JACKSONVILLE – This summer could bring more and larger algal blooms on Lake Okeechobee, according to Col. Andrew Kelly, commander of the U.S. Army Corps of Engineers Jacksonville District.
In a May 7 media call, Kelly said algal blooms are one of the factors they keep in mind when determining releases from Lake Okeechobee to the Caloosahatchee River and St. Lucie River.
The corps made no changes to the release schedule this week. There is no flow at the St. Lucie Lock to the St. Lucie River. Flow to the Caloosahatchee River, measured at the Franklin Lock, is capped at 2,000 cubic feet per second (cfs). This flow includes water from the lake and local basin runoff.
“Today the lake is at 13.87 feet, about .38 lower than a month ago, but we are still sitting 2.5 feet higher than we were last year,” Kelly explained. “Releases south of the lake are around 2,700 to 2,800 cfs.”
“For this next week, we are not changing our operation,” he said.
“In the dry season the Caloosahatchee absolutely needs water from Lake Okeechobee,” Kelly explained. “2,000 cfs is a little high on the beneficial range, but it’s ecologically OK.”
While no lake water is going east, water that falls in the C-44 basin may flow into the lake.
That’s good news for the St. Lucie estuaries, he added.
The colonel said since the lake is below 14 feet, “it allows us to manage the C-44 canal via Lake Okeechobee,” he explained. “If there is additional basin runoff, we can take water onto the lake rather than opening the S-80 (St. Lucie Lock).”
He said the water allowed to backflow from the C-44 would not equate to a significant volume of water on the big lake, but the freshwater flow could harm the estuaries if allowed to flow through the St. Lucie Lock.
For the past seven days, an average of 150 cfs has flowed from Lake Okeechobee to the C-44 canal at Port Mayaca in order to maintain the level of that canal for navigation and water supply.
The level of the C-44 canal is usually maintained around 14 to 14.5 feet above sea level. On Friday, with the lake below 14 feet, the canal was 13.62 feet.
Lake releases to the canal depend on rainfall in the basin. “If the canal gets too low, the source of the water becomes the lake,” Kelly said.
“There is water use for that canal so there is water drawn for that canal. We keep that canal at a certain level in accordance with the way we manage the overall system,” he explained.
Kelly said the slow recession rate of the lake this year has been good for the endangered snail kites. “We’ve got 134 snail kites nesting on the lake,” he said. The birds nest in the marshes above the water, and if the area under the nest dries out too soon, it makes it easier for predators to attack the young.
“We will continue to focus on trying to get as much water out of the lake as we can because we are still a little bit high,” Kelly said. “As the wet season ramps up, that is going to decide when or if we begin high level releases.”
He said predicting possible releases would mean “applying a lot of subjectivity based on what we think Mother Nature is going to do in and around the lake.”
“May is very tricky,” he said. “We’ve had things where significant rainfall happened and changed the lake stage pretty significantly.”
Kelly said algal blooms will be a factor that will be considered in future decisions on lake releases.
“We’re above average on algae on the lake,” he said. “We’re 100 percent tracking what is going on. Based on what we have seen recently, we anticipate a higher level of algae on Lake Okeechobee this summer."
“It’s completely weather dependent,” Kelly added. Hotter weather will mean more algae.
“Algae grows all over the place. It’s not just a Florida problem,” he added.
“When there are those conditions present, it does factor into our decision making,” he said.
He said the USACE lab in Vicksburg, Miss., is studying algae and what can be down on the scale of Lake Okeechobee and Lake Erie. He said they are working with other academic institutions. In addition, task forces are focused on blue-green algae and red tied in Florida.
Kelly said releases to the estuaries may be needed later in the summer, especially if hurricanes are approaching. “Releases into both the St. Lucie and the Caloosahatchee are part of how Lake Okeechobee and the overall system works, by the way it was built and designed in the past, those are the tools we have,” he said.
Projects planned and those already under construction can help prevent harmful releases. “We’re looking at storage north of the lake,” said Kelly.
“That would have an impact on how we manage Lake Okeechobee.”
The first contracts on the Everglades Agricultural Area (EAA) reservoir should start by the end of this year. The EAA reservoir will also have an impact on how the lake is managed, he said.
“Infrastructure we are building across south Florida in the future will optimize how we manage the system holistically,” he said.