The Los Angeles Times reports that 20,000 black plastic balls have been added to the largest reservoir in L.A., the last of millions of "shade balls" meant to bring the city in line with federal water quality standards while helping preserve water in the midst of California's historic drought.
The balls, which have been in use in Los Angeles on a smaller scale since 2008, now cover all of the city's reservoirs, a gently-bobbing line of defense against harmful algae blooms and other chemical reactions brought on by direct sunlight, as well as a barrier to cut down on the loss of water due to evaporation.
The shade balls are made in California for about 36 cents apiece and are a source of pride for local officials, who characterized them as an innovative cost-saving measure. The city's mayor, who was on hand to throw in a few of the last balls himself, put out a press release to tout their track record during their last several years of use at L.A.'s three smaller reservoirs. From SkyNews:
[Los Angeles Department of Water and Power] general manager Marcie Edwards says the project is "a blend of how engineering really meets common sense."
Other solutions [for meeting federal water regulations] included splitting the reservoir and installing floating covers that would have cost $300 million.
She added: "We saved a lot of money. We did all the right things."
Mayor Eric Garcetti says the balls will conserve 300 million gallons of water that would otherwise evaporate every year.
He added: "While it's meeting the minimum standards, we want to go beyond that and have the healthiest water so we've been spreading these balls everywhere."
Prevented from blowing away by a small amount of water inside, the four-inch shade balls have a lifespan of approximately 10 years, after which they can be scooped up and recycled. Officials say that the balls are safe to have in the drinking water supply and will not leach chemicals into the reservoirs. The use of shade balls in Los Angeles was the brainchild of a now-retired biologist for LADWP, Brian White, who saw similar balls used to keep birds out of bodies of water near airports.
The last stage of shade ball deployment in L.A.'s reservoirs comes as California continues to struggle with the effects of prolonged drought. There have been few signs of improvement this year—the snowpack on the state's mountains had dwindled to virtually nothing as of April and the summer has brought an endless string of fast-moving wildfires in the parched landscape. Residents, meanwhile, have turned to "drought shaming" apps to report others seen as wasting water to keep their lawns green or their cars sparkling.
While 300 million gallons' worth of prevented evaporation is certainly useful for L.A., California's overall problem exists on a different scale entirely: NASA estimates that 11 trillion gallons of water would be needed to make up the state's current deficit.