South Florida water managers are increasing inspections of the Herbert Hoover Dike as Lake Okeechobee swells with summertime rains.
The lake stood at 15.57 feet above sea level Thursday, triggering the unwelcome release of more water into the Caloosahatchee and St. Lucie estuaries, as well as boosting reviews of the dike’s vulnerable south side.
John Campbell, a spokesman for the U.S. Army Corps of Engineers, said once-monthly inspections will increase to twice per month. If the lake reaches 16 feet, weekly inspections will be triggered.
“There is no imminent danger of the dike failing,” Campbell said. “Our concern is a heavy rain event that causes the water to jump 3 feet before we can open enough outflow to get rid of it.”
The Herbert Hoover Dike, a 143-mile barrier built in the 1930s with shell, gravel, rock and limestone, protects Glades-area communities from flooding. To minimize pressure on the dike from the trillions of gallons of lake water, the corps prefers to keep Lake Okeechobee between 12.5 and 15.5 feet above sea level.
But getting water out of the lake primarily means sending it east into the St. Lucie Estuary and west into the Caloosahatchee River.
The fresh lake water is damaging to the brackish marine life of the estuaries and was blamed for seeding an immense algae bloom in June and July that covered Treasure Coast waterways with inches-thick green muck.
On Thursday, the corps said it would have to increase the lake releases by 53 percent on the St. Lucie side to an average of 807,900 gallons per minute. The Caloosahatchee will get a 42 percent increase in lake water that equals an average of 1.8 million gallons per minute.
“We expect the water level to continue to rise over the next few weeks,” said Candida Bronson, acting operations division chief for the Jacksonville district of the corps. “Increasing flows from the lake now allows us to slow the rise to put us in the best position to handle heavy rain events that might develop in the final weeks of the wet season.”
South Florida’s wet season usually lasts into early to mid-October. In February, record rainfall pushed the lake to 16.4 feet above sea level, the highest it had been since 2005 in the aftermath of Hurricane Wilma.
Campbell said the lake rose nearly a quarter of a foot over the past week. The natural tilt of the water pushes it south, so that’s the area of the dike that’s most closely watched.
“It’s susceptible to seepage and erosion, which is what we are trying to avoid,” Campbell said.
Businesses that suffered through the Fourth of July weekend with thick, stinky algae mats turning off tourists are concerned the increase and flows could trigger another outbreak.
Mary Radabaugh, manager of Central Marine in Stuart, said Thursday she had to shut down operations for several days during the worst of the algae bloom.
“There is a possibility of it returning if our temperatures stay warm enough and we have enough nutrients going into the water,” she said. “All of us had symptoms from being near it — itchy, watery eyes, headaches at night.”
An algae bloom on the lake once covered roughly 200 square miles, but Randy Smith, a spokesman for the South Florida Water Management District, said it has since mostly dissipated.
Heavy rains on the lake and shorter days may have contributed to the reduction, Smith said.
“There is nothing visible as far as algae on the lake,” he said. “If the temperatures are down just a couple of degrees, it can make a difference.”
The corps also announced Thursday it had awarded a $27.7 million contract to a Jacksonville company to replace water control structures at the dike.