Ordinance 2213-97 - Laserfiche WebLink

• Table 4-1 provides a summary of potential wetland mitigations by basin. Note that where mitigation measures include raising the elevation of outlets in flow through riparian systems, the mitigation will be subject to site-specific analysis addressing the feasibility of the mitigation. The mitigation shall not be used for meeting on-site stormwater detention requirements. The intent is to create additional wetlands and increase the range of water depths to approximately .5 to 2 feet so that a mosaic of emergent, scrub shrub and open water habitat would be created. The intent is to significantly improve the habitat functions.4 The detailed wetland mitigation plan/report must demonstrate that wildlife habitat will be significantly improved by the proposed mitigation and that raising the outlet elevation will not result in degradation of the existing wetland. Mitigation must also be designed to ensure that stability of adjacent slopes is not impacted and that the mitigation will not adversely impact adjacent or downstream properties. • Acquisition of properties containing wetlands that would otherwise be filled in order to permit reasonable use of the property, rather than constructing compensation/mitigation. The Planning Director must approve the specific wetland site to be acquired. These properties must be permanently protected by deed restrictions, dedication to the City, or other means approved by the Planning Director. If the City establishes a fund to purchase "reasonable use" properties, the applicant may be permitted to contribute to such a fund. The amount of the contribution will be determined per an administrative manual developed at time of creation of the fund. • Mitigation in drainage basins outside of the Study Area may also be approved by the Planning Director, subject to a case-by-case analysis. For example, mitigation may be proposed in the North Creek or Swamp Creek drainage basins, or in the Snohomish River estuary. At this time, there is no scientific basis for trading off wetland functions for "out-of-kind" mitigation (such as creating estuarine wetland to compensate for palustrine or riparian wetlands). Therefore, when out-of-kind mitigation is proposed, mitigation ratios found in Chapter 37 of the Zoning Code shall be doubled at a minimum, with the actual mitigation ratio to be determined by the Planning Director. • If the City or other agency establishes a functioning mitigation bank that is performing wetland functions satisfactorily, the applicant may, subject to a case-by-case approval by the City, be allowed to purchase credits rather than constructing compensation/mitigation. For a City bank, mitigation shall be provided per an administrative manual developed at time of creation of the mitigation bank. If the mitigation bank is established by another agency, mitigation ratios shall be per the City Zoning Code or the agency banking agreement, whichever is greater. (SEPA Land and Shoreline Use, Water, and Plant and Animal Policies) a Restricting the outlet can also significantly improve the water quality improvement functions, while also providing some stormwater detention function (see the Wetland and Buffer Functions Semi-Quantitative Assessment Methodology). However,the mitigation cannot be used to meet required stormwater treatment and detention requirements. 27