The government warned homes on this floodplain would ‘put lives at risk’. Then, it approved 960 of them

The NSW government has green-lit almost 1000 new homes for a flood-prone north-western Sydney suburb two years after Planning Minister Paul Scully warned development could put lives at risk.

The proposed development at Marsden Park North, comprising 960 homes and an employment hub, is in the Hawkesbury-Nepean Valley, considered by the state government to have Australia’s highest unmitigated flood risk exposure.

Blacktown Council has also warned there are critical gaps in funding for the precinct, including “unresolved transport and evacuation infrastructure”.

The decision to push ahead comes as the state struggles with an acute housing shortage. Despite widespread reform of rezoning laws, the number of homes being approved and completed remains below the level to meet demand.

Developer Leamac Property Group first proposed the Marsden Park North precinct more than a decade ago, with plans to build 6000 homes for an estimated population of nearly 20,000 people. The proposal was rejected after flood evacuation modelling found it would have almost doubled the average annual number of people at risk of flood impacts in the catchment by 2041.

A statement released by Scully and Western Sydney Minister Prue Car in October 2023 announcing the proposal’s refusal promised “no more building on high-risk flood plains”.

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

“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.”

Two years later, public exhibition of a scaled-back version of the rezoning – with 960 homes and 260 hectares of industrial land for almost 3900 new jobs – finished on Friday.

The flood evacuation modelling scenarios completed in 2023 found that, even without any further rezoning, there would be an increase in the risk to life from already approved development in the Hawkesbury-Nepean Valley.

In July 2022, flooding in the valley peaked at 13.93 metres – the highest since 1978, although well short of the area’s worst recorded flood (19.6 metres in 1867). Insurers began limiting policies for home owners on the floodplain after the 2022 disaster.

The new development will put homes at the one-in-100 Probable Maximum Flood (PMF) level, with an additional three-metre buffer to allow for climate change — functionally building the homes in areas with a one-in-500 chance of flooding. Hemmed in by Eastern and Southern creeks, most will be built in an area generally safe from inundation, although mapping shows large parts of the precinct would be underwater if the largest conceivable flood hit.

Developers have contested the use of the PMF level in planning decisions because of the minuscule probability of the event, considered between a one-in-10,000 chance to one-in-a million chance.

Further development in flood-prone areas creates risks for upstream residents trying to evacuate, including from areas such as Windsor, due to increased congestion on arterial roadways.

A Blacktown City Council spokesman said it was “generally supportive” of the proposal, and had identified using the area for employment as appropriate to its flood risk.

But the council has identified “critical gaps” in funding for the transport and evacuation infrastructure needed to enable building at the proposed flood planning level. The means of funding repairs to community spaces projected to be damaged by flooding was also unclear.

Scully said the updated proposal aimed to establish land as an employment hub above the new flood planning level, reducing the risk to community safety by building on less flood-prone land and introducing more stringent measures to help evacuations.

“This proposal has been guided by flood modelling and expert advice and is consistent with the recommendations of the 2023 Flood Advisory Panels,” he said.

Declining to speak about specific developments, an Insurance Council of Australia spokeswoman said: “There are already more than 240,000 homes in Australia that face a severe to extreme risk of flooding – we should not be adding to this.”

Leamac founding partner Alexander Leaver declined to comment.

Leamac is a client of Iemma Patterson Premier Advisory, a lobbying firm co-founded by former Labor premier Morris Iemma. Emails released by parliament reveal a push from Iemma and Leamac to ensure a version of the development was successful, including Leamac emailing the premier directly with frustrations about the sluggish process.

Minutes from a meeting of Minns, staff and bureaucrats in June show Leamac noted the department’s “lack of support for a residential development … due to the flood risk”. The developer sought Minns’ “continued support” to ensure the department made quick progress on the proposal.

A Minns spokeswoman said the plans managed risk in line with the 2022 Flood Inquiry’s recommendations.

A department spokeswoman said it improved the 2018 draft rezoning proposal in close consultation with other agencies and Blacktown council, taking flooding events between 2020 and 2022 “into strong consideration”.

Greens’ planning spokesperson Sue Higginson questioned Iemma’s influence in progressing the plan.

“The Minns-Labor government came to power with a clearly stated vision that Western Sydney could not be exploited for development any more. It’s now clear for all to see the crumbling of that conviction when faced with the property developer lobby,” she said.

Responding to questions, Iemma rejected Higginson’s accusation as “factually wrong” and “ignorant of the origins of [the proposal], its status and the actual process being undertaken”.

He noted Marsden Park North had been deemed crucial for future housing and employment needs well before the Minns government was elected.

“[The proposal] is an attempt to end years of paralysis that have stalled the precinct and denied residents of Western Sydney new job opportunities closer to home,” he said. The decision was consistent with the establishment of Western Sydney Airport and Mamre Road industrial hub.

He denied discussing Marsden Park North at meetings with Minns in early 2024. It was Leamac’s decision to engage the premier, rather than the planning minister, Iemma said, noting he did not attend the June meeting.

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