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NEPA 404 MOU Guidance (Part 2)



For major Federal actions significantly affecting the human environment, the National Environmental Policy Act (NEPA) requires rigorously exploring and objectively evaluating "all reasonable alternatives" that meet the project purpose. NEPA requires a discussion of mitigation for adverse environmental impacts of alternatives, where mitigation is defined to include avoidance and minimization of impacts as well as restoration and creation of habitats. Section 404 of the Clean Water Act, which permits discharges of fill into the waters of the United States (see glossary), also requires consideration of practicable alternatives to avoid and minimize adverse environmental impacts, and further requires that these measures be exhausted before turning to restoration and creation of habitats.

Alternative Selection

A reasonable range of options must be considered in the evaluation of alternatives. Alternatives can be eliminated, prior to detailed analysis, if they are not "reasonable" (under NEPA) or if they are not "practicable" (under 404). When evaluating alternatives, transportation agencies should give equal consideration to section 404 and Department of Transportation Act section 4(f) concerns, and select the alternative that would cause the least overall environmental harm.

Transportation Planning Stage

Avoidance of large or valuable aquatic resources (see glossary) is best addressed at the systems planning stage. System or regional planning requires Metropolitan Planning Organizations (MPO's) to prepare Regional Transportation Plans (RTP's). The RTP and associated documentation (such as the environmental impact report in California), and corridor and subarea studies are appropriate vehicles in which to assess system design alternatives and their environmental effects. System design encompasses: system management strategies and the mode, general location, and capacity for the proposed regional transportation facilities; the purpose and need; the preliminary budget; and the design concept and scope. System design decisions related to the alternatives will be documented to support later project decisions. System design decisions, including design concept and scope, may be revisited if significant new information is discovered. If the above documents are sufficiently detailed to address the information requirements of NEPA and section 404, and if the system planning decisions are responsive to the regulatory requirements of NEPA and 404, it is expected that the reviewing agencies will indicate their concurrence with these decisions.

Project Programming Stage

Prior to programming, the project sponsor must develop adequate information on the environmental resources to analyze each alternative and to develop project cost estimates for each alternative which includes the cost of avoiding or minimizing and compensating for the impacts to the environmental resources. The project sponsor should document earlier analyses, continue coordination with the regulatory and resource agencies (or initiate coordination if this project was in an RTP before the MOU was signed), identify potentially impacted aquatic resources, and develop an alternatives analysis adequate to identify funding needed for avoidance and/or mitigation. If adequately prepared, this should result in EPA and Corps preliminary agreement on the alternatives to be analyzed in the project development stage, including avoidance alternatives and conceptual mitigation.

Project Development Stage

If the agencies have not already agreed with decisions made at the planning and programming level, then the systems design and budget issues will need to be reviewed at this stage and concurrence obtained. More detailed analyses may be needed to evaluate location alternatives than were provided at earlier stages; these analyses should also consider design alternatives. To achieve concurrence from EPA and the Corps prior to the project decision, the project sponsors must follow the NEPA-404 Permit Concurrent Process (MOU Appendix A).


The goal of this paper is to provide guidance on conducting alternatives analyses to meet the requirements of both NEPA and section 404 of the Clean Water Act. This guidance is provided for project sponsors and the planning, regulatory, and resource agencies. It is to be used in the transportation planning, project programming, and project development stages. Although potential alternatives are evaluated at each of these three stages, it is not usually until the last stage (which includes NEPA and 404 permitting) that substantive determinations regarding the adequacy of alternatives development and analysis occur. This paper provides guidance on how to consider aquatic resource issues throughout all three stages of transportation planning. Also included for each stage is a summary of existing guidance, and examples to illustrate how the regulatory agencies view practicability. The basic requirements of NEPA and section 404 of the Clean Water Act are described below.

