You can leave water out for wildlife without attracting mosquitoes, if you take a few precautions



Leaving water out for wildlife is important during droughts and bushfires but if it’s not changed regularly it can be a breeding ground for mosquitoes.
Roger Smith/Flickr, CC BY-NC

Cameron Webb, University of Sydney

Australia is in for a long, hot summer. The recent bushfires have been devastating for communities and wildlife. Drought is also impacting many regions.

Understandably, people want to leave water out for thirsty birds and animals.

Health authorities generally warn against collecting and storing water in backyards as one measure to protect against mosquito bites and mosquito-borne diseases caused by, for example, dengue and Ross River viruses.




Read more:
How Australian wildlife spread and suppress Ross River virus


But it’s possible to leave water out for wildlife – and save water for your garden – without supplying a breeding ground for mosquitoes, if you take a few precautions.

For some mozzies, any water will do

Mosquitoes often look for wetlands and ponds to lay their eggs. But sometimes, anything that holds water – a bucket, bird bath, drain or rainwater tank – will do.

When the immature stages of mosquitoes hatch out of those eggs, they wriggle about in the water for a week or so before emerging to fly off in search of blood.

While there are many mosquitoes found in wetlands and bushland areas, Aedes notoscriptus and Culex quinquefasciatus are the mosquitoes most commonly found in our backyards and have been shown to transmit pathogens that cause mosquito-borne disease.

The Australian backyard mosquito (Aedes notoscriptus) is quick to take advantage of water-filled containers around the home.
Cameron Webb (NSW Health Pathology)

In central and north Queensland, mosquitoes such as Aedes aegypti can bring more serious health threats, such as dengue, to some towns.




Read more:
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Mosquitoes can also impact our quality of life through bites as well as the nuisance of simply buzzing about our bedrooms and backyards.

So how can you stop mozzies making a home in your backyard?

Empty water containers once a week

Mosquitoes need access to standing water for about a week or so. Reduce the number of water-filled containers available or how long that water is available to mosquitoes.

Emptying a water-filled container once a week will stop the immature mosquitoes from completing their development and emerging as adults.

If you’re leaving water out for pets or wildlife, use smaller volume containers that will allow for easy emptying once a week. You can tip any remaining water into the garden, as mosquito larvae won’t survive if they’re “stranded” on soil.

For larger or heavier items, such as bird baths, flushing them out once a week with the hose will knock out most of the wrigglers and stop the mosquitoes completing their life cycle.

Make sure garden water doesn’t slosh about

Be careful with self-watering planter boxes. These often have a reservoir of water in their base and, while it may seem like a water-wise idea, these can turn into tiny mozzie hotels!

A simple trick to keep water available to plants, but not mosquitoes, is to fill your potted plant saucers with sand. The sand traps and stores some moisture but there is no water sloshing about for mosquitoes.

If you’re collecting water from showers, baths, or washing machines (commonly known as grey water), use it immediately on the garden, don’t store it outside in buckets or other containers.




Read more:
How drought is affecting water supply in Australia’s capital cities


Gutters, ponds, tanks and pools

Make sure your roof gutters and drains are free of leaves and other debris that will trap water and provide opportunities for mosquitoes.

Ensure rainwater tanks (and other large water-storage containers) are appropriately screened to prevent access by mosquitoes.

Rainwater tanks can be a useful way to conserve water in our cities but they can also be a source of mosquitoes.
Cameron Webb (NSW Health Pathology)

A well maintained swimming pool won’t be a source of mosquitoes. But if it’s turning “green”, through neglect and not intent, it may become a problem. Mosquitoes don’t like the chlorine or salt treatments typically used for swimming pools but when there is a build up of leaves and other detritus, as well as algae, the mosquitoes will move in.




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For backyard ponds, introducing native fish can help keep mosquito numbers down.

But if you want your pond to be a home for frogs, avoid fish as they may eat the tadpoles. Instead, try to encourage other wildlife that may help keep mosquito numbers down by creating habitats for spiders and other predatory insects, reptiles, frogs, birds, and bats.

Avoiding excessive use of insecticides around the backyard will help encourage and protect that wildlife too.

Mozzies can still come

There isn’t much that can be done about those mosquitoes flying in from over the back fences from local bushland or wetland areas.

Mosquitoes are generally most active at dusk and dawn so keep that in mind when planning time outdoors. But when mosquito populations are peaking, they’ll be active almost all day long.

