A. 
Identification and Delineation. Identification of wetlands and delineation of their boundaries must be done in accordance with the 1987 Corps of Engineers Wetland Delineation Manual (Publication No. Y-87-1) and the Western Mountains, Valleys, and Coast Regional Supplement (Publication No. ERDC/EL TR-10-3). Wetland delineations are valid for five years, after which the director shall determine whether a revision or additional assessment is necessary. All areas within the city meeting the criteria in the approved federal wetland delineation manual and regional supplement, regardless of any formal identification, are hereby designated critical areas and shall be subject to the provisions of this chapter.
B. 
Mapping. The approximate location and extent of known or suspected wetlands are shown on the city’s adopted critical area maps as contained within the environmental element of the comprehensive plan. These maps shall be used as a guide for the city, applicants and/or property owners, and may be updated as new wetlands are identified. The exact location of a wetland boundary shall be determined through field investigation by a qualified professional applying the approved federal wetland delineation manual and regional supplement methods and procedures.
C. 
Rating. Wetlands shall be rated and regulated according to the categories defined by the Washington State Wetland Rating System for Western Washington: 2014 Update, Version 2.0 (Publication No. 23-06-009, or as revised). Wetland ratings are valid for five years, after which the director shall determine whether a revision or additional rating is necessary.
D. 
Illegal Modifications. Wetland rating categories will not change due to illegal modifications made to the wetland.
E. 
Wetlands that meet the following criteria are not subject to the avoidance or minimization requirements of the mitigation sequence (consistent with MCMC § 18.06.610) in accordance with the following provisions, and they may be filled if the impacts are fully mitigated based on the actions in MCMC § 18.06.610. Impacts should be mitigated through the purchase of credits from an in-lieu fee program or mitigation bank, if available, consistent with the terms and conditions of the program or bank. In order to verify whether the following criteria are met, it is essential that a critical area report for wetlands meeting the requirements in MCMC § 18.06.950 be submitted.
1. 
All Category IV wetlands less than 4,000 square feet that:
a. 
Are located in the areas covered by the Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Western Mountains, Valleys, and Coast Region;
b. 
Are not associated with riparian areas or their buffers;
c. 
Are not associated with shorelines of the state or their associated buffers;
d. 
Are not part of a wetland mosaic;
e. 
Do not score six or more points for habitat function based on the Washington State Wetland Rating System for Western Washington: 2014 Update, Version 2.0 (Ecology Publication No. 23-06-009), or as revised and approved by Ecology; and
f. 
Do not contain a priority habitat or a priority area for a priority species identified by the Washington Department of Fish and Wildlife and do not contain state or federally listed species or their critical habitat or species of local importance.
2. 
Wetlands less than 1,000 square feet that meet the above criteria are exempt from the buffer provisions contained in this chapter.
(Ord. 2004-603 § 2; Ord. 2009-702 § 2 (Exh. C); Ord. 2015-796 § 3; Ord. 2022-879 § 2; Ord. 2026-945 § 2 (Att. A))
A. 
All activities and uses shall be prohibited in wetlands and wetland buffers except as expressly provided for in this chapter. All feasible and reasonable measures shall be taken to avoid and minimize impacts to wetlands. These actions may include consideration of alternative site plans and layouts, reductions in the density or scope of the proposal, and implementation of the performance standards contained in this chapter. Alteration of wetlands shall be permitted only in accordance with an approved critical area report and mitigation plan. The burden of proof shall be on the applicant.
B. 
All significant adverse impacts to wetland functions and values and to associated buffers shall be avoided. Where such impacts cannot be avoided, the applicant shall implement appropriate compensatory mitigation according to the provisions of MCMC § 18.06.610 and 18.06.960.
C. 
Alteration of Category I wetlands is prohibited.
D. 
Alteration of Category II, III, and IV wetlands may be permitted in accordance with an approved critical area report and mitigation plan, and only when the applicant demonstrates that:
1. 
The basic project purpose cannot reasonably be accomplished without the wetland alteration; and
2. 
There are no reasonable or practical alternatives to the alteration, including without limitation on-site design or acquisition of additional area.
(Ord. 2004-603 § 2; Ord. 2026-945 § 2 (Att. A))
A. 
Standard Buffer Width. The standard buffer widths in Table 18.06.930-1 have been established in accordance with the best available science. They are based on the category of wetland and the habitat score as determined in accordance with MCMC § 18.06.910. The following provisions apply to the use and measurement of standard wetland buffer widths:
1. 
