Coastal Program Guidance
Nature of the Resource
Shorelines within the National Park System include rocky shores, reefs, tidal pools, sandy beaches exposed to heavy surf, quiet bays, estuaries, lagoons, and lakeshores.
The physical dynamics that characterize shoreline environments are responsible for the large biodiversity and biological production that exist in these environments. For example, continuous wave action, delta migration, and tidal movement create multiple resource niches for specifically adapted or opportunistic species. Catastrophic natural disturbances, such as hurricanes, tsunami and landslides, also drive these systems and are an important component of a functioning ecosystem.
General Management and Protection Principles
(1) Maintain Natural Physical Processes to the Maximum Extent Possible.
As a general rule, the NPS should endeavor to manage its shoreline resources in accordance with natural shoreline processes in order to maintain the integrity of the biological and physical systems. Disruption of these physical processes directly impacts the species that depend upon them, usually resulting in diminished biodiversity.
For example, the construction of hard structures such as jetties, seawalls, and piers on shorelines interferes with longshore sediment transport and beach formation, which, in turn, interferes with habitat creation and maintenance. Activities such as dredging and filling, the nourishment of beaches, and beach scraping will at best offer temporary solutions and may lead to other unexpected, undesired, and often expensive consequences.
(2) Proactively Prevent or Reduce Impacts to NPS Shorelines from External Sources.
The construction of jetties or groins outside of park boundaries may erode park beaches. Even remote disturbances such as clearcutting, upland erosion, and urban storm drainage may discharge sediment into streams and riparian areas inside park areas and have a profound impact on park shorelines.
In some cases, the impacts of external land activities on park resources are significant enough to warrant active intervention by park managers, such as periodic beach replenishment. However, the best approach to prevent or reduce impacts on park resources from external sources is for park managers to participate actively in regional shoreline management planning groups.
Identifying and establishing solid working relationships with shoreline interest groups is critical to NPS shoreline management. The first logical step is to develop a directory of all interested parties. This directory should include names, titles, addresses, telephone numbers, E-mail addresses, and areas of responsibility and interest. The directory could prove to be extremely valuable when seeking common ground or support for issues or programs.
(3) Acknowledge the complexity of the interaction between the biological and physical environments at the land-water interface.
Given that the shoreline environment is highly dynamic and not yet fully understood, parks should gather the best possible scientific information for protecting shoreline resources. Parks should actively support and coordinate research by government and academic scientists so that park staffs are able to make reasoned and informed management decisions. An understanding of the landforms and processes will help develop a model of what may be expected to live in a particular environment, and may provide the basis for modeling if lack of funds and staff preclude inventorying and monitoring of an entire coastal segment. Further guidance about conducting research in shoreline parks is presented below.
(4) Understand the scope of activities that potentially affect NPS shoreline resources.
Shoreline issues occur on a variety of levels, from point sources to local, regional, or even global levels. For example, sediment depletion from development projects is a local issue; pollution washing up on beaches, fisheries depletion, coastal subsidence, and delta starvation are regional issues; and sea level rise is a global issue. Understanding these levels of impacts allows managers to raise the appropriate issues in the appropriate venues, at local and regional planning meetings or commissions.
Specific Shoreline Environments and Guidance
National Park System shoreline resources include a variety of geologic environments with specific management concerns, listed below.
Beach profile
A beach profile is essentially a cross-section of the slope of the beach. The profile of a particular beach changes seasonally as well as in response to storms and other natural processes. Park managers should avoid altering the natural seasonal beach profile so that both longshore (parallel to the shoreline) sediment transport and on- or offshore transport (perpendicular to the shoreline) continue unimpeded. Interference with sediment transport can result in problems such as increased shore erosion rates, reduction in beach width, and shoaling of boating channels.
Beach dunes
Beach dunes are important in creating a physical barrier between the beach and the backbarrier areas. Because the backbarrier areas are protected from storm waves and winds, they provide sheltered habitat, including breeding areas, for coastal species. Beach dunes should be managed to promote natural dune accretion and movement. Where beach dunes are relatively stable and covered with native vegetation, park managers should protect native dune vegetation from disturbance by restricting access and creating boardwalks between the beach and backbarrier (landward) areas. If the dune vegetation is disturbed, dune migration can accelerate, causing "blow-outs" or gaps in the dune.
In settings where beach dunes are naturally unstable, the introduction and colonization of the dunes by invasive nonnative plant species should be avoided. Stabilization of such dunes can change entire beach ecosystems, adversely affecting threatened or endangered species.
Bluffs
Bluffs protect headlands and uplands from the erosion of beach waves. Bluffs naturally erode as wave action undercuts the base of the bluff, causing slumping and slope failure. This erosion can be severely accelerated if the bluff vegetation or soil is disturbed. Managers should ensure that visitors do not climb up or down the bluffs, that the vegetation at the top of the bluff is undisturbed, and that structures are not built close to the edge of actively retreating headlands.