Applying an insect repellent can be a safe and effective way to stop those bites.




Read more:
The best (and worst) ways to beat mosquito bites


Covering up with long pants, long-sleeved shirt and shoes will provide a physical barrier to mosquitoes. If you’re spending a lot of time outdoors, perhaps even consider treating your clothing with insecticide to add that extra little bit of protection.

Make sure insect screens are installed, and in good condition, on windows and doors. Mosquitoes outdoors can be bad; you don’t want them inside as well.The Conversation

Cameron Webb, Clinical Lecturer and Principal Hospital Scientist, University of Sydney

This article is republished from The Conversation under a Creative Commons license. Read the original article.

The sweet relief of rain after bushfires threatens disaster for our rivers



After heavy rainfall, debris could wash into our waterways and threaten fish, water bugs, and other aquatic species.
Jarod Lyon, Author provided

Paul McInerney, CSIRO; Gavin Rees, CSIRO, and Klaus Joehnk, CSIRO

When heavy rainfall eventually extinguishes the flames ravaging south-east Australia, another ecological threat will arise. Sediment, ash and debris washing into our waterways, particularly in the Murray-Darling Basin, may decimate aquatic life.

We’ve seen this before. Following 2003 bushfires in Victoria’s alpine region, water filled with sediment and debris (known as sediment slugs) flowed into rivers and lakes, heavily reducing fish populations. We’ll likely see it again after this season’s bushfire emergency.




Read more:
The bushfires are horrendous, but expect cyclones, floods and heatwaves too


Large areas of northeast Victoria have been burnt. While this region accounts only for 2% of Murray-Darling Basin’s entire land area, water flowing in from northeast Victorian streams (also known as in-flow) contributes 38% of overall in-flows into the Murray-Darling Basin.

Fire debris flowing into Murray-Darling Basin will exacerbate the risk of fish and other aquatic life dying en masse as witnessed in previous years..

What will flow into waterways?

Generally, bushfire ash comprises organic carbon and inorganic elements such as nitrogen, phosphorous and metals such as copper, mercury and zinc.

Sediment rushing into waterways can also contain large amounts of soil, since fire has consumed the vegetation that once bound the soil together and prevented erosion.

And carcinogenic chemicals – found in soil and ash in higher amounts following bushfires – can contaminate streams and reservoirs over the first year after the fire.

A 2014 post-fire flood in a Californian stream.

How they harm aquatic life

Immediately following the bushfires, we expect to see an increase in streamflow when it rains, because burnt soil repels, not absorbs, water.

When vast amounts of carbon are present in a waterway, such as when carbon-loaded sediments and debris wash in, bacteria rapidly consumes the water’s oxygen. The remaining oxygen levels can fall below what most invertebrates and fish can tolerate.

These high sediment loads can also suffocate aquatic animals with a fine layer of silt which coats their gills and other breathing structures.

Habitats are also at risk. When sediment is suspended in the river and light can’t penetrate, suitable fish habitat is diminished. The murkier water also means there’s less opportunity for aquatic plants and algae to photosynthesise (turn sunshine to energy).




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What’s more, many of Australia’s waterbugs, the keystone of river food webs, need pools with litter and debris for cover. They rely on slime on the surface of rocks and snags that contain algae, fungi and bacteria for food.

But heavy rain following fire can lead to pools and the spaces between cobbles to fill with silt, causing the waterbugs to starve and lose their homes.

This is bad news for fish too. Any bug-eating fish that manage to avoid dying from a lack of oxygen can be faced with an immediate food shortage.

Many fish were killed in Ovens River after the 2003 bushfires from sediment slugs.
Arthur Rylah Institute, Author provided

We saw this in 2003 after the sediment slug penetrated the Ovens River in the north east Murray catchment. Researchers observed dead fish, stressed fish gulping at the water surface and freshwater crayfish walking out of the stream.

Long-term damage

Bushfires can increase the amount of nutrients in streams 100 fold. The effects can persist for several years before nutrient levels return to pre-fire conditions.

More nutrients in the water might sound like a good thing, but when there’s too much (especially nitrogen and phosphorous), coupled with warm temperatures, they can lead to excessive growth of blue-green algae. This algae can be toxic to both people and animals and often closes down recreational waters.




