Mitigating Shore Erosion along Sheltered Coasts (2007)Ocean Studies Board
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Sheltered coastal areas, such as those along bays and estuaries, experience land loss from erosion and sea level rise much like ocean beaches. Owners of property along sheltered coasts often reinforce their shoreline with bulkheads and other structures to prevent erosion; however, this construction alters the coastal ecosystem, causing changes that threaten landscapes, public access, recreational opportunities, natural habitats, and fish populations. At the request of the U.S. Environmental Protection Agency, the U.S. Army Corps of Engineers, and the Cooperative Institute for Coastal and Estuarine Environmental Technology, this report examines the impacts of shoreline management on sheltered coasts and calls for a regional management approach that considers the environmental impacts that could accumulate if hard structures are permitted on a site by site basis. In addition, this report recommends changing the current permitting system to remove the default preference for bulkheads and similar structures and to allow more flexibility to encourage use of more ecologically beneficial erosion-control methods, such as planting of marshes.
- Implementation of a regional plan will require a new commitment for coordination among local, state, and federal programs, including a regional general permit.
- Although loss of small parcels of shoreline habitat from hardening may not have a large impact on the ecosystem, the cumulative impact of the loss of many small parcels will at some point alter the properties, composition, and values of the ecosystem. In addition, the economic, recreational, and aesthetic properties of the shoreline will be altered, with potential loss of public use, access, and scenic values.
- Cumulative effects of shoreline hardening projects are rarely assessed and hence are generally unknown. However, an appreciation of the potential cumulative effects will be necessary to prevent an underestimation of the impacts of individual projects.
- Currently there is no national mandate to document erosion processes on sheltered coasts or to develop regional scale plans. No federal agency has been assigned to provide that scale of planning, although some states have become more proactive in shoreline management.
- In most areas, the scope and accessibility of information regarding the causes of erosion at specific sites and the overall patterns of erosion, accretion, and inundation in the broader region (estuary, lagoon, littoral cell) is insufficient to support the development of an integrated plan for managing shore erosion.
- Many decision-makers, particularly homeowners but also some state and federal regulators, are not sufficiently informed about the mitigation options available to them or the short and long term impacts of their choices.
- Regional plans facilitate the assessment of cumulative impacts but require credible monitoring of project performance within and without the region of interest.
- The RSM approach provides a model and framework that could be adapted to address sheltered shoreline erosion problems within a regional context.
- The current permitting system fosters a reactive response to the problem of erosion on sheltered coasts. Decision-making is usually parcel-by parcel and based on little or no physical or ecological information.
- The current regulatory framework for sheltered coasts contains disincentives to the development and implementation of erosion control measures that preserve more of the natural features of shorelines, mainly as a result of the combined lack of knowledge, vision, and planning.