The Nature Conservancy, U.S. Army Corps of Engineers Monitor Impacts of Water Management Study on the Savannah River

Scientists Document Improved Habitat Conditions for Endangered Fish Species

Atlanta—May 16, 2005—Under a partnership called the Sustainable Rivers Project, The Nature Conservancy and the U.S. Army Corps of Engineers are uncovering new scientific findings to advance the ecological restoration of the Savannah River basin, which has been impaired due to dam operations.

Meeting last week at the Phinizey Swamp Nature Park in Augusta, leading scientists and fisheries biologists from throughout Georgia and South Carolina confirmed that increased water flows resulting from two controlled floods in March are creating much needed floodplain habitat for fish, bird, and bottomland hardwood forest species in the Savannah River basin, including the federally endangered shortnose sturgeon and the state endangered robust redhorse.

The construction of dams on the Savannah River has altered the natural flow patterns, thereby altering key habitats for various fish and mussel species, as well as birds and other animals and plants that rely on the river.

"We designed the flows to mimic the natural spring flooding that would typically occur in the river basin if they dams were not in place," said Dr. Amanda Wrona, director of the Savannah River Project for The Nature Conservancy in Georgia. "So we are excited to find that these controlled floods are helping to restore floodplain habitat."

The increased flows and lockage of fish at the New Savannah Bluff Lock and Dam have also promoted the passage of fish species, including shad and striped bass, through the dam into essential spawning sites upriver in the rocky shoals. Scientists are anxious to know how shortnose sturgeon are responding to the flows.

"Although the increased flows have been beneficial for other fish species and for improving floodplain habitat, we do not know if sturgeon are able to navigate above the dam to spawn," said Doug Cook a fisheries biologist with the South Carolina Department of Natural Resources. "We intend to surgically insert small transmitters in the sturgeon to document movement in the coming year."

Cook, Wrona and other biologists are researching whether sturgeon can successfully spawn downstream if they are unable to access habitat above the dam.

Both the controlled releases, each occurring three days, were designed by scientists as part of the Corps’ Savannah River Basin Comprehensive Water Management Study, which is seeking solutions to balance all water needs of the basin. Developed with the input of leading scientists and Corps hydrologists, the flow prescription allowed for the release of 18,000 cubic feet per second (cfs) of water from the Thurmond Dam, instead of the current 4,500 cfs. Prior to the construction of the dam, the average flow was 18,000 cfs.

As nature would have it, the second controlled release in March coincided with heavy spring rains, causing the flows to exceed 22,000 cfs. According to Wrona, scientists are considering the natural increased flows this year, combined with the overall benefits to the river habitat, in planning for the next controlled release in Spring 2006.

The Nature Conservancy and the Corps will continue to monitor the long-term effects of the water releases on the habitat, as well as conduct additional controlled releases next spring.

"Under a partnership called the Sustainable Rivers Project, involving 14 dams and 10 rivers across 11 states, the Army Corps of Engineers and The Nature Conservancy are working together to improve dam management to better protect the natural splendor and health of America’s rivers, while continuing to provide services according to the projects’ purposes, such as flood control and power generation," said Col. Mark S. Held, the Corps’ District Commander in Savannah. "Our partnership – our common interest is in achieving environmental sustainability."

In the future, other dams will be added to the Sustainable Rivers Project. Initiated in the summer of 2002, this nationwide water management study is an outgrowth of collaborative work between the Corps and The Nature Conservancy to restore natural flows on the Green River in Kentucky, now a demonstration site for the Sustainable Rivers Project. For more information about the Sustainable Rivers Project, visit http://nature.org/success/dams.html.