Sun Sentinel

October 04, 2016

 

Hurricane Matthew threatens to test Lake Okeechobee's dike

Andy Reid

http://www.sun-sentinel.com/local/palm-beach/fl-matthew-lake-okeechobee-threat-20161004-story.html

 

Inspectors are checking Lake Okeechobee's troubled dike and water managers are draining canals out to sea to try to lessen flooding threats as Hurricane Matthewchurns toward South Florida.

The swollen lake's water level is already higher than the peak range officials try to maintain. The heavy rainfall associated with Matthew could risk the stability of the 30-foot-tall mound of rock, shell and sand surrounding the lake.

"The lake at its current position is not comfortable but ... there's no immediate threat of failure," Army Corps of Engineers spokesman John Campbell said.

The Army Corps tries to keep the lake between 12.5 and 15.5 feet above sea level to ease the strain on the 143-mile long dike considered one of the country's most at risk of failing.

The lake level on Tuesday was 15.78 feet. Erosion problems and other stability threats are more of a risk when the lake level rises above 17.5 feet, according to the Army Corps.

The problem is, the lake fills up much faster than South Florida's vast system of canals and pumps can drain water out to sea. Just one tropical storm can boost the lake 3 feet.

Increased dike inspections, which started last month and continued Tuesday, are meant to identify spots where erosion threatens to allow water to burst through the earthen structure and flood lakeside communities.

Boulders and other materials already positioned near the lake are available to strengthen areas where inspectors find signs of wear or if damage occurs during a storm.

"The goal of the inspections is to identify any issues as early as possible (and) take any action possible to ensure the dike would not fail," Campbell said.

The Army Corps advised people living and working around the lake "to be prepared to take action should conditions warrant."

Evacuations of lakeside communities, such as Pahokee, Belle Glade and South Bay, could be called for if dike failures emerge or are considered imminent, but current conditions haven't required that, Campbell said Tuesday.

Lake Okeechobee's waters once naturally flowed south and replenished the Everglades. Now, after South Florida development and farming overtook half of the Everglades, an extensive network of canals, pumps and levees drains away much of that water.

The South Florida Water Management District since Friday has been draining canal water out to sea to get ready for the soaking Hurricane Matthew could deliver.

"We are trying to make room for storage of excess water," district spokesman Gabe Margasak said. "The key is to get ahead of it."

The district's 2,000 miles of canals are the regional flood-control arteries that collect water draining in from community canals.

The Lake Worth Drainage District, with canals in central and southern Palm Beach County, is one of the local drainage systems that sends water into the district canals.

The Lake Worth Drainage District's main canals started draining water at full capacity after heavy rains in Palm Beach County on Monday night and planned to keep it up as Matthew approaches.

Despite the preparations, Mother Nature can still deliver more rain than South Florida's canals and pumps can handle, said Tommy Strowd, Lake Worth Drainage District operations director.

"There always can be flooding, no matter what you do," Strowd said.

Water levels from Lake Okeechobee to the Everglades have been higher than normal this year due to a rainier-than-usual winter and spring preceding the summer-to-fall storm season.

Lake Okeechobee's dike, built in the 1930s, is in the midst of a decades-long rehab, which limits how much water can be held in the lake. The slow-moving dike repair is expected to take until 2025.