Worst drought ever

[chops_a_must]

Smurf

Seems to me that a 66% reduction in rainfall in a relatively short period of time is most likely due to the volatile and extreme nature of the Australian climate.
If it was due to long term climate change, wouldn't it stand to reason that the change would be more gradual?

No!

Anyone that knows anything about WA would have heard about the Leeuwin Current.

It's the only thing that makes SW WA even remotely inhabitable. Any slight change in weather patterns can potentially permanently damage the current, and jeoperdise the eco-system here. Without it we would have almost no rain, and because of its uniqueness, and the impact on it from many many climates and ocean cycles, it is the most important bell weather (pardon the pun) for temperate Australian weather. Normal Leeuwin Current = good rainfall for all of southern Australia.

And the Leeuwin Current seems to be on the point of serious harm because of various climatic changes. The best managed fisheries in the world are here, but they are stuffed because the current is no longer assisting with spawning for the lobster etc.

Any climatic change is quick, and has leading indicators like here in WA. Rainfall relies on simple but delicate systems, which means sudden changes that may or may not reverse. Until such point as we get another bumper rock lobster catch, or if we do ever get another, then the climate has changed for the worse in southern Australia. And even in times of no quotas and restrictions, we have not seen current dependent fish stocks in WA at these levels before. Some things to look at and be concerned about....

 

[bunyip]

No!

Anyone that knows anything about WA would have heard about the Leeuwin Current.

It's the only thing that makes SW WA even remotely inhabitable. Any slight change in weather patterns can potentially permanently damage the current, and jeoperdise the eco-system here. Without it we would have almost no rain, and because of its uniqueness, and the impact on it from many many climates and ocean cycles, it is the most important bell weather (pardon the pun) for temperate Australian weather. Normal Leeuwin Current = good rainfall for all of southern Australia.

And the Leeuwin Current seems to be on the point of serious harm because of various climatic changes. The best managed fisheries in the world are here, but they are stuffed because the current is no longer assisting with spawning for the lobster etc.

Any climatic change is quick, and has leading indicators like here in WA. Rainfall relies on simple but delicate systems, which means sudden changes that may or may not reverse. Until such point as we get another bumper rock lobster catch, or if we do ever get another, then the climate has changed for the worse in southern Australia. And even in times of no quotas and restrictions, we have not seen current dependent fish stocks in WA at these levels before. Some things to look at and be concerned about....

I'd never heard of the Leeuwin Current. Very interesting.
I jumped on the net and did some reading, and came to the following conclusions.....

An El Niño -Southern Oscillation event causes drought across northern Australia. Drought reduces the strength of the Leeuwin Current which originates in the tropics and flows southward along the WA coast, then east into the Great Australian Bight. The weaker flow in the current has an adverse effect on the lobster breeding cycle, and causes below average rainfall in southern Australia.
Conversely, La Nina (wet) years cause stronger flow in the current....good news for both the lobsters and the rainfall in southern Australia.

Climatologists tell us that a prolonged pattern of El Niño drought-causing years is a normal part of our climate. Similarly, a prolonged pattern of wet La Nina years is also quite normal.
They also tell us that it's normal for these patterns to last much longer than our records of the last two hundred years would indicate.

We could see a sudden reversal of these El Niño drought years that have plagued much of northern Australia for the last 10 to 20 years.
Perhaps the heavy monsoon season in the north this year is an indication that we've turned the corner at last, and are about to go into a run of La Nina wet years. If we do in fact experience a prolonged run of wet years across the north, the resulting improvement in the Leeuwin Current could have quite a dramatic and positive effect on the lobster breeding cycle, and also on the rainfall across southern regions.

Am I on the right track here, or am I talking through my hat? I confess to having very little knowledge of either lobster breeding patterns or the Leeuwin Current. In fact I knew nothing about either of them before reading that article on the net a couple of hours ago.

Below in bold print an extract from that article.

The Leeuwin Current is also known to be influenced by El Niño conditions, with slightly lower sea levels along the Western Australian coast and a weaker Leeuwin Current.

