Northern Prairie Wildlife Research Center
Hopkins, South Carolina
Congaree Swamp National Monument created in 1976, is preserved as a unique area for several reasons. The 22,200 acre tract is one of the best remaining examples of a mature forested southern floodplain. Over 320 plant, 41 mammal, 24 reptile, 52 fish and 175 bird species have been identified in the Monument. In 1979 the forest contained six national and 19 state record trees. Sixty-four trees were found to be within 80% of being record trees.
Where complete, the forest canopy is high and thickly woven, giving the illusion of twilight during summer days.
In 1989, Hurricane Hugo passed through the area leaving areas of altered micro-environments. Within the Monument many mature trees were twisted and broken or uprooted, leaving extensive holes in the forest canopy. The forest is in the process of growth from the hurricane impact.
Geologically, the Monument is located in the Congaree River floodplain between the Upper Coastal Plain and Middle Coastal Plain subprovinces of South Carolina. The Congaree River floodplain is bounded on the northeast by several succeeding terraces of the Middle Coastal Plain and on the southwest by the Orangeburg scarp of the Upper Coastal Plain. The Upper Coastal Plain contains upper Cretaceous sediments, the Middle Coastal Plain is Quaternary in age and the river floodplain itself is recent alluvial sediment. The terraces to the northeast contain examples of Carolina Bays which can be distinguished on the topographic map. As you drive into the Monument area you may notice these areas as forested places surrounded by fields.
The floodplain of the Congaree River is much wider than the river itself. Meandering by the Congaree River has produced several oxbow lakes, remnants of the rivers that have been cut off due to erosion accompanying the process of meandering. Wise and Weston Lakes are excellent examples of this type of feature.
Much of the Congaree Swamp is dry most of the year. The area becomes "swampy" when the Congaree River floods, spilling out of its channel and inundating the entire floodplain. The Monument is flooded, on average, 10 times a year, providing the forest floor with nutrient-rich sediments. February is the most frequently flooded time. Flooding generally occurs 16 to 22 hours after rain. Flooding may also occur after releases of water out of Lake Murray. The drainage basin for the Congaree extends north to Western North Carolina by way of the Broad River so that the melting of heavy snows impacts the volume of the river.