LocationLatitude : 9⁰ 48′ 35 ” N
Longitude: 77⁰ 06′ 20” E
Dam Features
Type of DamConcrete- Gravity
PanchayathErattayarClassificationMH ( Medium Height)
VillageErattayarMaximum Water Level (MWL)EL 754.38 m
DistrictIdukkiFull Reservoir Level ( FRL)EL 754.38 m
River BasinPeriyarStorage at FRL5.352 Mm3
RiverPerinjamkutty ( Tributory of Periyar)Height from deepest foundation19.81 m
Release from Dam to riverErattayarLength146.3 m
Taluk through which release flowsThodupuzha, Udupanchola, Devikulam, Kothamangalam, Muvattupuzha, Kunnathunadu, Aluva, Kodungalloor, ParavurSpillwayOgee type – 2 Nos. Radial gates, each of size 7.62 x 6.10 m
Year of completion1975Crest Level748.28 m
Name of ProjectIdukki HEPRiver Outlet1 No. vertical lift type, 2.44 x 1.83 m
Purpose of ProjectHydro PowerOfficers in charge & phone No.Executive Engineer, Dam Safety Division No. II, Vazhathope, Idukki (Dist.), Kerala, PIN- 685602 Phone- 9446008425
Installed capacity of the Project780 MWAssistant Executive Engineer, Dam Safety Sub Division, Vazhathope , Idukki ( Dist.), Kerala , PNI-685602 Phone-9496011961
Project Identification Code ( PIC)KL29MH0038

Idukki HE Project- Stage III- Kallar-Erattayar diversion scheme envisages creation of two forebays by means of diversion dams, one in river Kallar of storage capacity 28 Mcft.( 0.793 MCM) and another in river Erattayar of storage capacity 189 Mcft. (5.352 MCM) in the upper reaches of river Perinjamkutty a tributary of Periyar. Water from Kallar is diverted to Erattayar through a tunnel 2735.58 m long. Diversion of water from Erattayar forebay to Idukki reservoir is through another tunnel 3771.9m long.