A. Rating categories. Wetlands shall be rated Category I, II, III, or IV according to the Department of Ecology’s Washington State Wetland Rating System for Western Washington (Ecology Publication #04-06-025). (See WAC 365-190-080(1)(a).) Wetland categories shall apply to the wetland as it exists on the date the City adopts the rating system, as the wetland naturally changes thereafter, or as the wetland changes in accordance with permitted activities. Wetland rating categories shall not change due to illegal modifications. The City will conduct an analysis of new wetlands rating systems as proposed by the State on an annual basis for consideration as an amendment to this chapter.
B. Designating Wetlands.
1. As set forth in RCW 36.70A.030(20), wetlands are those areas that are inundated or saturated by surface or ground water at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs, and similar areas. Wetlands do not include those artificial wetlands intentionally created from non-wetland sites, including, but not limited to, irrigation and drainage ditches, grass-lined swales, canals, detention facilities, wastewater treatment facilities, farm ponds, and landscape amenities, or those wetlands created after July 1, 1990, that were unintentionally created as a result of the construction of a road, street, or highway. Wetlands may include those artificial wetlands intentionally created from non-wetland areas to mitigate conversion of wetlands.
2. Pursuant to RCW 36.70A.175, wetlands are designated in accordance with the Washington State Wetland Identification and Delineation Manual (Ecology Publication #96-94).
3. The City has maps showing the approximate location and extent of wetlands. However, these maps are only a guide and will be updated as critical areas become better known. The exact location of a wetland’s boundary shall be determined in accordance with the above-referenced manual.
C. Rating wetlands. Wetlands shall be rated according to the Department of Ecology wetland rating system, as set forth in the Washington State Wetland Rating System for Western Washington (Ecology Publication #04-06-025, or as revised and approved by DOE). These documents contain the definitions and methods for determining if the criteria below are met.
1. Category I. Category I wetlands are those wetlands that meet any of the following criteria:
a. Wetlands that are identified by scientists of the Washington Natural Heritage Program/DNR as high quality wetlands;
b. Bogs larger than a half acre;
c. Mature and old growth forested wetlands larger than one acre;
d. Wetlands that perform many functions well (score at least 70 points); or
e. Wetlands that:
i. represent a unique or rare wetland type; or
ii. are more sensitive to disturbance than most wetlands; or
iii. are relatively undisturbed and contain ecological attributes that are impossible to replace within a human lifetime; or
iv. provide a high level of functions.
2. Category II. Category II wetlands are those wetlands that meet any of the following criteria:
a. A wetland identified by the Washington State Department of Natural Resources as containing “sensitive” plant species;
b. A bog between one-quarter and one-half acre in size; or
c. Wetlands with a moderately high level of functions (score between 51 and 69 points).
3. Category III. Category III wetlands are wetlands with a moderate level of functions (score between 30 and 50 points), which generally have been disturbed in some way and which are often less diverse or more isolated from other natural resources in the landscape than Category II wetlands.
4. Category IV. Category IV wetlands have the lowest levels of functions(score less than 30 points) and are often heavily disturbed. These are wetlands that should be replaceable and in some cases improvable. However, experience has shown that replacement cannot be guaranteed in any specific case. These wetlands may provide some important functions and should be protected to some degree.
D. Date of wetland rating. Wetland rating categories shall be applied as the wetland exists on the date of adoption of the rating system by the local government, as the wetland naturally changes thereafter, or as the wetland changes in accordance with permitted activities. Wetland rating categories shall not change due to illegal modifications.