Permanent dam solution for Tempe Town Lake on the table at City Council meeting

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By Catherine Holland By Catherine Holland
By Catherine Holland By Catherine Holland
By Catherine Holland By Catherine Holland

TEMPE, Ariz. – The Tempe City Council is considering a multimillion dollar plan to replace the rubber bladders that comprise the Tempe Town Lake dam with a permanent structure.

The plan is to install a steel-gate dam at the western end of the lake, but with a total price tag of more than $40 million, it’s an expensive solution.

The specific agenda item that will be addressed at Thursday evening’s meeting is a proposed $12.4 million contract with Steel-Fab to design and build the steel-gate dam, which would be made up of eight gates, each more than 100 feet long.

The engineering design is about three-quarters complete. Should the Steel-Fab contract get the green light, that design could then be finalized.

The next contract up for a vote would be a construction deal, which would utilize local subcontractors and create jobs locally. That is on the agenda for next month’s City Council meeting.

If everything goes as scheduled, manufacturing on the steel-gate dam should start in January. On-site construction and installation would begin in April.

The project is slated for completion by Dec. 28, 2015. If it goes past that date, the city will have to start paying a monthly rental fee to Bridgestone for the rubber bladders.

Plans for a permanent dam solution were put in place after one of the four rubber bladders holding back the millions of gallons of lake water burst in spectacular fashion on a summer night in July 2010.

The lake was empty within hours, and it stayed that way for about three months while crews made repairs and installed a replacement bladder.

According to a report released several months after the break, heat and sun exposure were to blame for the bladder's rupture.

"The failure was the result of the age of the dam (time) and the environmental conditions (temperature) in which the dam existed," that report read.

Tempe Town Lake reopened in late October 2010 with a cofferdam in place. The last of the new rubber bladders was installed later. The unique pedestrian bridge over the dam, which also houses sprinklers to cool the rubber bladders and serves as shade for the dam, opened a year later.

On the first anniversary of the dam break, city officials said the new bladders were temporary and would only be in place for five years. The bladder that failed in 2010 was 11 years old.

Tempe Town Lake, with its rubber-bladder dam, was built in the late '90s. It was filled with water from the Central Arizona Project in a process that took more than a month during the summer of 1999. Tempe Town Lake officially opened to the public several months later, on Nov. 7, 1999.

Thursday's City Council meeting, which will be preceded by an executive session and an issue review session, is scheduled to start at 7:30 p.m.