The influence of the Cape Fear River on characteristics of shelf sediments in Long Bay, North Carolina

UNCW Author/Contributor (non-UNCW co-authors, if there are any, appear on document)
Michael P. Slattery (Creator)
The University of North Carolina Wilmington (UNCW )
Web Site:
Lynn Leonard

Abstract: The Cape Fear River (CFR) is a low discharge river, which drains the largest area of any rivers fully contained within North Carolina. The river is formed in the Piedmont by the convergence of the Haw and Deep Rivers and then flows southeast through the state terminating into Long Bay in the Atlantic Ocean. Long Bay is the most southern in a series of bays along the North Carolina coast. mud drapes observed in the bottom sediment deposits of Long Bay are unique in that no such deposits are found in Onslow Bay to the North. The CFR is the most reasonable source of this material, though no relationship has been shown between discharge from the river and variations in sediment composition and texture. The nature of these muds (permanent or mobile) is important as mud particles can provide a substrate by which pollutants can be transported into the coastal ocean. If these deposits, then, are stable they could serve as a sink for these pollutants while if they are mobile they may act to continually reintroduce these materials into the water column. Bi-monthly sampling of both TSS concentrations in the water column and surficial bottom sediment deposits at seven sites (site 1, site 2, site 5, site 6, site 7, site 8 and site 9), starting in the mouth of the river and moving southwest away from the river mouth, occurred from September 2003 through November 2004. Physical parameters like discharge, precipitation and wind were obtained from outside data sets collected by NOAA, the USGS, the Coastal Ocean Research and Monitoring Program, and the State Climate Office of North Carolina. Results show that when compared to the control site (site 1) located directly in the mouth of the river, mean TSS concentrations at those two sites located closest to the Cape Fear River mouth (sites 2 and 6) were significantly correlated. The organic content of bottom sediments at sites 2 and 6 was significantly and positively correlated to mud content of bottom sediments. In addition bottom sediment mud and organic content was significantly and positively correlated to three TSS concentration parameters. It would appear then that at least for those sites proximal to the river mouth a definitive relationship between the TSS concentrations and bottom sediment deposits becomes more clear. Those sites more distal from the mouth showed little if any variation in both TSS concentrations and sediment composition except in rare occasions specifically following peak discharge events related to an extratropical storms. The infrequency of the sampling made characterization of these more distal four site (site 5, site 7, site 8, and site 9) difficult, though with an increased frequency it may become possible to define the nature of variability seen at these locations. Site 7 especially would be expected to be defined as a site impacted by the river derived materials.

Additional Information

A Thesis Submitted to the University of North Carolina at Wilmington in Partial Fulfillment of the Requirement for the Degree of Masters of Science
Language: English
Date: 2009
Cape Fear River Basin (N.C.), Marine sediments--North Carolina--Long Bay, Sedimentation and deposition
Marine sediments -- North Carolina -- Long Bay
Cape Fear River Basin (N.C.)
Sedimentation and deposition

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