Hawkesbury housing developments dumped due to deadly flood risk

The NSW government will scrap plans for thousands of new homes in the Hawkesbury region after a secret flood evacuation modelling report found a “risk to life”.

Thousands of new homes proposed across Sydney’s northwest will no longer go ahead after a secret state government flood report declared there was a “risk to life” in the “bathtub” of the Hawkesbury area.

In a major blow to an estimated 1030 landholders, homes at Marsden Park North and parts of West Schofields will not be built, while plans for a new Riverstone Town Centre will also be scrapped.

The decision to stop building homes on “high risk flood plains” follows the release under Freedom of Information laws of a 74-page flood evacuation modelling report to The Sunday Telegraph.

Commissioned by the former Coalition government to examine evacuation routes, the report was never made public despite multiple requests for it to be released to end the “limbo” for landholders after development was paused after the catastrophic 2020 floods.

Alfred Attard with his horse Philla's Reason at his property in Marsden Park. Picture: Adam Yip

The report modelled different flood events to determine the “risk to life” – people unable to evacuate within 12 hours due to floodwaters or being trapped on the roads.

It found the number of people unable to evacuate increased significantly if “all potential development was to occur”, with the impact greatly worsened under climate change.

Artists impressions of the now scrapped Marsden Park North rezoning project.

“For example, for a 1 in 500 chance per year flood (similar to the worst flood on

record) the risk to life would increase from an estimated 980 people under committed development to around 23,700 people by 2041,” it said.

In acknowledging some landholders will be “shocked” at the decision, the government has set up a hotline while appointing a planning expert to ­liaise with those affected by the decision.

Western Sydney Minister Prue Car said the decision was necessary to ensure communities on were better protected.

“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,” she said.

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

Ms Car said the report would also help the government “better plan” evacuations while also reducing the risks to emergency service workers responding to floods.

The report described the Hawkesbury-Nepean Valley as having “the highest unmitigated flood risk exposure in Australia” as a result of the “bathtub effect” from having multiple tributaries flowing in and only the Hawkesbury River allowing it to drain out.

“Floodwaters back up and rise rapidly, causing deep and widespread flooding across the flood plain,” it said.

“The effects are much like a bathtub with multiple taps turned on, but only one plug hole to let the water out.

“Floods pose a serious risk to safety in the Hawkesbury-Nepean Valley.”

Planning Minister Paul Scully said the proposed ­development could have impacted the ability of both new and existing residents to evacuate safely.

Affected areas: Marsden Park North (1), West Schofields (2), Riverstone Town Centre (3).

“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,” he said.

The decision to no longer develop housing on high-risk flood plains was an election commitment by the Minns government, which also chose not to proceed with raising of Warragamba Dam wall.

A government source said increasing the height of the wall would not have changed the residential development ban with 45 per cent of floodwaters in the area coming from creeks and rivers rather than upstream from Warragamba.

Part of Sydney’s northwest growth corridor, an estimated 12,700 homes were to have been built in Marsden Park North and West Schofields.

Now just 2300 will proceed.

While the land had been earmarked for a residential rezoning, it had never been ­approved.

However, planning officials conceded some landholders potentially hoping to subdivide or build would be “shocked” by the decision.

A part of West Schofields will still be able to be developed under strict conditions.

The move to ban housing on the flood plain is a significant blow to the Minns government in addressing critical supply issues, with NSW tasked to deliver up to 75,000 houses each year for five years to meet national targets.

While development has been scrapped, the government is still throwing an initial $200 million over the next two years for the Pitt Town Bypass, Garfield Road East at Riverstone and the Richmond Rd – M7 to Townson Rd – ­upgrade.

Land owners like Alfred Attard bought homes with large parcels of land, taking the chance that one day his property couldbe rezoned for development.

Oakville sheds and houses under water on the flooded Hawkesbury river near Windsor. Picture: Jane Dempster/The Australian

The 68-year-old has owned his property north of Marsden Park since 1994, and has lived in uncertainty ever since, hoping hewill be able to sell to developers.

“We are living in limbo, your dream is to pay the price off, work your butt off and if our dreams come through, we could buy another place — but nothing is paying off,” Mr Attard said.

“I think the zoning should change, it should be residential.”

Mr Attard said in previous floods water has not entered his property, and was in favour of raising the Warragamba Dam to mitigatethe risk to his property.

Mr Attard is waiting to be told if he is one of an estimated 1,030 land holders who will now have their dreams of subdividing and developing dashed, with the NSW Government scrapping plans to rezone the area.

“We just want some hope,” he said.

Mr Attard, if told he is impacted by the decision, won’t be forced to leave his existing home, however others may not be so lucky.

Nearby in Garfield Rd West — the main flood evacuation route — one land holder who didn’t wish to be named was living in a caravan with hopes of building a permanent home when the rezoning took place.

His plans are now in tatters and will likely have to remain living in his temporary home, with no new residential buildings allowed to proceed.

LEFT HIGH AND DRY

Landowners such as Alfred Attard bought homes with large parcels of land, taking the chance that one day his property could be rezoned for development.

Alfred Attard with his horse Philla's reason at his property in Marsden Park. Picture: Adam Yip

The 68-year-old has owned his property north of Marsden Park since 1994.

“We are living in limbo,” Mr Attard said. “I think the zoning should change, it should be residential.”

Mr Attard said in previous floods water has not entered his property and was in favour of raising the Warragamba Dam to mitigate the risk to his property.

Mr Attard is waiting to be told if he is one of the land holders affected.

“We just want some hope,” he said.