the internet has ruined me worse…isn’t bromate what one frat guy does to the other after he bromoforms him to get into the ozone? 
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The result is quite intriguing from a Materials Science standpoint!
http://www.allenjhall.com/content/2008/06/14/worlds-largest-materials-science-demo/
Black plastics absorb heat
Heat is bad for plastics in terms of leaching. Who’s idea is this? They fired yet?
“People”, in this case, would include the LADWP. They had to dump the contents of the Silver Lake and Elysian reservoirs due to bromate contamination back in 2007. In 2008 they covered the Elysian Reservoir and the Ivanhoe Reservoir (a smaller reservoir just above Silver Lake) in shade balls. Silver Lake has been replaced by the first of the new Headworks Tanks, and the second, now under construction, will allow Ivanhoe to be taken out of service as well…
And, yes, they have some hard science on the results.
The primary purpose of the balls is to provide shade to prevent the sunlight-driven reactions that create bromate. The black color blocks all light, including UV.
The reduction in evaporation is a (relatively small) bonus - as is the reduction in waterbird-generated pollution. It did make for a good soundbite at the mayor’s photo-op, though, what with the drought and all.
The Van Norman Reservoir, subject of today’s announcement, is the terminal reservoir of the LA Aqueduct, as well as the intake point for purchased SWP water from the Jensen Filtration Plant next door. Sitting at the high point of the San Fernando Valley, the Van Norman Reservoir serves, in effect, as the “municipal water tower” for LA’s mostly gravity-driven delivery system.
They really don’t want to have to dump it because of bromate contamination.
(A new UV disinfection plant for Aqueduct water is being built. Changing the primary disinfectant from ozone to UV will greatly reduce the potential for bromate formation.)
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The really kewl thing is that the floating balls can be used to illustrate how grain boundaries work in polycrystalline materials.
This, f’rex, is the Elysian Park Reservoir:
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Now if they only had water to go with the balls…
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Those words mean nothing to me but that picture looks really kewl!
Care to explain a bit or point me to a relevant Wikipedia page?
Edit: This page, linked earlier and already opened in a new tab, seems to be doing the job:
http://www.allenjhall.com/content/2008/06/14/worlds-largest-materials-science-demo/
If a person (or animal) falls into a reservoir covered in balls, would they still be able to swim in it, or would they be trapped under the balls?
HDPE is (pretty much) completely recyclable too.
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You misunderstood my comment; I was talking just about the science behind using balls to prevent evaporation, and while I’m sure there is some science there, as I said a brief search didn’t produce any hard numbers for me.
Governments are regularly fleeced in this manner. It’s a result of electing people who demand they have a background in business that qualifies them for governance, because they do.
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Also, all of those balls are floating, so they must weigh the same as a duck… THEY’RE PUTTING MILLIONS OF TINY WITCHES INTO THE WATER SUPPLY! BURN THEM!
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From the Silver Lake Reservoirs Conservancy news letter, back when Ivanhoe Reservoir just above Silver Lake was being covered:
The reason LADWP is using the bird balls is because they are the ONLY National Sanitation Foundation (NSF) drinking-water-approved product of its kind on the market. When we discuss NSF approval, it means that this product has been tested precisely to ensure that it does not create the kinds of problems that some are insisting they create. The balls are made of High Density Polyethylene – a long-time water industry product also used for pipelines, and a black version of the same clear product you buy your one gallon container of milk in (look on the bottom for the HDPE label). You will not find any legitimate news findings claiming that HDPE leaches chemicals into drinking water.
The ‘bird balls’ were originally used to keep waterbirds from frequenting shallow ponds near airports, so as to reduce bird strikes. I believe their use was suggested by Dr. Brian White, an LADWP research biologist. And no, he was not fired, though he did subsequently retire.
But I’ll be sure to let the folks at the DWP know that Internet Experts among the Boingboing commenters disapprove, because leaching.
<Fe> I’m sure they’ll be thrilled. </Fe>
A couple of relevant links:
http://www.latimes.com/local/california/la-me-silver-lake-reservoir-20150615-story.html
http://www.plasticsnews.com/article/20140103/NEWS/140109973/plastic-balls-protect-california-reservoirs
For inquiring minds, and such…
Not sure why they have navels. Or why they were colored black for that matter. All you need for shadow is something opaque but black is also going to heat up the water and increase evaporation rate.
Not sure about what you mean by “navels” but it may be a mould sprue.
The black coloring is because carbon black is a good antioxidant and UV protection for plastics. If you want a plastic for outdoor use, the black ones tend to last longer.
Not when it has to cover 175 acres.
Ah! Makes sense.
Elsewhere, I read they are partially filled with water. Not sure why. Maybe to make them float lower and improve the packing. The navel is probably a plug.
Whatever, somebody really missed an opportunity to call out the Dodgers and whip a few in with whiffle bats. Being water filled, it probably flies like a knuckle ball.
All the major news reports I saw said the reason for the balls was to prevent evaporation. In a throwaway line, one mentioned it also helped prevent “contamination” (with no mention of bromate).
Also, I wonder why the balls are jet black; wouldn’t a lighter color, any color, be better for reflecting light and not retaining heat?
