The mitigation sequence set forth in this section should be applied after impact avoidance and minimization measures have been taken.
(a) Location and Timing of Mitigation.
(1) Restoration, creation, or enhancement actions should be undertaken on or adjacent to the site, or, where restoration, creation, or enhancement of a former wetland is proposed, within the same watershed. In-kind replacement of the impacted wetland is preferred for creation, restoration, or enhancement actions. The City may accept or recommend restoration, creation, or enhancement which is off site and/or out-of-kind, if the applicant can demonstrate that on-site or in-kind restoration, creation, or enhancement is unfeasible due to constraints such as parcel size or wetland type, or that a wetland of a different type or location is justified based on regional needs or functions;
(2) Whether occurring on site or off site, the mitigation project shall occur near an adequate water supply with a hydrologic connection to the wetland to ensure a successful wetlands development or restoration;
(3) Any approved proposal shall be completed before initiation of other permitted activities, unless a phased or concurrent schedule has also been approved by the Planning and Community Development Department;
(4) Wetland acreage replacement ratios shall be as specified in Table 14.88-IV;
(5) Credits from a wetland mitigation bank may be approved for use as compensation for unavoidable impacts to wetlands.
(i) This provision may be used when:
a. The bank is certified under Chapter
173-700 WAC;
b. The Planning and Community Development Director or designee determines that the wetland mitigation bank provides appropriate compensation for the authorized impacts; and
c. The proposed use of credits is consistent with the terms and conditions of the bank's certification.
(ii) Replacement ratios for projects using bank credits shall be consistent with replacement ratios specified in the bank's certification.
(iii) 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, the service area of the bank may include portions of more than one adjacent drainage basin for specific wetland functions.
(b) Mitigation Performance Standards.
(1) All reasonable measures shall be taken to avoid and reduce impacts. When such avoidance and reduction is not reasonable, adverse impacts to wetland functions and values shall be mitigated. Mitigation actions shall be implemented in the preferred sequence identified in Section
14.88.010(a). Proposals which include less preferred or compensatory mitigation shall demonstrate that:
(i) All reasonable measures will be taken to reduce impacts and losses to the original wetland;
(ii) No overall net loss will occur in wetland functions, values and acreage; and
(iii) The restored, created or enhanced wetland will be as persistent and sustainable as the wetland it replaces.
(c) Wetland Replacement Ratios.
(1) Where wetland alterations are permitted by this chapter, the applicant shall restore or create equivalent areas of wetlands in order to compensate for wetland losses. Equivalent areas shall be determined according to size, function, category, location, timing factors, and projected success of restoration or creation.
(2) Where wetland creation is proposed, all required buffers for the creation site shall be located on the proposed creation site. Properties adjacent to or abutting wetland creation projects shall not be responsible for providing any additional buffer requirements.
(3) The following acreage replacement ratios shall be used as targets. The Planning and Community Development Director may vary these standards if the applicant can demonstrate and the Planning and Community Development Director or designee agrees that the variation will provide adequate compensation for lost wetland area, functions and values, or if other circumstances as determined by the Planning and Community Development Department justify the variation.
(4) The qualified scientific professional in the wetlands report may, where feasible, recommend that restored or created wetlands shall be a higher wetland category than the altered wetland.
(d) The Planning and Community Development Director may increase the ratios under the following circumstances:
(1) Uncertainty exists as to the probable success of the proposed restoration or creation; or
(2) A significant period of time will elapse between impact and replication of wetland functions.
(e) All wetland restoration, creation and/or enhancement projects required pursuant to this chapter either as a permit condition or as the result of an enforcement action shall follow a mitigation plan prepared in conformance to the requirements of Section
14.88.275, Mitigation/Enhancement Plan Requirements.
(f) Mitigation ratios for the replacement of impacted wetlands shall be as listed in Table 14.88-IV. However, Table 14.88-IV shall not apply to bogs, because it is not possible to create or restore bogs due to their unique chemistry and hydrology. Therefore, impacts to bogs are considered to be a loss of functions and shall be avoided.
Table 14.88-IV: Wetland Mitigation Ratios |
|---|
Affected Wetland | Mitigation Type and Ratio |
|---|
Category | Re-establishment or Wetland Creation | Rehabilitation | Enhancement Only |
|---|
Category IV | 1.5:1 | 3:1 | 6:1 |
Category III | 2:1 | 4:1 | 8:1 |
Category II | 3:1 | 6:1 | 12:1 |
Category I – Forested | 6:1 | 12:1 | 24:1 |
Category I – Score Based | 4:1 | 8:1 | 16:1 |
Category I – Bog | Not considered possible | N/A | N/A |
(g) Buffer Mitigation Ratios. Impacts to buffers shall be mitigated at a minimum 1:1 ratio. Compensatory buffer mitigation shall replace those buffer functions lost from development.
(h) The applicant may propose innovative site design based on the best available science and pursuant to Section
14.88.298 if the innovative development design will achieve protection equivalent to or better than the standard provisions of this chapter. Approval of the innovative site design will be considered in combination with criteria listed in Section
14.88.298 if the design achieves the following:
(1) The site design avoids impacts to the critical area; or
(2) The site design increases the functions and/or values of the wetland and buffer with a combination of the following measures:
(i) Improving water quality functions and values of the wetland and buffer by reducing fine sediment and pollutant input in the watershed by increasing hydrologic retention and filtration;
(ii) Improving the hydrologic functions and values of the wetland and buffer by providing increased flood control adjacent to a stream channel or by improving water storage ability in the wetland system to increase groundwater recharge potential; and
(iii) Increasing habitat for aquatic, amphibian and invertebrate species and associated wetland bird and mammal species.
(i) Credit/Debit Method. As an alternative to the mitigation ratios found in the joint guidance Wetland Mitigation in Washington State Parts I and II (Ecology Publication No. 06-06-011a-b, Olympia, WA, March 2006), the Director or designee 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 Western Washington: Final Report, (Ecology Publication No. 10-06-011, Olympia, WA, March 2012, or as revised).
(Ord. 741, Sec. 2, 2007; Ord. 773, Sec. 2, 2008; Ord. 811, Sec. 92, 2010; Ord. 984 Sec. 3 (Exh. C), 2019)