Murchison Dam was constructed between 1978 and 1982 and forms Lake Murchison, which is a diversion storage that discharges water into Lake Mackintosh via the underground Sophia tunnel.
Hydro Tasmania is increasing the size of the spillway on Murchison Dam in response to long-term predictions from the Bureau of Meteorology.
According to the Bureau, previously rare, very large rainfall events are occurring more frequently. The steep-sided nature of the Murchison Dam can result in rapid water-level rise during periods of intense rainfall. A larger spillway will allow the dam to safely weather the largest, most severe rainstorm event.
The upgrade to the dam involves constructing a three-metre concrete wall on the crest of the dam and raising the inside wall of the spillway by up to five metres.
Works began on site in October 2019 and will continue for 12 to 15 months until late 2020. During this period the Murchison Dam Road, south of Hean Street, will be temporarily closed to all public vehicles to ensure public safety.