The flood problem, immigration and population growth

Jul 25, 2022
Hawkesbury River in Flood
Image: Flickr / Jim Dean

The management of weather-related emergency situations like floods is the responsibility of the states. But the policies and activities of the Commonwealth government can make big differences to the impacts of floods, either for better or for worse. This is clearly demonstrated via immigration policy and its impact on population growth.

The principal destinations of migrants to Australia are Sydney, Melbourne and south-eastern Queensland. Arriving in these major metropolitan areas, migrants create the stimuli for housing growth at the urban fringes as well as pushing up housing prices. By pushing up prices they provide opportunities for Australians to make capital gains, sell up and move to other parts of Australia in what have become known as ‘sea changer’ and tree changer’ lifestyle movements. In recent decades these movements have modified the demographic landscape of the nation while the age-old expansion of our major cities has continued at their edges.

What are the results of these movements in terms of community vulnerability to floods? Let’s take the case of Sydney.

Sydney’s primary edge-of-metropolis growth foci are in the north-west and south-west, and one of the major areas outside the capital to which people flow from Sydney to live is the lower Hunter Valley where demand for housing is strong. All of these areas have substantial problems in relation to the hazard of flooding, both in terms of inundation (the valleys of the Hawkesbury and Nepean rivers have been much afflicted in recent months) and as regards the physical isolation which can be brought about when flooding occurs. Flood-induced isolation has recently become a serious problem in the lower Hunter. Profound questions are being asked of the way we create new housing supply in areas that can be inundated or isolated when floods strike.

The problems of the Hawkesbury-Nepean in regard to floods are well known. Housing growth there is at historic highs and is proceeding apace. Much of the growth is taking place on floodplains, for example along Eastern and South creeks which enter the Hawkesbury River immediately downstream of Windsor. The Hawkesbury, Blacktown and Hills councils have major plans for residential subdivisions, as does Penrith further up the valley. One state government report estimates that 12,000 new dwellings are slated for construction in the Hawkesbury-Nepean Valley by 2041. Large areas at Marsden Park, Marsden Park North, Riverstone are currently being rapidly transformed from green fields to suburbs.

There is an inevitability here. To the extent that these areas of massive housing development are on floodplains, human vulnerability to floods is being augmented.

In the Hunter, the issue is different: isolation is the major problem. Gillieston Heights, a new dormitory suburb on the edge of Maitland, developed since the turn of the century and now home to well over 4000 people, was recently isolated for nine days by flooding on nearby Wallis and Fishery creeks which are tributaries of the Hunter River. The area had been similarly isolated for five days in 2015. The only road in and out was cut in both events by flooding immediately north and south, low-set stretches of road respectively 900 metres and 500 metres being inundated. Both stretches need building up or bridging well above the current road levels if the problem is to be overcome: arguably, this should have been attended to before Gillieston Heights became a suburb.

Other nearby centres undergoing rapid housing development, Bolwarra and Largs, are also prone to becoming isolated by floods. These places, like others in the vicinity, are under significant growth pressures. One location, Wallalong, has been proposed as a ‘new town’, its current population of more than 1000 people having been slated in recent times to accommodate a further 9000. Wallalong is cut off for kilometres in all directions when floods strike, and avoiding that outcome by building up roads or constructing long bridges would be very expensive. The costs would be far in excess of the developers’ contributions that normally attend investment in major new housing estates.

Major development at Wallalong has been forestalled by a decision of the New South Wales Department of Planning and Environment. But the proposal is still listed by its proponent as a future residential project and the local council (Port Stephens) appears to have maintained its support.

It is obvious that inundation of people’s dwellings by floods is undesirable. Less obvious is the hardship brought about by flood isolation. But when people are cut off in large numbers the consequences are more severe than our planning practices usually recognise. Ambulances cannot gain access, and people with medical problems require expensive and relatively inefficient evacuation to hospital by helicopter or floodboat. Sometimes, the delays that result are life-threatening. In 2015 at Gillieston Heights there were two babies with breathing difficulties and one born premature who needed urgent hospitalisation, a heart attack victim, a man who fell and dislocated a hip and a woman who went into labour and needed hospital attention. The flood of July 2022 produced several similar cases.

People, not able to get to work, can run out of money for essentials. Local stores, if they exist (sometimes the threshold populations needed to support them have yet to be achieved), are denuded of stocks and need resupply by floodboat as do pharmacies. Boredom sets in when normal social life and work activities are suspended, potentially with damaging results such as increased abuse of alcohol or other instances of dangerous or illegal behaviour. And if fire should break out, the consequences are dire if fire appliances cannot gain access to extinguish them.

In 1997, a flood in the US city of Grand Forks (population 50,000) in North Dakota was assailed by a flood on the Red River of the North which overtopped the local levee. A gas pipeline was ruptured by the floodwaters, a spark started a fire in an office building and the flames spread rapidly to others, and the response of the local firefighters was badly curtailed by the flooding in the streets. Eleven buildings, including apartment buildings, were destroyed. Much of the Central Business District burned down, leading to a long, painful and incomplete economic re-building in which a number of businesses failed to survive. Grand Forks’ role as a regional centre was diminished.

At Gillieston Heights two weeks ago the emergency services, in the Australian way staffed largely by volunteers in organisations like the State Emergency Service and the Rural Fire Service, were left to mount the effort to overcome the isolation which can be sheeted back to inappropriate subdivision location or poor planning of roads.

Part of the reason for rapid suburban development in such areas is high immigration. Immigration helps to trigger the internal migration flows that demand housing which, in the absence of suitable sites, tends to be provided on floodplains or in locations that are bound to be cut off from time to time. Before COVID-19, the excess of immigrants over emigrants was adding an average of 1% to Australia’s population annually, a figure averaging roughly 250,000. In all likelihood, immigration at levels like this will become the norm again when the pandemic ends.

Why is this housing situation being allowed to develop? Years ago, the number of people in the lower Hunter whose houses were subject to inundation or isolation in flood times (mostly farmers living on their land) was in the hundreds. Now it is in the thousands. Potentially it will soon become many thousands.

A coalition of business and government, including councils of local government, supports strong growth. But we are handling that growth badly in terms of allowing it to push more and more people into circumstances of vulnerability in the face of a major and predictable threat.

We can do better than this on several levels. Do we really need high immigration, buttressed by strong demands for labour, to foment these problems while TAFE colleges endure funding cuts and universities are forced to reduce their staffs? Are we investing sufficiently in the education and skills of current residents? Must we take the lazy way to build our population using family and skills-based immigration? And must we put ever-larger numbers of our rapidly growing population in houses on floodplains or in places which are certain to be cut off by floods? And lastly, is it ethically reasonable to rely on volunteers to conduct risky resupply and rescue operations in locations which should not have been settled in the first place?

The root of the problem is the fact that we have built substantial populations in inadvisable locations or failed to make the locations appropriate by investing adequately in the roads that connect them to sources of supply. Given the scarcity of land that is suitable for housing near our big cities, and the impossibility of large-scale population growth occurring in regional areas west of the Great Dividing Range, we should consider cutting net immigration to say 50,000-100,000 (perhaps with a higher proportion of the intake being made up of refugees than is currently the case). We should also bolster our skills development locally rather than relying on the easy, lazy method of attracting people who acquired their skills in their homelands.

And most obviously of all we should take more care to avoid mass floodplain development and ensure that isolation resulting from floods is not allowed to be increased.

We have been building our flood problem for decades. Lately, just as it appears that climate change is worsening the problem by intensifying short-term rainfalls, we appear to be building our difficulties at an increased rate. This makes no sense.

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