The deeper we go 

A public meeting reviewing the proposed harbor deepening pits the economy versus the environment

It was an event nearly 13 years in the making when representatives from the Army Corps of Engineers (ACE), the Georgia Ports Authority and other partnering agencies presented nearly 3,000 pages of draft reports documenting the various impacts of the proposed harbor deepening.

The purpose of the four-hour event at the Civic Center last Wednesday was to accept comments and concerns from the public about the harbor deepening, which is pitting long term economic goals against fragile aquatic eco-systems. The comments will be compiled and added to the final report.

Several hundred people showed up - a mix of concerned citizens along with stakeholders like the Longshoremans Association, among others - and were able to view exhibits outlining the "three E's": Environment, economy and engineering.

Dozens of three ring binders were also available with portions of the dense, highly technical reports that were in the spotlight for the evening, the General Re-evaluation Report and the Tier 2 Environmental Impact Statement.

Currently, the path from the ocean to the port is dredged to a depth of 42 feet, which makes it difficult for larger ships to access the port when the tide is out. The reliance on the tide and limitations on the size of ship able to call on the Port of Savannah leads to inefficiencies that increase the cost of shipping.

The federal government has identified 47 feet as the optimal depth, according to the National Economic Development plan, which strives to balance cost with benefits.

The non-federal partners - the State of Georgia and the Ports Authority - would like to see the harbor deepened to 48 feet. The state has vowed to cover the additional costs associated with dredging the extra foot, totaling $33.4 million dollars.

The total cost of dredging the channel to 48 feet is $551.4 million, including mitigation efforts to offset the environmental damage of the deepening. Mitigation actually comprises more than one third of the total budget for the project.

According to the economic benefit analysis conducted by the federal agencies, the economic benefits of dredging to 47 feet are about $116 million per year, while the benefit of going to 48 feet is a close second at $115.7 million. The state's interest in going to the extra foot is based on rosier growth estimates for the port than the federal numbers.

Although the case for the economic reasons are clear-cut - it's estimated that cargo volume through the port could more than triple by 2032 - there are a significant number of environmental questions about the project.

Destruction of freshwater marshland, adverse impacts on habitat for the endangered shortnose sturgeon, the risks of exposing cadmium-laced soil in the riverbed (cadmium is toxic and can be absorbed by plants, animals and water), and potential risks to the City of Savannah's surface water intake system (which supplies about two-thirds of the potable water in the area) are among the concerns raised by environmental groups and stakeholders.

In total there are 20 threatened or endangered vertebrate species and three endangered plants that would be affected by the harbor expansion.

Several hundred pages of the report detail the environmental risks and potential mitigation efforts that would be incorporated into the project by the ACE to offset impacts of the project.

First and foremost is the concern that deepening the channel would allow higher concentrations of salt water to travel further up the channel.

Without mitigation, the deepening is likely to destroy more than 1,200 acres of freshwater marsh. In a best case scenario, if the modeling is correct, mitigation would reduce that loss to about 300 acres.

The increased depth and influx of salt water will further damage the dissolved oxygen levels in the river, which are already classified as impaired because of the amount of oxygen demanding substances dumped into the river, including nitrates and other pollutants.

"The studies also indicate that deteriorations of the lowest dissolved oxygen values... increase proportionately to the amount of the deepening," according to the report.

The system for mitigating the dissolved oxygen impact is a series of cones that pump tens of thousands of pounds of oxygen into the water. A demo run of two cones was conducted here in 2007 in anticipation of the issue, and was found to be reasonably effective at improving areas of the river in proximity to the pumps, but not the river as a whole.

Despite assurances that the calculation of impacts is being done with the best methodology possible, the ACE has a mixed record when it comes to mitigation efforts along the Savannah River.

In the late 1970s a sediment control system was put in place to help reduce the cost of sediment removal (about 7 million cubic yards of material are removed from the channel annually during maintenance dredging).

In a debacle now known as "Tidegate," the system was partially removed in 1990 because of "adverse environmental impacts," according to the ACE's report. The project increased salinity at the Wildlife Refuge, destroyed 4,000 acres of freshwater marsh and decimated striped bass populations.

With the current project there have been questions raised about the methodology used by the Corps of Engineers to calculate impacts of the project.

The City of Savannah, whose surface water system pulls directly from Abercorn Creek, expressed concerns with the ACE's predictive model for increases in salinity around the intake system.

If the rise in chlorides near the surface water intake is too great, it could require an eight-mile pipeline so that the city can draw water from further upstream. The pipeline would be paid for by the ACE, however, because of the timeline for constructing something of that magnitude, work on the pipeline would have to begin around the same time as the rest of the deepening work.

Regarding the construction of the pipeline, the report states, "at this time the best impact prediction model that is available indicates that a supplemental intake line is not warranted."

A final decision on the scope of the deepening is expected sometime in December 2011.

The period of public comment on the draft report is open until January 25, 2011. For more information, visit the Savannah District ACE's website: www.sas.usace.army.mil/


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