National Environmental Policy Act

NEPA regulations require the preparation of an environmental impact statement (EIS) for major Federal actions which significantly affect the human environment. (An environmental assessment may need to be prepared to determine whether an impact is significant.) NEPA regulations (40 CFR Parts 1500-1508) require that an EIS rigorously explore and objectively evaluate all reasonable alternatives (See section III.A. below). NEPA requires that mitigation measures be discussed as a part of each alternative or as a separate alternative applicable to the other alternatives. Mitigation pursuant to NEPA includes avoiding, minimizing, rectifying, reducing or eliminating over time, or compensating for the impact(s) (40 CFR § 1508.20).

Section 404 of the Clean Water Act

Alternatives Analysis

The Guidelines promulgated under section 404 of the Clean Water Act specify that a permit can be issued for a discharge of dredged or fill material to waters of the United States only if the discharge is determined to be the least environmentally damaging practicable alternative (LEDPA) (40 CFR § 230.10(a); section 404 sets out other requirements as well; see section II.B.2. below). When a proposed project requires an individual permit for filling waters of the United States, an analysis of alternatives must be carried out. For this analysis, the LEDPA generally is the practicable alternative that either avoids waters of the U.S. or impacts the smallest area of waters. For non-water dependent projects (essentially all surface transportation projects) that require filling of wetlands or other special aquatic sites (see glossary), the Guidelines also presume that there are upland alternatives available and that these upland sites are less environmentally damaging. The burden to prove otherwise is on the project sponsor. In particular, the "no project" alternative, and projects that avoid or minimize fill must be carefully analyzed. An alternative with fewer impacts to aquatic resources than the preferred alternative may be eliminated by demonstrating that it has other overriding severe environmental impacts.

Other Requirements of Section 404

The Section 404(b)(1) Guidelines state at 40 CFR § 230.10: Although all requirements in § 230.10 (including the alternatives analysis) must be met, the compliance evaluation procedures will vary to reflect the seriousness of the potential for adverse impacts on the aquatic ecosystems posed by specific dredged or fill material discharge activities.

In 40 CFR §§ 230.10(b)-(d), the Guidelines further state in part that: (b) No discharge of dredged or fill material shall be permitted if it: (1) Causes or contributes .…to violations of any applicable State water quality standard;… (3) Jeopardizes the continued existence of species listed as endangered or threatened under the Endangered Species Act of 1973, as amended, or results in likelihood of the destruction or adverse modification of a habitat which is determined by the Secretary of Interior or Commerce, as appropriate, to be a critical habitat under the Endangered Species Act of 1973, as amended. If an exemption has been granted by the Endangered Species Committee, the terms of such exemption shall apply in lieu of this subparagraph; … (c)… no discharge of dredged or fill material shall be permitted which will cause or contribute to significant degradation of the waters of the United States…. (d) …no discharge of dredged or fill material shall be permitted unless appropriate and practicable steps have been taken which will minimize potential adverse impacts of the discharge on the aquatic ecosystem….

Comparison of NEPA and Section 404

The analysis requirements of NEPA and 404 as regards avoidance are slightly different but fully compatible. A 1990 Memorandum of Agreement between EPA and the Corps (reference listed in section VI.A. below) recognizes the value of each mitigation component defined under NEPA, and in addition ranks them to ensure that avoidance of impacts occurs first, before efforts to restore or create compensatory habitats. The impact analysis associated with alternatives should be formatted to reflect this priority. Because a section 404 permit can only be issued for the LEDPA, section 404 compliance usually requires a more detailed and specific analysis of the aquatic impacts of each alternative than NEPA. NEPA documents should provide enough information on alternatives to determine if selection of the preferred alternative complies with the 404(b)(1) Guidelines.


Criteria for Identifying Reasonable Alternatives

The evaluation of alternatives must consider a reasonable range of options that could fulfill the project sponsor's purpose and need. Reasonable alternatives are those that "are practical or feasible from the technical and economic standpoint and using common sense, rather than simply desirable from the standpoint of the applicant" (Council on Environmental Quality, 1981; see VI.A below for reference). The range of alternatives to be considered should include at minimum: 1) alternative ways of meeting the project sponsor's purpose and need at the same location, 2) alternative locations, and 3) the "no action" alternative. The evaluation of the environmental impacts of all reasonable alternatives must be presented in comparative form to provide a clear basis for choosing among options. If alternatives are eliminated from further analysis, either the environmental document or a separate alternatives analysis must discuss the reasons for elimination.

