Interagency Wetland Mitigation Guidance

Background Information

In 1994, the Corps, Ecology, EPA, Washington Department of Fish and Wildlife, and U.S. Fish and Wildlife Service jointly published the Guidelines for Developing Freshwater Mitigation Plans and Proposals (March 1994, Ecology Publication #94-29). Subsequently, Ecology published How Ecology Regulates Wetlands (April 1998, Publication No. 97-112). However, by 2002, it had become clear that these documents no longer fully reflected current policy nor current science. In response, Ecology, through a Wetland Program Development Grant from the U. S. Environmental Protection Agency (EPA), began an effort to update the guidance. The update was done in coordination with the Seattle District Corps of Engineers and the U.S. Environmental Protection Agency (Region 10). As part of the process, two public meetings were held (March 11, 2003 in Seattle and April 8, 2003 in Moses Lake) and we met with the Washington State Department of Transportation’s compensatory mitigation technical group to gather suggestions and new information for the updated guidance. In addition, we drew on the experience of natural resource agency staff and evaluated information from Ecology’s Washington State Wetland Mitigation Evaluation Study (Publication #s 00-06-016 and 02-06-009), Ecology’s best available science (BAS) for wetlands project, the National Research Council’s Compensating for Wetland Losses under the Clean Water Act, and other research. Ecology also received many comments over the Internet and by e-mail. The result is the substantially revised and expanded mitigation guidance.

The two-part guidance document does not itself institute any new wetland mitigation requirement but, rather, compiles current scientific information and incorporates the many changes in mitigation policy that have occurred over the past 10 years. It also provides insight into how the regulatory agencies implement their programs and make permit decisions with regard to mitigation. Part 1 of the document describes the laws, rules, policies, and guidance pertinent to wetland mitigation, provides an overview of wetland regulatory programs in Washington State, and discusses the basic elements of the mitigation process, particularly compensatory mitigation. Part 2 provides technical assistance for developing wetland mitigation plans and proposals. Please note that, while this guidance focuses on freshwater wetlands, it can also be applied to other aquatic resources such as estuarine and tidal wetlands, streams, and open waters, and their associated buffers. Also, it is important to realize that, while the technical sections of this guidance are intended to aid permit applicants and consultants in designing, constructing, and maintaining compensatory mitigation projects, project-specific mitigation requirements can supersede this general guidance.

The draft Guidance for Wetland Mitigation in Washington State was sent out for a 30-day public comment period (see below for links to the drafts), April 19th-May 18th, 2004 (View the Public Notice pdf, 67k).  The comment period was extended to June 1st, 2004 (Public Notice - Second Notice  pdf, 43k). During the comment period public meetings were held in Lacey, Seattle, Kelso, and Yakima. Comments were accepted at the public meetings as well as through email and postal mail.

Draft Part 1 – Laws, Rules, Policies, and Guidance Related to Wetland Mitigation (April 2004) - Publication #04-06-013A (pdf, 2.5 mb.)

Draft Part 2 – Guidelines for Developing Wetland Mitigation Plans and Proposals (April 2004) - Publication # 04-06-013B (pdf, 1.2 mb.)

Suggestions and comments from reviewers of the draft documents were incorporated in to the final document, where appropriate. The following document contains all of the comments received on the draft document and the agencies responses. 

Responses to Comments:  Draft Guidance on Wetland Mitigation in Washington State (Publication #06-06-012).

How does the 2008 federal Compensatory Mitigation Rule affect the WA State Guidance on Wetland Mitigation?

On March 31, 2008, the Corps and EPA announced the release of the Final Compensatory Mitigation Rule. The purpose of the rule is to clarify how to provide compensatory mitigation for unavoidable impacts to the Nation's wetlands and streams that are subject to Section 404 under the Clean Water Act. Ecology, the Corps Seattle District, and EPA Region 10 reviewed the final rule language and determined that the WA state guidance is generally consistent with the rule. 


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