Measurement. All buffers must be measured perpendicular from the wetland boundary as delineated in the field.
2. 
Habitat Corridors. A habitat corridor is required for all wetlands with a habitat score of six or more unless no suitable areas – defined in MCMC § 18.06.210 – exist on or adjacent to the project site for a habitat corridor to connect to. If a habitat corridor is required, but not provided, the alternative buffer widths in Table 18.06.930-3 apply.
3. 
Impact Minimization Measures. Implementation of as many impact minimization measures from Table 18.06.930-2 as practicable is required. The director, in coordination with the applicant, will determine which measures are applicable and feasible. If impact minimization measures are not implemented, the alternative buffer widths in Table 18.06.930-3 apply.
4. 
Vegetation. Required buffer widths assume that the buffer is vegetated with a native plant community. If the existing buffer is unvegetated, sparsely vegetated, or vegetated with invasive species that do not perform needed functions, the buffer must either be planted to create the appropriate native plant community or be widened to ensure that the buffer provides adequate functions to protect the wetland.
Table 18.06.930-1 Standard Wetland Buffer Requirements
Category of Wetland
Buffer Width in Feet
Habitat Score: 3 – 5
Habitat Score: 6 – 7
Habitat Score: 8 – 9
Category I: Bogs and Wetlands of High Conservation Value
190
190
225
Category I: Forested
75
110
Category I or II: No Special Characteristics
Category III: All types
60
Category IV: All types
40
40
40
Table 18.06.930-2 Impact Minimization Measures
Disturbance
Activities and Uses That Cause Disturbances
Examples of Measures to Minimize Impacts
Lights
• Parking lots
• Commercial/industrial
• Residential
• Recreation (e.g., athletic fields)
• Agricultural buildings
• Direct lights away from wetland
• Only use lighting where necessary for public safety and keep lights off when not needed
• Use motion-activated lights
• Use full cut-off filters to cover light bulbs and direct light only where needed
• Limit use of blue-white colored lights in favor of red-amber hues
• Use lower-intensity LED lighting
• Dim light to the lowest acceptable intensity
Noise
• Commercial
• Industrial
• Recreation (e.g., athletic fields, bleachers, etc.)
• Residential
• Agriculture
• Locate activity that generates noise away from wetland
• Construct a fence to reduce noise impacts on adjacent wetland and buffer
• Plant a strip of dense shrub vegetation adjacent to wetland buffer
Toxic Runoff
• Parking lots
• Roads
• Commercial/industrial
• Residential areas
• Application of pesticides
• Landscaping
• Agriculture
• Route all new, untreated runoff away from wetland while ensuring wetland is not dewatered
• Establish covenants limiting use of pesticides within 150 ft. of wetland
• Apply integrated pest management
(These examples are not necessarily adequate for minimizing toxic runoff if threatened or endangered species are present at the site.)
Stormwater Runoff
• Parking lots
• Roads
• Residential areas
• Commercial/industrial
• Recreation
• Landscaping/lawns
• Other impermeable surfaces, compacted soil, etc.
• Retrofit stormwater detention and treatment for roads and existing adjacent development
• Prevent channelized or sheet flow from lawns that directly enters the buffer
• Infiltrate or treat, detain, and disperse new runoff from impervious surfaces and lawns
Pets and human disturbance
• Residential areas
• Recreation
• Use privacy fencing
• Plant dense native vegetation to delineate buffer edge and to discourage disturbance
• Place wetland and its buffer in a separate tract
• Place signs around the wetland buffer every 50-200 ft., and for subdivisions place signs at the back of each residential lot
• When platting new subdivisions, locate green-belts, stormwater facilities, and other lower-intensity land uses adjacent to wetland buffers
Dust
• Tilled fields
• Roads
• Use best management practices to control dust
Table 18.06.930-3 Alternative Wetland Buffer Requirements
Category of Wetland
Buffer Width in Feet
Habitat Score: 3 – 5
Habitat Score: 6 – 7
Habitat Score: 8 – 9
Category I: Bogs and Wetlands of High Conservation Value
250
250
300
Category I: Forested
100
150
Category I or II: No Special Characteristics
Category III: All types
80
Category IV: All types
50
50
50
B. 
