Lake Waccamaw and the Carolina Bays

by Amanda Rossillo | The News Reporter | September 2021

The first two installments of Backyard Science focused on two fascinating local plants--the Venus flytrap and longleaf pine--both of which can be found here in Southeastern NC. In the next two installments, we'll turn to the wondrous wildlife of Lake Waccamaw, starting with its unique ecological features that make it a suitable home to rare plants and animals.

Lake Waccamaw is one of hundreds of Carolina Bay Lakes, which span the East coast but are concentrated in the Carolinas. There were once hundreds of thousands of these lakes across this landscape, but most have been filled in or drained and are now used for farming. The origin of these lakes have puzzled scientists for nearly a century: almost all of them are oriented northwest to southeast, are small and shallow, contain acidic water, have flat bottoms, and are ringed with a buildup of sand around the rim. Many are also dependent on rainfall, and dry up in the summer.

There are many theories about when and how these lakes developed, but not a single agreed upon answer. Some scientists believe that the ocean that once covered the region left pools of water behind, and strong winds from the northeast shaped those pools into what we see today. Others say that the bays were created by meteorite showers that left depressions in the landscape, which were eventually filled in with water. This is the belief of the Waccamaw Siouan Tribe, whose oral history describes the formation of Lake Waccamaw.

Lake Waccamaw is unique among the Carolina Bays for several reasons. It is the largest of them by far, covering nearly 9,000 acres, while the majority are just 500 feet long. It also has its own water source: Big Creek and the surrounding swamplands fill the lake year round. Like other Carolina Bays, the water in Lake Waccamaw is dark as a result of acids that are released from decomposing vegetation. These acids, called tannins, are also important components of tea, coffee, and wine. However, many plants and animals cannot survive in the acidic water usually found in the bays--if the water is too acidic, most fish eggs will not be able to hatch. Lake Waccamaw is unique in that water from the swamp flows through a limestone bluff before reaching the lake, which neutralizes the acid and allows a diversity of life to thrive.

Because of these characteristics, Lake Waccamaw is home to some animals that are not found anywhere else on Earth. These endemic species include fish like the Waccamaw silverside and mollusks like the Waccamaw spike mussel and the Waccamaw siltsnail. Lake Waccamaw's shores are also home to rare plants like the green-fly orchid and longleaf pine. 

Lake Waccamaw isn’t just known for its rare living species—in 2008, a nearly three million year old whale skull was discovered by Columbus County resident Cathy Neilson. This spectacular find of a Balaenula whale—an extinct group related to humpback whales—is one of only a few that have ever been recovered.

Carolina Bays are important features of the landscape. Along with providing habitats for rare species, these wetlands also purify water and store the excess produced by storms, reducing the damage caused by flooding. Lake Waccamaw is also a source of recreation and is culturally and historically significant to the Waccamaw Siouan Tribe.

Many Carolina Bays were once seen as a nuisance, and have been filled in or drained to be used for farming or development. Lake Waccamaw is one of the few protected Carolina Bays in the country. Visit Lake Waccamaw State Park to learn more about what makes this lake so special. Come see our exhibit on the endemic species of Lake Waccamaw at the Museum, too.