlement.
It is like a water tank standing on one neighbour's roof but serving the other neighbour's house. The owner of the roof worries about it collapsing; the user worries about losing the supply. Both concerns are legitimate and neither cancels the other.
Thekkady, Idukki district, Kerala
Confluence of the Mullayar and Periyar
881 metres, Cardamom Hills, Western Ghats
1887 to 1895
Pennycuick, British Corps of Royal Engineers
999 years, made 29 October 1886
142 feet
Theni, Madurai, Sivaganga and Ramanathapuram
Masonry gravity dam at Thekkady, Idukki district, Kerala — operated by Tamil Nadu.
At the confluence of the Mullayar and Periyar rivers; the Periyar is Kerala's longest river.
Built 1887-1895 under Pennycuick of the British Corps of Royal Engineers.
Lease of 999 years made on 29 October 1886 between Travancore and the British Secretary of State.
Diverts water from the Periyar to the Vaigai basin in Tamil Nadu through tunnels across the Western Ghats.
Kerala's 2006 Act sought a 136-feet cap; the Supreme Court permitted 142 feet in 2014.
A Supervisory Committee oversees the dam and the maximum water level.
It is located at Thekkady in Idukki district, Kerala, but is operated and maintained by Tamil Nadu under a lease agreement made in 1886.
It is built at the confluence of the Mullayar and the Periyar, the longest river in Kerala. Water is diverted from the Periyar into the Vaigai basin in Tamil Nadu.
Kerala's Irrigation and Water Conservation (Amendment) Act, 2006 sought to cap the level at 136 feet on safety grounds. Tamil Nadu challenged this, and in 2014 the Supreme Court permitted storage up to 142 feet.
It was built between 1887 and 1895 by the British Corps of Royal Engineers under the leadership of Pennycuick.