Applied and basic research has provided considerable technical information to aid in marine habitat protection and restoration—in addition to the wealth of documentation for specific projects and technology applications. Yet, the results of basic and applied research are not always readily available; nor do they appear to be well utilized in marine habitat management.
RESEARCH PROGRAMS RELEVANT TO MARINE HABITAT MANAGEMENT
Marine habitat research has been driven primarily by related missions of federal and state agencies. The research was sponsored to support these missions by improving the capabilities needed to meet assigned responsibilities. Some of the research was conducted by laboratories and field research facilities maintained by the U.S. Army Corps of Engineers (USACE), the National Marine Fisheries Service (NMFS) and National Oceanic and Atmospheric Administration (NOAA), the U.S. Forest Service (USFS), the Soil Conservation Service, the U.S. Fish and Wildlife Service (USFWS), the Environmental Protection Agency (EPA), and the Department of Energy (DOE). Most federal agencies with responsibilities for coastal zone or marine habitat management and the National Science Foundation also sponsor extensive basic and applied research under contract with colleges, universities, private foundations, businesses, and sister agencies. For example, the Army Corps of Engineers' water resources,
navigation, and, more recently, wetlands regulation missions are prime directives and funding sources. Thus, it not only conducted research but also provided research funds for other agencies, academia, and private organizations. Under existing federal and agency policies, most of this research is oriented toward practical application, and is holistic in nature (WES, 1992). Most basic coastal research using federal funds may be sponsored only to the degree that the resulting product can be used for an applied purpose.
State and Private Programs
Some coastal states have active research programs that include cooperative efforts under the Sea Grant Program, marine experimental stations and extension services, and sponsorship of research facilities and consortia with colleges and universities. Some conservation organizations sponsor or conduct research applicable to marine habitat management.
Companies engaged in restoration or dredging sponsor or conduct virtually no basic and little applied marine habitat protection and restoration research although applied research may be a component of projects with which they are involved. Despite its prominence in the coastal engineering profession, the dredging industry follows rather than leads the market for developing and implementing innovative technologies. Some innovation is occurring within the limits of existing technology, but the industry has not invested in research and development of technology intended for use in marine habitat management. Its position is that if a need for new technology is identified and there is an economically viable market for its use, then the industry will either develop the technology or transfer it from international applications. The U.S. marine habitat restoration market, insofar as it pertains to use of dredged material, is viewed as too small to justify investing in specialized dredging or dredged material placement technology.
Colleges and universities with strong coastal identities and research components conduct much of the basic research pertaining to marine habitats. Although their funding is generally from federal and state public agencies, academia has covered a broad range of research needs. The result is that substantial information relevant to habitat protection and restoration is available to the technical community, but not always conveniently or readily.
Considerable basic ecological research is sponsored by NOAA's Sea Grant Program. Results are routinely published and available from state offices of Sea
Grant. There is generally no national distribution although publications are sometimes announced in newsletters and professional journals.
Basic research conducted by federal agencies includes several decades of intertidal research in the Savannah River estuary by the DOE's Savannah River Ecology Laboratory; NMFS work involving seagrass and fisheries species (Thayer, 1992); USFWS basic research on coastal species management; USFS basic research on marine habitats; and USACE work on the long-term fate of dredged material, long-term monitoring (environmental and engineering), contaminated sediments, equipment, structures, engineering technology, wetlands, habitat restoration, and critical processes. Extensive documentation is available covering most Army Corps of Engineers research.
In addition to other federal agencies that conduct basic research of interest to marine habitat management, the EPA and the Federal Highway Administration (FHA) conduct applied research. EPA is administering a 5-year, $10 million Wetlands Research Program. Although the program has a regulatory focus, the EPA is broadening it beyond research relevant to Section 404 of the CWA to correspond with a broadening of the agency's role and interests in marine and other habitats (Mary E. Kentula, EPA Corvallis, Oregon, personal communication, March 16, 1992). In addition, EPA's Superfund responsibility, which includes coastal sites, may provide an opportunity to include coastal habitat research. The FHA administers a major applied research program applicable to land transportation infrastructure in the coastal zone, where wetlands may be impacted (Charles DeJardine, FHA, personal communication, October 3, 1992).