Increased Buffer Width. Buffer widths may be increased on a case-by-case basis as determined by the director when a wider buffer is necessary to protect wetland functions and values. This determination must be supported by appropriate documentation showing that it is reasonably related to protection of the functions and values of the wet-land. The documentation must include but not be limited to the following criteria:
1. 
The wetland is used by a priority species or has a priority habitat area;
2. 
The adjacent land is susceptible to severe erosion, and erosion-control measures will not effectively prevent adverse wetland impacts;
3. 
The adjacent land has minimal vegetative cover; or
4. 
The land has slopes greater than 30 percent.
C. 
Reduced or Averaged Buffer Width. The director has the authority to reduce or average required buffers in the following circumstances, except that a buffer at its narrowest point must never be less than either 75 percent of the required width or 75 feet for Category I and II, 50 feet for Category III, and 25 feet for Category IV, whichever is greater:
1. 
Low Impact Land Uses. The required buffer width may be reduced by up to 25 percent if the proposed land use has a low level of impact.
2. 
Wetland Protection. Buffer averaging to improve wetland protection may be permitted when all of the following conditions are met:
a. 
The wetland has significant differences in characteristics that affect its habitat functions, such as a wetland with a forested component adjacent to a degraded emergent component or a dual-rated wetland with a Category I area adjacent to a lower-rated area.
b. 
The buffer is increased adjacent to the higher-functioning area of habitat or more sensitive portion of the wetland and decreased adjacent to the lower-functioning or less sensitive portion.
c. 
The total area of the buffer after averaging is equal to the area required without averaging.
3. 
Reasonable Use. Averaging to allow reasonable use of a parcel may be permitted when all of the following are met:
a. 
No feasible alternatives to the site design could be accomplished without buffer averaging.
b. 
The averaged buffer will not result in degradation of the wetland’s functions and values as demonstrated by a critical area report from a qualified professional.
c. 
The total buffer area after averaging is equal to the area required without averaging.
D. 
The edge of the buffer area shall be clearly staked, flagged, and fenced prior to any site clearing and construction. The buffer boundary markers shall be clearly visible, durable, and permanently affixed to the ground. Site clearing shall not commence until the applicant has submitted written notice to the department that buffer requirements of this chapter are met. Field marking shall remain until all construction and clearing phases are completed, and final approval has been granted by the city.
E. 
Structures shall be set back in accordance with MCMC § 18.06.840 such that construction activities and outdoor living areas do not infringe upon the required buffer edge.
F. 
Impervious surfaces shall not be constructed in wetland buffers except as expressly provided for in this chapter.
(Ord. 2004-603 § 2; Ord. 2022-879 § 2; Ord. 2026-945 § 2 (Att. A))
Wetland buffers shall be retained in an undisturbed condition except that the following uses may be permitted within a wetland buffer when the applicant demonstrates to the satisfaction of the director that no net loss of wetland functions and values will occur:
A. 
Public and private roadway crossings, including bridge construction and culvert installation in or across wetland buffers may be allowed, if the director determines that such construction is necessary and cannot be accomplished in another location.
B. 
Stormwater management facilities, limited to outfall facilities (level spreaders, infiltration trenches) may be allowed within the outer 50 percent of the standard buffer of a wetland; provided, that all of the following criteria are met:
1. 
Construction of the stormwater facility does not impact mature forest vegetation;
2. 
There is no other feasible location for the stormwater facility;
3. 
The stormwater facility is designed according to city standards and the discharge water meets state water quality standards;
4. 
Construction of stormwater management facilities in the buffer of a Category I wetland is prohibited;
5. 
Stormwater conveyance or discharge facilities such as dispersion trenches, level spreaders, and outfalls may encroach into the inner 50 percent of a Category II, III or IV wetland buffer on a case-by-case basis when the director and city engineer determine that due to topographic or other physical constraints there are no feasible locations for these facilities in the outer buffer area; and
6. 
Altered areas are mitigated per MCMC § 18.06.610 and 18.06.960.
C. 
Conservation or restoration activities aimed at protecting the soil, water, vegetation, or wildlife may be allowed.
D. 
Passive recreation facilities, including walkways, wildlife viewing structures, and trails, that are part of an interpretive trail system or environmental education program, may be allowed if they are designed in accordance with an approved critical area report; and provided, that they are located in the outer 50 percent of the buffer area where possible and practical and are constructed in such a manner to avoid disturbance of sensitive wildlife, feeding, roosting, breeding, or rearing sites, and meet the requirements of MCMC § 18.06.410(A)(4).
