Blue Mountains Council has blocked a plan to display WaterNSW "propaganda" about the Warragamba Dam wall

"For us to be displaying their propaganda is inconsistent with the stance we have taken and I don't believe we should do it," Mayor Mark Greenhill told the council at their meeting on June 29.

"We are absolutely opposed to it and will do nothing to help them and everything to stop them."

WaterNSW asked to display at Katoomba Library some 27 pages of the Environmental Impact Statement about the dam raising proposal, but it was not the full EIS public information process, council was told.

The dam wall raising proposal was announced by then premier Mike Baird in 2016 as flood mitigation in the Hawkesbury-Nepean Valley. It involves raising the wall by at least 14 metres. Council, UNESCO, Indigenous and numerous environmental groups have raised concerns and insurance groups have withdrawn support.

In a mayoral minute recommending refusing the Water NSW request council said it "amounts to a flooding to part of the Blue Mountains World Heritage Area, destruction of culturally significant sites, submersion of endangered plant and animal species, a threat to world heritage listing, in turn threatening jobs". The mayor said it promotes an "inconsistent position [and] threatens to confuse the community as to where the council stands [by] use [of] council facilities".

A report in The Sydney Morning Herald on Monday stated WaterNSW plans to have a "time-out room" for "emotional" members of the public with plans to hire security guards and request police attend the public consultation sessions about the dam. Gundungurra traditional owner Kazan Brown has called it "overkill" and Give a Dam campaigner Harry Burkitt from the Colong Foundation said it was "the latest obscenity in this abusive process".

Ms Brown told the Gazette: "I did call it overkill, I also find it offensive intimidating, and demeaning. I think many people will not ask questions or voice opposition to the project in fear of being removed, or police intervening. I feel like these actions will silence our voices. Especially those from the Indigenous community. I think a 'time out' room is for children, not adults."

Mr Burkitt added: "The elaborate planning and heavy-handed security is just the latest obscenity in this abusive process. I guarantee you no one will feel safer after being locked in a room with a bunch of heavy-handed security guards.

"Instead of wasting taxpayers money on manhandling distressed Traditional Owners and environmentalists, WaterNSW should follow the federal environment agency's advice and conduct a proper koala survey in the World Heritage site they plan on trashing."

But when queried a WaterNSW spokesperson denied they had hired security firms for consultation sessions. They are finalising the Environmental Impact Statement (EIS).

"When finalised, the EIS will be publicly exhibited and all interested parties and stakeholders will be encouraged to review and provide feedback," the spokesperson said.

"Dates and locations for the public exhibition of the EIS and community information sessions will take location, capacity, accessibility and ability to comply with COVID-19 safety into account, and will not be finalised until dates for exhibition have been confirmed. WaterNSW has not hired security firms for these consultation sessions.

"Importantly, the final decision on the proposal to raise the dam wall for flood mitigation will only be made after all environmental, cultural, financial and planning assessments are complete."

The UNESCO committee has stated that raising Warragamba Dam's wall and intermittently flooding large areas of the Greater Blue Mountains World Heritage Area would "likely impact on its outstanding universal value". UNESCO has also placed a caveat on the dam's approval, requiring Australia submits the EIS for review to the committee before any final approvals are made.

Blue Mountains MP Trish Doyle said the "inclusion of a 'time out room' in community consultation sessions is absurd and yet another strategy to silence opponents".

"To censor reasonable and necessary opposition to this ludicrous idea shows a total lack of adherence to democratic process."

Ms Doyle said "building on a a flood plain and selling your soul to developers is criminal in itself and the silencing of Indigenous heritage and environmental concerns is unforgiveable. There are many people speaking out vehemently against this proposal - intelligent, informed, expert voices that must not be ignored. Minister Ayres' campaign is fraught with inaccuracies regarding the real impacts and effectiveness of raising the dam wall".

Minister for Western Sydney Stuart Ayres has said the dam raising was one of the most effective ways to reduce the amount of water in the Hawkesbury-Nepean Valley communities.

"Raising the wall has nothing to do with allowing more development in high risk areas," Mr Ayres told the Gazette.

"There are over 5,000 properties that are already in high risk locations that need to be provided with improved protections. Raising the dam wall also substantially improves the performance of flood evacuation routes and flood resilience across the community. Any suggestion that raising the dam is about allowing more development in areas that are currently prohibited is just plain wrong."

During the council vote, Cr Kerry Brown said while she will always "support public information being made available ... my position is they are not putting up the whole of the EIS ... and of course at some point they will have to exhibit the EIS and people will be able to make submissions".

The council vote to refuse WaterNSW's request was passed. Liberal Crs Brendan Christie and Kevin Schreiber abstained from the vote.