Criteria for Identifying Practicable Alternatives

For transportation projects, generally, an alternative is practicable if it: 1) meets the purpose and need; 2) is available and capable of being done (i.e., it can be accomplished within the financial resources that could reasonably be made available, and it is feasible from the standpoint of technology and logistics); and 3) will not create other unacceptable impacts such as severe operation or safety problems, or serious socioeconomic or environmental impacts. Alternatives can be eliminated at any stage if they are not "reasonable" (NEPA), or if they are not "practicable" (404). However, the reasons for eliminating an alternative from detailed analysis need to be documented and discussed in the document prepared at that stage. Based on this information, the project sponsor must get EPA and the Corps of Engineers concurrence that there are no other less-environmentally damaging practicable alternatives than those identified.

Consideration of Other Environmental Impacts

The Clean Water Act 404(b)(1) Guidelines require that the practicable alternative that would involve the least adverse impact to aquatic resources be chosen unless this alternative would have other significant environmental consequences (40 CFR § 230.10(a)). Similarly, section 4(f) of the Department of Transportation Act allows the transportation agency to reject an alternative as not feasible and prudent if "unacceptable adverse… environmental impacts" would result (FHWA, November 15, 1989). Thus, both regulations allow the potential for other significant environmental impacts to override either protection of aquatic resources (in the case of section 404), or preservation of public park and recreation lands, wildlife refuges and historic sites (in the case of section 4(f)). Sometimes the only practicable alternatives that are available would either fill aquatic resources or impact section 4(f) resources. Thus, in some instances, it may be necessary to accept impacts to one resource in order to avoid or minimize impacts on another resource. The alternatives analysis should reflect the equal consideration of section 4(f) and section 404 concerns when evaluating alternatives. However, this equal consideration may change depending on specific project and community circumstances, and the magnitude of the impacts. The alternative that would result in the least overall environmental harm as determined through discussions with regulatory and resource agencies needs to be selected. An important distinction to keep in mind when evaluating harm to non-aquatic (i.e., 4(f)) resources versus harm to waters of the U.S., is that, for the former, the alternatives selection process evaluates reasonable and prudent alternatives based on the "net harm" (after mitigation) of the alternative to 4(f) properties or other environmental resources. In contrast, for almost all section 404 alternatives analyses, the evaluation of practicable alternatives must consider the impact to waters of the U.S. that would result from the alternative beforecompensatory mitigation (see 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) for exceptions to this sequence). This MOA expressly states that "compensatory mitigation may not be used as a method to reduce environmental impacts in the evaluation of the least environmentally damaging practicable alternative." Therefore, if an alternative exists where the impacts to non-aquatic resources can be practicably mitigated, this alternative should generally be selected over one that would fill waters of the U.S.


Transportation planning requires Metropolitan Planning Organizations (MPO's) to prepare Regional Transportation Plans (RTP's) and Transportation Improvement Programs, and State Departments of Transportation (DOT's) to adopt a State Transportation Improvement Program.

Existing Guidance

There is no specific, formal guidance on section 404 alternatives analysis for this stage of planning; however, the following documents serve as general guidance: Intermodal Surface Transportation Efficiency Act of 1991. Pub. L. 102-240, December 18, 1991, 105 STAT. 1914. Federal Highway Administration and Federal Transit Administration. Planning Assistance and Standards. 23 CFR Part 450 (FHWA); 49 CFR Part 613 (FTA).

Early Coordination

The MPO's that have formally agreed to follow the NEPA-404 integration process should request that the Corps of Engineers, Environmental Protection Agency (EPA), Fish and Wildlife Service, and National Marine Fisheries Service review and comment on RTP's and associated environmental analyses as specified in the MOU under Transportation Plan Stage (MOU pages 4-5). SeeLevel of Data Needs / Threshold for Involvement Guidance section II.A. for details regarding agency involvement and information transmittal to the regulatory and resource agencies at the transportation planning stage.

