Regulatory Updates

WDOE Revised Wetland Ratings

Bald Eagle Listing Update

WDOE and COE Mitigation Requirements

WDOE Wetland Ratings

New Nationwide Permit Authorization

New Guidance for Wetland Jurisdiction  

The Washington State Growth Management Act (GMA) requires all counties and cities in Washington to review and update their critical areas ordinances every 7 years.  During the latest round of critical areas updates, a majority of the jurisdictions in Washington State adopted Washington State Department of Ecology’s (WDOE’s) revised wetland rating systems for western and eastern Washington.  The wetland rating is intended to guide management decisions such as wetland buffer widths, permitted uses within the wetland, and mitigation ratios to compensate for direct impacts to a wetland.

The revised WDOE rating system places wetlands into 4 categories based on wetland functions, sensitivity to disturbance, rarity, and or ability to replace them.  While some rare or sensitive wetlands automatically receive higher categorization, most often wetland ratings are based on their water quality, hydrologic, and habitat functions.

Most jurisdictions that use the WDOE rating system determine compensatory mitigation ratios solely based on the category of a wetland.  However, buffer widths may be highly variable, even for wetlands within the same category, depending on the habitat and/or water quality score a wetland receives.  For instance, a Category III wetland in unincorporated King County may have a buffer width of 75 to 125 feet, depending on its habitat score.  While most jurisdictions that use this type of buffer designation assign one buffer width for a range of habitat scores, some jurisdictions assign wetland buffer widths on a point-by-point basis once the habitat score exceeds a certain threshold.

WDOE asserts that the variability in scores among people trained to use the WDOE rating system is plus-or-minus 5 points, while untrained people may have as much as a 15-point variability in scoring.  WDOE released annotated versions of the rating systems for western and eastern Washington in 2006 and 2007, respectively.  The annotated versions generally require more detailed mapping of wetland systems to demonstrate how a wetland was scored for hydrologic, water quality, and habitat functions.

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