In a 10-2 vote at the January 29 council meeting – two Liberal councillors, Cr Brendan Christie and Cr Kevin Schreiber voted against it – council stated it’s opposition to the dam raising.

“I do not accept it is for flood mitigation,” Mayor Mark Greenhill told the meeting, adding it was about “clearing up land for development in the flood plain”.

“The proposal to raise the Warragamba Dam wall ... is said to be on the basis it is the most effective option to reduce the risks to life and property posed by floodwaters. Yet, expert advice seems to suggest the opposite,” Cr Greenhill said later in a statement.

“The proposal will destroy world heritage listed wilderness on Sydney’s doorstep and desecrate Indigenous culture,” he added.

The Water NSW Amendment (Warragamba Dam) Bill 2018, passed on October 26 last year. The Bill has the effect of amending the National Parks and Wildlife Act 1974 to allow the temporary flooding of the park.

Council is concerned about the the inundation of significant areas of the catchment upstream of the dam and the impact on biodiversity, with species such as the Regent Honeyeater threatened. Council has previously expressed concerns about the proposal’s impact on Indigenous cultural sites.

Both Greens councillors, Cr Brent Hoare and Cr Kerry Brown also expressed concerns about the move.

Cr Hoare said the dam would not stop floods from happening. And Cr Brown said the river systems were the nation’s lifeblood and “we keep interfering with this ancient endangered system”.