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Corps announces dry-season releases from Lake O

By Staff | May 7, 2020

The U.S. Army Corps of Engineers, Jacksonville District, on Friday made two advances officials say will lead to improved water quality in Florida now, and in the future.

The Corps announced it will increase flows from the W.P. Franklin Lock and Dam to the Caloosahatchee estuary at a 7-day average rate of 650-cubic-feet-per-second.

Recent rainfall has given a boost to conditions throughout the system, according to a Corps release. That rainfall may be here to stay in some capacity shows the NOAA’s one-month outlook for May.

“Last week, Lake Okeechobee received almost two inches of rain, and parts of the Kissimmee basin to the north of the lake received close to three inches,” said Col. Andrew Kelly, Jacksonville District commander, in a statement. “The other good news is that NOAA just issued their updated one-month outlook for May, which shows higher chances of above normal rain for most of the State of Florida. Typically, the wet season begins by mid- to late May, so we are in a better position right now to be able to provide a little more water to the Caloosahatchee to help maintain favorable salinity conditions in the estuary.”

According to Corps’ website, Wednesday’s lake stage is 11.29 feet NGVD. Corps officials said they will continue to monitor conditions closely and adjust flows as necessary. Any changes in flows to the estuaries will be announced to the public.

Sanibel-Captiva Conservation Foundation Natural Resource Policy Directory Rae Ann Wessel said these releases were a long time coming and are critical for marine life and water quality.

“Basically, for the past five weeks, the Caloosahatchee estuary is the only one that has been subject to water cut backs when we are the smallest user,” she said. “All other water users have been receiving all the water they want/need. The harm that causes to the estuary is that salinities rise in the upper estuary, making it too salty for the freshwater habitat that is critical to fish, crab, shrimp, shellfish, manatees and small tooth sawfish.

“Lack of flow at this time of year can also cause blue-green algae to bloom upstream of the lock.

This schedule will remain in effect until further notice, the release states. Additional runoff from rain in the Caloosahatchee and St. Lucie basins could occasionally result in flows that exceed one or both targets. The Corps will continue to closely monitor conditions and coordinate with its partners at the South Florida Water Management District to reevaluate releases weekly.

Flows to the St. Lucie estuary remain at zero cfs as measured at the St. Lucie Lock and Dam (S-80). Releases will be made in a pulse pattern beginning on Saturday.

“We remain optimistic about entering the wet season at a reasonable lake level, and will continue to balance the system, providing additional flows west to help estuarine ecology while continuing to carefully monitor conditions in coordination with our partners at the South Florida Water Management District, as they move forward with their initiatives to conserve water and mitigate water supply concerns,” Kenny continued in his statement.

SCCF Marine Laboratory Director, Dr. Eric Milbrandt, said these releases to the Caloosahatchee during the dry season are instrumental to the ecology of the water and the species that inhabit it.

“Providing freshwater flows during this time of year is essential for the health of the Caloosahatchee and the species that depend on it,” Bilbrandt said.

The Caloosahatchee is an estuary where fresh and saltwater mix. Much of the marine life need low salinity zones to complete their life cycle.

Milbrandt used the example of snook. He said they can be found in freshwater tributaries as juveniles to avoid being eaten by other predators.

Also, blue crabs. Milbrandt said the males need low salinity and females migrate up and down the salinity gradient.

“When there is insufficient rainfall within the Caloosahatchee watershed, freshwater flows from Lake Okeechobee can be used to maintain the salinity balance,” Milbrandt said. “Decisions about when and how much water can be used for this purpose is weighed by water managers based on the Lake levels, existing users of water, and the climate forecast. The SCCF measures salinity throughout the estuary along with dissolved oxygen, temperature and several other water quality parameters and provides a summary report to the U.S. Army Corps of Engineers and the South Florida Water Management District every week with the condition of the Caloosahatchee and recommendations on water flows.”

For those who wonder about releases and algal blooms, currently, NOAA and NASA satellite imagery indicates a low to moderate risk of algal bloom potential on the northern shores of Lake Okeechobee.

Herbert Hoover Dike awarded final contact on cutoff wall

According to a release Friday, the ACOE Jacksonville District awarded the final contract for the cutoff wall required as part of the continued rehabilitation of the Herbert Hoover Dike surrounding Lake Okeechobee.

“The award of the final cutoff wall contract is a significant milestone toward reaching the goal of having Herbert Hoover Dike construction complete by the end of 2022,” said Tim Willadsen, Herbert Hoover Dike Rehabilitation Project Manager, in a statement. “There is a lot of ongoing construction currently, which includes 10 culvert replacements and more than 35 miles of cutoff wall installation, including this last cutoff wall contract award.”

The Corps awarded the contract on April 30 for $41.4 million to Bauer Foundation Corporation from Odessa, Florida. According to the release, the contract calls for the construction of 4.1 miles of cutoff wall through the HHD embankment near Lakeport, Florida. Work on this project is expected to be complete by the summer of 2022.

“So far, we’ve completed 21.4 miles of cutoff wall in Reach 1, finished the Reach 1 cutoff wall gap closure construction, replaced 18 culverts, and removed or abandoned 4 culverts,” Willadsen said.

The release states that since 2001, the Corps has made a significant investment of more than $1 billion in projects designed to reduce the risk of catastrophic failure of the aging structure, with the estimated total cost of the rehabilitation effort to be more than $1.8 billion. The HHD project is fully funded to completion with the Fiscal Year 2019 President’s Budget, the State of Florida’s $100 million contribution and inclusion in the Supplemental Long-Term Disaster Recovery Investment Plan.

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