More about the reservoir balls - and a video

So, a layer of black plastic balls on the Ivanhoe Reservoir in Silver Lake. How, why, and for how long - the details about bird balls from Francisco Vara-Orta.

We've had lots of comments on this post and many of them included links. We can't publish URLs in comments (complicated legal reasons) so I'm posting the ones you sent - plus a few extras.

Bloggers who've been following the reservoir story include CSSLR, LA MetBlogs, Donna Barstow and Curbed LA. And for a corporate take on things, here's a manufacturer.

--Veronique de Turenne

Video: Brent Foster / Los Angeles TImes

Comments

[Donna Barstow]

I guess I was naive, to expect the LA Times and Mr. Vara-Orta would do more than post more pix and quote a DWP flackey.

The flow-through rate is so fast in Ivanhoe that every gallon is fresh each new day, as the water is piped to homes. This information is readily available in pdf form on their website. There's no time for bromate to form in one day! The low rate of bromate in Ivanhoe reflects that. It's Silver Lake where the water sits for much longer, although they can't use balls in a reservoir that big, partly because the factory making this non-recyclable plastic can't make the balls fast enough even for Ivanhoe, which is why they're dumping a few bags at a time.

In addition, we need available water in Silver Lake for emergencies, such as earthquakes and the Griffith Park fire. As I explain in my blog, they got almost all the water for that 4 day fire from Silver Lake. They'll never be able to use Ivanhoe water for any fires now: HDPE is highly flammable.

This whole exercise of buying millions of dollars worth of plastic balls made with crude oil is so DWP can say, "See, we tried!"

[Ryan McCarthy]

With the recent news stories about polycarbonate plasctic containing harmful chemicals that slowly leach out of the plastic into water, this makes me wonder whether unexpected side effects like this were carefully considered before the decision was made to use the plastic balls. Specifically, I hope that these questions were answered before they decided to use the plastic balls:

1) What is the photodegredation rate of the plastic, and what breakdown products can be released into the water as UV light breaks apart the polymer?

2) HDPE plastic is inherently white--think milk jugs--so what is the black pigment used, is it non-toxic, and at what rate will it be released into the water?

3) What are the unexpected consequences of the water warming from the black plastic heating up in sunlight? Specifically, how will this affect the rate that chlorine evaporates out of the water? Will increased water temperatures, loss of chlorination, and a large unlit surface area on the underside of the balls lead to growth of harmful bacteria?

I'm not suggesting that any of these things are cause for concern, unless the decision makers didn't consider them before using the plastic balls. It's always the unexpected consequences that are the most harmful.

[David N]

The brain trust at DWP and Council have scored once again.
Sustainability - oops, the balls aren't recyclable
Human Health - oops, guess they haven't read about the linkage between sun-exposed platics and carcinogens
Wildlife - oops, the balls interfere with wildlife using the reservoir

Nice job.....

[JCFox]

Will this slow down the normal process of evaporation, and thus serve to conserve water too?

[Adam]

Stupid people...why not cover it with a sheet?

[Terry Johnson]

These balls are known to leach hazardous chemicals into the water and require National Science Foundation (NSF) certification PRIOR to installing on drinking water impoundments. The City of Los Angeles should ensure the people of Los Angeles that they have obtained NSF certification for this product to make sure that the water is safe with this cover system.

[David A. Smith]

Some answers for questions above:
- these plastics are used many places in municipal and bottled drinking water systems.
- bromate forms in the presence of sunlight in a matter of minutes, not days. It is reasonable to expect *some* reduction from covering this reservoir, if for no other reason than bromate naturally decays over time.
- evaporation is reduced by covering it. So some water will be conserved.
- from the air, most reservoirs are already essentially "black", so any incident light is absorbed by the water in the first couple of feet of depth. The balls simply provide a heated surface, that limits heat transfer via radiation, convection, or evaporation. Expect stratification.
- the black coloration is possibly carbon black, such as is used in treating drinking water, and (for example) tires.
- these balls are recyclable as, I believe, a /2\.
- not all pastics form "bad things" when exposed to sunlight. HDPE is the "safest", if that makes any difference.

Keep in mind that open reservoirs for drinking water are "verboten", a really bad idea, and are not permitted in new systems. Only fully enclosed drinking water reservoirs are now permitted. This is supposed to be a temporary band-aid until these reservoirs are brought up to "code", by conversion to some form of tank.

[Michael Clark]

Where did the video go? It's "unavailable." Maybe it should be on YouTube, a popular up and coming video service that's been in the press lately.

[John]

Interesting, first question that came to mind though...

What happens the first day there is a storm with some wind?

[Ken Nickless]

Are there any fish in the reservoir? If so would they not be affected/?

[Jonathan Weston]

The brain trust at DWP and Council have scored once again.
Sustainability - oops, the balls aren't recyclable
Human Health - oops, guess they haven't read about the linkage between sun-exposed platics and carcinogens
Wildlife - oops, the balls interfere with wildlife using the reservoir
It's incredible - whose bright idea was this - seems like they balls it up again!

Please someone tell me what we can do - we are the ones paying for this!

[Jonathan Weston]

In answer to David Smith - Do you work for the DWP - I think many of us would like to see these statements as checkable facts - 'keep in mind that open reservoirs for drinking water are "verboten", a really bad idea, and are not permitted in new systems. Only fully enclosed drinking water reservoirs are now permitted. This is supposed to be a temporary band-aid until these reservoirs are brought up to "code", by conversion to some form of tank"
The answer which would satisfy both residents and DWP is a tank system with an ornamental lake - water feature above - landscaped with a park which is open free to residents and to visitors with a fee - rather than a concrete basin surrounded by a ten foot fence - so how do we do it?