The Application of Protection and Restoration Technology in Marine Habitat Management
Whether a particular marine habitat protection or restoration project should be undertaken depends heavily on whether there is reasonable probability that the desired habitat can be successfully established and maintained. Many projects have been completed; some achieved stated objectives, others have not. Each has site-specific features and responses, and experience sometimes suggests broader application. Descriptions and case studies are available, and the body of literature about specific technologies is growing (Appendix C). These materials are an essential resource for learning about technology and project performance. Coastal engineering projects that did not adequately address marine habitat in planning, design, and construction are also a valuable resource. Individually or collectively, projects offer opportunities for the adaptation and use of protection and restoration technologies in other settings.
The site-specific case studies summarized in Appendix B are representative of the best and the worst of several hundred marine habitat management projects for which documentation is available. Their successes and failures relate to planning and implementation and to potential applications of technology. Site-specific case studies include:
habitat assessments using species life histories (including shrimp habitat loss from port development in Tampa Bay);
waterway development impacts in the Savannah River, Georgia estuary;
Chesapeake Bay protection and restoration initiatives;
Tampa Bay wetland restorations;
San Francisco Bay wetland restorations;
environmentally sensitive development of Kiawah Island, South Carolina;
Seabrook Island, South Carolina inlet engineering;
marsh restoration and creation using dredged materials;
creation of waterbird nesting islands in North Carolina; and
underwater feeder and stable berms.
Additionally, three case studies examine specific technologies:
artificial reef technology and applications;
bioengineering applications for coastal restoration in the United States and Germany; and
GIS applications in marine habitat management.
Locations of the cases studied are shown in Figure 4-1.
CASE STUDY FINDINGS
Setting clear, reasonable goals in the planning stages is critical to project performance.
Project performance hinges on effective goal setting because the goals are the primary basis for planning and design. Thus, managers must decide at the outset on a project's end product. Among the factors to be considered in the goal-setting process are:
factors specific to the region, habitat, and species involved;
possible institutional constraints, such as funding and regulatory limitations;
project specific performance criteria as a basis for gauging success; and
a time frame for evaluating project performance.
When project managers clearly defined how a certain measure or structure will serve the project site, there was a basis for determining whether and to what degree project objectives were satisfied. Although a project may achieve its goals and objectives, benefits to the natural environment depend heavily on how well ecological considerations were incorporated in goal setting and design.
The Dauphin Island, Alabama, national demonstration project for underwater
berms illustrates the use of traditional coastal engineering technology in shoreline protection and habitat restoration. The project protects not only areas of both commercial and residential interest through attenuation of wave energy and erosion but coastal habitat as well. Project proponents foresaw positive impacts on marine habitat because the berms would replace deep water habitat with habitat that is essentially an artificial reef. During project coordination, U.S. Army Corps of Engineers (USACE) project managers determined that the underwater feeder and stable berms would complement beach nourishment measures rather than replace them in shore stabilization efforts. Performance could then be compared with what could be reasonable using traditional shore stabilization measures. Because of uncertainty about effects on the marine habitat, standby measures for relocating dredged material to traditional disposal sites were included. A long-term monitoring program was established to provide data for assessing project performance. Data and analysis indicate that the berms are performing as designed for shore stabilization and also as effective fisheries habitat, particularly the stable berm (Clarke and Pullen, 1992). Careful planning in this case contributed to a successful demonstration project; it has served as a model for similar shoreline protection efforts in New York, North Carolina, Texas, and California.
A multidisciplinary approach to project planning and implementation, involving a stable, multidisciplinary team, increases the chances for success.
