Chapter 18.20
WETLANDS

Sections:

Article I. Designation, Rating and Mapping

18.20.010    Designation, rating and mapping wetlands.

Article II. Allowed Activities – Wetlands

18.20.020    Activities allowed in wetlands.

Article III. Additional Report Requirements – Wetlands

18.20.030    Critical area report – Additional requirements for wetlands.

Article IV. Performance Standards – Wetlands

18.20.040    Performance standards – General requirements.

18.20.050    Performance standards – Mitigation requirements.

Article I. Designation, Rating and Mapping

18.20.010 Designation, rating and mapping wetlands.

A. Designating Wetlands. Identification of wetlands and delineation of their boundaries pursuant to this chapter shall be done in accordance with the approved federal wetland delineation manual and applicable regional supplements. All areas within the city meeting the wetland designation criteria in that procedure are hereby designated critical areas and are subject to the provisions of this chapter.

B. Wetland Ratings. Wetlands shall be rated in accordance with the Washington State Wetland Rating System for Western Washington (Revised, Publication No. 14-06-029, October 2014) as revised by the Washington State Department of Ecology. This document contains the definitions and methods for determining if the criteria below are met.

1. Wetland Rating Categories.

a. Category I. Category I wetlands are:

i. Wetlands of high conservation value that are identified by scientists of the Washington Natural Heritage Program/DNR as high-quality wetlands.

ii. Bogs.

iii. Mature and old-growth forested wetlands larger than one acre.

iv. Wetlands that perform functions at high levels (scoring twenty-three points or more).

These wetlands: (1) represent unique or rare wetlands; (2) are more sensitive to disturbance than most wetlands; (3) are relatively undisturbed and contain ecological attributes that are impossible to replace within a human lifetime; (4) provide a high level of functions.

b. Category II. Category II wetlands are:

i. Wetlands that perform functions well (scoring between twenty and twenty-two points).

c. Category III. Category III wetlands are:

i. Wetlands with a moderate level of functions (scoring between sixteen and nineteen points).

Wetlands scoring between sixteen and nineteen points generally have been disturbed in some ways and are often less diverse or more isolated from other natural resources in the landscape than Category II wetlands.

d. Category IV. Category IV wetlands have the lowest levels of functions (scoring fewer than sixteen points) and are often heavily disturbed. These are wetlands that are capable of being replaced, or in some cases improved. These wetlands may provide some important functions, and need be protected. (Ord. 426.A § 1 (Exh. A) (part), 2016: Ord. 426 § 1 (Exh. A) (part), 2015: Ord. 389 § 1 (Exh. A) (part), 2011)

Article II. Allowed Activities – Wetlands

18.20.020 Activities allowed in wetlands.

The activities listed below are allowed in wetlands and do not require submission of a critical area report, except where such activities result in a loss to the functions and values of a wetland or wetland buffer. These activities include:

A. Conservation or preservation of soil, water, vegetation, fish, shellfish, and other wildlife that does not entail changing the structure or functions of the existing wetland.

B. The harvesting of wild crops in a manner that is not injurious to natural reproduction of such crops and provided the harvesting does not require tilling of soil, planting of crops, or alteration of the wetland by changing existing topography, water conditions or water sources. (Ord. 426.A § 1 (Exh. A) (part), 2016: Ord. 426 § 1 (Exh. A) (part), 2015: Ord. 389 § 1 (Exh. A) (part), 2011)

Article III. Additional Report Requirements – Wetlands

18.20.030 Critical area report – Additional requirements for wetlands.

In addition to the general critical area report requirements of BMC 18.10.160, critical area reports for wetlands must meet the requirements of this section.

A. Wetland Analysis. A critical area report for wetlands shall contain an analysis of the wetlands including the following site- and proposal-related information at a minimum:

1. A written assessment and accompanying maps of the wetlands and buffers within three hundred feet of the project area, including the following information at a minimum:

a. Wetland delineation and required buffers;

b. Existing wetland acreage;

c. Wetland category; vegetative, faunal, and hydrologic characteristics;

d. Soil and substrate conditions; and

e. Topographic elevations, at two-foot contours.

2. A discussion of measures, including avoidance, minimization and mitigation, proposed to preserve existing wetlands and restore any wetlands that were degraded prior to the current proposed land use activity.

3. A habitat and native vegetation conservation strategy that addresses methods to protect and enhance on-site habitat and wetland functions.

