Environmental Impact Statement (EIS)/Environmental Assessment (EA) Processes

Follow directions on this page to complete your Environmental Assessment (EA) and Environmental Impact Statement (EIS) for NEPA (National Environmental Policy Act) documentation for a state transportation project. 

View this graphic for an overview of the EA or EIS process (201 kb).

Before you start

Review Chapter 400: Environmental Review and Transportation Decision Making of the Environmental Manual for policies that must be considered when completing an EA or EIS.

Preparing an EA and EIS

When to develop an EA level analysis

Prepare an EA when the environmental impact of a proposed project is not clearly understood. An EA describes the extent and level of environmental impact. The document will either support a Finding of No Significance (FONSI) or indicate the need for an EIS.

When to develop an EIS level analysis

Prepare an EIS for actions that are likely to have a significant impact the natural or built environment or are highly controversial. The EIS describes the extent and level of long and short-term environmental impacts, project benefits, and mitigation measures. Completion of an EIS requires an open public process proscribed by State and Federal Law.

Use these essential documents when working through either an EA or and EIS process:  

NEPA Documentation Roles and Responsibilities (pdf 137 kb) table details the specific roles and responsibilities of the WSDOT project teams, discipline specialists, Environmental Services Office, Federal Highway Administration (FHWA), and the State Responsible Official through the various stages of documentation. 

Preparing an EA (pdf 749 kb) procedure provides a step-by-step procedure from project assignment to issuance of a FONSI. 

Preparing an EIS (pdf 739 kb) procedure provides a step-by-step procedure from project assignment to issuance of the Record of Decision (ROD). This document contains information on creating an administrative record, developing coordination plans, writing discipline reports, and conducting signature briefings.

NEPA Re-evaluation

A re-evaluation establishes whether or not a previously approved NEPA document, determination, or decision remains valid. Re-evaluation generally occurs when a project has elements not previously evaluated (e.g., design changes) or when a “shelved” project comes back to life.

  • Re-evaluating an EA/EIS (pdf 321 kb) procedure provides a step-by-step procedure for re-evaluating the effects of a project.

Preparing quality environmental documents

This page guides project teams in the preparation of environmental impact statements and environmental assessments, but many of the tips also apply to documented categorical exclusions. This page provides resources for authors and reviewers to ensure NEPA/SEPA documents are of high quality and readable to the general public.

Environmental disciplines

The following pages provide specific direction and guidance for assessing impacts on the environment by discipline.

Air quality, noise, and energy

Cultural resources

Fish & wildlife

Hazardous materials

Social and Land use effects

Stream Restoration

Water resources & erosion control

Wetlands