Tempe working to restoring lake after dam rupture

TEMPE, AZ - City officials are still confident that Tempe Town Lake can be refilled by November, even as state regulators demand new approval before the man-made structure is restored.

The Arizona Department of Water Resources has told Tempe the department must sign off on a new construction plan. Tempe expects the state will be comfortable with the plans once it shares the information, said Assistant City Manager Jeff Kulaga.

The rubberized dam on the lake's west end ruptured on July 20 and eventually emptied the 977 million gallons of water down the Salt River channel through Phoenix and beyond.

Kulaga said the department issued a permit March 25 to replace the dams. While the lake was to remain full under that plan, a dry lake will allow the city to speed up dam installation.

"What we're replacing them with, that has not changed," Kulaga said. "We don't expect any delays in construction."

Two of four rubber bladder sections already have been delivered to Tempe, one is still being made and fabrication will begin soon on the final segment.

The Department of Water Resources hasn't received the new construction timeline yet but is familiar with the plans, said Michael Johnson, the department's assistant director and chief engineer.

He couldn't guarantee Tempe will have time to fill the lake by Nov. 1. The department is aware of the city's desire to fill the lake soon after plans are approved, Johnson said.

The city is eager to restore the lake in time for the Ironman Triathlon in mid-November, as well as a large number of cool-weather events that are a huge tourism draw.

Tempe began unbolting one of the dams Thursday. The rubber bladders will be investigated to study how much wear and damage they suffered since they were installed to form the lake in 1999.

Each rubber section is about 240 feet long and weighs 40 tons.

The manufacturer, Bridgestone Industrial Products, told the city the dams would last 25-30 years, but Bridgestone and the city determined in 2006 that the lifespan would be much shorter.

In the wake of the dam rupture, there's even more interest in learning how Arizona's heat affected the rubber.

"Analysis of the dams was planned even prior to the rupture," Kulaga said. "Both Bridgestone and the city were interested in that."