Marine habitat protection and enhancement planning and implementation necessarily require the expertise of both coastal scientists and engineers. Multidisciplinary studies ensure that all elements of coastal processes and functions are taken into account. The key to the Kiawah Island, South Carolina, development project's success was an independent multidisciplinary professional team that performed a comprehensive environmental assessment of the area (Mark Permar, personal communication, December 4, 1992). The development corporation's engineering team met frequently with the independent assessment group to exchange information and concerns. Their reflections were incorporated in design and construction. Project objectives for development and habitat management are being met. Because practitioners cite the lack of communication between engineers and scientists and a lack of knowledge of basic ecosystem processes as barriers to beneficial applications of technology, the multidisciplinary approach at Kiawah Island is a useful model for future projects. Pointe Mouillee, Michigan, Miller Sands, Oregon, and several other projects that incorporated multidisciplinary teamwork for planning, implementation, monitoring, and open communication with the affected publics have achieved and continue to achieve performance objectives. It is noteworthy that restoration underway in coastal Louisiana pursuant to the Coastal Wetlands Planning, Protection and Restoration Act (P.L. 101-646) involves an interagency task force for planning and developing
restoration projects. In contrast, the U.S. Army Corps of Engineers' Savannah River estuary project did not achieve design objectives; technology was applied without adequately taking ecosystem and hydraulic processes into account. Waterway improvement objectives were not achieved and fisheries habitat was severely impacted (design flaws have since been corrected, although not before adverse impacts occurred in the ecosystem). These projects are detailed in Appendix B.
A long-term management strategy involving preproject, concurrent, and postproject monitoring can provide valuable information from both successful and unsuccessful projects that can be incorporated into planning and design of subsequent projects.
For valuable insight on performance of design relative to field conditions, a comprehensive monitoring regime is required. Well-planned preproject, concurrent, and postproject monitoring allows a team of coastal scientists and engineers to learn from past successes and failures. At Windmill Point, Virginia, primary project objectives for the first marsh creation project designed by the Army Corps of Engineers were not met. A temporary protective sand dike serving as a breakwater in an area that was often exposed to high wave energy eroded before the marsh had stabilized. Although most of the marsh washed out, two remnant islands and a protected shallow water habitat remained and proved useful as fish and wildlife habitat. These conditions were ascertained through extensive monitoring of the project area for more than 20 years, from planning through evaluation. The important information gained was incorporated into the planning and design of subsequent projects. Other projects that demonstrate the value of long-term monitoring include the Dauphin Island's underwater berms in Alabama, Salt Pond Three restoration in San Francisco Bay, and Miller Sands marsh in Oregon (see Appendix B).
Pilot projects with rigorous performance monitoring regimes are one effective way to study the application and effectiveness of engineering technologies and to promote future project success (NRC, 1990c).
Pilot projects with rigorous monitoring regimes are important to the success of future projects. A pilot study on the construction of offshore underwater stable berms off Norfolk, Virginia, preceded the Dauphin Island national demonstration project. The study involved berm construction and a long-term monitoring program to determine project performance. Analysis of the data that were collected confirmed the effectiveness of stable berms to prevent shoreline erosion, even in the event of large, episodic storms. Just as the Norfolk study was used in planning the Dauphin Island project, results from the Dauphin Island national demonstration project were used for other projects along the Atlantic,
Gulf, and Pacific coasts. Continued monitoring of these projects is providing further information on their performance relative to episodic storms.
It is sometimes necessary to implement pilot studies slowly. Experience shows that they must be carefully planned and executed so that data obtained are adequate for scientific and engineering analysis. Rushing a project to implementation may be at odds with the time frame needed to effectively collect a full range of scientific information about the site and project performance. Thus, projects that are urgently needed would not appear to be optimal candidates for pilot studies. Yet, even where a project is not optimal for supporting scientific research, it may nevertheless provide a unique opportunity to gain insights not feasible using laboratory experiments. Although the potential value of demonstration and pilot projects can be high if lessons from them can be broadly applied, they nevertheless tend to be expensive relative to the information gained, primarily because of both near- and long-term monitoring needs and associated costs.
Available technology can potentially be applied to a greater extent to benefit marine habitat through the use of alternative, non-tradition, and innovative solutions.
