The proposal to raise the Warragamba Dam wall will be discussed at the annual meeting of the World Heritage Committee in Bahrain later this month.
Former Blue Mountains MP and Environment Minister Bob Debus, and Harry Burkitt from the Colong Foundation for Wilderness will travel to Bahrain in the hope the governing body for world heritage will stop the proposal.
“We will spend the best part of a week lobbying delegates and putting our case as to why it shouldn’t go ahead,” Mr Burkitt said.
The two are signatories to a letter which also has the backing of former Greens leader Bob Brown, and Joan Domicelj, the principal author of the nomination that saw the Blue Mountains granted World Heritage status. The governing body can add sites to the World Heritage List, and can also revoke a listing or place properties on the list of world heritage in danger.
The proposed increased height of 14 metres would flood up to 1000 hectares of world heritage property and 65 kilometres of wilderness rivers and streams, the Colong Foundation said.
“If the inundation proposal were to proceed the values and integrity of the Greater Blue Mountains World Heritage Area, Blue Mountains national park, declared wilderness, a declared wild river, national heritage and the special catchment area would be significantly degraded,” Mr Debus wrote in the letter.
Australian National University associate professor Jamie Pittock, an environment and floodplain policy expert, said alternatives to raising the dam should be fully considered.
The proposal was raised in June 2016 by then Premier Mike Baird as flood mitigation in the Hawkesbury-Nepean Valley. Western Sydney Minister Stuart Ayres said raising the wall was “a critical part of the NSW government strategy to reduce flood risk and build community resilience for the 130,000 people living in the Hawkesbury-Nepean Valley.
“This strategy is about protecting the lives and property of people who live in the valley, it’s not about facilitating inappropriate development,” he said.