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Toxic blue-green algae health alert at dam; Army Corps leaves it open as tropical storm threatens

W.P. Franklin Lock and Dam
WGCU file photo/Calusa Waterkeepers
Despite a health alert for high levels of toxic blue-green algae at the W.P. Franklin Lock on the Caloosahatchee River, just prior to the arrival of a rain-laden tropical system, the U.S. Army Corps of Engineers decided to leave the lock open while closing those around Lake Okeechobee

Despite alarmingly heavy concentrations of toxic blue-green algae at the W.P. Franklin Lock and Dam on the Caloosahatchee River on Friday, the Army Corps of Engineers said the dam will remain open to drain heavy rains from an incoming tropical system.

The Florida Department of Health in Lee County issued a health advisory Friday warning people and their pets to stay away from the area due to “the presence of harmful blue-green algal toxins,” the agency wrote. “The public should exercise caution in and around Franklin Lock.”

The tropical system was taking aim at Fort Myers on Friday evening, gaining strength, and was expected to become the first named tropical storm of the Atlantic hurricane season.

The Army Corps was closing all its locks and dams on Lake Okeechobee to secure the 142-mile-long dike ringing the lake. The South Florida Water Management District was doing the same with the locks and dams it controls.

The Army Corps decided to leave open the Franklin Lock, which is several miles downstream from the headwaters of the Caloosahatchee River, to drain the four-to-six inches of rain expected to fall from the storm and wash through thousands of homes, parking lots and canals in the Caloosahatchee watershed.

It was unclear if the Army Corps was aware that the health department issued the warning about the toxic algae bloom. It was also unknown if closing the Franklin Lock would keep the blue-green algae from flushing downstream.

The Army Corps did not respond to several emails and phone calls.

Anywhere from 5 to 10 inches of rain are forecast to fall this weekend on Lake Okeechobee’s surface, which spans 734 miles.

Five inches of rain would add nearly 64 billion gallons of water to the lake, or about 5% more water to the lake’s roughly 1.3 trillion gallons. Ten inches of rain would add almost 128 billion gallons, or 10% more.

“We are encouraged because the lake is in a very good place right now at 12.59 feet,” said Lt. Col. Todd Polk, Jacksonville District deputy commander for South Florida. “We also have a Herbert Hoover Dike that is better prepared than it’s ever been before.”

The Army Corps said it would not release any water from Lake Okeechobee prior to the tropical system’s arrival, and it will close all structures along the Herbert Hoover Dike, which has been undergoing a renovation and strengthening effort since 2000.

When a tropical storm is expected to travel over the lake, the Army Corps secures the dike by closing it up to keep any storm surge inside the largely earthen embankments and prevent water from gushing into surrounding communities.

That will ensure that none of the water coming down the Caloosahatchee River during the storm came from inside the lake, which is chronically laden with blue-green algae like the water by the Franklin Lock on Friday.

The Army Corp has faced harsh criticism in the past when releasing water from the lake filled with blue-green algae, which is a sign of major nutrient pollution.

Most often created from excess fertilizer used in agriculture and on residential lawns being washed into waterways, nutrient pollution fosters blue-green algae and feeds red tides in the Gulf of Mexico.

After the storm passes, the Army Corps will inspect the dike before re-opening any structures. If they need to release any of the water that collected in the lake, the agency will let everyone know beforehand.

Environmental reporting for WGCU is funded in part by VoLo Foundation, a non-profit with a mission to accelerate change and global impact by supporting science-based climate solutions, enhancing education, and improving health. Sign up for WGCU's monthly environmental newsletter, the Green Flash, today.

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