The primary source of this claim is the LA City Council’s Energy and Environment Committee. The official website of LA Mayor's Office writes:
Holding a total of 3.3 billion gallons, enough to supply the entire
city of Los Angeles for up to three weeks, the L.A. Reservoir is
located in LADWP’s Van Norman Complex in Sylmar. At Monday’s event,
Mayor Garcetti was joined byCouncilmember Mitchell Englander, LADWP
General Manager Marcie Edwards and Marty Adams, LADWP Senior Assistant
General Manager of the Water System.
“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
At $0.36 each, the shade balls require no construction, parts, labor
or maintenance aside from occasional rotation. A second, $100 million
ultraviolet treatment facility is due to break ground next -- allowing
LADWP to meet regulatorytimelines, save more than $250 million in
capital improvement costs and further reduce water losses.
“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.”
Said Councilmember Felipe Fuentes, chair of the LA City Council’s
Energy and Environment Committee: “LADWP’s innovative use of shade
balls will protect our water supply and ensure that residents have
access to clean, safe, and ready-to-drink water. As we work to ensure
a more sustainable and resilient future for L.A., I look forward to
more creative, trailblazing and cost-effective solutions.”
Mayor Eric Garcetti announces completion of innovative 'Shade Ball' cover project.
The claim was reblogged by many reputable sources. The Guardian reports:
The idea was conceived in 2007 in an effort to prevent the reservoir
becoming contaminated with bromate, a substance formed when chemicals
in the water react with sunlight. The balls are a relatively low-cost
solution, at $34.5m, and are expected to save about $250m over 10
years, and prevent 300m gallons of water evaporating
96m water-saving shade balls released into LA reservoir
National Geographic News reports:
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
Why Did L.A. Drop 96 Million ‘Shade Balls’ Into Its Water?
The LA mayors site offers the following evidence for the claim:
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. The innovative, in-house solution has been used in
LADWP’s open-air reservoirs since 2008 to block sunlight, prevent
chemical reactions and curtail algae blooms. Currently in place at
Upper Stone, Elysian and Ivanhoe reservoirs, the shade balls come with
the added benefit of reducing evaporation off the reservoir surfaces
by 85 to 90 percent.
In December 2015, Richard Harasick, LADWP’s director of water operations said in a statement:
“we are experiencing cost savings in the reduced use of chlorine
because the shade balls have reduced the amount of algae growth
This means that they are getting positive results since they implemented these into the reservoir system. So, the claim is most likely true.
They're round, so maybe the wind will "roll" them on the water, thus exposing thousandths of an inch of water to evaporation over the ball's surface area?
They are filled with water so that they don't blow away.
They're black, so they absorb heat and maybe transfer it to the water?
Yes, they do. But a special coating reduces this effect.
Made of black polyethylene, shade balls are filled with water so they don’t blow away. A coating resists ultraviolet light and degradation. -- Source
Do these things continue to be effective as the reservoir level rises/lowers?
Yes, if the reservoir level lowers. But if the reservoir level rises, the effectiveness decreases unless more balls are added.
How much water went in to creating 96 million of these things?
That's either classified or unknown. The manufacturers generally don't provide such information unless the customer asks for it.
L.A. Says Goodbye to ‘Shade Balls’
Shade Balls Are a Really Stupid Way to Conserve Water