"The key is to keep these balls clean..."

Update on L.A.'s balls:

The benefits are clear, Professor Pradhanang insists, as Los Angeles strives to retain as much water as possible amid the drought. Like other urban cities, such as New York, they also face a constant battle to keep wildlife off the clean water reservoirs, as their feces is the real source of bacteria.

And, though the truck-load of balls cost $34.5 million, it is easily a much cheaper alternative to covering the site in tarps.

But any color would have been better than black.

'As we know, black absorbs heat. So that won't help the thermal blanket,' remarks Professor Pradhanang. 'The key is to keep these balls clean - but that will be a monumental task.' 

via www.dailymail.co.uk