Water security should be front and centre of population debate

By Leith van Onselen

Last month, Dr Jonathan Sobels – a senior research fellow at the University of South Australia and the author of a key 2010 report prepared for the Department of Immigration entitled Long-term physical implications of net overseas migration: Australia in 2050gave a brilliant incisive interview on ABC’s Radio National that among other things warned that Australia’s water security is being placed at risk from endless mass immigration:

…we are coming up towards physical limitations within our physical, built and natural environments that will lead to compromises in the quality of our life…

Not only are the dams not filling, but the ground water supplies are not filling. The only option you have open to you is water efficiency use and whacking up desal plants. But if your population keeps increasing at the rates we have seen in recent times, you won’t be able to afford putting up billion dollar desal plants, which also have their environmental impacts…

Yesterday, ABC News entered the debate and warned that Australia’s water supplies will be placed under intense pressure as the nation’s population balloons:

Increasing demand for water needs to be addressed.

To grasp how real this prospect is, you only need to look at the population forecasts.

In Sydney, when Warragamba dam is full, the city has about four years worth of water supply.

Double the population, as is forecast in 50 years, and that falls to two years worth of water supply — and that is only when it is full, a scenario that might become a lot less frequent with climate change.

But that is what desalination plants are for, right? Well … only to a point.

In Sydney, most of the 725,000 new dwellings that will need to be built by 2036 to keep pace with population growth will be built in the west, according to the Greater Sydney Commission.

The compass direction changes, but the trend is the same for all coastal capital cities: population growth is moving away from the coast and away from desalination plants.

“Water being non-compressible and quite a heavy substance — it’s quite expensive to transport,” said Mr Lovell.

“Even if you’re looking at Sydney on the coast through to Penrith or from Wonthaggi to the north of Melbourne — you’re looking at 80 to 90 kilometres. That’s really expensive, and it’s a really inefficient way to transport water.”

In Sydney, for instance, infrastructure is only in place to pump desalinated water from the plant in Kurnell to the CBD and eastern suburbs.

Professor Khan said a whole new set of pipelines would need to be built to get desalinated water west of there, where the population growth will be.

“The further you (pump desalinated water) inland, the more you’re working in a direction that is opposite to the way our water supply systems are designed and operate,” he said.

“They pump water from the source — up in the reservoirs, up in the hills — to the coast. And it’s very difficult to actually turn that around.”

It is not impossible for these pipelines to be built to the west, but it will cost a lot of money.

Of course, desalination plants are environmentally destructive and hideously expensive, with costs borne by the incumbent population, as noted by The Conversation:

The desalination plants were expensive to build, consume vast quantities of electricity and are very expensive to run. They remain costly to maintain, even if they do not supply desalinated water. All residents pay higher water rates as a result of their existence.

Indeed, in December, Infrastructure Australia reported that household water bills will double in line with energy bills because of population growth and climate change – hitting more than $2500 a year by 2040:

Modelling in the report forecasts that a typical residential water and sewerage bill “could rise by around $600 in today’s money over the next 10 years”. This would result in average bills increasing from $1226 to $1827 in 2027. By 2040, the modelling shows the average would reach as high as $2553. This would represent more than a doubling in real terms.

“For many families, growth in bills of this scale could cause significant hardship”…

The report says that a failure to factor in urban population growth, ageing infrastructure and climate change impacts on supply would expose consumers to price shock risks. It says the millennium drought “exposed a number of vulnerabilities of the sector, and led to over $11 billion of investment (in today’s dollars) to augment supply through desalination plants”.

However, The ABC reckons it has the solution in hand: water recycling:

Desalinated water costs roughly twice as much to treat as recycled water, according to Mr Lovell. And that’s before you start adding in the costs of a pipeline.

Professor Khan said it would be much easier and cheaper to recycle water from a wastewater treatment plant close to where water is traditionally supplied from, to make use of existing infrastructure.

“I think in the future that’s the way all big cities will go,” he said.

Mr Lovell agreed. “In terms of an overall water supply strategy for a city, it’s absolutely critical for the future. It’ll help to form the backbone of water supplies”…

There are examples around the world where people are already drinking recycled effluent — sewage that is treated to a drinkable standard and then pumped into water storages or directly to consumers’ homes.

They include countries such as Singapore and Namibia, towns in Texas and California, as well as somewhere a lot closer to home.

“The technology is very straight-forward and the risks are almost negligible. The issues are about community acceptance and bringing the community along,” said Sue Murphy, the CEO of the Water Corporation of Western Australia.

Perth’s water management system has been hailed as best practice around the world.

The city is on the same latitude as Cape Town in South Africa, and faces similar climate pressures.

But unlike Cape Town, which earlier this year named a “Day Zero” when water supplies would run out, Perth is forecast to be able to cope with a growing population and increasingly unstable climate.

Perth has two desalination plants that run at full capacity, and since last year has been pumping recycled sewage back into the city’s groundwater.

There is, of course, an even cheaper solution to ameliorating water pressures – one that requires minimal additional investment, nor expensive technical solutions like desalination of recycling of effluent: cutting immigration back to historical levels:

As noted in the 2010 report prepared for the Department of Immigration, entitled Long-term physical implications of net overseas migration: Australia in 2050:

Decreased urban water supply is a significant environmental constraint exacerbated by higher levels of NOM.  Modelling shows the vulnerability of Sydney, Melbourne, Brisbane and Perth to deficits in water supply, on a NOM strategy of 260,000 pa.: a view strongly supported by empirical review of State Government reports…

Only NOM levels of 50,000 pa or less result in Melbourne and Sydney maintaining a small surplus of net surface supply over demand on average out to 2050, assuming current climate conditions persist. Potential options to alleviate water stress at high NOM levels over the longer term may be hard to find.

