Boosting environmental flows for river health

3 March 2008

To contribute to the health of the Hawkesbury Nepean River, Premier Morris Iemma announced today that environmental flows from Sydney�s dams would be restored to pre-drought levels, beginning on 4 March, 2008, and that flows would commence from Avon Dam.

The Premier said that an improvement in dam levels and the forecast of further rain meant the Government could provide much needed assistance to the Hawkesbury Nepean river system. The restoration of the flows and the new environmental flow from Avon Dam will result in an extra 40 million litres of water being released each day, which is equivalent to the water in 40 olympic-sized swimming pools.

The Government planned to review the environmental flows when dam levels reached the 65-to-70 per cent level, taking into consideration the forecast for sustained rainfall. Those conditions have enabled the restoration of the flows, which will help the river environment.

These restored water releases and the new environmental flow release from Avon Dam represent less than three per cent of the total water we use each day, but they are important for maintaining river health.

Environmental flows from the dams into the river were cut in half in June 2005 when Level 3 water restrictions were introduced.

The Minister for Water, Nathan Rees, and the Minister for Environment and Climate Change, Verity Firth, joined the Premier at the announcement at Warragamba Dam.

Minister Rees said the dam had not only seen a rise in water level, but also a decrease in the concentration of the blue-green algal bloom in Lake Burragorang around the dam wall. Although some algae still persists in the very upper reaches of the dam where the water is warmer, the algae concentration towards the dam wall has been significantly reduced.

It was also announced that environmental flows would be released for the first time from Avon Dam in the Southern Highlands, which would commence later this week. The Government has invested $9.6 million in new infrastructure at Avon Dam to enable the release of environmental flows. The infrastructure will allow the release of the low flows that come into the dam, and provide for flows of a more natural temperature.

This is of considerable environmental significance because low flows are important for river health. The new Avon Dam environmental flows will improve water quality downstream and significantly improve habitat conditions for native flora and fauna. In addition, they will help with fish passage and should restore the river to a more natural condition. Improved river flows are also important for agricultural industries that rely on a healthy river environment.

The increase in environmental flows has been welcomed by the Chief Executive Officer of Greening Australia, Dr David Butcher. He said this organisation had asked the Government to consider maintaining water restrictions in order to increase environmental flows to the Hawkesbury Nepean River. They saw the restoration of the flows as the critical first step to boosting the health of the river system.