Editor’s note: Beginning in July 2013 this blog has posted a series of stories on the environmental monitoring of the Savannah River as part of the Savannah Harbor Expansion Project (SHEP). The monitoring program continues and some will be expanded and continued into the future. This article encapsulates the information presented in this blog over the past 18 months.
Environmental stewardship remains a top focus of the Savannah Harbor Expansion Project. Deepening the Savannah harbor will impact the ecosystem of the estuary and conditions in the river all the way to the base of the Thurmond Dam north of Augusta, Georgia.
As explained in the initial post, the Corps of Engineers and the State of Georgia must deepen the Savannah harbor and shipping channel to accommodate much larger ships, many of which will soon be able to pass through the Panama Canal. The SHEP will deepen the harbor and shipping channel from its current 42 feet below mean low water to 47 feet.
We opened this blog series with a discussion of the overall importance of environmental monitoring. The story outlines the robust monitoring program for the SHEP. It explained how eight of the 14 monitoring studies start before construction begins.
“Some of the pre-construction environmental monitoring takes a year or longer to accomplish before we can begin any work,” Jason O’Kane, senior project manager for the SHEP with the U.S. Army Corps of Engineers Savannah District, said.
“Monitoring will provide the public assurance that the Corps protects the environment and local drinking water,” William Bailey, chief of the Planning Division for the District, said.
We explained how the Corps of Engineers partners with state natural resource agencies to monitor the endangered shortnose sturgeon and Atlantic sturgeon. We explained why and how we plan to offset the impacts on the sturgeon. Harbor deepening would allow additional saltwater to enter the harbor and travel further upstream into areas currently used by endangered sturgeon species. The increased salinity may reduce the suitability of some of these areas for young sturgeon. To compensate for this expected change, the SHEP includes construction of a large fish bypass around the first dam up the Savannah River, the New Savannah Bluff Lock and Dam.
“The data collected from the SC DNR studies will establish a baseline for measuring potential impacts of the harbor deepening on sturgeon,” Corps biologist Mary Richards said. “The data will also help us measure the effectiveness of the fish bypass once it is built, and will be useful if we need to take any corrective actions as part of adaptive management.” Corrective actions would come in the form of adjustments to the fish bypass.
Besides sturgeon, the SHEP also impacts other animals and many plant species. Through the Corps’ partnership with Clemson University, scientists collect valuable data on the Savannah River estuary as part of the preconstruction monitoring program. In April 2014, Clemson researchers completed the installation of 12 monitoring stations in the estuary. The stations cover the full range of marsh types: freshwater, brackish and salt marsh.
“Each monitoring station collects data for water elevation, above ground salinity and below ground salinity on an hourly basis,” said Jamie Duberstein, Clemson research assistant professor with 14 years of experience monitoring the Savannah River. The data collected by Clemson University will establish a baseline for SHEP pre-construction conditions, allowing the Corps to measure changes in salinity and vegetation during and after harbor deepening.
Because the Savannah River’s water quality impacts sturgeon, other aquatic animals, plants, and humans, the Corps conducted intensive water quality monitoring in the harbor and estuary in 2014.
“The data we collected gives us a comprehensive snapshot of the current existing conditions of the Savannah River and the estuary,” said Bryan Robinson, a hydraulic engineer for the Corps’ Savannah District. “The data will give us a good baseline – a good tool – to measure our mitigation efforts as the harbor is deepened.”
In the $1.1 million research effort, the Corps’ Savannah District gathered data from sensing devices placed temporarily in the river and estuary, according to Robinson. They also collected data from existing gauges permanently in use by the U.S. Geological Survey.
The Department of Interior, which oversees the USGS, was one of the four cabinet-level agencies which developed and approved the deepening project. (The Department of the Army, the Department of Commerce and the Environmental Protection Agency were the others.) Partnering with the USGS gave the Corps access to a sophisticated network of continuous monitoring stations.
“After years of field studies by a diverse group of federal, state, and local stakeholders, we worked with the Corps to develop a comprehensive monitoring network to ensure the SHEP functions as intended,” said Brian McCallum, assistant director with the USGS Georgia Water Science Center.
Besides the estuary, the SHEP could, under certain conditions, impact portions of Savannah’s water supply. By deepening the Savannah River to the Garden City terminal, slightly elevated levels of salinity may extend further upstream, increasing chloride concentrations in Abercorn Creek which is a vital water source for Savannah residents and local industries. The planned construction of a freshwater impoundment to store raw water solves this problem. The city’s treatment plant can use water from the impoundment on occasions when high tides and low stream flow result in higher chloride levels.
The approximately two-year construction project is scheduled to begin during the summer of 2015 and be operational before the completion of inner harbor dredging.
Meanwhile, a team of scientists from the University of Georgia are conducting one year of baseline monitoring of blood and tissue samples taken from birds in the dredge material containment areas. The tests will measure cadmium levels in bird species found at the DMCAs. Some material dredged from the river contains naturally-occurring cadmium. (See SHEP FAQ 22.) These tests, conducted before placement of dredged material with associated concentrations of the heavy-metal, will help biologists determine if the dredged material in question is having an impact on birds once the deepening begins.
Collected birds are banded for future sampling that will continue during construction and three years post-construction, said UGA ecologist Larry Bryan, who helps conduct the monitoring.
Monitoring the SHEP’s impacts on the Savannah River will continue during and well beyond completion of the deepening. We will continue our series as the project progresses.
~Billy Birdwell, Senior Public Affairs Specialist