There are some things that, at first glance, seem so absurd that you have to wonder why it was being done. Many are quick to point out even if something looks stupid, but it works, then it isn’t stupid. Indeed that’s what I first thought when I heard that Los Angeles Department of Water and Power was filling up their water reservoirs with millions upon millions of plastic balls as it sounded like some form of a joke. As it turns out it’s anything but and compared to other solutions to the problem it’s actually quite an ingenious project (not to mention how soothing dumping that many balls out of a truck sounds):
The first thing that comes to mind is why use millions of plastic balls instead of say, a giant shade structure to cover the resevoir? As it turns out constructing something like that would be an order of magnitude more expensive, on the order of $300 million compared to the total project cost of the shade balls of approximately $34 million. The balls themselves will last approximately 10 years before they start degrading at which point they’ll likely start splitting in half. Putting that in perspective you’d need the shade structure to last almost 100 years before it would be a better option than the balls, a pretty staggering statistic.
The balls provide numerous benefits, the largest of which is the reduction of water lost to evaporation in the reservoirs. The current reservoirs, which stretch over some 175 acres, hold about 3.3 billion gallons of water and about 10% of that is lost every year to evaporation. These little balls will then save some 300 million gallons of water a year from being lost. Additionally chemicals such as chlorine and bromide can combine into bromate (a potential carcinogen) under sunlight, something which these little plastic balls will help prevent.
In all honesty when I first saw this I thought it was a joke, a viral video that was advertising a plastic company or something equally as banal. However digging further into it the science of it is sound, the cost is far cheaper than the alternatives and the benefits of doing it outweigh the costs.
Colour me impressed.