Resource Identification

To meet the intent of section 404, it will be necessary for the MPO's to collect and analyze data on aquatic resources and listed and candidate species when preparing the RTP's. The MPO's should follow the Level of Data Needs / Threshold for Involvement Guidance specified for the planning stage. The MPO's may find it appropriate to develop, or request the project sponsors to develop, corridor or subarea studies focusing on system alternatives and environmental effects. The findings of these studies would be considered as the MPO's adopt the RTP.

Initial Selection of Alternatives

Development of Alternatives

Once the basic project purpose has been agreed upon according to the Purpose and Need Guidance, all reasonable alternatives that meet the basic purpose should be identified, and objectively compared. Alternatives analyses in the RTP can arise in two ways:
from system alternatives considered in the RTP environmental analysis. These include: facilities, demand management, systems management and land use.
from alternatives considered in corridor and subarea studies. These include modal choice, general alignment, and the development of the project concept and scope used in the emissions analysis. Impacts to wetlands and other special aquatic sites can be most effectively avoided during Transportation Planning. Any reasonable actions or alignments which avoid adverse impacts to waters of the U.S. and associated sensitive species (see glossary) should be rigorously examined. If it is not possible to entirely avoid rivers, streams, and other linear waters of the U.S., crossings should be located to minimize impacts to aquatic resources. This could include such actions as shifting the alignment to reduce the footprint of the transportation facility on the aquatic resource.

Criteria for Identifying Practicable Alternatives

MPO's can eliminate from consideration project alternatives that are not practicable if they carefully document their reasons. The following practicability constraints may be used to carry out the initial selection of alternatives:

  1. Not meeting the project purpose and need (formulated according to Purpose and Need Guidance),
  2. Excessive cost of construction (including all mitigation),
  3. Severe operational or safety problems,
  4. Unacceptable adverse social, economic or environmental impacts,
  5. Serious community disruption,
  6. Unsuitable demographics (for mass transportation modes), and
  7. Logistical and technical constraints The transportation agency must provide detailed documentation to demonstrate that rejected less-damaging alternatives considered are not practicable. Refer to section III.B. of this guidance paper.


The following example illustrates the alternative selection process at the planning stage. An MPO has identified a need to reduce congestion. The objective is to achieve/maintain at least "satisfactory" operating conditions (level of service "D") and the resource and regulatory agencies have concurred with objective. The MPO is only able to reasonably identify approximately $300 million with which to achieve this objective. Studies indicate that unless action is taken, operating conditions will deteriorate to "poor" (level of service "F"). The three alternatives identified by the MPO are described in the following chart.


Alt. A Alt. B Alt. C
Alternative No
Highway Emphasis Transit
Cost none $200
Home/Business Displacement
none low
none 40+ hectares
(~100+ Acres), including vernal pools
< 2 hectares (~5 acres) approx.
8 hectares
(~20 acres),
no vernalpools
Associated Sensitive
none three, (two
none one

In this example, the no-build alternative is rejected as not being practicable because the purpose of maintaining at least "satisfactory" operating conditions is not met. Alternative B is also rejected as not practicable due to excessive cost. While Alternative B achieves the purpose, and would involve the least impact of all the alternatives to aquatic resources, its cost greatly exceeds the reasonably expected funds. Alternative B may also be considered not practicable due to unacceptable socioeconomic impacts. The displacement of 200 homes/businesses with Alternative B, as opposed to 30 or 75 for Alternatives A and C respectively, would likely be considered unacceptable. Only Alternatives A and C are identified as practicable. At this point the MPO must determine if there is a practicable alternative that avoids impacts to aquatic resources. If so, it must be selected, so long as it does not result in other significant adverse environmental consequences. In this case, it was found that there was not a practicable avoidance alternative, so the practicable alternative that would cause the least impact to aquatic resources was selected. Alternative C was chosen because it would destroy around 32 fewer hectares (~80 acres) of aquatic resources than A, affect only one instead of three sensitive species (two of which are endangered), and not impact vernal pools, a wetlands habitat type that is very difficult to replace.


