A. 
Activities and uses shall be prohibited from wetlands and wetland buffers, except as provided for in this chapter.
B. 
Unless otherwise allowed by this chapter, activities may only be permitted in a wetland or wetland buffer after demonstration of mitigation sequencing, and if the applicant can show that the proposed activity will not degrade the functions and values of the wetland and other critical areas and no other feasible site design exists that results in less encroachment or impact to the wetland or wetland buffer.
C. 
Category I and II Wetlands. Activities and uses shall be prohibited from Category I and II wetlands, except as provided for in the exemptions, public agency and utility exception, or reasonable use exception sections of this chapter, or in subsection E of this section.
D. 
Category III and IV Wetlands. Activities may be permitted if the city manager determines, based upon review of special studies completed by qualified professionals, that the activity meets avoidance and minimization requirements outlined in KMC § 18.55.210 and will not:
1. 
Adversely affect water quality;
2. 
Adversely affect fish, wildlife, or their habitat;
3. 
Have an adverse effect on drainage and/or stormwater detention capabilities;
4. 
Lead to unstable earth conditions or create an erosion hazard or contribute to scouring actions;
5. 
Be materially detrimental to any other property or the City as a whole; or
6. 
Have adverse effects on any other critical areas.
E. 
Wetland and Buffer Uses. The following uses may be permitted within a wetland and wetland buffer in accordance with the review procedures of this chapter, provided they are not prohibited by any other applicable law, and they are conducted in a manner so as to minimize impacts to the buffer and adjacent wetland:
1. 
Conservation and Restoration Activities. Conservation or restoration activities aimed at protecting or restoring the soil, water, vegetation, or wildlife;
2. 
Passive Recreation. Passive recreation facilities designed in accordance with an approved critical areas report, including:
a. 
Private walkways and trails; provided, that those pathways that are generally parallel to the perimeter of the wetland shall be located in the outer 25 percent of the buffer area. Walkway and trail surfaces in buffers shall be made of pervious materials and shall be a maximum of five feet wide. Where private walkways and trails must cross a wetland to reach a permitted water access structure, such as a dock, or a pedestrian bridge over an associated waterbody, the walkway or trail must be a raised boardwalk supported by piles that allow free movement of water beneath the structure;
b. 
Public walkways and trails; provided, that those pathways are located and designed based on existing site-specific conditions to minimize native vegetation removal and are part of an approved public park or trail plan. The trail proposal shall be accompanied by a plan demonstrating that the existing ecological functions of the wetland or required buffer area on a project site would be improved. Walkways and trails; provided, that they are limited to minor crossings having no adverse impact on water quality. They should be generally parallel to the perimeter of the wetland, located only in the outer 25 percent of the wetland buffer area, and located to avoid removal of significant (as defined in KMC § 18.20.2730), old growth, or mature trees. They should be limited to pervious surfaces and designed for pedestrian use only. Raised boardwalks utilizing nontreated pilings may be acceptable. Walkway and trail surfaces in buffers shall be made of pervious materials except that public multipurpose trails may be of impervious materials if they meet all other requirements, including water quality. Gravel is considered impermeable. Trail segments in wetlands must be a raised boardwalk supported by piles that allow free movement of water beneath the structure but should be limited to protect ecological functions of the buffer and wetland.
c. 
Walkways and trails proposed in wetlands and buffers by private parties as part of subdivisions, multifamily development, or commercial or institutional uses may be allowed, subject to subsection (E)(2)(b) of this section, if they will be accessible to the general public, identified with visible signage, and are recorded on title. Providing connectivity to existing City or regional trail systems or completing or contributing to a trail linkage identified in the City’s Parks, Recreation and Open Space Plan or Walkways and Waterways Plan is encouraged;
d. 
Wildlife viewing structures;
e. 
Fishing access areas; and
f. 
Interpretive and other signs, benches, railings, and similar accessories to passive recreation that do not require significant ground disturbance, vegetation clearing, or concrete foundations;
3. 
Stormwater Management Facilities. Stormwater dispersion outfalls and bioswales may be located in the outer 25 percent of the buffer area of Category III and IV wetlands only. All other surface water management facilities are not allowed within the buffer area.
