Dike Along Huge Florida Lake Is Leaking
for National Geographic News
|March 10, 2006|
About 2,500 people died in 1928 when water from Florida's Lake
Okeechobee inundated their communities during a hurricane, making it one
of the worst natural disasters in United States history.
Today the earthen barrier of Herbert Hoover Dike140 miles (225 kilometers) long, 35 to 50 feet (10 to 15 meters) highstands between area residents and the nearly Rhode Island-size lake.
Hurricanes have crossed or passed near the lake since the 1928 disaster. None of the storms has penetrated the massive dike or pushed water over its top. (See an interactive feature on hurricanes.)
But the dike has begun to leak.
The U.S. Army Corps of Engineers first noticed the problem when inspectors found evidence of "seepages" in the 1980s, according to Jacob Davis, a civilian engineer in charge of repairs.
The leaks are caused by water under constant pressure pushing against the dike, loosening soil, and gradually seeping through. As the water level rises, it exerts more pressure on the dike, and the seepage can worsen and cause the dike to fail.
"Water flows through the ground naturally," Davis said. "At every dam site around the world, seepage occurs. The water tends to move through gravel or clay and sand."
As the water moves, it finds larger openings and follows the paths of least resistance, Davis said.
Engineers are currently repairing a 22-mile (35-kilometer) section of the dike on the lake's eastern shorepart of a years-long effort to restore the dike.
About 40,000 people now live in lakeside towns such as Okeechobee, Pahokee, Belle Glade, and South Bay.
The dike, always looming somewhere in the background, has become part of life by the lake. But residents haven't forgotten the long-ago catastrophe.
A sculpture at the Belle Glade public library depicts a young family of four fleeing the flood, looking up at the wall of water that is about to engulf them.
"We always try to remember to honor those who lost their lives in the '28 storm," said Brenda Bunting, executive director of the Belle Glade Chamber of Commerce.
Work started on the Herbert Hoover Dike in the early 1930s after a much smaller levee collapsed during the catastrophic hurricane of September 1928.
Some compare attempts to control the waters of Lake Okeechobee to grabbing the tail of an endangered Florida panther. The leaks and recent active hurricane seasons have caused lakeside residents to keep a closer eye on the dike.
Bunting said there was more uneasiness as Hurricane Wilma headed toward the lake in October 2005.
The dike held, but residents still got a dramatic reminder of the power of wind and water.
Charles Corbin owns Slim's Fish Camp, a restaurant his father opened in 1935 on Torrey's Island, a small island in the southeastern corner of the lake.
Corbin said a wind-driven storm surge put his restaurant under about seven feet (two meters) of water.
"The surge came across the lake like a tidal wave or a tsunami," Corbin said. "It went up real fast and went right back down."
The business owner doesn't think the dike is likely to fail because of a hurricane, unless the storm stalls over the lake.
"Hurricane Wilma stayed only about four hours," Corbin said.
"If a hurricane stalled and stayed a day or so, you might have problems."
Could Tragedy Strike Again?
Scott Hagen, an engineering professor at the University of Central Florida in Orlando, said it's unlikely the dike will fail because of a hurricane.
"If they keep the water at the appropriate level in Lake Okeechobee, the chances of having water surging up and over the dike are very, very low," he said.
But it's not out of the question. If a tropical storm dumped several feet of rain over Florida, the water level in Lake Okeechobee could rise dramatically, Hagen said.
And if a hurricane with winds of 120 miles an hour (190 kilometers an hour) or more crossed the lake a few days later, "I could envision the water overtopping the dikes," he said.
"Would the dikes hold up if that happened? There's no way of knowing," Hagen said.
South Bay City Manager Tony Smith said people around the lake are relieved that the U.S. Army Corps of Engineers is working on the dike, especially after Hurricane Wilma's visit.
According to Smith, the storm dumped so much debris into the lake that it clogged the intake where South Bay draws its drinking water.
"There was seven to ten feet [two to three meters] of debris on our shores," Smith said.
"It's a relief to know that that dike will be secure. It would blow your mind to know what was taken out of that intake."
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