This stage identifies the budgets for project delivery. Efforts should be to set budgets which maximize flexibility when identifying reasonable alternatives. For projects potentially impacting waters of the U.S. and associated sensitive species, the project sponsors must identify the full range of reasonable alternatives (including a focused evaluation of avoidance alternatives), their costs (including mitigation), and general environmental implications.

Existing Guidance

Army Corps of Engineers. General Regulatory Policies.33 CFR Part 320.
Army Corps of Engineers. Nationwide Permit Program. 33 CFR Part 330.
California Department of Transportation. "Guidelines for the Preparation of Project Study Reports." September 12, 1991.
Environmental Protection Agency. Guidelines for Specification of Disposal Sites for Dredged or Fill Material.
40 CFR Part 230. Federal Highway Administration. Timing of Administrative Actions. 23 CFR § 771.113.

Early Coordination

The transportation agencies should consult with appropriate resource and regulatory agencies (i.e., the Corps, EPA, Fish and Wildlife Service, National Marine Fisheries Service, state water quality agency, state fish and game agency, and federal land management agencies, such as the Forest Service or Bureau of Land Management) early in the programming stage. This may include inviting the agency representatives to participate on the Technical Advisory Team. Field visits to the project area by project sponsor staff and resource agency personnel are invaluable for identifying resources of particular importance and potential project alternatives. Resource agencies should become involved in refining project-level alternatives and the selection criteria at this stage.

Resource Identification

The actual programming documents do not include environmental documentation. Rather, the related pre-scoping information (e.g., project assessments and project study reports) will address the potential impacts to these resources (see the Level of Data Needs / Threshold for Involvement Guidance).

Initial Selection of Project-Level Alternatives

This step should be carried out using the selection criteria and process outlined above under IV.D., if it has not been documented at the planning stage. Resource and regulatory agencies may disagree with the transportation agencies on what constitutes "excessive," "severe," "unacceptable," or "serious" in determining practicability (see list of selection criteria, IV.D.2.). Thus, for projects that will have a major adverse effect on aquatic resources, transportation agencies must work closely with the resource and regulatory agencies to get agreement on the magnitude of constraints needed to render alternatives impracticable.
A transportation agency is proposing to program a project described by the local MPO's long range plan. The plan identified the project for the purpose of reducing future congestion to at least "satisfactory" (level of service "D" operating conditions. The transportation and programming agencies are only able to reasonably identify approximately $90 million to use for this purpose. Three project alternatives have been identified by the transportation agency, and are described in the following chart.


Alternative C1 C2 C3
Congestion (Level of Service) fair
Cost $82
Home/BusinessDisplacements 19 10 10
Wetlands (Special Aquatic Site) Impacts 4 hectares
(~10 acres)
10 hectares
(~25 acres)
2 hectares
(~5 acres)
Endangered Species Impacted none one none

At the programming stage, the intent of the project sponsor should be to identify the full range of practicable avoidance or minimization alternatives, all of which should be formally considered at the project development stage. In this example, all the alternatives are within the range of expected funds and meet the project purpose. However, Alternative C2 would impact the greatest amount of wetlands and adversely affect an endangered species. Other practicable alternatives (C1 and C3) exist that avoid impacts to these resources to a greater extent. Therefore, Alternative C2 is rejected.

Documentation of Earlier Analyses

For most mode and location (alignment) alternatives, the initial selection alternatives analysis probably occurred at the transportation planning stage. If so, the transportation agency must either:
Document these earlier decisions as described above under IV.D., and discuss how they meet the selection criteria listed at IV.D.2., or
Provide evidence that the regulatory and resource agencies already concurred at the planning stage. For example, if one mode would be least damaging to aquatic resources but another mode was chosen during planning, the project sponsor should discuss in detail why the first mode is not practicable.


The discussion below addresses how to satisfy the requirements of the section 404 alternatives analysis in the context of a NEPA document.

Existing Guidance

The following list includes guidance on section 404, NEPA, and section 4(f) of the Department of Transportation Act. A few of the entries are annotated to clarify how they pertain to section 404 analyses for transportation projects.

California Department of Transportation. December 27, 1990. "Project Alternative Assessment Process."

