Can 96 million balls improve water quality? 
 
 Los Angeles is about to find out. On Monday, Mayor Eric Garcetti was at the Los Angeles Reservoir to mark the addition of 20,000 of the small balls to the lake. 
 
 But what exactly are those balls and how will they help? 
 
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 What are those black things in the Los Angeles Reservoir? 
 
 They’re 96 million shade balls. Shade balls are used to protect water quality, prevent algae growth and slow evaporation from the city’s reservoirs. The L.A. Reservoir is the Department of Water and Power’s largest in-basin facility. Its surface is 175 acres, and it holds more than 3.3 billion gallons of water. The shade balls are expected to save 300 million gallons a year from evaporating from this particular reservoir. 
 
 Why is this project in the news now? 
 
 Garcetti helped DWP officials release the final 20,000 shade balls into the reservoir Monday. “In the midst of California’s historic drought, it takes bold ingenuity to maximize my goals for water conservation. This effort by LADWP is emblematic of the kind of the creative thinking we need to meet those challenges,” Garcetti said. 
 
 So, how much did this project cost? Weren’t there alternatives to placing millions of plastic balls in the water? 
 
 The project cost $34.5 million, which comes to about 36 cents per shade ball. Artisan Screen Printing, a company based in Azusa, supplied 89.6 million of the balls. The remaining 6.4 million came from XavierC LLC in Glendora. 
 
 Because of the size of the reservoir, DWP could not install one protective cover. Instead, utility officials would have had to divide the reservoir in two and install two separate covers at a cost of $300 million. 
 
 Is it safe to put that plastic in our water? 
 
 DWP says this is perfectly safe. The 4-inch-diameter balls are made from high-density polyethylene, which is the same material you would find in a one-gallon milk jug. This plastic is approved to come into contact with drinking water. 
 
 The balls do not emit any chemicals, according to the DWP. They should last 10 years. At some point, they will lose their structural integrity and could split at the seams. 
 
 Why are the balls black? 
 
 Carbon black was added to the plastic to stabilize the balls in UV light from the sun. 
 
 Is this the first time DWP has used shade balls in a reservoir? 
 
 No. In fact, it’s been a fairly common practice for the utility since 2008. The Upper Stone, Elysian and Ivanhoe reservoirs all have shade balls to protect their water quality and prevent evaporation. 
 
 Who came up with the idea for shade balls? 
 
 Shade balls are the brainchild of Brian White, who was a biologist with the utility. He based the idea on “bird balls” that he observed in waterways near airport runways. 
 
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 UPDATES 
 
 12:19 p.m.: The article has been updated throughout with additional details and background. 
 
 Aug 12, 11:22 a.m. This article has been updated with additional details. 
 
 This article was originally published Aug. 11 at 1:36 p.m. 

 For months, the Los Angeles Department of Water and Power has been releasing the black plastic balls to float on the surface of the 175-acre Los Angeles Reservoir in a massive drought relief project. The final 20,000 went in on Monday, with some assistance from LA Mayor Eric Garcetti. 
 
 Los Angeles can't make it rain, but it can shield its precious water with "shade balls" -- 96 million of them to be exact. 
 
 By deflecting UV rays, the opaque spheres are expected to protect more than 300 million gallons of water from evaporating in Southern California's harsh sunlight every year. 
 
 LADWP was the first utility company to use this technology to protect water, according to a press release from Garcetti. 
 
 "In the midst of California's historic drought, it takes bold ingenuity to maximize my goals for water conservation," the mayor said. "This effort by LADWP is emblematic of the kind of creative thinking we need to meet those challenges." 
 
 Besides slowing evaporation, the shade balls prevent sunlight from triggering a dangerous reaction between bromite, a chemical occurring naturally in groundwater, and the chlorine used to disinfect the water. When sunlight interacts with those two chemicals, Plastic News explains, the suspected carcinogen bromate is formed. 
 
 The shade balls also deter wildlife from contaminating the reservoir, shield the water from wind-blow dust and discourage algae from forming on the water's surface. 
 
 City officials hailed the shade balls as very cost-effective. They run just 36 cents a piece, The Guardian noted, and require no additional construction or maintenance -- except to be rotated occasionally. 
 
 "Shade balls are a great example of how engineering meets common sense," LADWP general manager Marcie Edwards said in Garcetti's press release. "... As we make updates, we are mindful to be wise and practical with our investments. Shade balls are an affordable and effective way to comply with regulations, and help us continue to deliver the best drinking water to our customers." 
 
 Watching the shade balls cascade into LA's largest reservoir is also completely mesmerizing. Take a look at the photos below: 

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 Shade balls? 
 
 They emerged from obscurity Tuesday morning on the Internet with all the markings of Buzzphrase of the Year. It’s shady. It’s enigmatic. To stoke juvenile social media glee, it has the word “balls” in it. And it’s dead serious. 
 
 The final 20,000 of 96 million shade balls are released at the LA Reservoir, on Aug. 10, 2015. Photographer: Gene Blevins/ZUMA via Corbis 
 
 Here’s what “shade ball” meant before this morning, according to the slang authority urbandictionary.com: 
 
 And now: 
 
 Ok everyone has the next 90 min to get in their best #shadeballs jokes. Then it becomes passÃƒÂ©. Deal? — The Hoffington Post (@_hoffman) August 11, 2015 
 
 I cannot get enough of local LA newscasters saying #ShadeBalls — Wu Sean Pat (@thenewconfucius) August 10, 2015 
 
 The shade balls of Los Angeles are 4 inches in diameter, hollow, polyethylene orbs made by XavierC, of Glendora, Calif.; Artisan Screen Process, of Azuza, Calif.; and Orange Products, of Allentown, Penn. The Los Angeles Department of Water and Power has now dumped 96 million balls into local reservoirs to reduce evaporation and block sunlight from encouraging algae growth and toxic chemical reactions. The balls are coated with a chemical that blocks ultraviolet light and helps the spheres last as long as 25 years. Las Virgenes, north of L.A., now uses shade balls, too. 
 
