Edisto River Basin Wetlands

Scott Jones, Scott Smith, Erin Allen, Jue Jiang

Figure 1. Sunset view of the Edisto River estuary in South Carolina (SCDNR, 2006).


Spring 2009

Wetland Environments   *    Emporia State University

Introduction
Hydrology
Soils
Wildlife and Vegetation
Edisto River Basin Project
Future of the Basin
References


Introduction

The Edisto River Basin and its associated wetlands are located entirely within the state of South Carolina. The basin is made up of the areas located around the north and south forks of the Edisto River and the areas downstream of where the two forks merge (Figure 4). Included in the basin are 30 watersheds and approximately two million acres of land of which approximately 45% is forested land, 29% is agricultural land, 15% is forested wetland, 5% is barren, 3% is water, 2% is nonforested wetland, and 1% is urban land (SCDHEC, 2004). The river basin begins in the Sandhills, flows through the Upper and Lower Coastal Plain Regions, and runs onto the Coastal Zone region where it eventually meets with the Atlantic Ocean. The river itself is the longest completely undammed or unleveed blackwater river in North America (NRCS, 2008). Some tributaries of the Edisto River are dammed but the main river channel remains undammed. Many tributaries are dammed to create farm ponds. The river meanders approximately 250 miles through the coastal plains of South Carolina.

ACE (Ashepoo-Combahee-Edisto) Basin is South Carolina's most undeveloped basin which contains diverse habitats such as saltwater and brackish-water marshes, maritime forests, upland, pines, and bottomland hardwoods. The first appearance of human activity in the Basin occurred approximately 6,000 years ago with the Paleoindians. The lower coastal plain of South Carolina, including the Edisto River basin has been affected by repeated cycles of sea level rise and fall which is characterized by sea islands, marsh islands, and barrier islands. These islands are all interconnected by estuaries, salt marshes, intertidal areas, and oyster reefs. The Edisto River has the largest watershed of the (ACE) rivers. The Edisto is the primary source of sediment which has been eroded from upland areas (SCDNR, 2009).

Figure 2- South Carolina watersheds (SCDHEC).
Figure 3- ACE (Ashepoo-Combahee-Edisto) Basin watersehds (ACE 2).
Figure 4-The Edisto River Basin (permission to use; State Research, 1997).

Return to top


Hydrology

The Edisto River Basin originates in the Sandhills region and flows through the Upper and Lower Coastal Plain Regions and into the Coastal Zone Region. The Edisto River sub-basin drains four tributaries within the ACE Basin: South Fork Edisto River, North Fork Edisto River, Edisto River, and Four Hole Swamp. The Edisto River is influenced by tide changes within approximately 21.7 km (35 mi) of the coast and the saltwater interface extends approximately 12.4 km (20 mi) inland during high tide. Stream flow in the Edisto River is measured at approximately (74 m3/sec, or 2,614 cubic feet/sec, at Givhans Farry) and is fairly constant. Surface water in the Edisto River sub-basin supplies approximately 93% of the total water demand for public supply and agricultural irrigation. Total water use in the Edisto River sub-basin is projected to increase 52% by the year 2020, with agriculture and thermoelectric power plants being the leading gross water users (ACE 2).

Figures 4 & 5-The north and south portions of the Edisto River Basin. The areas shown in red are valued at the highest level, followed by dark green, and then light green. (FRED, 2008)

Ground water in the ACE Basin is spread out between six aquifer systems from three different confining units in the lower coastal plain. The main aquifer systems are Cape Fear, Middendorf, Black Creek, Tertiary Sand, Floridan, and Shallow. Only three of those aquifers are in use today. The Tertiary sand and Floridan aquifer systems are the main sources of domestic, commercial, and public water supplies, and well yields as great as 1,900 L/min (500 gpm) are reported across most of the basin. The shallow aquifer system contributes the least amount of water with respect to well yield. Some wells drilled in areas underlain by beach facies provide enough water for domestic supply and produce up to 190 L/min (50 gpm) locally. Treatment is required for hardness in the water from the Tertiary sand and Floridan aquifer systems and for dissolved iron in water from the Floridan and Shallow systems. The Shallow aquifer produces water with low-dissolved solid concentrations except when it comes in contact with saltwater marshes and streams. Saltwater intrusion occurs in the Floridan aquifer system at Edisto Beach due to water-level declines. Chloride concentrations in the Floridan aquifer at Edisto Beach can be expected to increase with time due to pumping-induced saltwater intrusion (ACE 2).

