SEPA Glossary: Key Terms & Definitions for Developers and Consultants

SEPA Key Terms & Definitions

Action: Any activity potentially subject to SEPA review, including project actions (e.g., construction projects) and non-project actions (e.g., comprehensive plans, regulations). See WAC 197-11-704.

Addendum: An environmental document used to provide additional information or analysis that does not substantially change the analysis of significant impacts and alternatives in existing environmental documents. See WAC 197-11-706.

Categorical Exemption: A category of actions that an agency has determined do not have a significant effect on the environment and are therefore exempt from SEPA review. See WAC 197-11-800 through 890.

Determination of Non-Significance (DNS): The written decision by the lead agency that a proposal is not likely to have a significant adverse environmental impact, and therefore an EIS is not required. See WAC 197-11-734.

Determination of Significance (DS): The written decision by the lead agency that a proposal is likely to have a significant adverse environmental impact, and therefore an EIS is required. See WAC 197-11-736.

Environmental Checklist: A standard form used by agencies to obtain information about a proposal to decide whether an EIS is required. See WAC 197-11-960.

Environmental Impact Statement (EIS): A detailed written statement that analyzes the environmental impacts of a proposed action, and its alternatives, as required by SEPA when the lead agency determines a proposal is likely to have significant adverse environmental impacts. See WAC 197-11-738.

Expanded Scoping: An optional process that allows agencies and the public to comment on a DS prior to the issuance of a scoping notice. See WAC 197-11-410.

Lead Agency: The agency responsible for complying with SEPA's procedural requirements for a specific proposal. See WAC 197-11-050 and 922 through 948.

Mitigated Determination of Non-Significance (MDNS): The written decision by the lead agency that includes mitigation measures to ensure a proposal will not have a significant adverse environmental impact. See WAC 197-11-350.

Mitigation: Avoiding, minimizing, rectifying, reducing, or compensating for adverse impacts. See WAC 197-11-768.

Phased Review: The process of dividing environmental analysis into phases, typically focusing on conceptual issues first and more detailed issues later. See WAC 197-11-060(5).

Planned Action: A development project whose impacts have been addressed by an EIS associated with a comprehensive plan or subarea plan. See RCW 43.21C.440 and WAC 197-11-164 through 172.

Project Action: A decision on a specific project, such as a construction or management activity located in a defined geographic area. See WAC 197-11-704(2)(a).

Responsible Official: The person designated by the lead agency to carry out the agency's SEPA duties and functions. See WAC 197-11-788.

Scoping: The process of identifying the range of proposed actions, alternatives, impacts, and mitigation measures to be analyzed in an EIS. See WAC 197-11-408.

SEPA Register: The official publication for agency SEPA actions, maintained by the Department of Ecology. See WAC 197-11-508.

SEPA Rules: Chapter 197-11 WAC, which contains the statewide regulations that implement SEPA.

Significant Impact: A reasonable likelihood of more than a moderate adverse impact on environmental quality. See WAC 197-11-794.

State Environmental Policy Act (SEPA): Chapter 43.21C RCW, the state law requiring state and local agencies to consider environmental factors when making decisions.

Supplemental EIS: An environmental document used to supplement an existing EIS when there are substantial changes to a proposal, or new information becomes available. See WAC 197-11-405(4) and 620.

Threshold Determination: The decision by the lead agency whether an EIS is required for a proposal. See WAC 197-11-310.

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A Note to Our Readers: We hope this guide is a valuable resource in helping you better understand the . However, it's not a substitute for professional advice and doesn't cover every scenario. Always consult with regulatory bodies and professionals for the most current advice and project-specific guidance.