4. 
Subdivisions. The subdivision and/or short subdivision of land where wetlands and/or associated buffers are present are subject to the following:
a. 
Land that is located wholly within a wetland and/or wetland buffer may not be subdivided;
b. 
Land that is located partially within a wetland and/or wetland buffer may be subdivided; provided, that an accessible and continuous portion of each new lot is:
i. 
Located outside of the wetland and buffer; and
ii. 
Meets the minimum lot size requirements of the zone.
(Ord. 11-0329 § 3 (Exh. 1); Ord. 12-0334 § 14; Ord. 19-0488 § 2 (Exh. 1); Ord. 24-0624 § 5 (Exh. C))
A. 
Buffer Conditions Shall Be Maintained. Except as otherwise specified or allowed in accordance with this chapter, wetland buffers shall be retained in an undisturbed condition.
B. 
Averaged Buffer Widths. The city manager may allow averaging of the wetland buffer width in accordance with an approved critical areas report and the best available science on a case-by-case basis. Averaging of buffer widths may only be allowed where a qualified professional biologist demonstrates that:
1. 
Additional protection to the wetland will be provided through implementation of a buffer enhancement plan;
2. 
It will not reduce wetland functions or values;
3. 
The wetland contains variations in sensitivity due to existing physical characteristics or the character of the buffer varies in slope, soils, or vegetation, and the wetland would benefit from a wider buffer in places and would not be adversely impacted by a narrower buffer in other places;
4. 
The total area contained in the buffer after averaging is no less than that which would be contained within the standard buffer; and
5. 
The buffer width shall not be reduced by more than 25 percent in any one place.
C. 
The City may approve a modification of the minimum required buffer in cases where an improved right-of-way, associated with a legally established roadway, transects the buffer. The buffer may be reduced to match the edge of the right-of-way closest to the wetland if the portion of the buffer on the other side of the roadway meets the following criteria:
1. 
Does not provide additional protection to the proposed development from flooding or other hazard, or to the wetland; and
2. 
Provides insignificant biological, geological or hydrological buffer functions relating to the other portion of the buffer adjacent to the wetland.
Improved rights-of-way are those that are maintained out of necessity as a cleared, graded, paved, mowed or otherwise altered surface to allow for access, maintenance, or safety.
D. 
The City may approve a modification of the minimum required buffer width where the proposed development or use is isolated from the critical area and its contiguous buffer by an existing legally established building, detached garage, accessory dwelling unit, commercial parking area, or retaining wall over six feet in height. The modification may not be requested for such improvements as fences, sheds, patios, decks, driveways, or other similar structures and impervious surfaces.
For the buffer modification to be approved, the applicant must demonstrate conclusively in a critical area report that all of the following criteria are met:
1. 
The existing legal improvement between the proposed development or use and the wetland creates a substantial barrier to buffer function;
2. 
The isolated section of buffer does not provide additional protection of the critical area from the proposed development; and
3. 
The isolated section of buffer does not provide significant hydrological, water quality, and wildlife buffer functions relating to the portion of the buffer adjacent to the critical area.
(Ord. 19-0488 § 2 (Exh. 1))
A. 
Mitigation Shall Achieve Equivalent or Greater Ecological Functions. Mitigation for alterations to wetlands and buffers shall achieve equivalent or greater ecologic functions than exist in the impacted wetland and buffer. Mitigation plans shall be generally consistent with the Department of Ecology Guidelines found in Wetland Mitigation in Washington State – Part 2, Version 1, March 2006, Publication No. 06-060-011b.
B. 
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:
1. 
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 plan or protocol; or
2. 
Out-of-kind replacement will best meet formally identified regional goals, such as replacement of historically diminished wetland types.
C. 
Buffers for Mitigation Shall Be Consistent. When mitigation for a wetland impact includes creation of a new wetland area, the new area shall be provided with a functioning buffer consistent with the buffer requirements of this chapter, unless determined by the city manager through a variance or a reasonable use exemption that a different buffer would provide adequate protection to the critical area.
D. 
