Covering California's reservoirs was a hit.
How it mitigated the 2015 drought
The state of California experienced one of the worst droughts in its history during the year 2015. The solution that scientists came up with to protect the reservoirs that supply Los Angeles with water was to cover them with millions of black plastic balls. The idea was a success.
Authorities covered the four main reservoirs in the city of Los Angeles with these polyethylene balls, which are just 10 centimeters in diameter, to create a protective layer against the sun's rays. One of the goals was to prevent water from evaporating during the state's drought.
Another goal of the project was to prevent water pollution. These reservoirs use a type of chlorine to purify the water which, when it comes into contact with sunlight and ultraviolet radiation, can generate a chemical compound called bromate, which is harmful to health. The plastic balls, being black, would completely block the ultraviolet rays and thus prevent the chemical reaction from happening.
The experiment of the so-called Shade Balls turned out to be a success, as announced by the Los Angeles City Department of Energy and Water. Each year, the polyethylene balls helped prevent up to 1.3 million cubic meters of water from disappearing, as well as preventing the formation of algae on the surface.
Original source: Gizmodo