RESPONSE OF INTERTIDAL CREEK GEOMORPHOLOGY AFTER 20 YEARS OF CHANGE AT NORTH INLET, SOUTH CAROLINA

North Inlet is a small, ocean-dominated estuary located on the South Carolina coast that is minimally impacted by humans and protected under the North Inlet-Winyah Bay National Estuarine Research Reserve System. Among the mosaic of habitats within the estuary are numerous intertidal creeks, which link subtidal and marsh surface habitats during periods of tidal inundation. As such, these creeks serve as important biological and physical habitats within the estuary for free-swimming marine animals. Previous studies show that the geomorphology of a creek plays a role in its habitability. Therefore, it is important to understand how the geomorphology of intertidal creeks changes over time.

This study focuses on eight intertidal creeks that were mapped and measured in 1997. Approximately two decades later, we re-measured these same eight creeks using a combination of terrestrial laser scanning and drone photogrammetry. By comparing data from 1997 and 2016-2018 we were able to observe how the geomorphology of all eight creeks changed on a decadal time scale. Measurements of length from mouth, width at 1.5 meter intervals along the creek, depth, sinuosity, and percent oyster bottom are compared over the 20 year interval, as well as a 1 year interval for three of the creeks. Additionally, this study focused on how each creek’s substrate affected its rate of change. Three of the creeks had hard substrates composed of oyster shells, while the remaining five had soft substrates of mud. This project is the first to study how substrate affects geomorphological change in North Inlet.