Infrastructure Australia cannot evaluate dam wall raising proposal until environmental study complete

Thirty years after raising the Warragamba Dam wall to protect homes in flood-prone Western Sydney was first proposed, the federal government is waiting on environmental assessments to evaluate the project.

Thirty years after the idea of raising the Warragamba Dam wall to protect homes in flood-prone Western Sydney was first proposed, the federal government is still waiting on environmental assessments to evaluate the project.

The NSW Government is seeking a 50-50 funding split with the Commonwealth to raise the dam wall by 14 metres, and in January 2022 submitted an early business case to Infrastructure Australia seeking support.

But the information supplied was not sufficient for the federal agency to evaluate the potential cost benefit of the build.

An Infrastructure Australia spokesman has confirmed the agency received an “early version of the business case” for the project from the NSW government in January.

“However we advised that further information and analysis was required before we could proceed with an evaluation,” the spokesman said.

Warragamba Dam spilling flood waters over its wall in March 2022.

“Infrastructure Australia is aware an Environmental Impact Statement (EIS) is underway and expects to receive the Warragamba Dam business case when the EIS is finalised and (Infrastructure NSW) is ready to progress the proposal.”

The Daily Telegraph can reveal the federal government is eager to receive the additional information required from NSW, as the fourth flood in the Hawkesbury and Nepean area in 18 months reignites calls to raise the dam wall.

Flooding and heavy rains caused a sink hole to open and destroy a house on Edwards Rd, Richmond Lowlands. Picture: Damian Shaw

Natural Disaster and Emergency Management Minister Murray Watt said the government was “keen” to better understand the project once Infrastructure Australia had received the necessary information.

It is understood WaterNSW is currently reviewing and responding to the more than 3,000 submissions it received from the public when the EIS for the dam project was published for feedback last year.

Once this is completed it is expected the study will be provided to Infrastructure Australia, which will then evaluate the project.

Debate about raising the dam wall has been ongoing for almost three decades, with a 1995 proposal initially suggesting the height by lifted by 23 metres.

Warragamba dam 50 years

But the then-Carr state government instead decided to manage flood risk in Western Sydney by upgrading roads to make evacuation easier as well as making the dam safer by building a spillway to release excess water.

In 2017 the NSW government released a report which recommended raising the dam wall by 14 metres as the “best option to reduce the risks to life, property and community assets posed by floodwaters”.

This would cost an estimated $1.6 billion.

Prime Minister Anthony Albanese on Tuesday said he was primarily focused on the immediate recovery from this month’s flooding event, and was not yet focused on a longer term mitigation option.

“Proposals will go through, environmental processes will go through, business cases, that will occur,” he said.

“But what we’re dealing with at the moment is the immediate (recovery) concerns.”