Summary

The acid test of our understanding is not whether we can take ecosystems to bits on pieces of paper, however scientifically, but whether we can put them together in practice and make them work.

A.D. Bradshaw, 1983

INTRODUCTION

Aquatic ecosystems perform numerous valuable environmental functions. They recycle nutrients, purify water, attenuate floods, augment and maintain streamflow, recharge ground water, and provide habitat for wildlife and recreation for people. Rapid population increases in many parts of the United States— accompanied by intensified industrial, commercial, and residential development— have led to the pollution of surface waters by fertilizers, insecticides, motor oil, toxic landfill leachates, and feedlot waste. At the same time that water pollution and releases of nutrient-laden municipal sewage effluents have increased, water consumption has also increased, thus reducing the flows available for the dilution of wastes.

Increased sediment delivery resulting from urban construction, agriculture, and forestry also has resulted in greater turbidity and sedimentation in downstream channels, lakes, and reservoirs, with attendant losses of water storage and conveyance capacity, recreational and aesthetic values, and quantity and quality of habitat for fish and wildlife. Increased demands for drainage of wetlands have been accommodated



The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement



Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.

OCR for page 1
Restoration of Aquatic Ecosystems: Science, Technology, and Public Policy Summary The acid test of our understanding is not whether we can take ecosystems to bits on pieces of paper, however scientifically, but whether we can put them together in practice and make them work. A.D. Bradshaw, 1983 INTRODUCTION Aquatic ecosystems perform numerous valuable environmental functions. They recycle nutrients, purify water, attenuate floods, augment and maintain streamflow, recharge ground water, and provide habitat for wildlife and recreation for people. Rapid population increases in many parts of the United States— accompanied by intensified industrial, commercial, and residential development— have led to the pollution of surface waters by fertilizers, insecticides, motor oil, toxic landfill leachates, and feedlot waste. At the same time that water pollution and releases of nutrient-laden municipal sewage effluents have increased, water consumption has also increased, thus reducing the flows available for the dilution of wastes. Increased sediment delivery resulting from urban construction, agriculture, and forestry also has resulted in greater turbidity and sedimentation in downstream channels, lakes, and reservoirs, with attendant losses of water storage and conveyance capacity, recreational and aesthetic values, and quantity and quality of habitat for fish and wildlife. Increased demands for drainage of wetlands have been accommodated

OCR for page 1
Restoration of Aquatic Ecosystems: Science, Technology, and Public Policy by channelization, resulting in further loss of stream habitat. This has led to aquatic organisms becoming extinct or imperiled in increasing numbers and to the impairment of many beneficial water uses, including drinking, swimming, and fishing. Although public and private decisions to manage aquatic ecosystems have enhanced water transportation, developed sources of hydroelectric power, reduced flood hazards, and provided water for municipal, industrial, and agricultural purposes, these activities have also altered the physical, chemical, and biological processes within aquatic ecosystems. This committee is convinced that U.S. public opinion strongly supports an increased level of attention to environmental protection. The nation's investment in different types of environmental programs has been considerable but piecemeal and has not always been effective. An accelerated effort toward environmental restoration and preservation is needed. The committee believes that a comprehensive and aggressive restoration component should be the centerpiece of such an effort. The premise of this report is that ecological restoration of aquatic ecosystems is possible. Restoration means returning an ecosystem to a close approximation of its condition prior to disturbance. Accomplishing restoration means ensuring that ecosystem structure and function are recreated or repaired, and that natural dynamic ecosystem processes are operating effectively again. At times, however, restoration may be impractical or undesirable, as when a body of water that is naturally without fish is successfully transformed through stocking into a valuable trout fishery or when important urban developments have been situated on wetlands. In such cases, the committee recognizes that the economic value of these developments may preclude any attempt to restore preexisting natural systems at these locations. The committee also recognizes that preventive measures to protect aquatic ecosystems are important and that priority should be given to preventive measures that benefit more than one portion of the hydrologic cycle. Had environmental protection been adequate in the past, many expensive restoration projects would not be necessary today. Naturally, restoration of aquatic ecosystems may be accomplished in stages, and particular ecosystem functions and characteristics— such as potable water— may be restored even when other ecosystem characteristics deviate from natural conditions. Thus, in certain situations, partial ecological restoration may be the operant management goal and may provide significant ecological benefits even though full restoration is not attained. Therefore, since the loss and impairment of aquatic ecosystems is

