"Los Angeles Covers Reservoir Waters With 'Shade Balls'"

"LOS ANGELES — Los Angeles has been blackballed.

The city has completed a program of covering open-air reservoirs with floating "shade balls" to protect water quality.

City officials this week dumped the last 20,000 of 96 million black balls into the Los Angeles Reservoir in Sylmar, 25 miles northwest of downtown.

The 4-inch-diameter plastic balls block sunlight from penetrating the 175-acre surface of the reservoir.

That prevents chemical reactions that can cause algae blooms and other problems, allowing the Department of Water and Power to meet U.S. Environmental Protection Agency water-quality requirements."

The Associated Press had the story August 12, 2015.