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Environmental Resources Information

What environmental resources must be considered under NEPA?

The NEPA document should focus on those environmental resources that have been identified as significant based on the scoping process. The level of detail for each resource should be in proportion to the significance of the impact, and the potential it has to affect the decisionmaking process for alternative selection.

Air Quality
Public transit projects proposed for federal funding must meet the requirements of the Clean Air Act,  in addition to NEPA.The purpose of the Clean Air Act is to protect and enhance air quality to promote public health and welfare of the nation and to accomplish this, the Act addresses criteria air pollutants that are regulated through the National Ambient Air Quality Standards (NAAQS). Learn more

Biological Resources
The effects of a proposed project on wildlife and vegetation, including critically rare animal and plant species and their habitats, must be considered as part of the NEPA process. The primary legal mandates that protect fish and wildlife species include the Endangered Species Act of 1973, Migratory Bird Treaty Act, Magnuson-Stevens Fishery Conservation and Management Act, and the Marine Mammal Protection Act of 1972. In addition, Section 4(f) of the Department of Transportation Act provides protection for wildlife and waterfowl refuges. Learn more

Energy Conservation
NEPA requires that environmental considerations such as impacts related to energy resources are given due weight in project decisionmaking. Energy may be addressed in a section describing energy and fuel consumption, and conservation potential.

Geology and Soils
Environmental impact assessment for transit projects requires a discussion of the geologic and soil conditions (including hazard areas) in the vicinity of the project area, detailing potential significant adverse impacts of the project alternatives on these conditions. Impacts include construction and operational impacts of the project alternatives on geologic and soil conditions, impacts of identified geologic hazards on the project alternatives, and indirect and cumulative impacts from both.

Hazardous Materials and Brownfields
The term “hazardous materials” is an all-inclusive term for materials that are regulated as a solid waste, hazardous waste, and other wastes contaminated with hazardous materials, radioactive materials, petroleum fuels, toxic substances, and pollutants. The discovery of hazardous materials within a proposed project area may have an adverse impact on timely completion of the project. Therefore, an assessment of potential areas of contamination should be conducted as early in the project development process as possible, and the initial findings presented in the draft environmental document (i.e., EA, Draft EIS). Learn more

Historic Resources
Historic, archeological, and cultural resources are protected under Section 106 of the National Historic Preservation Act of 1966 and Section 4(f) of the U.S. Department of Transportation Act.

Noise and Vibration
Noise and vibration assessments are key elements of the environmental impact assessment process for public transit projects. Experience has shown that noise and vibration are among the major concerns to the surrounding community for a proposed transit project.  FTA has guidance on how to assess noise and vibration impacts of proposed public transit projects (Transit Noise and Vibration Impact Assessment). This guidance is used by grant applicants seeking funding from FTA to evaluate these impacts during the environmental review process. All types of bus and rail projects are covered. The guidance contains procedures for assessing impacts at different stages of project development, from early planning before mode and alignment have been selected through preliminary engineering and final design. The focus is on noise and vibration impacts during operations, but construction impacts are also covered. The guidance describes a range of measures for controlling excessive noise and vibration.

Section 4(f) of the Department of Transportation Act
The U.S. Department of Transportation (USDOT) Act of 1966 included a special provision – Section 4(f) – that prohibits USDOT agencies, including FTA, from using land from publicly owned parks, recreation areas (including recreational trails), wildlife and water fowl refuges, or land from public and private historic properties.  Use may only be permitted if there is no feasible and prudent alternative to that use, and the action includes all possible planning to minimize harm to the property resulting from such a use. Learn more

Social Resources and Economic Impacts
Transit projects frequently have social and economic impacts,and may influence the character and nature of communities. These impacts should be addressed in environmental documents, as appropriate, and generally fall into the following categories: land acquisition (business, residential), community impacts, land use and development, economic impacts, and safety/security. A discussion of impacts to these resources can be found here.