Clearly, Australia’s mass immigration ‘Big Australia’ policy is a key threat to Australia’s water security. So why exacerabte the problem in the first place, when it can be ameliorated by simply returning Australia’s immigration intake back to the historical average of 70,000 people a year?

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Unconventional Economist
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    • Did you know the average long term rainfall for sydney or melb is 2x that for london or paris.

      • So, what happens to all the rain which falls here, given london and paris are continually wet, damp and overcast
        and have about 5x more people.
        Though i have to admit at least strayans have a daily bath or shower!

      • Eastern Sydney has a wet climate. However Western Sydney (where all the new residents are being dumped) has about 40-50% less rainfall, also much hotter and less tree coverage. The main catchment areas (necessarily at higher altitude) also receive less rainfall.

        This is the general pattern throughout Australia, a thin coastal strip receives most of the rain, by the time you cross the Dividing Range there is very little, and only a couple (one?) of large (permanently flowing) rivers. Most fresh water washes straight back to sea.

      • dan, at risk of starting a global warming temp rise war here, where do you recon the rain gauge for sydney is??

      • WW, Melbourne seems a rainy damp city by the number of rain days, but precipitation levels are quite low. In winter the cold fronts may only bring a couple of millimetres. That being said, the rainfall amounts varies considerably with the west having less and mountain ranges to the east having considerably more. Also south has more compared with the north.
        However, as you have eluded to, the weather is becoming drier which sort of proves the folly of the population ponzi in Melbourne. Why are we cramming more people into a region that will become hotter and drier in the future.

      • Usually when they say “Sydney” they mean Observatory Hill in the CBD. Surrounded on 3 sides by water its a little more humid than most parts of Sydney.

        From the GSC strategic plan:


        Sydney City: 1215mm
        Parramatta: 973 mm
        Badgery’s Creek : 683 mm

        Days over 35 degrees p.a.

        Sydney City: 3 days
        Parramatta: 11 days
        Penrith: 21 days

        Tree cover
        Sydney City: 32%
        Parramatta :17%
        Badgery’s: 16%

        Not hard to see that western Sydney is going to generate above average demand for water, also power for air-conditioning etc. And that’s where all the new inhabitants are going to be put.

      • Well guys good work
        I guess the bottom line is sydney ran out of water about 12 months after it was settled as tank ck became polluted
        and melbourne the same as the yarra yarra falls tidal barrier also became polluted
        Both those water supplies were mandated by the govt of the day to not become polluted, but what happened??
        This time will be the same!

      • Random PunterMEMBER

        Average annual rainfall is only one small part of the equation. You also have to consider how rainfall totals are spread throughout the year, how reliable those totals are, how large/numerous the dams are to capture the runoff, the proportion of runoff that makes it to the dam, the annual effects of evaporation on stored water, and finally the end-user demand.

        It’s entirely feasible for a location with low annual rainfall to be more water secure than somewhere with higher rainfall. In many parts of Australia the annual average has a large seasonal/monsoonal component to it. A series of poor/failed wet seasons might not have much impact on the long-term annual average, but can be devastating to the security of supply. This is precisely the problem currently affecting the residents of Palm Island (near Townsville), annual average rainfall ~1000 mm.

      • Most important factor is the multi-year variability I believe. Most of Australia has El Nino/La Nina cycles and multi year droughts are common. It doesn’t help that Warragamba may have been bursting at the seams for 5 years before the dry kicks in. These dams get perilously close to empty during droughts and storage capacity really should be scaling with population growth. But it isn’t, almost none has been added since last time we came close to running out.

    • Time for some racist jokes about water :-

      Where do you hide your valuables when an Englishman comes to visit? Under the soap.

      How do you tell the age of an Englishman? Count the bathtub rings.

      I would like to dedicate those jokes to Joe Hildebrandt.

  1. truthisfashionable

    I also think it’s time to ‘force’ some productivity increases from our Farmers who are our largest water users and from the dozen or so reports I’ve seen, aren’t very water efficient.

    A rough example is: Every water license should reduce the amount of water by 10% every 2 years.
    So if you buy a 10yr license of 10Kl, the first 2yrs gives you the full 10Kl, then from year 2 to year 4 it’s 9Kl, from yr 4 to yr 6 it’s 8.1Kl and so on.

    • Exactly!!

      Green revolution has been yet another Ponzi scheme – it just shifts the bottleneck caused by population explosion from food shortage to something else while destroying landscapes by massive irrigation.

  2. Melbourne looks the biggest worry to me. Dams haven’t been full since 1996 but population has grown close to 50% since then. Currently at 63% of capacity, a prolonged dry spell could drain them in two years. Population growth and logging around catchments not helpful.

    • Completely agree. Yes, a big desalination plant was built, but population has increased 1 million since the last drought. There has been no discussion of water security during the big Australia debate and when it is mentioned, it is just build more desalination plants.

      I drove through the road between Marysville and Warburton during the Labour Day weekend and was horrified to see that they are logging in the catchments. It is though Melbourne wants to be the next Cape Town.

  3. Sydney’s topography would allow creation of many urban reservoirs, and create water-views! Example is Manly Dam.
    Kuringgai Chase could become a new urban growth area; GSC (Lucy T) take note!

  4. Look at Cape Town as an example.
    It took only 3 years without significant rain to bring it to its knees.
    The big issue is that its doesn’t become an issue until the last minute.
    Water drains fast enough to catch you off guard; slow enough for you not to notice.
    Even at 22% water left, Cape Town have pushed back day zero till the end of the year!
    Thats how complacent people can get