Name, Purpose And Design

Earlier known as the Periyar dam as it was basically meant to dam the Periyar river, the present name Mullaperiyar is derived from a portmanteau of Mullayar and Periyar, at the confluence of which the dam is located^. The geography of the Periyar river which flows westward into the Arabian Sea had suggested to engineers in the first decade of the nineteenth century that the river waters could be diverted eastward to flow towards the Bay of Bengal and provide water to the arid Madurai region of Madras Presidency which was in dire need for a greater supply than the small Vaigai River could give. The dam, finally constructed in 1895, created the Periyar Thekkady reservoir, from which water was diverted eastwards to Tamil Nadu via a tunnel enabling the water to join the Vaigai River which was dammed to provide a source for irrigating large tracts of Madurai. Initially the dam waters were used only for irrigation. Later, the Periyar Power Station in Lower Periyar, Tamil Nadu was built which generates hydro-electricity from the diverted waters.
The Mullaperiyar is a masonry gravity dam, which uses its weight and the forces gravity to support the reservoir weight and remain stable. The main dam has a maximum height of 53.6 m (176 ft) and length of 365.7 m (1,200 ft). Its crest is 3.6 m (12 ft) wide while the base has a width of 42.2 m (138 ft). It is comprised of a main dam section, spillway section on its left and an auxiliary (or "baby dam") to the right. Its reservoir can withhold 443,230,000 m³ (359,332 acre·ft) of water, 299,130,000 m³ (242,509 acre·ft) of which is active (live) storage.^[2][1]