The Ponmudi Dam , in the Idukki district , State of Kerala, India, is a hydroelectric project constructed across the Panniar River, a tributary of the Periyar River which is the longest river in Kerala. Built in 1963, it has a length of 294 metres (965 ft). The hydropower component of the dam has an installed capacity of 30 MW with firm power of 17 MW, generating 158 GWh annually.The Ponmudi Dam , in the Idukki district , State of Kerala, India, is a hydroelectric project constructed across the Panniar River, a tributary of the Periyar River which is the longest river in Kerala. Built in 1963, it has a length of 294 metres (965 ft). The hydropower component of the dam has an installed capacity of 30 MW with firm power of 17 MW, generating 158 GWh annually. This dam is built across river Panniar on the way from Adimali to Rajakkad and the water from the reservoir is used for power generation. The view from the dam-the small settlements below and the water in the reservoir on the ot...