Worst drought ever

[Smurf1976]

"Date 11/12/2006
Author Rod Myer
Source The Age -- Page: B3
The drought is starting to affect the power generating capacity of south-east Australia's hydroelectric power scheme. Snowy Hydro has revealed that dam storage levels have declined to a record low of 17%. River inflows over the past year have been only 25% of the long-term average, although the company does not currently foresee any issues in meeting its commitments in the national power market. AGL Energy, which owns Southern Hydro, has noted that water levels in the Dartmouth and Eildon reservoirs have been affected by the drought, which in turn will have a negative effect on generating capacity, although its contracts are protected by hedging arrangements."

Any tips on companies that might benefit greatly from supply of bulk quantities of candles?

AJ

I can't help with the candles, but a few points:

Dartmouth has lost about one third of its generating capacity due to the reduction in head (water level). That is, it now generates 100 MW (and is doing so flat out) instead of 150 MW.

The Snowy Hydro system hasn't really lost any significant peak generating capacity (peak capacity is 3740 MW) but average output is way down and there is more use of pumped storage (Tumut 3 power station).

In the mainland states, hydro-electricity is a major source of peak generating capacity but coal generates most of the actual electrical energy used with gas taking up almost all of the non-coal or hydro balance (bit of wind, tiny bit of oil is the rest).

So, all it means doing is not running the hydro plants at times if intermediate demand for electricity but instead running them only when demand is highest. That way less water is used but the peak capacity is preserved. Dartmouth and Eildon are exceptions since the water is released primarily for irrigation with electricity only a by-product.

So, no blackouts but more coal and gas gets burnt.

Tasmania is an exception with its baseload hydro-electric system (average output twice that of the Snowy) which supplies virtually all power used in the state and has always done so. Inflows are seriously down as are storage levels (currently 31.3%). The Tasmanian system also supplies 600 MW of peak capacity to Victoria.

If the Tas system runs dry then the lights will go out in Tas and, if it gets hot enough, Victoria as well. But for some time now Tas has been importing about a third of its electricity from Victoria in addition to using gas for another 10% of generation locally in order to slow the fall in storage levels.

So outflows have been cut and the 31.3% storage isn't a serious problem. Most likely it will end up somewhere around 15% by next Winter - makes it difficult to balance water between the storages (since it can't be moved from one to another and there are 6 major and 1 minor catchment areas) but overall it's not a cause for panic. Just a lot of power imported from Victoria and a lot of coal and gas burnt to generate it.

So overall, the bottom line is the lights stay on for the moment at least but more coal gets burnt especially in NSW and also more gas especially in SA, Tas and Vic. If 2007 is a repeat of the weather of 2006 then we could be in trouble however.

 

[Kipp]

Interesting Smurf... an implication of the drought I hadn't previously considered
Like most city dwellers, it has taken me longer to feel its impact than in the bush. Till only recently, Melbourne always looked green, but introdcue stage 4 water restrictions and it might as well be Cunnamulla.

 

[The Once-ler]

Take it easy there mate, i'm postive about a lot of things...
there are plenty of crops suited to australian conditions, rice isn't one of them, neither is cotton. But whilst i can tolerate rice to some extent, Cotton and Grapes are both cash crops, and hence i don't consider them essential agriculture.

As i said in my post earlier if you bothered to read it, i agree that water flowing into the oceans is a waste... i'd rather they be stored in dams, aquifer's, whatever, for when the drought hits...

i am not blaming the rice farmers at present, becuase as things stand at the moment, there are not enough dams to store this water anyway.

the problem is infrastructure...
please read what i write before jumping around.

Yep, I'll go along with most of that.

But why aren't rice and cotton suited to Australia? OK, they need lots of water, so they are not suited in that aspect. But then Aussie farmers get very high yields out of these crops, as high as anywhere in the world. Mainly because of the hot dry conditions and the ability to turn on and off the water. In the agronomic regard, these crops are perfectly suited.

As for cotton not being essential agriculture? Why do you say that? I'll go along with grapes, but not cotton. I think you would be surprised at how much cotton is in every form of clothing. Cotton seed even ends up in oils of every form.

I agree with your other points.

It is great that Australia has such a diverse range of agriculture. We really don't have to import anything, and almost two thirds of what we grow is exported to help our shocking balance of trade. I would like to see cotton and rice continue to be grown and exported for these reasons.

