The Water Network
The ACT draws its water supply from three separate catchment systems:
- The Cotter River catchment, located within the ACT.
- The Queanbeyan River catchment, located wholly within NSW.
- Murrumbidgee River.
Three dams have been constructed within the Cotter River catchment and one in the Queanbeyan River catchment.
The Cotter River Catchment
The upper reaches of the Cotter River catchment are within the Namadgi National Park and the catchment lies within the ACT. The river itself starts high up the Brindabella Mountains and is fed by rainfall and melting snow. This is a protected catchment with no farms or houses and with restrictions on activities within the catchment in order to protect the quality of the water.
The water from this catchment is of good quality, although the catchment suffered severe damage during the January 2003 bushfires, which has impacted on the quality of the water. The loss of vegetation in the catchment meant that the quality of water running off the catchment was more variable than it was prior to the bushfires. Immediately after the fires, there was an increase in the turbidity (cloudiness) as well increases in iron and manganese in the water. Significant remediation works have been undertaken in the lower catchment to minimise these impacts.
There are three dams located on the Cotter River: Corin, Bendora and Cotter. Corin Dam is the most-upstream of the three. Water stored in the Corin Dam is released downstream into the Cotter River and flows down the river to Bendora Dam. From Bendora Dam a large diameter pipeline carries water by gravity to the treatment plant on Mount Stromlo (to the west of Canberra). The Bendora Gravity Main is 20 kilometres long and has the capacity to carry 310 million litres of water per day.
Cotter Dam is the largest and lowest dam on the Cotter River. As the Cotter Dam is lower than the Mount Stromlo Water Treatment Plant, water from this reservoir must be pumped from the historic Cotter Pump Station, to the treatment plant.
The Queanbeyan River Catchment
Canberra’s water supply system also includes Googong Dam on the Queanbeyan River to the southeast of Queanbeyan. As Googong Dam is fed by water from a rural catchment which includes farmlands and small communities, the water quality from this catchment can be variable and requires extensive treatment in order to meet drinking water quality requirements. Water from the Googong Dam, once treated at the Googong Treatment Plant, is pumped to Canberra and Queanbeyan.
The use of water from the Murrumbidgee River commenced in May 2007 from a location near the Cotter Pump Station as a supplement to water from the then depleted ACT water storages. Water from the Murrumbidgee River has to be pumped from the historic Cotter Pump Station, to the Mount Stromlo Water Treatment Plant to be treated and supplied to the ACT and Queanbeyan.
The Murrumbidgee River is one of Australia's major rivers and many communities use it as their source of water. For decades, major towns upstream and downstream of Canberra, such as Cooma and Wagga Wagga, have been drawing water from the Murrumbidgee River, treating it and safely using it for drinking water supply.
Click here to see our water supply map