Hurricane Ian: Army Corps, SFWMD lower canals into St. Lucie River, Indian River Lagoon

As South Florida falls into the crosshairs of Hurricane Ian, water managers are lowering canals and closing dams to make room for what could be over 6 inches of rainfall. 

The state agency tasked with overseeing water resources for over 9 million South Floridians started to lower canals, including three major waterways that cut through Martin and St. Lucie counties, officials announced Monday afternoon. 

The C-23 and C-24 canals, which feed stormwater runoff into the St. Lucie River, and the C-25 Canal, which connects to the Indian River Lagoon in Fort Pierce, were lowered, according to South Florida Water Management District spokesperson Sean Cooley.

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"We are preparing for Hurricane Ian by lowering our canals throughout the (district), which are the main arteries and highways to carry water away from communities," SFWMD Executive Director Drew Bartlett said. 

The SFWMD, which covers 16 counties in South Florida, and the St. Johns River Water Management District, which covers 18 counties in North Florida, are closing all state-managed navigational locks, campgrounds and properties until the storm passes. 

Army Corps: Lake O dam is safe 

The U.S. Army Corps of Engineers — tasked with managing Lake Okeechobee and preventing flooding in nearby communities — opened its emergency operations center Monday night. 

The staff Tuesday completed a pre-storm evaluation of the Herbert Hoover Dike, the 143-mile-long earthen dam around Lake O that protects surrounding communities from flooding, according to spokesperson Jim Yocum. 

"The dam is looking good," he told TCPalm. 

After hurricanes in 1926 and 1928 killed 2,500 people, the Corps built a north- and south-shore levee from 1932-1938. The agency since has expanded the levees to create today's Herbert Hoover Dike.

The dike "is safer today than it has ever been going into a storm," according to a Corps statement. "With the current lake level and the track of the storm, the Jacksonville district is confident that the (dike) will perform its purpose of safeguarding the lives and property of those living and working around the lake." 

A years-long rehabilitation project on the dike is 97% complete, according to the Corps. With Lake O under a Tropical Storm warning as of 2 p.m. Tuesday, all Corps structures along the dike will close by late Tuesday afternoon, and stay closed until the storm passes. 

Lake O's elevation above sea level was 13 feet, 2 inches as of Tuesday morning, according to the latest Corps data. That's over 2 feet lower than this point last year, after the start of South Florida's rainy season was abnormally dry. The region's coastline was still facing a "moderate drought" as of Sept. 20, according to the U.S. Drought Monitor.

"This provides us with more capacity than normal for this time of year," the Corps said in a statement. "While there are no absolutes, it appears favorable that the lake can take in the water from this storm without having to make large-volume releases." 

Still, the feds say "it is likely" they will release local basin runoff through the St. Lucie Lock and Dam, but those releases will not include any water from Lake Okeechobee, according to the Corps. 

The Corps plans to stop operating its federally managed locks — including the St. Lucie Lock and Dam in Stuart and the Port Mayaca Lock and Dam in western Martin County — when lightning is in the area or when winds exceed 35 mph. 

Currently, the St. Lucie Campground remains open, but if that changes, campers will receive refunds for any cancelled camping reservations. 

“Our staff is coordinating with state and local officials,” said Col. James Booth, Jacksonville district commander. “We are adjusting our operations to ensure the safety of those who use our facilities and our staff in Florida.”

Max Chesnes is a TCPalm environment reporter focusing on issues facing the Indian River Lagoon, St. Lucie River and Lake Okeechobee. You can keep up with Max on Twitter @MaxChesnes, email him at max.chesnes@tcpalm.com and give him a call at 772-978-2224.