Hydrology of the Waccamaw River

Event Location: 
BCCMWS Room 131
Event Date: 
Thursday, September 25, 2014 - 3:00pm
Event Type: 
SCMSS Seminar Series

Presenter: Benjamin Thepaut

The Waccamaw River Basin (HUC 03040206), is located on the coastal plain and meanders from North Carolina to South Carolina. This tidal black-water river flows parallel to the coast past the cities of Conway and Georgetown, terminating in Winyah Bay. The river is also hydrologically connected to the Atlantic Intracoastal Waterway (AIW) with net discharge occurring during periods of high freshwater flows. The tides are semi-diurnal with an amplitude classified as meso-tidal (2-4 meters). The semi-diurnal tidal amplitude in the Waccamaw River declines with increasing distance upstream from Winyah Bay and the AIW. Temporal variations in this longitudinal gradient reflect varying effects of astronomical tides, weather, and river discharge. Streamflow data collected at a new USGS gaging station (02110550) located on the Waccamaw River at river mile 63.0, upstream of Winyah Bay has recently documented an unprecedented tidal reach.

Station 02110550, Waccamaw River above Conway, SC, became operational in June 2013, just prior to a significant flood event. When water levels receded in early September, a semidaily tidal amplitude of 0.4 to 1.0 feet was observed through the end of December 2013. Net upstream flows during flood tides were observed from September 22 to November 26, 2013. Subsequent rainfall led to increasing discharge and declining tidal amplitudes. Predictors of the tidal reach, as well as biological distribution, chemical phenomena, and physical processes that occur at the tidal reach will be examined statistically and descriptively. This information aims to benefit local scientists and highlight the importance of USGS long-term gaging stations.