This story seems to almost be out of science fiction (or The Prisoner) but the pictures don't lie. The water people in Los Angeles are so desperate to save what water is left in some reservoirs that they are essentially putting a roof on it by filling the lakes with black plastic balls:
Facing a long-term water crisis, officials concerned with preserving a reservoir in Los Angeles hatched a plan: They would combat four years of drought with 96 million plastic balls.
On Monday, Mayor Eric Garcetti of Los Angeles arrived at the 175-acre Los Angeles Reservoir to release the final installment of the project: 20,000 small black orbs that would float atop the water. [...]
Mr. Garcetti said that the dark balls would help block sunlight and UV rays that promote algae growth, which would help keep the city's drinking water safe. Officials also said the balls would help slow the rate of evaporation, which drains the water supply of about 300 million gallons a year. The balls cost $0.36 each and are part of a $34.5 million initiative to protect the water supply.
This is an ingenious way of reducing evaporation. Perhaps the state's aqueduct system can also be filled with these balls to stop evaporation there.
HughPickens.com also submitted this article just minutes later!
(Score: 3, Insightful) by jimshatt on Thursday August 13 2015, @06:58AM
(Score: 0) by Anonymous Coward on Thursday August 13 2015, @07:11AM
Well, black is better at blocking and white at reflecting.
So hindering algae growth might be more important than the extra evaporation.(Extra compared to hypothetical white balls. Still better than no balls. )
(Score: 5, Interesting) by Anonymous Coward on Thursday August 13 2015, @07:13AM
White balls will break down more readily from UV exposure. The black balls contain carbon that absorbs heat but prevents breakdown. Some plastics will break down very quickly in the sun. For example, white wire ties are not UV rated while black ones are.
I suppose it's a tradeoff - more heat vs replacing the balls frequently and cleaning up the bits of degraded white plastic.
(Score: 2) by mcgrew on Thursday August 13 2015, @12:58PM
Thank you, AC, I'd been wondering the same thing.
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(Score: 0) by Anonymous Coward on Thursday August 13 2015, @07:15AM
Black balls are bigger. Everybody knows that.
Haven't quite figured out how to make them both AC and DC powered .
(Score: 0) by Anonymous Coward on Thursday August 13 2015, @12:43PM
i suppose if the blackballs are very tightly packed then "maybe" they will help with evaporation loses.
however if there are gaps then blackballs will hasten the evaporation because they become hot quicker (absorbe)
and then, because of the the gaps, a bit of wind (will happen because black surface is hotter then surrounding) will "turn" the balls, exposing the wet underside to the top air and .. voila ... evaporation and as a side effect ... cool blackballs : )
i would have gone with titanium dioxide (nano sounds cool?) painted balls ... or maybe just plain old styrofoam?
(Score: 4, Interesting) by karmawhore on Thursday August 13 2015, @02:06PM
=kw= lurkin' to please