- Briefing Room
U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
The Clean Water Act (Section 404(b)(1) Guidelines) requires that no discharge of fill material be permitted unless appropriate and practicable steps have been taken which will minimize potential adverse impacts of the discharge on the aquatic ecosystem. Mitigation is an action intended to reduce the effect of a specific activity. Mitigation includes: a) avoiding the impact altogether by not taking a certain action or parts of an action, b) minimizing impacts by limiting the degree or magnitude of the action and its implementation, c) rectifying the impact by repairing, rehabilitating, or restoring the affected environment, d) reducing or eliminating the impact over time by preservation and maintenance operations during the life of the action, and e) compensating for the impact by replacing or providing substitute resources or environments (40 CFR § 1508.20). This guidance identifies the procedure for developing compensatory mitigation for unavoidable impacts to aquatic resources (see glossary). It includes mitigation categories (c) and (e) outlined in the previous paragraph. Compensatory mitigation is the replacement of functions and values to the extent practical. As clarified in the "Memorandum of Agreement Between the Environmental Protection Agency and the Department of the Army Concerning the Determination of Mitigation Under the Clean Water Act Section 404(b)(1) Guidelines" (February 6, 1990), project sponsors must take a sequential approach to mitigation; first, avoid aquatic impacts, then minimize impacts (see Alternatives Analysis / Aquatic Resource Avoidance Guidance). Once the project has been evaluated under this process it will then be possible to explore other forms of mitigation.
Where avoidance and minimization of aquatic resource impacts are not practicable, the project sponsor will identify preliminary compensatory mitigation needs. Impact levels will be based upon information obtained following the Level of Data Needs / Threshold for Involvement Guidance. At the transportation planning stage mitigation banking can be evaluated following initial determination from Corps and EPA that conditions permitting banking are present, and where banking will provide for equivalent or higher quality replacement of functions and values. Mitigation banking for aquatic habitats is defined as the creation, restoration, or enhancement of wetland or other aquatic habitats and their functional values expressly for the purpose of providing compensatory mitigation in advance of proposed discharges into waters of the U.S. (see glossary) permitted under the section 404 regulatory program. Banks are created for an unknown number of future project impacting waters of the U.S. Mitigation banking may be appropriate for compensating cumulative impacts on aquatic resources identified at the transportation planning stage. Initial identification of mitigation bank sites should be coordinated with local resource planning efforts. The location of any mitigation bank site should augment or be compatible with regional and local planning efforts, such as watershed planning, natural community conservation planning (NCCP), special area management plans (SAMP), habitat conservation plans (HCP), multiple species management, and open space preserves.
At this phase, the project sponsor needs to describe proposed mitigation, including the expected functions and values anticipated to compensate for unavoidable impacts. Mitigation cost estimates must be incorporated in the various alternatives being considered. Programs using a common funding source may be able to develop, where indicated appropriate by Corps, EPA, and FWS, a mitigation bank for anticipated compensation commitments for several projects.
The project sponsor needs to develop a compensatory mitigation plan, including a feasibility study, conceptual mitigation plan, and final mitigation plan. A feasibility study of candidate mitigation site(s) will be completed prior to circulation of the draft EIS. The Corps will review candidate site(s) following their jurisdictional determination. Candidate mitigation site(s) will be identified in the conceptual mitigation plan and the draft EIS. Following issuance of the record of decision, the final mitigation plan will be developed and submitted to the Corps for approval. Throughout the development and implementation of a mitigation plan, a mitigation project management structure is needed to identify the responsible agency, the implementing agency, the monitoring agency, and timing of implementation in relation to the proposed project. The mitigation project management structure will:
The feasibility study is a preliminary investigation of candidate mitigation sites. The feasibility study information can be obtained by site visits, cursory investigations, record searches of existing databases, and referencing existing plans and land use documents. The purpose is to quickly determine if conditions exist on site that will support the mitigation activity being proposed.
The conceptual mitigation plan includes information about the specific mitigation which further elaborates upon the ability to successfully execute the mitigation. This plan also serves to identify in general terms the extent and nature of the mitigation and should include: § Habitat types and approximate hectares of impact § Plant communities and habitat to be replaced § Functions and values enhanced or created by the mitigation § Discussion of buffer areas and habitat linkages § General discussion of hydraulic design considerations § Listing of species to be used § Cost estimate § Mitigation success criteria § Monitoring criteria for evaluation of the mitigation The 404 application to the Corps will include the management structure, candidate sites, feasibility studies and a conceptual mitigation plan.
