Is it a good idea? Only time will tell. The science behind it is simple. The black plastic balls are known as shade balls. The are dumped into reservoirs to prevent evaporation, just like you might put a bubblewrap cover on your swimming pool, which works really well.
Installing a floating cover would have cost over $300 million, as opposed to $34 million for the balls. The L.A. Reservoir in Sylmar, where the shade balls are deployed holds a total of 3.3 billion gallons, enough to supply the entire city of Los Angeles for up to three weeks.
“In the midst of California’s historic drought, it takes bold ingenuity to maximize my goals for water conservation,” said Mayor Eric Garcetti. “This effort by LADWP is emblematic of the kind of the creative thinking we need to meet those challenges. Together, we’ve led the charge to cut our city’s water usage by 13%, and today we complete an infrastructure investment that saves our ratepayers millions and protects a vital source of drinking water for years to come.”
“As the drought continues, it has never been more important to focus on innovative ways to maintain the highest quality drinking water for our 4 million residents, said Councilmember Mitchell Englander. “In addition to cutting back on the need to chemically treat our water to prevent natural occurrences like algae, these shade balls are 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.”
Dr. Brian White, a now-retired LADWP biologist, was the first person to think of using shade balls for water quality. The idea came to him when he learned about the application of “bird balls” in ponds along airfield runways.