Hard Armoring

Description

Hard armoring has been the traditional approach to shoreline protection. This includes the construction of bulkheads, seawalls, revetments, dikes, tide-gates, & groins, among others. Areas with considerable development & critical infrastructure may require hard armoring.

Hard armoring can protect valuable development & critical infrastructure from coastal flooding & erosion. These practices can allow for continued use of a developed area, even as sea levels rise. However, armored shorelines have a number of potential drawbacks to consider. As such, localities should carefully consider where to implement hard armoring.

Case Study

In its 2015 Floodplain Management and Repetitive Loss Plan Update, Portsmouth summarizes its work in identifying & funding improvement projects. The City repaired tide gates that had maintenance issues & is preparing a cost estimate for the construction of additional floodgates.

Case Study

Louisiana designates Levee Districts to maintain and operate the state’s flood and hurricane protection systems, including levees, floodwalls, pump stations, and floodgates.  These districts are typically funded through property & revenue taxes.

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Funding

FEMA HMA Grants: Non-localized Risk Reductions Projects are eligible for the Hazard Mitigation Grant Program & Pre-Disaster Mitigation funding, including the construction or modification of dikes, levees, floodwalls, seawalls, groins, jetties & breakwaters.

Virginia Shoreline Resiliency Fund: The VSRF was created to act as a revolving loan program for shoreline protection. Although currently unfunded, the program may one day be a useful tool in living shoreline implementation.

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Many shoreline armoring projects adopt a hybrid approach, creating living shorelines protected by offshore breakwaters as shown here along the York River. For other examples, view the VIM's SAGE mapper displaying completed projects.

Locality Feedback

Over 80% of Virginia’s shoreline is privately owned. Property owners have a tendency to prefer traditional hard armoring solutions, as they are well understood & neighboring properties often have existing riprap & bulkheads.

Benefits

• Can provide a high degree of protection to valuable infrastructure & development
• Popular support among property owners
• Can protect large areas, making them especially useful for urban areas

Drawbacks

• Expensive to construct, maintain & repair
• Armoring does not always prevent or mitigate erosion, waves overtopping seawalls and bulkheads during storm surge events can erode landward of the structure. In addition, armoring can shift and intensity erosion downstream to unprotected shorelines. 
• Can create a false sense of security (failure of a seawall or levee = potentially catastrophic consequences)
• May encourage further development along the coast
• Limits the upland migration of wetlands
• Virginia does not require removal of structures inundated by SLR

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Guidance

Construction that has the potential for encroachment on or damaging primary sand dunes or beaches is not permitted without review and approval by the VMRC and a local Wetland Board. A Joint Permit Application is required for the majority of development projects within tidal waters, wetlands, & coastal primary sand dunes/ beaches within Virginia. While living shorelines are technically the preferred method of shoreline management within the Commonwealth, in practice many localities approve projects using traditional hard armored structures. A stringent permitting process can prohibit implementation in instances where natural infrastructure would be more effective.

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CRS Credit

1. Up to 1,000 points (Activity 530, Flood Protection, Manual pg. 530-6)

Credit for small-scale flood control projects that protect insurable buildings. Projects must protect against at least the 25-year flood

2. Up to 1,600 points (Activity 530, Flood Protection: Retrofitted Buildings, Manual pg. 530-2)

Credit for installation of individual property barriers, including levees, berms, & floodwalls that protect insurable buildings located in the floodplain. Barriers must protect against at least the 25-year flood

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Legislation

Va. Code § 10.1-658:

The General Assembly supports & encourages measures which prevent & mitigate effects of storm surges and flooding

Va. Code § 15.2-970:

Localities may construct a dam, levee, seawall or other structure to prevent tidal erosion, flooding, or inundation

Va. Code § 28.2-1100:

VIMS shall engage in research and provide training & technical assistance to Board of Conservation and Recreation on erosion along tidal shorelines

Clean Water Act, Section 404, River and Harbors Act Sec. 10:

Grants ACOE authority for essentially all ground-disturbing activities in navigable waters & adjacent wetlands

Tools
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Resources

Adams, S., Crowley, M., Forinash, C., & McKay, H. (2016). Regional Governance for Climate Action . Institute for Sustainable Communities.

City of Hampton. (2014). City of Hampton Tidal Floodplain Study and Protection Plan.

Grannis, J. (2011). Adaptation Tool Kit: Sea-Level Rise and Coastal Land Use. Georgetown Climate Center.

Mitchell, M., Hershner, C., Herman, J., Schatt, D., & Eggington , E. (2013). Recurrent Flooding Study For Tidewater Virginia . Virginia Institute of Marine Science.

Titus, J.G., D.E. Hudgens, C.Hershner, J.M. Kassakian, P.R. Penumalli , M. Berman, and W.H. Nuckols. 2010. “Virginia”. In James G. Titus and Daniel Hudgens (editors). The Likelihood of Shore Protection along the Atlantic Coast of the United States. Volume 1: Mid-Atlantic. Report to the U.S. Environmental Protection Agency. Washington, D.C.