Charged with responsibility for improving harbors under the Rivers and Harbors Act of 1899, the U.S. Army Corps of Engineers is funded by Congress to study potential harbor improvements that will ensure that commerce has safe and adequate access to ports throughout the country.
After more than 14 years of exhaustive feasibility studies, the Savannah District United States Army Corps of Engineers (USACE) has finalized its general re-evaluation report and environmental impact statement regarding the Savannah Harbor Federal Navigation Project. The studies evaluated the engineering, environmental and economic acceptability of various alternatives for the present and future harbor conditions over a 50-year analysis period.
Alternative ports were considered.
“Our studies show that future shipping growth will require deepening Savannah and Charleston harbors, as well as creating a port in Jasper County, S.C.,” stated Col. Jeff M. Hall, commander of USACE Savannah District.
In fact, he continued, all major South Atlantic ports will need deepening or improvements to accommodate projected cargo growth from 2005 to 2050.
“No single port could accommodate all the growth in container volume expected in the region,” Hall stated.
According to the Savannah Morning News, the Port of Savannah is “the decade’s fastest growing and the fourth-largest container port in the nation.”
Last year, 8.7 percent of the U.S. containerized cargo volume and 12.5 percent of all U.S. containerized exports moved through this port.
In-Depth Study
In response to the new class of longer, wider container ships with three times the current ship capacity, the USACE recommended deepening the Savannah Harbor from its current 42 ft. (12.8 m) to 47 ft. (14 m). Because of the Port of Savannah’s seven-foot tide differential, a depth of 47 ft. is sufficient to accommodate the larger ships.
Specific improvements recommended include: channel deepening from the sea through the harbor Entrance Channel to the Garden City Terminal to an authorized depth of minus 47 ft.; channel widening to create meeting areas at Long Island and Oglethorpe Ranges; widening and deepening of the Kings Island Turning Basin; and channel widening at three bends.
When the Panama Canal expansion is completed in 2014, the maximum draft of vessels traveling to and from the East Coast will increase from 39.5 ft. (12 m) to as much as 50 ft. (15 m). Georgia Ports Authority Executive Director Curtis Foltz believes that the economy of scale these larger ships provide will make them the prevalent choice.
“This trend toward larger vessels is why state leaders strongly support the project to deepen our harbor,” Foltz stated.
After studying various depths and comparing costs of construction, environmental mitigation and annual operations against economic benefit, Hall said the USACE concluded that the 47-ft. depth reached the best balance between enhancing the national economy and mitigating for impacts to the environment.
“A deeper authorized depth poses additional risks to the environment and additional costs to mitigate for those risks,” he explained. “We believe we achieved the right balance with the chosen depth of 47 feet.”
Mitigating Environmental Impact
Because the harbor deepening will adversely impact habitat for one endangered species, the short-nose sturgeon, by allowing additional saltwater to enter the harbor and travel further upstream into areas currently used by this species, reducing the suitability of some of these areas, the USACE recommends compensating for the impact by constructing a large fish passageway around the first dam up the Savannah River: New Savannah Bluff Lock and Dam. This passage would restore access to historical spawning grounds for the short-nose sturgeon and open opening additional habitat for the endangered species. The gates at the dam will remain closed at flows less than 9,000 cu. ft. (254 cu m) per second to allow 100 percent of the river flow to pass through the off-channel rock ramp. The design was coordinated closely with NOAA Fisheries with an estimated cost of $30.2 million.
“We plan to add special devices called Speece Cones to inject oxygen into the estuary to replace what may be impacted as a result of deepening efforts,” Hall indicated.
In addition to the installation, operation and maintenance of oxygen injection systems at three locations in the lower Savannah River, he said a full-scale stocking program for young striped bass is planned — “to mitigate for loss of some spawning habitat.”
Modifications to tidal creeks in the upper harbor are also planned. These changes will re-direct the flow of saltwater to significantly reduce the impact to freshwater marsh, which was determined the highest priority wetland natural resource in the Savannah River Basin in 2003 by the Wetlands Interagency Coordination Team, which included representatives from Georgia, South Carolina, USEPA, USFWS and NOAA Fisheries. The flow re-routing plan essentially will direct more freshwater into the Back River area on the South Carolina side of the river.
The re-routing means the project will affect only 223 acres of freshwater wetland. This impact will be mitigated with the acquisition and preservation of 2,245 acres of freshwater marsh for the Savannah National Wildlife Refuge at a cost of $12.4 million. It also would reduce salinity in 740 acres of salt marsh, converting it to brackish marsh. Studies show the wetlands will retain the same functional value, thus constituting “no net loss” of wetlands.
To mitigate the impact of excavating 16 acres of tidal brackish marsh to remove Back River tide gates and deepen the Kings Island Turning Basin, 28 acres of brackish marsh will be restored on Onslow Island, formerly used as a dredged material disposal site.
“We increased some of the environmental mitigation features of the plan in close coordination with the Fish and Wildlife Service, National Marine Fisheries Service and the Environmental Protection Agency plus the City of Savannah,” Hall pointed out.
Economic Impact
The Corps of Engineers concluded that dredging the Savannah harbor to a depth of 47 ft. below mean low water will bring more than $174 million in annual economic benefits to the United States from 2015 through 2065, with a benefit-to-cost ratio increase to 5.5:1, primarily due to lowering transportation costs.
Ships are already experiencing problems with turning and maneuverability in some reaches of the inner harbor. A deeper shipping channel would allow fewer, larger ships to move the same amount of goods for less cost and with less congestion in the harbor. A deeper channel also would reduce delays in waiting for high tides. The result is a reduction in the cost of transporting commodities that represents a national economic development gain.
The project is expected to create more than 11,000 one-year jobs nationwide for each year of construction. Of these, Hall added, more than 3,700 will be bi-state jobs (Georgia and South Carolina), and approximately 2,400 will be local jobs.
The cost to expand the harbor will be shared between the federal government and the state of Georgia on a 70-30 basis. Already, the Georgia General Assembly has approved $181.1 million in bonds as part of the state’s share of construction costs, including $46.7 million Gov. Nathan Deal sought in his FY2013 budget request, according to the Savannah Morning News.
Timeline
Pre-construction could begin in late 2012 (early fiscal year 2013), pending completion of the Record of Decision in Fall 2012 and securing a partnership agreement with a non-federal sponsor. The four-year project is expected to be completed by 2016.
Initial work will focus on real estate acquisition and construction of the fish passage at the New Savannah Bluff Lock and Dam; removal of the Civil War ironclad CSS Georgia; installation of the dissolved oxygen injection system and construction of the water storage impoundment. The plan requires all mitigation to be completed before or concurrent with the completion of the channel deepening.
“Our plan for the deepening is to use the same methods used routinely in our maintenance dredging,” said Billy Birdwell, public affairs specialist and acting chief of the corporate communications office of the Savannah District USACE.
“Construction of certain mitigation features will require other standard construction equipment. Details of the construction are still being planned.”
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