Document Type

Report

Department/Program

Virginia Institute of Marine Science

Publication Date

1978

Abstract

·1ow cost erosion control structures were installed at ten shoreline sites located in the lower Chesapeake Bay and on the Potomac and Rappahannock Rivers to further test the applicability of the perched beach concept under diverse littoral environments. The perched beach is achieved via installation of a low sill parallel to the shoreline. The objective of the sill is to provide a partial barrier behind which an elevated (perched) beach is accreted. When successful, ~he perched beach backshore and foreshore acts to reduce the frequency of direct wave attack against the fastland and thereby reducing the erosion rate. In this study, sills were used in conjunction with existing groins as well as alone. Some testing was performed on the use of a spur with existing groins as a device to prevent the formation of a downdrift erosion notch where the groin intersects the fastland. The sills were formed with a series of large PVC-coated nylon bags hydraulically filled with sand or with stone filled gabions. In one case compacted used auto tires were utilized as fill for a gabion. Evaluation of the response to the structures was based upon a series of surveyed beach profiles at each site and sequential photography. At each site the beach profiles were surveyed for several months prior to and following the installation of the various structures. Additional profiles were run adjacent to the treated areas. The structures were emplaced between late March and early June of 1978.

Keywords

Shore protection -- Virginia, Beach erosion -- Chesapeake Bay (Md. and Va.)

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