The South Carolina Department of Health and Environmental Control has established water quality standards that must meet beneficial uses (e.g., drinking water, recreational use). The SCDHEC takes periodic measurements at many different stations in the ACE Basin. They have been sampling the water for more than 14 years. Some of the measurements obtained include; pH, conductivity, salinity, temperature, dissolved oxygen (DO), turbidity, fecal coliform bacteria, nitrogen, and phosphorus. After the SCDNR analyzed the water samples and water quality data, they concluded that the water quality within the ACE Basin met or exceeded standards. However, with increasing urbanization and development, water quality in the ACE Basin is predicted to decline unless strict management practices are applied (ACE 2).

Figure 6- Deposition facies in the shallow aquifer system. (ACE 2)

Figure 7- Surface water monitoring sites in the ACE Basin. (ACE 2)

Return to top


Soils

The soils found in wetlands generally are characterized by frequent, prolonged saturation and low oxygen content, which lead to anaerobic chemical environments where reduced iron is present (Aber, 2009). The majority of the soils found in the Edisto River Basin wetlands have those characteristics; although, there are some differences throughout the different regions of the wetlands. In the northern portion of the Lower Coastal Plain region, where there is an abundant amount of sand, the soils tend to be greatly affected by droughts and erosion. Also, the amount of soil organic matter is quite low in this region, which decreases the overall health of the soil (NRCS2, 2008). In the more southern portion of the Lower Coastal region, droughts and low soil organic matter are still the major issues due to high sand content in approximately 52% of the land area, but high levels of erosion and wetness are experienced less often (NRCS3, 2008). The soils characteristic of the Coastal Zone region are dominated by wetness and erosion is not a major concern (NRCS4, 2008).

In all the regions the majority of wet, hydric soil is found along streams in riparian areas, and the soils most susceptible to erosion are the ones on the steepest slopes. The majority of the farmland soils are not wetland soils as they tend to be deep and well-drained; these soils are mostly found in the Upper Coastal region. These soils are some of the most productive soils in South Carolina, as nearly one-fifth of the state’s annual cash receipts for timber and forest products and about one-third of the state’s cash receipts for crops and livestock (FRED, 2009).

Figure 8- Butressed trees in a wetland soil. Soil Science

Return to
top


Wildlife and Vegetation

The Edisto Basin sustains 95 natural ecological communities including aquatic communities, which in turn protect a large variety of wildlife. Because of its undeveloped wetland ecosystems, many nationally endangered or threatened species, such as wood storks, red-cockaded woodpecker, southern bald eagle, loggerhead turtle, and shortnosed sturgeon, can be found in Edito Basin. Game animals are abundant in this area, such as white-tailed deer and the eastern wild turkey.

A total of 87 freshwater species and 120 saltwater species of fish have been recorded at the basin. Fish species like striped bass and American shad have both recreational and commercial value, and redbreast sunfish, flat bullhead, and channel catfish are easily to be found in the Edisto river ("Edisto Attractions"). The Basin is mainly covered by mixed hardwood, pasture, longleaf pine, and bottomland hardwood Forest (National Audubon). Some unwelcome non-native species are also noticed in the Edisto basin, such as the common reed (Phragmites australis), which have displaced some of the endemic marsh species, and the green porcelain crab (Petrolisthes armatus), which have invaded oyster reef areas in fall and winter ("ACE Basin").

Vegetation

Figure 9- The Live Oak tree is commonly found in sandy soils on or near the coastal plain.(ACE 1)

Figure 10- The Loblolly Pine trees grow best in poorly drained soils and can reach heights of 46 meters (150 ft). (ACE 1)

Wildlife

Invertebrates

Figure 11- The Fiddler Crab inhabits the intertidal zone where it can construct burrows up to 60 cm (23 inches) deep. (ACE 1)

Figure 12- The Grass Shrimp are amoung the most common estuarine inhabitants in South Carolina. (ACE 1)

Fish

Figure 13- The Largemouth Bass is found in the riverine ecosystem and prefer slow moving water. (ACE 1)

Figure 14- The Silver Perch are common in South Carolina estuaries as well as shallow tidal creeks. (ACE 1)

Amphibians

Figure 15- The Green Tree Frog can be found in marshy swamps or on the bank of a pond. (Audubon)

