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.
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
