As Hurricane Irma approaches, U.S. Army Corps of Engineers Jacksonville District officials say the Herbert Hoover Dike that surrounds Lake Okeechobee is at “low risk” of damage from the storm.
Jacksonville District Commander Col. Jason Kirk said the track for the predicted landfall of Hurricane Irma continues to change. If it does impact the lake, the corps believes the dike will hold.
“We could have some wind-induced overwash at the construction site near Clewiston,” he said, referring to a project to replace a culvert in the Herbert Hoover Dike.
He said the corps continually monitors the dike and will continue to monitor weather forecasts and work with national, state and local governments and agencies.
“We believe the impacts to the Herbert Hoover Dike are unlikely,” said Laureen Borochaner, Jacksonville District Engineering Division Chief and Dam Safety Officer. The lower than average lake level means there is less stress on the dike, she said.
She said that from the information they have received from the National Weather Service, they predict that if the hurricane hits the big lake area, it will be a Category 4 storm.
She said they are conducting an orderly shutdown of construction operations and have pre-positioned staff to inspect the dike after the hurricane.
She said Hurricane Irma is expected to dump about 8 to 10 inches of rain on the area. If the storm moves into the Kissimmee River basin, that rainfall would multiply as the water drains south. The storm brings the potential for the lake to rise 8 to 10 inches as the storm passes, and another 2 feet over the next few weeks for a total increase of about 3 feet.
Efforts to lower the lake level by releasing water from the lake are expected to have minimal results — less than two inches reduction in the lake level.
Corps spokesman John Campbell said they will continue to assess the risks as the storm nears.
The culvert near Clewiston is one of 26 being replaced around the dike, he said.
The water control structure is complete, said Ms. Borochaner. She explained that the concrete culvert was cast in place, while a temporary coffer dam holds back the water. The backfilling of the excavation in the dike is underway but not complete, she said.
Other corps projects to reinforce the aging earthen berm around Lake Okeechobee do not pose risks to the dike during the storm because they do not involve breaches in the dike itself, she explained.
The Herbert Hoover Dike is a very long dam, she said — 142 miles of dam. The areas at greatest risk of breaching are in the southeast and southwest portions. The corps has prioritized repairs in those areas.