OCR for page 1
Restoration of Aquatic Ecosystems: Science, Technology, and Public Policy accompanied by loss and impairment of valuable environmental functions and amenities important to humans, and since restoration of aquatic ecosystems is possible, the committee concludes that a large-scale aquatic ecosystem restoration program in the United States should be implemented to regain and protect the physical, chemical, and biological integrity of surface water. Such a program should seek to: correct nonpoint source pollution problems; arrest the decline of wildlife populations; and restore all types of wildlife habitats with priority to endangered species habitat. Failure to restore aquatic ecosystems promptly will result in sharply increased environmental costs later, in the extinction of species or ecosystem types, and in permanent ecological damage. NATIONAL STRATEGY The committee recommends that a national aquatic ecosystem restoration strategy be developed for the United States. This comprehensive program should set specific national restoration goals for wetlands, rivers, streams, and lakes, and it should provide a national assessment process to monitor achievement of those goals. The following recommendations are proposed as building blocks for the program and its guiding strategy. Details of the program design should be developed by federal and state agencies in collaboration with nongovernmental experts. A national strategy would include four elements: National restoration goals and assessment strategies for each ecoregion (regions that have broad similarities of soil, relief, and dominant vegetation). Principles for priority setting and decision making. Policy and program redesign for federal and state agencies to emphasize restoration. Innovation in financing and use of land and water markets. Achieving these restoration goals will require planning, federal leadership, and federal funding, combined with financial resources and active involvement from all levels of government, as well as the involvement of nongovernmental organizations and businesses. Therefore, the federal government should initiate an interagency and intergovernmental process to develop the national aquatic ecosystem restoration strategy. The program should be developed and maintained under the firm leadership of a single responsible organization

OCR for page 1
Restoration of Aquatic Ecosystems: Science, Technology, and Public Policy with the characteristics stipulated in Chapter 8. Implementation of the program should include reliance on local and regional environmental restoration boards for program planning, synthesis, and leadership. Current appropriate federal programs should be reviewed to identify available opportunities for aquatic ecosystem restoration. CONGRESS In light of existing budgetary constraints, innovative ways to finance restoration efforts are necessary. Thus, Congress should establish a National Aquatic Ecosystem Restoration Trust Fund. Private landowners and corporations should be given powerful federal and state incentives to restore their aquatic ecosystems. Every effort should be made to use federal and other governmental funding to encourage citizen participation in restoration. Citizen participation (either through private citizen groups or public interest groups) has been instrumental in initiating and continuing restoration activities. In addition, Congress should allow states and local governments to trade in federal water development construction, maintenance, and major repair funds to finance aquatic ecosystem restoration programs. The Food, Agriculture, Conservation, and Trade Act of 1990 (P.L. 101– 624) authorized the U.S. Department of Agriculture (USDA) to enter into long-term contracts with farmers to take former wetlands in agricultural use out of production and allow them to be restored as wetlands. However, the act limits the number of acres eligible for the program to 200,000 per year, with a maximum of 1 million acres. Each acre of cropland taken out of production and restored as wetland is no longer eligible for USDA program benefits. Thus, Congress should request that USDA investigate where and how an expansion of the Agricultural Wetland Reserve Program would result in a savings of USDA farm program expenditures; and saved funds could then be reallocated to expand the wetland reserve program beyond 1 million acres. Any redirection of federal policies and programs for aquatic ecosystem restoration should take into consideration the following: use of a landscape perspective in restoration efforts; use of adaptive planning and management (this refers to analysis of alternative strategies, reviewing new scientific data, and reanalyzing management decisions); evaluating and ranking restoration alternatives based on an assessment of opportunity cost rather than on traditional benefit-cost analysis;

