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Army Corps Starts Lowering Lake Okeechobee Heading into Dry Season
The Caloosahatchee River and Estuary receives freshwater from two sources — watershed runoff, which largely comes from precipitation, and Lake Okeechobee releases. Learn more >>
On Saturday, Oct. 26, the U.S. Army Corps of Engineers, Jacksonville District began using the operation flexibility inherent in the Lake Okeechobee System Operating Manual (LOSOM) to start releasing water from Lake Okeechobee into the Gulf Coast for the first time since mid-June. Under LOSOM, the Corps is aiming to release an average of 2,000 cubic feet per second (cfs) to the Moore Haven Lock and Dam (S-77).
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The Corps aims to use these discretionary releases to lower the lake by the end of dry season. These releases should build more resilience into the lake prior to the next wet season, and provide much-needed flows to the Caloosahatchee Estuary during the dry season, when watershed runoff is not enough to meet the demand.
In May, the lake entered the rainy season at around 13.7 feet, with enough capacity to absorb water from summer rains and what was predicted to be an extremely active hurricane season. As of Oct. 28, the lake was over 16 feet. This height is detrimental to the lake’s ecology, hindering the growth of submerged aquatic vegetation and preventing essential filtration to the ecosystem.
“Instead of rising instantly from 2024’s sequence of tropical storms and hurricanes — as the lake has done in the past with storms like Hurricanes Ian and Irma —lake height rose gradually over the season,” said SCCF Policy Associate Allie Pecenka. “Regions like Apalachicola and Tampa Bay saw torrential rainfall during Hurricanes Helene and Milton, while areas feeding directly into Lake Okeechobee remained relatively drier.”
Watershed runoff to the estuary has remained high over the wet season, lowering the water’s salinity. The 14-day average flow of water entering the Caloosahatchee, measured at the Franklin Lock and Dam (S-79), has fluctuated between the stress and damaging thresholds for approximately the past 130 days. Runoff has since tapered off to around 700-900 cfs (optimum flows are 750-2,100 cfs), which gave salinity a short break to recover.
What Does this Mean for the Estuary Going into Dry Season?
With the official end of hurricane season on Nov. 30, “we must remain vigilant for impacts to the lake and estuary a while longer but can then begin looking ahead,” Pecenka said.
Water managers are formulating their dry season strategy, which includes minimizing hazards associated with lake height, weighing input from various stakeholders, and considering the health of Lake O’s ecology.
“As we enter the dry season, SCCF’s primary concerns are protecting the health of the Caloosahatchee River and Estuary and the species inhabiting these ecosystems,” Pecenka said. “Inherent in these goals are ensuring the estuary receives enough freshwater.”
As we move out of the wet season, conditions become more favorable for red tide (Karenia brevis) and harmful algal blooms. K. brevis has recently been detected in various concentrations offshore of Southwest Florida. By drawing water out of the lake in these smaller releases, the Army Corps hopes to avoid the larger releases that are more likely to exacerbate a red tide bloom later in the season.
SCCF will continue to monitor this potential development and will advocate against nutrient-rich releases during active red tide and other HABs.
Stay Up to Date
Stay informed on this nuanced situation, which has wide-reaching impacts on water quality, our economy, wildlife, and quality of life, by subscribing to SCCF’s water conditions updates and exploring the resources below.