Multiple projects to both aid the port of Tampa Bay’s navigational safety and enhance wildlife habitats involving its two dredged material disposal islands in Hillsborough Bay were completed in September 2015.
The Florida port is home to some extremely rare birds and its large dredged material islands have proven to be magnets for many of them, resulting in autumn and winter ‘dredging windows’ so as not to disturb birds during the nesting season that runs from 1 April to 31 August.
The islands provide protected nesting habitat for American Oystercatchers and many other seabird species, hosting as many as 1,000 migratory birds.
Speaking to IHS Maritime, the port’s dredging project manager, Patrick Blair, commented, “We perform all of our maintenance dredging between September and April, but the Tampa Electric Company [TECO] needed to dredge the Big Bend Shipping Channel outside that window, during the summer.
“The work was carried out by Orion Marine Construction,” Blair continued, “with hydraulic dredging over three months that saw 76,000 cubic yards [58,000 m³] removed costing USD3.7 million. The channel’s width varies, but the work has returned it to its permitted depth of 34 ft [10.4 m].”
Because of the possible impact on rare birds, the port, TECO, and Orion Marine worked under the oversight of the Florida Fish and Wildlife Conservation Commission, the Migratory Bird Protection Implementation Committee (MBPIC), Audubon Florida, and BirdLife International.
“It was key to getting permission to immediately begin the dredging that allowed safer movement of our ships into the power plant at Big Bend,” said Kristy Apostol, TECO’s environmental health and safety engineer.
Audubon Florida sanctuary manager Mark Rachal noted, “The dredged material was piped on to the northern of the two dredge disposal islands. We surveyed the shoreline and found a section where American Oystercatchers were not nesting, which allowed Orion Marine to bring the dredge pipe onshore without impacting nesting birds.
“Oystercatchers remain one of Florida’s rarest species,” Rachal added, “with fewer than 400 pairs in the state, the nesting population on the dredge disposal islands is the largest.”
The northern island also saw the National Oceanic and Atmospheric Administration (NOAA) oversee installation of an oyster reef habitat creation project – three linear limestone rock bars stretching nearly 430 m were installed close to the island’s eastern shore to offset oyster habitat lost during an earlier acid spill.
“Immediately after the limestone oyster bars were installed, they were full of small marine animals, including thousands of tiny crabs, and birds began to forage on the bars right away,” stated NOAA’s Jeanie Jennings.
Cindy Fury, a wildlife biologist with the US Fish and Wildlife Service’s Florida/Caribbean migratory bird field office, added, “There was a lot going on this nesting season on the dredge disposal islands. Our committee reviewed the projects in advance, and because all the contractors involved followed the recommendations we developed, the projects were accomplished safely for the birds and also for people.”
A further major project, this time on the southern dredge disposal island, was carried out by the US Army Corps of Engineers (USACE) to raise dykes and promote Black-bellied Whistling Duck nesting.
“Our activities included clearing and excavating portions of the island interior,” explained USACE lead engineer Andy Cummings. “Extensive co-ordination with MBPIC and our contractor, Carter’s Contracting Services, allowed us to ensure this major construction work was carried out without endangering any birds or their chicks.”
Co-operation with environment and fauna and flora agencies is vital to smooth port operations, noted Chris Cooley, Tampa Bay’s environmental affairs director. “The dredge disposal islands are recognised as ‘globally significant’ for birds. Projects need to be successfully accomplished while nesting birds remained undisturbed, and we feel that this co-operation is key to keeping port activities on schedule.”
Port Tampa Bay president and CEO Paul Anderson added that the port authority had an integral role in the restoration, improvement, and protection of the bay’s environmental health.
“We at the port will continue to engage in meaningful long-term initiatives that sustain and improve life in these delicate habitats,” he stated.