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Publication Number:      Date:  Jan/Feb 2001
Issue No: Vol. 64 No. 4
Date: Jan/Feb 2001


Preservation of Wetlands on The Federal-Aid Highway System

by Kirstyn White


Wetlands are vital natural ecosystems for a large variety of animals and plants, yet they are rapidly being converted or altered for other land uses. The Federal Highway Administration (FHWA) is committed to doing its part to ensure the protection and enhancement of wetlands. And FHWA's part is to make sure that the federally funded highway program results in an overall net gain of wetlands.

This isn't always an easy role. A wide variety of biological community types are classified as wetlands, and therefore, it is difficult to get a clear consensus of what constitutes a wetland. Part of that difficulty arises from the fact that "wetland" has come to be a legal - rather than a biological or ecological - term.

The National Academy of Sciences Wetland Characterization Committee defined a wetland as "an ecosystem that depends on constant or recurrent, shallow inundation or saturation with water at or near the surface of the substrate." Common diagnostic features of wetlands are moist soils and aquatic vegetation. Fresh water and estuarine marshes, fens, bogs, prairie potholes, and swampy forests are all considered wetlands.

The value of wetlands has often been overlooked in the past. They are instrumental in reducing flooding by acting as reservoirs for rainwater and runoff, controlling erosion, and improving water quality. Wetlands help to improve water quality by acting as a natural pollution control. They remove nutrients, pesticides, and sediments from surface waters, and they can help in treating sewage and animal waste.

Wetlands are best known as nesting, breeding, and feeding grounds for millions of waterfowl, birds, and other wildlife. Wetlands have been called "the richest and biologically most productive habitats on Earth." They provide a habitat for half the fish, one-third of the birds, one-fourth of the plants, and one-sixth of the mammals on the list of threatened and endangered species in the United States.

In addition to all of this, wetlands provide humans with a place of beauty and recreation. Many people enjoy hunting, fishing, bird watching, and photography in wetland areas. Wetlands are special places, and they require a cooperative effort to preserve them for the future.

During the 1930s, public awareness about the value of wetlands grew due to endangered species activists and sportsmen. They recognized the importance of wetland ecosystems, and as a result, Congress enacted a federal law that required waterfowl hunters to purchase hunting permits, commonly called duck stamps. The proceeds from the stamps went directly toward purchasing wetlands for waterfowl habitats.

A major piece of legislation for wetlands protection came in 1972 as amendments to the Federal Water Pollution Control Act (FWPCA) of 1948. FWPCA began a long effort to reverse the trend of wetland loss and to clean up our lakes, rivers, and coastal waters. It also established new regulations for the discharge of pollutants into waters of the United States.

In 1977, FWPCA was amended again and renamed the Clean Water Act (CWA). These amendments established additional wetland protection measures. CWA's main objective is to "restore and maintain the chemical, physical, and biological integrity of the nation's waters." Then in 1987, additional amendments were added to strengthen the requirements for discharges of storm water, to develop new management approaches, and to begin regulation of the discharge of runoff from construction sites.

Another major change in wetland protection came in 1977, when President Jimmy Carter issued Executive Order 11990 on the "Protection of Wetlands." This order rescinded the official policy of federal assistance for wetlands conversion and directed agencies to ensure that their regulations minimized effects on wetlands.

Then, in 1986, Canada and the United States entered into an agreement called the North American Waterfowl Management Plan. The plan was set up to restore waterfowl populations by protecting and improving wetlands and grasslands. Mexico joined the plan in 1994. The plan focused on helping landowners manage their lands in ways that benefited both them and the waterfowl.

In 1987, the National Wetlands Policy Forum, sponsored by the U.S. Environmental Protection Agency, advanced protection of wetlands in the United States and addressed major policy concerns in this area. The major goal of this group was to promote a national policy to ensure "no overall net loss of the nation's remaining wetlands base, as defined by acreage and function, and to restore and create wetlands, where feasible, to increase the quantity and quality of the nation's wetlands resource base."

The federal government and several states have adopted this goal. Former President Bush made this goal his main environmental promise, and FHWA adopted this policy and established performance goals for "no net loss" in federally funded programs for highway projects and construction.

The Clinton administration, on Aug. 24, 1993, announced new policies on wetlands issues (see http://www.epa.gov/OWOW/wetlands/plan/4years.html). These policies focused on long-term gains as well as "no net loss" in the short term. The policies pertain to using advanced science to define and delineate wetlands, improving the regulatory program, encouraging non-regulatory options, and expanding partnerships in wetlands protection.

Compensatory wetland mitigation is a process that focuses on enhancement, restoration, and creation or preservation of wetlands to compensate for unavoidable wetland losses. This concept came about at the National Wetlands Policy Forum during the summer of 1987. The concept of compensatory mitigation developed mainly as a result of deficiencies in the implementation of the Section 404 permit program of the Clean Water Act. To be granted a permit by the U.S. Army Corps of Engineers, an individual must prove that he has taken the appropriate steps to avoid effects on wetlands if possible, has minimized the unavoidable potential effects on wetlands, and has provided compensation by restoring or creating wetlands.