Cheers.

 

[Smurf1976]

If the Tas system runs dry then the lights will go out in Tas and, if it gets hot enough, Victoria as well. But for some time now Tas has been importing about a third of its electricity from Victoria in addition to using gas for another 10% of generation locally in order to slow the fall in storage levels.

A point of clarification. Tasmania is importing electricity from Victoria during the 95% of the time when demand is moderate or low and there is surplus power available from coal or gas power stations in SA, Vic, NSW or Queensland. So the supply to Tasmania isn't leading to draining of water storages in the Snowy etc.

 

[skint]

Hi Rafa & Once-ler, You both seem to be advocating more dams, bigger dams and trapping as much water as possible. Sounds good until you consider the terrible effects of further depleting the environmental flows necessary to sustain the river systems. Water recycling, rain water tanks etc.. in the cities is a no-brainer. This water does flow out to sea with no benefit. West of the divide, the rivers are already at breaking point in non-drought times. We need to move to less water intensive practices and crops. Appropriate pricing, I believe, is the only way to make this transition. In 2006, the world is very slowly coming to realise that it only makes sense to work with rather than against the environment. Otherwise, worse droughts etc...
P.S. Spent some years on the land, so not just an "urban greenie".

 

[The Once-ler]

Hi Rafa & Once-ler, You both seem to be advocating more dams, bigger dams and trapping as much water as possible. Sounds good until you consider the terrible effects of further depleting the environmental flows necessary to sustain the river systems. Water recycling, rain water tanks etc.. in the cities is a no-brainer. ".

That's a fair comment. And I definately agree on the rain water tanks and recycling bit. I just can't believe city people let so much water run down the drain then try and figure out who they can get some more water off.

As far as the more and bigger dams bit goes, I don't think we have a choice in the long term. Remember that the dams mainly only collect flood water. The rivers now would be dry weather or not irrigation or dams were there. In fact there is generally an environmental flow allowance let go with a big irrigation flush, so one could argue that some rivers would have more water than they otherwise would get.

We are using more power. Therefore powerstations will need a guaranteed supply. Already irrigators have had allocations cut to zero in the Hunter, because the remaining water in Glenborn is needed for power generation for Bayswater and Lidell, which produce 40% of NSW power.

Have you checked grain prices lately? Food production has been hit by global warming. Crops were down last year all around the world. Grain production has been less than consumption for 6 of the last 7 years. Plus America is for some dumb reason turning 40 million tonnes of corn into ethanol.

I think we either cut back the human population [which ain't gunna happen] or we drop our standard of living, meat consumption, energy consumption, [which ain't gunna happen] or we need more and bigger dams.

That's just how I see it.

Cheers.

 

[Kipp]

I think we either cut back the human population [which ain't gunna happen]

Cheers.

Europe and NZ have both achieve 0 population growth so why can't we? I think we are at less than 2 births per woman so we probably would if it weren't for our pretty high immigration rates.

Environmentist Tim Flannery claims the sustainable population for Australia is 6-12 million. And it'd be a pretty safe bet every city in Australia wouldn't be on water restrictions if that was the case.

Anyway... this is a very unrealistic scenario. I was thinking about something else the other day though. How much drought can the native bush tolerate? Everyone has always considered the Eucalpts etc to be very hardy and drought resistant, but surely there is a point when it will all die off as well? (Particularly for seedlings) Is this possible?

 

[Smurf1976]

That's a fair comment. And I definately agree on the rain water tanks and recycling bit. I just can't believe city people let so much water run down the drain then try and figure out who they can get some more water off.

As far as the more and bigger dams bit goes, I don't think we have a choice in the long term. Remember that the dams mainly only collect flood water. The rivers now would be dry weather or not irrigation or dams were there. In fact there is generally an environmental flow allowance let go with a big irrigation flush, so one could argue that some rivers would have more water than they otherwise would get.

We are using more power. Therefore powerstations will need a guaranteed supply. Already irrigators have had allocations cut to zero in the Hunter, because the remaining water in Glenborn is needed for power generation for Bayswater and Lidell, which produce 40% of NSW power.

Have you checked grain prices lately? Food production has been hit by global warming. Crops were down last year all around the world. Grain production has been less than consumption for 6 of the last 7 years. Plus America is for some dumb reason turning 40 million tonnes of corn into ethanol.

