HYDRO TASMANIA SAYS THAT increased releases from the Trevallyn dam to improve marine life and water quality in the Tamar river will cost about US$437,000 due to lost energy production.

When the dam was built in 1955, Hydro Tasmania’s license required it to release 0.43m3/sec of water to flow into the river, but recent studies have shown in stream flow requirements of 1.5m³/sec.

The Trevallyn Power Development is a run-the-river hydroelectric scheme built by Hydro Tasmania outside the Central Highlands, consisting of a concrete gravity dam, which diverts water through a tunnel to the Trevallyn Power Station.

The four generators at the power station have a combined capacity of 80MW and operate on a 112m head, with its tailrace water flowing out into the Tamar at sea level.