Stabilized HDPE 'Shade Balls' Help Reduce Water Evaporation from L.A. Reservoir
25. August 2015
To help combat California’s devastating draught, a three-year collaboration among custom color and additives masterbatch supplier Techmer PM, Clinton, Tenn., blow molder Artisan Screen Printing, Azusa, Calif., and engineers from the Los Angeles Department of Water and Power (LADWP), culminated to what are reportedly improved "shade balls."
Designed to protect water quality, prevent algae growth, and slow evaporation, the four-inch plastic balls were recently placed in the L.A. Reservoir. This team resulted in solving problems associated with leaking and cracking at the seam lines and the creation of shade balls with a longer life expectancy than previous versions. The new balls are made of HDPE certified for drinking water, and a UV stabilizer and FDA-grade carbon black masterbatch from Techmer PM.
The project is estimated to protect the 3.3 billion gal of water in the reservoir for approximately ten years and annually save 300 million gal of water from evaporating. According to Techmer PM, of the 96 million shade balls used on the project, more than 89 million balls were produced by Artisan Screen Printing and include Techmer PM’s stabilized masterbatches.
Two other manufacturers of the black HDPE shade balls are Orange Products Inc., Allentown, Penn. and Glendora, California-based XavierC LLC. The idea of shade balls is said to have come from retired LADWP biologist Brian White, who was inspired by the “bird balls” used to deter birds in ponds along runways.
The black HDPE hollow shade balls are filled with water and hermetically sealed so they don’t blow away. The U.S. EPA has encouraged the country’s water managers in recent years to find ways to cover or contain their resources to prevent sunlight from reacting with chlorine and possibly creating carcinogens.
While the color of the balls may seem odd, it turns out that carbon black colorants have superior longevity over white TiO2 colorants. Reportedly, for example, there is a significant tensile strength deterioration of white shade balls within eight months versus the 10-year life expectancy of the black shade balls.