The Army Corps of Engineers has a substantial investment in research capabilities and applied research. In 1973, the Corps established the Dredged Material Research Program, which has been carried forward to five other research programs, each with separate funding: Dredging, Dredging Operations Technical Support, Environmental Effects of Dredging, Long-term Effects of Dredging Operations, and Dredging Research Programs. Each has strong engineering and environmental components requiring multidisciplinary cooperation and teamwork. More than $150 million has been allocated to these programs over the past 20 years. During the late 1970s, in response to the agency's wetland regulation responsibilities, the Corps of Engineers initiated its Wetlands Research Program. Although it is intended to support regulatory actions, since 1990 the program has been expanded to include multidisciplinary and multipurpose applied research; $22 million has been committed to these efforts through 1994. Currently one third is directed to wetland protection, restoration, and creation. About one-half of these research projects are being conducted in the coastal zone. The Corps of Engineer's restoration research overlaps considerably with its research to encourage
substantially more frequent use of dredged material as a resource (Landin, 1991).
The NMFS and USFWS are both actively involved in pertinent applied research: the NMFS Coastal Habitat Restoration Program (Thayer, 1992) and the USFWS North American Waterfowl Management Plan (Robert Misso, USFWS, personal communication, March 17, 1992). In addition, the Soil Conservation Service has both Conservation Reserve and Wetland Reserve Programs, while, although not specifically research oriented, are positioned to work with and use research information from other agencies to implement habitat restoration (B.M. Teel, SCS, personal communication, March 19, 1992).
Many federal research programs involve federal and, in some cases, state agencies with interests in marine habitat management. Because of the many agencies involved and their different missions and responsibilities, overlap and redundancy of effort as well as inefficient technology transfer are inevitable. Recently, in the face of budget austerity and national level interest in habitats generally, there have been efforts to improve the efficiency of research programs through interagency coordination. As an example, in 1989, 12 federal agencies with wetland responsibilities established a permanent interagency committee to improve their wetlands research programs. Information on federal-level wetlands research, including funding, was compiled in a public report as part of the committee's findings (WES, 1992). Although these efforts to prevent redundancy and overlap were only partially successful, they made progress in providing a more thoughtful and systematic wetlands research agenda. This approach could be used for research supporting marine habitat management.
New opportunities may develop for interagency coordination under the Coastal America Program. It is an interagency initiative to improve the stewardship of coastal resources by effectively addressing habitat degradation and loss, nonpoint source pollution, and contaminated sediments. A consortium of federal agencies made a substantial investment of resources in formulating the initiative. Its implementation and long-term support are yet to be demonstrated.
Leadership of federally sponsored restoration research is not yet established. The USACE, the NMFS, the USFWS, and the EPA are interested in a central role in setting coordinated research agendas (Thayer, 1992). The agencies are reluctant to relinquish directive authority and discretionary capabilities to other agencies or administrations because of concerns about competing interests, perspectives, and focus as well as about funding. Assessment of agency capabilities to lead or coordinate a national research agenda for marine habitat protection and restoration is beyond the scope of this report.
Although completed research covers a wide spectrum of engineering and environmental needs in the coastal zone, including multidisciplinary cooperation in research, not all important areas are well-addressed. Some involve crossover research efforts that require multidisciplinary teams, especially in wetlands restoration. But the research in these areas has been sporadic, limited in funding and sometimes in scope.
Despite the considerable applied research, understanding the basic processes affecting marine and other coastal habitats is the least developed. The gaps in knowledge about baseline habitat requirements and species interactions within coastal ecosystems are substantial. Much is known about some life requirements of some commercially important fish species, but less is known about the organisms on which they feed and other components of their ecosystems that allow survival or stress the species. These gaps not only affect the efficacy of engineering and environmental practices but also influence research on structures, biological techniques, equipment, and technologies for habitat protection and restoration. Existing coastal engineering technologies provide a relatively substantial capability, but they do not meet specialized restoration needs. Engineering gaps include specialized equipment and methodologies for placement and stabilization of construction materials in marshes and intertidal habitats, structural design, use of soft sediments as substrate materials, and the locking of contaminants in sediments to prevent habitat degradation. Advances in each of these areas could advance the state of practice in protecting and restoring marine habitats. Excess sediments and contaminants that adversely affect water quality and marine habitats also need to be addressed at their source within affected watersheds. Otherwise, the full benefits of advances in protection and restoration technologies will likely not be realized in some areas.