Measurements across the broad continental shelf at North West Cape confirm the low-salinity Leeuwin flows along the outer North West Shelf most strongly between February and June. Strong winds to the northeast along the shelf can retard or even reverse the currents.
By late winter and early spring the puerulus are carried by ocean currents back to the continental shelf and inshore coastal regions. Earlier studies have shown that settlement of lobster puerulus (small but recognisable rock lobsters) is closely linked with variations in the strength of the Leeuwin Current, which in turn is associated with El Niño – Southern Oscillation (ENSO) events as well as westerly winds.

During ENSO years, when the Leeuwin Current tends to be weak, puerulus settlement is poor. In so-called La Nina years, on the other hand, the Current tends to flow more strongly and settlement is much greater.

 

[chops_a_must]

Yup. Which is why I said the climate will change quickly, and may or may not snap back.

I had been told that even before this latest el nino cycle, the Leeuwin Current has been distinctly weaker than before european settlement. I'm not sure how they work that out... something to do with sampling from old growth forests I think. And that the current would actually have ceased to exist in the relatively near future anyway. Whether or not we are speeding that process up, who knows?

But I don't think we are out of the woods yet, the breeding season in the fisheries was quite poor by all reports. And we have had one of the hottest and wettest summers here in living memory (I think it has been the hottest on record), certainly the most humid. Which to me indicates we have still had a relatively warm current this summer. I didn't go to the beach pre-christmas this summer, so can't tell if the water was its typical freezing self, (like it should be at that time). So I think it is far too early to tell that we have had a change in southern Australia, because I don't think we have.

 

[Smurf1976]

So I think it is far too early to tell that we have had a change in southern Australia, because I don't think we have.

We've had a change alright... for the worse. At least that's what's going on in Tas - 2007 was wet compared to what we're getting now.

Apart from the East Coast which has had floods (due to an easterly weather pattern for a few days), the rest is getting basically nothing. As an example, Lake Rowallan had 52GWh in storage at the beginning of this year and the power station is out of operation (unplanned breakdown). 7 weeks later and there's still 52GWh in storage - inflows literally zero.

Lake Pedder is another one. The canal is normally closed at -1.45m as this is one of the last storages to be drawn down heavily for aesthetic and recreational reasons. Now it's at -1.47m (canal was closed at -1.45) - evaporation exceeds inflows.

Looking positive though, still 21.1% full across the system this morning so the lights will stay on for quite a while yet. And it might be easier to catch fish if they're all crammed into a smaller volume of water (not sure if that's true in practice).

 

[chops_a_must]

Sorry. I meant a change back to "normal" rainfall.

But certainly we have had a now long term change in our climate, especially in SW WA.

 

[bunyip]

OK.... For the last several months the monsoon has been very active and intense over the tropics and much of the region has had a pretty good wet season.
Has there been any measurable effect on the Leeuwin Current as yet?
Or the rainfall across southern regions?
Or does it take a while for the effect to filter through?

 

[Smurf1976]

OK.... For the last several months the monsoon has been very active and intense over the tropics and much of the region has had a pretty good wet season.
Has there been any measurable effect on the Leeuwin Current as yet?
Or the rainfall across southern regions?
Or does it take a while for the effect to filter through?

The WA situation dates back to the 1970's and there has been a progressively worsening "rain hole" (my term) in Tasmania during the first part of the year also since that time.

In a technical sense in WA it is a lack of wet years bringing down the average. Still get the average years and dry years but the high rainfall years have completely disappeared.

In Tas it is a serious lack of rain centred on March but spreading in both directions (seems to have started 1st Jan this year) but pretty much normal (actually above normal but that's due to cloud seeding) rain once it starts in May or June through to the end of the year.

The WA situation is the worse one in terms of effects thus far but the effect in Tas is certainly measurable and it seems to be hitting the notoriously wet West Coast just as much as the rest - a situation that pretty much rules out it being due to anything done within the state (ie tree plantations etc).

The effects in Tas have been somewhat mitigated until recently with cloud seeding. So we're getting huge drawdowns of water storage during the dry and then almost as impressive refilling during Spring. The top to bottom annual variation for the past few years has been roughly double the historic level due to this.

