Environmental Guidance Documents

NEPA Process Guidance for Federal Aid Projects



Symbol that is used to denote “Section” as it relates to a section of a law or regulation


A reduction in sound levels

attainment area

Geographic area that meets or has pollutant levels below a given standard

categorical exclusion

A categorical exclusion document is prepared for a proposed action and is approved, by the federal agency overseeing the project for category of actions that have been deemed, by federal agencies, as not having significant effects on the environment.

critical habitat

Specific geographic area that is essential for the conservation of a threatened or endangered species.  It may require special management and protection.  It should be noted that critical habitat may include an area that is not currently inhabited by a species but that will be needed for its recovery.

de minimis

Impact to a Section 4(f) property that, after taking into account any measures to minimize harm (such as avoidance, minimization, mitigation or enhancement measures), results in either: 1) a Section 106 finding of no adverse effect or no historic properties affected on a historic property; or 2) a determination that the project would not adversely affect the activities, features, or attributes qualifying a park, recreation area, or refuge for protection under Section 4(f).

environmental assessment (EA)

A document that provides analysis for determining whether the proposed action will cause significant impacts. If it is determined that there will be no significant impacts as a result of the proposed action, a Finding of No Significant Impact (FONSI)  is issued and the EA fulfills the agency’s compliance with NEPA.  If it is determined that the proposed project will cause a significant impact, an Environmental Impact Statement (EIS) must be prepared.

environmental impact statement (EIS)

A document prepared to describe the effects for proposed activities on the natural and physical environment when significant impacts are anticipated. The “environment” considered in an EIS includes land, water, air, living organisms, and the cultural and socio-economic aspects. An "impact" is a change in consequence that results from an activity. Impacts can be positive or negative or both. An EIS describes impacts, as well as ways to mitigate (alleviate negative impacts) and monitor impacts.

environmental justice (EJ)

Executive Order 12898, Federal Actions to Address Environmental Justice (EJ) in Minority and Low-Income Populations (EO) focuses federal attention on the environmental and human health conditions in minority and low-income communities, enhances efforts to assure nondiscrimination in federal programs affecting human health and the environment, and promotes meaningful opportunities for access to public information and for public participation in matters relating to minority and low-income communities and their environment. The EO directs all federal departments and federal agencies to take the appropriate steps to identify and address any disproportionately high and adverse human health or environmental effects of federal programs, policies, and activities on minority and low-income populations.


A type of water feature such as a wetland, spring, stream, river, pond or lake that only exists for a short period following a precipitation  event. They are not the same as intermittent or seasonal water features which exist for longer periods, but not all year round.

federal nexus

When a project uses federal agency funds, requires federal agency authorization, or is part of a federal program, federal agency involvement is required.

Federal Register

Announces proposed changes to agency rules and has been in publication since March 14, 1936. It can be abbreviated as FR or Fed. Reg. The Federal Register is compiled by the Office of the Federal Register and is printed by the Government Printing Office. The final rules promulgated by a federal agency and published in the Federal Register are organized by topic or subject matter and codified in the Code of Federal Regulations (CFR), which is updated annually.  There are no copyright restrictions on the Federal Register: as a work of the U.S. government, it is in the public domain.   Citations from the Federal Register are [volume] FR [page number] ([date]), e.g., 23 FR 771.115 (2000-06-01).

finding of no significant impact (FONSI)

Presents the reasons why an action will not have a significant effect on the human or natural environment.  A FONSI is issued when environmental analysis documented in an EA and interagency review finds a project to have no significant impacts on the quality of the environment.

geotechnical (geotech)

Study of underground investigations that are performed by boring, sampling, and testing the soil strata to establish its compressibility, strength, and other characteristics likely to influence a construction project.

HAZMAT (hazardous materials)

Substances, such as flammable or poisonous materials, that would be a danger to life or to the environment if released without precautions.  Studies are conducted to identify hazardous materials, such as leaking underground storage tanks and/or asbestos. These studies vary in depth of investigation depending on the nature of the project, type of land uses, and the amount of ground disturbance.

maintenance area

Geographic area that was classified as a nonattainment area, but is now consistently meeting air quality standards. Maintenance areas have been re-designated by the US Environmental Protection Agency from "nonattainment" to "attainment with a maintenance plan”. These areas have demonstrated through monitoring and modeling to have sufficient controls in place to meet and maintain current air quality standards.  These areas also have contingency plans in place if air quality begins to decrease.

nonpoint source pollution

Generally results from land runoff, precipitation, atmospheric deposition, drainage, seepage or hydrologic modification. The term "nonpoint source" is defined to mean any source of water pollution that does not meet the legal definition of "point source" in section 502(14) of the Clean Water Act.

nonattainment area

An area where air pollution levels persistently exceed the National Ambient Air Quality Standards.

notice of intent (NOI)

Announces an agency’s decision to prepare an EA or EIS published in the Federal Register.  The NOI describes the proposed action, alternatives, scoping and the point of contact for the project. Scoping may begin after the NOI is published.

noxious weeds

The Noxious Weed Act of 1974 states:  any living stage, such as seeds and reproductive parts, of any parasitic or other plant of a kind, which is of foreign origin, is new to or not widely prevalent in the United States, and can directly or indirectly injure crops, other useful plants, livestock, or poultry or other interests of agriculture, including irrigation, or navigation, or the fish or wildlife resources of the United States or the public health.

point source pollution

Any obvious, confined and discrete conveyance, including but not limited to any pipe, ditch, channel, tunnel, conduit, well, discrete fissure, container, rolling stock, concentrated animal feeding operation, or vessel or other floating craft, from which pollutants are or may be discharged. This term does not include agricultural storm water discharges and return flows from irrigated agriculture.

record of decision (ROD)

Typically prepared after the Final Environmental Impact Statement, the ROD identifies alternatives considered and which ones are environmentally preferable.  The mitigation measures that were adopted are presented and the commitment to a monitoring and enforcement program is stated to insure implementation of mitigation measures.  The ROD is a public document.


Area of land that is directly influenced by water.  It is transitional between land and a water ecosystem usually having visible vegetative or physical characteristics. River sides, lake borders, and marshes are typical riparian areas.

scoping (project engineering/design)

Engineering/Design Process - further define project purpose and need; establish project objectives; identify design criteria; provide a preliminary identification of feasible alternatives; further define project scope, schedule, and budget; and make preliminary identification of federal agency involvement for NEPA.

scoping (NEPA)

An early and open process for determining the scope of issues to be addressed and for identifying the significant issues related to a proposed action.  Scoping sets the boundaries for analysis and helps to identify information sources.  Both agency and public input is included in the scoping process.

Section 4(f)

Section of the Department of Transportation Act 1966 that states the Federal Highway Administration and other department of transportation agencies cannot approve the use of land from publicly owned parks, recreational areas, wildlife and waterfowl refuges, or public and private historical sites unless there is no feasible and prudent alternative to the use of land, and the action includes all possible planning to minimize harm to the property resulting from use.

Section 6(f)

Section of the Land and Water Conservation Fund that states “No property acquired or developed with assistance under this section shall without approval of the Secretary [of the Interior] be converted to other than public outdoor recreation uses. 

Title VI

Part of the Civil Rights Act of 1964 which assures that individuals are not excluded from participation in, denied the benefit of, or subjected to discrimination based on race, color, national origin, age, sex and disability.


Under the Clean Water Act, the term wetlands means "those areas that are inundated or saturated by surface or groundwater at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs and similar areas."  Wetlands vary widely because of regional and local differences in soils, topography, climate, hydrology, water chemistry, vegetation, and other factors, including human disturbance.