Interagency wetland mitigation guidance

Wetland Mitigation in Washington State, Version 1, is a two-part interagency document providing guidance on wetland mitigation. You can access the current mitigation guidance document (Parts 1 and 2) below.

Updates in progress

We’re working with the Environmental Protection Agency (EPA) and the U.S. Army Corps of Engineers (Corps) to update our current interagency wetland mitigation guidance published in 2006. Since then, there have been changes in the world of wetland mitigation. A federal mitigation rule was issued in 2008, and we have developed several tools for incorporating a watershed approach, and calculating mitigation gains and wetland losses. In addition, many of the references and web links in the documents are no longer current. We are working to integrate these new tools and policy changes into a unified document to provide clear guidance on wetland mitigation goals and requirements. Our plan is to publish the updated guidance in 2020.

You can stay up to date on this process by signing up for email updates through our Wetlands Information Listserv.

Part 1 — Agency policies and guidance

Part 1 provides a brief background on wetlands, an overview of the factors that are considered in the agencies' permitting decisions, and detailed guidance on the agencies' policies on wetland mitigation, particularly compensatory mitigation.

Part 2 — Developing mitigation plans

Part 2 provides technical information on preparing plans for compensatory mitigation.

Monitoring guidance

The Corps issued a regulatory guidance letter to clarify monitoring requirements for compensatory mitigation projects. The Corps' Seattle District has incorporated the most recent guidance letter (RGL 08-03) into their monitoring requirements for compensatory mitigation projects.

Other mitigation resources

We have published a number of guidance documents designed to improve mitigation. For example, in 2009 and 2010, we published guidance on selecting wetland mitigation sites using a watershed approach for both Eastern and Western Washington. This and all other mitigation guidance is available on our Wetland Mitigation Resources page.

We announce when new guidance is available through our Wetlands Information email listserv.