Trouble is, as the situation worsens cloud seeding is no longer enough to offset it (that is, can't ramp up cloud seeding any more as already doing as much as is practical) and total runoff is now declining. That leaves building more water infrastructure (ie dams, pipelines etc) as the only remaining way to maintain total water availability. Either that or just let it slide and live with the consequences.

For those familiar with the detail, it's an overall situation in Tas eerily familiar to how an oil province depletes. First everything is fine and production rises. Then it levels off. Then the decline starts - first you fight it by injecting something to keep the pressure up (the equivalent of cloud seeding), then you fight it by drilling more wells and opening new fields (comparable to building more dams and pipelines). And then you lose and production enters terminal decline.

That's exactly what will happen if the rainfall trend continues. Cloud seeding is maxed out now. Sure, plenty more dams could be built but if the decline continues then it's ultimately a case of running faster and faster just to maintain current production. Investing more capital just to maintain current income. And then you either go broke or run out of rivers to dam (or oil wells to drill) and the game is up. Same as oil although nobody seriously expected the rainfall to deplete - until now.

I strongly suspect the very similar latitude of SW WA and Tas has something to do with it. That's the only real thing both regions have in common that comes to mind.

My own thinking is that if you draw a line from West to East across Australia then it has moved south considerably. Tas now gets the Summer rainfall that SA used to get - virtually none. As for the monsoon etc in the past few months - all it's done down here is turn dry into a proper drought.

 

[Snakey]

Hmmm...interesting thread...Does anyone know where I can buy shares in umbrellas?
:

 

[bunyip]

The big dry is Tassie is clearly severe and prolonged. But don't dismiss the possibility that it just might be normal. Maybe it hasn't been like this in the last couple of hundred years since we started monitoring and recording the rainfall and the overall climate. But before that - who knows. As I was saying in an earlier post, climatic research is now revealing that very prolonged wet/dry spells and hot/cold spells lasting as much as a couple of centuries, have occurred in Australia in pre-European times.

Now, I don't want to depress you southern blokes by telling you that your current dry spell might last for another 100 years or more! But realistically, considering the new information constantly being uncovered by climate researchers, can we really rule out such a possibility?

When it's exceptionally dry it's easy to convince ourselves that the climate has changed permanently and will never return to decent seasons.
Central Queenslanders have felt that way for the last 17 years.....that's how long since the Fairbairn Dam last overflowed. But water is suddenly charging over the spillway at an impressive rate, and the Central QLD region is so green that you'd swear the recent drought must have been a figment of the imagination.
It can all turn around so suddenly.....such is the erratic nature of the Australian climate.

 

[2020hindsight]

Found this report by UNSW.
One thing I noticed in the summary :-

That hydro power resources are in some jeopardy (nothing new there)
That Lake Eucumbine is lowest since inception / construction

and that water used to generate power will be used (in part) in desalination plants to generate water

PS Also graphs of rainfall and rivers in "SW Aust"
http://www.ceem.unsw.edu.au/content/userDocs/Hugh071015Water_ManagingScarceResource_000.pdf

 

[2020hindsight]

........
damned if I can see a trend there.

 

[Smurf1976]

The big dry is Tassie is clearly severe and prolonged. But don't dismiss the possibility that it just might be normal. Maybe it hasn't been like this in the last couple of hundred years since we started monitoring and recording the rainfall and the overall climate. But before that - who knows. As I was saying in an earlier post, climatic research is now revealing that very prolonged wet/dry spells and hot/cold spells lasting as much as a couple of centuries, have occurred in Australia in pre-European times.

Now, I don't want to depress you southern blokes by telling you that your current dry spell might last for another 100 years or more! But realistically, considering the new information constantly being uncovered by climate researchers, can we really rule out such a possibility?

When it's exceptionally dry it's easy to convince ourselves that the climate has changed permanently and will never return to decent seasons.
Central Queenslanders have felt that way for the last 17 years.....that's how long since the Fairbairn Dam last overflowed. But water is suddenly charging over the spillway at an impressive rate, and the Central QLD region is so green that you'd swear the recent drought must have been a figment of the imagination.
It can all turn around so suddenly.....such is the erratic nature of the Australian climate.

