Idamalayar Dam is a multipurpose concrete gravity dam located at Ennakkal between Ayyampuzha and Bhoothathankettu in Ernakulam district of Kerala on the Idamalayar, a tributary of the Periyar River in Kerala, South India.

[3][4] The large reservoir created by the Idamalayar Dam is operated by the Kerala State Electricity Board to augment its peak power generation requirements.

Edamalayar originates in the Anamala Hills in Ernakulam district itself at elevation of 2,520 metres (8,270 ft).

The river is a perennial source draining a catchment area of 381 km2 (147 sq mi) with a topography of high relief.

The catchment receives annual rainfall of 6,000 millimetres (240 in), 90% of which occurs during the monsoon months of June to September.

[8] The dam built across the Idamalayar River is a gravity concrete structure with a total height of 102.80 metres (337.3 ft) above the deepest foundation level with a length of 373 metres (1,224 ft) at the crest level.

[9] Instrumentation is provided in the Idamalayar Dam and the observations carried out are analysed regularly to monitor the safety of the structure.

[10][11] Idamalayar project is a low head Hydro Electric Scheme located in Ernakulam District.

[16] A High Level Committee set up by the Government of Kerala, which examined this issue, observed that the Idamalayar Dam project has been the "victim of recurring and long inertial periods of labour unrest".

The government appointed Justice K. Sukumaran to inquire into allegations related to the Idamalayar and Kallada dam construction contracts.

Based on his report, Minister R. Balakrishna Pillai and others were prosecuted by a Special Court.

The birds found are: heart-spotted woodpecker, common flameback, black rumped flameback, greater flameback, crimson-fronted barbet, Malabar grey hornbill, Malabar trogon, dollarbird, Oriental dwarf kingfisher, stork-billed kingfisher, common hawk cuckoo, plum-headed parakeet, Malabar parakeet, white-rumped needletail, brown-backed needletail, jungle owlet, green imperial pigeon, emerald dove, grey-fronted green pigeon, river tern, brahminy kite, hornbill, grey-headed fish eagle, black eagle, Oriental honey buzzard, rufous-bellied hawk-eagle, little heron, Asian openbill, fairy bluebird, small minivet, bar-winged flycatcher-shrike, black-naped monarch, Asian paradise flycatcher, Malabar whistling thrush, rusty-tailed flycatcher, white-bellied blue-flycatcher, Indian blue robin, chestnut-tailed starling, velvet-fronted nuthatch, great tit, dusky crag martin, red-rumped swallow, Asian koel, yellow-browed bulbul, Wayanad laughingthrush, dark-fronted babbler, rufous babbler, Nilgiri pipit, yellow-billed babbler, brown-cheeked fulvetta, plain flowerpecker, crimson-backed sunbird, and little spiderhunter.