Safety concerns surrounding Warragamba Dam may call for raising its walls

By CHRISTINE LAI

Rising safety concerns over Warragamba Dam may warrant a call to raise the reservoir, with engineering issues of the dam walls potentially requiring remedial work.

The heritage-listed dam located in the outer South Western Sydney area has been subject to controversy over the past decade. Plans by former governments to raise the dam have been strongly opposed by local community groups who have raised serious environmental concerns with plans for the reservoir’s walls to be raised.

According to The Guardian, department officials spoke to ministers in April discussing potential plans for the walls of Warragamba Dam to be raised for “safety reasons”. However, government officials declined to detail the nature of the safety concerns and confirm whether raising the wall would be necessary.

On Tuesday 16th May, NSW Premier Chris Minns stated at a media conference that parliamentary ministers had been briefed on the need for possible repairs.

“There are geotechnical risks associated with the dam wall which means that Water NSW and the Board of Water NSW may have to take action in relation to remediating the structure from an engineering point of view,” Mr Minns said.

“I can confirm I’ve had briefings from engineers at Water NSW about the next steps and we’ll have more to say in the coming days”, he added.

Built in 1960, Warragamba Dam is Sydney’s largest water supply dam and currently stores about 80 per cent of the available water supply for Sydney.

Warragamba Dam declared critical state significant infrastructure project

Last year, the NSW coalition proposed raising Warragamba Dam’s wall, with former premier Dominic Perrottet declaring a critical state significant infrastructure project and committing to raising the wall by 14 metres despite the project lacking environmental approval or funding.

Last year, Perrottet’s government explained their plans to raise the wall was in response to mitigate flood risk in the Hawkesbury-Nepean region. However, Labor’s opposition to raising the Dam affirmed their pre-election promise to scrap plans and pursue alternative mitigation measures.

As reported by the Hills to Hawkesbury, Minister for Water Rose Jackson declared that raising Warragamba Dam would not “guarantee” that communities in Western Sydney would be “safe from flood events.”

Jackson spoke about heritage and environmental concerns attached to plans to raise the Dam, adding that the government were aware that raising the wall would flood the Blue Mountains World Heritage Area, “inundating 1,200 Aboriginal sites and artefacts, destroying habitat for critically endangered species and risk Blue Mountains’ World Heritage listing”.

“The Government’s position is clear, we have always opposed the raising of the Warragamba dam wall,” Water Minister Rose Jackson said.

Opposition to raise the wall linked to heritage and environmental concerns

Several community groups have voiced their opposition to raising Warragamba Dam, with some campaigning to protect the heritage site and other threatened species and communities.

The Blue Mountains Conservation Society have worked alongside Wilderness Australia (formerly the Colong Foundation for Wilderness) for their ‘GIVE A DAM’ campaign where they state that raising the wall would “destroy 65 kilometres of wilderness rivers and inundate 4,700 hectares of the world heritage listed Blue Mountains National Park”.

The GIVE A DAM campaign is described by the groups as a grassroots community campaign created to stop the destruction of the Blue Mountains national park and the over development in western Sydney from the raising of Warragamba Dam wall.

The parliamentary budget office (PBO) estimated a reduction in expenses of $3.9 million in 2022-23 if plans to raise Warragamba Dam were scrapped. Infrastructure NSW (INSW) also advised that the proposed Warragamba Dam raising has an estimated cost of construction of $1.95 billion.

Biodiversity offset costs would need to be paid to compensate for the environmental impacts of the development.

Raising the wall of the Dam would incur costs of $1 billion. Safety issues over the walls of Warragamba and geotechnical issues remain a concern, raising likely repairs for the reservoir.