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Article XI. Wetlands
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A. Designating Wetlands. Wetlands are those areas, designated in accordance with the approved federal wetland delineation manual and applicable regional supplement, that are inundated or saturated by surface or groundwater at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. All areas within the city meeting the wetland designation criteria in the federal wetland delineation manual and applicable regional supplement, regardless of any formal identification, are hereby designated critical areas and are subject to the provisions of this chapter. Wetland delineations are valid for five years; after such date the city shall determine whether a revision or additional assessment is necessary.

B. Wetland Ratings. Wetlands shall be rated according to the Washington State Department of Ecology wetland rating system found in the Washington State Wetland Rating System documents (Washington State Wetland Rating Manual for Western Washington (revised), Department of Ecology Publication No. 14-06-029) or as revised by Ecology. These documents contain the definitions and methods for determining if the criteria below are met.

1. Wetland Rating Categories.

a. Category I. Category I wetlands are those wetlands that (1) represent a unique or rare wetland type; or (2) are more sensitive to disturbance than most wetlands; or (3) are relatively undisturbed and contain ecological attributes that are impossible to replace within a human lifetime; or (4) provide a high level of functions. These include bogs, mature and old-growth forested wetlands, wetlands of high conservation value, and wetlands that perform many functions very well (score 23 points or more (out of 27) on a completed rating form for the appropriate hydro-geomorphic class).

b. Category II. Category II wetlands are difficult, though not impossible, to replace, and provide high levels of some functions. These wetlands occur more commonly than Category I wetlands, but still need a relatively high level of protection. Category II wetlands are those that score between 20 and 22 (out of 27) points. These wetlands were judged to perform most functions relatively well, or performed one group of functions very well and the other two moderately well.

c. Category III. Category III wetlands are wetlands with a moderate level of functions (scores between 16 and 19 points out of 27) and can often be adequately replaced with a well-planned mitigation project. These wetlands generally have been disturbed in some ways, and are often less diverse or more isolated from other natural resources in the landscape than Category II wetlands.

d. Category IV. Category IV wetlands have the lowest levels of functions (scores less than 16 points out of 27) and are often heavily disturbed. These are wetlands that should be able to be replaced, and in some cases be able to be improved. However, experience has shown that replacement cannot be guaranteed in any specific case. These wetlands may provide some important functions, and also need to be protected.

2. Date of Wetland Rating. Wetland rating categories shall be applied based on existing conditions at the time of application, or at the time of wetland delineation if within five years of application. Wetland rating categories shall not change due to illegal modifications.

C. Mapping. The approximate location and extent of wetlands are shown on the city’s current critical area maps. Additionally, soil maps produced by the U.S. Department of Agriculture Natural Resources Conservation Service may be useful in helping to identify potential wetland areas.

These maps are to be used as a guide for the city, project applicants, and/or property owners, and may be continuously updated as new critical areas are identified. They are a reference and do not provide a final critical area designation.

The exact location of a wetland’s boundary shall be determined through the performance of a field investigation by a qualified professional wetland scientist applying the federal wetland delineation manual and applicable regional supplement. (Ord. 2349 §§ 1, 2, 2021; Ord. 2010 § 1 (Exh. B), 2009; Ord. 1946 § 3, 2005).