Focus on prevention to reduce risk to life during floods in the Hawkesbury-Nepean Valley

The Minns Labor Government is delivering on its election commitment to no longer develop housing on high-risk flood plains in Western Sydney.

The Government is today announcing it has rezoned parts of the North-West Growth corridor to ensure NSW does not construct new homes in high-risk areas.

The Government is also releasing the Flood Evacuation Modelling report for the Hawkesbury-Nepean Valley, which informed the rezoning decisions.

No more building on high-risk flood plains

We cannot continue to develop and build new residential towns in high-risk areas, and risk putting more people in harm’s way.

Following a rigorous assessment process and review of expert advice on flooding, it has been determined the proposed rezoning and draft plans for Marsden Park North precinct and Riverstone Town Centre will not proceed.

The plans for the West Schofields precinct will partially proceed, subject to strict conditions.

The three projects fall within the Hawkesbury-Nepean Valley floodplain and were put on hold in 2020 until further flood risk investigations and evacuation modelling were completed.

It means that, in line with the NSW Government’s election commitment, and in taking a risk-based approach to planning decisions on dangerous flood plains, of the approximately 12,700 new homes previously proposed – but not approved – under the three rezonings, only up to 2,300 will now proceed.

The NSW Government will continue to work closely with councils and other stakeholders to explore suitable land-use options.

Work is also underway to understand where additional housing can be accommodated to mitigate the impacts of these decisions on the housing pipeline.

Flood Evacuation Modelling report for the Hawkesbury-Nepean Valley

The land-use planning decisions follow the release of Flood Evacuation Modelling report for the Hawkesbury-Nepean Valley.

The modelling was undertaken to help make better decisions on emergency evacuations, land use planning and road upgrades in one of Australia’s most dangerous flood risk areas.

The former NSW government commissioned an independent expert inquiry led by Mary O’Kane and Mick Fuller into the preparation for, causes of, response to and recovery from the 2022 catastrophic flood event across the state of NSW.


Key recommendations in the report included revised and updated flood modelling and disaster adaption plans to help resolve rezoning decisions.

This updated modelling has been instrumental in the NSW Government’s consideration of the three planning proposals in Sydney’s North-West Growth Area.

The Hawkesbury-Nepean Valley covers over 500km2 of floodplain in Western Sydney, stretching from Wallacia to Brooklyn and Wisemans Ferry.

It includes land in Hawkesbury, Hills, Blacktown, Penrith, Central Coast, Wollondilly, Liverpool and Hornsby Local Government Areas with more than 140,000 people living or working in the floodplain.

The valley is often compared to a bathtub – one with five ‘taps’ flowing in and only one drain. Between 2020 and 2022, the area flooded six times with some of the largest floods seen in decades.

Sadly, this area has suffered even bigger floods in the past, and the Government must consider the risk of similar floods in the future.

The extreme depth of floods in the valley means that large numbers of people often need to evacuate at short notice before roads out are cut off. It is not possible to shelter in place in these areas.

Adding to the complexity, thousands of vehicles need to evacuate using roads and intersections that were not designed for those levels of traffic.

This technical Flood Evacuation Modelling report for the Hawkesbury-Nepean Valley will be used to reduce the risk to life by informing better planned evacuation routes for flood events, assesses potential road infrastructure options and inform decisions on potential future developments.

While improvements can be made, the flood challenges of the Hawkesbury-Nepean Valley are not ones that communities can build their way out of.

The report makes clear that the number of people who will be unable to evacuate increases significantly with potential future development and climate change.

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Recognising that decisions to limit new homes on the flood plain could raise concerns for small local landowners, the Government has appointed strategic planning expert Professor Roberta Ryan to provide independent community liaison support to help affected landowners them understand and navigate the issues.

Professor Ryan has previously assisted communities in the Western Sydney Aerotropolis and Orchard Hills on land-use planning matters.

The Flood Evacuation Modelling report can be found here and for more information about flooding in the Hawkesbury-Nepean Valley, visit

A new focus on disaster preparedness

What is clear, is NSW’s ability to prevent and prepare for disasters has been hampered by ineffective funding, with 97 per cent of all disaster funding spent after an event and only three per cent spent on prevention and preparedness.

It’s part of why the NSW Reconstruction Authority was established in December 2022 with the expanded responsibilities to include adaption, mitigation and preparedness for natural disasters.

As part of that, an historic $121 million has been invested in the last Budget to properly resource the NSW Reconstruction Authority and allow the authority to support communities across the state better prepare for natural disasters including bushfires, floods and storms.

The authority is working on a State Disaster Mitigation Plan and new regional Disaster Adaptation Plan to reduce the impact of floods in the Valley and this tool will also be used to better understand the risks.

Today’s announcement is a key example of the preventative work that will be prioritised to reduce the impacts of natural disasters in the state.

Minister for Western Sydney, Deputy Premier Prue Car said:

“Western Sydney residents have borne the brunt of recent disasters including the pandemic and floods in the Hawkesbury Nepean Valley.

“By stopping unsafe development in dangerous areas on flood plains, and with our Government’s work to reduce the risk of disasters before they happen, we’re making sure communities across Western Sydney, in areas including Penrith, Blacktown and Riverstone, are finally supported and better protected.

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“When we consider new housing areas, we will look at both the potential for those homes to be inundated in floods, as well as the impact more homes will have on the ability of both new and existing residents to evacuate in emergencies.

“We know we can’t stop natural disasters from occurring, but we are committed to doing more to prepare for and prevent the worst of their impacts.”

“This new tool will not only help us better plan for evacuations but it will also make our amazing emergency service workers safer by reducing the risks they face when responding to floods in the valley.”

Minister for Planning and Public Spaces Paul Scully said:

“We’ve all seen the devastation caused by floods in the Hawkesbury-Nepean Valley – with homes and businesses damaged or destroyed. We also know these communities will only face more and worse flood risks if things stay the same.

“There’s no simple solution but we are working on a suite of measures which includes this tool to help NSW better prepare for disasters.

“These are hard and complex policy problems – we need to deliver new housing, but it needs to be done safely.

“New developments could impact the ability of both new and existing residents to evacuate safely during emergencies, which puts more lives at risk.

“I’d rather a disappointed landowner confront me over a decision we’ve made to keep them safe, rather than console them when they’ve lost a loved one because of floods.

“We’ve been clear that we will put an end to unsuitable development on dangerous flood plains which puts lives at risk and destroys livelihoods – this model gives us the technical data needed to make those informed decisions and balance competing priorities.”