JF Aus,

"Sewage nutrient overload pollution is not a "threat" to the GBR because sewage and land use nutrient overload is already the fundamental cause already killing coral, leading to 'bleaching'."
If that were true, it couldn't not be a threat!

But nutrient overload causes embrittlement, not bleaching. Bleaching is the result of the coral expelling the symbiotic algae due to the stress it causes when the water is too hot. That much is well known, and confirmed by experimentation. Just because coral can cope with extra heat for a few hours doesn't mean it can withstand it for weeks and months at a time!

It is far from the only threat. Others include sedimentation, crown of thorns starfish, ocean acidification and of course embrittlement.

"Agricultural runoff only occurs in association with rain on this very dry country."
And despite it being very dry for a lot of the time, there is significant rain.

"And presently there is a drought in Queensland, yet the worst bleaching."
Because bleaching is caused by heat.

"I think Landline is a good program. But have they reported why farmers are being blamed for GBR nutrient pollution while nutrient dumped daily from sewage outfalls is not measured and included in the total loading that is resulting in algae blooms and damage?"
Firstly, not being the only source of pollution does not absolve them of the responsibility for the pollution they cause.
Secondly, AIUI that's by far the biggest cause.
Thirdly, your use of the term "sewage outfalls" implies that the sewage is going into the sea untreated, which seems unlikely to me. Do you mean effluent outfalls?
Fourthly, what evidence do you have that nutrient levels in that are going unmonitored?

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ttbn,

Australia is financially sovereign. We can afford to build whatever we want. We can create our own good times.

Rhian,

I can't understand why there was any support for that "canal" proposal (though AIUI it was actually proposed to be an aqueduct). But pipelines south from the Kimberley to serve remote outback communities and mines still seem like a good idea.

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Yuyutsu, China had much more of those undesirable things when it had less "nation".

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Rhosty, are you aware that those tide figures are the maxima? Most of the time they're much less.

The effect of your plan on the groundwater would be devastating.

Aidan,

"Threat" is a word indicating something is going to happen, one split second away or years away. Relevant damage to the GBR has been and is already happening.

Nutrient pollution is feeding epiphyte growth shutting down photosynthesis in seagrass, it has already killed most seagrass nurseries that are supposed to be the primary supplier of small fish to feed fish and animals including baleen whales.

Nutrient pollution is also feeding invasive algae blooms that cover coral and exhaust available oxygen, suffocating the coral polyp and coral's own zooanthellae algae.
A dead zone occurs, some small some covering an entire reef.
Smothered dead polyp and zooanthellae falls away, expelled they say. Sunlight and salt water then bleaches the limestone.

Warmisters declare heat is killing algae.
It is absurd algae inextricably linked to nutrient and coral devastation is being so ignored.
And if heat is doing the killing then agri runoff has nothing to do with it, or does it?

Absolvement? Farming is essential. Farmers do not waste fertilizer or kill their crops with too much of it.
The unnecessary wasted nutrient is coming EVERY day from sewage.
Evidence indicates about 90 percent of treated sewage is not treated to remove nutrient.
Condoms, tomato seeds, the occasional diamond ring, and other plastic waste is removed. Lumps are tumbled off to the side for landfill. Some works use bio digesters and membrane filters but they do not remove dissolved nutrient from coastal or river outfalls.

Evidence, for example. Evidence of the nutrient loading being suspended during Gladstone port works was not scientifically measured and assessed, measurement was taken about once a week, not daily, not downstream where nutrient flow would be expected.

The northern Great Barrier Reef is absolutely downstream from Gladstone.

Focus at Gladstone has been on sediment, not dissolved nutrient than can be transported vast distances by surface and other currents.

Google; nutrient pollution.

And see:
http://news.bbc.co.uk/earth/hi/earth_news/newsid_9070000/9070148.stm

How can coastal associated tourism and towns and industry be sustained or built when problems causing damage to water are not being seen and told by major media in this country?

JF Aus,

Damage to the GBR is already happening. The problem now is that there's so much damage it might not recover. Therefore things that cause damage are threats.

"Nutrient pollution is feeding epiphyte growth shutting down photosynthesis in seagrass,"
In a few (relatively small) areas, yes, but not on a large scale, at least in Australian waters.

I suggest you read: http://seagrasswatch.org/Info_centre/Publications/pdf/seagrass_in_australia.pdf

"Nutrient pollution is also feeding invasive algae blooms that cover coral and exhaust available oxygen, suffocating the coral polyp and coral's own zooanthellae algae. A dead zone occurs, some small some covering an entire reef."
Have you any evidence this is happening on the Great Barrier Reef?

"Smothered dead polyp and zooanthellae falls away, expelled they say."
No, a dead polyp is unable to expel anything. Inability to support zooanthellae is not the same as expulsion.

"Warmisters declare heat is killing algae."
Marine biologists declare heat is killing coral.

"It is absurd algae inextricably linked to nutrient and coral devastation is being so ignored."
Who says it's being ignored? ITYF it's been well studied due to the problem of coral embrittlement.

"And if heat is doing the killing then agri runoff has nothing to do with it, or does it?"
I don't know (IANAMB). It may affect susceptibility but it certainly isn't the primary cause.

"Absolvement? Farming is essential. Farmers do not waste fertilizer or kill their crops with too much of it."
I didn't claim farming wasn't essential, and I certainly didn't suggest that they were so grossly incompetent as to apply enough fertiliser to kill their crops! But the problem of agricultural runoff is evidence that some fertilizer is wasted.

"Evidence indicates about 90 percent of treated sewage is not treated to remove nutrient."
What evidence is that?

Anyone contributing to the destruction of the GBR should go directly to jail.
I'd like to think that future Australians will be able to enjoy that place so to hell with anyone who does not respect it.

Aidan

it's hard enough to make productive use of Kimberley water for farming even in the Kimberley - look at the hundreds of millions government has spend on the Ord irrigation schemes. I suspect a cost-benefit analysis of that would not look pretty.

I'm not sure miners need Kimberley water. Its a lot cheaper to extract groundwater. Many of the more mature iron ore mines in the Pilbara are now mining below the water table, and dewatering is becoming a challenge. They have too much water, not too little.

http://www.parliament.wa.gov.au/publications/tabledpapers.nsf/displaypaper/3913625ce705f2e0a59df0e848257f02000d5aec/$file/tp-3625.pdf