4. Proposed mitigation, if needed, including a written assessment and accompanying maps of the mitigation area, including the following information at a minimum:

a. Existing and proposed wetland acreage.

b. Vegetative, faunal, and hydrologic conditions.

c. Relationship within watershed and to existing water bodies.

d. Soil and substrate conditions, topographic elevations.

e. Existing and proposed adjacent site conditions.

f. Required wetland buffers.

g. Property ownership.

5. A discussion of ongoing management practices that will protect wetlands after the project site has been developed, including proposed monitoring and maintenance programs.

B. Additional Information May Be Required. When appropriate, the director may also require the critical area report to include an evaluation by the Department of Ecology or an independent qualified expert regarding the applicant’s analysis and the effectiveness of any proposed mitigating measures or programs, and to include any recommendations as appropriate. (Ord. 426.A § 1 (Exh. A) (part), 2016: Ord. 426 § 1 (Exh. A) (part), 2015: Ord. 389 § 1 (Exh. A) (part), 2011)

Article IV. Performance Standards – Wetlands

18.20.040 Performance standards – General requirements.

A. Activities may only be permitted in a wetland or wetland buffer if the applicant can show that the proposed activity will not degrade the functions and values of the wetland and other critical areas.

B. Activities and uses shall be prohibited from wetlands and wetland buffers, except as provided for in this title.

C. Category I Wetlands. Activities and uses shall be prohibited from Category I, except as provided for in the public agency utility exception, reasonable use exception, and variance sections of this title.

D. Category II and III Wetlands. The following activities are allowed in Category II and III wetlands:

1. Water-dependent activities as provided for under the city’s shoreline master program may be allowed where there are no feasible alternatives that would have a less adverse impact on the wetland and other critical areas.

2. Actions allowed through the public agency utility exception, reasonable use exception, and variance sections of this title.

E. Category IV Wetlands. Activities and uses that result in unavoidable and necessary impacts may be permitted in Category IV wetlands and associated buffers in accordance with an approved critical area report and mitigation plan, and only if the proposed activity is the only reasonable alternative that will accomplish the applicant’s objectives.

F. Wetland Buffers.

1. Buffer Requirements. The standard buffer widths have been established in accordance with the best available science. They are based on the category of wetland and the habitat score as determined by a qualified wetland professional using the Washington State Wetland Rating System for Western Washington (Revised, Publication No. 14-06-029, October 2014), or as revised by the Washington State Department of Ecology. Additional buffer widths are added to the standard buffer widths. The buffer widths shall be as follows:

Wetland Category	Buffer width if wetland scores 3 – 4 habitat points	Additional buffer width if wetland scores 5 habitat points	Additional buffer width if wetland scores 6 – 7 habitat points	Additional buffer width if wetland scores 8 – 9 habitat points
Category I – Based on total score	75 feet	Add 30 feet	Add 90 feet	Add 150 feet
Category I – Bogs and wetlands of high conservation value	190 feet	NA	NA	Add 35 feet
Category I – Forested	75 feet	Add 30 feet	Add 90 feet	Add 150 feet
Category II – Based on score	75 feet	Add 30 feet	Add 90 feet	Add 150 feet
Category III (all)	60 feet	Add 45 feet	Add 105 feet	Add 165 feet
Category IV (all)	40 feet	NA	NA	NA

a. The use of the standard buffer widths requires the implementation of the following measures, where applicable, to minimize the impacts of the adjacent land uses:

Disturbance	Required Measures to Minimize Impacts
Lights	•	Direct lights away from wetland
Noise	•	Locate activity that generates noise away from wetland
	•	If warranted, as decided by the director, enhance existing buffer with native vegetation plantings adjacent to noise source
	•	For activities that generate relatively continuous, potentially disruptive noise, such as certain heavy industry or mining, establish an additional 10-foot heavily vegetated buffer strip immediately adjacent to the outer wetland buffer
Toxic runoff	•	Route all new, untreated runoff away from wetland while ensuring wetland is not dewatered
	•	Establish covenants limiting use of pesticides within 150 feet of wetland
	•	Apply integrated pest management
Stormwater runoff	•	Retrofit stormwater detention to match existing hydrology, and retrofit treatment for roads and existing adjacent development, on the development site
	•	Prevent channelized flow from lawns that directly enters the buffer
	•	Use low intensity development techniques (per Puget Sound Action Team publication on LID techniques)
Change in water regime	•	Infiltrate or treat, detain, and disperse into buffer new runoff from impervious surfaces and new lawns
Pets and human disturbance	•	Use privacy fencing or plant dense vegetation to delineate buffer edge and to discourage disturbance using vegetation appropriate for the ecoregion. Fencing must be in compliance with subsection G of this section
	•	Place wetland and its buffer in a separate tract or protect with a conservation easement
Dust	•	Use best management practices to control dust
Disruption of corridors or connections	•	Maintain connections to off-site areas that are undisturbed
	•	Restore corridors or connections to off-site habitats by replanting

b. If an applicant chooses not to apply the mitigation measures listed in subsection (F)(1)(a) of this section, then a thirty-three percent increase in the width of all buffers is required. All other mitigation listed in this title will be required where applicable.