OCR for page 1
Restoration of Aquatic Ecosystems: Science, Technology, and Public Policy incorporating the definition of restoration as the return of an ecosystem to a close approximation of its condition prior to disturbance, in the mandates of all appropriate federal agencies; reliance on nonfederal and federal units of government to coordinate restoration programs in local areas; and initiating a interagency and intergovernmental process to develop a unified national strategy for aquatic ecosystem restoration. LONG-TERM, LARGE-SCALE, COORDINATED RESTORATION-PLANNING, EVALUATING, AND MONITORING Although restoration ecology applied to aquatic ecosystems is in a very early stage of development, the prospect for substantive improvements in damaged aquatic ecosystems is excellent. However, current federal and state environmental programs and policies are fragmented and do not adequately emphasize restoration based on management of large, interconnected aquatic ecosystems. The diverse responsibilities of all layers of government affecting aquatic resources need to be better coordinated if large-scale restoration is to be accomplished efficiently and effectively. Because aquatic ecosystems are interconnected and interactive, effective restoration efforts should usually be conducted on a large enough scale to include all significant components of the watershed. In addition, aquatic restoration efforts also need to be long-term to ensure that restoration project goals have been achieved and that restored ecosystems can endure stressful episodic natural events such as floods, droughts, storms, pestilence, freezing, heavy cyclical predation, invasion by exotics, and other perturbations. Because of limited resources, it is impossible in the short term to undertake all worthy aquatic ecosystem restoration projects. Criteria are thus needed to set priorities, select projects, and evaluate project designs. It is important to give priority to the repair of those systems that will be lost without intervention. A ''triage" framework needs to be applied as a minimum initial step. In this approach, threatened systems would be divided into three categories: (1) those that will recover without intervention, (2) those that cannot be restored to a meaningful degree even with extensive intervention, and (3) those that can be significantly restored with appropriate action. Systems in the third group require further consideration. Selections from that group should be based on criteria such as the likelihood of success, opportunity cost, and technical review of the restoration plan. It is imperative that these criteria be applied to the selection of projects because many restoration projects will not coincide with political boundaries.

OCR for page 1
Restoration of Aquatic Ecosystems: Science, Technology, and Public Policy Planning a restoration project must start with specifying the project mission, goals, and objectives. Goals should be prioritized so that project designers and evaluators have a clear understanding of their relative importance. In addition to specifying goals, objectives, and performance indicators, project managers and designers need to propose a monitoring and assessment program that is appropriate in scale as well as in sampling frequency and intensity to measure the performance indicators accurately and reliably, and thereby assess progress toward the project's objectives, goals, and mission. Postproject evaluation will enable scientists to determine when and to what degree the system has become self-maintaining and whether or not the restoration attempt was effective. Monitoring of a restoration effort should include both structural (state) and functional (process) attributes, and should not be restricted to one level of biological organization. Monitoring of attributes at population, community, ecosystem, and landscape levels is appropriate in a restoration effort. LAKES By far the most widespread problem facing lakes and reservoirs is agricultural nonpoint runoff of silt and associated nutrients and pesticides. Lakes often do not cleanse or restore themselves. They are sinks for incoming contaminants that recycle and maintain the impaired conditions. Federal drinking water standards, for example, cannot be met, except with great difficulty and expense, unless degraded lakes and reservoirs are improved and then protected from further contamination. A net gain over the next 20 years of 2 million acres of restored lakes, out of the current 4.3 million acres of degraded lakes, is an achievable goal. By the year 2000, it is recommended that a minimum of 1 million acres of lakes be restored. The costs for research, development, and technical guidance are federal responsibilities. The costs for actual restorations should be borne by federal and nonfederal sources, working through individual state lake programs. The committee realizes that the goals for the restoration of lakes should be realistic and tailored to individual regions of the country. Further development of project selection, goal setting, and evaluation techniques based on the concept of "ecoregions" as explained in Chapter 4 should be encouraged and supported by the U.S. Environmental Protection Agency (EPA). All states have degraded lakes, and each state should develop restoration