Can't argue with any of that. Totally agreed.

What I'm focusing on though is the practical implications. It doesn't matter if you're in Sydney or Strathgordon the implications are (broadly speaking) the same. Everything was set up based on the notion of rainfall being X with annual variation Y and that a deficiency would persist for no more than Z duration. That's the basis on which everything from major city water supplies, and to a significant extent the city itself, through to agriculture and hydro-electricity has been planned.

I'll use the Tasmanian figures since I have the data. But this in no way suggests that other parts of the country haven't been even more heavily affected.

Hydro Tas records go back to 1914 and other rainfall data for Tas goes back virtually to European settlement. Based on all this data, a few things have always been assumed to be true. Namely that inflows to the hydro-electric catchments will be between 64% and 137% of normal in any given year and that droughts (1) extend for up to 3 years (2) are always followed by a period of above average rainfall and (3) are never as serious in Tasmania as elsewhere in Australia.

And so 54 dams, 28 power stations and numerous canals, weirs, pipelines, penstocks and so on collectively twice the size of the Snowy were built. And as the commercial said, "As long as it keeps raining in the mountains...".

Trouble now is pretty simple. No individual year has yet been outside the 64% - 137% range that's existed for decades. But this 10 year drought blows the others away in terms of duration. A slow, steady grind to the bottom.

It's almost exactly the same with the Murray and elsewhere, I've only used Tas as an example because I have the figures. Everything for the Murray etc was planned on what we knew in the 1940's. Droughts were expected but, just as in Tas, they were to be followed by good rains that would refill the dams. Nobody expected a decade with every single year being dry.

Natural or man-made change I really don't know. But the issue is that we're just not set up to cope with it practically anywhere in the country. .

 

[Smurf1976]

........
damned if I can see a trend there.

That $80 looks rather cheap compared to the price in SA yesterday afternoon. A few cents under $10,000 and stayed there quite a while.

 

[bunyip]

Can't argue with any of that. Totally agreed.


Hydro Tas records go back to 1914 and other rainfall data for Tas goes back virtually to European settlement. Based on all this data, a few things have always been assumed to be true. Namely that inflows to the hydro-electric catchments will be between 64% and 137% of normal in any given year and that droughts (1) extend for up to 3 years (2) are always followed by a period of above average rainfall and (3) are never as serious in Tasmania as elsewhere in Australia.

And so 54 dams, 28 power stations and numerous canals, weirs, pipelines, penstocks and so on collectively twice the size of the Snowy were built. And as the commercial said, "As long as it keeps raining in the mountains...".

Trouble now is pretty simple. No individual year has yet been outside the 64% - 137% range that's existed for decades. But this 10 year drought blows the others away in terms of duration. A slow, steady grind to the bottom.

It's almost exactly the same with the Murray and elsewhere, I've only used Tas as an example because I have the figures. Everything for the Murray etc was planned on what we knew in the 1940's. Droughts were expected but, just as in Tas, they were to be followed by good rains that would refill the dams. Nobody expected a decade with every single year being dry.

Natural or man-made change I really don't know. But the issue is that we're just not set up to cope with it practically anywhere in the country. .

Too true....we're just not set up to handle those really prolonged dry spells where there's no runoff rain for a decade or more. And it's difficult to see how we every could be - how can any dam store enough water to last for say 20 or 30 years during which time there is virtually no runoff. Or - perish the thought - a 50 or 100 year dought.

So then Smurf...what's the answer? Alternative power sources that don't rely on water storages?
And for water, large rainwater storage tanks for every building? Not that this would entirely supply our water needs, but it'd have to drastically relieve the pressure on dams etc wouldn't it. Even during severe drought there's enough rain to run plenty of water off roofs. I have a bore and a huge rainwater tank myself, no town water, but if my bore went dry and I had to rely solely on tank water I could get by quite OK. Particularly if I added a second tank.

Some areas have plenty of water but aren't allowed to use it. Fraser Island, just a few miles off the QLD coast, has dozens of strong fresh water streams flowing into the sea, even in times of drought. A small fraction of this water harvested and piped to the nearby cities would ensure a reliable water supply for that region, without adversely affecting nature. Yet the greenies have Fraser Island locked down....not one drop of Fraser water can be touched for human use. Ridiculous.
I'm conservation-minded myself, but not to the extent of being downright idiotic about it. There has to be some balanced thinking incorporated with conservation.

