Tasmania’s Lake Pedder overflow does not pose threat to life or property

In almost three decades, Lake Pedder in Tasmania is set to overflow for the first time. In the last 24 hours heavy rains lashed the region and the lake’s water level has risen 20cm. With capacity now at 99 percent, the lake is set to overflow on Wednesday.

“While this is a novel event involving an iconic lake, we have no concerns about Lake Pedder reaching capacity for the first time in more than a quarter of a century. We’ve been monitoring the situation in recent weeks, and are well prepared,” Hydro Tasmania's Dam Safety Manager, Chris Topham, said in a statement.

Lake Pedder is expected to reach full capacity and spill for the first time since November 1988. Heavy rains have pushed the water level from 87 percent to 99 percent. When the water level reaches full supply level in the next 12 hours, Hydro Tasmania will follow standard operating procedures and open the Serpentine Dam outlet gate.

Opening the gate is expected to create a controlled spill into Macquarie Harbour. It poses no property damage or safety risk.

“Opening the gate later today will release a controlled flow into Macquarie Harbour, via the Serpentine and Gordon Rivers. No-one using Macquarie Harbour should notice any difference from the controlled spill. However we've advised TasPorts and all Macquarie Harbour fish farms as a courtesy,” Topham added.

Carrying out a controlled spill is the best remaining option to control Pedder’s water level. Water transfer has already started from Lake Pedder to Lake Gordon at maximum capacity. Lake Pedder filled up by 12 percent in 24 hours.

Flooded Lake Pedder has a surface area of approximately 242 square kilometres and is the largest freshwater lake in Australia. Once a natural lake, Lake Pedder is now a man-made impoundment and diversion lake located in the southwest of Tasmania, Australia.