Following criticism that discussions on whether to deepen JaxPort underestimated environmental problems, engineers suggested deepening the St. Johns River would help the environment in the long run.
Deepening the St. Johns River from the Dames Point Bridge to Mayport would allow larger ships to come into the port, and larger ships means fewer trips to carry the same amount of cargo. That would cut down on the amount of carbon emissions coming from the ships, said Col. Alan Dodd, district engineer for the Army Corps of Engineers, at a City Hall forum Tuesday afternoon.
River advocates say current studies underestimate impacts to seagrass, ignore the impacts on river quality during droughts, water withdrawals, and damage from waste disposal and runoff into the river.
Representatives from JaxPort and the Army Corps said the project is environmentally responsible and won’t do more harm than the river would experience naturally.
But engineers and river advocates agree that it’s difficult to know for sure what will happen to the environment if the river is dredged.
DANGER OF SALT WATER
A deeper harbor could mean fewer ships, but that could also mean more emissions from trucks that carry out the cargo. There is also no guarantee that large ships will mean a reduction in the number entering the port.
Deepening the river would increase the amount of salt water in the St. Johns, but how harmful is that salt water? The Army Corps says not much. River advocates say too much.
Dodd said salt water will get into the river, but that’s mainly going to be due to inevitable sea level rise. He maintains the deepening project itself won’t add very much salt water to the river.
The Army Corps of Engineers estimates that about 180 acres of underwater grasslands and 395 acres of wetlands will have to deal with more salt water. The Corps said it doesn’t think any of these plants will die from the salt water.
If seagrass and grasslands die, that saps the river of natural filters, which keeps it healthy during times when waste is dumped. Without seagrass and grasslands in the river, said Lisa Rinaman, the St. Johns Riverkeeper, who is one of the primary advocates for water issues in Northeast Florida, the waterway is vulnerable to toxic algae blooms. Last year, she had to tell residents to stay away from the river during a particularly toxic algae outbreak.
“To me, it’s not honestly looking at the bigger picture,” said Rinaman.
The Corps will also buy 638 acres to turn into conservation land, Dodd said. Right now, the agency is considering areas near the St. Johns River Blueway or near the Timucaun Ecological and Historical Preserve.
Meredith Rutland: (904) 359-4161