16.50.280 Compensatory Mitigation Pertaining to Wetlands.
(1) Compensatory Mitigation Plans. Projects that propose compensation for wetland acreage and/or functions are subject to state and federal regulations. Compensatory mitigation for alterations to wetlands shall provide for no net loss of wetland functions and values. Compensatory mitigation for alterations to wetlands shall be used only for impacts that cannot be avoided or minimized and shall achieve equivalent or greater biologic functions. Compensatory mitigation plans shall be consistent with the mitigation plan requirements of Section 16.50.180; Wetland Mitigation in Washington State – Part 2: Developing Mitigation Plans – Version 1, (Ecology Publication #06-06-011b, Olympia, WA, March 2006 or as amended); and Selecting Wetland Mitigation Sites Using a Watershed Approach (Eastern Washington) (Publication #10-06-07, November 2010 or as amended).
(2) Mitigation for Lost Functions and Values. Mitigation actions shall address functions affected by the alteration to achieve functional equivalency or improvement, and shall provide similar wetland functions as those lost except when:
(a) the lost wetland provides minimal functions as determined by a site-specific function assessment and the proposed mitigation action(s) will provide equal or greater functions or will provide functions shown to be limiting within a watershed through a formal watershed assessment protocol; or
(b) out of kind replacement will best meet formally identified regional goals, such as replacement of historically diminished wetland types.
(3) Preference of Mitigation Actions. Mitigation actions that require compensation by replacing, enhancing, or substitution, shall occur in the following order of preference:
(a) restoring wetlands on upland sites that were formerly wetlands;
(b) creating wetlands on disturbed upland sites such as those with vegetative cover consisting primarily of exotic introduced species;
(c) enhancing significantly degraded wetlands;
(d) preserving high-quality wetlands that are under imminent threat.
(4) Location of Mitigation.
(a) Mitigation actions shall be conducted on the same site as the alteration except when the following apply:
(i) there are no reasonable on-site opportunities or on-site opportunities do not have a high likelihood of success due to development pressures, adjacent land uses, or on-site buffers or connectivity are inadequate;
(ii) off-site mitigation has a greater likelihood of providing equal or improved wetland functions than the impacted wetland.
(b) If the Director of Community Development authorizes off-site mitigation, the location of this mitigation shall be in the same drainage basin and the same Water Resource Inventory Area (WRIA) as the site of the alteration unless:
(i) established regional or watershed goals for water quality, flood or conveyance, habitat, or other wetland functions have been established and strongly justify location of mitigation at another site; or
(ii) credits from a state certified wetland mitigation bank are used as mitigation and the use of these credits justifies location of mitigation at another site.
(c) Off-site locations for mitigation should be within the city limits if feasible opportunities for appropriate mitigation are available.
(5) Mitigation Ratios.
(a) Wetland mitigation ratios shall be consistent with Table 16.50.3 below.
Category and Type of Wetland | Creation or Reestablishment | Rehabilitation | Enhancement |
|---|---|---|---|
Category I: Bog, Wetlands with High Conservation Value | Not considered possible | Case by case | Case by case |
Category I: Forested | 6:1 | 12:1 | 24:1 |
Category I: Based on functions | 4:1 | 8:1 | 16:1 |
Category II | 3:1 | 6:1 | 12:1 |
Category III | 2:1 | 4:1 | 8:1 |
Category IV | 1.5:1 | 3:1 | 6:1 |
(b) To more fully protect functions and values, and as an alternative to the mitigation ratios in Table 16.50.3, the Director of Community Development may allow mitigation based on the “credit/debit” method developed by the Department of Ecology in “Calculating Credits and Debits for Compensatory Mitigation in Wetlands of Eastern Washington: Final Report” (Ecology Publication #11-06-015, August 2012, or as amended).
(c) Impacts to wetland buffers shall be mitigated at a 1:1 ratio. Compensatory buffer mitigation shall replace those buffer functions lost from development.
(6) Wetland Mitigation Banks.
(a) Credits from a wetland mitigation bank may be approved for use as compensation for unavoidable impacts to wetlands when:
(i) the bank is certified through applicable provisions administered by the Department of Ecology and the Army Corps of Engineers;
(ii) the Director of Community Development determines that the wetland mitigation bank provides appropriate compensation for the authorized impacts; and
(iii) the proposed use of credits is consistent with the terms and conditions of the bank’s certification.
(b) Replacement ratios for projects using bank credits shall be consistent with replacement ratios specified in the bank’s certification.
(c) Credits from a certified wetland mitigation bank may be used to compensate for impacts located within the service area specified in the bank’s certification. In some cases, bank service areas may include portions of more than one WRIA for specific wetland functions.
(7) Advance Mitigation. Mitigation for projects with pre-identified impacts to wetlands may be constructed in advance of the impacts if the mitigation is implemented according to federal rules, state policy on advance mitigation, and state water quality regulations, consistent with Interagency Regulatory Guide: Advance Permittee Responsible Mitigation (Ecology Publication #12-06-015, Olympia, WA, December 2012 or as amended).
(8) Wetland Preservation as Mitigation. Preservation of high-quality, at-risk wetlands as compensation is generally acceptable when done in combination with restoration, creation, or enhancement, provided that a minimum of 1:1 acreage replacement is provided by re-establishment or creation. Ratios for preservation in combination with other forms of mitigation generally range from 10:1 to 20:1, as determined on a case-by-case basis, depending on the quality of the wetlands being altered and the quality of the wetlands being preserved. Preservation of high-quality, at-risk wetlands and habitat may be considered as the sole means of compensation for wetland impacts when the following criteria are met:
(a) The area proposed for preservation is of high quality. The following features may be indicative of high-quality sites:
(i) Category I or II wetland rating (using the wetland rating system for eastern Washington);
(ii) Rare wetland type (for example, bogs, mature forested wetlands, estuarine wetlands);
(iii) The presence of habitat for priority or locally important wildlife species; or,
(iv) Priority sites in an adopted watershed plan.
(b) Wetland impacts will not have a significant adverse impact on habitat for listed fish, or other ESA-listed species.
(c) There is no net loss of habitat functions within the watershed or basin.
(d) Mitigation ratios for preservation as the sole means of mitigation shall generally start at 20:1. Specific ratios should depend upon the significance of the preservation project and the quality of the wetland resources lost.
(e) Permanent preservation of the wetland and buffer will be provided through a conservation easement or tract held by a land trust.
(f) The impact area is small (generally less than half an acre) and/or impacts are occurring to a low-functioning system (Category III or IV wetland).
All preservation sites shall include buffer areas adequate to protect the habitat and its functions from encroachment and degradation. (Ord. 21-15 §6, 2021; Ord. 19-6 §15, 2019; Ord. 03-18 §29, 2003).