PortandTerminal.com, February 25, 2019
SAVANNAH, Ga. – The Army Corps of Engineers has finished the first of two large oxygen-injection stations on the Savannah river in Georgia. The machines are the agency’s $100 million solution to help fish breathe along a 27-mile (43-kilometre) stretch linking the Port of Savannah to the Atlantic Ocean. Otherwise, the waterway is expected to lose oxygen toward the bottom as it’s deepened by 5 feet (1.5 metres) to make room for larger cargo ships.
If the machines fail to boost oxygen levels in the river sufficiently, it could jam up the whole $973 million harbor expansion project with dredging only halfway done. That’s because a 2013 court settlement between the Army Corps, conservation groups and state officials in neighboring South Carolina hinges on proof that the injectors work as promised.
The machines are intended to compensate for a small expected drop in dissolved oxygen near the river bottom that’s home to blue crabs, striped bass and endangered shortnose sturgeon.
Rivers naturally take in oxygen from the air, and their flows help mix it down below the surface. But as the water gets deeper, it’s harder to push oxygen to the bottom. That’s especially true in the Savannah harbor, where the land is flat and motion is slowed by pushback from the ocean tides. Decades of dredging along the river have further stressed oxygen levels.
The problem gets worse in the hot summer months, when dissolved oxygen in the river has been known to drop below minimum standards set by Georgia and South Carolina. The river forms the border between the two states.
The Army Corps plans to run the oxygen injectors indefinitely, from roughly June through September each year. The agency estimates it will cost $3 million per year, said Spencer Davis, the agency’s project manager for the harbour expansion.
Conservation groups have questioned whether machines will truly offset the oxygen loss inflicted by further dredging. Chris DeScherer, an attorney for the Southern Environmental Law Center, has compared them to placing the river on a respirator.
The law centre initially sued the Army Corps in federal court, arguing the deepening project would cause irreparable damage. A settlement reached in 2013 included additional environmental mitigation by the Corps. It also requires extensive tests to show the oxygen injectors work before dredging can start on the half of the project furthest upriver toward the port.
If the machines fall short, any party to the lawsuit would be able to scrap the settlement and return to court.
Savannah has the nation’s fourth-busiest port for containerized cargo: goods from consumer electronics to frozen chickens shipped in large metal boxes. Last year, the port for the first time handled imports and exports totaling more than 4 million container units.
Copyright © 2019 PortandTerminal.com. All rights reserved. This material may not be published, broadcast, written or redistributed.