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

Good idea. I saw a similar idea used by the Artis Zoo when I visited the fish facilities back in 2010. There, the floating balls were made of polystyrene, and they were used to insulate from heat loss.

http://www.sciencealert.com/la-is-dumping-millions-of-small-plastic-balls-into-its-reservoir-to-tackle-the-drought

 
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Yours sincerely,

Dr Richmond Loh 

DipProjMgt, BSc, BVMS, MPhil (Pathology), MANZCVS (Aquatics& Pathobiology), CertAqV, NATA Signatory.
THE FISH VET, Perth, Western Australia, AUSTRALIA. 

Mobile Aquatic Veterinary Medical & Diagnostic Services.
http://www.thefishvet.com.au
Ph: +61 (0)421 822 383