Thiruvananthapuram: The construction of the 2.5-kilometre main tunnel for the Mankulam Hydropower Project is set to complete by 10 October, four months ahead of schedule. This tunnel, carved through massive rock formations, plays a crucial role in the hydropower project.
Designed to generate 80 megawatts (MW) of electricity in two phases, the Mankulam Hydropower Project will produce 40 MW in the first phase. The tunnel, measuring 3.6 metres in width, extends up to the surge well, which regulates water pressure, and has now entered its final stage of construction.
Water from the dam near Mankulam town will flow through this tunnel to the power generation house. The surge well, which opens at the top of the tunnel, will reach a depth of 90 metres with an 8-metre radius.
The remaining work includes completing a one-kilometre pressure shaft with a diameter of three metres, of which approximately 800 metres have already been constructed.
Additionally, 160 metres of the 51-degree inclined tunnel, which replaces traditional penstock pipes, are finished, while another 230 metres remain to be completed.
Approximately 40 per cent of the civil works for the project are complete. The dam, standing 500 metres high and 200 metres wide, ranks among the largest built by the Kerala State Electricity Board (KSEB) in recent years. It spans the Melacherry River, a tributary of the Periyar.
After generating power, the water released from the Mankulam Dam will flow to the proposed site of the Pooyamkutty Dam. In the next phase, water from Lower Rajamala and Kadalar will be channelled through a six-kilometre tunnel to generate an additional 40 MW of power.
Project Overview
The first phase of the Mankulam Hydropower Project began in 2022 in Idukki and is expected to cost approximately Rs 600 crore, with Rs 295 crore allocated for civil works.
The PES-KSR consortium has secured the contract for the project, which has a target completion date of May 2026. However, KSEB officials have indicated that the project might be extended by another year. Once the first phase is complete, the project is expected to generate 10.1 crore units of power annually.