The facts about the proposed fish passage at the New Savannah Bluff Lock and Dam

By Tracy Robillard, Public Affairs Specialist

We received questions from upper basin stakeholders about the planned fish passage at the New Savannah Bluff Lock and Dam as part of the Savannah Harbor Expansion Project (SHEP). We’ve also heard there is some misinformation circulating in basin communities about impacts the fish passage would have on minimum outflows from the dams. Here are a few key questions and answers to provide the facts:

1)Will the fish passage increase outflows from the Thurmond Dam to meet downstream requirements?

No. The design calls for a fish passage that would use the existing minimum outflows from the Thurmond Dam according to the Savannah District Water Control Manual. Even during drought conditions, we will continue to release the minimum outflows at the Thurmond Dam without influence from the fish passage.

2)Will the fish passage reduce the pool at the New Savannah Bluff Lock and Dam?

The passage is being designed so that the pool will stay within its current operating range of 112.5 feet above mean sea level (ft-msl) to 115.5 ft-msl. Lately, we’ve been targeting an elevation of 114 ft-msl at the New Savannah Bluff Lock and Dam. When the fish passage is constructed, the pool will fluctuate more than it currently does, simulating a more natural condition while remaining within the current operating range. For example, with a river flow of 3,100 cubic feet per second (cfs), the pool would be 113 ft-msl, and all of the flow will pass through the fish passage. With river flows of 30,000 cfs, the pool would be 115.5 ft-msl, with 8,000 cfs passing through the fish passage and the remainder passing through the spillway gates of the dam.

This is an artist's rendering of the fish passage at the New Savannah Bluff Lock and Dam, shown here at 65 percent design completion. Image courtesy of Blair Remy Architects.

This is an artist’s rendering of the fish passage at the New Savannah Bluff Lock and Dam, shown here at 65 percent design completion. Image courtesy of Blair Remy Architects.

3)Why is a fish passage part of the Savannah Harbor deepening?

Deepening the Savannah Harbor would allow additional saltwater to enter the harbor and travel further upstream into areas currently used by endangered Shortnose and Atlantic sturgeon. The increased salinity would reduce the suitability of some of these areas. To compensate for those impacts, the Corps proposed the fish passage to address a highly-recognized limitation in sturgeon habitats in the Savannah River Basin. The SHEP includes construction of a large fish passage around the first dam up the Savannah River, the New Savannah Bluff Lock and Dam, located about 180 miles upstream of Savannah. The design will enable sturgeon and other species to swim past the dam and restore access to historical sturgeon spawning grounds at the Augusta Shoals. This is an important environmental mitigation feature associated with the harbor deepening.

4)How will the fish passage work?

The fish passage will essentially divert the river around the South Carolina side of the lock and dam. The design is considered an off-channel rock ramp and would look like a collection of boulders in the river making river rapids. Water will flow constantly through the rock ramp. Here’s the basic operational concept: The five gates at the dam will remain closed if inflows are less than 8,000 cfs. This would allow 100 percent of the river flow to pass through the off-channel rock ramp. When the river flows above 8,000 cfs, the gates can be opened to pass water downstream through the dam as needed. We will monitor the passage for five years after construction to ensure it performs as intended.

5)How will the fish passage impact the amount of water diverted to the Augusta Shoals?

The fish passage will not affect the amount of water passing over the Augusta Shoals. The City of Augusta diverts water into the Augusta Canal (away from the Augusta Shoals). The federal and state natural resource agencies have been in discussions with the city for several years about diverting more water into the shoals. Those parties have agreed to various flow scenarios as part of the hydropower operating license the city would receive from the Federal Energy Regulatory Commission (FERC). The Corps does not have any regulatory authority over the city concerning those flows.

6)How will the fish passage impact other dams located upstream?

Once the Corps completes the fish passage at the New Savannah Bluff Lock and Dam, it will trigger the construction of two additional fish passages upstream at the Augusta Canal Diversion Dam and the Stevens Creek Dam. However, these two additional fish passages are not associated with the harbor deepening and they are not Corps projects. The two additional fish passages are affiliated with licensing agreements between the hydropower project owners and the Federal Energy Regulatory Commission (FERC).

The City of Augusta would construct a fish passage at the Augusta Diversion Dam as part of its FERC license for the Augusta Canal. However, FERC has not yet issued the license, so this fish passage is not yet a legal requirement. This fish passage would provide access upstream to the Stevens Creek Dam, which is located about one mile north of the Augusta Diversion Dam and about 13 miles south of the Thurmond Dam near Modoc, S.C.

South Carolina Electric and Gas (SCE&G), the company that operates the Stevens Creek Dam, has a similar arrangement as the City of Augusta. The FERC license for the Stevens Creek Dam includes a provision that commits SCE&G to construct and operate a fish passage at that site, if a fish passage is implemented at the Augusta Diversion Dam. If migrating fish can get to the Stevens Creek Dam, SCE&G are required to pass them further upstream to access habitats all the way up to the foot of the Thurmond Dam. SCE&G’s commitment to FERC has been in place for several years but will not activate until fish passage is constructed at the Augusta Diversion Dam.

7)Who approved the fish passage?

We studied SHEP extensively for 13 years and published our findings in an Environmental Impact Statement. All the plans for SHEP, including the fish passage, were approved by four federal agencies: the Environmental Protection Agency, the National Oceanic and Atmospheric Administration (NOAA) National Marine Fisheries Service, the U.S. Fish and Wildlife Service, and the U.S. Army.

The other natural resource agencies extensively reviewed our mitigation plans, and we made some adjustments using their feedback. For example, the fish passage was originally planned to be a much smaller horseshoe-shaped design; but with feedback from the agencies, we adjusted it to a larger off-channel rock ramp. NOAA Fisheries issued a Biological Opinion supporting our final plan.

The Georgia and South Carolina Departments of Natural Resources and the S.C. Department of Health and Environmental Control were involved throughout the process. Additionally, the public had several opportunities to comment on the project with routine stakeholder evaluation group meetings and public comment periods.

We awarded the design contract to Blair Remy Architects in the fall of 2012. As of this writing, the design is 65 percent complete. We are coordinating the design with both the federal and state natural resource agencies.

8)Who will pay for the fish passage?

The fish passage will be funded on a cost-shared basis by the federal government and the state of Georgia. The passage has an estimated cost of $30.2 million.


If you have additional questions about the fish passage or SHEP, please visit our SHEP web page or post your questions in the comments section below.


About U.S. Army Corps of Engineers Savannah District

The U.S. Army Corps of Engineers Savannah District oversees a multimillion dollar military construction program at 11 Army and Air Force installations in Georgia and North Carolina. We also manage water resources across the Coastal Georgia region, including maintenance dredging of the Savannah and Brunswick harbors; operation of three hydroelectric dams and reservoirs along the upper Savannah River; and administration of an extensive stream and wetland permitting and mitigation program within the state of Georgia. Follow us on Twitter @SavannahCorps and on
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