Transportation Impacts
By definition, any proposed transit project will potentially influence elements of the local transportation system, including transit facilities and services, road traffic patterns and volumes, and parking. Environmental documents for transit projects should include a discussion of potential transportation impacts and their impact on the environment, human and natural, as applicable. Learn more

Water Resources
Under NEPA, the effects of a proposed project on water resources (including coastal zones, floodplains, navigable waterways, water quality and stormwater, wetlands and other Waters of the U.S.) must be considered. Learn more

Transit projects may impact utilities by disrupting service during construction. Impacts may include requiring utility relocation or adjustment of utility lines and facilities. Utilities affected may include municipal agencies, special utility districts, and private companies that provide services such as electricity, natural gas, water, wastewater or stormwater collection, and telecommunications.  Assessing the impact to utilities should be included in any NEPA document.

Indirect and Cumulative Impacts
NEPA requires that any agency proposing a major federal action, which may significantly affect the environment, consider the environmental impacts of the proposed action, any unavoidable adverse environmental impacts, and the relationship between local short term uses and long term productivity of the environment (42 USC § 4332(c)).
There are three types or categories of effect that must be considered during the NEPA process: direct, indirect, and cumulative (40 CFR § 1508.25). A direct effect is one which is caused directly by our activities, at the same time, and in the same place.  An indirect effect is a reasonably foreseeable effect caused by the proposed action or alternatives, but occurs later in time or are further removed from the project site than a direct effect. “Indirect effects may include growth inducing effects and other effects related to induced changes in the pattern of land use, population density or growth rate,” and related effects on resources (40 CFR § 1508.8(b)). A cumulative effect is an “impact on the environment which results from the incremental effect of the action when added to other past, present, and reasonably foreseeable future actions” (40 CFR § 1508.7). Cumulative effects can result from individually minor but collectively significant actions taking place over time (40 CFR § 1508.7).

When is an indirect effect or cumulative effect analysis required?
An indirect effects analysis is required when a project has the potential to cause induced changes to resources or growth inducing impacts – most transportation projects have the potential to cause such an impact due to changes in land use, population density and economic development. For example, a new/extension transit line may cause an increase in transit ridership and an associated decrease in automobile usage (thereby reducing fuel consumption and causing an indirect but possibly positive impact on energy consumption).

A cumulative effects analysis is required whenever an EA or EIS is prepared. The proposed project must have a direct and/or indirect effect on a specific resource for the proposal or alternative to exert a cumulative influence, therefore a CE project generally does not require cumulative analysis, unless there is an unusual circumstance (usually very rare). If no direct and/or indirect effect to a specific resource is expected, there is no need to consider cumulative effects to that resource.

What should the analysis include?
Separate analyses should be conducted to evaluate indirect effects of transportation projects and to evaluate project-related cumulative impacts. Both processes, however, should include consultation with stakeholders and the public, identification of important trends and issues, and analysis of the potential for land use changes and related environmental impacts on valued and vulnerable resources.

An indirect effects analysis must identify all reasonably foreseeable indirect effects, and the environmental document must make a “good-faith effort” to explain and evaluate them. If there is uncertainty about future land use, the lead agency is not required to engage in speculation but should make a judgment based on reasonably foreseeable occurrences (CEQ 40 Questions, No. 18). The National Cooperative Highway Research Program prepared Report 466: Desk Reference for Estimating the Indirect Effects of Proposed Transportation Projects (2002) which presents a step-by-step process for evaluating the indirect effects of transportation projects.

A complete cumulative effects analysis cannot be conducted until the direct impacts and the indirect effects have been identified in the environmental process.While NEPA requires that cumulative analysis is conducted on a detailed level for all alternatives, it is recommended that if a preferred alternative is selected for environmental review, that the extensive cumulative effects analysis focus on the preferred alternative and the future no-build option for a comparative view. The CEQ handbook entitled “Considering Cumulative Effects under NEPA” (CEQ 1997) provides guidance for reviewers to determine whether the cumulative impacts assessment in a NEPA document is adequate.

Additional Resources:
Federal Highway Administration's Environmental Guidebook

NCHRP Report 466: Desk Reference for Estimating the Indirect Effects of Proposed Transportation Projects (2002)

CEQ handbook Considering Cumulative Effects under NEPA (1997)

Updated: Thursday, March 24, 2016
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