The Blue Mountains World Heritage Area is under threat if the state government’s plans to raise the Warragamba Dam wall proceed, environmentalists warn.
"Raising the dam will destroy unique environments within the Blue Mountains World Heritage Area, including the pristine Kowmung River wilderness,” said Harry Burkitt from the Colong Foundation.
"The Kowmung River is one of only six declared wild rivers in NSW, and it will be permanently scarred from inundation if the dam raising goes ahead.”
Ecologist and former Blue Mountains resident Roger Lembit said the rare Camden White Gum, a unique species of eucalpyt, which is primarily found in the proposed upstream inundation area, would be lost.
“You can’t put them back. The conditions are not the same and the soil changes. Extra sediments change the soil chemistry and invertebrates in the soil are affected,” Mr Lembit said.
Animals would also be affected.
“Platypus in the area and wombats that live on the flood plain are particularly at risk,” Mr Lembit said.
The opportunity for weeds to be introduced and replace native plant communities, was also problematic, he said.
“The proposal being pursued will impact on world heritage area values,” Mr Lembit said.
In June 2016, then Premier Mike Baird said the wall would be raised by 14 metres, as flood mitigation in the Hawkesbury-Nepean Valley.
It "will offer significant extra protection for townships downstream, including Windsor, Richmond and parts of Penrith," Mr Baird told Fairfax Media at the time.
Construction, at an estimated cost of about $690 million, was expected to be complete within three years after a business case is signed off in 2020, subject to planning approvals.
Raising the dam wall is meant to reduce the impact of flooding thanks to a higher capacity to store water before the dam spills, however, it will not stop flooding completely.
There hasn’t been a significant flood event since 1990, but the dam did spill in 2015.
Mr Burkitt said the proposal was unnecessary, and other options should be considered.
"Constructing flood levies, pre-releasing dam water before floods, and not building new housing developments on floodplains are alternative measures that can be implemented at far less cost, while not destroying parts the most protected natural landscape in Australia," he said.
The Colong Foundation has started a campaign against the proposal. Visit www.colongwilderness.org.au for more information.
