A. Mitigation for alterations to wetlands may be by restoring former wetlands, creating wetlands, or enhancing degraded wetlands, consistent with the Department of Ecology Guidelines for Developing Freshwater Wetlands Mitigation Plans and Proposals, 2004, as revised.

B. Mitigation shall generally replace wetland functions lost from the altered wetland except that the town may permit out-of-kind replacement when the lost functions are minimal or less important to the drainage basin than the functions that the mitigation action seeks to augment.

C. Mitigation shall be in the same drainage basin as the altered wetland. Wetland mitigation shall be in the same sub-basin unless a higher level of ecological functioning would result from an alternate approach.

D. Mitigation projects shall be completed as quickly as possible consistent with such factors as rainfall and seasonal sensitivity of fish, wildlife, and flora.

E. Mitigation projects shall be designed with reference to Wetland Replacement Ratios: Defining Equivalency, Washington Department of Ecology, 1992, Publication No. 92-08; Freshwater Wetlands in Washington State, Volume 2, Appendix 8-C; and similar science. Mitigation projects shall score the impact site and the mitigation site using the Wetland Rating Data Form of the Revised Washington State Wetlands Rating System for Western Washington. The aggregate total of wetland functions and values after mitigation, altered and mitigation sites combined, shall be at least 50 percent greater than the aggregate total before mitigation; provided, that this replacement ratio (1.5-to-1, non-acreage-based) shall be increased as necessary to compensate for mitigation that:

F. Because the above replacement ratio is based on a before-and-after count of functions and values, not acreage, it accounts, without need for further adjustment, for mitigation that would result in a lower category wetland than the wetland being impacted, and mitigation that would enhance as opposed to create or restore a wetland. In the case of enhancement, wetland acreage may decline though wetland functions and values would increase. Enhancement proposals shall be based on a sound understanding of the mitigation site’s pre- and post-mitigation functions and values.

G. Credits granted from a certified wetland mitigation bank shall be consistent with the bank’s certification and service area.

H. The applicant shall provide an as-built plan of the mitigation site and monitor the site in accordance with SPMC 15.18.110. [Ord. 492 § 3 (Exh. B § 125), 2007.]