Beach and Borrow Site Sediment Investigation for a Beach Nourishment at Ocean City, MarylandNative beach sediment and sediment from 9 potential borrow sites were investigated in 1986-87. The project, as finally completed, constructed a beach 8 miles long with a 100-ft-wide berm. A total of 2.7 million cu yd was removed from two borrow sites and placed on the beach. This report discusses the method used in sampling and analyzing sediment from the native beach and each borrow site. Beach samples were collected at periodic intervals along 36 profile lines perpendicular to the beach. Samples extended from the upper berm to -30 ft National Geodetic Vertical Datum. Grain size was computed for each sample, and a grand composite sample was computed for the entire beach. Results suggest that this technique collected and analyzed more samples than were necessary. Sampling schemes should be closely tied to local profile closure depth and take advantage of natural alongshore consistency in grain size. A streamlined sampling plan could also benefit the final calculated composite and improve the chance of nourishment success. Borrow sites were investigated through a combination of geophysical surveys and vibracores. Subbottom profile data were useful in locating potential coring sites. Channel samples were removed from each core and grain size analyses performed. Composite samples calculated for each borrow site were compared with the native beach composite to develop overfill ratios. Data from the cores, along with environmental and political considerations, reduced the number of potential borrow sites to three. (edc). |
Common terms and phrases
Analysis for Borrow approximately Army Engineer Waterways Assateague Island ASSAWOMAN BAY average barrier bathymetric beach fill beach nourishment beach nourishment project beach samples berm Birkemeier borrow material borrow site sediment calculated CERC closure depth coarse Coastal Engineering composite sample core locations data collection Delmarva determine dredging Engineer Waterways Experiment erosion Fenwick Island Figure Flank ft & Depth ft NGVD ft² geophysical data hindcast Holocene hydrographic surveys inlet interval investigated layer linear shoals Location Core Maryland maximum Mean Std Dev miles native beach nearshore negative skewness number of cores number of samples Ocean City Ocean City Inlet offshore overfill ratio percent phi phi potential borrow sites profile line profile record Sample Number Sand Mean Stand sand units seaward sediment samples shoal crest shoreline short cores side-scan sonar sieve significant wave height Skew Mud standard deviation subaerial subenvironment Summary of Vibracore Table Vibracore Analysis Vicksburg Waterways Experiment Station weight yd³ zone