The NSW government's $1 billion-plus proposal to raise the wall of Warragamba Dam has been declared critical state infrastructure, fast tracking the project, however the move has attracted fierce opposition.
Premier Dominic Perrottet on Wednesday announced he would pursue raising the wall as NSW faces widespread flooding, with a month's worth of rain predicted to fall on saturated catchments in coming days.
"Today is a landmark day ... for a project that has been talked about for decades," he told reporters.
The declaration of the dam wall raising as Critical State Significant Infrastructure exempts the development from some aspects of environmental and planning laws.
The premier said he did not want the vital infrastructure bogged down in red tape, saying "we need to prepare, we need to invest".
The declaration attracted criticism from Labor and independent MPs, who accused the government of stripping the community of its voice over the project, and putting the area's World Heritage listing at risk.
Environmental advocates went further, calling the step "drastic" and likening it ecological and cultural vandalism.
"It is all about saving lives and protecting property," Mr Perrottet said, adding the project was necessary to help protect western Sydney from floods.
An independent flood inquiry report had determined the best way to protect western Sydney communities downstream was to raise the wall, Mr Perrottet said.
In the case of another major flooding event in the Hawkesbury-Nepean area, raising the dam wall would reduce properties affected from 15,000 to 5000, and reduce the number of evacuations from 90,000 to 14,000, the premier said.
Water Minister Kevin Anderson said the cost of damages would also be reduced by up to $8 billion if the wall was raised.
The government's decision to classify the project as state significant makes it immune from legal challenges and was against the interests of the community, Nature Conservation Council CEO Jacqui Mumford said.
"This project has been rejected by countless organisations, ecologists, archaeologists, hydrologists and traditional owners," Ms Mumford said.
"The only group pushing for this is the developer lobby.
"This looks like a cynical manoeuvre to sweep aside community opposition to this monumental act of ecologically and cultural vandalism."
The project put the Blue Mountains World Heritage listing at risk, and would not prevent flooding in the Hawkesbury-Nepean, as nearly half of floodwaters in the area came from catchments not upstream from the dam, Labor's Penny Sharpe said.
Any new project would take another eight years to complete, and despite 12 years in power, the government had failed to made any progress on raising the dam wall, she added.
Labor has committed $225 million for a western Sydney flood resilience plan for projects including evacuation roads, levees and critical communications infrastructure to bolster flood prevention and evacuation infrastructure.
Independent MP Justin Field said the declaration by the premier was a cynical political move, made ahead of what will be a tight state election.
Multiple assessments had raised serious questions over the benefits of raising the wall, at both the state and federal level, he said.
"This decision strips the rights of the community to challenge a future decision in the courts and that is hugely concerning," Mr Field said.
"That's a flawed process."
WaterNSW will respond to issues raised in submissions on the project before a comprehensive assessment was performed in line with planning laws.
