From the AJC’s Signs look hopeful 
for deepening river:
For Atlanta, the consequences are huge. Businesses across the metro region shipped $9.5 billion in cargo through the ports of Savannah and Brunswick the past fiscal year, according to the Georgia Ports Authority. More trade, and revenue, is expected once — if — Savannah’s harbor and 32-mile channel to the sea are deepened from 42 to 48 feet. Dredging is expected to take four years.
Such statements that persist in the media have no founding in the Corps of Engineers economic analysis, which I wrote about extensively here: Port cargo growth would be the same with or without dredging, according to Corps of Engineers. That post also contains a link to my column covering the issue in the Savannah Morning News.
The COE’s analysis is very simple: we’ll have fewer but larger ships come to the port if the river is dredged. But shipping companies aren’t about to mothball all their existing vessels. Without dredging, according to the COE, we’ll see the same increase in cargo, but it will come in on more ships. Under either scenario, we’ll max out the landside capacity in 2032, according to the analysis.
The economic impact will NOT be from increased trade, but from cost savings and various efficiencies (fewer ships having to wait on the tides, more flexibility with larger vessels, etc.) that will be felt broadly across the economy. Some — maybe even most — of the savings will be for multinational shipping companies.
We could throw out the Corps analysis, I suppose, but that’s the same organization whose environmental analysis we are forced to trust.
And there’s plenty of reason for the state to want to back the project, but the port’s volume and capacity will not be affected whether the port is deepened or not.