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Water-Related News

Port Tampa Bay proposes giant recycling project

As giant cranes are building a new eight-lane span of the Howard Frankland bridge in Old Tampa Bay, an artificial island just east of the bridge in Hillsborough Bay is known globally as a significant bird nesting site.

Called 2D, it was originally built between 1978 and 1982 as a spoil island to store the soil and sand dredged from the bay bottom to create the shipping channel that accommodates the nearly 5,800 ships that traverse Tampa Bay every year. Surrounded by 29-foot containment dikes with a bowl-shaped interior where dredged materials can be pumped and stored, 2D is home to thousands of nesting birds including oystercatchers that are state-listed as a threatened species.

But like many of the coastal lands in Tampa Bay, ship wakes are severely eroding the western shoreline that’s adjacent to the shipping channel. Over the course of a year, these ship wakes generate roughly 100,000 joules per meter of cumulative wake energy, which is equivalent to the energy of a compact car traveling at 67 miles per hour slamming onto the shore. This destructive wave energy is washing away some of the critical habitats that beach-nesting birds depend upon, which is where the Howard Frankland construction comes in.

Once the new span is finished late next year, the original span – built in 1959 – will be demolished, leaving an estimated four million tons of concrete that will need to be disposed of. Port Tampa Bay has proposed barging 150-foot sections to build a series of breakwaters 500 feet off 2D that will minimize those damaging wakes on the island, creating calmer waters for seagrasses and a wider beach for nesting birds.