3 years ago

Sept Oct 2015 Marina World

The magazine for the marina industry


WATERFRONT DEVELOPMENTS Photo: Eric Hasert Building to survive a hurricane by Robert Wilkes Ft. Pierce on the Treasure Coast of Florida is a gateway to the Gulf Stream and some of the best sailfish fishing in the world. Ft. Pierce owns and operates City Marina in the Indian River, the central channel of the Intracoastal Waterway. The marina has two moorages: an inner marina of 108 slips with fixed-dock berths and a new, state-of-the-art floating-dock outer marina with 137 slips accommodating yachts from 40 to 140ft (12 to 43m). Ft. Pierce is a convenient favourite of many boating and fishing enthusiasts. Gulf Stream fishing grounds are typically 60 miles (95km) from Florida harbours, but City Marina requires just 12 to 20 miles (19 to 30km) of motoring before lines are in the water. The Florida Turnpike and nearby airports easily connect boaters to Ft. Pierce. Hurricanes and the Treasure Coast On the night of 30th July 1715, a twelve-ship Spanish treasure fleet departed Cuba bound for Spain. A powerful storm scattered the ships along the Florida coast. Eleven ships foundered and sank. Spanish coins and artefacts are still found, sometimes washing up on Florida beaches. Fast forward nearly 300 years to 2004. There were so many hurricanes the weather service exhausted its annual list of hurricane names. Florida was battered by Charley, Frances, Jeanne and Ivan. Jeanne was strongest, but the knockout punch that destroyed the City Marina on the night of 4th/5th September 2004 was Frances. Hurricanes typically pass over in five hours but Frances battered Ft. Pierce for 34 hours and held the marina in its high-velocity grip near the eye of the storm as gusts reached 108mph (173km/h). Before the hurricane, City Marina staff did all they could to protect the marina and its tenants, including adding more lines to each boat. Conditions were so violent that boats broke loose of their moorings. Incredibly, the marina remained intact for 28 hours. Then, as the hurricane finally began to move, the wind direction changed abruptly. The result was a powerful 20ft (6m) storm surge. The marina survived the winds but not the storm surge and, of the 97 boats in the marina, 96 were lost. The lone survivor, a trawler named Shameless, was blown offshore and 38 - September/October 2015 MW2015SepOct.indd 38 05/09/2015 14:12:24

WATERFRONT DEVELOPMENTS somehow dropped its anchor. The owner put in the key and drove it away. Recovering from the devastation Boating and tourism are important to the city’s economy. City Marina paid for itself and the surplus helped to fund civic improvements. When City leaders surveyed the damage they knew the marina would be rebuilt, but they wanted a survivable marina to replace it. They turned to City engineers and asked, “What do we need to do?” The responsibility fell on the shoulders of Ed Seissiger, project coordinator in the City’s engineering department. It was a challenge that would require imagination and persistence. What followed was a ten-year campaign of engineering, permitting and project financing that Seissiger relentlessly championed. The exposed outer marina This article describes the construction of the outer marina and its floating docks, wave attenuators and barrier islands. The inner marina is cut into the shoreline and is sheltered. It was also damaged, but its fixed docks were soon repaired to keep the marina in business. The outer marina is exposed to a long fetch from the southeast. As the hurricanes proved, the location needed a dramatic engineering solution. Seissiger and his team considered their options. “We wanted to do something beyond typical shoreline hardening,” Seissiger said. “We looked at breakwater walls and even a giant jetty projecting out from the shore. But the most intriguing solution was to create one or more man-made islands. Islands and lagoons create excellent habitat for birds, dune vegetation and provide artificial reefs for juvenile fish and shellfish.” The City hired the engineering firm Tetra Tech of Stuart, Florida, to develop engineering studies. In 2005, Tetra Tech presented eleven designs with cost-benefit analyses. Funding and Permitting The Federal Emergency Management Agency (FEMA) offered to supplement the .5 million the City had from insurance proceeds to rebuild the marina but insisted that City find a way to protect its investment. They warned Ft. Pierce that if the new marina was destroyed in a storm they would not get another loan. Bids for replacing the marina came in at million and island construction at .5 million. With permitting, engineering and materials acquisition, the project cost million. Seissiger and team met with the state and federal elected officials and persuaded them to back the barrier island solution. In 2007 the Florida Department of Environmental Protection, The new exposed outer marina with concrete docks (as below left), are sheltered by a barrier island solution. the Florida Governor and Board of Trustees (entrusted with oversight over state land) also approved the plan. The Army Corps of Engineers would not begin their approval process until the state had finished theirs, so the process essentially had to start over adding two years to the project. The Corps gave their approval in 2009. Engineering studies Engineers studied weather, topography and other factors to estimate the worst wind and wave the new marina would have to withstand. Seissiger involved three different engineering firms through peer reviews. “Their estimates for the highest design wave came within onetenth of an inch of each other,” he said. The rules had changed. When the previous marina was built, Florida allowed operators to order boats out of the harbour before a hurricane. After Hurricane Andrew in 1992, marina operators could no longer tell tenants to leave. Docks and pilings would have to withstand the sail-area pressure of more than 100 boats bearing on the structure. They decided to engineer the new marina to survive Category 3 hurricanes with boats in the marina and Category 4 storms without. Testing the island design FEMA provided a grant to build a 1/40 scale model in laboratory conditions. “The test was done at Queens University in Kingston, Canada,” - September/October 2015 39 MW2015SepOct.indd 39 05/09/2015 14:12:25

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