Evaporation Prevention Using Molecular Blankets

Makarand writes "According to this article in the New Scientist, a Canadian company is testing a technology to reduce water evaporation from reservoirs by spreading an ultra-thin blanket of organic molecules on the surface to block the escape of water molecules into the air. Trials conducted in India and Morocco showed between 30 and 45 per cent reduction in evaporation using this method. However, the long term ecological effects of reducing evaporation in lakes or reservoirs is not yet clear as evaporation prevention can increase water temperatures and affect the exchange rates of gases such as oxygen, nitrogen and carbon dioxide."

Comments

Hey...

[hazman]

That's not a environment destroying oil spill, its a high tech water evaporation prevention film.

Weather too

[BWJones]

However, the long term ecological effects of reducing evaporation in lakes or reservoirs is not yet clear as evaporation prevention can increase water temperatures and affect the exchange rates of gases such as oxygen, nitrogen and carbon dioxide."

Don't forget possible changes to the weather. For instance, there are a number of areas whose climate and micro-climate are influenced by nearby bodies of water.

Re:Weather too

[TheLink]

While the film reduces evaporation, I doubt it reduces aerosolization significantly.

Still, as long as its your crap or someone close to you (family) it shouldn't matter that much in most cases.

Coz either the germs are yours or you're going to get them from other routes anyway. e.g. if you and your family are healthy, then small amount of aerosolized germs are unlikely to kill you - your immune systems already know how to deal with em. However your germs may kill/sicken strangers, and theirs might do the same to you.

doesn't this happen naturally?

[goombah99]

No natural body of water has wter on the surface. its all coated by oily or other hydrophobic molecules lighter than water. I guess I dont understand what they are proposing to do differently. do their molecules cross link to each other forming an actual blanket that is kinetically impermeable at natural temperatures.

I would think that if water cant get out kinetically then air and nitrogen cant get in. so you can kiss all fish and algea goodbye.

Need more research

[whereiswaldo]

However, the long term ecological effects of reducing evaporation in lakes or reservoirs is not yet clear as evaporation prevention can increase water temperatures and affect the exchange rates of gases such as oxygen, nitrogen and carbon dioxide.

This seems like a pretty critical area of the research. If the water becomes stagnant and full of algae or dead fish, what good is it?

This could have unforeseen effects on the local ecosystem.

Unforseen? Maybe if you have your eyes and ears taped shut? Forgive me for being cynical, but it seems so many scientists are out for a little fame and don't see the big pictures.

Re:Need more research

[Daniel Dvorkin]

in my experience, most scientists are much, much more interested in being right, it's an ego thing.

And your experience is?

I'm sorry, I have to ask this. Working in biotech as I do, I deal with scientists on a daily basis. (I'd like to call myself one, but honesty won't allow me to do so until I get my PhD.) In my experience, they're human like anyone else -- and like anyone else, of course they'd prefer to be right than wrong; but the nature of the profession is that it ultimately rewards those who check their data carefully and accurately forecast the consequences of their actions, and punishes those who don't.

The idea that scientists are egotists who refuse to acknowledge their failings is a vile stereotype, with no more basis in fact than the idea that they're cold and unfeeling, or sexless geeks, or unable to appreciate art and culture, or ... well, you get the idea. So you'll understand if I have my doubts that such a slur comes from someone with much real experience of science and scientists at all. If I'm wrong, please let me know.

Can anyone say "Breaking the Cycle"?

[atgrim]

Call me silly... but, isn't water evaporation part of the cycle of weather? Take out one part and the machine doesn't work. I hope that this "technology" is not used on a large scale. The implications concerning local weather patterns could be devastating.

this is a BAD idea

[c4ffeine]

Last time I checked, something called "rain" is made possible by evaporation from lakes, resiorvoirs, etc. Wouldn't preventing evaporation prevent rain? Rain happens to be a great way to irrigate fields, and is very good for our environment...

Positive spin?

[gerardrj]

...by spreading an ultra-thin blanket of organic molecules on the surface to block the escape of water molecules...

Are they trying to place a positive ecological spin on oil spils/slicks? Oil is organic, and it does prevent the evaporation of the underlying water.
I recall seeing/reading elsewhere that a few millileters is enough to create a minute slick over several square kilometers.

Old hat

[njh]

We studied this in school. They use large alcohols as the skin (as covered in this article). The point is that it's usually distribution rather than storage that is the problem. (In Melbourne.au the annual evaporation rate is 3m - on a shallow 30m deep dam this means that it would take 10 years to evaporate the water away, assuming none is added. I have some old papers here from the 60s by the then Melbourne Metropolitan Board of Works about this idea.

If you are having problems keeping water due to evaporation then you need to choose a better dam site.

More interesting is a proposal to store stormwater underground. Firstly, the land area and evaporation issues disappear (to be replaced by similar issues :) but more importantly, the water is actually cleaned by the action of anerobic bacteria on the water.

Website URL and Possible Additional Application

[pipingguy]

Flexible Solutions

This might also be useful for refineries/chemical plants, etc. that maintain large atmospheric pressure reservoirs of dihydrogen monoxide for fire-fighting purposes.

Everything gets run through the green filter?

[TheNarrator]

It's kind of annoying that these days, when any new technology arrives, it is subject to a ridiculously paranoid environmentalism filter. Resevoir water is about .0001% of all water on the planet and people are worried about gas exchange and the temperature of it! Enough to deprive populations in the developing world of clean drinking water? I was suprised that the cost of the system wasn't mentioned in the header, only the environmental impact.

J G Ballard's "The Drought"

[Dynamoo]

This is *exactly* the basis for the plot in J G Ballard's bleak vision of the future, "The Drought" where the oceans become covered in a thin molecular film which prevents evaporation of the seas, and hence no rain.

In the book the film is caused by pollution, but it is almost impossible to disperse and remains resistant to the waves and man-made attempts to break up the film. In the end, humanity ends up clinging to life by the edges of the ocean, each person with their own solar-powered desalination plant.

A sobering thought if you've read the book. Imaging what whould happen if this stuff got loose?