(SOUNDBITE OF ARCHIVED RECORDING)
UNIDENTIFIED MAN: Shade balls away.
ROBERT SIEGEL, HOST:
Thousands of plastic balls splashing into the Los Angeles reservoir - they are a small share of nearly 100 million of them floating, covering the reservoir's surface. The release of these shade balls was, in a sense, federally mandated. Richard Harasick is director of water operation at the Los Angeles Department of Water and Power. He joins me now to explain. Welcome to the program.
RICHARD HARASICK: Glad to be here.
SIEGEL: Ninety-six million shiny black balls now covering the surface of the Los Angeles reservoir - explain the reason for it.
HARASICK: This is one of our largest - this is our largest reservoir in our system. And these small plastic shade balls protect the water quality by preventing sunlight-triggered chemical reactions that occur, and they deter birds and other wildlife and protect the water from producing disinfection byproducts.
SIEGEL: Also from evaporating, to some degree.
HARASICK: They do reduce evaporation. And in our case, for this reservoir of this size, up to 300 million gallons of water every year, which is enough to fill five Rose Bowls.
SIEGEL: (Laughter). That thought boggles the mind. And this is compliance with an Environmental Protection Agency regulation that a reservoir like this one should be covered in some way.
HARASICK: Yes. There are a number of regulations from the EPA, notably the surface water treatment rule, which basically says when you have a body of water which is open to atmosphere and subject to runoff, that you have to cover it or otherwise take it off-line or filter it.
SIEGEL: And the choice of the plastic shade balls as opposed to some other kind of covering - if you were to compare cost, what's the difference?
HARASICK: Well, the initial thought to solve this problem would be to put a fixed roof on this or even what's called a floating cover. But the reservoir is so huge that either one of those alternatives would have been not only incredibly expensive - you know, $250 million, which was the savings by going to shade balls - but, you know, something like that had never been done before. So through the innovative use of these shade balls, we've saved our customers $250 million in capital cost and solved the problem in a - really, a more elegant way.
SIEGEL: Is this novel, or where did you figure out this idea to use plastic balls to cover the entire surface of the reservoir?
HARASICK: We first saw these used at airports where they have detention basins for storm runoff that comes off of the runways. They fill up, and they attract birds. So the airports put these - what they call bird balls - on those ponds to keep the birds off. And so we saw this as a way to keep sunlight off of our reservoirs. And that's the solution we were looking for. The regulations that we were trying to meet are trying to reduce carcinogens that are developed when you mix chlorine and algae. And so we decided to put shade balls on it.
SIEGEL: I'm just curious. With a little bit of water inside, if you throw this, does it sort of flow like a knuckleball, or does it go pretty straight? What would you - how would you describe it?
HARASICK: (Laughter). Yeah, it would throw probably just like a softball. It doesn't kind of wobble like a wounded duck at all. And you're right to ask that question because any red-blooded American would pick up one of those, including the mayor the other day. When we had our ceremonial last release, he threw the one that he had, just straight-sailed right into the reservoir.
SIEGEL: Nobody brought a Wiffle bat to the ceremony to fungo a couple out there into the reservoir?
HARASICK: (Laughter). Well, you know, our communications people thought to get some members of the LA Dodgers out there to help us out, but we passed on that one.
SIEGEL: Well, Mr. Harasick, thanks a lot for talking with us about the shade balls in the Los Angeles reservoir.
HARASICK: Well, thank you for your interest. These are important issues to us, and we're glad that you're discussing it with us.
SIEGEL: Richard Harasick, director of water operation at the Los Angeles Department of Water and Power. Transcript provided by NPR, Copyright NPR.