Lake Okeechobee continues to rise after hurricane

OKEECHOBEE — As runoff from Hurricane Irma continues to drain south through the Kissimmee River basin, the level of Lake Okeechobee is rapidly rising.

The week before the storm hit, the lake level was 13.5 ft. (above sea level).

Just a week after the storm made landfall, the lake had risen 2 feet.

On Tuesday, the lake level was 15.66 ft.

According to the U.S. Army Corps of Engineers, water is flowing into the lake at a rate of about 42,000 cubic feet per second (cfs). That’s about 18.8 million gallons of water per minute, or 27 billion gallons per day.

The Corps expects the flow to drop to 30,000 cfs by next week.

The day before Hurricane Irma hit, all of the Lake Okeechobee gates were closed. Right after the storm, there was too much flooding around the lake to release any lake water, although water continued to pour in from the Kissimmee River.

On Friday, Sept. 15, the Corps began releases to the C-44 canal at Port Mayaca, ranging from 2,000 to 4,000 cfs, depending on capacity available.

The canal’s available capacity for lake water depends on the direct basin flow into the canal. Over the first four days of releases, about 4.1 billion gallons of water flowed from the lake into the C-44, or about 1 billion gallons a day.

Earlier in the wet season, the water at Port Mayaca was flowing the other direction, with flow from the C-44 going into the lake. During the wet season more than 24 billion gallons of water from the C-44 flowed into the lake.

East of the dike, at the C-10A structure which is south of Port Mayaca, water is flowing into Lake Okeechobee at about 672 cfs, to relieve flooding in that area Martin County.

On Tuesday, Sept. 19, the Corps started releases from the lake into the Caloosahatchee River at Moore Haven, of 2,000-4,000 cfs, depending on capacity. Most of the flow to the western estuaries are still from basin runoff.

On Monday, basin runoff flow averaged 9,962 cfs.

South of the lake, water is being backpumped from the areas near Belle Glade and South Bay, at around 4,000 cfs., by the South Florida Water Management District to alleviate flooding in the towns just south of the dike. The backpumping is expected to cease by the end of the week.

“We still have high water levels in the canals around the populated areas of Belle Glade and South Bay,” explained SFWMD spokesman Randy Smith.

“When the pumps are not running the water levels are climbing back up due to the saturation in the EAA. We do see that changing as the last few days have been very hot and dry. If this continues the district hopes to bring water levels down to levels that do not pose a safety threat to families and businesses in the area and cease pumping operations asap.

Corps data shows the Everglades Agricultural Area was flooded by the hurricane, and the water conservation areas south of the EAA are full, so no water can flow south from the lake.

Laureen Borochaner, Chief of Engineering for the U.S. Army Corps of Engineering Jacksonville District, said the Corps had inspectors in place before the hurricane hit, and started dike inspections as soon as the hurricane winds subsided. The dike suffered only minimal erosion from the hurricane, she said.

As the lake level rises, the inspections will continue; the higher the lake level, the more frequently it will be inspected.

“When we hit 15.5 at the lake, we see increased risk of seepage or piping,” she explained. She said they will pay special attention to known weak points in the dam in order to ensure there are no issues as the lake rises.

Historically, they have seen “signs of distress” when the lake hits 17 ft.

Hurricane Maria, expected to pass to the east of Florida, could cause the releases to the C-44 to slow or stop.

Lake levels above 16 ft. could endanger the Herbert Hoover Dike – a 143 earthen berm around the lake. However, in recent years, the Corps has addressed issues at the dike’s weakest points, which are on the south side, where land elevations are lower. About 21.4 miles of cutoff wall has been constructed, with about 35 miles to build.

During Hurricane Irma, a storm surge of about 7 feet was recorded on the north shore of the dike at the Lock 7 Recreation Area. Since the lake was only around 13.7 ft. when the hurricane hit, the storm surge was not a problem for the Lock 7 pier, which is about 24 ft. above sea level at the walkway. The floor of the Lake Okeechobee Scenic Trail trailhead restroom at Lock 7 is about 22 ft. above sea level.

 

This is Lake Okeechobee at Lock 7 pier in Okeechobee on Sept. 19, 2017, shortly after Hurricane Irma. The deck of the walkway is at 24 ft. above sea level as compared to the 15.66 ft. above sea level the lake has risen to since the hurricane.

Publisher/Editor Katrina Elsken can be reached at kelsken@newszap.com

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