May 07, 2008
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The Los Angeles Department of Water and Power started filling Silver Lake Reservoir Wednesday, months after it was drained because of a potentially harmful chemical in the water. KPCC's Shirley Jahad spoke with DWP General Manager David Nahai.
Shirley Jahad: Department of Water and Power officials today turned on the tap to refill Silver Lake Reservoir. Officials had dumped hundreds of millions of gallons of water and emptied Silver Lake and Elysian reservoirs after finding levels of a potentially harmful chemical, bromate, in the water. Joining me now is DWP chief David Nahai. Good afternoon, sir.
David Nahai: Good afternoon, Shirley.
Jahad: First off, tell us what's happening there at Silver Lake now, today.
Nahai: Well, as you said, the reservoir had been drained, and we'd promised to fill it up again so that it would be full in order to meet water supply needs during the summer months, and really, in order to return a landmark to the Silver Lake community. And today, we did that by, as you said, turning on the spigot and allowing water to flow back into the reservoir.
Jahad: It's going to take a couple of weeks or more to fill it up. Where's all this new water coming from?
Nahai: From the Eastern Sierras. This is snow melt. It is the most pristine, the most delicious water that we have, I think probably the best water anywhere, and it will take about 20 days to fill the reservoir. The reservoir, in terms of its size, is something like 96 football fields.
Jahad: There is a near record low snow pact now, according to recent measurements, so what's the effect of taking that to fill Silver Lake?
Nahai: Well, it's going to the city's water supply. Instead of using it in other places in the city, we're using it in order to refill the Silver Lake Reservoir, I hope much to the delight of the communities of the central and south L.A. who have the benefit of it.
Jahad: Now, I understand the bromate got there in the first place, it wasn't by any accident or any dumping, it was a natural process of exposure to sunlight and a chemical reaction in the water. How can you ensure whatever chemical happened before won't happen again?
Nahai: It's, yes, a natural reaction, but a very, very unusual one. As a matter of fact, it appears quite unprecedented. Nobody was able to discover an instance of this happening anywhere else. And what happened here was that this was a combination of chlorine in the water, bromide, which is benign, acting together with sunlight in order to create the chemical bromate. And the way that we're going to prevent that from happening is by shielding the water from sunlight in the future during the time that Silver Lake will remain in service as a water supply resource.
Jahad: How are you shielding Silver Lake from sunlight?
Nahai: It's going to be done by what are called "birds balls." (laughs) And I know that that sounds terrible. But bird balls will be used actually on Ivanhoe. During the period of time that Silver Lake will remain as a water supply resource, it will not be covered, but in terms of long term use, if it were going to remain part of the city's water supply, it would have to be covered as Ivanhoe is going to be, with there– with these black balls that float on top of the water and shield it from sunlight to a sufficient degree to prevent the formation of bromate.
Jahad: Where did the nearly billion gallons of the contaminated water go?
Nahai: To the extent that we could, we used it for reuse purposes, but most of it, I'm afraid, was discharged into the L.A. River and out to the ocean. I do want to say that we could have possibly blended the water with other water and rendered it possibly usable for drinking purposes, but we made the decision, I made the decision, in the interest of public perception and public safety, that it was preferable, as hard as it was, to not use that water for drinking purposes.
Jahad: I understand some 600,000 people in parts of central and south Los Angeles use the Silver Lake Reservoir for their tap water. What is your message to them in terms of safety and the water?
Nahai: Well, I think my message to them is going to be, rather than have any mother in central and south L.A. have any doubt about the water that her kids are drinking, we decided just to dump that water. The other message that I would like to give to the people of Los Angeles as a whole is that it is tested, constantly. Our water is tested something like 350,000 times a year. That's about a thousand times a day, to make sure that Angelenos enjoy the safest, most high quality water anywhere.
Jahad: Thank you very much, David Nahai
Nahai: Thank you for having me.
Jahad: We've been talking with David Nahai, the head of the L.A. Department of Water and Power. I'm Shirley Jahad.