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Strength from perpetual grief: how Aboriginal people experience the bushfire crisis


Large parts of the upper Murray River catchment above Lake Hume has burnt, risking increases to nutrient loads within the lake and causing blue-green algae blooms which may flow downstream. This can impact communities from Albury all the way to the mouth of the Murray River in South Australia.

Some aquatic species are already teetering on the edge of their preferred temperature as stream temperatures rise from climate change. In places where bushfires have burnt all the way to the stream edge, decimating vegetation that provided shade, there’ll be less resistance to temperature changes, and fewer cold places for aquatic life to hide.

Cooler hide-outs are particularly important for popular angling species such as trout, which are highly sensitive to increased water temperature.

Ash blanketing the forest floor can end up in waterways when it rains.
Tarmo Raadik

But while we can expect an increase in stream flow from water-repellent burnt soil, we know from previous bushfires that, in the long-term, stream flow will drop.

This is because in the upper catchments, regenerating younger forests use more water than the older forests they replace from evapotranspiration (when plants release water vapour into the surrounding atmosphere, and evaporation from the surrounding land surface).

It’s particularly troubling for the Murray-Darling Basin, where large areas are already enduring ongoing drought. Bushfires may exacerbate existing dry conditions.

So what can we do?

We need to act as soon as possible. Understandably, priorities lie in removing the immediate and ongoing bushfire threat. But following that, we must improve sediment and erosion control to prevent debris being washed into water bodies in fire-affected areas.




Read more:
In fact, there’s plenty we can do to make future fires less likely


One of the first things we can do is to restore areas used for bushfire control lines and minimise the movement of soil along access tracks used for bushfire suppression. This can be achieved using sediment barriers and other erosion control measures in high risk areas.

Longer-term, we can re-establish vegetation along waterways to help buffer temperature extremes and sediment loads entering streams.

It’s also important to introduce strategic water quality monitoring programs that incorporate real-time sensing technology, providing an early warning system for poor water quality. This can help guide the management of our rivers and reservoirs in the years to come.

While our current focus is on putting the fires out, as it should be, it’s important to start thinking about the future and how to protect our waterways. Because inevitably, it will rain again.The Conversation

Paul McInerney, Research scientist, CSIRO; Gavin Rees, , CSIRO, and Klaus Joehnk, Senior research scientist, CSIRO

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Bushfires threaten drinking water safety. The consequences could last for decades



Warnings about poor drinking water quality are in place in some areas affected by the bushfires.
From shutterstock.com

Stuart Khan, UNSW

Bushfires pose serious short- and long-term impacts to public drinking water quality. They can damage water supply infrastructure and water catchments, impeding the treatment processes that normally make our water safe to drink.

Several areas in New South Wales and Victoria have already been issued with warnings about the quality of their drinking water.

Here’s what we know about the short- and long-term risks.




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Short-term risks

Bushfires can damage or disrupt water supply infrastructure as they burn. And the risks can persist after the fires are out.

A loss of power, for example, disables important water treatment processes such as chlorine disinfection, needed to kill microorganisms and make our water safe to drink.

Drinking water for the towns of Eden and Boydtown on the NSW south coast has been affected in this way over recent days. Residents have been advised to boil their water before drinking it and using it for cooking, teeth brushing, and so on.

Other towns including Cobargo and Bermagui received similar warnings on New Year’s Eve.




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In some cases, untreated water, straight from a river supply, may be fed directly into drinking water systems. Water treatment plants are bypassed completely, due to damage, power loss, or an inability to keep pace with high volumes of water required for firefighting.

We’ve seen this in a number of southern NSW towns this week including Batlow, Adelong, Tumbarumba, and the southern region of Eurobodalla Council, stretching from Moruya to Tilba. Residents of these areas have also been urged to boil their drinking water.

Untreated river water, or river water which has not been properly disinfected with chlorine, is usually not safe for drinking in Australia. Various types of bacteria, as well as the parasites giardia and cryptosporidium, could be in such water.

Animals including cattle, birds and kangaroos can excrete these microorganisms into river water. Septic tanks and sewage treatment plants may also discharge effluents into waterways, adding harmful microorganisms.

Human infection with these microorganisms can cause a range of illnesses, including gastrointestinal diseases with symptoms of diarrhoea and vomiting.




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Long-term risks

Bushfires can damage drinking water catchments, which can lead to longer term threats to drinking water. Drinking water catchments are typically forested areas, and so are vulnerable to bushfire damage.

