Shoreline Armoring: The Pros and Cons

Millions of federal, state, and private dollars have been expended annually on shore armoring and protection, which can cost anywhere from $1,800 to $7,600 per linear foot of coast (Griggs, 2005).

The shorelines of the United States are dynamic and diverse, shaped by natural processes and human intervention. The complex physical process that results in a loss of shoreline sediment, known as coastal erosion, is also influenced by both natural factors and human activities (Figure 1). Given the importance of the coast for the nation’s economy and our quality of life, coastal states work to ensure conservation of coastal habitats and maintenance of coastal ecosystem services, both of which can be severely affected by coastal erosion. In some cases, this management effort includes shoreline armoring—adding physical structures to harden a shoreline against erosion.

Shoreline armoring has both beneficial and detrimental effects (Table 1). These effects vary by site, based on the kind of shoreline stabilization system employed, and how that system interacts with a particular site’s beach composition and environmental dynamics.

Managing a shoreline effectively requires balancing the need to protect the public from coastal hazards with the need to maintain the integrity of the natural system. At times, shoreline management may require the use of hard, stabilization techniques such as breakwaters, riprap, or groins to wall off the sea. Recently, however, more attention is being placed on alternative shoreline management techniques, including: soft, non-structural stabilization; hybrid stabilization; and new, policy and planning approaches. For more on these alternative techniques, see http://coastalmanagement.noaa.gov/initiatives/definitions.html

Sources: Griggs, 2005; NRC, 1990; Riggs, 2001; Williams and Johnston, 1995; O’Connell 2010

Figure 1                                             Table 1
Land Loss Interactions   Land Loss Interactions
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Figure Source: Modified from Morton, 1977
Table Sources: Kriesel and Friedman, 2003; O’Connell 2010

 


 

Seawall

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Concrete seawall protecting homes from direct impact of storm waves on the South Shore of Massachusetts. Credit: University of Hawaii Sea Grant Program


Revetment

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Coastal bluff with non-structural coastal armoring that prevents sand from eroding from the bank while feeding the adjacent beach and dunes. Credit: University of Hawaii Sea Grant Program