(Ord. 2004-603 § 2; Ord. 2026-945 § 2 (Att. A))
A. 
A critical area report for wetlands shall contain site- and proposal-specific information consistent with MCMC § 18.06.530 and shall at a minimum contain the following additional information:
1. 
A written assessment and accompanying maps of the wetlands and buffers within 300 feet of the site and an estimate of the existing acreage for each wetland;
2. 
A detailed description of the effects of the proposed development on wetland and buffer area, values and function, including quantification of the area of wetland disturbance;
3. 
Vegetation, soil, hydrologic, and topographic characteristics of all on-site wetlands and buffers. This includes the dominant species; soil type, color and texture; sources of hydrology (surface inflow, hyporheic flows, precipitation, etc.).
B. 
The director shall have the authority to require the critical area report to include an evaluation by the Department of Ecology.
(Ord. 2004-603 § 2)
A. 
All significant adverse impacts to wetlands and buffers as determined by the director shall be fully mitigated in accordance with the standards set forth in MCMC § 18.06.610 and this section. All mitigation shall be specified in a mitigation plan consistent with MCMC § 18.06.620 and this section. Mitigation measures addressed in the mitigation plan must comply with the mitigation sequencing requirements of MCMC § 18.06.625.
B. 
Requirements for Compensatory Mitigation.
1. 
Compensatory mitigation for alterations to wetlands may be used only for impacts that cannot be avoided or minimized and must achieve equivalent or greater functions.
2. 
Mitigation ratios, if used, must be consistent with MCMC § 18.06.970.
3. 
Plantings used in mitigation actions must be native species appropriate to the ecoregion.
4. 
The following areas within a proposed compensation site do not contribute to satisfying the requirements for compensatory mitigation:
a. 
Easements for utility corridors, stormwater facilities, rights-of-way, and streams conveyed underground;
b. 
Any paved or graveled areas intended to convey vehicle or foot traffic.
5. 
All wetland mitigation sites must have buffers consistent with MCMC § 18.06.930.
C. 
Compensation for Lost or Affected Functions. Compensation in the form of wetland creation, restoration or enhancement is required when a wetland is altered permanently as a result of an approved project. Alterations shall not result in net loss of wetland area except when the following criteria are met:
1. 
The lost wetland area provides minimal functions as determined by a function assessment and the mitigation action(s) results in a net gain in wetland functions as determined by a site-specific function assessment; or
2. 
The lost wetland area provides minimal functions as determined by a function assessment and other replacement habitats provide greater benefits to the functioning of the watershed, such as riparian habitat restoration and enhancement.
D. 
Approaches to Compensatory Mitigation. Mitigation for lost or diminished wetland and buffer functions must rely on the approaches listed below:
1. 
Wetland Mitigation Banks. Credits from a wetland mitigation bank certified under Chapter 173-700 WAC may be used to compensate for impacts located within the service area specified in the mitigation bank instrument if all the following are met:
a. 
The director determines that it would provide appropriate compensation for the proposed impacts;
b. 
The proposed use of credits is consistent with the terms and conditions of the mitigation bank instrument; and
c. 
Mitigation ratios are consistent with ratios specified in the mitigation bank instrument.
2. 
In-Lieu Fee (ILF) Mitigation. Credits from an approved in-lieu fee program may be used when all the following apply:
a. 
The director determines that it would provide appropriate compensation for the proposed impacts;
b. 
The proposed use of credits is consistent with the terms and conditions of the approved ILF program instrument;
c. 
Projects using ILF credits have debits associated with the proposed impacts calculated by the applicant’s qualified professional using the credit assessment method specified in the approved instrument for the ILF program; and
d. 
The impacts are located within the service area specified in the approved ILF instrument.
3. 
Permittee-Responsible Advance Mitigation. Advance mitigation is a form of permittee-responsible mitigation implemented before a permitted impact takes place. It is designed to compensate for impacts expected to occur in the future. The applicant proposing the advance mitigation is the only one who can use the credits generated. Credits cannot be sold or transferred to another applicant. Advance mitigation proposals should be developed in accordance with state and federal rules and guidance on advance mitigation consistent with Interagency Regulatory Guide: Advance Permittee-Responsible Mitigation (Publication No. 12-06-015, or as revised) and Chapter 4.2 of Wetland Mitigation in Washington State – Part 1: Policies and Guidance, Version 2 (Publication No. 21-06-003, or as revised).