Severe impacts to waterways may not occur until after intense rainfall. Heavy rain can wash ash and eroded soil from the fires into waterways, affecting drinking water supplies downstream.

For example, bushfire ash contains nutrients, such as nitrogen and phosphorous. Increased nutrient concentrations can stimulate the growth of cyanobacteria, commonly known as “blue-green algae”.

Cyanobacteria produce chemicals which may cause a range of water quality problems, including poor taste and odour. Some cyanobacteria can produce toxic chemicals, requiring very careful management to protect treated drinking water.

Boiling water will kill microorganisms, but not chemical substances.
From shutterstock.com

Many water treatment plants include filtration processes to filter small suspended particles from the water. But an increase in suspended particles, like that which we see after bushfires, would challenge most filtration plants. The suspended particles would be removed, but they would clog the filters, requiring them to be more frequently pulled from normal operation and cleaned.

This cleaning, or backwashing, is a normal part of the treatment process. But if more time must be spent backwashing, that’s less time the filters are working to produce drinking water. And if the rate of drinking water filtration is slowed and fails to keep pace with demand, authorities may place limitations on water use.




Read more:
The bushfires are horrendous, but expect cyclones, floods and heatwaves too


Boiling water isn’t always enough

In order to reduce the risk of gastrointestinal and other illnesses, water suppliers and health departments may issue a boil water alert, as we’ve seen in the past week. Bringing water to a “rolling boil” can reliably kill most of the microorganisms of concern.

In cases where water may be contaminated with chemical substances rather than microorganisms, boiling is usually not effective. So where there’s a risk of chemical contamination, public health messages are usually “do not drink tap water”. This means bottled water only.

Such “do not drink” alerts were issued this week following bushfire impacts to water treatment plants supplying the Victorian towns of Buchan and Omeo.




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Impacts to catchments from bushfires and subsequent erosion can have long-lasting effects, potentially worsening untreated drinking water quality for many years, even decades.

Following these bushfires, many water treatment plant operators and catchment managers will need to adapt to changed conditions and brace for more extreme weather events in the future.The Conversation

Stuart Khan, Professor of Civil & Environmental Engineering, UNSW

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Fish kills and undrinkable water: here’s what to expect for the Murray Darling this summer



Dry conditions will make for a difficult summer in the Murray Darling Basin.
AAP/Dean Lewins

Jamie Pittock, Australian National University

A grim summer is likely for the rivers of the Murray-Darling Basin and the people, flora and fauna that rely on it. Having worked for sustainable management of these rivers for decades, I fear the coming months will be among the worst in history for Australia’s most important river system.

The 34 months from January 2017 to October 2019 were the driest on record in the basin. Low water inflows have led to dam levels lower than those seen in the devastating Millennium drought.

No relief is in sight. The Bureau of Meteorology is forecasting drier-than-average conditions for the second half of November and December. Across the summer, rainfall is also projected to be below average.

So let’s take a look at what this summer will likely bring for the Murray Darling Basin – on which our economy, food security and well-being depend.

A farmer stands in the dry river bed of the Darling River in February this year.
Dean Lewins/AAP

Not a pretty picture

As the river system continues to dry up and tributaries stop flowing, the damaging effect on people and the environment will accelerate. Mass fish kills of the kind we saw last summer are again likely as water in rivers, waterholes and lakes declines in quality and evaporates.

Three million Australians depend on the basin’s rivers for their water and livelihoods. Adelaide can use its desalination plants and Canberra has enough stored water for now. But other towns and cities in the basin risk running out of water.




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Governments were warned well before the drought to better secure water supplies through infrastructure and other measures. But the response was inadequate.

Some towns such as Armidale in New South Wales have been preparing to truck water to homes, at great expense. Water costs will likely increase to pay for infrastructure such as pumps and pipelines. The shortages will particularly affect Indigenous communities, pastoralists who need water for domestic use and livestock, irrigation farmers and tourism business on the rivers.

Water in major storages as reported at 13 November 2019.
Murray Darling Basin Authority

As we saw during the Millennium drought, when wetland soils dry some sediments will oxidise to form sulfuric acid. This kills fauna and flora and can make water undrinkable.

Red gum floodplain forests and other wetland flora will continue to die. Most of these wetlands have not had a drink since 2011. The desiccation, due to mismanagement and drought, is likely to see the return of hypersalinity – a huge excess of salt in the water – with river flows too weak to flush the salt out to sea.




