A section of the west dam collapsed at Tempe Town Lake Tuesday night, causing about three quarters of the lake to drain. The city is now working on restoring one of its main attractions.
The lake is currently closed and is expected to open Nov. 1 and in time for the Ford Ironman Arizona, said Tempe City Manager Charlie Meyer at a Wednesday press conference.
The effects on Tempe’s economy are not certain yet, said Kris Baxter-Ging, a spokeswoman for Tempe.
“It’s probably going to not be significant,” Baxter-Ging said. “This is our slow period of time for events. It’s so hot out there that while we will be affected, it certainly would not be as much as if this were high season.”
There are some smaller events planned at Tempe Town Lake in the next couple of months, including the Nathan Tempe Triathlon on Sept. 26.
The city is working with coordinators to change triathlons to duathlons, taking out the swim portion of the competition, Baxter-Ging said. Some events may also be pushed to a later date, she added.
About 1 billion gallons of water previously in the lake is now reduced to 3 feet in some areas, compared to the usual average of 16 feet, she said.
Investigation of dam failure
There was no indication of foul play, and for now, it appears the dam broke due to a tear in one of the seams of the rubber dam section, also called a bladder, Meyer said.
There was no prior notice from inspections that the dam was failing, he added.
Don Hawkes, Tempe’s water utilities manager, said the dam was inspected on a monthly basis.
Ceramic chips placed in the dam’s structure may have deteriorated the bladder, though they were originally supposed to prolong the life of the dam, Tempe Mayor Hugh Hallman said.
“In this desert environment…without a watering system, the chips actually added to the deterioration of a piece of the dam structure,” he said.
The exact cause is still under investigation.
Bridgestone Industrial Products, the dam manufacturing company, was supposed to provide the sprinkler system and never did, Baxter-Ging said.
“That was the contingency that we actually have been in disagreement about for a very long time,” she said.
Don Darden, the executive director of communications for Bridgestone Americas, Inc., said in order to find out the cause of the tear, an engineer will need to look at the dam.
However, he said in the severe heat of Arizona that the rubber dams need to be kept cool and wet.
“Our recommendation to them was to make sure that they either had overflow for the dam or to make sure that they had a sprinkling system set up,” Darden said.
The city was to provide its own system until a new agreement was reached in 2009, he said in an e-mail, and Bridgestone installed a spray system that was supposed to be managed by the city after that.
He said the city “chose not to reinstall the spray system this year.”
Lucky timing
Because the dam was already expected to be repaired soon, that section of the lake was closed, Hallman said.
Anyone on the lake at that time would not have been in danger and would only have noticed the water level lowering, since the water was only flowing at a rate of 15,000 cubic feet per second, Hallman said.
If crews had started repairing the bladder while it collapsed, people could have died, Hallman said.
“Sometimes it’s better to be lucky than good,” Hallman said. “Thank God that the event occurred last night instead of today.”
There have been no reported injuries or deaths, he said. Public safety officials and police responded quickly Tuesday night after a 911 call.
Process of recovery
The replacement process was already scheduled for Wednesday before the dam broke, so that process was continued and the bladders at the west dam were deflated.
The four bladders will be replaced at the west dam, Baxter-Ging said.
The bladders were not replaced earlier because of weather conditions, like storm flows, that affect the amount of water in the lake.
It would’ve possibly cost more money to repair the dam if the lake had been filled, city officials said. Bridgestone has agreed to pay the city $3 million, money that will hopefully cover the cost of refilling the lake among other expenses.
“This has been a relationship that has been troubling for some time,” Hallman said of Tempe and Bridgestone, though he hopes the company will help with public safety during the dam’s restoration process.
The warranty was guaranteed for 10 years, and the structures lasted 11. Hallman said Bridgestone promised the dam systems would last about 30 years.
After the damage is fixed, Tempe will not pursue another contract with the company, Hallman said.
New technology from other manufacturers will be added within five years, he said, including a water system, automatic alert system and a bridge built across the dam structures for shade.
Darden said the company announced in 2008 that it was not going to continue in the rubber dam business anyway, so the company was just finishing up the agreement with the city and helping to find a long-term solution.
ASU student witnesses
Maureen Howell, who is registered as an ASU public policy graduate student for the fall, said she called 911 at 9:45 p.m. after her friend saw the dam break.
“We were riding our bikes, and we were right where the dam is actually,” Howell said. “There was a huge explosion sound and the dam just burst, and there was big waves of water, I’d say as tall as the dam, coming over.
“I called 911, and I was kind of nervous that they were going to think I was joking, but they believed me and the cops were here by the time I was off the phone with the operator,” Howell said.
It took about 10 to 15 minutes for the alarm sirens to go off after the dam burst, she said.
Preston Swan, registered as a public administration master’s student at ASU in the fall, said he happened to be looking over at the dam because a light was flickering.
“I saw the inflatable wall burst and water just gushed over it and wiped everything out,” Swan said.
He said he was shocked and also a little excited, and that the bursting sounded like a loud bang or popping noise.
“It was a kind of a once-in-a-lifetime thing,” Swan said. “I knew I couldn’t stop it, so I figured I’d just stay there and watch it.”
As a Tempe native, he said he remembers when the lake used to be just a “dry ditch.” And he would go to the lake to hang out with friends.
“I’ve seen the economy rise around it, and it was kind of a rallying point for Tempe, so it’s a shame that it had to have this kind of setback,” Swan said.
Reach the reporter at reweaver@asu.edu
