LA is dumping millions of plastic balls into its reservoir to tackle the drought

They&#x27;re not dumping plastic balls in order to tackle the drought, they&#x27;re being dumped because the EPA mandated that all reservoirs be covered. Direct sunlight will cause bromide and chlorine in the water to mix into bromate, a known carcinogen, and the EPA wants to prevent buildup of this compound in the drinking water supply. Covering the reservoir with a tarp is too expensive (costing over $300 million) and plastic balls are a much cheaper option. The evaporation reduction is a secondary benefit, not the primary one, and the article title should reflect this.<p>There&#x27;s much better coverage of this story here [1] and here [2].<p>[1] <a href="http:&#x2F;&#x2F;www.npr.org&#x2F;sections&#x2F;thetwo-way&#x2F;2015&#x2F;08&#x2F;11&#x2F;431670483&#x2F;la-rolls-out-water-saving-shade-balls" rel="nofollow">http:&#x2F;&#x2F;www.npr.org&#x2F;sections&#x2F;thetwo-way&#x2F;2015&#x2F;08&#x2F;11&#x2F;431670483&#x2F;...</a><p>[2] <a href="http:&#x2F;&#x2F;news.nationalgeographic.com&#x2F;2015&#x2F;08&#x2F;150812-shade-balls-los-angeles-California-drought-water-environment&#x2F;" rel="nofollow">http:&#x2F;&#x2F;news.nationalgeographic.com&#x2F;2015&#x2F;08&#x2F;150812-shade-ball...</a>

This may seem like a silly question, but...<p>Why on earth are you chlorinating the water <i>in the reservoir</i>? I&#x27;ve never seen any other country that does that. Isn&#x27;t it a really, really terrible idea? Environmentally ghastly because you kill everything in the reservoir, expensive due to chlorine loss, subject to side effects (like this one), and ideally suited to breeding chlorine-resistant bacteria... not to mention giving you nigh-undrinkable water!<p>I&#x27;m from the UK, and we chlorinate our water pretty heavily, but even we don&#x27;t do this.<p>(I now live in Switzerland. Water in Zürich is purified via activated carbon, live biofilm and ozonation. The water which comes out of the tap is unchlorinated and is better and more drinkable than most bottled mineral water.)

I think the story sounds a bit ironic:<p>So you are essentially dumping objects made out of chemicals, you had to drill wholes in the ocean ground to get, into a lake, because you found out that the chemicals you dumped into it earlier kill you when the sun shines on them. You also think that this might help you with the water shortage caused by unsustainable use of resources.<p>To me this all sounds like we arrived at a local maximum here. This simply cannot be the way to do this. Maybe we should start over.

I wouldn&#x27;t be surprised if the balls increased the evaporation rate, for the simple reason that it will increase the surface area of the water (the balls will rotate in the water, bringing wet surfaces up). Black balls will also heat up more, causing more evaporation.

What I don&#x27;t understand is that they dumped black balls in the reservoir. If you want to keep the water cool to lessen evaporation wouldn&#x27;t it make sense to use white or reflecting balls so the water stays slightly cooler?<p>I would be glad to know why black balls are chosen.

Looks like 3d simulation example came to life :)<p>But seriously, why balls are used? They say it&#x27;s cheap but 36 cents doesn&#x27;t look too cheap on the hundreds of millions scale. Wouldn&#x27;t it be better to use sheet-like form? It will be covering space more efficiently.

I wonder if floating solar PV was considered as an alternative&#x2F;complementary solution that might pay for itself over time:<p><a href="http:&#x2F;&#x2F;www.eastgreenenergy.co.uk&#x2F;for-business&#x2F;products&#x2F;floating-solar-pv&#x2F;" rel="nofollow">http:&#x2F;&#x2F;www.eastgreenenergy.co.uk&#x2F;for-business&#x2F;products&#x2F;float...</a>

Do they really need to invent that much? It&#x27;s true that the current situation is maybe the worst they ever faced. But there are a lot of places where water is even more valuable as a resource. Are they also looking into what people in the desert do to keep their water sources alive, etc?

This chlorine everywhere in the US astonishes me. When visiting I&#x27;m not able to drink (non bottled) Coke b&#x2F;c of the bad and intense chlorine taste.

&quot;in which a total of 96 million balls have been poured&quot;<p>&quot;they&#x27;re cheap (costing just 36 cents per unit)&quot;<p>Is that really cheap, or is it just because it&#x27;s in LA?

The article title is misleading. If we assume water price of $1000&#x2F;acre-foot, then they spending ~$30m today to save 10x$2m over the next ten years. Water Davis are clearly a by-product benefit (as the article states) and the balls are not being used to tackle drought.

10 Year lifetime? Just the lifespan of these plastic balls being beaten with sunlight?

<a href="http:&#x2F;&#x2F;imgur.com&#x2F;JagJndf" rel="nofollow">http:&#x2F;&#x2F;imgur.com&#x2F;JagJndf</a>