OCR for page 1
Restoration of Aquatic Ecosystems: Science, Technology, and Public Policy plans and programs. States should consider establishing trust funds for environmental restoration and protection. The Clean Lakes Program (CLP) administered by EPA has been the most reliable source of grant support for lake restoration efforts. This program should receive stable administrative support and increased funding from Congress. The 1991 appropriation for the CLP was $8 million. Although this amount will help to maintain or initiate a few lake restoration programs, it is inadequate for the large task of lake restoration facing the country. This program's mandate should be broadened to include all aspects of lake ecosystems, including habitat restoration, elimination of undesirable species, and restoration of native species. Knowledge of the current ecological condition of the nation's lakes is grossly inadequate, and a national assessment of lakes is necessary to determine the severity and extent of damage and to measure changes in their status. The CLP should increase support of research and development of effective tools for restoration, and should continue guiding states in developing lake restoration programs. The federal government should support research and development for demonstration watershed-scale restorations that integrate lake, stream, and wetland components. Research could be coordinated under an interagency program, such as the Federal Coordinating Council for Science, Engineering, and Technology, to coordinate the selection, planning, and evaluation of demonstration projects. Although many techniques are available to restore lakes, further development is required to improve their efficiency and effectiveness. The research and development programs in lake restoration should take an experimental approach, emphasizing controlled manipulation of whole-lake ecosystems or large in-lake enclosures. Research and development programs in applied limnology are needed to study improved techniques for littoral zone and aquatic macrophyte management; biomanipulation (food web management); contaminant cleanup in lakes, especially for mercury and polychlorinated biphenyls (PCBs); the relationships between loadings of stress-causing substances and responses of lakes; paleolimnological approaches to restoration; and prediction of lake trophic state from nutrient loading relationships.

OCR for page 1
Restoration of Aquatic Ecosystems: Science, Technology, and Public Policy RIVERS AND STREAMS Given that healthy, vegetated riparian habitat and bottomlands are essential to the natural ecological functioning of associated streams and rivers— and are among the nation's rarest habitats due to prior devastation— riparian habitat and bottomland restoration should be made a high national priority along with the restoration of the stream or river channel itself. Because a river and its floodplain are intimately linked, they should be managed and restored as integral parts of an ecosystem. Remnant and undisturbed large river and floodplain ecosystems are rare and ecologically valuable. Therefore, reaches of certain large rivers and their floodplain ecosystems (such as portions of the Atchafalaya River and the Upper Mississippi River Fish and Wildlife Refuge) and at least 50 other large rivers (greater than approximately 120 miles in length) should be designated as "reference reaches" for use as restoration templates and should be protected as quickly as possible. Reference reaches should be designated and protected on representatives of all orders of streams and rivers in each of the nation's ecoregions. Highest priority should be given to protecting representative orders of rivers and streams not already protected as national wild and scenic rivers, or by being located in national or state parks. Stream and river restoration should begin with improved land management practices that will allow natural restoration of the stream or river to occur. Therefore, the committee recommends the following: Erosion control programs in watersheds should be accelerated, not just to conserve soil, but also for the purpose of restoring streams and rivers. Grazing practices on federal lands should be reviewed and then changed to minimize damages to river-riparian ecosystems and to restore damaged rivers and streams. Erosion control by "soft engineering" approaches, such as bio-engineering techniques for bank stabilization and repair, should be considered first, in preference to "hard engineering" approaches, such as dams, levees, channelization, and riprap. Dikes or levees no longer needed or cost-effective should be razed to reestablish hydrological connections between riparian and floodplain habitats and associated rivers and streams. Classification systems for land use and wetlands should explicitly designate riparian environments and floodplains that retain their periodic connections to rivers.

OCR for page 1
Restoration of Aquatic Ecosystems: Science, Technology, and Public Policy The committee could not find a recent national assessment of the number of stream and river miles affected by channelization or leveeing, but the total is probably much greater than the number of miles of river dammed. Although water resources agencies track their own development projects, the only nationwide inventory of rivers and streams was conducted in the 1970s (DOI, 1982) in response to passage of the Wild and Scenic Rivers Act of 1968. Therefore, the committee believes there is a need for a comprehensive up-to-date nationwide assessment of rivers, comparable to the National Wetland Inventory. It would be very useful to know how many miles of free-flowing, unchannelized rivers remain in the United States, and where these reaches are located. The Food, Agriculture, Conservation, and Trade Act of 1990 and Section 404 of the Clean Water Act of 1977 (P.L. 95– 217) now encourage the restoration and protection of wetlands. These laws should be expanded to provide for the protection and restoration of large active floodplains and riparian zones that are key components of riverine ecosystems. In addition, the Conservation Reserve Program, the Environmental Easement Program, and short-term agricultural set-aside programs should be amended to ensure that riparian zones and floodplains of all kinds are eligible for inclusion along with wetlands. Opportunities to allocate water to in-stream uses arise (1) when land with water rights is sold or transferred, (2) when municipalities and irrigators decrease water withdrawals through conservation, and (3) when operating permits for dams are scheduled for renewal. Although the prior appropriations system (the basis of water law in the West) initially did not permit in-stream flow rights, many western states now recognize in-stream flow water rights. Therefore, states that have not established a water right for in-stream uses should do so. Flow that becomes available as the result of water conservation or lapse of permits should not automatically be reassigned to a consumptive use or withdrawal. Instead, consideration should be given to assigning the flow to in-stream uses. In addition, operating plans for dams should consider the annual water regime required by riverine fish and wildlife. Federal agencies should be requested to update channelization estimates and to estimate miles of bank stabilization work already performed. The agencies should provide average and mean costs per mile for construction and maintenance of these conventional river management strategies, so that unit costs are available for comparison of different strategies. Government agencies should also conduct post-project evaluations of fluvial modifications, enhancement, improvement, channelization, and restoration projects to determine whether

