Ord 2625 - TMC Title 18 Chapters - Critical Areas Regulations

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F. WETLAND MITIGATION PLAN CONTENT. 1. The mitigation plan shall be developed as part of a critical area study by a qualified professional. Wetland and/or buffer alteration or relocation may be allowed only when a mitigation plan clearly demonstrates that the changes would be an improvement of wetland and buffer quantitative and qualitative functions. The plan shall show how water quality, habitat, and hydrology would be improved. 2. The scope and content of a mitigation plan shall be decided on a case -by - case basis taking into account the degree of impact and the extent of the mitigation measures needed. As the impacts to the critical area increase, the mitigation measures to offset these impacts will increase in number and complexity. 3. For wetlands, the format of the mitigation plan should follow that established in Wetland Mitigation in Washington State, Part 2 — Developing Mitigation Plans (Washington Department of Ecology, Corps of Engineers, EPA, March 2006 or as amended). 4. The components of a complete mitigation plan are as follows: a. Baseline information of quantitative data collection or a review and synthesis of existing data for both the project impact zone and the proposed mitigation site. b. Environmental goals and objectives that describe the purposes of the mitigation measures. This should include a description of site selection criteria, identification of target evaluation species and resource functions. c. Performance standards of the specific criteria for fulfilling environmental goals and for beginning remedial action or contingency measures. They may include water quality standards, species richness and diversity targets, habitat diversity indices, or other ecological, geological or hydrological criteria. d. A detailed construction plan of the written specifications and descriptions of mitigation techniques. This plan should include the proposed construction sequence, construction management and tree protection and be accompanied by detailed site diagrams and blueprints that are an integral requirement of any development proposal. e. A monitoring and/or evaluation program that outlines the performance standards and methods for assessing whether those performance standards are achieved during the specified monitoring period, at least 5 years. At a minimum, the monitoring plan should address vegetative cover, survival, and species diversity. Any project that alters the dimensions of a wetland or creates a new wetland shall also monitor wetland hydrology. An outline shall be included that spells out how the monitoring data will be evaluated by agencies that are tracking the mitigation project's progress. f. Contingency plan identifying potential courses of action and any corrective measures to be taken when monitoring or evaluation indicates project performance standards have not been met. g. Performance security or other assurance devices as described in TMC Section 18.45.210. MLegislative Development\Critical Areas update 2-25-20 MD:bjs Review and analysis by Barbara Saxton Page 27 of 87