The committee in charge of choosing a new design for the Tempe Town Lake’s west dam held an open house Monday at the Tempe Center for the Arts to discuss their progress.
The entire lake drained in July 2010 when one section of the west dam burst because of old age and heat exposure. Temporary inflatable bladders replaced each of the dam’s four sections.
A total of four possible dam designs have been selected, with two seen as more feasible. A final decision will be made in November.
The two designs the committee most favors are inflatable rubber dams — similar to the rubber sections currently in place — and an Obermeyer dam — a structure consisting of steel gates supported by inflatable air bladders underneath.
“Obermeyer is a good system, and rubber bladder is good as well; it’s used all over the world,” said city manager Jeff Kulaga, one of the committee members.
The project is estimated to cost about $49 million, with about $367,000 already given to Gannett Fleming, Inc. for analysis of the dam. This includes design, materials and construction, but does not include any work done to the east dam, which the city does not have any current plans to replace.
Kulaga said the dam that is chosen must meet certain requirements.
“Obviously, the dam must maintain the waters of Tempe Town Lake,” Kulaga said. “It also has to have the flexibility to move up and down to provide moderate flows and be able to go back to an upright position.”
About 20 possible dam designs were originally considered, but the committee rejected the more improbable ones and is now considering four possibilities.
“Essentially, what we want to do is to look at the overall reliability of each dam in certain conditions and come up with any way we think it can fail and compare that with each system,” said Dean Durkee, vice president of Gannett Fleming, the firm in charge of building the new dam.
The committee now has to refine the search and present a final dam plan to the city by next month.
“It comes down to the city staff recommending it to the City Mayoral Council and them accepting it and making the final approvals,” Kulaga said. “We have experts in hydraulics to make cost benefits and make sure (the new dam) is a safe solution.”
Reach the reporter at sdinell@asu.edu
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