4. 
Permittee-Responsible Concurrent Mitigation. Concurrent mitigation is a form of permit-tee-responsible mitigation implemented at the same time permitted impacts are occurring. The permittee is responsible for implementation and success of the compensation. Concurrent mitigation may occur at the site of the permitted impacts or at an off-site location, usually within the same watershed. Permittee-responsible concurrent mitigation may be used only if the applicant’s qualified professional demonstrates to the director’s satisfaction that the proposed approach is ecologically preferable to use of a bank or ILF program.
E. 
Methods of Compensatory Mitigation. Mitigation for wetland and buffer impacts must use one of the methods listed below, in order of preference, as defined in MCMC § 18.06.210. A lower-preference method of mitigation may be used only if the applicant’s qualified professional demonstrates to the director’s satisfaction that all higher-ranked types of mitigation are not feasible.
1. 
Restoration. Restoration is divided into two categories: re-establishment and rehabilitation.
2. 
Creation. If a site is not available for wetland restoration to compensate for expected wetland or buffer impacts, the director may authorize creation of a wetland and buffer upon demonstration by the applicant’s qualified professional that:
a. 
The hydrology and soil conditions at the proposed mitigation site are conducive for sustaining the proposed wetland and that creation of a wetland at the site will not likely cause hydrologic problems elsewhere;
b. 
Adjacent land uses and site conditions do not jeopardize the viability of the proposed wetland and buffer (e.g., due to the presence of invasive plants or noxious weeds, stormwater runoff, noise, light, or other impacts);
c. 
The proposed wetland and buffer will eventually be self-sustaining with little or no longterm maintenance; and
d. 
The proposed wetland would not be established at the cost of another high-functioning habitat (i.e., ecologically important uplands).
3. 
Preservation. Preservation of a wetland and associated buffer may be used only if:
a. 
The director determines that the proposed preservation is the best available mitigation option;
b. 
The proposed preservation site is under threat of undesirable ecological change due to permitted, planned, or likely actions that will not be adequately mitigated under existing regulations;
c. 
Permanent preservation of the wetland and buffer is ensured through a legal mechanism, such as a conservation easement or a critical area tract established consistent with MCMC § 18.06.830; and
d. 
The area proposed for preservation is of high quality or critical for the health and ecological sustainability of the watershed or subbasin. Characteristics indicative of high-quality sites include:
i. 
Category I or II wetland rating per MCMC § 18.06.910(C);
ii. 
Rare or irreplaceable wetland type such as peatlands, mature forested wetlands, vernal pools or alkali wetlands;
iii. 
Aquatic habitat that is rare or a limited resource in the area;
iv. 
The presence of priority habitat;
v. 
Biological or hydrological connectivity to other habitats; and
vi. 
Priority sites identified in an adopted watershed plan.
4. 
Enhancement. Applicants proposing to enhance wetlands or buffers shall demonstrate how the proposed enhancement will increase the wetland or buffer functions, how this increase in function will adequately compensate for the impacts, and how existing wetland functions at the mitigation site will be protected.
5. 
Alternative Types of Mitigation. The director may approve alternative mitigation proposals that are based on best available science. Alternative mitigation proposals must provide an equivalent or better level of ecological functions and values than would be provided by standard mitigation approaches. Alternative mitigation approaches must comply with all reporting, monitoring, and performance measures of this chapter including adherence to mitigation sequencing. The city may consult with agencies with expertise and jurisdiction over the critical areas during the review to assist with analysis and identification of appropriate performance measures that adequately safeguard critical areas.
The director will consider the following for approval of an alternative mitigation proposal:
a. 
Clear identification of how an alternative approach will achieve equal or better ecological benefit;
b. 
Use of a watershed approach consistent with Selecting Wetland Mitigation Sites Using a Watershed Approach (Publication No. 09-06-32, or as revised);
c. 
Identification, evaluation, and mitigation of all impacts; and
d. 
Clear and measurable methods to demonstrate ecological success.
F. 
Location of Compensatory Mitigation. Permittee-responsible compensatory mitigation actions must be conducted using a watershed approach and must generally occur within the same subdrainage basin. However, when the applicant can demonstrate that a mitigation site in a different subdrainage basin is ecologically preferable, it should be used.
1. 