The final document needs to carry forward the information contained in the draft EIS. The feasibility study conducted during the selection process will determine suitability. The basis for selection will be the adequacy of the site to compensate for the functions and values impacted for the preferred alternative or each alternative in the draft EIS. The Corps will review the final candidate mitigation site(s) as part of its normal review at this stage. Before approval of the final environmental document, the Corps, EPA, and FWS must provide written preliminary agreement on the mitigation site(s).
The final mitigation plan and specifications must be approved by Corps before a permit will be issued. The final mitigation plans and specifications will be completed following the FONSI or record of decision.
Final Mitigation Plan
Several approaches have been formulated for restoring or creating wetlands. Each site has its own circumstances or conditions which dictate the approach or procedure to follow. Each Corps District has developed habitat mitigation and monitoring guidelines which outline the items desirable in a project mitigation plan. These documents should be considered as guidelines with the appropriate level of information and the timing of development dictated by the specific circumstances of the site and mitigation project.
Abell, D.L. 1989. Proceedings of the California Riparian Systems Conference: protection, management, and restoration for the 1990's; September 22-24, 1988; Davis, CA.
Gen. Tech. Rep. PSW-110. Berkeley, CA: Pacific Southwest Forest and Range Experiment Station, Forest Service, U.S. Department of Agriculture; 544p.
Gore, J.A. 1985. The Restoration of Rivers and Streams: Theories and Experience. Butterworth Publishers, Boston. 280p.
Hammer, D.A. 1989. Constructed Wetlands for Wastewater Treatment: Municipal, Industrial and Agricultural. Lewis Publishers, Boca Raton. 831p.
Hammer, D.A. 1992. Creating Freshwater Wetlands. Lewis Publishers, Boca Raton. 298p. "Memorandum of Agreement Between the Environmental Protection Agency and the Department of the Army Concerning the Determination of Mitigation Under the Clean Water Act Section 404(b)(1) Guidelines," February 6, 1990.
Memorandum of Agreement between California Department of Transportation, Federal Highway Administration, U.S. Army Corps of Engineers, U.S. Environmental Protection Agency, U.S. Fish and Wildlife Service, and the California Department of Fish and Game: "Early Mitigation Planning for Transportation Improvements in California," May 13, 1991.
Memorandum to the Field between the Environmental Protection Agency and the U.S. Army Corps of Engineers, dated August 23, 1993: "Establishment and Use of Wetland Mitigation Banks in the Clean Water Act Section 404 Regulatory Program."
This guidance addresses the interagency process and level of data needed during transportation planning, programming and development for only waters of the U.S. and associated sensitive species (see glossary). This guidance does not cover the many other sensitive environmental resources and issues (such as threatened and endangered species not associated with aquatic habitats, recreation land, cultural resources, socioeconomic concerns, and air quality) that must also be addressed at these stages as required by the pertinent laws and regulations.
All MPO's who find the transportation system or action likely to require a Corps individual section 404 permit should inform the applicable offices of the Federal and State agency MOU signatories.
The MPO and State DOT should consult with other potential sponsoring, regulatory, and resource agencies to determine whether impacts to aquatic resources are likely to be substantial. If so, more detailed studies should be conducted to evaluate potential impacts. This study may be included in a subarea or corridor study. These studies and/or any RTP's that may contain these studies should be submitted to the regulatory and resource agencies for their input before the document is finalized.
The State DOT's should determine on an annual basis which MPO's should meet directly with the resource and regulatory agencies to discuss the aquatic resource issues related to their RTP. The review of the Overall Work Program provides a venue to determine if the budget and work plans of MPO's consider the requirements of the NEPA-404 integration MOU.
MPO's should send a copy of the circulated draft RTP and any associated environmental documents to the appropriate signatory agency contacts as identified in Appendix A. The transmittal letter should indicate whether there are potential significant impacts to aquatic resources.
During the development of the draft RTP, the State DOT's will "review and comment on the adequacy of information and avoidance of sensitive resources presented in the RTP's and associated environmental analyses" and "request federal regulatory/resource agencies to review and comment on the RTP's and associated environmental analyses" (MOU, page 5).
