Background. The Panama Canal was built with a maximum width. Ships have been built for a century with a planned maximum width not to exceed the safe transit width of the Panama Canal. Ships were said to be Panamax if they could fit. Over the past few years efforts have been underway to widen the Panama Canal and lock system. This means that larger ships will be able to transit the canal and that in turn means that such ships will be financed, constructed and out into service. Wider longer ships have a tendency to have deeper draft depths.
Most American ports cannot handle ships with 50 foot drafts. The biggest ships will not be able to service American ports. The search is on for Global Gateway port facilities. Two options emerge. Find a suitable port from an existing harbor or modify existing ports to accommodate the anticipated deeper draft ships.
Freeport in the Bahamas has a natural 65 foot harbor and probably could be made into an ideal offloading port for the new Panamax ships. No dredging required.
In the US the major infrastructure projects are designed and built by the US Army Corps of Engineers. USACE offices are independent entities and for example the Charleston and Savannah Offices of USACE do not consider what’s happening in adjacent districts. Advancement is based on projects garnered at one port. There is no Southeast regional body in USACE that could adjudicate project differences or even consider a regional approach. The Savannah Office need not take into account anything happening in any other districts.
The current dredge depth of the Savannah River is 42 feet. The port facilities of Savannah are a full 32 miles from the open ocean. Any plan to deepen the existing Savannah river channel would be required to excavate a 32 mile long 8 feet deep portion of sand mud and such to create a 50 foot navigable channel for the Savannah port. That’s 256 cubic miles of spoil.
Charleston port facilities are more like 7 miles from the Ocean and 5feet deeper for 7 miles is 35 cubic miles of spoil produced to create the 50 foot depth.
Either way that's a lot of material to pick up, move and dump. That's going to cover a significant ocean bottom. Searching for an optimal spoil zone is an on-going task.