Read more:
Murray-Darling report shows public authorities must take climate change risk seriously


If drought-breaking rains do come, as they did in 2010-11, this would create a new threat. Floodwaters would inundate leaf litter on the floodplains, triggering a bacterial feast that depletes the water of oxygen. These so-called “blackwater” events kill fish, crayfish and other aquatic animals.

The risk of blackwater events has largely arisen because government authorities have failed to manage water as they had agreed. In particular, the NSW and Victorian governments have not worked with farmers to allow managed river flows to inundate floodplains.

The prospect of thousands of dead fish in the Murray Darling Basin looms large again this summer.
AAP/GRAEME MCCRABB

How did we get here?

The severity and impacts of this drought should not come as a surprise. In the 1980s, the CSIRO’s first projections of climate change impacts in the basin foreshadowed what is unfolding now.

Despite the decades-old warnings, water management authorities in some catchments favoured water extraction by irrigators over rural communities, pastoralists and the environment. For example, the NSW Natural Resources Commission in September found that state government changes to water regulations brought forward the drying up of the Darling River by three years.




Read more:
We can’t drought-proof Australia, and trying is a fool’s errand


Since the basin plan was adopted in 2012 our federal and state political leaders have reduced the volume of real water needed to keep the rivers healthy, supply water to people and flush salt out to sea. For example, in May 2018 the federal government and Labor opposition agreed to reduce water allocated to the environment by 70 billion litres a year on average, without a legitimate scientific basis.

The basin plan is based on historical river flow records, without explicitly allowing for diminished inflows resulting from climate change. Australian water management has followed what’s been termed a “hydro-illogical cycle” where drought triggers reform, but government leaders lose attention once it rains. This suggests meaningful reform must be implemented when drought is occurring and politicians are under pressure to respond.

Severe drought and mismanagement means a dire summer for the Murray-Darling river system.
Dean Lewins/AAP

How to fix this

Governments must assume that climate-induced drought conditions in the basin are the new normal, and plan for it.

Action should include:

  • Revising water allocations consistent with climate change projections

  • Investing in managed aquifer recharge to supply more towns with reliable and safe water

  • Restoring rivers by reallocating enough water to sustain their health

  • Increasing wetland resilience by reconnecting rivers to their floodplains in wetter years

  • Improving river health, such as by fencing out livestock.

Investing in these adaptation actions now would provide jobs during the drought and prepare Australia for a much drier future in the Murray-Darling Basin.The Conversation

Jamie Pittock, Professor, Fenner School of Environment & Society, Australian National University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

‘New Bradfield’: rerouting rivers to recapture a pioneering spirit


Waters from the Herbert River, which runs toward one of northern Australia’s richest agricultural districts, could be redirected under a Bradfield scheme.
Patrick White, Author provided

Patrick White, James Cook University and Russell McGregor, James Cook University

The “New Bradfield” scheme is more than an attempt to transcend environmental reality. It seeks to revive a pioneering spirit and a nation-building ethos supposedly stifled by the bureaucratic inertia of modern Australia.

This is not a new lament. Frustrated by bureaucracy, politicians in North Queensland have long criticised the slow pace of northern development.




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In 1950, northern local governments blamed urban lethargy. One prominent mayor complained:

… these young people lack the pioneering spirit of their forebears, preferring leisure and pleasure to hardships and hard work.

These sentiments were inspired by an agrarian nostalgia that extolled toil and toughness. Stoic responses to the challenges of life on the land are part of the Australian legend.

With drought devastating rural and urban communities and a state election looming in Queensland in 2020, both sides of politics have proposed a “New Bradfield” scheme.

An idea with 19th-century origins

Civil engineer John Bradfield devised the original scheme in 1938. His plan would swamp inland Australia by reversing the flow of North Queensland’s rivers. Similar proposals go back to at least 1887, when geographer E.A. Leonard recommended the Herbert, Tully, Johnstone and Barron rivers be turned around to irrigate Australia’s “dead heart”.

Blencoe Falls, on a tributary of the Herbert River, North Queensland, during the dry season.
Patrick White, Author provided

As the “dead heart” became the “Red Centre” in the 1930s, populist writers revived the dreams of big irrigation schemes.

These schemes have always been contested on both environmental and economic grounds. A compelling history of Bradfield’s proposal reveals many errors and miscalculations. But what the scheme lacked in substance it made up for in grandiose vision.

