The NSW government should consider alternatives to raising the Warragamba Dam wall, focusing on improving evacuation routes and protecting more people at risk on the floodplain, a parliamentary committee has recommended.
An inquiry was established in 2019 to consider the government's proposal to raise the Warragamba Dam wall by up to 17 metres.
The upper house committee focused on the adequacy of the environmental impact assessment process to date, any potential impacts on world and Indigenous cultural heritage, and the ecological values of the Blue Mountains National Park.
In an interim report published on Tuesday, the committee recommended the dam wall should not be raised without the prior and informed consent of Aboriginal representatives and without assurance that heritage areas will be protected.
Committee chair, independent MP Justin Field, said the March flood in the Hawkesbury Nepean showed the well-known flood risks in the valley as well as the "limitations" of the current proposal.
"There is strong support from a broad cross section of stakeholders for more consideration of alternatives to the dam wall raising that can minimise upstream impacts to Aboriginal cultural heritage, the world heritage area and the environment while maximising flood risk mitigation for downstream residents and businesses," Mr Field said.
The long-awaited environmental impact statement was published last week and is around 4000 pages long.
"When this inquiry was established in June 2019, it was understood that the EIS was close to completion at that time," Mr Field said.
"However, the final EIS was not released for public exhibition until 29 September 2021."
The committee will address the statement in its final report.