Alternative applications of available technology have sometimes resulted in the unplanned creation of valuable habitat and demonstrated that there may be a potential for broader, planned application of the technology. For example, the unplanned creation of waterbird nesting islands along the Gulf, Atlantic, Great Lakes, and Pacific coasts demonstrated the potential use of dredged material as a resource rather than as a waste (spoil). For example, artificially created nesting islands in North Carolina estuaries were originally mounds of material dredged for the purpose of maintaining navigation channels (Appendix B; Landin, 1992a). The islands then developed naturally, ultimately providing habitat suitable for a range of waterbirds and other nesting birds, including habitat for some threatened and endangered species. The successful colonization of these sites by waterbirds, although unplanned, demonstrated that the concept could be more broadly applied. In general, the subsequent creation of islands with dredged material in other locations, some done accidentally and some intentionally, has also provided waterbird nesting habitat. At the islands' present state of development, only a trained eye can distinguish these from natural islands. The general success of nesting islands suggest that other alternative, nontraditional, and innovative applications of technology may also be feasible, particularly as it relates to the use of dredged material in habitat protection and restoration work.
Habitat restoration (and sometimes creation) replaces one habitat type with another.
Restoration projects reestablish degraded habitats, albeit replacing one that is judged to be of inferior quality but that may be supporting or complementing habitat for a single species. Created habitats may or may not establish habitat at the expense of another, depending on prior use of a project site. For example, the creation of nesting islands for sea and wading birds discussed earlier and in Appendix B replaced deep water fish habitat with island and intertidal water habitat. The fact that habitat is converted from supporting some species to supporting others often creates competition between the missions and habitat interests of the various federal and state agencies responsible for habitat management. Similarly, even environmental groups may find themselves in conflict when favored species are threatened by or are not covered to their satisfaction in restoration and creation plans.
To prevent unintended and potentially devastating losses of critical habitat, a holistic ecosystem approach to management of marine habitat is required. Seagrass beds associated with coastal wetlands offer a safe haven for many juvenile fishes. A salt marsh restoration or creation can provide a source of nutrients to these juvenile fishes, but the marsh will be virtually useless if seagrass beds are lost during construction or thereafter through changes in water quality and hydrology. By working together, ecologists and engineers can identify critical habitat and plan measures to prevent habitat degradation and loss.
Flexibility in the planning and design of marine habitat protection and restoration projects to accommodate local conditions can improve the potential for successful outcomes.
What works in protection or restoration projects at one site may not work at another due to differences in local conditions. Examination of projects in different regions indicate that different approaches can be used effectively to restore vegetation as an element of marine habitat projects. Two successful habitat creation and restoration projects (Mississippi River delta and Pointe Mouillee, Michigan) allowed natural vegetation to colonize and without plantings. The Miller Sands, Oregon, project, on the other hand, required use of eight intertidal plant species to recolonize the site. These projects achieved revegetation objectives because the approach used was purposefully matched to local conditions.
When there are gaps in scientific data needed for decision making, expert local knowledge can be solicited. For example, incomplete planning during port development resulted in filling one shallow water area of Tampa Bay. Although the environmental sampling required under the permitting process was conducted, sampling for possible overwintering shrimp populations at the proposed fill site was not performed. Placement of fill to create industrial land resulted in the loss of some of the most important muddy bottom habitat for overwintering shrimp; 25 percent (1,200 of 4,800 acres) of the habitat for over wintering shrimp
was destroyed. This loss could have been avoided had project managers identified the presence of an existing commercial fishery and obtained local information (Appendix B).
Federal, state, and local policies geared toward marine habitat management influence project performance.
Federal, state, and local policies are generally seen both as a stimulus for coastal restoration and as impediments to habitat protection and restoration (Chapter 5). Without regulatory programs, there would be little impetus for mitigation and restoration aside from environmental advocacy. Policies having a positive influence include Florida's 1987 Surface Water Improvement and Management Act (SWIM) from which recent wetlands restoration projects in Tampa Bay benefited. The act established a dedicated restoration (and creation) program. SWIM efforts in Tampa Bay focused on the physical creation of lost habitats, such as wetlands and seagrass beds. Recognizing that their staff were not sufficiently experienced to design and supervise restoration projects, SWIM programs managers contracted with a multidisciplinary team. The ensuing comprehensive planning, design, and implementation resulted in all nine Tampa Bay projects' achieving project objectives.
Successes in marine habitat protection and restoration have often involved multidisciplinary collaboration; careful planning, design, and implementation; and long-term management strategies, including performance monitoring. Where project success has not been achieved, these same features were typically absent. Valuable lessons learned from both successful and unsuccessful projects can be applied in subsequent project planning, design, and implementation.