Wetlands Mitigation Data Report for Federal-Aid Highway Projects
Fiscal Year 1998

Background

An indicator of meeting the FHWA Strategic Plan objective for protecting the natural environment is to ensure that mitigation on Federal-aid highway projects will result in a net increase of wetland acreage of at least 50% in ten years. Documenting agency performance toward achieving this indicator requires information from State Departments of Transportation and FHWA field offices that would allow a comparison of the area of wetlands unavoidably impacted to the area of wetlands provided through compensatory wetland mitigation efforts. The most direct and straight-forward way to gather the information is on an areal (acre) basis.

As a result, progress during Fiscal Years 1996, 1997, and now, 1998 has been measured for Federal-aid projects nationwide by comparing the total acres of wetland impacted by projects in the reporting State programs to the acres of wetland provided as compensatory mitigation. In FY 1998, the ratio of total acres impacted to acres mitigated indicates an increase in wetlands acreage of roughly 120% for areas impacted by Federal-aid projects. The current data indicate only nationwide acreage of impacts and mitigation installed for FY 1998. As this is a short period of time, few conclusions can be drawn concerning replacement of wetland functions and values, long-term mitigation success, ecological effectiveness, and other similar indicators which would be required for a complete assessment of a sustained net gain performance. We, therefore, recommend that information presented here for FY 1998 and the data reported for previous years be used with the caution that further and continuing assessment would be necessary to substantiate the achievement of our long range strategic performance objectives.

However, we believe the current data, in conjunction with similar data compiled for Fiscal Years 96 and 97, provides a valuable performance indicator of the Federal-aid highway program in achieving an immediate increase of wetland area, and is strongly indicative that a net gain of wetlands can be realized through the Federally funded highway program.

Results

On average, the FY 1998 figures indicate that Federal-aid highway projects provided 2.2 acres of compensatory wetland mitigation for each acre of impact. (Table, page 2) The results also indicate the magnitude of the highway program's contribution to overall nationwide wetland impacts and mitigation. Recent estimates of total wetland loss indicate that, between 1982 and 1992, approximately 160,000 acres of wetlands per year were still being converted to other land cover types by all sources of impacts. During that period, approximately 75,000 acres of wetlands per year were being restored or created. Subsequent to 1992, an additional 68,000 acres per year of wetlands have been restored or established as the result of the Wetlands Reserve and other new wetland conservation programs. These figures are based on our interpretation of information available from the U.S. Fish and Wildlife Service National Wetlands Inventory and U.S. Department of Agriculture (USDA) National Resource Inventory.

Using the FY 1998 data, we estimate that impacts from the Federal-aid highway program would account for approximately 1326 acres per year losses and 2905 acres per year mitigation (from individual Section 404 permits for all 50 states, Puerto Rico and the District of Columbia), representing a relatively small percentage of the total, national wetland loss/gain rate. The estimates for all States, Puerto Rico, and the District were made using the data from the 46 States reporting divided by the fraction of States reporting: 46/52= 0.88.

The following table provides the acreage figures provided by Field Offices in response to a memorandum sent to the field requesting wetland loss/gain data. Primarily, these data are from projects involving Section 404 individual permits, and do not include projects built under Nationwide or other general permits. The data are not intended to provide a complete record of wetland impacts due to Federally funded highway projects, but a measure of program performance against a "net gain of wetlands" criteria.

Summary

The reports submitted indicate that our compensatory mitigation ratio is approximately 2.2:1, representing about 2% of the estimated total nationwide wetland replacement rate, most of which comes from restoration of agricultural lands. This ratio is comparable for wetlands impact: mitigation data collected in FY 1996 and FY 1997, which were 2.3:1 and 2.6:1, respectively.

The mitigation ratio indicated by these data are a strong indication that the project eligibility and funding provisions for wetland mitigation in the Intermodal Surface Transportation Efficiency Act of 1991 (ISTEA) have been effective in enhancing the natural environment. We feel that those provisions, now continued in TEA-21, are critical to maintaining this trend into the future, and will be effective in accomplishing the Nation's environmental goals under the Vice-President's Clean Water Action Plan initiatives and the Administration's National Wetlands Plan. We also believe these data reflect opportunities available for increased flexibility in mitigating wetlands impacts through other wetland conservation programs which are eligible for TEA-21 funds. This could yield further cost efficiencies and ecological benefits in mitigating the wetland impacts of highway projects.