Urban planners and water scientists have urged the New South Wales government to offer to buy back thousands of homes in flood-prone areas of western Sydney, as overdevelopment sets a trajectory for the number of uninsurable houses in the city to surge.
Infrastructure NSW has acknowledged residential property buybacks would be “effective” to mitigate flood risk in the Hawkesbury-Nepean Valley and across western Sydney, but the government agency has said such a scheme would incur “very significant social and economic costs”.
The call for buybacks, from the urban thinktank the Committee for Sydney, followed floods in March that inundated parts of western Sydney after Warragamba Dam spilled over, and wreaked havoc across NSW and south-east Queensland.
By Tuesday, the insurance bill for the floods had risen to $537m, from 35,845 claims, as affected residents continue to lodge damage with their insurers.
The Committee for Sydney’s resilience director, Sam Kernaghan, believes the insurance bill for March’s floods will rise to $2bn and says it will ultimately cost the NSW government too as it foots the bill for emergency services and recovery relief services as insurer of last resort.
The committee has issued a plea for the state’s recovery and rebuilding to seriously consider not “reestablishing homes, farms and businesses in this increasingly hazard prone location”.
“The bill will be enormous… [instead] we have an opportunity to use that money differently to support western Sydney residents and businesses for the long term,” the committee said, calling for the billions to be spent rebuilding to focus on a voluntary home purchasing scheme “that supports residents to move out of the way of the floods”.
“Funded by state government, this scheme would provide a mechanism for residents to sell flood risk properties to the government at market rates,” the committee said, noting a similar scheme put in place after the 2011 Queensland floods that saw Brisbane city council purchase $35m in flood-affected land, with properties transformed into parkland.
Kernaghan believes there is a strong argument to buy back about 5,000 to 7,000 homes in western Sydney – not all of the 55,000 to 77,000 that are estimated to need to evacuate during a one in 100-year flood event.
“Some people have chosen to live there, to take on that risk, and can afford the insurance to do that,” Kernaghan said. “But there are people living with the risk who maybe didn’t know that when they moved there, who can’t afford insurance and can’t get out now, because nobody is willing to buy their home. There needs to be a way out for them.”
The committee is also calling for more thorough mapping of flood plains in Sydney to help long-term planning, as well as transferrable development rights similar to the model used in Norfolk, Virginia – a US city sinking more than 3.5mm a year – and strengthening evacuation routes to help existing communities in the Hawkesbury-Nepean floodplain.
Kernaghan notes the NSW government’s plan to raise the wall of Warragamba Dam could prevent minor flooding, but said more drastic action was needed to address the kind of major flooding seen in March.
“If nothing is done to address this escalating risk from extreme weather and climate change, by 2100 Sydney will have a projected 91,000 “uninsurable” addresses — the most of any city — with over five times as many uninsurable properties in 2100 than in 2019,” he said.
“Regardless of what Sydney decides to do, the question before western Sydney is this: do we really want to continue to put people in the flood plain? Previous governments ignored the science, hoping it would be all right. The result has been tragedy for thousands of people.
“The recent floods should make it clear it is not responsible to put people where they will be exposed to this level of harm ... It’s time for Sydney to look at a long-term plan to reduce the cycle of disaster.”
Dr Ian Wright, a water scientist at Western Sydney University who previously worked as a scientist for Sydney Water studying the Sydney basin flows, also supports the concept of home buybacks.
Wright has been a vocal part of the chorus of water scientists warning of the impact overdevelopment had on the recent floods.
As large swathes of western Sydney that were previously bushland and soil – which absorb water before flooding – had been paved over and roads and hard surfaces built to support new suburbs in recent years, there is increased runoff and flood risk to communities lower down. Residents in western Sydney complained of this issue as their homes, which had seen out previous floods, succumbed to the recent deluge.
Wright said buying back properties “absolutely makes sense”. Flood planning “has always seemed to be about 50 years behind our bushfire planning, and that’s because there’s a more visible and frequent impact”.
“But when it does flood, the risk and damage is enormous,” Wright said.
“There has been a juggernaut of development in western Sydney. We have been building in locations we shouldn’t be building, and we’re still doing it today. It’s absolutely chilling.”
Wright said development in parts of western Sydney was “pushing back on nature and not respecting it as a flood plain”.
“We’re pushing too far into areas where homes might be cheaper but insurance costs will make it prohibitive to live there.
“This is western Sydney, we’ve got a lot of people on big mortgages and insecure employment. People often don’t realise they’ve bought in a flood-prone area until they’ve applied for insurance or a development application.”
The NSW planning minister, Rob Stokes, referred the Guardian’s inquiries to environment minister Matt Kean’s office, which referred it to Infrastructure NSW.
An Infrastructure NSW spokeswoman said the government had considered buybacks to mitigate flood risk, including in its Hawkesbury-Nepean flood strategy released in 2018.
“However, in the Hawkesbury-Nepean Valley, large-scale compulsory acquisition across entire suburbs would be necessary for this to be effective and would have very significant social and economic costs,” she said.