UNSUSPECTING visitors could be forgiven for thinking someone has pulled the plug and accidentally drained the man-made Lake Meadowbank near Ouse. In fact, the water in the Hydro storage has been deliberately lowered two metres below its usual level to allow work to start on the replacement of nearly 60-year-old spillway gates on top of the Meadowbank Dam.
Hydro Tasmania says this important maintenance work will ensure Meadowbank can continue to generate renewable energy, protect surrounding communities from floods and keep water levels constant. Meadowbank Power Station started operation in the late 1960s and in an average year it generates 187 gigawatt-hours of hydro-electricity, enough to light up Hobart.
The power station uses water from the River Derwent, held in the Lake Meadowbank reservoir which is located between Hamilton and Ouse in the upper Derwent Valley. The spillway on top of the Meadowbank dam wall is automatically controlled by two crest gates. Each gate measures 6 x 35 metres and is controlled by 10 hydraulic cylinders. When the lake is full, these gates hold back approximately 60 million tonnes of water. They play a critical role in power generation and safety, and are due for replacement.
To allow this work to be carried out, Lake Meadowbank was lowered two metres below its usual level from January 29. In mid-March, the lake will be lowered a further four metres while Hydro Tasmania tests the new hydraulic cylinders and control system. The lake is expected to return to normal levels by May.
During works, the lake is too low for the Dunrobin boat ramp to be used and this facility has been temporarily closed. To explore alternative Hydro Tasmania sites nearby, visit www.hydro.com.au/findasite/
Main picture: Granville “Granny” Williams, of Maydena, surveying the scene at Lake Meadowbank earlier today, where the water level has been lowered by two metres.