I think we either cut back the human population [which ain't gunna happen] or we drop our standard of living, meat consumption, energy consumption, [which ain't gunna happen] or we need more and bigger dams.

That's just how I see it.

Cheers.

Dams are fundamentally a means of regulating the flow of a river or of providing a diverted, regulated flow taken from the river. Nothing more and nothing less.

Build the dam big enough and you get 100% regulation of outflows. Australia doesn't have too many dams like that - Great Lake in Tasmana being the largest storage relative to annual inflows (holds 5 years of inflows with 20% of that inflow itself being regulated by another dam which holds 4 years worth) as far as I am aware.

Elsewhere, the problem is that dams tend to overflow, or the water is unnecessarily let out, during floods thus failing to fully regulate the flow of the river. Due to smaller size, they also tend to run dry (or the outflow is reduced to avoid actually running out) during droughts.

Bottom line is if th dams are big enough then you do capture all of the available water whereas smaller dams don't do this.

The second point about dams is expectancy. If annual water release exceeds long term annual inflows then it will run dry eventually no matter how large the dam is. Likewise it will spill if outflows are less than inflows. A point that 99% of those commenting on water (in general, not referring to posts on ASF) fail to grasp.

You CAN drought proof a hydro-electric system and you CAN drought proof a water supply system if you get the storage capacity and inflow/outflow balance right. It is a fact that, for example, the hydro storages in Tasmania (currently at 31.3%) could easily be 70%+ full if there was a decent surplus of long term inflows over outflows which could be achieved by building another major dam. In that context the system could then sustain another 5 years of drought without a worry. It can be done but in all states it isn't being done for various mostly political and economic reasons. We just accept running out of water every few years - something we wouldn't accept with practically anything else.

I say "drought proof" in terms of probability. For example, you can reduce the chance of having ANY water restrictions of any kind to a 1 in 50 year event without losing too much as long as you build enough infrastructure. Most Australian water systems don't come anywhere near that standard and indeed nobody outside the hydro-electricity industry seems to even do the maths to know what the probability of failure for a system actually is. Most systems seem to have failure rates that just wouldn't be acceptable if they were actually properly calculated - but nobody knows for sure because it hasn't been worked out properly.

As for whether we should or shouldn't be building more dams, ultimately it is a question of population and economic growth GLOBALLY. Continue the notion of infinite growth in GDP or population and there's no alternative to more and more infrastructure to underpin that, dams included.

If we had today's water infrastructure 50 years ago then no drought ever known to have happened in this country would have caused the slightest problem with water supply for any use. Run the sprinklers flat out and it just wouldn't matter. But add in the growth of population and industry and the infrastructure just isn't adequate. Keep growing population etc and in due course sprinker bans become permanent and "water restrictions" come to mean no showers or washing hands for months on end. That is the factual reality of growing population without growing water supply infrastructure (noting that rainwater tanks and recycling systems are a form of water supply infrastructure and are just another source of supply which adds inflow to the overall system).

If global warming does reduce rainfall then we'll need more dams just to stay even with supply volume. Add in population growth and we're looking at some serious engineering works being necessary. At some point you just can't have infinite growth on a finite planet but that notion isn't yet widely accepted - hence building more water infrastructure is the only real alternative.

 

[The Once-ler]

How much drought can the native bush tolerate? Everyone has always considered the Eucalpts etc to be very hardy and drought resistant, but surely there is a point when it will all die off as well? (Particularly for seedlings) Is this possible?

I think the harder the drought, the more the natives will thrive. The harder the drought, the more the introduced species will suffer, the natives evolved in this harsh climate of drought and flooding rain [and sticking heat and frost and bushfire].

Don't worry about the native bush.

 

[Kipp]

I think the harder the drought, the more the natives will thrive. The harder the drought, the more the introduced species will suffer, the natives evolved in this harsh climate of drought and flooding rain [and sticking heat and frost and bushfire].

Don't worry about the native bush.

Ok... not to worries about Wattles and Gums. The rainforest ferns etc (Dandenongs, Cape Otway etc) need more water than most introduced species. So I think we'll still have bush, but where there once was ferns, mosses, etc we'll have banksias, weeds and shrubs in the landscape. But this is probably only shortterm (assuming rainfall recovers).

 

[Aussiejeff]

I can't help with the candles, but a few points:

Dartmouth has lost about one third of its generating capacity due to the reduction in head (water level). That is, it now generates 100 MW (and is doing so flat out) instead of 150 MW....

