Linking water quality and beach morphodynamics in a heavily impacted tidal creek in Myrtle Beach, South Carolina

Event Location: 
BCCMWS Room 100
Event Date: 
Thursday, September 4, 2014 - 3:00pm
Event Type: 
SCMSS Seminar Series

Presenter: Brittany Hoffnagle

Tidal creeks, locally known as swashes, are important transition zones which facilitate water exchange from the land to the ocean. Morphological changes to tidal creeks can have ecological implications for the natural dynamics of the ecosystems. Singleton Swash is a tidal creek in Myrtle Beach, South Carolina that is representative of a highly modified tidal creek that experiences morphological change due to coastal processes (e.g., longshore current, wave intensity, weather events). The dynamic nature of this swash results in erosional risks to adjacent resort properties and a decline in water quality within the tidal creek. This study aims to monitor the morphological change of Singleton Swash and its’ effect on water quality by coupling the use of highly accurate GPS technology and a suite of water quality parameters. Monthly topographic maps were created and subtracted to identify areas of erosion and deposition using ArcGIS. Over a six month period, a natural sill developed causing a deflection of the swash mouth to the south direction consistent with the prevailing direction of long shore current. This diversion to the south resulted in a dampening of the tidal prism amplitude indicating that the mouth was beginning to close. Future post- processing will include a variety of Arc GIS tools to make correlations between a suite of metrics (e.g., sinuosity, angle of across-shore orientation, radius of curvature) and water level. This extensive unique data set will represent the pre-condition state before a more permanent structure is constructed at Singleton Swash.