TEMPE, Ariz. -- Officials have made an official determination about what caused one of the rubber dam bladders at Tempe Town Lake to fail back on July 20.
In a report released Wednesday by Bridgestone and the city of Tempe, experts confirmed what many already knew -- heat and sun exposures caused the bladder to burst. Last month, the 11-year-old dam bladder was sent to an Ohio facility, SEA, Ltd., for testing. According to those test results, the exact cause of the rupture was the separation of the bladder's internal layers.
"The failure was the result of the age of the dam (time) and the environmental conditions (temperature) in which the dam existed."
Crews have spent the past several weeks installing new rubber bladders at the western end of the lake. Three of the bladders are already in place and the installation process is under way. The fourth bladder is due to arrive in October. A cofferdam will be installed in front of that fourth bladder so the city can started fill the lake. That cofferdam will allow water to be pumped out of the construction area so crews can do the necessary work on that final bladder without completely draining the lake; it will be removed once the last bladder is installed.
The new dam will be shaded by a new pedestrian bridge that will span Town Lake from the south bank at Tempe Center for the Arts to the north shore. That bridge will be equipped with a sprinkler system designed to cool the dam.
Under those conditions, experts say the news dam bladders will last at least five years.
The installation of the dam is expected to be complete and the lake refilled by November, just in time for Ford Ironman Arizona, which is one of Tempe's biggest annual events. The pedestrian bridge should be finished in May.