The dam is a double-curvature arch structure, meaning it curves both horizontally and vertically to transfer water pressure to the canyon walls.
The project was built with technical assistance from the Canadian government under the Colombo Plan.
The Idukki reservoir has a live storage capacity of 1,996 million cubic meters.
No spillway gates were installed on the main arch dam; flood management is conducted through the separate Cheruthony Dam.
The dam construction required 450,000 cubic meters of concrete.
The arch dam base width is 19.8 meters, tapering to 7.6 meters at the crest.
The project supports the Moolamattom Power Station, which is located deep inside a mountain cavern.
Surrounding the dam is the Idukki Wildlife Sanctuary, covering 105 square kilometers of evergreen forest.
Idukki Dam is a double curvature arch dam constructed across the Periyar River between the Kuravan and Kurathi hills. Standing at 168.91 meters, it ranks as one of the highest arch dams in Asia. It acts as the primary reservoir for the Idukki Hydroelectric Project, which supplies a significant portion of Kerala's electricity. The concrete structure does not contain a spillway; instead, water is released through the Cheruthony Dam, which sits adjacent to the main arch dam. The reservoir created by these structures, known as Idukki Lake, covers approximately 33 square kilometers. The facility is a joint venture of the Kerala State Electricity Board and is a restricted area due to its critical status as a power installation. Visitors are permitted access to limited designated zones under strict security supervision. The dam site serves as a vital component of the state's irrigation and power grid infrastructure.
The designated visitor viewpoint area near the entrance (when authorized).
Bring a valid government-issued photo ID as it is mandatory for entry security checks.
Mobile phones and cameras are strictly prohibited at the dam site; leave these in your vehicle.
Check for local weather updates, as the area experiences heavy monsoon rainfall that can limit site access.
Do not attempt to access the dam premises during extreme weather or heavy monsoon alerts, as security gates are frequently locked for safety.
The dam is often closed to tourists during peak monsoon months or for security reasons; typically remains open on most other days.
Strict security protocols apply; follow all instructions from onsite guards, and do not attempt to film or photograph restricted areas.