I've never been to Tassie but I believe you have quite a lot of fresh water flowing into the sea. Could a small portion of this water be harvested for human use, without wrecking the rivers or destroying the surrounding ecosystem?

 

[2020hindsight]

Smurf

Seems to me that a 66% reduction in rainfall in a relatively short period of time is most likely due to the volatile and extreme nature of the Australian climate.
If it was due to long term climate change, wouldn't it stand to reason that the change would be more gradual?

Bunyip
I can't see any reason that the change would be gradual.
We are not talking mono-step adjustments to the system. This is a crazy chaotic world we live in. Trouble is the stats (to normal confidence intervals) are all pointing to the globe warming (IPCC). (as evidenced by a heap of symptoms). Worst levels in Eucumbine for a starter.

The 'extreme nature of the Aus climate' could well become more extreme. Certainly the average is getting hotter.

And today's article - "Early Warning" re global warming etc. - probably should be on some other thread, since some parts of Aus will become wetter and some drier.
http://www.abc.net.au/news/stories/2008/02/21/2168668.htm?section=justin

Garnaut report a call to action, says Brown
Posted 52 minutes ago

Greens leader Bob Brown says the interim report being released today on climate change is another warning about the need to act quickly to cut emissions.

Economics Professor Ross Garnaut will today deliver a report on emissions targets and the creation of an emissions trading scheme. His final report will be delivered in September, but he has already warned that tough action will be needed.

Senator Brown says Professor Garnaut's message is consistent with other studies.

"We either take the action now and gain the benefits like a robust renewable energy industry, like the ability to cut into wasted power so that we have new power available at no new generating cost and with no new pollution," he said. "Or, we suffer bigger consequences to the economy further down the line."

Policy concerns
Some federal Coalition MPs say they are concerned the Government will go too far on climate change once it develops its policy for carbon emission reduction.

Prime Minister Kevin Rudd has committed to a 60 per cent reduction in emissions by 2050.

But the Liberal MP for Kalgoorlie, Barry Hasse, want a more cautious approach.
"I think Rudd's already gone too far on climate change," he said.

"The story yesterday about it not adding to costs, any sort of carbon credit system, not adding to costs of energy and therefore the cost of living, I think is ga-ga land.

"Whether 60 per cent is too much or too little, I simply believe his scheme to afford cuts is going to add to the cost of living."

 

[Smurf1976]

I keep hearing about floods in Qld, rain in NSW etc. Any chance of sending some down to Tas?

over the last four months we have experienced the lowest ever inflows to hydro storages for any November to February period on record.

“In fact, the inflows were less than 20 per cent of those normally received and less than half of the lowest previously experienced.

“As of Monday 3 March 2008, the overall storage of water for Hydro was 20.5 per cent

http://www.media.tas.gov.au/release.php?id=23180

And inflows for January were actually negative. That is, less than the loss due to evaporation so no actual inflow at all.

And the forecast for the next 7 days is, wait for it... fine, fine, fine, fine, fine, fine and fine.

 

[Prospector]

Or into Adelaide! We have not had any rain for 6 weeks; the temperatures since last Monday have been between 35 - 39 degrees, and it will be another WEEK of 35 - 39 degrees. The longest heat wave ever recorded in Adelaide.

 

[Smurf1976]

So is there anywhere getting the right amount of rain? Seems to be either floods or extreme drought across the country at the moment.

 

[noirua]

This appears to be the answer: http://www.wizard.gen.nz/raindance.html

 

[The Once-ler]

So is there anywhere getting the right amount of rain? Seems to be either floods or extreme drought across the country at the moment.

Northern NSW and southern QLD has had a perfect summer. No floods [excepting coastal areas] like further north, but just good rain all summer. Plus much cooler than average.

The dryland summer crops, mainly grain sorghum, will be a record yield and tonnage.



That figures too I suppose. This area is in between the wet north and the dry south.