Figure 16- The Southern Toad is a nocturnal toad which is commonly found in areas with sandy soil. (Audubon)

Reptiles

Figure 17- The Loggerhead Sea Turtle has been on the United States and South Carolina List of Endangered and Threatened Species since July 28, 1978. (ACE 1)

Figure 18- The American Alligator can be found in the coastal marshlands of South Carolina. The ACE Basin is one of the most important nesting areas along the east coast. (ACE 1)

Birds

Figure 19- The Red-tailed Hawks inhabit deciduous forests and open country. They are most commenly spotted during the winter months. (ACE 1)

Figure 20- The Peregrine Falcon is typically found on barrier island beaches and waterfowl impoundments in South Carolina. (ACE 1)

Mammals

Figure 21- Bobcats typically inhabit dense areas with thick brush near the costal plain. (ACE 1)

Figure 22- The Eastern Cottontail Rabbit is the most common rabbit found in the Edisto River Basin. (ACE 1)

Return to top


Edisto River Basin Project

The Edisto Basin Project was designed to evaluate and plan the Basin's ecological, cultural, and economic assets. The National Oceanic and Atmospheric Administration (NOAA) funded the water resource division of the South Carolina Department of Natural Resources, the South Carolina Department of Commerce, and the South Carolina Department of Parks, Recreation and Tourism to conduct the evaluation. These organizations were further spilt into fifteen more specialized committees, which included nearly 200 citizens of the basin. In 1996 this task force finished its collection of information that would be used to assess the situation. A multi-resource data base was created to assist in efficient and proactive decision making (FRED 2, 2009).

A geographic information system was used to analyze the data base to determine potential conflict areas between the resources. The maps that were created using the GIS can be seen at the Friends of Edisto website. The conclusion of the assessment showed the importance of the Basin's natural and cultural aspects in the community's heritage and economy. There have been 176 recommendations proposed by the task force that can be reviewed in full in the Edisto River Basin Project Report. The recommendations fall within a few major subject matters such as economic development, forestry, agriculture, tourism, wildlife, water resources, recreation, and cultural resources (SCDNR, 2006). The suggestions for sustaining the task force's goals are:

The Edisto River Basin falls within a greater land conservation project called the ACE Basin Project. The project is one of the most significant land conservation efforts in the eastern half of the United States encompassing three of South Carolina's river basins including the Ashepoo, Combahee, and Edisto Rivers covering over 350,000 acres. The ACE Basin Project started in 1988 when Ducks Unlimited, The Nature Conservancy, the South Carolina Department of Natural Resources, the U.S. Fish and Wildlife Service, and local private landowners got together to try and maintain the natural character of the region (CCA, 2009). The project has been a huge success and has grown from protecting wetlands and waterfowl habitat to protecting the rural landscape of the region.

Figure 23- ACE Basin National Wildlife Refuge is one of the largest undeveloped estuaries on the East Coast of the United States. Cranes

Return to top


Future of the Edisto River Basin

Ongoing efforts are underway for the promotion of conservation, wise management, and enhancement of the Edisto River Basin. Local organizations like the Friends of the Edisto (FRED) have been put together to help protect and enhance the natural and cultural character and resources of the Edisto River Basin through conservation and responsible use (FRED 3, 2009). One of FRED's main goals is providing accurate information for local governing bodies and landowners to assist them in their plans for land use projects. Organizations like FRED are specifically and passionately focused on the Edisto Basin are a sure way to ensure a bright future for the region.

Several state parks and conservation areas within the Edisto River Basin help protect the river and its inhabitants. These parks have been set up for the public to enjoy the plants, animals, nature, and history of the area and save them from development and ruin. The addition of the 4,630 acre Botany Bay Plantation is a great example of an area that has been set up by advocates of the basin to create an environment where they can educate a wide spectrum of people in the importance of conserving the river and its basin. An active approach is taken here by getting visitors involved through several ecotours that focus on the animals, plants, natural and cultural history of the area (BBE, 2009). With the combination of sound management practices and wetland protection, the Edisto River Basin could remain one of the United States most untouched black water rivers.

Figure 24- Interior wetland on ACE Basin Island approximately 45 miles south of Charleston, SC. NOAA Photo Library.

Return to
top


References

Aber, J. S. 2009. Wetland environments: definitions and classifications.
http://academic.emporia.edu/aberjame/wetland/define/define.htm [retrieved 29 Apr. 2009].

