SAVANNAH, Ga. (WSAV) – It’s called SHEP (Savannah Harbor Expansion Project.) It’s a major project to deepen the Savannah Harbor and now the U.S. Army Corps of Engineers says a major hurdle has been passed which will allow the project to move forward.
Dredging of the outer harbor (the ocean terminal ) was completed in 2018. However, dredging of the inner harbor (Savannah River) has not yet started. That’s because legal action taken some years ago by a number of plaintiffs including environmental groups prevents dredging of the inner harbor until the Corps can prove that dredging won’t hurt fish or marine life in the river.
The environmental concern is that dredging removes soil which lowers the oxygen level. The worry has been that dredging will deplete oxygen levels to the point that it will make it harder for fish and other marine life to survive. This is of special concern during warm, summer months when the oxygen levels are naturally lower.
In an effort to mitigate the environmental damage the Corps proposed, designed and erected what it calls two “Dissolved Oxygen Plants.” The plants are made up of large Speece cones which kind of swirl water around. First, there are oxygen generators on-site which capture oxygen from the air. River water is captured into the cones. Then the oxygen mixes with the cone water producing new water with more oxygen. That new and improved oxygenated water is then released back into the river.
The Corps says testing for a period of about two months at its downstream Hutchinson Island Plant showed results even better than it had anticipated.
“We were always really confident that it would work based on our models but part of the terms of the settlement agreement required us to test it and demonstrate with evidence that it works,” said Russell Wicke from the Army Corps of Engineers Savannah District. “We weren’t sure how well we’d actually be able to see the oxygen in the river but evidence documented in the report is clear and verifiable that we are seeing a clear increase of oxygen in the system during the days the system was running especially compared to when it’s not running.”
The Corps’ analysis is that testing of the first plant (Hutchinson Island) has produced what it calls “remarkable results.” A larger plant with 8 cones is being readied in Effingham County.
“The downstream plant on Hutchinson Island will produce about 12,000 pounds of oxygen a day. We need to produce 40,000 pounds to the other 28,000 pounds is going to come from the upstream plant in Effingham County,” said Wicke.
Wicke looks to the successful results of the first testing and believes there will be more of the same when the Effingham County plant goes online. “We know that the lion’s share of the oxygen is going to be coming from upstream so we were able to see such positive impacts from the smaller plant so when the larger one comes online we (think) we will see even better increases in oxygen.
Wicke says this moves the conversation back to the scheduling of the inner harbor dredging and believes it may start by the end of September.
He says while the Corps wants to protect the environment, it also wants to serve the economy. He says completion of SHEP means hundreds of millions of dollars a year in benefits. “So for every year we’re delayed, that’s money we’re not able to gain in the national economy. We could be taking more exports out of the harbor and exports are better for the national economy.”
Meanwhile, environmental groups have the right to view test results as part of the litigation settlement. And some have been critical of the investment in the Speece Cones (Dissolved Oxygen System) calling them essentially bubblers that are putting the Savannah River on life support.
Christopher DeScherer from the Southern Environmental Law Center emailed us saying it’s “critical this project performs as promised, not just for the test period of 30 or 60 days but forever.” He says it’s through that lens that his experts will analyze the data.