A rubberized dam of the man-made Tempe Town Lake in Arizona burst Tuesday night, July 20 around 10:00 p.m., sending the lake water downstream into the dry Salt River bed.
There were no immediate reports of any injuries and authorities said no structures were in immediate danger.
People near the lake at the time the dam burst said they heard a loud boom and felt the ground shake.
Tempe spokeswoman Kris Baxter estimated that at least three-quarters of the about 1 billion gallons of water had drained overnight. Officials say the dam breach left some areas of the lake with three feet of water or less; the average lake depth is about 16 feet.
“Our biggest concern is to make sure that no one is caught unaware downstream. In particular at this time of year, we have transients who use the riverbed as home,” Tempe Mayor Hugh Hallman said.
It is unclear what caused the dam to burst, but Tempe officials knew the dam needed to be replaced sometime soon. The harsh Arizona sun and dry climate take a toll on the rubberized dams, shortening the life of the dam drastically.
“We already have two bladders in hand and were prepared to do the earthwork but couldn’t,” Tempe City Councilman Corey D. Woods said.
Tempe Fire spokesman Mike Reichling said, “Fortunately, we were prepared for this exact circumstance. Within the last few months we had a drill for what we would do if this happened.”
A press conference providing details of the incident and measures going forward is schedule for 10:00 a.m. PST on Wednesday, July 21.