LEADER 05943cam 2200637Ii 4500001 ocn957491791 003 OCoLC 005 20170411093731.0 006 m o d 007 cr unu|||||||| 008 160829s2016 ncuab obm 000 0 eng d 035 (Sirsi) o957491791 035 (OCoLC)957491791 040 ERE |beng |erda |cERE |dOCLCO |dOCLCQ |dERE |dUtOrBLW 043 n-us-nc 049 EREE 090 QH105.N8 100 1 Cornette, Christopher J., |eauthor. |?UNAUTHORIZED 245 10 Back-barrier sediment and hydrodynamic processes : |binsights from Rodanthe, NC / |cby Christopher J. Cornette. 264 1 [Greenville, N.C.] : |b[East Carolina University], |c2016. 300 82 pages : |billustrations (some color), maps 336 text |btxt |2rdacontent 337 computer |bc |2rdamedia 338 online resource |bcr |2rdacarrier 347 text file |bPDF |c2.57 MB |2rda 538 System requirements: Adobe Reader. 538 Mode of access: World Wide Web. 502 |bM.S. |cEast Carolina University |d2016. 500 Presented to the faculty of the Department of Geological Sciences. 500 Advisor: D. Reide Corbett. 500 Advisor: J. P. Walsh. 500 Title from PDF t.p. (viewed September 23, 2016). 520 3 Barrier islands are found around the world, and their geomorphic evolution is related to ocean and estuarine processes. Processes including sediment mobilization and shoreline evolution on both the ocean and estuarine side of barrier islands, control long-term evolution through many short-term (days) events (e.g., hurricanes, nor'easters). The Outer Banks of North Carolina are bounded by the Atlantic Ocean and the Albemarle and Pamlico Sound Estuarine System, the second largest estuary in the U.S. Back-barrier environments in the system are extensive with over 1500 km of estuarine shoreline in Dare County (McVerry, 2012). The back-barrier coast of Rodanthe, a small town on the Outer Banks, consists of an undulating shoreline, adjacent to a broad (~4 km) shallow shoal ([less than 2] covered with submerged aquatic vegetation (SAV). Shoreline and volumetric change rates, bathymetry, surface sediment grain properties, and hydrodynamic conditions were measured to evaluate sediment processes, SAV coverage and change over time. Understanding these back-barrier sediment processes is important for navigation, shoreline, and ecosystem management. Shoreline change rates (SCR) were evaluated using aerial photographs from five time steps (i.e., 1949, 1974, 2007, 2012, 2015). The average long-term SCR across the study region was -0.41 m y-1, but there was much variability. Data show the southern shoreline dominated by erosion and marsh loss with an increase in sediment banks and modification. Single-beam bathymetric confirmed the presence of a broad (~4 km) back-barrier shoal. Surface sediment grab samples displayed a dominance of fine sands with modest variation in grain size across the region and very low mud percent and organic content. Bathymetric change of the emergency navigational channel showed large deposition, and the timing suggests the importance of storm-related transport (e.g. Hurricanes Isabel, Ophelia, Irene). Calculated bed shear stresses based on the measured waves and currents indicate that bed shear stress during storms can exceed threshold of motion conditions (i.e., 0.18 N/m2) for the mean basin grain size (199 [micro]m). Aerial photography revealed the area was largely covered by SAV. Occurrence of SAV over 10 years showed little variation with consistent coverage. An optimal depth range of SAV (0.5-2.2 m) was determined based on bathymetric mapping. Three conclusions were derived from data: (1) Erosion and shoreline hardening are both important shoreline change process along on the back-barrier. High shoreline erosion rates and marsh shoreline loss lead to an increase in sediment banks or anthropogenically modified shorelines. (2) Critical shear stresses of motion are exceeded episodically with fresh breezes or stronger winds ([greater than] 10 m s-1), and ferry channel bathymetry suggest considerable sediment transport and deposition during high-wind events (e.g., hurricanes). The dominant back-barrier shoal sediments were clean, medium sands (i.e., low mud %, low loss on ignition). The low mud percent and low loss on ignition are likely maintained by regular wave reworking. (3) SAV in the study area has been persistent through time at water depths between 0.5-2.2 m. This depth range is consistent with other SAV studies and is attributable to water-level and light limitations. 504 Includes bibliographical references. 650 0 Barrier island ecology |zNorth Carolina |zRodanthe. |=^A989344 650 0 Erosion |zNorth Carolina |zRodanthe. |=^A20907 650 0 Shorelines |xMonitoring |zNorth Carolina |zRodanthe. |=^A868529 650 0 Sedimentation and deposition |zNorth Carolina |zRodanthe. |=^A17524 650 0 Estuaries |zNorth Carolina |zOuter Banks. |=^A69707 653 Back-barrier 653 submerged aquatic vegetation 653 SAV 653 sediment dynamics 653 sediment processes 653 sediment properties 653 hurricane 700 1 Corbett, D. Reide |q(David Reide), |d1971- |edegree supervisor. |=^A1373510 700 1 Walsh, J. P. |q(John Patrick), |d1973- |edegree supervisor. |=^A1373511 710 2 East Carolina University. |bDepartment of Geological Sciences. |=^A1066239 856 40 |zAccess via ScholarShip |uhttp://hdl.handle.net/10342/5906 949 |owjh 994 C0 |bERE 596 1 4 998 4511334