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. If you are interested in why, when, and how the document was developed you can read the background information.

Updating our wetland mitigation guidance

We’re working with the Environmental Protection Agency (EPA) and the US Army Corps of Engineers (Corps) to update our interagency wetland mitigation guidance.

Our current guidance was published in 2006. Since then, there have been changes in the world of wetland mitigation. A federal mitigation rule was issued in 2008, and Ecology has 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 In addition, many of the references and web links in the documents are no longer current. Our goal is to integrate these new tools and policy changes into a unified document that will provide clear guidance on wetland mitigation goals and requirements. We plan to have the updated guidance by May 2018.

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. It replaces the portions of the 1997 Ecology publication, How Ecology Regulates Wetlands (Publication #97-112), pertaining to wetland mitigation.

Download Document

Part 2 - Developing Mitigation Plans

Part 2 provides technical information on preparing plans for compensatory mitigation. It updates and replaces the 1994 Guidelines for Developing Freshwater Mitigation Plans and Proposals (Publication #94-29).

Download Document

Links to More Guidance

Monitoring Guidance

The U.S. Army Corps of Engineers (Corps) issued a Regulatory Guidance Letter to clarify monitoring requirements for compensatory mitigation projects.  The Corps, Seattle District, has incorporated the most recent Regulatory Guidance Letter (RGL) 08-03 into their monitoring requirements for compensatory mitigation projects. > More on Compensatory Mitigation Monitoring Requirements.

Mitigation that Works

We are in the process of developing a number of guidance documents with the goal of improving mitigation.  For example, in 2009 and 2010, Ecology 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 Ecology's Mitigation Resources web page.  We make announcements about the availability of any new guidance to the Wetlands Information Listserv.

If you have any questions contact Dana L. Mock, 360-407-6947.


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