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Guidance provided for constructing successful wetlands

Release Date: 4/19/2004
Contact Information: Joan Cabreza
(206) 553-1200

April 19, 2004

Studies show that many projects designed to replace lost wetlands don't work as well as intended, so state and federal environmental agencies have joined forces to issue guidance on how to make those projects more successful. The Washington State Department of Ecology (Ecology), U.S. Environmental Protection Agency (EPA) and U.S. Army Corps of Engineers have issued a two-part guidance document, entitled Guidance on Wetland Mitigation in Washington State. It was developed under an EPA grant to Ecology to replace guidance from 1994.

Photo of wetlandPart 1 of the report describes the laws, rules, policies and guidance related to wetland mitigation (replacement) and is intended to provide an overview of wetland regulatory programs in Washington, describe the basic elements of the mitigation process, and provide detailed guidance on state and federal mitigation policies.

Part 2 of the report provides technical guidance for improving the success of wetland projects that are intended to compensate for wetlands lost through property development and other activities. It also identifies the information that the three agencies usually need to review and approve mitigation and monitoring plans, and describes methods for collecting necessary data and preparing those plans.

Public comment on the draft guidance documents is being accepted through May 18.

"We are learning more and more about why some wetland projects succeed and why others fail," said Dana Mock who coordinated the project for Ecology. "There's a lot of time and money being invested in compensating for wetlands that get developed. And when that mitigation fails, it's both a financial and environmental loss."

To be more successful, wetland compensation projects not only need to be designed better, but also placed in suitable locations that will be self-sustaining over the long-term. Planners need to consider whether there's an adequate source of water, the nature of the soils on the site, the landscape position and past uses of the site, whether it has connecting corridors to wildlife habitat or other wetlands, the presence of invasive species that would choke out native plants, long-term maintenance and other considerations.

Ecology's wetlands manager, Andy McMillan, said the common practice of constructing compensation wetlands close to the wetlands they're replacing is not always the best practice.

"It's more important to find a location that has the necessary physical characteristics to be successful," McMillan said. "Selecting an appropriate site helps ensure that the new wetland will provide the desired functions and be ecologically effective over the long-term."

The guidance was prepared as part of the federal government's National Wetlands Mitigation Action Plan, which is being implemented by federal agencies to improve the success of compensatory mitigation nationwide. Implementing the plan will enable the agencies and the public to make better decisions regarding where and how to restore, enhance and protect wetlands; improve the ability to measure and evaluate the success of mitigation efforts; and expand the public's access to information on the wetland mitigation activities.
    There are four public hearings scheduled to accept comments on the drafts.
    • April 26 in Lacey - 6 p.m. at the Department of Ecology auditorium, 300 Desmond Drive.
    • Two meetings on April 27 in Seattle - 1 p.m. and 6 p.m. at the U.S. Army Corps of Engineers, Galaxy Room, 4735 E. Marginal Way South.
    • April 28 in Kelso - 1 p.m. at the Red Lion Inn, 510 Kelso Drive.

Written comments may be e-mailed to or mailed to Dana Mock at Department of Ecology, P.O. Box 47600, Olympia, Wash., 98504-7600.
The report is available on-line at