Water dreaming has been a powerful theme in Australian history. The desire to transform desert into farmland retains appeal and discredited schemes like Bradfield keep reappearing.




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Contempt for nature and country

While less ambitious than the original plan, the “New Bradfield” scheme still engineers against the gradient of both history and nature. It would have irreversible consequences for Queensland’s environment, society and culture.

What’s more, the new scheme manifests much the same mindset as the old.

It’s an attitude that privileges the conquest of nature: in this case literally up-ending geography by turning east-flowing rivers westward. Its celebration of the human struggle against defiant nature reprises the pioneering ethos.

Like many pioneers, “New Bradfield” proposals disregard the interests and land-management practices of Indigenous people. The bushfires ravaging the eastern states show the folly of ignoring traditional ways of caring for country .

Overlooking native title realities can also cost governments and communities.




Read more:
Remote Indigenous Australia’s ecological economies give us something to build on


Polarising debate neglects more viable projects

“New Bradfield” is promoted as “an asset owned by all Queenslanders for all Queenslanders”. But environmental destruction and disputes over water sales in the Murray-Darling Basin sound a warning.

The Queensland Farmers Federation has cautiously welcomed the new scheme. Others have dismissed it as a “pipe dream”.

Thus, northern Australia again sits amid a polarised debate about its utility to the nation. Such polarising contests diminish the likelihood of more viable projects being implemented.

Extravagant expectations of “untapped” northern resources have been proffered for nearly two centuries. Distant governments have fantasised the Australian tropics as a land of near-limitless potential. Northern communities have many times been disappointed by the results.

Today’s promises to “drought-proof” large areas of Queensland rely on similar images. “Drought-proofing” aims to keep people on the land but often defies economic and social reality.




Read more:
We can’t drought-proof Australia, and trying is a fool’s errand


Dam developments have an underwhelming record

The “New Bradfield” rhetoric echoes the inflated expectations of myriad disappointing northern development plans in the past. The Ord River project was touted as an agricultural wonder that would put hundreds of thousands of farmers into the Kimberley. Its success lies forever just over the horizon.

Much closer to the present proposal is the Burdekin Falls Dam. It sits in the lower reaches of the same river earmarked for the Hells Gates Dam that would feed the “New Bradfield” scheme. Damming Hells Gates has been advocated since at least the 1930s and has new supporters.

The proposed site for Hells Gates Dam is on Gugu Badhun country on the Burdekin River.
Dr Theresa Petray, Author provided

Back in the 1950s, damming the Burdekin was expected to generate hydro-electric power and irrigate vast swathes of farmland. After decades of political squabbling, the dam was completed in 1988. It does not generate hydro power. Although it irrigates some land downstream, the anticipated huge agricultural expansion never happened.

The Burdekin Falls Dam has helped the regional economy and could help to overcome the water shortages of the nearby city of Townsville. But it has not met the inflated expectations widely proffered decades earlier. The benefits that would flow from another dam further upstream are likely to be even more meagre.




Read more:
Damming northern Australia: we need to learn hard lessons from the south


Grandiose visions of northern development have a habit of failing. A “New Bradfield” scheme, animated by an old pioneering ethos, is unlikely to be different.

Drought-affected communities would derive more benefit from sober proposals that acknowledge the past, integrate Indigenous knowledge and incorporate agricultural innovation.The Conversation

Patrick White, PhD Candidate in History and Politics, James Cook University and Russell McGregor, Adjunct Professor of History, James Cook University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Researchers allege native logging breaches that threaten the water we drink



Researchers have uncovered what appears to be widespread logging of steep slopes in Victoria, which has the potential to damage critical water supplies.
Chris Taylor, Author provided

David Lindenmayer, Australian National University and Chris Taylor, Australian National University

The Victorian government’s logging business is cutting native forests on steep slopes, in an apparent rule breach that threatens water supplies to Melbourne and rural communities.

Our research indicates that across vital water catchments in the Central Highlands of Victoria, state-owned VicForests is logging native forest on slopes steeper than is allowed under the code of practice. Logging also appears to be occurring in other areas supposedly excluded from harvesting.

Logging operations are prohibited from taking trees from slopes steeper than a certain gradient, because it can lead to soil damage which compromises water supplies. There are far better commercial alternatives to this apparent contravention of the rules, which must immediately cease.

