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Environmental Impact Statement Process

  EA NEPA process flow chart - thumb nail
NEPA Process Flow Chart -- click image to enlarge.

An Environmental Impact Statement (EIS) is required for actions that are likely to have a significant impact the natural or built environment. The EIS describes 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.

The information on this page is designed for a technical audience.

Chapter 400 of the Environmental Manual (EM) describes policies that must be considered when completing an EIS.


Document Impacts

Document Review and Inviting Comments 

Re-evaluations and Supplemental Documents

Adopting NEPA Documents Under SEPA Rules

As a matter of practice, Project Teams should complete the NEPA and SEPA environmental review process simultaneously in a single document.  When a NEPA document is completed without considering SEPA, that NEPA EA/EIS can be adopted using the form found in WAC 197-11-965 .  The form/determination notice is signed according to agency SEPA delegations:  the ESO Director signs an EIS/EA, the Region/Mode Environmental Manager signs a DNS.

Document Basics

EIS Resources

  • NCHRP Project 20-24, Task 71, Phase 2: Expediting NEPA Decisions and Other Practitioner Strategies for Addressing High Risk Issues in Project Delivery. (June 2014)
  • eNEPA - Project Management -- An Introduction to FHWA eNEPA and link to this optional tool for collaboration on EA/EIS level projects.
  • NEPA/SEPA documentation GIS layer available on WSDOT Environmental Workbench -- useful for identifying if any larger environmental documents were previously completed in your project area.  The information primarily includes only EA and EIS documents.  For access contact your Region Environmental Coordinator.
  • FHWA Technical Advisory TA6640.8a   Section V includes the cover sheet, outline, and description of recommended content for each section of the document.
  • WSDOT Limited English Proficiency web page.