Los Angeles has turned its main reservoir into a giant ball pit.
The city says the balls will shade and cool the water, reducing evaporation from the reservoir and making it less susceptible to algae, bacterial growth, and chemical reactions that can produce harmful substances.
The effort by the Los Angeles Department of Water and Power (LADWP) “is emblematic of the kind of creative thinking we need to meet [the drought’s] challenges,” Garcetti said in a statement.
The balls cost 36 cents each, for a total of $34.5 million. The utility has been testing the concept since 2008, reporting that shade balls reduce evaporation by 85 to 90 percent. That should equate to saving nearly 300 million gallons a year, enough to provide drinking water for 8,100 people, said Los Angeles City Councilmember Mitchell Englander.
The balls also inhibit microorganism growth, reducing the treatment the water must undergo through other means. That could save the city $250 million over time, said Garcetti.
Made of black polyethylene, shade balls are filled with water so they don’t blow away. A coating resists ultraviolet light and degradation. The manufacturers (XavierC, Artisan Screen Process, and Orange Products) say the balls should last about 25 years.
Ed Osann, a senior policy analyst at the Natural Resources Defense Council, told Bloomberg that the shade balls probably won’t release any toxic materials into the water supply.