Corps Looks at Channel Widening

When Bay Soundings last looked at the business of the bay in April 2003, the U.S. Army Corps of Engineers was embarking upon an ambitious review of channel depths and access across the bay. The original initiative looked at more than 30 alternatives, from a passing zone at Cut B to widening and deepening other channels in both Hillsborough and Pinellas counties, at costs ranging from $35 to $204 million.

The final plan will most likely call for widening Cuts A and B – the 7-mile segment that runs from the Sunshine Skyway Bridge past the junction to Port Manatee – by 100 feet. Funding on the project is estimated at $30 million with additional mitigation costs being considered.

The problem is the delay caused by fantasy-class cruise ships that are so large that no other vessel can pass in the channel. “These large vessels are now transiting up to 300 times per year,” notes Stacey Roth, the planner charged with steering the project through the Corps Jacksonville district. “We’re focused on finding an economically justified solution which can restore safe two-way traffic, allow safe meeting and passing, and relieve congestion in the bay.”

The Agency on Bay Management, the public-private partnership charged with protecting Tampa Bay, raised questions about the channel widening project in 2006 that should be addressed before plans are finalized, including:

• Effect of larger vessels and ship wake on seagrasses and shoreline habitat, including existing conditions so that future impacts could be identified
• Potential effect of large anchorage areas on sediment transport, circulation and salinity, larval transport and biological resources
• Increase in air pollution associated with increased ship traffic
• Possibility that the aquifer could be breached while digging the channel, potentially allowing groundwater to leak at a time when potable water is critical to the region
• Probability of damage to rare hard-bottom adjacent to the ship’s channel, which is likely there because of previous dredging, and plans for mitigation.

“These aren’t new questions – they’ve been raised at every step of the process,” said Suzanne Cooper, principal planner for the Tampa Bay Regional Planning Council and staff to ABM.

Environmental surveys are underway in cooperation with key environmental agencies, including preliminary plans to reduce the amount of hard-bottom impacted by widening on only one side of the channel. Additionally, initial evaluations indicate that only a small amount of the dredged material will be of the quality needed to place on Egmont Key, the historic island at the mouth of Tampa Bay which is slowly eroding away.