 These are not your average Chuck E. Cheese’s ball-pit numbers. They’re hermetically sealed, with water inside them as ballast, lest when the wind picks up “they’ll blow out, and you’ll be chasing them down the road,” says Sydney Chase, president of XavierC. You could drink the ballast—don’t want nonpotable water leaking into the reservoirs. 
 
 Chase is a 30-year veteran of manufacturing who left a $300,000 job to start XavierC. She sold her house to raise the capital to seed the company. “Either I’m going to end up under an overpass, or this is going to take off,” she recalls thinking. And as much fun as there is to have with “shade balls,” the company was founded for two serious reasons. 
 
 The final 20,000 black shade balls are released during a news conference at the LA Reservoir on Aug. 10 in Sylmar, California. Photographer: Gene Blevins/LA Daily News via Zumapress.com 
 
 Chase calls her product “conservation balls,” because they can help keep reservoirs intact and clean. They’re also seeing use on the tailing ponds where miners store contaminated water, to keep birds away from toxic agents, and in wastewater treatment facilities, to keep odors at bay. They cost about 36¢ each to make. Chase declined to talk about XavierC’s financial performance. 
 
 The second reason is built into the company’s name. The “Xavier” is Xavier Castillo, who worked for 18 years in information technology at the Pomona-based Casa Colina physical rehabilitation center. Castillo, 47, survived a car accident at 27 that left him a quadriplegic. He and Chase met by chance four years ago, and he came on board when he learned she wanted to hire disabled veterans who’d been having trouble finding work elsewhere. Factory work itself would be difficult for many of them, so Chase envisioned a company at which vets could perform administrative, marketing, and other tasks on a computer. Castillo controls his own computer using his neck and shoulder muscles, Chase says. 
 
 Her involvement can get a lot more personal. At a business meeting earlier this year, Castillo started having a seizure and stopped breathing, and Chase resuscitated him: “I was shaking so hard, I could barely talk,” she says. 
 
 The second of 10 children in a family where some have served in the military, Chase says she was moved by the images of America’s war-injured. “Honestly, it’s just seeing these kids coming home,” she says. “They’re very physical people, and you come back not able to do things you were made to do. It just kind of broke my heart.’ 
 
 The U.S. Environmental Protection Agency has encouraged the nation’s water managers in recent years to find ways to cover or contain their resources, to prevent sunlight from reacting with chlorine and possibly creating carcinogens, says Ed Osann, a senior policy analyst at the Natural Resources Defense Council. The shade balls shouldn’t pose a pollution problem in themselves, he says, since “everything that comes in contact with drinking water has to be a certified material.” Chase says the balls are designed not to degrade. 
 
 The shade balls are a novel way to protect drinking water, and Californians’ latest attempt to adjust to their four-year drought. But they reflect a larger question: What can we do to the earth, its water, air, and land, to mitigate climate-related changes? 
 
 Today it’s shade balls. In the future we might have to send millions of reflective 1-inch metal-walled balloons up to the Arctic to act as synthetic sea ice to bounce sunlight away and slow the melting. (A fanciful but actual suggestion made by the inventor of the hydrogen bomb.) 
 
 L.A.’s shade balls experiment is geo-engineering writ small. Something to consider, as elsewhere scientists struggle to understand geo-engineering writ large. 
 
 Watch this next: 

 If you’re an Angeleno, you’re probably used to the black plastic balls floating in local reservoirs. But the rest of us may be wondering why LA’s turning a massive water source into a goth-looking PlayPlace. The answer? To keep the drought-stricken area’s water clean and protect it from evaporation. 
 
 
 
 On Monday, LA mayor Eric Garcetti dumped 20,000 so-called “shade balls” into the Los Angeles Reservoir. It’s the final stage of that city’s water quality protection plan, an effort costing $34.5 million. A shade ball, which sounds like it could be a Pokemon move, is actually a clever water-cleaning device: Each one reduces evaporation, protects against animals and dirt, and costs a mere 36 cents. A total of 96 million have been poured into the 175-acre reservoir, which holds up to 3.3 billion gallons of water. 
 
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 LA is the first city to use this type of innovation for water quality control. Shade balls are also useful for staving off algae growth and preventing harmful chemical reactions between sunlight and chlorine. In a press release, the city claims 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.” 
 
 The onyx-colored buoyant ball pit joins other inventive anti-drought measures that have popped up in recent years: One startup is helping farmers install sensors that read soil levels and tell farmers when to judiciously irrigate, for example. Meanwhile, this handheld fog catcher scoops moisture out of the air and voila: Water for your coffee. 
 
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 Up next, the Los Angeles Department of Water and Power is getting ready to open a $100 million ultraviolet water treatment facility that it says will keep LA water safe and help cut losses. In the meantime, we’ll see if the army of li’l plastic balls keeps the drought at bay. 
 
 [Los Angeles Department of Water and Power and LAMayor.org via Bloomberg] 
 
 Top image: Los Angeles mayor Eric Garcetti helping deploy shade balls yesterday at the LA Reservoir, via LAMayor.org
– 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.)