Waccamaw River


Source and Flow

The Waccamaw River watershed is one of the watersheds of the Lower Pee Dee Basin that we call the greater Winyah Bay watershed because its ultimate discharge point is at the Winyah Bay estuary near Georgetown, SC.

The Waccamaw has its headwaters in the Lake Waccamaw area of North Carolina. Several extensive wetlands around the lake, most notably the Green Swamp, contribute water to streams flowing into the river. It joins with the Atlantic Intracoastal Waterway near Bucksport. As the river flows closer to the ocean, it forms the long mass of coastal land, known as the Waccamaw Neck, from the town of Murrells Inlet to the Winyah Bay. The Pee Dee River joins the Waccamaw just before it empties into the Winyah Bay. The river extends more than 140 miles from its headwaters to the ocean, draining an area of 1,640 square miles of coastal plain within two states.


The Waccamaw River is tidally influenced for about 40 miles upstream from the Winyah Bay. It is considered a blackwater river because of its dark coloration caused by pigments, such as tannins, that have leached out of vegetation growing in the extensive wetlands adjoining the river. Like other blackwater rivers, it is naturally acidic (low pH) and low in dissolved oxygen (DO). 


The River is home to a collection of diverse and rare floraPileated on the Waccamaw: Steve Berkowitz and fauna. Most notably, the American Black Bear. Several plants on the South Carolina list of rare, threatened or endangered species are found here including annuals such as Fimbristylis perpusilla (dwarf fimbry), Hemicarpha micrantha (common hemicarpha) and Echinodorus tenellus var. parvulus (little burhead) as well as perennials like the Sabatia kennedyana (Plymouth gentian) and Coreopsis rosea (pink tickseed). In savanna-like areas, including the Green Swamp and around the edges of Carolina Bays, there are also many species of carnivorous plants (e.g., Venus flytrap, sundews and pitcher plants).

People and the River

The Waccamaw River has played a major role in the history of the region through which it flows, and continues to play a role in the lives of many North and South Carolinians. It supports recreational fishing and other water sports, provides drinking water, is a venue for tourism and camping, and enhances the lives of those who touch it through its beauty and serenity. The AIWW, which gets its water from the Waccamaw and Little Pee Dee Rivers, provides drinking water for Myrtle Beach and parts of Horry County. The City of Conway, originally established as “Kingston-on-the-Waccamaw” in 1735, claims the river as a major part of its history due to its early dependence on river commerce.




Existing threats to the health of the river, and the humans and wildlife dependent on it, include pollution from point sources (e.g., wastewater treatment plants), pollution from non-point sources (e.g., stormwater runoff containing oil, fertilizers, pesticides and animal wastes) and runoff of sediment due to soil erosion resulting from development.


The area is experiencing tremendous population growth along with the resulting infrastructure development. The loss of surrounding wetlands and their natural ability to remove pollutants thus become exacerbated. Years of timber management techniques, such as ditching and draining, have also seriously diminished the sponge-like abilities of our swamps and wetlands to hold and slowly release rain and floodwaters. This rapid release of water causes more drastic swings in the river’s flow and makes the river more prone to periods of flooding and to very low flow.

Mercury and Bacteria Contamination

Both states have issued a fish-consumption advisory for the Waccamaw after the detection of high levels of mercury in several fish species. The source of the mercury is unclear; some percentage may occur naturally and some may be deposited from the air as a result of fossil fuel burning. During periods of low water flow or as a result of polluted runoff during major rain events, some portions of the river are unsuitable for swimming due to high levels of fecal coliform bacteria.

Research Data

Various agencies are involved in research associated with water quality on the Waccamaw. For example, South Carolina Department of Health and Environmental Control, U.S. Geological Survey and Dr. Susan Libes of Coastal Carolina University have documented the following indicators over several years of study. More studies are needed for additional data for definitive conclusions.

  • Increased turbidity, nutrients, and pesticides following rainfall events;
  • Increased biochemical oxygen demand from non-point source runoff in a river that has naturally low assimilative capacity for oxygen-demanding organic material and acids;
  • High mercury in fish likely due to atmospheric deposition but its migration into fish is likely the consequence of the low dissolved oxygen and low pH of the natural waters;
  • High bacterial contamination that may be chronic but is increased by polluted runoff;
  • USGS has documented large fluctuations in water flow which are natural but which may be aggravated by human activities such as ditching and draining of wetlands.



Several significant conservation efforts have succeeded in designating and / or preserving important lands along the Waccamaw. The Waccamaw National Wildlife Refuge, centered around Sandy Island in Georgetown County, was established in 1998 “to protect diverse habitat components within a unique and threatened coastal river ecosystem.” The South Carolina Heritage Trust Program has preserved land along the Waccamaw corridor in the area just below the North Carolina border. Lake Waccamaw has been designated as “Outstanding Resource Waters” and the North Carolina Nature Conservancy protects a portion of the Green Swamp along with other conservation lands purchased by the North Carolina Coastal Land Trust.

If this important watershed is to be protected, citizen activists must become involved!

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