A steep slope recently logged measuring 33 degrees on site near Mount Matlock in the Upper Goulburn Catchment.
Chris Taylor

Logging on steep slopes matters

Water catchments are areas where the landscape collects water. They are defined by natural features such as mountain ridgelines and valleys. Rain drains into rivers and streams, which supply water to reservoirs.

Forest cover protects the soil in water catchments by preventing erosion and other damage which can pollute water.

Areas that provide water for drinking, agriculture and irrigation are known in Victoria as special water supply catchments. Under the state’s Code of Forest Practice, logging in these catchments is prohibited on slopes steeper than 30 degrees (or 25 degrees in some catchments). VicForests claims it does not log trees on such slopes.

Sobering evidence

Water in some affected catchments ends up in Melbourne’s drinking water supply.

We analysed slopes across multiple special water supply catchments. We first examined the relationships between slope and logging disturbance using data from the Victorian government, Geoscience Australia, and the European Space Agency. To confirm the results, we visited multiple sites in the Upper Goulburn catchment, which supplies water to Eildon Reservoir, to measure the slopes ourselves.

We found logging in many areas steeper than 30 degrees. In larger catchments such as the Upper Goulburn, around 44% of logged areas contained slopes exceeding this gradient. In many instances, logged slopes were far steeper than 30 degrees and some breaches covered many hectares.

In the Thomson, Melbourne’s largest water supply catchment, 35% of logged areas contained slopes steeper than 30 degrees.

We also found areas that should have been formally excluded from logging but where the forest had been cut. Many of these exclusion zones were around steep slopes. In the Upper Goulburn catchment, nearly 80% of logged areas contained exclusion zones that should not have been cut.

Recently logged areas near Mount Matlock in the Upper Goulburn Water Catchment. The top map shows where we detected slopes exceeding 30 degrees in logged areas (red). The bottom map shows areas designated by the Victorian government as exclusion zones (magenta).
DELWP 2019, ESA 2019, Gallant et al. 2011

Why is this happening?

Last week, VicForests rejected our allegations of slope breaches. VicForests claimed it was complying with a rule under which 10% of an area logged can exceed 30 degrees. This rule applies to general logging areas; our interpretation is this exemption does not apply to the special water supply catchments.

Forest on steep and rugged terrain is economically marginal for wood production because the trees are relatively short and widely spaced. Almost all timber from these areas is pulpwood for making paper.

So why are such areas being logged at the risk of compromising the water catchments that supplies Melbourne and regional Victoria?

We suspect pressure to log steep terrain is tied to the Victorian government’s legal obligation to provide large quantities of pulp logs for making paper until the year 2030 (coincidentally the year the government plans to phase out native forest logging).

This pressure is reflected in recent reductions in log yields. Some commentators have blamed efforts to protect the critically endangered Leadbeater’s possum for this trend. However, only 0.17% of the 1.82 million hectares of forest allocated to VicForests for logging has been taken out of production to protect this species.

In our view, other possibilities for declining yields are past over-cutting and bushfires. VicForests failed to take into account the effects of fire on its estimates of sustained timber yield – despite some of Victoria’s forests being some of the world’s most fire-prone environments.

There are alternatives

Pulp logs sourced from native forests is not a commercial necessity; there are viable alternatives. Victorian hardwood plantations produced 3.9 million cubic metres of pulp logs last year. Most of this was exported.

If just some of these logs were processed in Victoria, it would be enough to replace the pulpwood logged from native forests several times over. Plantation wood is better for making paper than native forest logs, and processing the logs in Victoria would boost regional employment.

Degrading soil and water by logging steep terrain is not worth the short-term, marginal gain of meeting log supply commitments, especially when there are viable alternatives. The Victorian government must halt the widespread breaches of its own rules.


In a statement, VicForests said it “strongly rejects” the allegations raised by the authors.

In addition to the refutations included in this article, the company said:

  • Any concerns about its practices should be referred to the Office of the Conservation Regulator

  • VicForests does very little harvesting in catchments, where restrictions are in place

  • In the Thompson catchment, VicForests only harvests on average 150ha a year out of about 44,000ha in the catchment – which is 0.3%, or around 3 trees in 1000

  • VicForests only asks contractors to harvest on slopes if it complies with regulation.The Conversation

David Lindenmayer, Professor, The Fenner School of Environment and Society, Australian National University and Chris Taylor, Research Fellow, Fenner School of Environment and Society, Australian National University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

80% of household water goes to waste – we need to get it back


Roberta Ryan, University of Technology Sydney

As regional Australian towns face the prospect of running out of water, it’s time to ask why Australia does not make better use of recycled wastewater.

