Our subscribe page has moved!

Please visit baysoundings.com/subscribe to submit your subscription request.

And So It Flows
New Bridge at Ft. DeSoto Restores Tidal Flow Eliminated by Causeway

With one final scoop of sand, excavators pulled the plug on a barrier separating two embayments at Ft. DeSoto Park, nearly 50 years after causeway construction severed the arteries. Dozens of well-wishers celebrated the berm-busting last November from atop a new 40-foot bridge erected to restore east-west circulation to the semi-enclosed bays.

The free-flowing tides are expected to revive the once-flourishing ecosystem.

Moments prior to opening the waterway, officials discharged buckets of nontoxic, fluorescent dye so scientists could trace the tidal movement and exchange of water. The Technicolor brew, a vibrant ribbon of lime green and orange, gave onlookers their first glimpse of a gently pulsing current exploring new territory.

The aquatic restoration project is the result of a collaborative effort between Pinellas County and several regional and national funding partners, including the Southwest Florida Water Management District, National Oceanic Atmospheric Administration, U.S. Environmental Protection Agency's Gulf of Mexico Program, Pinellas County Environmental Fund and the U.S. Fish and Wildlife Service. The University of South Florida and Eckerd College also are partners.

Partial replacement of the causeway and construction of the $1.6-million bridge were necessary to allow the free flow of water from the Gulf of Mexico back into the park's waterways.

"Unless you had an extreme tide or high wind, that embayment never really got any flushing," explains Eric Fehrmann, Pinellas County environmental manager. Robbed of dissolved oxygen, it became a stagnant pool nearly devoid of sea life in summer months when water temperatures climbed as high as 106 degrees.

"You have this area that most of the time looks nice, but it's an empty house," says Tom Cuba, whose company, Delta Seven, was tapped to evaluate pre- and post-restoration conditions.

Cuba has more than a passing interest in the project. As a graduate student, he studied Ft. DeSoto in the late 1970s, and was later hired by Pinellas County, which was conducting a study of the park's package sewage treatment plants. "What we learned was that the package plants really didn't have a whole lot of impact on water quality, but the closure of that area did."

When the package plants were closed and water quality remained poor, the county was finally able to finger the culprit. Having pinpointed circulation as the problem, it began evaluating options.

The county first floated the idea of installing a series of twin 9-foot box culverts, but engineering analyses confirmed the need for something to accommodate stronger flows. The proposed solution was two 40-foot bridges, one on the main road and a second on the maintenance road, but cost constraints ultimately tipped in favor of a single bridge.

Lurking in Limestone

One of the best features of the new bridge are the critters - and critter spectators - it's expected to draw.

County officials say the channel's limestone lining is bound to attract fish and other bottom dwellers that had been avoiding the area because of the muck, heat and lack of seagrass. "I'm betting there will be sheepshead, snook and reds on either end of the bridge lurking in the shadows waiting for little fish to be swept through," says Fehrmann.

Mackerel and black mullet already have begun taking up residence, and a 33-inch snook was caught off the bridge just weeks after the waterway's reopening.

The bridge is also canoe and kayak friendly. Even on an extreme high tide, notes Fehrmann, there should be about four feet of clearance under the bridge, providing yet another magnificent backbay environment for paddlers to explore.

© 2004 Bay Soundings
www.baysoundings.com