Also at the southern end of the Lake Pedder, the Scotts Peak Dam impounds the Huon River.

At 100% capacity the dam wall holds back 2,937,930 megalitres (103,752×10^6 cu ft) of water.

The Lake Edgar Fault is a 30-kilometre (19 mi) long north–south trending scarp that occurs within the boundary of the Southwest National Park.

The scarp traverses the button grass of the Huon Plains and is notable because faulting resulted in the defeat of westerly flowing drainage and the consequent formation of the fault-bound sag pond of Lake Edgar.

[5][6][7][8][9] In 2002 it was reported that a dam safety manager from Hydro Tasmania, was confident that the eventuality of the Edgar dam being destroyed by an earthquake was an extremely remote possibility, with a University of Tasmania Geophysicist agreeing that the risk of collapse was remote.