Today the Dartmouth generators were switched off. No more generation until the water level rises again (not much chance of that within next 6 months!). However, outflow to the Murray River via Lake Hume to remain at maximum level (about 10,500ML per day) until dam runs dry.

Current levels:

Dartmouth Dam at 30% - (16 weeks till dry at current outflow).
Hume Dam at 4.8% - (7 weeks at best till dry at current outflow).

I've already purchased a water distiller for all drinking water needs 'cos the water supply in Wodonga is getting a bit on the nose again... smells of chlorine/ammonia. It was bad enough last time Hume Dam got down to 6%. I wonder what water quality will be like with Hume Dam at 0% by mid Feb '07?

*Sigh*

Oh well, have a Happy New Year chaps..

Parched Aussiejeff

 

[Happy]

Possibly current immigration doesn’t help either, this year 130,000

Statistically every person uses 330 litres a day for personal use.

While ago we’ve had business migrants, who brought money.

Now we can have water migration, for those who can bring millions of litres of water.

 

[trading_rookie]

Anyone see that CSIRO scientitst on the news last night? Barrie Hunt - I think he was the one they were talking to on sunrise about the climate being cyclic.

Anyway, he mentioned that according to 10,000 year old CSIRO weather models droughts are not caused by global warming. He went further and mentioned that no one knows what causes them, when they'll arrive and for how long they'll remain.

 

[chops_a_must]

Anyone see that CSIRO scientitst on the news last night? Barrie Hunt - I think he was the one they were talking to on sunrise about the climate being cyclic.

Anyway, he mentioned that according to 10,000 year old CSIRO weather models droughts are not caused by global warming. He went further and mentioned that no one knows what causes them, when they'll arrive and for how long they'll remain.

That's in dispute.

There has been a study underway at Murdoch University for the last five years looking at why areas attract more rainfall than others, in Australia. There are many photos of cloud formations that literally just stop in the air, and wont move any further. You can see this along the rabbit proof fence, where on one side there are cloud formations, above vegetation, and on the other, where there are rabbits, there is nothing. This is the same where forrested areas have been cleared for farming, clouds stop over the forrest and are reluctant to move over the farming area.

So the conclusion becomes; that if there is moisture in the soil, there is something for clouds to form over, and something to draw rain down. And if farmers are to attract rainfall they are best off planting native Australian evergreens.

 

[Happy]

From ABC, December 29, 2006

MORE RAIN FORECAST AMID SIGNS EL NINO FADING


There are predictions Australia could return to a more normal rainfall pattern next year, with signs that the El Niño effect has peaked.

The head of the National Climate Centre, Michael Coughlan, says he is cautiously optimistic of a better chance of autumn rain.

"We will see some sort of a break in the autumn period," he said.
"Now whether or not it's a big enough break to recharge those very empty water storages, that remains to be seen."

He cautions that after the last El Niño ended in 2003, the subsequent rainfall was still lower than normal.
"It wasn't as strong as it has been in previous years, so we have to be a little bit circumspect about it," he said.

No worries, we can forget water debate and sleep easy, until next time.

 

[Smurf1976]

Today the Dartmouth generators were switched off. No more generation until the water level rises again (not much chance of that within next 6 months!). However, outflow to the Murray River via Lake Hume to remain at maximum level (about 10,500ML per day) until dam runs dry.

Current levels:

Dartmouth Dam at 30% - (16 weeks till dry at current outflow).
Hume Dam at 4.8% - (7 weeks at best till dry at current outflow).

Dartmouth power station ceased generation at 3:15 pm (daylight savings time) on 24th December.

The dam has two outlets. The upper outlet feeds the power station which has a rated output of 150MW when the dam is full. This outlet can not lower the dam below about 30% full and that level has now been reached due to intentionally letting as much water out as possible in recent times (to feed into Hume dam and then into the Murray).

That the dam can not be drawn down below 30% is a necessary design feature. You just can't have the outlet for a hydro scheme right at the bottom otherwise all sorts of rubbish ends up blocking the trash rack and being right at the bottom makes debris removal a problem. Alternatively, if you don't have a trash rack or some other screen then the rubbish goes through the turbines and pretty soon that ends in disaster.

For dams used only for hydro-electricity, they are considered empty when the water level is down to the intake level even though there is still water in the dam.

