NEPA & SEPA guidance

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Use the guidance on this page to appropriately disclose potential project impacts through the NEPA and SEPA (National and State Environmental Policy Acts) processes for Washington State Department of Transportation (WSDOT) environmental documents. Documents prepared under Local Programs (LP) should visit the LP Environmental Services webpage.

Read Chapter 400: Environmental Review and Transportation Decision Making of the Environmental Manual to learn more about our NEPA and SEPA processes as shown in the graphic below.

View this graphic for an overview of the NEPA process (pdf 282 kb)

Documenting environmental impacts through NEPA

The level and type of analysis required for a project varies by discipline and depends on the significance, complexity, and contextual setting of the actions being taken. Although most of the agency’s projects fit categories of exclusion, the complexity of the EA/EIS processes requires more guidance.

Before you begin documenting project impacts, read these documents to understand the Washington State Department of Transportation’s (WSDOT) role in the environmental documentation and review process of a federal project:

The FHWA Stewardship and Oversight Agreement with WSDOT (pdf 1 mb) documents roles and responsibilities related to project approvals and methods of oversight to deliver the Federal-aid Highway Program in accordance with Federal requirements.

The NEPA Documentation Roles and Responsibilities (pdf 149 kb) table defines the roles and responsibilities of WSDOT project teams, Environmental Services Office (ESO) Discipline and NEPA Specialists, and the Federal lead agency at specific phases of the environmental documentation process.

The Federal Nexus Requirements (pdf 736 kb) table can help you understand which regulations your project must comply with based on your federal nexus.

This page provides guidance for documenting impacts for a CE level project. Projects not likely to cause significant adverse environmental impacts are classified as NEPA CEs.

CEs typically do not involve impacts to growth or land use; relocation of significant numbers of people; or significant air, noise, or water quality impacts. Past experience shows that CE projects typically have only minor impacts to cultural, recreational, historic, or other resources, and the projects are not controversial for environmental reasons.

Guidance for project leads and analysts preparing an EIS or EA for a proposed project.

Projects likely to have a significant impact on the natural or built environment require an Environmental Impact Statement. The EIS describes all short and long-term environmental impacts, project benefits, and mitigation measures. An EIS requires a public process to foster an open and collaborative decision-making process.

Projects with impacts that are not clearly understood require an Environmental Assessment (EA). The EA describes the extent and level of environmental impact. The document will either support a Finding of No Significance (FONSI) or indicate that an EIS is warranted.

This page provides more information on how WSDOT implements SEPA (State Environmental Policy Act) on projects. Review the law along with the Department of Ecology’s guidance, rules, and forms.

Guides for project teams in the preparation of environmental impact statements (EISs) and environmental assessments (EAs), but many of the tips also apply to categorical exclusions (CEs).