The following criteria must be evaluated when determining whether on-site or off-site compensatory mitigation is ecologically preferable. When considering the location of mitigation, preference should be given to using programmatic approaches, such as a mitigation bank or an ILF program.
a. 
No reasonable opportunities exist on site or within the subdrainage basin or opportunities on site or within the subdrainage basin do not have a high likelihood of success based on a determination of the capability of the site to compensate for the impacts. Considerations should include:
i. 
Anticipated replacement ratios for wetland mitigation;
ii. 
Buffer conditions and required widths;
iii. 
Available water to maintain anticipated hydrogeomorphic classes of wetlands when restored;
iv. 
Proposed flood storage capacity; and
v. 
Potential to mitigate riparian fish and wildlife impacts.
b. 
On-site mitigation would require elimination of high-quality upland habitat.
c. 
Off-site mitigation has a greater likelihood of providing equal or improved wetland functions compared to the altered wetland.
2. 
Off-site locations must be in the same subdrainage basin unless:
a. 
Watershed goals for water quality, flood storage or conveyance, habitat, or other wetland functions have been established by the city and strongly justify locating mitigation at another site;
b. 
Credits from a state-certified wetland mitigation bank are used as compensation, and the use of credits is consistent with the terms of the certified bank instrument; or
c. 
Fees are paid to an approved ILF program to compensate for the impacts.
3. 
The design for the compensatory mitigation project needs to be appropriate for its position in the landscape. Therefore, compensatory mitigation should not result in the creation, restoration, or enhancement of an atypical wetland.
G. 
Timing of Compensatory Mitigation. Where feasible, mitigation 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 vegetation.
H. 
Mitigation Plan. The applicant shall develop a mitigation plan that provides for construction, maintenance, monitoring, contingencies and adaptive management of the wetland compensation projects as required by conditions of approval and consistent with the requirements of this chapter. The mitigation plan shall be consistent with MCMC § 18.06.620.
(Ord. 2004-603 § 2; Ord. 2015-803 § 5 (Exh. A); Ord. 2026-945 § 2 (Att. A))
A. 
Standard Mitigation Ratios. The mitigation ratios for compensatory mitigation must be consistent with Table 18.06.970-1, except where other ratios are required or authorized by this section. Ratios in the table are expressed as the ratio of mitigation area to impact area.
Table 18.06.970-1 Standard Wetland Mitigation Ratios
Category and Type of Wetland
Creation or Re-Establishment
Rehabilitation
Preservation or Enhancement
Category I: Bogs and Wetlands of High Conservation Value
Case-by-case
Case-by-case
Preservation: 24:1 Enhancement: Case-by-case
Category I: Forested
6:1
12:1
24:1
Category I: No Special Characteristics
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
16:1
B. 
Mitigation Bank Ratios. Mitigation ratios for wetland mitigation must be consistent with ratios specified in the mitigation bank instrument.
C. 
Buffer Mitigation Ratios. Impacts to buffers must be mitigated at a minimum 1:1 ratio. Compensatory buffer mitigation must replace those buffer functions lost from development.
D. 
Decreased Mitigation Ratios. Mitigation ratios may be decreased in the following situations:
1. 
Ratios for rehabilitation, preservation, and enhancement may be reduced when combined with 1:1 replacement through re-establishment or creation. See Table 6B-2 in Wetland Mitigation in Washington State – Part 1: Agency Policies and Guidance, Version 2 (Publication No. 21-06-003, or as revised).
2. 
Replacement ratios may be decreased by up to 25 percent by the director if the applicant demonstrates to the satisfaction of the director that all of the following criteria are met:
a. 
Documentation by a qualified professional demonstrates that the proposed mitigation actions have a very high likelihood of success;
b. 
Documentation by a qualified professional demonstrates that the proposed mitigation actions will provide functions and values that are significantly greater than the wetland being altered; and
c. 
The proposed mitigation actions are conducted in advance of the impact and shown to be successful through post-construction monitoring and function assessment.
E. 
Increased Mitigation Ratios. The director shall increase replacement 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; or
3. 
Proposed mitigation will result in a lower category wetland or reduced functions relative to the wetland being impacted; or
4. 
The impact was an unauthorized impact.
F. 
Credit-Debit Method. At the director’s discretion, applicants may be allowed to use an alternative to the mitigation ratios contained in Table 18.06.970-1 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).
(Ord. 2004-603 § 2; Ord. 2015-796 § 4; Ord. 2026-945 § 2 (Att. A))