A 10 cm black floating ball may hold the key to stopping water supplies from simply evaporating away in drought-stricken areas – and keeping the water free of algae.

The video above shows thousands of the little balls rolling into a reservoir near Calabasas in California. That’s where the Las Virgenes Municipal Water District has covered reservoirs with these “shade balls” in an attempt to stop water from evaporating. The district is experiencing one of the worst droughts the state has ever faced, writes American news outlet NPR.

XavierC, the company behind the creation and manufacture of the balls, writes that the balls take up about 90 % of the surface area of the body of water. They prevent UV rays from reaching the water, thus reducing algae growth. These hollow polyethylene orbs are approximately 10 cm in diameter, and float on water surfaces to stop water evaporation as well as algae growth. They cost just under R4 each.

Although the balls have popularly been dubbed “shade balls” by municipalities and social media users over the last week, they are actually called “Conservation Balls”. But whatever you choose to call them, these balls might be the key to saving our potable water. Just check out #shadeballs on Twitter for pictures.

Source: NPR and Popular Mechanics USA