Coastal Hazards

Natural Protective Features and Coastal Processes

Understanding the Dynamic Shoreline

Shorelines are inherently dynamic features, continually changing in response to natural processes and human activities. Coastal change can be sudden or more systematic and these processes support the health and renewal of ecosystems and coastal landforms. Traditionally, humans have resisted coastal change by attempting to “fix” shorelines in place and engineer “solutions”, interrupting natural sand transport processes and impeding natural coastal processes. These approaches often increase erosion in adjacent areas, place human lives and property at risk, and result in unexpected adverse impacts.

Natural Protection Features and Beneficial Functions

Natural protective features such as floodplains, wetlands, offshore bars, beaches, dunes, and bluffs help protect the shoreline by absorbing storm energy and flood waters. The presence of these features has a buffering effect for bay shorelines and low lying areas further inland. The effectiveness of natural protective features is impeded by structures and development and their cumulative effects can permanently disrupt these features, removing or weakening their protective capacity.

Developed Shoreline: Coastal Risk

Coastal hazards are created when development is exposed to risk of loss or damage by natural events.

Assessing and Managing Risk

Risk assessment is important for understanding the nature of shoreline hazard and climate change exposure. Risk will vary with topography, weather, exposure, geology, previous shore protection efforts and local conditions. Certain types of risks may be acceptable for one community and not in another.  These hazards extend across wide geographic areas and cannot be addressed on a piecemeal basis. Since the level of development and type of hazard exposure vary by locality, and the primary land use planning tools - planning, zoning, and infrastructure investment - to manage hazards risks are locally administered, local government is often the primary forum for addressing waterfront hazards. The best approach to hazard management is to develop a community plan to address potential hazards. This local focus is best supported through partnerships with federal and State programs (eg. Coastal hazard resilience plan) that provide basic standards to manage flooding and erosion hazards and a context for local management of hazard risk.

Approaches to Mitigation

Methods to mitigate coastal hazards encompass a variety of non-structural, soft-structural, and structural techniques.  Non-structural measures, including avoidance of the hazard through siting and planning considerations (e.g. implementing setbacks from natural protective features), are the preferred approach and should be the first course of action to minimize risk.  Depending on numerous local considerations and a site's characteristics, treatments such as living shorelines techniques, restoration, beach nourishment, or a combined structural approach may be appropriate.  Commercially or navigationally important areas may be treated with deference to maintenance of those uses.

Useful References, Mapping and Assessment Tools