It’s part of a $34.5 million project to protect the city’s water supply from the sun.

No, the folks at Las Virgenes’ municipal water district in Los Angeles are not making the world’s biggest ball pit in this mesmerizing video from June.

What’s being dumped from the back of the truck are “shade balls”—hollow, plastic balls measuring 4 inches in diameter that, as the name suggests, block sunlight. They cost 36 cents each, but to the city of L.A., they’re worth much more.

Local news outlets in L.A. reported Monday that 20,000 balls were released into a reservoir at the Van Norman Complex in the Sylmar area of the city. With that move, city officials completed a $34.5 million project that dumped 96 million balls into four reservoirs to protect what’s left of the city’s drinking-water supply.

For a city facing one of the worst droughts in U.S. history, the sun is a tough adversary. Not only does it evaporate millions of gallons of precious water, but it can also cause chemical reactions that make the water unsafe to drink. That’s where the shade balls come in.

The balls float at the surface of the reservoirs to form a cover that prevents sunlight from triggering a reaction between bromide (found naturally in ground water) and chlorine (added to kill bacteria)—which forms carcinogen bromate. They’re expected to last for 10 years and save 300 million gallons of water from evaporating each year. That’s enough drinking water for 8,100 people.

About the Author

Most Popular

  1. Equity

    We'll Need To Reopen Our Cities. But Not Without Making Changes First.

    We must prepare for a protracted battle with coronavirus. But there are changes we can make now to prepare locked-down cities for what’s next.

  2. photo: a For Rent sign in a window in San Francisco.
    Coronavirus

    Do Landlords Deserve a Coronavirus Bailout, Too?

    Some renters and homeowners are getting financial assistance during the economic disruption from the coronavirus pandemic. What about landlords?

  3. photo: Former HUD secretary Julián Castro
    Equity

    How to Head Off a Coronavirus Housing Crisis

    Former HUD secretary and presidential candidate Julián Castro has ideas for state and federal leaders on protecting vulnerable renters from a housing disaster.

  4. Coronavirus

    Black Businesses Left Behind in Covid-19 Relief

    The latest U.S. coronavirus aid package promises a partial and uneven economic recovery that leaves behind the African American community.

  5. photo: 1900 Chinatown fire in Honolulu
    Coronavirus

    The ‘Chinese Flu’ Is Part of a Long History of Racializing Disease

    During a plague outbreak in 1899, officials in Honolulu quarantined and burned the city’s Chinatown. Some Covid-19 talk today echoes their rhetoric.

×