VI. A. 1. Types of Structures |
Shoreline stabilization structures are designed to alter physical processes by modifying hydraulic forces and controlling sediment movement and supply. A wide variety of shoreline stabilization structures have been designed to dissipate wave energy, maintain navigation channels, control shoreline erosion, repair storm damage, protect from flooding, and store or accumulate sediment (Cox et al. 1994). Shoreline stabilization may be established through the use of “hard” and/or “soft” structures. “Hard” solutions, or armoring, typically involve the addition and arrangement of materials that would not naturally occur at the site (Macdonald et al. 1994). Hard structures include bulkheads, seawalls, revetments, groins, and breakwaters (Canning and Shipman 1995a; Williams and Thom 2001) (Figure VI-1). “Soft” solutions are dynamic approaches to preventing or reducing erosion using naturally occurring materials (Cox et al. 1994). They include the placement of beach material (sediment “nourishment”), large woody debris (i.e., beach logs), drainage control, and shoreline vegetation (Canning and Shipman 1995a; Macdonald and Witek 1994; Macdonald et al. 1994) (Figure VI-2).
Figure VI-1 Illustrations of hard approaches to shoreline stabilization. Top: vertical smooth bulkhead (Applied Environmental Services, Inc.); Middle: revetment; and Bottom: groins (© WA Dept of Ecology 2000/2001)
Figure VI-2 Illustrations of soft approaches to shoreline stabilization. Top: nourishment with gravel and sand; Middle: large woody debris; and Bottom: vegetation (from Zelo and Shipman, 2000).
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