Rapidly rising Lake O increases likelihood of releases to coastal estuaries

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JACKSONVILLE — If Lake Okeechobee, at 15.1 feet above sea level on Friday, continues to rise, the U.S. Army Corps of Engineers may start releases to the St. Lucie and Caloosahatchee rivers.

Lake Okeechobee rose by about 1 foot in the past month, Col. Andrew Kelly, commander of the U.S. Army Corps of Engineers Jacksonville District, told reporters in a telephone media conference on Friday, Sept. 18.

“It has been a pretty interesting season for us who have been dealing with this,” said Kelly.

“We began wet season with everything very, very, very dry,” he said. “We were trying to conserve water the best we could. As of today, with a foot of rise in the past month, we are looking at the need to make releases to the estuaries probably soon,” he continued. Soon ... but not yet.

“We made the decision this week not to execute releases,” Kelly explained. Next week’s decision might be different.

“Everything below the lake is just full,” he said. “There isn’t a whole lot of room to move water south of the lake.

“The South Florida Water Management District has been doing some very good work to find places to put water to hold some capacity so there is room to move some water south,” he continued. “Their efforts made it possible not to release this week.”

Kelly said no water from the lake has been released to the St. Lucie River since March 2019. Since the wet season started, most of the water released through the Franklin Lock on the Caloosahatchee River has been local basin runoff. This past week, all of the flow to the Caloosahatchee was local basin runoff, he added. The seven-day average flow at the Franklin Lock was 4,500 cubic feet per second (cfs), all basin runoff.

He said the corps is keeping a close watch on the six storms in the Atlantic, even though none of them appears to be of any imminent risk to the state.

“There is a lot happening right now,” said Kelly. “With the current situation on the lake and the rate of rise, it seems likely we will have to make releases, but we are not there yet.”

Kelly said he will schedule another press conference for Thursday and Friday and will likely hold weekly press briefings about lake conditions throughout the rest of the wet season.

The chief concern is the rate of rise, he said. “We are OK right now. There is not a lot of risk to the surrounding population at 15.1 feet. It’s all about the next set of storms.”

The colonel said the first hurricane is not the cause for concern. But if a storm dumps enough rain (as Irma did) to quickly raise the lake level by 3 feet, and another storm hits before there is time to get the lake level down, the danger of a breach of the Herbert Hoover Dike is increased. “If a storm like Irma puts 3 feet on the lake and then something rolls in behind it ...”

“We are just about in the middle of peak season for hurricanes,” he said.

Whether the corps will start lake releases depends on Mother Nature.

If the rate of lake rise slows, and they can push some water south, that can build some capacity for the next rain event.

Kelly said while repairs to the Herbert Hoover Dike aren’t complete, the dike is in better condition than it was in 2017. The project is on track to be completed in 2022.

“We have good, solid understanding of the dike,” he said. “We understand what it can handle.”

He said future decisions about lake releases will be based on rate of rise, rate of recession and the need to get water out.

He said couple of weeks of dry weather that allows transpiration could change the situation.

“One thing we can’t do this late in the season is to put people at risk due to flooding,” he added.

Kelly said if there are algal blooms on the lake near the water control structures, that may also be a factor.

Currently there are no algal blooms near Port Mayaca (where the lake connects to the St. Lucie Canal) or near Moore Haven (where the lake connects to the Caloosahatchee River).

“Certainly we will be paying attention,” he said. “It will have an influence in our decision-making. but if it comes to we have to move water out of Lake Okeechobee to avoid flooding, we will move water.”

Kelly said the state has doubled the amount of water monitoring.

“It’s building our knowledge and it’s building our understanding so we can build our knowledge about algae,” he said.

“We have a pretty good understanding of what is happening in real time.”

He said they will use the current science to be able to anticipate what is happening. “If there is an algae mat up against this structure, you don’t release,” he said. If there is no algae and the science indicates bloom potential is increasing and releases will be needed soon, they might release early.

“The real trick is figuring out the science,” he said. “That is why Florida has the Blue-Green Algae Task Force and the corps has the Engineer Research and Development Center (ERDC).

“What’s the bloom potential, how does it bloom, why does it crash, how to pick it up or dispose of it – there are a lot of smart scientists working on it,” he explained.

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