16.55.350 Mitigation requirements specific to wetlands (see BMC 16.55.240, 16.55.250, and 16.55.260 for other mitigation requirements).
Compensatory mitigation for alterations to wetlands shall be used only for impacts that cannot be avoided or minimized and shall achieve equivalent or greater wetland functions. Mitigation plans shall be consistent with Wetland Mitigation in Washington State – Part 2: Developing Mitigation Plans (Ecology Publication No. 06-06-011b, Olympia, WA, March 2006 or as revised), and Selecting Wetland Mitigation Sites Using a Watershed Approach (Western Washington), (Ecology Publication No. 09-06-32, Olympia, WA, December 2009).
A. Preference of Mitigation Actions. Mitigation actions shall occur in the following order of preference after mitigation sequencing has been applied (see BMC 16.55.510 for full definitions of creation, enhancement, preservation, rehabilitation, reestablishment, and restoration):
1. Restoration (reestablishment and rehabilitation) of wetlands. Reestablishing wetlands is returning natural or historic functions to a former wetland. Rehabilitation of wetlands is repairing natural or historic functions of a degraded wetland
2. Creation (establishment) of wetlands.
3. Enhancement of significantly degraded wetlands in combination with restoration or creation. Such enhancement should be part of a mitigation package that includes replacing the impacted area to meet appropriate ratio requirements.
4. Preservation of high quality, at-risk wetlands when done in combination with restoration, creation, or enhancement.
B. Specific Types of Mitigation. The following types of mitigation are fully defined in BMC 16.55.510, Definitions. In the interest of consistency, they are the definitions provided by the Army Corps of Engineers in its “Regulatory Guidance Letter 02-02.” They have also been adopted by the Washington State Department of Ecology. Each is considered a type of “restoration” as defined in BMC 16.55.510: reestablishment, rehabilitation, creation (establishment), enhancement, preservation (protection/maintenance).
For the purposes of this chapter, the mitigation categories are:
1. Restoration. This includes reestablishment or rehabilitation.
2. Creation (establishment). Wetlands on disturbed upland sites such as those with vegetative cover consisting primarily of nonnative introduced species. This should only be attempted when there is a consistent source of hydrology and it can be shown that the surface and subsurface hydrologic regime is conducive for the wetland community that is being created.
3. Enhancement. Unlike restoration activities, enhancement results in a change of wetland functions, not a net gain of function or wetland acres.
4. Preservation. Preservation in combination with other forms of mitigation is allowed. Preservation as the sole means of mitigation for wetland impacts may be allowed if the wetland area to be preserved meets all of the following criteria:
a. The preserved wetland and buffer are protected in perpetuity through a conservation easement, deed restriction, or dedication as a separate tract;
b. The area proposed for preservation is of high quality (scores between 20 and 27 points in the wetland rating system), is located in the same watershed, and is critical to the health of the watershed or sub-basin. Some of the other high quality features include:
i. Rare wetland types such as bogs, mature forested wetlands, estuaries, or vital wildlife habitat;
ii. High regional or watershed importance;
iii. Large size with high species diversity (plants and/or animals) and a high abundance;
c. Preservation is used as a form of compensation only after the standard sequencing of mitigation (BMC 16.55.250) has been applied;
d. Creation, restoration, and enhancement opportunities have also been considered and preservation is the best mitigation option;
e. Preservation sites include buffer areas adequate to protect the habitat and its functions from encroachment and degradation;
f. The impacts are to a Category II, III, or IV wetland;
g. The preservation site is determined to be under imminent threat, specifically sites with the potential to experience a high rate of undesirable ecological change due to on- and/or off-site activities;
h. Replacement ratios are listed in Table 16.55.350. Replacement ratios for preservation used in combination with other forms of mitigation are to be determined by the director.
C. Location of Compensatory Mitigation. Site selection for compensatory mitigation shall be based on a location that will provide the greatest ecological benefit and have the greatest likelihood of success. Where feasible, mitigation shall occur in the same sub-basin as the permitted wetland alteration. However, if it can be demonstrated that a mitigation site in an alternative sub-basin or watershed would provide a greater ecological benefit and offer a more successful replacement of wetland functions and values, compensatory mitigation may take place in an alternative sub-basin or watershed. If a mitigation bank or in-lieu fee program is proposed for the required mitigation, documentation shall be provided that demonstrates there is an ecological benefit. The documentation shall also include how locating the mitigation out of the sub-basin or watershed will not impact other nearby critical areas.