ACE Basin Executive Summary (ACE 1), Biological Resources Image Gallery. NOAA.http://www.dnr.sc.gov/marine/mrri/acechar/specgal/birds.htm [retrieved 7 Apr. 2009]

ACE Basin Executive Summary (ACE 2), Environmental Conditions. NOAA. http://www.dnr.sc.gov/marine/mrri/acechar/esenviro.htm [retrieved 7 Apr. 2009]

ACE Basin National Estuarine Reserve (ACE 3). Image ID: nerr0029 NOAA's Estuarine Research Reserve Collection, 2007.[retrieved 7 Apr. 2009]

ACE Basin National Estuarine Research Reserve (ACE 4), NOAA Magazine. 1 May. 2009. http://www.magazine.noaa.gov/stories/mag137.htm.

Botany Bay EcoTours (BBE). 2009. http://www.botanybayplantation.com/Home_Page.html [retrieved Apr. 2009].

Centers Francis Beidler Forest, Audubon South Carolina.[retrieved 1 May 2009]. http://www.cooperativeconservationamerica.org/viewproject.asp?pid=89 [retrieved May 2009].

Department of Soil Science, North Carolina State University. Program Areas: Wetland Soils. http://www.soil.ncsu.edu/programs/wetlands. [retrieved 7 Apr. 2009]

Friends of the Edisto, Inc. (FRED 1). 2009. Friends of the Edisto. http://www.edistofriends.org/index.htm [retrieved 30 Apr. 2009].

Friends of the Edisto, Inc. (FRED 2). 2009. Edisto Attractions. http://www.edistofriends.org/attractions.htm>.. [retrieved May 2009]

Friends of the Edisto, Inc. (FRED 3). 2009. Edisto Basin maps. http://www.edistofriends.org/edisto_basin_maps.htm [retrieved Apr. 2009].

Friends of the Edisto, Inc. (FRED 4). 2009. Mission. http://www.edistofriends.org/mission.htm [retrieved Apr. 2009].

International Crane Foundation, ICF. www.trackingcranes.org/en/acebasin_donnelley.html [retrieved 7. Apr. 2009]

National Audubon Society, 2009. http://www.esri.sc.edu/Projects/usda/conservation_documents/RWAs/Edisto.pdf [retrieved on 29 Apr. 2009].

Natural Resources Conservation Service (NRCS2). 2008. An assessment of the North Fork Edisto subbasin: hydraulic unit code 03050203. http://74.125.93.132/u/sc?q=cache:UxdHJXaF74kJ:www.esri.sc.edu/Projects/usda/conservation_documents/North%2520Fork%2520Edisto.pdf+EDISTO&cd=5&hl=en&ct=clnk&gl=us&ie=UTF-8 [retrieved 30 Apr. 2009].

Natural Resources Conservation Service (NRCS3). 2008. An assessment of the South Fork Edisto subbasin: hydraulic unit code 03050204. http://74.125.93.132/u/sc?q=cache:A7n0UfhxQlEJ:www.esri.sc.edu/Projects/usda/conservation_documents/South%2520Fork%2520Edisto.pdf+Edisto+River&cd=8&hl=en&ct=clnk&gl=us&ie=UTF-8 [retrieved 30 Apr. 2009].

Natural Resources Conservation Service (NRCS4). 2008. An assessment of the Edisto subbasin: hydraulic unit code 03050206. http://www.esri.sc.edu/Projects/usda/conservation_documents/RWAs/Edisto.pdf [retrieved 30 Apr. 2009].

South Carolina Department of Commerce (SCDC). 2009. Infrastructure: water and air. http://www.sccommerce.com/locateinsc/infrastructure/waterair.aspx [retrieved 1 May 2009].

South Carolina Department of Health and Environmental Control (SCDHEC). 2004. Watershed water quality assessment: Edisto River Basin. http://www.scdhec.gov/environment/water/docs/edisto.pdf [retrieved 29 Apr. 2009].

South Carolina Department of Natural Resources (SCDNR). 2006. Edisto River, project overview. http://www.dnr.sc.gov/water/envaff/river/wsedisto.html [retrieved Apr. 2009].

State Research: The State. 2008. ACE basin: protected forever. http://www.thestate.com/154/story/584599.html [retrieved 30 Apr. 2009].


This webpage was designed for Wetland Environments
Instructor: Dr. James S. Aber of Emporia State University
Created on May 1, 2009

Return to top