Dredging Helps Save Florida's Lake Panasoffkee from Itself
LAKE PANASOFFKEE, Fla. A 50-foot dredge being outfitted on the eastern shore of this 4,800-acre lake is an unlikely time machine.
The hulking assembly of welded steel plates, cables and a pair of mufflers taller than a house could return Lake Panasoffkee to its near pristine condition from when Theodore Roosevelt was president.
"We figure we're turning the clock back 100 years," said Lizanne Garcia, head of a water improvement program for the Southwest Florida Water Management District.
The Sumter County lake is slowly dying. It's choking from a simple, natural chemical reaction that drizzles a pencil-tip thick layer of sediment across its bottom every year.
The water management district is working to restore the lake.
A process that's been going on thousands of years, the slow accretion of sediment is covering the bottom, shrinking the lake and robbing fish of nesting sites.
Since the 1940s, 800 acres of the lake have vanished. Willows and red maples grow where once was open water.
Jim Veal Sr. has watched the lake shrink in the 50 years since he opened the Pana Vista Lodge on the western shore.
Veal, 73, said that since he first came to Panasoffkee, the trees and shrubs have crept a quarter-mile into the lake.
The sediment also covers the hard bottom of dead snail and mussel shells that bass and panfish need to make nests for their eggs. Though recreational fishing is still good, it has declined. The 13 fish camps that dotted its shore in the 1940s have dwindled to three.
Lake Panasoffkee's problem is not pollution, said Mike Holtkamp, head of the water district's restoration project.
"The water quality is excellent," he said.
Panasoffkee is a rarity among Florida lakes. It's fed by water seeping from the Floridan aquifer through numerous small springs and vents rather than rain running through its drainage basin.
"Basically, this is an outcropping of the Floridan aquifer," Garcia said.
The clear groundwater is rich in dissolved calcium carbonate picked up from the limestone that forms the underground sponge of the aquifer.
A chemical reaction causes the mineral to solidify and settle to the bottom in a chalky paste.
It piles up slowly, maybe an inch in 12 years. In some places, the sediment is more than 20 feet deep, nearly 3,000 years worth of accumulation.
The solution is to dredge the sediment down to the original shell bottom.
With a combination of money from the water district, the Florida Legislature, federal sources and the Florida Fish and Wildlife Conservation Commission, planning for the $25 million restoration project started in 1999.
An area covering about 22 acres was dredged in 2000 to test how well the lake would recover. It did recover, Veal said, and fishing immediately improved.
"That place turned into an aquarium overnight," he said. "The fishing was phenomenal. It still is."
When finished in January of 2008, the project will have moved a staggering 8.2 million cubic yards of sediment from the lake to a 400-acre area along Interstate 75.
Put that sediment on a football field from goal line to goal line and sideline to sideline and it would form a stack nearly a mile high.
Once the new dredge is ready to work, it will move along the shoreline in the project's next phase, sucking out half a backyard swimming pool of sediment and water a minute.
The crew will use Global Positioning Satellite receivers and computers to guide the underwater excavation.
In addition to restoration, the work will give waterfront homeowners better access to the lake.
The rising sediment makes water shallow enough for aquatic vegetation such as cattails and arrowhead to sink roots and grow along the shore.
Those masses of vegetation can break free and float in the lake.
Wind drives the floating masses to shore, engulfing docks and keeping boats from open water.
Crews will remove much of that vegetation, and the dredging will keep the plants from returning.
The small community of Lake Panasoffkee, mainly retirees and winter residents, initially was wary of the water district's project but now supports the plan.
"We're excited about it. At first we were very apprehensive," fish camp owner Veal said. The approval comes from a need to stop the lake's slow decline.
"You could see the shell bottom all along the lake," David Starnes said of Panasoffkee in 1959.
"It got to where you couldn't see any shells. It's absolutely necessary."
Source: Knight Ridder/Tribune Business News