D. Mitigation Banking. Mitigation banking is allowed for compensatory mitigation when all of the following are met:
1. The bank is certified under state rules;
2. The proposal to use the mitigation bank meets the certified banking instrument criteria;
3. Documentation is provided with the proposal that an alternatives analysis pursuant to BMC 16.55.210(C)(7) has been completed;
4. Documentation that mitigation sequencing pursuant to BMC 16.55.250 has been adhered to;
5. Documentation is provided that the bank is ecologically preferable and will provide a more successful replacement of wetland functions and values; and
6. The director determines that the wetland bank provides appropriate compensation for impacts.
E. In-Lieu Fee Mitigation. Development or use of an in-lieu fee program is allowed if the program is established consistent with federal and state regulations and policies. Using credits from an approved in-lieu-fee program shall be consistent with mitigation sequencing pursuant to BMC 16.55.250 and with state criteria.
F. Mitigation Ratios. The following ratios in Table 16.55.350 and consideration of factors described in this section shall be used to determine the relative amount of created, reestablished, restored, or enhanced wetlands that will be required to replace impacted wetlands. The first number refers to the amount of wetland area providing mitigation and the second refers to the amount of wetland area impacted or altered. If a mitigation bank or in-lieu program is used for mitigation requirements, wetland replacement ratios are not applied. The mitigation bank credit system, or in-lieu fee program credit system, whichever applies, is used to determine the number and cost of the credits to be purchased to fulfill mitigation requirements.
|
Creation or Reestablishment |
Restoration (Rehabilitation) |
Enhancement |
Preservation |
|
|---|---|---|---|---|
|
Category I BMC 16.55.280(A)(4). Mature forested wetland |
6:1 |
12:1 |
24:1 |
N/A |
|
Category I BMC 16.55.280(A)(6) scores 23 points or more in wetland rating |
4:1 |
8:1 |
16:1 |
N/A |
|
Category I BMC 16.55.280(A), all others |
Case-by-case basis; may not be possible |
Case-by-case basis; may not be possible |
Case-by-case basis; may not be possible |
N/A |
|
Category II |
3:1 |
6:1 |
12:1 |
16:1 |
|
Category III |
2:1 |
4:1 |
8:1 |
10:1 Case-by-case basis |
|
Category IV |
1.5:1 |
3:1 |
6:1 |
5:1 to 10:1 Case-by-case basis |
1. Provisions for Increasing or Decreasing Ratios. The director may increase or decrease the ratios based on one or more of the following:
a. Replacement ratios may be increased under the following circumstances:
i. Uncertainty exists as to the probable success of the proposed restoration or creation;
ii. A significant period of time will elapse between impact and establishment of wetland functions at the mitigation site;
iii. Proposed compensation will result in a lower category wetland or reduced functions relative to the wetland being impacted; or
iv. The impact was an unauthorized impact.
b. Replacement ratios may be decreased under the following circumstances:
i. The proposed mitigation actions are conducted in advance of the impact and are shown to be successful;
ii. Documentation by the applicant demonstrates that the proposed compensation actions will provide functions and values that are significantly greater than the wetland being impacted; or
iii. Documentation by the applicant provides more certainty that the proposed compensation action will be successful. Documentation could include extensive hydrologic data to support the proposed water regime.
2. Credit/Debit Method. As an alternative to using mitigation ratios for calculating mitigation requirements, the director may allow mitigation based on the “credit/debit” method as described 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).
G. Mitigation Report Requirements.
1. Prepared by a Qualified Professional. A wetland mitigation report shall be prepared by a qualified professional in accordance with BMC 16.55.510.
2. Report Requirements.
a. Detailed summary of the project, including the wetland and buffer impacts and the proposed mitigation, to appear in the beginning of the report;
b. Complete site characterization to include parcel size, soils, vegetation, hydrology, wildlife, and topography;
c. Complete site characterization of the proposed mitigation site to include parcel size, soils, vegetation, hydrology, topography and wildlife;
d. Goals, objectives, and performance standards of the mitigation proposal;
e. A mitigation implementation schedule that includes the sequence and timelines of tasks to fully implement the mitigation plan;
f. Monitoring and maintenance for a minimum of five consecutive years, and a contingency plan;
g. Function assessment of wetland to be impacted;
h. Delineation report, with maps, of site to be impacted;
i. Map of development, with scale, overlaid on wetland delineation map; and
j. A detailed, line-item estimate of the total costs to complete the approved mitigation plan including, but not limited to, a minimum of five years of monitoring and maintenance, shall be submitted for approval for the required financial surety for the project. The total estimate shall be multiplied by 150 percent. [Ord. 2016-02-005 § 26; Ord. 2005-11-092].