ENVIRONMENTAL TECHNOLOGY NEEDS
The four key technical components in marine habitat restoration are soils and substrates, hydrology (for wetlands), vegetation, and energy. When they are adequately satisfied, the aquatic and wetlands habitat conditions will be appropriate for colonization of the particular habitat by vertebrates and invertebrates. The presence of these animals is essential to restoring and sustaining natural functions. The technical components must all be effectively understood, addressed, and accommodated for restoration efforts (and use of marine habitat as shoreline protection) to succeed. Determining how to achieve optimal hydrology, which plant species and propagules to use, what elevations are appropriate, what physical, chemical, and biological soil components that affect habitat productivity are necessary, and how to deal effectively with the physical energies that influence a habitat is not well established for all coastal habitat types. A
better understanding of each component and its collective implications would provide a more complete scientific basis for practical application of restoration technologies. Specific areas for research are described below.
Soils and Substrates
Coastal soils may include many variables, including textures ranging from clays, sand, shell, and rock rubble. The physical means of working with these soils to form them into suitable substrates for marine habitat restoration is limited. Needed soil-related research includes:
conversion of bottom sediments and upland soils to suitable substrates for intertidal habitats;
transportation and storage of hydric soils;
care and protection of seed banks;
consolidation and settling properties;
characteristics and origins of soils;
placement technology for all habitat types; and
suitability of foundation materials.
Applied restoration research on plant materials includes some life-cycle requirements work on dominant intertidal marshes and other intertidal vegetated habitats. However, significant gaps include:
species hardiness and adaptability;
ease in propagation and transplanting for restoration purposes;
long-term stability of substrates and plant communities;
invasion potential (and eradication techniques, when required
the suitability of plant communities to provide attractive habitats for fish and other organisms; and
use of native versus introduced species.
Fonseca (1990, 1992) identified the following specific research needs for seagrasses:
Definition and evaluation of functional restoration of seagrass beds.
Compilation of population growth and coverage patterns in all regions to better define growth patterns.
Evaluation of the resource role of mixed species plantings.
Investigation of impacts of substituting pioneer for climax species in transplanting on a compressed successional basis.
Refinement of culture techniques for propagule development.
Optimization of transplant techniques, with emphasis on the use of fertilizers.
Investigation of the importance of maintaining genetic diversity for restored beds.
Standardization of site evaluation methodologies.
Physical Energy Systems
The physical energy affecting marine habitats is usually derived from winds (wave and coastal currents), currents (tidal or river), and wakes. All are affected by bathymetry and any energy-dampening features around or near the habitat. Technology is sufficiently advanced to predict performance of some marine habitat restorations under conditions of low physical energy. Some research conducted over the past 30 years has addressed the use of bioengineering in sites exposed to moderate physical energy. However, significant gaps remain. Research on sites exposed to high physical energy is limited, and it remains difficult to restore habitats at these sites without major protective structures. The use of geotextiles has met with some success but is not widely applied except to hold hydraulically placed sediments or for shoreline protection (PIANC, 1992b). Underwater berms are used more extensively. Neither their effectiveness in attenuation of physical energy relative to protecting coastal habitats nor their capacity to create more favorable conditions for restoration has been established, although some are functioning well as artificial reef habitat. In some instances, existing currents may be used to distribute dredged sediments to create coastal wetlands. A better understanding of the effect of energy systems on habitat could expand opportunities for restoration in areas of moderate and high physical energy.
