LA Fighting Drought With Millions of Black Plastic Balls
They prevent evaporation, keep water clean in reservoirs
By Arden Dier,  Newser Staff
Posted Aug 12, 2015 7:46 AM CDT
Updated Aug 16, 2015 2:40 PM CDT

(Newser) – The Los Angeles Reservoir has now turned black, but not from any kind of pollution. Over several months, city officials have been unleashing 96 million black plastic balls into the city's 175-acre reservoir in an effort to fight the effects of California's drought. The final 20,000 were dropped in earlier this week. How is turning the reservoir into what Gizmodo calls a "goth-looking PlayPlace" going to help? Well, the so-called shade balls actually help keep water clear of dust and critters; hinder algae growth; prevent chemical reactions between sunlight and chlorine; and reduce evaporation as they float on the water's surface. At a cost of $34.5 million, or 36 cents each, the city says they're a "cost-effective way to reduce evaporation each year by nearly 300 million gallons, enough to provide drinking water for 8,100 people for a full year."

The 4-inch balls—treated with a chemical to block UV light and designed to last up to 25 years, reports Bloomberg—are also expected to save $250 million compared with another method of complying with clean-water laws, the Los Angeles Times reports. As the EPA recommends water reservoirs be covered, the alternative would be to build a dam dividing the reservoir and install floating covers for $300 million, reports NPR. The Department of Water and Power says it's "the first utility company to use this technology for water quality protection." The shade balls have also been used at three other nearby reservoirs, including one since 2008. "In the midst of California's historic drought, it takes bold ingenuity to maximize my goals for water conservation," LA mayor Eric Garcetti says, per the Huffington Post. This "is emblematic of the kind of creative thinking we need to meet those challenges." (Meet the drought's latest casualty.)