The technology to reliably and safely make clean, drinkable water from all sources, including sewage, has existed for at least a decade. Further, government policy has for a long time allowed for recycled water to ensure supply.




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The greatest barrier to the widespread use of recycled wastewater is community acceptance. Research from around the world found the best way to overcome reluctance is to embrace education and rigorously ensure the highest quality water treatment.

In 2006 Toowoomba voted against introducing recycled water, despite extensive drought gripping the area.
Allan Henderson/Flickr, CC BY

Why not use stormwater?

Many people are happy to use recycled stormwater, while being reluctant to cook, drink or wash with recycled household wastewater. But there are technical, cost and supply issues with relying on stormwater to meet our country’s water needs. Stormwater has to be cleaned before it is used, the supply can be irregular as it is reliant upon rain, and it has to be stored somewhere for use.

On the other hand, household wastewater (which is what goes into the sewerage system from sinks, toilets, washing machines and so on) is a more consistent supply, with 80% or more of household water leaving as wastewater.

Furthermore, wastewater goes to treatment plants already, so there is a system of pipes to transport it and places which already treat it, including advanced treatment plants that can treat the water to be clean enough for a range of purposes. There are strong economic, environmental and practical arguments for investing more effort in reusing wastewater to meet our water supply needs.

This water can be used for households, industry, business and agriculture, greening public spaces, fighting fires, and topping up rivers or groundwater.

The water cycle

Technically, all water is recyled; indeed we are drinking the same water as the dinosaurs. Put very simply, water evaporates, forms clouds and falls as rain, and is either absorbed into the earth and captured underground or filtered through rock and goes back again into oceans and rivers.

When we capture and reuse water, we are not making more water, but speeding up the water cycle so we can reuse it more quickly.

Not pictured: the many, many animals and people every drop of water has passed through over millennia.
Wikimedia Commons, CC BY-SA

We do already reuse wastewater in Australia, with many parts of regional Australia cleaning wastewater and releasing it into rivers. That water is then extracted for use by places downstream.

Despite this, there have been significant community objections to building new infrastructure to reuse wastewater for household use. In 2006, at the height of the Millennium drought, Toowoomba rejected the idea entirely.

However, since then a scheme has been successfully established in Perth. We must examine these issues again in light of the current drought, which sees a number of Australian regional centres facing the prospect of running out of water.




Read more:
It takes a lot of water to feed us, but recycled water could help


Lessons from overseas

Singapore has had enormous success in reusing wastewater for all kinds of purposes.
EPA/HOW HWEE YOUNG

Despite initial reluctance, many places around the world have successfully introduced extensive wastewater recycling. Places such as Singapore, Essex, California, New Mexico, and Virginia widely use it.

Recent research from the Water Services Association of Australia, working with other research bodies, found several key lessons.

Firstly, the language we use is important. Phrases like “toilet to tap” are unhelpful as they don’t emphasise the extensive treatment processes involved.




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The social media and news outlets can play an significant role here. In Orange County, California, wastewater was introduced through a slow process of building acceptance. Influential individuals were enlisted to explain and advocate for its uses.

Secondly, communities need time and knowledge, particularly about safety and risks. Regulators play an important role in reassuring communities. In San Diego, a demonstration plant gave many people the opportunity to see the treatment process, drink the water and participate in education.

We need to go beyond information to deep consultation and education, understanding where people are starting from and acknowledging that people
from different cultures and backgrounds may have different attitudes.

El Paso successfully introduced wastewater through strong engagement with the media and significant investment in community education, including explaining the water cycle.

Finally, quality of the water needs to be great and it needs to come from a trustworthy source. The more it happens, and people know that, the more likely they are to feel reassured.




Read more:
More of us are drinking recycled sewage water than most people realise


It’s clear the public expect governments to plan and act to secure our future water supply. But we can’t just impose possibly distasteful solutions – instead, the whole community needs to be part of the conversation.The Conversation

Roberta Ryan, Professor, UTS Institute for Public Policy and Governance and UTS Centre for Local Government, University of Technology Sydney

This article is republished from The Conversation under a Creative Commons license. Read the original article.