But for irrigation use there is a second outlet at Dartmouth which is effectively a means of draining the dam below the level at which the power station operates. This has now been opened so the level will continue to fall and the intake for the power station will be left literally high and dry relative to the water level.

Whether or not the loss of 150 MW generation from Dartmouth matters depends on what happens next. As long as nothing breaks down in Vic or SA, as long as we don't get a record heatwave, as long as Tasmania and the Snowy can both maintain full supply to Victoria during peak times (which in turn requires that not much goes wrong in NSW or Tas) then it should be OK. It's under 2% of Victorian peak demand and only 3% of average demand. But with supplies tight anyway it's possible that it could be the straw that breaks the grid's back if much more goes wrong. Short term though we're just burning more coal and gas to offset the loss.

 

[Aussiejeff]

Dartmouth power station ceased generation at 3:15 pm (daylight savings time) on 24th December.

The dam has two outlets. The upper outlet feeds the power station which has a rated output of 150MW when the dam is full. This outlet can not lower the dam below about 30% full and that level has now been reached due to intentionally letting as much water out as possible in recent times (to feed into Hume dam and then into the Murray).

That the dam can not be drawn down below 30% is a necessary design feature. You just can't have the outlet for a hydro scheme right at the bottom otherwise all sorts of rubbish ends up blocking the trash rack and being right at the bottom makes debris removal a problem. Alternatively, if you don't have a trash rack or some other screen then the rubbish goes through the turbines and pretty soon that ends in disaster.

For dams used only for hydro-electricity, they are considered empty when the water level is down to the intake level even though there is still water in the dam.
.....

Sounds a reasonable policy to me Smurf1976..

Do you know the cut-off points for the major Snowy Hydro Dams? (I presume the eastern states would be in mega-trouble if any - or god forbid - all of those were eventually tripped...)

Cheers,

Aussiejeff

 

[Smurf1976]

Sounds a reasonable policy to me Smurf1976..

Do you know the cut-off points for the major Snowy Hydro Dams? (I presume the eastern states would be in mega-trouble if any - or god forbid - all of those were eventually tripped...)

Cheers,

Aussiejeff

The way the Snowy scheme works is basically as follows.

It is a bit complex in terms of where the water flows end up but it is basically a single catchment scheme in that although water comes from various sources, most of it ends up going through Lake Eucumbene.

6 of the 7 power stations draw water either directly from lake Eucumbene or are reusing water from those that do. The exception is Guthega power station which is a small (60 MW) power station upstream of Lake Jindabyne (which itself flows into Lake Eucumbene) which is a "run of river" power station. That is, it has little storage capacity and it's output is basically a function of river flows at any given time.

Water from Lake Eucumbene is released in two directions. It can go through Murray 1 power station (950 MW), down the river and then through Murray 2 (550 MW) power station.

Other water is released from Lake Eucumbene into a small pondage from which it flows into Tumut 1 (320 MW) then Tumut 2 (280 MW) power stations and into another reservoir. From there it goes through Tumut 3 power station (1500 MW) and into another small pondage from which it is released into Blowering Reservoir (a substantial storage) and through Blowering power station (80 MW) into the Murrumbidgee River.

So the water either goes into the Murray or the Murrumbidgee and goes through a series of power stations to get there. It can NOT go through all the power stations - it is one way or the other even though it comes from the same storage lake.

All the power stations with the exception of Tumut 3 are natural flow. That is, water flows through and then goes down the river. Tumut 3 is natural flow with the ability to pump water from the downstream pondage back up into reservoir which feeds the power station at night using electricity generated from elsewhere (coal-fired plants in Vic or NSW). That said, it takes more than 3 hours to pump up hill what can run down hill on 1 hour so there are limits to this operation.

At present, Lake Eucumbene is roughly 15% full.

What happens next depends on how the scheme is operated. Most of the time electricity demand is less than maximum so not all power stations need to be running (since electricity itself can't in practice be stored).

If the Snowy power stations (except Tumut 3 in its pumped storage mode of operation) are only used when all other power stations (coal, gas etc) are running flat out then they won't be used very often. Consequently they will use very little water and the present amount in storage is more than enough. That is basically what's happening at the moment apart from Blowering being run in order to release water from its storage to keep the river flowing.

