Original Article: http://news.nationalgeographic.com/2015/08/150812-shade-balls-los-angeles-California-drought-water-environment/

Author: Lisa Ponce

Water Resources Engineering (WRE) connects engineering hydrology and hydraulics with global, economic, environmental, and societal issues. Our student Lisa Ponce makes this connection here…

The news article titled, “Why Did L.A. Drop 96 Million ‘Shade Balls’ Into Its Water?” was published by National Geographic in their August 12, 2015 online news page. The news relates to the WRE domain of hydrology and the specific issue of water evaporating from a reservoir in drought stricken Southern California. The Los Angeles Department of Water and Power had millions of 4-inch black plastic balls put into the Sylmar reservoir. The Sylmar reservoir provides L.A. with billions of gallons of drinking water. The city was hoping to reduce the amount of evaporation, algal and bacterial growth within the reservoir by providing shade over the water. The balls have been tested and have the potential to save the city millions of gallons of drinking water a year. The shade balls are also being used in other parts of California to reduce water usage. According to studies done by the Department of Agricultural Engineering at Oklahoma State University (1965), white floating plastic balls placed in testing ponds were able to reduce evaporation by 78%. The article on ‘shade balls’ stated that they are expecting a reduction in evaporation of 85-90%. This difference may be due to a difference in weather conditions or the difference in color of the balls (black vs. white). Although the ‘shade ball’ idea may reduce evaporation and reduce the amount of water use in L.A., the balls are made out of plastic and could potentially leach contaminants into the water. A study completed by Wagner and Oehlmann (2009) demonstrated that plastic bottled water can contain endocrine disruptors due to the leaching of chemicals from the plastic material. One very important fact that was missing in the National Geographic article was proving that the balls would not leach contaminants into the water. The article only mentioned that a senior policy analyst from the Natural Resources Defense Council stated that the shade balls, “probably won’t release any toxic materials into the water supply.”

The broader contexts areas of economics and society are impacted by the hydrology domain issue of the evaporating water supply in Southern California. The context of society involves the people affected by the issue at hand. This can include people in power such as the government and the people working to create and place the plastic balls, as well as the residents who will be drinking the water. The evaporation of water from the Sylmar reservoir greatly affects the economics of the area because money is being lost due to the loss of water. Society is being affected because the people living in this area are depending on the water sources around them to survive. If the shade balls can greatly reduce the evaporation from the reservoir and other water sources nearby, then Southern California and other parts of the world will have found a way to mitigate the loss of water during extreme drought. If successful, the ‘shade balls’ could save cities millions of dollars by preventing algal and bacterial growth, as well as reducing evaporation. A study published by the National Academy of Sciences displays that as global temperatures have continued to increase, the amount of evaporation in California has also increased (Hayhoe et al., 2004). If an increase in evaporation continues a cause and effect situation would result in civilians being forced to move out of the area which in turn would cause the economy to suffer.



Original Article: http://news.nationalgeographic.com/2015/08/150812-shade-balls-los-angeles-California-drought-water-environment/




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Howard, B., C. (2015). Why Did L.A. Drop 96 Million ‘Shade Balls’ Into Its Water?. National

Geographic. Retrieved from http://news.nationalgeographic.com/2015/08/150812-shade-balls-los-angeles-California-drought-water-environment/

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