Officials recently released 96 million floating 'shade balls' into the 75-acre Los Angeles Reservoir in Sylmar, California.

The black plastic balls are designed to help protect the water against dust, rain, chemicals and wildlife, as well as prevent 300 million gallons of water from evaporating each year.

The balls work by floating on the surface and blocking the sun's rays.
As well as protecting against evaporation, they also prevent the chemical reaction that creates the carcinogenic compound bromate.

For most people, exposure to bromate - created from naturally-occurring bromide in water -is unlikely to be cause problems.

But some people who ingest large amounts of bromate have suffered nausea, vomiting, diarrhea and abdominal pain.

The balls also form a protective barrier across the surface that helps keep birds, animals and other contaminants out.

Dr Brian White, a now-retired Los Angeles Department of Water and Power (LADWP biologist), was the first person to think of using shade balls for water quality.

The idea came to him when he learned about the application of 'bird balls' in ponds along airfield runways.

His in-house solution has been used in LADWP's open-air reservoirs since 2008 to block sunlight, prevent chemical reactions and curtail algae blooms.

The balls, around the size of a large apple, cost 36 cents each and are black because it is the only colour that is able to deflect UV rays.

(Source & Pics- Daily mail)