Preference of Mitigation Actions. Mitigation sequencing outlined in KMC § 18.55.210 shall be demonstrated in each development proposal. Mitigation actions that require compensation by replacing, enhancing, or substitution shall occur in the following order of preference:
1. 
Restoring wetlands on upland sites that were formerly wetlands.
2. 
Creating wetlands in upland areas, considering degraded areas first.
3. 
Enhancing significantly degraded wetlands.
4. 
Preserving high quality wetlands that are under imminent threat.
E. 
Type and Location of Mitigation. Mitigation actions shall be conducted within the same subdrainage basin or on the same site as the alteration except when all of the following apply:
1. 
There are no reasonable on-site or in-subdrainage-basin opportunities, or on-site and in-subdrainage-basin opportunities do not have a high likelihood of success due to development pressures or adjacent land uses, or on-site buffers or connectivity is inadequate;
2. 
Off-site mitigation has a greater likelihood of providing equal or improved wetland functions than the impacted wetland; and
3. 
Off-site locations shall be in the same subdrainage basin unless 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.
F. 
Mitigation Timing. Where feasible, mitigation or restoration projects shall be completed prior to activities that will disturb wetlands. In all other cases, mitigation shall be completed immediately following disturbance and prior to use or occupancy of the activity or development. Construction of mitigation projects shall be timed to reduce impacts to existing wildlife and flora.
G. 
Mitigation Ratios.
1. 
Acreage Replacement Ratios. The following ratios shall apply to creation or restoration that is in kind, on site, the same category, timed prior to or concurrent with alteration, and has a high probability of success. These ratios do not apply to remedial actions resulting from unauthorized alterations; greater ratios shall apply on a case-by-case basis. These ratios do not apply to the use of credits from a State-certified wetland mitigation bank. The first number specifies the acreage of replacement wetlands and the second specifies the acreage of wetlands altered.
Standard Wetland Mitigation Ratios
Category and Type of Wetland
Creation or Reestablishment
Rehabilitation1
Enhancement2
Category I (Mature Forested)
6:1
12:1
24:1
Category I
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
Buffer
1:1
1:1
1:1
Notes:
1
“Rehabilitation” means the manipulation of the physical, chemical, or biological characteristics of a site with the goal of repairing natural or historic functions and processes of a degraded wetland. Rehabilitation results in a gain in wetland function but does not result in a gain in wetland acres. An example would be breaching a dike to reconnect wetlands to a floodplain.
2
“Enhancement” means the manipulation of the physical, chemical, or biological characteristics of a wetland to heighten, intensify, or improve specific function(s) or to change the growth stage or composition of the vegetation present. Enhancement is undertaken for specified purposes such as water quality improvement, floodwater retention, or wildlife habitat. Enhancement results in a change in wetland function(s) and can lead to a decline in other wetland functions, but does not result in a gain in wetland acres. Examples are planting vegetation, controlling nonnative or invasive species, and modifying site elevations to alter hydroperiods.
2. 
Increased Replacement Ratio. The city manager may increase the ratios under the following circumstances:
a. 
Uncertainty exists as to the probable success of the proposed restoration or creation; or
b. 
A significant period of time will elapse between impact and replication of wetland functions; or
c. 
Mitigation will occur off site versus on site; or
d. 
Proposed mitigation will result in a lower category wetland or reduced functions relative to the wetland being impacted; or
e. 
The impact was an unauthorized impact.
3. 
Decreased Replacement Ratio.
a. 
The city manager may decrease the creation/reestablishment ratios required for Category II and III wetlands to 2:1 and 1.5:1, respectively, under the following circumstances:
(1) 
The applicant’s qualified biologist provides documentation that increases the certainty of success of the proposed wetland restoration or creation. At a minimum, this documentation shall include groundwater monitoring in the area of proposed restoration or creation in the early growing season over a sufficient period of time to determine that there is a high probability of creating or restoring wetlands in that location; or
(2) 
Proposed mitigation will result in a higher functioning wetland (higher class) relative to the functions of the wetland being impacted; or
(3) 
The mitigation is successfully installed for a period of one year prior to the wetland being impacted. Successful installation shall be determined by a qualified biologist.
b. 
