Koyna Dam, Hydroelectric dam in Maharashtra, India

The Koyna Dam crosses the river valley with a concrete structure that holds back the waters of Shivsagar Lake in the Western Ghats of Maharashtra. The facility includes turbine halls at the base and a row of spillway gates along the crest to manage seasonal rainfall.

Built after Indian independence as part of the Koyna Hydroelectric Project, the dam was strengthened in two stages: the non-overflow section in 1973 and the spillway section in 2006. The 1967 Koynanagar earthquake cracked the structure; cracks were grouted and internal holes drilled to relieve hydrostatic pressure in the dam body.

The reservoir behind the dam is called Shivsagar Lake, and the Marathi sources note that the Koyna, Solshi and Kandota rivers meet at Tapola village at its far end, where boating and other tourist facilities operate. The Koyna Wildlife Sanctuary runs along the reservoir's shore.

Visitors can view the reservoir and surrounding hill ranges from public vantage points, with the monsoon period between June and September bringing peak water levels. Access roads wind through hilly terrain, so plan extra travel time for arrival and departure.

Researchers drilled boreholes near the structure to monitor earthquake activity that began after the reservoir filled. These measurements help understand how large water bodies can influence geological stress in the earth's crust.