Estuaries and back bays
Estuaries and back bay areas, located at the mouth of a watershed, are considered to be some of the most biologically productive systems on earth. These areas serve as breeding and rearing grounds for numerous species, including many commercially important fish stocks, waterfowl, and shorebirds. However, estuaries also face severe threats. They are affected by physical processes such as sediment influx, erosion, and changes in sea level, and are subject to damage from coastal development. Estuaries are also affected by land uses in the watershed such as timber harvesting, agriculture, urban development, and roads, which alter the quality and quantity of water, sediments, and vegetation introduced to the estuary. They are subject to all the sediments and pollutants that drain into the surface waters in the watershed. Park managers should interact with other watershed users to identify, quantify, and minimize the amount of surface pollutants (including sediment) entering estuary areas. Managers should also be involved in coastal development planning to ensure that impacts to NPS estuaries from external development are minimized and mitigated.
An interdisciplinary and proactive approach to planning and management is a critical component of any project that manipulates a shoreline ecosystem. Planning in advance of a proposed project will allow park managers and staff to conduct appropriate studies and make scientifically sound decisions to avoid or minimize impacts to coastal resources and, if necessary, determine appropriate mitigation or restoration measures. These studies are also necessary to develop the baseline data that the park will use for monitoring during and after the project's completion.
Past and current land use practices have a profound effect on the resources and processes operating in shoreline parks. Deficits in the natural sediment supply arising from attempts to stabilize or enhance external geomorphic features using structures such as seawalls, jetties, groins, dams, as well as dredging for navigation, lead to shoreline retreat and loss of dunes and upland habitat. Filling of wetlands and lowlands for development eradicates natural features and processes.
Parks should minimize, as much as possible, the effects of park operations and projects on shoreline ecosystems. The NPS Organic Act prohibits the NPS from implementing or continuing activities that impact NPS shoreline resources and values so much that those resources and values are actually impaired. Parks may need to mitigate or compensate elsewhere for unavoidable disturbances to wetlands and to threatened and endangered species.
Past human-caused disturbances may need to be corrected through restoration. However, restoration should be approached with caution. Shoreline systems are highly complex and the science of restoring these systems is still being developed. One of the most difficult aspects of shoreline process studies involves distinguishing naturally-evolving physical processes from the effects of human-induced disturbances, and understanding how natural and human-caused disturbances interact to structure a dynamic shoreline. In order to avoid "restoring" a shoreline to an unnatural condition or having unrealistic biotic expectations, parks should compile a resource management team composed of shoreline geomorphologists, shoreline ecologists, archeologists, and managers before embarking on a restoration effort. Team members should include staff from the park, the system support office, central offices, local and state agencies, and other federal agencies and academic institutions.
Restoration projects should be related to park goals and objectives and should be included in the park's strategic plan and in any impact analysis. Restoration projects can stand alone or can serve as mitigation for a shoreline development project. Parks need to collect appropriate baseline data before restoration is initiated in order to develop a restoration model and a monitoring program. Data should also be collected to evaluate the success of the restoration project and determine timeframes for recovery. Efforts undertaken to achieve resource protection of shorelines should be identified in both the park's strategic plan and annual performance plans under resource protection goals.
Research, Inventory, and Monitoring
Shoreline studies should begin with a literature search, an inventory of the basic geologic resources and processes, an identification of gaps in available data, and a plan for further research and monitoring. The inventory should include historical positions of shorelines, dunes, and marshlands; identification of sediment transport directions and rates; wave and tidal regimes; local sea level changes; and cultural sites. An efficient monitoring program will objectively measure the trend and variability of changes in the status of these components.
Standard protocols for inventorying and monitoring have been developed for coastal areas, including coastal parks. Park staff and managers should determine if existing protocols for inventorying, monitoring, and research activities are appropriate for their park. Adopting existing protocols allows for comparison to other parks and other areas. The protocols developed for one park may not necessarily be applicable to others, although they should be useful to other parks with similar coastal geomorphology or shoreline habitat.
Shoreline interpretation programs should present the public with accurate information about changes in the shoreline through time, with a focus on the causes of change and implications to both natural resources and human occupation inside and outside the park. Interpretation of resource management programs and objectives can also foster better public understanding, support, and compliance.
Shoreline processes can pose hazards to structures and people. Potential natural hazards include storms, large waves from distant storms, rapid longshore currents, tsunamis, and erosion. Human-caused hazards include pollutants transported along shorelines, shipwrecks, and debris.
The NPS policy for addressing public safety issues is stated in Section 8.2.5 of the NPS Management Policies. This section states that decisions about whether and how to reduce risks to public safety are left to the discretion of individual park managers, who must work within the limits of funding and staffing, and who must ensure that any effort to protect public safety does not result in the impairment of park natural processes.