In September 2023, we visited Congaree National Park located just southeast of Columbia, SC. Only 27,000 acres, it is dwarf-sized compared to most national parks. It is a remnant (11,000 acres) of diverse, old growth forested floodplain that was preserved through the efforts led by Henry Hampton, a local journalist, and incorporated into the national park system in 1976. It includes loblolly pine, bald cypress, sweetgum, american beech, swamp chestnut oak, american holly, water tupelo, dwarf palmetto and more. The tallest loblolly pine is 169 feet tall, and some bald cypress are nearly 500 years old. We took a ranger-led 2.4 mile hike on the boardwalk loop trail that was so informative. The guide was a retired South Carolina Department of Natural Resources biologist who knew the park well. If we had more time we'd have taken the Cedar Creek kayaking trip that would have provided a different vantage point for viewing the park.
There were once 35,000,000 acres of forested floodplain that existed in the southeast and Gulf of Mexico before white settlers began arriving here in numbers in the 1700's. Trees were cut for gain - ships, railroads and buildings, and the lands were drained and converted to pastures, farms and cities. But something was lost too. Floodplains provided natural storage for floodwaters. Floodplain guts (pictured above) are shallow swales that regularly conveyed floodwaters and nutrient rich sediments from rivers that were deposited in the forested floodplains. Oxbow lakes, like Lake Wilson (pictured above), were formerly meandering rivers that migrated downstream and, often during a flood, cut through the neck of the meander, leaving a a semicircular curved lake that provides habitat for waterfowl and fish.
The natural storage that was once provided by forested floodplains has been replaced with engineered, large-scale flood risk mitigation projects involving river channelization, levees, floodwalls and reservoirs all of which. Today's floodplain managers and water resources engineers can sometimes use the principles evident in nature within Congaree National Park's floodplains to reduce peak flows and sediment delivery to lakes and streams through projects that increase natural floodplain storage through reconnecting anthropogenically modified streams to their floodplains using channel plugs, bank lowering, floodplain plantings, and spreaders to create features similar to what the guts (also called sloughs) do naturally.
This quote by William Faulkner beautifully describes a gut.
"The thick black, slow unsigned stream almost without current,
which once each year ceased to flow at all and then reversed -
spreading, drowning the land and subsiding again, leaving it
still richer...." William Faulkner
So while much of our old growth forested floodplains have been permanently lost, this wonderous preserve illustrates naturally what floodplain managers and water resources engineers can attempt to recreate in some locations today. I am fortunate to have had the opportunity to appreciate this pristine forested floodplain and to learn by seeing the principles of how rivers and their floodplains work together in an ecologically beneficial manner.