Social and economic considerations are often treated as secondary or minor to the more technical disciplines of environmental and coastal engineering. Yet socioeconomic factors are typically critical to the approval, authorization, appropriations, and acceptance of protection and restoration projects. A major gap is the inability to place a value on habitats that can be equated to the value of alternative uses. As a result, the environmental and economic benefits of habitats are typically valued at less than the alternative uses. For example, it is well known that marine habitats are essential for nearshore commercial finfish and shellfish populations. Yet there is no accepted methodology for establishing the value of each acre of habitat relative to fisheries populations, whereas the economic value of an industrial development can be projected and quantified (although not always accurately). An accepted methodology for determining the economic value of habitat and the collection of data to support such analyses are
gaps that could be filled by basic research. This research could draw on previous studies that have attempted to measure the benefits associated with protection of wetlands ecosystems (Anderson and Rockel, 1991; Batie and Mabbs-Zeno, 1985; Batie and Shabman, 1982; Batie and Wilson, 1979; Bell, 1989; Bergstrom et al., 1990; Brown and Pollakowski, 1977; Costanza et al., 1989; Farber, 1987, 1988; Farber and Costanza, 1987; Kellert, 1984; King, 1991; Lynne et al., 1981; Raphael and Jaworski, 1979; Shabman et al., 1979; Shabman and Batie, 1978; Shabman and Bertleson, 1979; Skaggs and McDonald, eds., 1991; Thibodeau and Ostro, 1981; Tschirhart and Crocker, 1987).
ENGINEERING TECHNOLOGY NEEDS
Principal gaps in engineering technology as it pertains to marine habitat management relate to precise placement and stabilization of dredged material, geotextiles, specialized equipment, structural design, contaminated sediments, and multipurpose applications, described below.
Placement and Stabilization of Dredged Material
Methods for using sandy sediments have generally been developed and refined. They are used in beach nourishment, for wildlife islands, and as substrates for wetlands and other habitats, although this latter use is sometimes controversial because of changes caused in local environments. Methods for effective use of clay and silt sediments (or sand, clay, and silt mixtures) have not been adequately researched. These soft substrates are rich in nutrients, and once stabilized, they can provide for abundant growth and productivity of coastal organisms. The key word is stabilization. Coastal engineers already know how to confine soft sediments. Substantial gaps for clays and silts exist in capabilities for:
environmentally compatible use in habitat restoration;
consolidation without confinement;
bringing them out of suspension when needed to stimulate more rapid marsh or mud flat formation;
formation of artificial reefs and berms;
prevention of their loss into the vast ocean system; and
locking in contaminants to reduce biomagnification.
Basic research in these areas would require multidisciplinary collaboration. Considering that about 300 million cubic yards of dredged material are dredged annually in the United States, improved capabilities to use dredged clays and silts in habitat protection and restoration could change much material that is disposed of into a valuable resource.
A companion technology to improved stabilization techniques is geotextile fabric. The use of geotextiles in water resource management has expanded rapidly. In the past 15 years, the technology has advanced from 10-by-4-foot nylon bags filled with in situ sand to prevent erosion and hold back unconsolidated sandy sediments, to more flexible sand-filled Longard tubing up to 100-by-4-foot lengths laid on the estuary floor, to customized geotextile barriers up to 6 feet in diameter (PIANC, 1992b). These largest geotextiles can contain areas of up to 25 acres using pressurized and packed silt material as filling and have up to a 30-year life. The Army Corps of Engineers is field testing the latest generation of geotextiles, but the use of this technology in restoration is not widespread. There appear to be substantial opportunities for innovative use of geotextiles in protecting marine habitats, particularly with regard to erosion control, shoreline stabilization, and dredged material placement.
Some of the new equipment for dredged material placement has have not been fully tested in a wide variety of field conditions. Equipment must function without causing more harm than good to fragile environments. Innovative placement technologies developed overseas (especially in Germany, the Netherlands, and Australia), could potentially satisfy this need. But there is little impetus for technology transfer. Studies and field tests would establish whether the technology could be adapted for use in marine habitat management.
Coastal engineering structures were traditionally designed to interact with and effect coastal processes to prevent erosion and stabilize shorelines. Such structures are generally not designed, constructed, or systematically evaluated for their effects on marine habitat. Nonetheless, the effects can be profound, particularly for circulation patterns and sediment transport. The engineering of the lower Mississippi River to maintain navigation channels and the construction of levees for flood protection, for example, resulted in sediment starvation of marshes. Installation of water control structures and selective breaches in levees to provide for natural replenishment of marshes have demonstrated that there is room for innovation in traditional engineering structures. Traditional coastal engineering structural applications could be examined to determine whether and to what degree design rules can be modified to minimize impacts on various marine habitats. The potential of coastal engineering structures in habitat protection could also be assessed.