The Corps, EPA, FWS and NMFS will "provide input to draft RTP's (relating to waters of the U.S. and to associated sensitive species)" and "review and comment on RTP's and associated environmental analyses within the public review period: purpose and need, alternative selection, mode, environmental impacts including cumulative impacts" (MOU, page 5).
During the development of the draft RTP, the State DOT's will "review and comment on the adequacy of information and avoidance of sensitive resources presented in the RTP's and associated environmental analyses" (MOU, page 5).
The State DOT may invite the regulatory and resource agencies to comment when it appears that an RTP will have unavoidable impacts to special aquatic sites. These agencies may then choose to become involved in estimating the extent of the resources at risk, and assessing the adequacy of the avoidance/minimization alternatives.
Data Needs The RTP and associated environmental documentation will contain sufficient information to assess potential impacts to aquatic resources.
The extent and quality of existing resources must be assessed to determine if avoidance alternatives are needed. To accomplish this, information sources that must be consulted at this stage are:
FWS National Wetlands Inventory (NWI) maps, Natural Diversity Data Base (NDDB) or other natural diversity databases (the State DOT's should assist the MPO's with obtaining and accessing NWI maps and the natural diversity databases), FWS Endangered Species office for associated sensitive species lists, maps, and/or Habitat Conservation Plans.
It is recommended that the MPO's also consult the following sources:
The project sponsor should consult the information sources required and recommended for the Transportation Planning stage, above, if not done so earlier.
As part of the project study report or project assessment, the project sponsor shall provide the regulatory and resource agencies the following:
A project description including purpose and need (see Purpose and Need Guidance.
Maps that show project alternatives, the aerial extent of and impacts to aquatic resources.
The "pre-scoping information" (see NEPA-404 Permit Concurrent Process) to be included in the project sponsor invitation letter to the regulatory and resource agencies is the information outlined in II.B.2, above and, in particular, should include a discussion of purpose and need (see Purpose and Need Guidance), criteria for selecting the range of alternatives, and the project alternatives to be evaluated in the draft EIS (see Alternatives Analysis / Aquatic Resource Avoidance Guidance). This information must be developed at this stage if not done so earlier.
The "pre-assessment of waters of the U.S." will consist of the mapping information required at the Programming stage, as outlined above.
The NOI should summarize the following information from the pre-scoping stage:
Purpose and Need (see Purpose and Need Guidance).
Potential Alternatives and their impacts to aquatic resources and other environmental resources (see Alternatives Analysis / Aquatic Resource Avoidance Guidance).
Potential Mitigation (see Compensatory Mitigation Guidance).
The project sponsor should refine the purpose and need and alternatives analysis as outlined in the Purpose and Need andAlternatives Analysis / Aquatic Resource Avoidance Guidances for the Project Development stage. The project sponsor shall incorporate any information obtained during the scoping process on waters of the U.S. and associated sensitive species.
The project sponsor shall include the following information on special aquatic sites and other waters of the U.S. in the draft EIS/EA/CE:
Adamus, P.R., E.J. Clairain, Jr., R.D. Smith, and R.E. Young. 1987. "Wetland Evaluation Technique (WET); Volume II: Methodology." Operational Draft Technical Report Y-87-, U.S. Army Engineer Waterways Experiment Station, Vicksburg, Mississippi. Brinson, M.M., et. al. "Developing an approach for assessing the functions of wetlands."
In (W.J. Mitsch and R.E. Turner, eds.) Wetlands of the World: Biogeochemistry, Ecological Engineering, Modeling and Management. Elsevier Publishers, Amsterdam.
California Department of Transportation. 1990. "Guidance for Consultants ¾ Procedures for Completing the Natural Environment Study and Related Biological Reports."
Caltrans Office of Environmental Analysis.
The Wetland Evaluation Technique II (WET II) is a methodology for assessing wetland functions and values. It was designed primarily for conducting initial, rapid assessments of wetlands. WET II with professional judgement is the current FHWA-recommended methodology for evaluating wetlands. Wetland assessments need to rely heavily on the wetland biologist's professional judgement and field experience.
A detailed assessment of project impacts on special aquatic sites and other waters as follows:
A detailed purpose and need statement (see Purpose and Need Guidance).
A draft Alternatives Analysis as described in the Alternatives Analysis / Aquatic Resource Avoidance Guidance (including both the "initial" and "refined" analyses).
A feasibility study of candidate mitigation sites (see Compensatory Mitigation Guidance).
Record of Decision/FONSI/CE