Watershed Assessments

Coastal Watershed Condition Assessments

PI: Merryl Alber (Dept of Marine Sciences, Univ of Georgia, Athens, GA, USA)
Support: National Park Service (U.S. Department of the Interior)
Timeframe: 2003 - 2005

Project objective:

The National Park Service is in the process of conducting a series of watershed assessments, "To determine the status of coastal park resources including water quality, habitat condition, invasive species, extractive uses, coastal development, and other issues affecting their condition, to identify knowledge gaps, and to make recommendations for further studies that address resource threats." (http://www.nature.nps.gov/water/watershed_reports/WSCondRpts.cfm)

The two Georgia parks evaluated (Cumberland Island National Seashore and Fort Pulaski National Monument) are part of a larger southeastern pilot program including parks in North and South Carolina, Florida, and Texas. Studies in Alaska and the Pacific west have also been initiated. For more information about other parks in the program, refer to the National Park Service website, http://www.nature.nps.gov/water/watershedconds.cfm

Cumberland Island National Seashore Assessment

Merryl Alber, Janice Flory, Karen Payne

Assessment of Coastal Water Resources and Watershed Conditions at Cumberland Island National Seashore, Georgia
(full document, PDF, opens in new window, >8 Mb)

Water Quality Conditions near Cumberland Island, Georgia (summary prepared for 2005 Georgia Water Resources Conference, PDF, opens in new window, 212 Kb)

Overview and findings:

Cumberland Island is a barrier island located in the Atlantic Ocean off the coast of Georgia just north of the Florida border. The east coast of the island is an almost continuous strip of beaches that face the ocean, whereas the remaining shore is a network of tidal creeks that flow through salt marshes and eventually open out into coastal water. Habitats associated with the island include marine areas (offshore water and associated bottom areas, tidal creeks, saltwater ponds) and associated structures (i.e. jetties, docks); intertidal areas (beaches, salt marshes, tide pools); upland areas (dunes, maritime forest, remnant agricultural areas); and inland ponds (both brackish and fresh water). Although Cumberland Island is considered relatively pristine in comparison to more highly developed barrier islands, both point and nonpoint sources of pollutants can be found nearby that have the potential to affect the island.

The largest potential water quality problem identified was low dissolved oxygen in Cumberland Sound, but there are also potential problems associated with nutrients and contaminants. Fecal bacteria are a potential problem in areas accessed by feral horses. In terms of population effects, potential problems exist as the result of the introduction of exotic species in the area. In addition, fish and shellfish (particularly crab) landings have decreased considerably in recent years. Habitat disruption on the island occurs from the activities of feral horses, particularly in tidal creeks and inland ponds. Erosion from boat traffic is also a potential problem in this regard. There was a lack of available information regarding water quality in the tidal creeks.

There are a number of additional and/or continuing observations that would be useful to have to better evaluate coastal water resources in the region. This includes improved access to existing data; continued monitoring of water conditions (particularly in light of impending development in the area); and selection and monitoring of sentinel organisms in different habitat types that could act as indicators of degrading water quality. In addition, it is important to clarify the hydrology in the area so that the watershed can be better-defined and the links between upstream pollutant and delivery to the area are betterestablished. In this regard, it would also be useful to determine the residence time of the different sub-water bodies (i.e. tidal creeks; Cumberland Sound) so that there is a means to quantify exposure and the potential vulnerability of different areas to water-borne pollutants.

Fort Pulaski National Monument Assessment

Merryl Alber and Caroline McFarlin
Assessment of Coastal Water Resources and Watershed Conditions at Fort Pulaski National Monument, Georgia
(full document, PDF, opens in new window, 3.5 Mb)

Coastal Watershed Condition Assessment of Fort Pulaski National Monument (summary prepared for 2007 Georgia Water Resources Conference, PDF, opens in new window, 256 Kb)

Overview and findings:

Fort Pulaski National Monument is located near the mouth of the Savannah River Estuary in Georgia. The Park is composed of a series of small islands surrounded by salty, tidally influenced river channels and creeks. The primary habitats in the Park are maritime forest, intertidal salt marsh, and the main channel of the estuary with its associated tidal creeks. This report provides information on the water quality and biological resources of the Park as well as the potential sources of pollution to the region. The study area for this report focused primarily on those parts of the three counties closest to Ft. Pulaski (Chatham, and Effingham County (GA) and Jasper County, (SC)) that fell within the lower Savannah River basin (USGS Hydrologic Unit Code 03060109), as well as the portion of Chatham County that surrounds McQueens Island, which falls primarily in HUC 03060204. Although there are no real sources of pollutants at Fort Pulaski itself, both point and nonpoint sources of pollutants can be found nearby that have the potential to affect its water resources.

Wastewater treatment plants and pulp and paper mills are the primary point sources of organic matter and nutrient loading in the lower Savannah River watershed. Numerous industries (including 20 Superfund sites) release contaminants to the groundwater, soil, or air, and there are also contaminants associated with dredge spoil sites. Non-point loading of pollutants occurs via stormwater runoff and atmospheric deposition. In addition, two major nuclear facilities and the Port of Savannah are located upstream of the Fort Pulaski study area.

There have been numerous alterations to the Savannah River that have likely affected conditions at Fort Pulaski, including deepening and widening of the channel for navigation and the operation of tide gates and upstream dams. At present, a proposal by the Georgia Ports Authority to further deepen the channel is being considered. The Savannah Harbor Expansion Project would involve deepening 35 miles of the navigation channel an additional 6 to 8 feet and widening bends at 12 locations. Concerns associated with the proposed deepening include its effects on water conditions (i.e. salinity, dissolved oxygen, water clarity, contaminant concentrations), and how those in turn might affect freshwater wetlands and aquatic resources (i.e. striped bass, shortnose sturgeon). Ongoing population growth and accompanying development in the area is also a concern, as it will likely alter the amount and quality of overland runoff.