Alternative Shoreline Armoring
'We have begun to observe effects of shoreline armoring at both local and beach system scales (Dethier et al 2016). A wide range of technologies are being employed that attempt to provide some ecosystem services while still preventing coastal shoreline erosion. These methods are as diverse as the shorelines they are designed to protect. Different language is used in different settings to describe different combinations of techniques, but methods generally involve some combination of one or more of the following:
- Placement of rocks to deflect wave energy
- Placement of log structures to deflect wave energy
- Configuration of armoring to create protected beaches
- Setback of armoring to higher elevations
- Beach nourishment to change the slope or texture of a beach
- Embedding armoring in the beach for grade control
- Regrading the backshore to reduce slope and increase wave energy dissipation
- Integration of vegetation into shoreline developements
- Construction of terraces to increase intertidal surfaces
While coastal armoring alternatives may increase local ecosystem functions, as they are designed to prevent erosion of coastal sedimentparticles of clay, silt, sand, gravel, or cobble, transported by water, are called sediment. deposits, they do not affect beach sediment dynamics at the drift cell scale, except to the extent that beach nourish replaces natural recruitment of sediments.
- Finlayson 2006 describes a summary of Puget Sound beach processes
- Johannessen & MacLennen 2007 provides an overview of beach management as part of a nearshore restoration program
- The following reports provide information on initial installations of alternative shoreline armoring on residential properties in Puget Sound, and some aspects of engineering effectiveness.
- Zelo et al. 2000. Alternative Bank Protection Methods for Puget Sound Shorelines - a WDOE project to describe current practices (c. 2000) for alternative shoreline protection.
- Gerstel & Brown. 2006. Alternative Shoreline Stabilization Evaluation Project - a PSAT project to review the engineering effectiveness of projects described by Zelo.
- The Olympic Sculpture Park Restoration effort provides a very different example of alternative shoreline armoring in an urban environment integrating a sub-tidal habitat terrace, and a pocket beach into an otherwise stabilized shoreline.
- The Impacts of Shoreline Armoring effort describes observed impacts of armoring on beach structure and biota, potentially highlighting beach attributes that could be used to evaluate alternatives to traditional armoring.
- City of Seattle prepared a outreach product for Lake Washington landowners (file:Seattle 20xx green shorelines outreach.pdf) and maintains a website.
- Washington Sea Grant has developed a Green Shores for Homes program including a website with materials: http://www.govlink.org/watersheds/8/action/greenshorelines/
- System analysis in the Beach Strategies for Nearshore Restoration and Protection in Puget Sound may provide context for evaluating regulation of alternative systems.
- File:Ehinger et al 2015 DRAFT beach habitat value.pdf suggests a tool for quantifying change in beach function that could support regulatory analysis.