Silver Lake Reservoir's contaminated water was drained this year. The reservoir doesn't need covering because the recently replenished supply is not chlorinated until after it leaves its basin.
But the discovery of bromate prompted officials to look for ways of shading Elysian and Ivanhoe. A tarp would have been too expensive and a metal cover would take too long to install, especially in a year of drought.
So one of the DWP's biologists, Brian White, suggested "bird balls," commonly used by airports to prevent birds from congregating in wet areas alongside runways.
DWP officials and Orange Products, the Allentown, Pa., company that produces the balls, said this was the first time a major utility had used the globes to solve a water- quality problem for a drinking supply. White said Orange Products is the only company in the United States that could manufacture the balls, which are environmentally safe for drinking water and approved by NSF International, a government-sanctioned, nonprofit water quality organization.
The balls, which cost 40 cents each, are made of polyethylene. The coating contains carbon. Black is the only color strong enough to deflect ultraviolet rays, said Paul Sachdev, president of Orange Products.
The company is producing about 100,000 balls a day -- its largest order this summer -- to meet DWP's order of 6.5 million. Each bag will be dumped as it arrives, with Ivanhoe getting the first batches until fully covered.
The DWP's Parekh noted that the "balls require no construction, no parts, no labor, no maintenance."
Ivanhoe and Elysian reservoirs will be blanketed by about 3 million balls each for about four years, Parekh said. They will be removed when a covered replacement reservoir is built near Griffith Park's Travel Town area.
LaBonge acknowledged that the black layer wasn't as pretty as the old face of Ivanhoe, but said its beauty would come back when the area's reservoirs are retired and probably made into recreational areas that the public is working with officials to design.
"We know the beauty and purpose underneath," he said.
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francisco.varaorta@latimes.com
