Los Angeles Drops 400,000 Balls in Reservoir to Fight Suspected Carcinogen

dwp dropping plastic balls

Image from Irfan Khan/LAT

Yes, only in Los Angeles, you might say. If you'll recall, I wrote a story a few months back about the discovery of a suspected carcinogen, bromate, in two large water reservoirs. The Department of Water & Power's (DWP) strategy at the time was: drain now, sweat the hard stuff later.

The new strategy, unveiled yesterday by DWP officials, is to dump hundreds of thousands of plastic balls onto the Ivanhoe Reservoir's surface (a reservoir adjacent to the Silver Lake Reservoir) to shade its water from sunlight. The reason for this rather unorthodox approach is simple: by blocking the sun, you prevent the reaction between bromide and chlorine, which forms bromate, from occurring. The LAT's Francisco Vara-Orta has a nice account of the great ball drop (and a great set of accompanying pictures):

"At a signal from DWP General Manager David Nahai, a dozen crew members began opening dozens of white nylon bags that lined the terra cotta colored edges of the reservoir. Each bag bulged with 2,100 balls.

Resembling a slithering stream of oversized caviar, the black balls rolled thunderously down the reservoir's slopes. "Water quality doesn't get more exciting than this," Marina J.F. Busatto, a DWP biologist said, smiling, to a colleague as she helped slide ball-filled bags to the reservoir's edge.

Within 30 minutes, a portion cordoned off in Ivanhoe was blanketed with the black balls."

So why deploy these balls -- which are typically used by airports to prevent bird congregation on runways -- in particular? Some of the other alternatives, such as a large tarp or metal cover, were considered too costly or impractical. The balls, on the other hand, are (relatively) cheap -- costing 40 cents each -- and are safe for drinking water; black is also the only color able to deflect UV rays.

The DWP has ordered 6.5 million of these balls, 3 million of which it plans on using to blanket the Ivanhoe and Elysian reservoirs. So, yeah, this probably isn't the best solution for the city's water woes but, given the circumstances, maybe the only "realistic" option in the short-term.

Via ::Los Angeles Times: DWP drops 400,000 balls onto Ivanhoe Reservoir (news website)

Water in Los Angeles
::Discovery of Suspected Carcinogen in LA's Water Could Affect National Monitoring Policies
::Care for a Drink... of Toilet Water?
::Water Shortages Hit Long Beach

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