If you ever come across a body of water with mysterious black balls, there actually shade balls, or small plastic spheres floated on top of a reservoir for environmental protection and to slow evaporation. Initially, they were developed to prevent birds from landing on toxic tailing ponds produced by mining operations. In 2014 – 2015, the Los Angeles Department of Water and Power deployed 96 million shade balls on its largest reservoir in response to the United States Environmental Protection Agency’s surface water treatment rule, a nd claims that in addition to reducing evaporation, they also reduce UV radiation by-products and algae growth. Read more for an up-close look video and additional information.
The balls saved approximately 1.7 million cubic metres of water from evaporating during their deployment from August 2015 to March 2017. However they required 2.9 million cubic meters of water in their manufacture. Nonetheless, the balls have a lifespan of ten years, and the plastic may be reused after that.