California Department of Transportation. June 7, 1991. "Mandatory Design Exception Procedures/Fact Sheet Outline." Division of State and Local Project Development, Office of Project Planning & Design.

Council on Environmental Quality. November 29, 1978. Regulations For Implementing the Procedural Provisions of the National Environmental Policy Act. 40 CFR Parts 1500-1508.

Council on Environmental Quality. March 16, 1981. "Questions and Answers About the NEPA Regulations."

Environmental Protection Agency. December 24, 1980. Guidelines for Specification of Disposal Sites for Dredged or Fill Material. 40 CFR Part 230.

Environmental Protection Agency and U.S. Army Corps of Engineers. February 6, 1990. "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."

Federal Highway Administration. October 5, 1987. "Section 4(f) Policy Paper." Director, Office of Environmental Policy, Washington D.C.

Federal Highway Administration. October 30, 1987. "Guidance for Preparing and Processing Environmental and Section 4(f) Documents." Director, Office of Environmental Policy, Washington D.C. (Guidance to FHWA field offices and project applicants on the preparation and processing of environmental and section 4(f) documents. Provides a good discussion of how alternatives should generally be developed for NEPA (EIS) purposes (Attachment pages 14-17). Also describes procedures that should be followed when wetland impacts will occur, and briefly states that the draft EIS should "evaluate alternatives which would avoid these wetlands" (Attachment page 27). However, it focuses on determining the impact to wetlands and demonstrating compliance with Executive Order 11990, not section 404, e.g., it lays out a procedure for a "Wetland Only Practicable Alternative Finding" to satisfy the Executive Order.)

Federal Highway Administration. November 15, 1989. "Alternatives Selection Process for Projects Involving Section 4(f) of the DOT Act." Director, Office of Environmental Policy, Washington D.C.

Yocom, T.G., R.A. Leidy, and C.A. Morris. 1989. "Wetlands Protection Through Impact Avoidance: A Discussion of the 404(b)(1) Alternatives Analysis." Wetlands. Vol 9, No. 2, pages 283-297. (Guidance for preparing alternatives analyses. Focuses on residential, industrial, and commercial projects.)

Continued Interagency Coordination

It is critical for transportation agencies to coordinate with the resource and regulatory agencies throughout all of the transportation stages. If agencies have not been approached at earlier stages, contact with the resource and regulatory agencies (see list under IV.B.) at the project development stage will help determine the depth of the alternatives studies needed based on project scale and impact. As NEPA documentation is developed, the transportation agency sponsor should obtain interagency concurrence on the direction of the alternatives analysis. During the NEPA stage the project sponsor should:

Follow the steps outlined in the NEPA-404 Permit Concurrent Process for EIS's (MOU Appendix A) and NEPA-404 Permit Concurrent Process for EA's/CE's (MOU Appendix B). These processes require interagency concurrence on purpose and need, and alternative selection criteria and process at various milestones.

Describe the results of this and any other coordination with the agencies in the Alternatives Analysis Report (see below).

Preparing the Alternatives Analysis

For projects requiring alternatives analyses, both draft and final versions should be prepared in order to facilitate interagency input and concurrence. If a formal report is deemed unnecessary based on agency input, the project sponsor should determine from the agencies which elements of the procedure below need to be informally transmitted. The components of each report are described below. The 404 Alternatives Analysis should be presented in a separate section of the EA/FONSI or EIS. However, if the outlined information is adequately discussed elsewhere in the document, these discussions can be referenced and summarized in the 404 alternatives analysis.
Draft Alternatives Analysis (to be included in the Draft NEPA document: see the NEPA-404 Permit Concurrent Process in MOU Appendix A)

  1. Proposed Action Describe the proposed action and explain the project purpose (see Purpose and Need Guidance).
  2. Resource Identification Follow the Level of Data Needs / Threshold for Involvement Guidance.
  3. Documentation of Alternatives Considered But Rejected During the Initial Analysis For most mode and location (alignment) alternatives, the initial selection of alternatives probably occurred at the transportation planning stage. If so, the transportation agency must either:

document these earlier decisions as described above at IV.D. and discuss how they meet the selection criteria listed at IV.D.2., or
provide evidence that the regulatory and resource agencies already concurred at the planning or programming stage.