Depending on water availability, the Snowy generally sits somewhere in the middle. Typically, coal-fired plants run all the time, then the Snowy, then gas (twice the cost of coal) and finally oil (not that we have much oil-fired generation in Australia but there is a little bit).

The upside of the present operating strategy is it guarantees that water remains available to the power stations so they can run when needed (not just high demand but also if a coal-fired plant breaks down, for example). That ensures that the lights don't go out.

The downside is of course that the downstream flow is basically cut off. So far, this hasn't mattered since Blowering Reservoir is keeping the Murrumbidgee flowing whilst Dartmouth and Hume are keeping the Murray flowing. But a point comes (and is pretty near now in the case of Hume) where those storages run dry.

At that point it is a case of either let more water out of the Snowy than is necessary to meet power demand (by running the Snowy power stations more and some other power station (gas, coal) less). If that is done then the level in Lake Eucumbene could well drop rather quickly and that's when the threat occurs to power generation.

So, a conflict between security of electricity supply and keeping the rivers flowing if the drought continues. The electricity is easy as long as you don't worry about the irrigation demands downstream. Or vice versa if you aren't worried about power supplies next Winter. Doing both is the problem.

In that context it's worth noting that Dartmouth has at the moment twice as much water in storage as Lake Eucumbene so releasing more from the Snowy would only give a couple of months extra water for irrigation. But it could well result in blackouts next Winter (when demand is high) and also next Summer (when demand is even higher) if it doesn't rain.

Effects? NSW and Vic are in big trouble if the Snowy runs dry, especially with Dartmouth already gone (may as well add Hume power station to that too) and a power supply situation that was tight before any of this.

SA has a chance of a few problems in Summer but not the rest of the year.

Tasmania and SA could foreseeably come under pressure to "share the pain" and export power to Victoria at times when doing so would mean local shortages. That would mostly mean Summer afternoons for SA and Winter evenings for Tasmania since that is when those states have very high rates of power use coinciding with high rates of use in NSW and Victoria.

Queensland wouldn't have any problems but could well face pressure to maximise power supplies to NSW. That only becomes an issue if a plant or two breaks down in Queensland since they do have plenty of spare capacity at the moment (though running it is evaporating vast amounts of Brisbane's drinking water - potentially a major problem).

Another problem would be if any of the major coal-fired plants run out of water. We're even more dependent on them than usual (so more water used) at the moment due to the situation with the Snowy etc. I have no idea how they are going in terms of water supply (apart from the obvious ones using urban supplies) but they are truly massive water users so there may be an issue for some of them. Anybody know?

 

[trading_rookie]

Hey chops, I'm not suprised it is in dispute! Afterall, the scientific community is an egotistical one and they like nothing better than 'raining' on someone else's parade. I guess we'll just have to wait and see which one comes out swinging 'I told you so'.

This is the same where forrested areas have been cleared for farming, clouds stop over the forrest and are reluctant to move over the farming area.

So the conclusion becomes; that if there is moisture in the soil, there is something for clouds to form over, and something to draw rain down. And if farmers are to attract rainfall they are best off planting native Australian evergreens.

Not sure I agree with that. Farmers do the basics - they aerate, feed, and water the soil - it ensures crop, or feed for stock. In other words the soil should have enough moisture and nutrients to attract clouds/rain if that were the case.

Most farms have access to creeks, rivers and I think the issue is that overuse and daming of them has impacted on them. Look at the once mighty Murray and what the wine-producing districts have done to it.

Then there's places like Coffs Harbour that's symbolic with banana's yet it's not tropical enough to economically grow 'em. No wonder they can't compete with QLD. Smarter farming practise (from what I've read anyway) will see the farms move to blueberries or be sold off for coastal resorts.

 

[chops_a_must]

Not sure I agree with that. Farmers do the basics - they aerate, feed, and water the soil - it ensures crop, or feed for stock. In other words the soil should have enough moisture and nutrients to attract clouds/rain if that were the case.

Most farms have access to creeks, rivers and I think the issue is that overuse and daming of them has impacted on them. Look at the once mighty Murray and what the wine-producing districts have done to it.

No, it's pretty basic biology, just that farmers are surprised to hear it. There are reasons why sometimes forests are called rainforests.

The problem becomes, like we have now, not in normal years where moisture in the soil IS enough to draw rain down, but in times when everything has dried out so much so that there is no moisture in the ground drawing rain down. So it exaccerbates the problems of dry weather.