Zombie Estuaries 2021: St. Lucie, Caloosahatchee to be dumping grounds
Lake Okeechobee discharges began March 6, 2021. Why this will lead to another summer of horrific water quality downstream.
Ed Killer, Wochit
Federal water managers slowed releases to both the Caloosahatchee and St. Lucie rivers over the weekend in an effort to slow Lake Okeechobee’s recession rate.
Average flows to the Caloosahatchee were 2,000 cubic feet per second, but the Army Corps lowered that to 1,200 cubic feet per second, and levels in St. Lucie were dropped to 300 cubic feet per second, according to U.S. Army Corps of Engineers records.
“It’s a good number,” said Barry Rosen, a professor with Florida Gulf Coast University’s Water School, talking about the flow to the Caloosahatchee system. “Twelve hundred (cubic feet per second) is not going to harm oysters, and it’s not going to hurt the freshwater tape grasses.”
The Army Corps has tried for several weeks now to lower Lake Okeechobee, which was just over 14 feet above sea level Wednesday afternoon, in order to avoid summertime releases.
Blue-green algae often forms on Lake Okeechobee during the summer, and past summer releases have caused massive blooms in the Fort Myers-Cape Coral area.
“If there’s a bloom, and that’s a random event, they could be preventing that as well,” Rosen said.
Lower water levels mean more habitat
The Army Corps had to slow the releases to lessen the impacts to protected species like the snail kite, which needs specific water levels in order to nest.
“They’re starting to use the lake a lot more,” said Paul Gray, with Audubon Florida. “These are the levels where they can really get out and feed. It’s 150,000 acres of habitat that’s become available (with the lower water levels).”
Gray said the crux is trying to lower the lake at a rate that doesn’t harm the birds, which is a balancing act given the offsetting needs.
“We really need to get the lake down before this summer because we’re going into summer, and they’re really in between a rock and a hard place,” Gray said of water managers. “Ideally by June 1 we get to 12 feet, but we’ll probably be at 13 or above.”
Dry season discharges
The releases this dry season were approved as part of an operational deviation that was approved in September.
The deviation allows the Army Corps to sometimes release water during the dry season in hopes of avoiding Lake Okeechobee summer discharges, which are often tainted with blue-green algae.
The deviation requires the Army Corps to take no more than a half-foot per month off the lake to avoid harmful ecological impacts.
“We constantly monitor conditions around Lake Okeechobee, and as evapotranspiration and dry conditions have accelerated the lake recession, we are reducing our releases to protect the nesting birds that have returned to the lake in large numbers for the first time in several years,” said Col. Andrew Kelly, Jacksonville district commander and top Army Corps officer in Florida.
He said the lake is still too high for this time of year, but that the agencies had little flexibility when it came to this decision.
“The lake is higher than we would like, but we must try to balance the ecology of the lake as well as the northern estuaries as we make efforts to reduce the lake level before the onset of the wet season,” Kelly said.
The Army Corps says recent satellite images show conditions on Lake Okeechobee remain poor for development of large, harmful algal blooms at this point.
But Calusa Waterkeeper John Cassani said he’s seeing signs of algae in parts of the rivers.
He pointed to recent satellites imagery from the National Oceanic and Atmospheric Administration as reason to worry.
“The last NOAA satellite imagery, they reported a cyanobacteria index and they described it as 100 square mile potential,” Cassani said. “And (the Florida Department of Environmental Protection) sampled near the (W.P. Franklin Lock and Dam) and on their reporting they said they saw a cyanobacteria bloom but that the levels were pretty low.”
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