  1. Impacts of Each Alternative The full range and scope of practicable alternatives need to be presented in comparative form, thus sharply defining the issues and providing a clear basis of choice among options. The impacts on the aquatic resources and associated sensitive species should be discussed for each alternative, such as the amount to be lost, functions and values affected, and indirect impacts (e.g., growth inducement) and cumulative impacts to aquatic resources. Where several alternatives would affect aquatic resources, a summary table comparing the various impacts of each alternative should be prepared. For projects that would result in a significant impact to wetlands or sensitive species, the project sponsor will provide more documentation on the impracticability of wetlands minimization or avoidance alternatives than would normally be needed for the purposes of NEPA. Project sponsors will justify in detail how the cost, performance, socioeconomic impacts or other factors make the minimization or avoidance alternative impracticable. Project sponsors should also avoid using ambiguous terms such as "slight," "insignificant," "adverse," or "substantial" in the NEPA document when discussing environmental impacts, or project cost or performance. For example, in a draft EIS for a route extension, a less environmentally damaging alternative was eliminated partly because traffic impacts were "unacceptable" to a local city with no further discussion of what this term meant. Existing levels of service in another draft EIS were described simply as "unacceptable" or "adverse" to justify the construction of a new roadway. If such terms are used, they must be quantified with traffic data and modelling assumptions.
  2. Example The project sponsor has identified two practicable alternatives (see table below) for analysis in the draft EIS.


Alternative C1 C3
(Level of Service)
Cost $82 million $90 million
19 10
Wetlands (Special Aquatic
Site) Impacts
4 hectares
(~10 acres)
2 hectares
(~5 acres)
Hazardous Waste Dump

(~1970 feet)
600 meters of frontage

It has been discovered that the construction of Alternative C3 would extensively disturb a hazardous waste dump, and seriously harm the underlying aquifer. Thus, even though it would fill less wetlands, Alternative C3 is the more environmentally damaging of the two alternatives. Alternative C1 is therefore the least environmentally damaging practicable alternative, and is designated as the preferred alternative in the final EIS.

  1. Minimization of Impacts Later analyses may consider location alternatives in more detail than the initial analysis and should also consider design variations. At this stage, enough detail on the project is known to make adjustments to avoid wetlands and associated sensitive species. In some cases, temporal measures (e.g., no construction during the breeding season) may avoid or minimize impacts to associated sensitive species. Transportation agencies should consider, individually or in combination, design variations such as:
    1. Minor alignment shifts,
    2. Retaining structures,
    3. Bridging,
    4. Reduced cut and fill activity,
    5. Changes in profile,
    6. Changes in lane or median width,
    7. Variable slopes (to bring the toe of slope out of sensitive areas)
    8. Specific construction methods
  2. Final Alternatives Analysis (To be included in the final NEPA document; see the NEPA-404 Permit Concurrent Process in MOU Appendix A) The final 404 Alternatives Analysis should:
    1. Summarize the information from the draft Alternatives Analysis, and
    2. Clearly demonstrate that alternatives that would avoid aquatic resources to a greater extent than the preferred alternative are not practicable.
      1. If a practicable alternative that completely avoids aquatic resources exists, it must be selected unless that alternative has other significant adverse environmental consequences.
      2. If all the alternatives would result in some aquatic resource loss, the practicable alternative with least damage to aquatic resources must be selected unless that alternative has other significant adverse environmental consequences. The impacts to aquatic resources for each alternative must be evaluated before compensatory mitigation for this comparison (refer to section III.C. above).

  3. Record of Decision (for EIS's only) A record of decision must identify all alternatives considered and specify the alternative or alternatives which were considered to be environmentally preferable. The record of decision must state whether all practicable means to avoid or minimize environmental harm from the alternative have been adopted, and if not, why they were not.

Corps Approval of Alternatives Analysis The Corps of Engineers through its permit process will determine compliance of the alternatives analysis with the Section 404(b)(1) Guidelines and the public interest.

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