OCR for page 1
Restoration of Aquatic Ecosystems: Science, Technology, and Public Policy these projects actually achieve the benefits (e.g., flood protection, fish and wildlife enhancement) for which they were designed at costs that were projected. The committee also recommends that a national river and stream restoration target of 400,000 miles of river-riparian ecosystems be restored within the next 20 years. This target represents only about 12 percent of the total 3.2 million miles of U.S. rivers and streams, and is recommended because it is comparable to the miles of streams and rivers affected by point source and urban runoff (EPA, 1990). WETLANDS Historically, the most destructive alterations to wetlands have been physical, often eliminating the topographic and hydrologic characteristics that support the wetland ecosystem. Their position in the landscape, whether as isolated wetlands or floodplains contiguous with rivers and streams, gives wetlands a major role in storage of floodwater and abatement of flooding. When wetlands are converted to systems that are intolerant of flooding (drained agricultural lands, filled developed lands), their storage capacity decreases and downstream flooding occurs. Wetlands have properties of both aquatic and terrestrial ecosystems. Their most widely valued function is providing habitat for fish, birds, and other wildlife, which contributes to the maintenance of biodiversity. Controversy exists as to whether or not certain wetland systems can be restored. The arguments are particularly important when wetland restoration is undertaken with the promise that because full restoration of a degraded site is possible, other natural wetlands can be destroyed without any net loss of wetland habitat. Wetland restoration should not be used to mitigate avoidable destruction of other wetlands until it can be scientifically demonstrated that the replacement ecosystems are of equal or better functioning. Funding priority should be given to programs for restoration of damaged wetlands over wetlands creation because of the superior chances of success. An exception would be cases in which restoration is part of a mitigation agreement that would result in a net loss of acreage. Wetlands restored in regulatory contexts often receive little management after initial restoration because private and public landowners, who are not motivated to provide such management, may move on or have no legal obligation for such management. Similarly, the responsible federal agencies do not have staff to assess the adequacy of restoration projects and do not monitor or require monitoring of permit mitigation conditions for sufficient time periods (10 years or

OCR for page 1
Restoration of Aquatic Ecosystems: Science, Technology, and Public Policy longer). As a result, such wetlands may be overrun by exotic species, quickly filled by sediment, polluted, or otherwise misused. The practice of wetland restoration needs to move from a trial-and-error process to a predictive science. The following recommended practices should be applied by resource managers to wetland restorations: Strive to restore wetland to self-sustaining ecosystems requiring minimal maintenance. Provide buffers to protect restored wetlands, ensuring that restored coastal wetlands have room to migrate inland as long-term increases in sea level occur. Develop innovative methods of accelerating the restoration process (e.g., better propagation techniques for native plant species and protocols for obtaining adequate genetic diversity in the transplant material), and establish regional and national data bases to provide comparisons of the natural functioning of different wetland ecosystem types in different regions. Design and conduct experimental research programs to examine wetland restoration techniques and functional development over time in different system types. Use wetland restoration sites for scientific experiments that are designed to accelerate the restoration process. Support baseline studies of wetland ecosystem functioning to provide comparisons of different wetlands types among regions and at different stages of development. The hydrologic needs and requirements of wetland plants and animals, including minimum water depths, hydroperiod, velocity, dissolved nutrients, the role of large-scale but infrequent events, such as floods, and the effects of long-term fluctuations in water levels. The importance and functional significance of substrate to wetland plants and animals and to chemical and biological functions. Characteristics of development rates for natural successional vegetation. Recolonization of restored sites by invertebrate and vertebrate fauna. Functions of wetlands, with special emphasis on habitat values for a broad range of species, food chain support, and water quality enhancement.