When a decreased replacement ratio is allowed, the mitigation shall be monitored for a period of no less than 10 years.
4. 
Credit/Debit Method. As an alternative to the standard mitigation ratios, the City may allow mitigation based on the “credit/debit” method developed by the Department of Ecology and documented in Calculating Credits and Debits for Compensatory Mitigation in Wetlands of Western Washington, Final Report, March 2012 (Hruby, 2012, or as revised).
H. 
Wetlands Enhancement as Mitigation. Impacts to wetlands may be mitigated by enhancement of existing significantly degraded wetlands. Applicants proposing to enhance wetlands must produce a critical areas report that identifies how enhancement will increase the functions of the degraded wetland and how this increase will adequately mitigate for the loss of wetland area and function at the impact site. An enhancement proposal must also show whether existing wetland functions will be reduced by the enhancement actions.
I. 
Mitigation Banking.
1. 
Credits from a wetland mitigation bank may be approved for use as compensation for unavoidable impacts to wetlands when:
a. 
The bank is certified under State rules;
b. 
The city manager 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 certified bank instrument.
2. 
Replacement ratios for projects using bank credits shall be consistent with replacement ratios specified in the certified bank instrument.
3. 
Credits from a certified wetland mitigation bank may be used to compensate for impacts located within the service area specified in the certified bank instrument. In some cases, the service area of the bank may include portions of more than one adjacent drainage basin for specific wetland functions.
J. 
In-Lieu Fee Programs. To aid in the implementation of off-site mitigation, the City may develop an in-lieu fee (ILF) program or allow participation in an ILF program, such as King County’s mitigation reserves program. ILF programs shall be developed and approved through a public process and be consistent with federal rules, State policy on in-lieu fee mitigation, and State water quality regulations. An approved ILF program sells compensatory mitigation credits to permittees whose obligation to provide compensatory mitigation is then transferred to the in-lieu program sponsor, a governmental or nonprofit natural resource management entity. Credits from an approved in-lieu fee program may be used when subsections (J)(1) through (6) of this section apply:
1. 
The city manager determines that it would provide environmentally appropriate compensation for the proposed impacts.
2. 
The mitigation will occur on a site identified using the site selection and prioritization process in the approved ILF program instrument.
3. 
The proposed use of credits is consistent with the terms and conditions of the approved ILF program instrument.
4. 
Land acquisition and initial physical and biological improvements of the mitigation site must be completed within three years of the credit sale. A one-year extension to this requirement may be granted by the city manager if the need for additional mitigation because of possible temporal loss is evaluated and addressed.
5. 
Projects using ILF credits shall have debits associated with the proposed impacts calculated by the applicant’s qualified wetland scientist using the method consistent with the credit assessment method specified in the approved instrument for the ILF program.
6. 
Credits from an approved ILF program may be used to compensate for impacts located within the service area specified in the approved ILF instrument.
K. 
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.
L. 
Alternative Mitigation Plans. The city manager may approve alternative critical areas mitigation plans that are based on best available science, such as priority restoration plans that achieve restoration goals identified in the Shoreline Master Program (SMP). Alternative mitigation proposals must provide an equivalent or better level of protection of critical area functions and values than would be provided by the strict application of this chapter and must contain all of the standard components of a mitigation plan. The city manager shall consider the following for approval of an alternative mitigation proposal:
1. 
The proposal uses a watershed approach consistent with Selecting Wetland Mitigation Sites Using a Watershed Approach (Western Washington) (Ecology Publication No. 09-06-32, Olympia, WA, December 2009, or as revised).
2. 
Creation or enhancement of a larger system of natural areas and open space is preferable to the preservation of many individual habitat areas.
3. 
There is clear potential for success of the proposed mitigation at the proposed mitigation site.
4. 
A wetland of a different type is justified based on regional needs or functions and values; the replacement ratios may not be reduced or eliminated unless the reduction results in a preferred environmental alternative.
(Ord. 11-0329 § 3 (Exh. 1); Ord. 12-0334 §§ 15, 16; Ord. 19-0488 § 2 (Exh. 1))