New WDOE Wetland Rating Habitat Scores

By Emmett Pritchard

New guidance regarding use of the 2014 Wetland Rating System issued this past summer by the Washington Department of Ecology (WDOE) could have ramifications for project sites that contain certain types of wetlands. The new guidance was provided by WDOE for use by cities and counties in both Western and Eastern Washington in setting buffer widths for wetlands that provide a moderate level of habitat function. WDOE made the changes based on public feedback and on its own review of data used to calibrate the rating system. The WDOE guidance relies on best available science and takes a moderate risk approach to wetland protection.

The new WDOE guidance now groups habitat scores of 3 to 5 points into low habitat function and scores of 6 and 7 points into moderate habitat function. Previously, wetlands that scored 5 points for habitat function were considered to provide a moderate level of function and were given wider buffers than wetlands that provided a low level of that function.

Local jurisdictions are not required to adopt the new WDOE guidance. However, WDOE is recommending that local jurisdictions that are in the process of updating their critical areas ordinances (CAO) use the new guidance for habitat scores and buffers. For jurisdictions that have recently completed their CAO updates, it is not mandatory to use the new guidance. However, depending on a jurisdiction’s specific circumstances, it may consider modifying the CAO through an administrative decision to utilize the new guidance. For example, in December 2018, Pierce County authorized use of the new WDOE guidance because it is based on best available science.