Placement and Handling of Contaminated Sediments
The traditional technology for placement of contaminated sediments is confinement. But removal of sediments can release contaminants into the sediment transport stream and thus into ecosystems. Removal and placement of contaminated sediments, followed by capping with clean sediments, have been attempted in only two U.S. harbors (Landin, 1988a). More extensive work is constrained by uncertainties over the risk associated with the contaminants and their potential effects on ecosystems. Improvements in environmental risk assessment testing capabilities and assessment methodologies are indicated (Cairns and McCormick, 1992; Simmonds et al., 1992; Stout and Streeter, 1992).
Keeping contaminated sediments saturated by keeping them under water has proven best under laboratory and field test conditions to prevent mobility and environmental biomagnification (Lee et al., 1978, 1985; NRC, 1987b; NRC, 1989a; Scott et al., 1987; Simmers et al., 1986). Whether contaminants could be locked into sediments to prevent these adverse environmental effects, whether they could be decontaminated, and if they could, whether there are opportunities for beneficial use in marine habitat management have not been established. Research in this area is of interest insofar as environmentally safe dredging and placement could prevent damage to marine habitats in a system where contaminants have been deposited. The primary motivations for research, it should be noted, are not potential uses in protection or restoration, but management of those contaminated sediments that threaten environmental quality or that need to be moved for navigation projects in an environmentally safe way.
Multipurpose applications are those that are intended to serve ecological as well as social objectives such as shoreline protection, recreation, and public education. These applications generally involve either the use of bioengineering (the coupling of engineering technology with living plant material) or construction of multipurpose habitats using engineering technology. Bioengineering can be applied in habitat creation or restoration and for shoreline protection. When applied to shoreline protection, there may be ancillary benefits in the form of habitat. However, establishment of full natural functioning might not be an element of design, and might not be technically possible at some locations. Bioengineering has been attempted on a limited scale to stabilize shorelines. Maryland, Texas, and some other states technically and financially assist private landowners in using bioengineering as a natural alternative to structures, such as bulkheads. The largest bioengineering applications have been attempted in reservoirs (Allen, 1988, 1990; Allen and Klimas, 1986; Hammer, 1989). Results and several field tests in coastal locations indicate a broader potential for use of this technology to provide natural protection of shorelines in moderate wave energy
coastal areas (Allen, 1988, 1990, 1992). Bioengineering use costs about 75 percent less than physical structures. Because habitat is created and costs are reduced, further development of bioengineering could substantially advance the state of practice, particularly private owners' application to some shorelines. Bioengineering applications developed in Europe and Australia but not yet tested in the United States could be assessed.
Creating or restoring diverse habitats using engineering technology is not a new concept. Diverse habitats offer a variety of essential life-requirement opportunities for various species including both fish and wildlife. Diverse habitats are thus preferable to habitats designed to support only a few species, although the latter may be the only option in some locations due to local conditions. Currently research in this area is limited. Emphasis in recent years has been on wetlands. However, declining stocks of important commercial fishes that depend on a range of marine habitats suggest the need for more attention to ecosystem requirements, including wetlands but not excluding other habitat types found in water bodies, adjacent uplands and islands, and river system and watersheds supplying water and sediments to coastal estuaries.
Marine habitat management research is multidisciplinary in nature and interagency in scope. There are needs for both basic and applied research regarding scientific knowledge and engineering capabilities. A better understanding of coastal processes and baseline information on coastal biota, soils, vegetation, water quality, and other scientific parameters are essential to advancing restoration practice. Likewise, engineering requirements for shoreline stabilization, erosion control, coastal energy, dredging, and dredged material placement are important and timely. Technology transfer is lagging behind research results and technology application. To advance the state of practice, emphasis could be placed on protection and restoration of marine habitats under existing research programs. An umbrella organization could be established to coordinate the federal research agenda. Alternately, a lead agency could be assigned to guide the national research effort.