
Wetland delineation establishes the existence (location) and physical limits (size) of a wetland for the purposes of federal, state, and local regulations. Wetland delineation is also an element of a “jurisdictional determination” identifying which water bodies, including wetlands, within the project boundaries meet the definition of "waters of the United States." More information on this can be found on the Seattle District Corps' Waters and Wetlands Information web page.
It may be necessary to hire a qualified wetland professional to assist with identifying and delineating wetlands using the methods listed above. For recommendations to help you locate and select a qualified wetland professional, click here (PDF, 81 kb).
A report that explains how the boundary was determined. It should include:
A description of how and when the delineation was conducted.
- Data sheets used to delineate the wetland area (for the Arid West region also use the new data sheets).
- A map (topographic and aerial site maps are very helpful) with data plots and the boundaries of the delineated wetland areas clearly identified.
- A soil survey map.
Click here for a checklist of information that should be included in a wetland delineation report as well as a sample outline for a report.
It is important to remember that it is the Corps of Engineers, not applicants or their consultants, that is responsible for determining whether or not a wetland is a water of the U.S. and thus regulated under the federal Clean Water Act (CWA). If the Corps determines that a wetland is not subject to regulation under the CWA, applicants should be aware that these wetlands may still be subject to regulation by Ecology as well as by local jurisdictions and should be delineating using the existing state delineation manual. For more information on Ecology's regulation of wetlands determined by the Corps to be non-jurisdictional due to their isolation from navigable waters, click here.
If you have any questions on implementation of the state delineation manual, email Tom Hruby at the Department of Ecology.
Regional Supplements to the 1987 Wetland Delineation ManualThere has been an ongoing effort by the Corps to "regionalize" the 1987
wetland delineation manual. The Corps has been working with states,
federal agencies, and others to develop supplemental regional criteria to
refine the 1987 delineation manual. Interim documents have been completed for both regions in
Washington and the appropriate Supplement should be used when conducting delineations in
those regions.
See the third and fourth bullets at the top of the page for more
information. |
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