The ratio of wetland acreage created or restored to wetland acreage lost to development is called the mitigation ratio. This ratio depends on the acreage, functions, and values of the wetlands lost and the type of mitigation proposed. Ratios for compensatory mitigation are typically in the range of 1-to-1 to 1.5-to-1 for restoration, up to 2-to-1 for creation, and 3-to-1 for enhancement.

The Clean Water Action Plan, initiated in February 1998, sets national goals for restoring and protecting the nation's precious water resources. This plan calls for an increase of 100,000 wetland acres (40,470 hectares) by 2005. FHWA has committed itself to achieving a 50-percent increase in wetland acreage resulting from federal-aid highway projects in 10 years.

FHWA's Strategic Plan calls for the protection of the natural environment by ensuring mitigation through the Federal-Aid Highway Program. One of the goals of the plan specifies that wetland acreage will increase by 50 percent from 1996 to 2006. The plan establishes performance goals to ensure the achievement of this strategic goal. The required replacement ratio for the Federal-Aid Highway Program during fiscal years 1996 and 1997 was 1-to-1. In 1998, when the Clean Water Action Plan was developed, the replacement ratio was increased to 1.5-to-1 - for every acre (0.4 hectare) impacted, 1.5 acres of mitigation were provided.

FHWA began monitoring wetlands loss and gain nationwide under the Federal-Aid Highway Program in 1996. Monitoring began as a way to measure the performance of FHWA's net gain policy. Over the past five years, the program has averaged a ratio of 2.7-to-1 in acres of compensatory wetland mitigation to each acre of unavoidable impact.

As another means of evaluating data, FHWA developed the Wetlands Accounting Database. The database is designed to accumulate data about wetland mitigation projects. It collects, correlates, and presents this data as useful and meaningful information.

According to this data for the five-year period 1996 through 2000, the Federal-Aid Highway Program has produced a total net gain of 14,846 acres (6,000 hectares) of wetlands.

Fiscal Year Acres of Compensatory

Wetlands Mitigation

Acres of Wetlands


Mitigation Ratio/

Percent Increase

Net Acreage Gain
1996 3,554 1,568 2.3:1 / 130% 1,986
1997 4,484 1,699 2.6:1 / 160 % 2,785
1998 2,557 1,167 2.2:1 / 120 % 1,390
1999 5,409 2,354 2.3:1 / 130% 3,055
2000 7,671 2,041 3.8:1 / 280% 5,630
Totals 23,675 8,829 2.7:1 / 170% 14,846

Wetland mitigation banking is the restoration; creation; enhancement; or, in exceptional cases, preservation of wetlands or other aquatic resources expressly for the purpose of providing compensatory mitigation in advance of authorized impacts to similar resources. The Intermodal Surface Transportation Efficiency Act (ISTEA) of 1991 and the Transportation Equity Act for the 21st Century (TEA-21), enacted in June 1998, expanded the ability to pay for wetland banking. Typically, wetland mitigation banks are established to compensate for unavoidable wetland impacts, which occur on many highway projects. By consolidating efforts and improving site management, banking can result in reduced costs and the more rapid completion of the project.

TEA-21 also encouraged environmental restoration to address water pollution or environmental degradation caused or contributed by transportation facilities. Environmental restoration is a process of returning a habitat or ecosystem to a state as close as possible to its original condition and function.

In addition, TEA-21 increased the eligibility for funding to mitigate the effects of highway projects, including transportation enhancements, on natural habitats. Transportation enhancements include projects for bicycle and pedestrian facilities, scenic byways, scenic or historical sites/highway programs, historic preservation, control and removal of outdoor advertising, archaeological planning and research, and mitigation of water pollution from highway runoff.

ISTEA and TEA-21 recognize changes in wetland management regulations, procedures, and processes, and they include important new authorization for the use of federal transportation funds for wetland mitigation. The National Highway System and the Surface Transportation Program, which was created by ISTEA, allow for expenditures of federal-aid highway funds for efforts to conserve, restore, enhance, and create wetlands. Under both programs, contributions to mitigation efforts may take place concurrent with or in advance of project construction.

Landscape logs were added to the Coal Creek-Lafayette Bypass wetland mitigation project to enhance wildlife habitat and to provide a resting roost for migratory birds.

Over the short period of time that FHWA has been monitoring the performance of federal-aid highway programs in relation to wetlands gains, the outcome has been positive. However, it is too early to draw conclusions concerning the long-term mitigation success and the ecological effectiveness of these programs. Further research is needed on the successes and the performance of compensatory mitigation sites to achieve long-term strategic performance objectives.

FHWA is committed to preserving wetlands, and the agency is moving steadily toward its goal of achieving a 50-percent increase in wetlands acreage resulting from federal-aid highway projects from 1998 to 2008.

Kirstyn White was an intern in FHWA's Office of Natural Environment. She is a junior, majoring in civil and environmental engineering at Clarkson University in Potsdam, N.Y. She worked on FHWA's Water and Ecosystem Team while participating in the Washington Semester International Environment and Development Program at American University in Washington, D.C., during fall 2000.



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