SAVANNAH, Ga. – A massive dredging effort began Dec. 1 to push through the final phase of the outer channel deepening for the Savannah Harbor Expansion Project, commonly called SHEP.
Up to five hopper dredges have been committed to the effort, each working 24-hour shifts to complete the deepening of the channel and the seven-mile seaward extension of the SHEP during the current environmental window which will close in the spring.
The Savannah District of the U.S. Army Corps of Engineers oversees the deepening effort which will take the harbor from its current 42-foot depth to 47 feet deep.
Quicker-acting hopper dredges can only be used during the winter and early spring in the Savannah harbor area due to environmental considerations. Experience shows fewer encounters with certain sea turtles and endangered sturgeon during these months.
In addition, the dredging contractor hired by the Corps of Engineers at times employs trawlers to move in front of the dredges to capture and relocate aquatic animals to a safer area away from the dredges. During the capture and release effort, specialists tag and register each relocated turtle or fish for future tracking.
“This major push by the Great Lakes Dredge and Dock Company will complete the deepening from Fort Pulaski and ending nearly 20 miles into the Atlantic Ocean to 47 feet,” Spencer Davis, project manager for the SHEP, said. “This is the first step to allow the larger, neo-Panamax container ships to enter the harbor with fewer tidal restrictions.”
Later, as the Corps completes more environmental mitigation and testing, they will deepen the inner harbor from Fort Pulaski to the Garden City port to 47 feet. Corps officials estimate the inner harbor deepening will be complete in 2022.
Using up to four hopper dredges for the deepening and one hopper dredge for routine maintenance in such a busy channel requires close coordination among the vessels.
“Crew safety and avoiding shipping disruption remain our highest priorities,” Jason O’Kane, navigation manager for the Savannah District, said. “The SHEP contractor Great Lakes Dredge and Dock Company and the maintenance contractor Manson Construction Company have extensive experience using multiple dredges in one location.”
The SHEP involves significant environmental mitigation features, with many nearing completion.
These include a dissolved oxygen injection system that will supply oxygen to the harbor in hotter months, a raw water storage impoundment that will provide an additional freshwater source to the City of Savannah, and a flow re-routing of the Savannah River adjacent to the Savannah National Wildlife Refuge.
Removal and relocation of the Civil War ironclad the CSS Georgia and raising containment area dikes, wrapped up in the summer of 2017, marked the first portions of the SHEP completed.
Removal of tide gates and restoring the width of the Back River between Hutchinson Island and the South Carolina banks of the river will finish this calendar year.
Completion of the dissolved oxygen injection system and the raw water storage impoundment will follow in the first half of 2018.
“The unprecedented environmental mitigation program for this harbor deepening demonstrates the commitment the Corps of Engineers has for the ecology of this region,” Erik Blechinger, deputy district engineer for programs and project management, said. “We committed to this from the beginning.”
The SHEP is projected to bring $282 million in net benefits each year to the nation, mostly in transportation cost savings. The nation will see $7.30 of benefits for every $1 spent on construction, according to the Corps’ latest economic analysis.
The outer harbor deepening remains on-budget and on-schedule, Davis said. “Barring unforeseeable delays, this final hopper-dredging phase will get this contract completed right on time,” he predicted.
~ Billy Birdwell, Corporate Communications Office