Horizon, Host: Ted Simons

August 12, 2010

Host: Ted Simons

Tempe Town Lake Dam Break

  • Tempe Mayor Hugh Hallman has the latest on efforts to replace the dam that ruptured July 20th.
  • Hugh Hallman - Mayor of Tempe
Category: Government

View Transcript
Ted Simons:
It's within just over three weeks since the dam at Tempe town lake ruptured, spilling close to a billion gallons of water into the mostly dry Salt River bed. In a moment, we'll hear from Tempe mayor Hugh hallman about the latest on efforts to replace the dam, but first, David Majure and photographer Scot Olson provide a look back at what happened.

David Majure:
It changed overnight. From full to foul.

>> Now that the lake is empty, there's going to be a smell.

David Majure:
Eye catching to eyesore. Recreational to just plain wrecked. Tempe town lake was a very different place before the night of July 20th when a section of the inflatable rubber dam burst.

9-1-1. What is your emergency?

>> I'm at Tempe town lake and I believe a section of the dam on the lake might have just given way.

Hugh Hallman:
Last night, we had a failure of the number two bladder. It's the piece you see behind us. It's something we've been concerned about for some time has occurred.

David Majure:
Tempe officials say they knew the dam was ill equipped to withstand the harsh desert heat. They were designed to have a watering system to have water over the dam. It was supposed to keep the rubber cool and make it last longer, but Tempe mayor says it doesn't last.

Hugh Hallman:
In this desert environment with the cold of the winter and heat of the summer and without the watering system, the chips actually added to the deterioration of the piece of the dam structure.

David Majure:
Officials say monthly inspections reveal no immediate risk of failure, but there were signs that the 10-year old dam might not last.

Hugh Hallman:
These dam systems were reported to last at least 30 years.

David Majure:
In April 2009, the maker of the dam, Bridgestone industrial products, agreed to replace the rubber segments and cover the costs up to $3 million. In fact, work was supposed to start the day after it ruptured.

Hugh Hallman:
Fortunately, if it was going to occur, it occurred yesterday avoiding any loss of life to the crews associated with the repairs.

David Majure:
It should be easier, faster and less expensive. The replacement dam is temporary. After five years, the city has to buy and install a new dam.

Hugh Hallman:
We will switch to another technology, either a rubber dam manufacturer with a clear record or other technology.

Ted Simons:
Joining me now to discuss efforts to replace the dam is Tempe mayor Hugh Hallman. Thanks for joining us. Good to see you. Update us on what's happening right now at the lake.

Hugh Hallman:
We're in the process of replacing the rubber dam segments -- the bladders is what they're called -- as we speak. When the event occurred, we had two of the segments in-house, the third had been completed in the manufacturing process and was in the process of being shipped and the fourth was starting manufacturing. We have pushed Bridgestone hard to replace the segments but it takes time. This is a very sophisticated well-engineered product and planning the replacement with flood flows that come in the spring took longer.

Ted Simons:
These are five years at best?

Hugh Hallman:
The segments we'll use for five years. That was part of the condition with Bridgestone. They're leaving the rubber dam manufacturing business and didn't want to have a continuing dam sitting out there. The agreement was they provide these dam segments at no charge and install them at bridgestone cost. They'll be saving money and that's because of the segment lost air, probably with $800,000, it will be saved. The original method by which they would have been replaced, install a steel structure on the back side of the dam. Water is pumped out and areas that empty, the dam rubber segment gets taken out and a new one put in. This time, with the river gone, essentially -- the water is now in Phoenix -- the dam segments can be replaced quickly. We'll use a cofferdam for the fourth segment. We want to refill the lake but not rely on the -- Will these last for five years? Significantly longer, but we agreed with Bridgestone to replace the dam segments within five years.

Ted Simons:
What options do you have as far as a permanent dam?

Hugh Hallman:
There are obviously hundreds if not thousands of dams across the country we can look to to get good experience and knowledge about what may be the best technology. We also have valuable experience and understanding. This manufacturer, leaving the industry, there's a manufacturer, Sumitomo, who have a clear record and that's still a technology we're examining. The dam segments would be replaced every 15 years if we go to that kind of technology. There are steel gates that are operated -- pneumatically in this case -- and gates that rise from the top. We would have to replace the dam structures that exist under each of them. Our goal is to make sure we're making the selection based on longevity. A sustainable system and I don't think those questions were asked when the original dam was put in place in 1996 at a cost of $16.8 million. Nobody was asking the question, I think, directly, what is the long-term lifetime of those things and how do we replace them? We do own a cofferdam. In this case, we're looking for a 60-year lifetime solution. We might use rubber dam segments that get replaced more frequently. Might use a steel structure. The goal is to select a technology where the operation and maintenance costs and replacement costs get us to a sustainable number. $500,000 to $750,000 a year. The lake costs about $3.1 million a year to run. The value to our community in terms of new residential and recreational amenities is significant. We have to weigh in the balance that value and what the community should pay for it. The lake has to pay for itself and that's one of reasons I ran for mayor. We have to operate this entire project in a way it does not become a burden to our taxpayers or community.

Ted Simons:
Talk about the burden to Tempe. What is this going to cost Tempe to not only replace the dams -- I know Bridgestone is responsible for some if not all of this -- and getting the new technology in place? Does Tempe have the money for this?

Hugh Hallman:
Let's start with the first question and sometimes reporters don't want to believe the answer. Bridgestone, under a contract we negotiated, agreed to pay for the replacement. That came about because one of the reasons I ran for office in '98 and mayor in 2004, my concern how the lake should operate. In this instance, one of the issues I was concerned about when I ran the first time in '98, we were promised 30-year dams but only got a 10-year warranty. Concerns were raised and we addressed those and we reached a new agreement. They would replace the dam structures. Didn't happen as fast as I would like, but I suspect that Bridgestone wished it happened more quickly too. The long-term solution, again, we're looking for something and we have technologies identified that likely get us in the range of $500,000 to $750,000 in a replacement life cycle costing. That's within the realm of the lake operations. This is not as dire an issue as some would like to make it. A 60-year life recycle has real dollars associated with it. Ask what it costs to run a golf course for 60 years, a library. That's a responsible approach here.

Ted Simons:
The last question. Only a minute or so left. There are some who say that now that the opportunity is there, there shouldn't be a lake. The lake shouldn't be there. How do you feel about that? There's some folks who have a problem with that lake.

Hugh Hallman:
A lot of folks who have a problem with the lake identify things like water conservation and water use. But these are the numbers they have to run into and deal with directly. The lake has about three million people a year who use it. An average golf course has about 80,000 people who use it. The amount of water for town lake is the equivalent of what it takes to water about two golf courses. We could have 160,000 people using the amount of water on a golf course, or two, or three million people currently who use the water for that benefit. And a lot of that water lost goes into the aquifer.

Ted Simons:
Good luck getting that thing fixed.

Hugh Hallman:
Thank you very much.

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