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Title: Improvements for Little River Inlet, South Carolina : hydraulic model investigation
Authors: United States. Army. Corps of Engineers. Charleston District.
Seabergh, William C.
Lane, Edgar F.
Keywords: Channel improvement
Little River Inlet
South Carolina
Fixed-bed models
Hydraulic models
Tidal inlets
Hydraulic models
Navigation channels
Tidal prism
Sediment transport
Publisher: Hydraulics Laboratory (U.S.)
Engineer Research and Development Center (U.S.)
Series/Report no.: Technical report (U.S. Army Engineer Waterways Experiment Station) ; H-77-21.
Description: Technical Report
Abstract: Little River Inlet , located near the State border of North and South Carolina, is part of the "Grand Strand," a rapidly growing resort area along South Carolina's northeast shore. The inlet is a natural channel through the coastal barrier beach that conducts tidal flows between the Atlantic Ocean, inner channels, and a lagoon approximately 6 square miles in size. The inlet also provides a restricted passage for small-craft navigation from the ocean to the Atlantic Intracoastal Waterway (AIWW) and to private and commercial docking facilities. Improvements for the inlet were authorized on 12 October 1972 and included two jetties, sand transition dikes connecting the structures to the shore, a 300-ft-wide by 12-ft-deep entrance channel through the offshore bar, and a 90-ft-wide by 10-ft-deep inner channel from the entrance channel to the AIWW. A model study was performed to aid in preconstruction planning and design of the structures and included an investigation of items such as optimum alignment, length and spacing of the jetties, current patterns and magnitudes, sediment movement patterns, effects on the tidal prism, and effects on bay salinities. The Little River Inlet fixed-bed model, constructed of concrete to scales of 1:300 horizontally and 1:60 vertically, reproduced an area extending to the -40 ft contour in the Atlantic Ocean and to the extent of the influence of the tidal prism on the AIWW. Areas throughout the lagoon were accurately reproduced and model verification tests of tidal elevations, velocities, and salinities assured that the model hydraulic regimes were in satisfactory agreement with the prototype. Model testing concluded that Plan 2D-1 which included weir sections backed by deposition basins for both jetties would be the most feasible plan. The mean tide level weirs would permit sand transport to the basins on flood tide but would prevent ebb flows from existing over them due to the tidal elevation-velocity relations characteristic of Little River Inlet where maximum ebb velocities occur after the tide elevation has fallen below midtide. Also, flow in the entrance channel was ebb-dominant which would aid in flushing sediment out of the channel. The sand-trapping abilities of the deposition basins permitted shortening of the jetties since a large amount of sand fillet storage would not be needed and sand movement around the jetty tips would be minimized. Testing also indicated there would be no significant change to the bay tidal prism or salinities. NOTE: This file is large. Allow your browser several minutes to download the file.
Rights: Approved for public release; distribution is unlimited.
Appears in Collections:Technical Report

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