OCR for page 1
Restoration of Aquatic Ecosystems: Science, Technology, and Public Policy Evaluation of the stability and persistence of wetland ecosystems. Evaluation of the impact of sediment deposition or erosion, nutrient loading or removal, toxic runoff, pedestrian and off-road vehicle use, grazing, and other impacts on wetland structure and function. The ability of microbes, which are important to global carbon, sulfur, and nitrogen cycles, to perform these roles in restored wetlands. The committee recommends that inland and coastal wetlands be restored at a rate that offsets any further loss of wetlands and contributes to an overall gain of 10 million wetland acres by the year 2010, largely through reconverting crop and pastureland and modifying or removing existing water-control structures. This represents a tenfold increase in the wetlands restoration target included in the Agricultural Wetland Reserve Program of the Food, Agriculture, Conservation, and Trade Act of 1990. This number also represents less than 10 percent of the total number of acres of wetlands lost in the last 200 years. The committee further recommends that, in the long term, this acreage be expanded to restore more of the approximately 117 million acres of the wetlands that have been lost in the United States over the past 200 years. EDUCATION AND TRAINING To accomplish the preceding tasks, the nation will require resource management professionals with multidisciplinary training. Restoration of aquatic ecosystems requires an integrated, broad-based approach; those trained to help restore these systems must have an interdisciplinary education. Although specialization will still be necessary, professionals will need the ability to coordinate work that draws on aquatic biology and fisheries, chemistry, hydrology, ecology, fluvial geomorphology, hydraulic engineering, social sciences, and wildlife management. Some well-intentioned restoration projects have failed because fluvial and biological processes were not adequately taken into account in their design and implementation. The public has become increasingly aware of the need for restoration of river-riparian ecosystems (as several case studies in Appendix A indicate), and numerous public and private agencies and citizen groups are likely to initiate further stream and river restoration projects. These organizations, if properly guided and supported, can be a valuable impetus for effective

OCR for page 1
Restoration of Aquatic Ecosystems: Science, Technology, and Public Policy aquatic ecosystem restoration and, in some cases, a valuable source of volunteer labor to accomplish restoration. A new emphasis on resource stewardship and restoration cannot succeed without public understanding and support. Thus, educational programs aimed at raising the level of public knowledge and comprehension of aquatic ecosystem restoration rationales, goals, and methods should receive adequate government funding. The committee believes that hydrological advisory services should be operated by states or federal agencies to provide technical assistance to groups interested in stream and river restoration. Universities with experts in natural resources or hydrology and water resources institutes, based at universities in every state, also should contribute technical assistance required for the restoration of aquatic ecosystems through free or at-cost expert hydrological and biological advisory services. CONCLUSION Without an active and ambitious restoration program in the United States, our swelling population and its increasing stresses on aquatic ecosystems will certainly reduce the quality of human life for present and future generations. By embarking now on a major national aquatic ecosystem restoration program, the United States can set an example of aquatic resource stewardship that ultimately will also improve the management of other resource types and will set an international example of environmental leadership. REFERENCES Benke, A.C. 1990. A perspective on America's vanishing streams. J. Am. Benthol. Soc. 9(1):77–78. Bradshaw, A.D. 1983. The reconstruction of ecosystems. J. Appl. Ecol. 20:1– 17. Clean Water Act of 1977. P.L. 95– 217, Dec. 27, 1977, 91 Stat. 1566. Food, Agriculture, Conservation, and Trade Act of 1990. P.L. 101– 624. Kusler, J.A., and M.E. Kentula, eds. 1989. Wetland Creation and Restoration: The Status of the Science. Vol. I-II. U.S. EPA/7600/3– 89/038. U.S. EPA Environmental Research Laboratory, Corvallis, Ore. U.S. Department of the Interior (DOI), National Park Service. 1982. The Nationwide Rivers Inventory. U.S. Government Printing Office, Washington, D.C. U.S. Environmental Protection Agency (EPA). 1990. The Quality of Our Nation's Water. EPA 440/4– 90– 005, Washington, D.C.