In response to the growing drought concerns in California, Los Angeles has purchased 96 million four-inch balls to cover one of its reservoir. According to the city’s estimations, these black balls could save 300 million gallons of water from evaporating each year.
The city paid 36 cents per ball, and it cost just over three million dollars to complete the project. Before considering the shade balls, the city had looked into using a divider to separate the water and as well as a floating cover. Both of these solutions would have cost the city over 300 million dollars, so the floating balls saved the city hundreds of millions of dollars.
If the city is successful in saving water from evaporation safely, we could soon see these black balls used to cover every source of drinking water in the United States.
How the balls work
Originally designed to prevent birds from landing in drinking water supplies and contaminating the water, it was discovered that the balls also reduced water evaporation by up to 91 percent. The balls provide an effective cover that prevents the water from evaporating as quickly in the sun.
The balls are made of high-density polyethylene (HDPE), which is resistant to both heat and cold. A black UV-stabilizing coating is added to the balls to prevent sunlight from breaking down the plastic and leeching chemicals, oils and other additives into the water. The coating also stops algae from growing in the water and prevents the creation of bromate, a known carcinogen. The balls are BPA-free and certified by the National Science Foundation (NSF) for use in liquids that will be consumed by humans.
When water rises and falls, the balls move too, thus minimizing the loss of water in any conditions. The balls are manufactured by ECC LLC, which is a member of both the American Water Works Association and the Water Environment Federation. Before filling the LA reservoir, the company successfully placed the shade balls in the Ivanhoe, Elysian and Upper Stone Canyon reservoirs in 2008, 2009 and 2012, respectively. According to the company website, the balls cover 90 percent of the water’s surface area and also reduce energy consumption.
Other uses for the balls include the following:
- Wastewater management
- Airport bird control
- Temperature control of water
- Energy savings during mining operations
- Vapor and mist control during mining
- Wildlife protection
- Gas scrubbing
The LA Reservoir can hold up to 3.3 billion gallons of water. Despite the staggering amount of water that the reservoir holds, it can only support the city for three weeks.
— The Alternative Daily