Reservoirs Cause rainfall

Scientists have found that large bodies of water can make it more likely to rain.

http://www.bbc.co.uk/news/science-environment-20663875

So if that's true, and it makes sense to me that it could be, then that could mean that once an area has flooded, it is theoretically more likely to flood more.

I still think the solution is to grow more trees.

 

More trees is always good

Watched a prog last week where the presenter had a bucket of water to represent all the water on Earth. He said most of it is salty, then he cupped his hands to represent the 3% that was fresh water, saying most of that is locked up in ice.

He let the water go, saying the total amount of drinking water that is available to us is represented by the water still clinging to his wet hands

 

So conversely, a long term drought afflicted area isn't likely to be flooded in the near future?

How much are we paying these 'scientists'? Are they getting their information from the 'Daily Express'?

 

Now you mention it, that's exactly what's happened in Lanzagrotty. When it blew up a couple of hundred years or so ago, it wiped out all the vegetation. Now it hardly ever rains there.

 

Mrs Scrungee has told me that this thread title should be titled "Reservoirs effect rainfall", because affect is noun, not a verb and her being an English Graduate (and a pedant) got so incensed about this grammatical crime she insists it should be corrected.

 

Well I'm in no position to challenge Mrs Scrungee, as the best I can offer in terms of English qualifications is GCSE grade C. However, I always thought that an 'effect' was a consequence of something, where as something could be 'affected' by something.

 

affect is a verb
effect is a noun

 

Just googled it now (to make sure I was right)

http://grammar.quickanddirtytips.com/affect-versus-effect.aspx

That's it in normal usage.
But "to accomplish" is "to effect".
An "affect" as a descriptive noun is a noun.
(just to confuse you even more.)
But most times "affect" is a verb and "effect" is a noun.

 

The effect of this thread has affected me.
So, all I can say is, most inland bodies of water are surely too small to have any real effect on the weather, its only when you have massive lakes, like in other parts of the world, that they come in to play climate wise.

Deforestation is, I think, a different proposition which again mainly affects large land masses.

 

Trees help to regulate the the amount of ground water. They mop up water (to some extent) when it is available and release it back into the air as they respire through their leaves. When the ground is dry, the tree becomes much less active and goes into a sort of survival mode, not releasing water vapour into the air, but all the while sheltering the ground from sunshine and to some extent, the wind. Anyone who's done the standard prank of jumping up and shaking a tree branch after a rain shower, just as their missus walks under it, will know that tree crowns also produce a lot of surface area to hold onto a fair amount of water that fell on it as rain. Its why rain is reliable as clockwork over rain forests, and why the rainforest floor never dries out. Ok, a few thousand trees doesn't make a rain forest, but they can mop up a lot of water, and I reckon reduce (even if only marginally) the risk or severity of flash floods such as we've seen just lately.

 

Too right, the stomata in the leaves close in the heat of the day to stop water loss, thats when photosynthesis stops as the CO2 in the leaves gets used up. So thats a lot of water being held that would evaporate without the trees.

 

I dont think trees will ever reduce flash floods, they are by nature surface run off, that takes place before the ground can absorb the rainfall.
They will never stop winter floods either, as most dont absorb much in the winter.

Building and the concreting over of large areas can have an effect, but recently the ground has been saturated in some areas by sheer rainfall amounts.

Its just rained a lot.

 

True, but I'm sure you've sheltered from a sudden rain shower under the canopy of a tree before. The trees slow down the rate at which the rain water reaches the ground. Ok, not indefinitely, but tree tops will snag a lot of rain water before they reach 'capacity' and stop offering any resistance.

 

Have you ever stood at the edge of the trees canopy during a down pour.
Trees shed the water further out, but most trees, (in this country), are leafless in winter so that effect does not happen.

If the shower is small enough to be able to shelter under a tree its unlikely for the rainfall to be heavy enough to cause a flash flood.

 

There is another very important effect of trees in relation to flooding, which is the large amount of woody debris (including large branches and whole trees) that naturally falls into rivers, streams etc. and obstructs the flow. This causes more local flooding in upstream areas following heavy rain, but the flow of water downstream is slowed considerably by the large volumes of water stored behind debris dams and on associated floodplains.

In Britain, though, since we've both deforested river catchments and cleared most of the woody debris out of rivers, the natural water storage capacity of our rivers is greatly reduced. So rain falling in the uplands doesn't stay there long, but very quickly rushes downstream and floods houses etc. in the lowlands. Conversely, when there's a drought, river levels fall very low because there's little stored water upstream to maintain a more even flow throughout the year.

There was an interesting Radio 4 programme on this earlier this year - available on iplayer here:
(plus lots more info online if you search for it)