c. The standard buffer widths assume that the buffer is vegetated with a native plant community appropriate for the ecoregion. If the existing buffer is unvegetated, sparsely vegetated, or vegetated with invasive species that do not perform needed functions, the buffer should either be planted to create the appropriate plant community or the buffer should be widened to ensure that adequate functions of the buffer are provided. Where a buffer planting plan is proposed, it shall include provisions for monitoring and maintenance to ensure success.

2. Measurement of Wetland Buffers. All buffers shall be measured from the wetland boundary as surveyed in the field. The width of the wetland buffer shall be determined according to the wetland category. The buffer for a wetland created, restored, or enhanced as compensation for approved wetland alterations shall be the same as the buffer required for the category of the created, restored, or enhanced wetland.

3. Increased Wetland Buffer Widths. The director shall require increased buffer widths in accordance with the recommendations of a qualified professional biologist and the best available science on a case-by-case basis when a larger buffer is necessary to protect wetland functions and values based on site-specific characteristics. This determination shall be based on one or more of the following criteria:

a. A larger buffer is needed to protect other critical areas;

b. The buffer or adjacent uplands has a slope greater than twenty-five percent or is susceptible to erosion and standard erosion-control measures will not prevent adverse impacts to the wetland.

4. Wetland Buffer Width Averaging. The director may allow modification of the standard wetland buffer width in accordance with an approved critical area report and the best available science on a case-by-case basis by averaging buffer widths. Averaging of buffer widths may only be allowed where a qualified wetlands professional demonstrates that:

a. It will not reduce wetland functions or values;

b. 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;

c. The total area contained in the buffer area after averaging is no less than that which would be contained within the standard buffer; and

d. The buffer at its narrowest point is greater than either three-fourths of the required width or seventy-five feet for Category I and II, fifty feet for Category III and twenty-five feet for Category IV.

G. Fencing of Wetlands.

1. The director shall condition any permit or authorization issued pursuant to this chapter to require the applicant to install a permanent fence as determined by the director at the edge of the wetland buffer, when fencing will prevent future impacts to the wetland.

2. The applicant shall be required to install a permanent fence around the wetland or buffer when domestic grazing animals are present or may be introduced on site.

3. Fencing installed as part of a proposed activity or as required in this subsection shall be designed so as to not interfere with species migration, including fish runs, and shall be constructed in a manner that minimizes impacts to the wetland and associated habitat. (Ord. 426.A § 1 (Exh. A) (part), 2016: Ord. 426 § 1 (Exh. A) (part), 2015: Ord. 389 § 1 (Exh. A) (part), 2011)

18.20.050 Performance standards – Mitigation requirements.

A. Mitigation Shall Achieve Equivalent or Greater Biological Functions. Mitigation for alterations to wetlands shall achieve equivalent or greater biologic functions. Mitigation plans shall be consistent with “Wetland Mitigation in Washington State, Part 2: Developing Mitigation Plans” (Version 1, Ecology Publication No. 06-06-011b, March 2006).

B. Mitigation Shall Result in No Net Loss. Wetland mitigation actions shall not result in a net loss of wetland area except when the lost wetland area provides minimal functions and the mitigation action(s) results in a net gain in wetland functions as determined by a site-specific function assessment.

C. 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 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.

D. Preference of Mitigation Actions. 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 on disturbed upland sites such as those with vegetative cover consisting primarily of exotic introduced species.

3. Enhancing significantly degraded wetlands.

4. Preserving high-quality wetlands that are under imminent threat.

E. Type and Location of Mitigation. Mitigation sites shall be selected using “Selecting Wetland Mitigation Sites Using a Watershed Approach (Western Washington)” (Ecology Publication No. 09-06-032, December 2009).

F. Mitigation Timing. Except where determined by the director due to weather or project conditions, 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 flora.

The director may authorize a one-time temporary delay, up to one hundred twenty days, in completing minor construction and landscaping when environmental conditions could produce a high probability of failure or significant construction difficulties. The delay shall not create or perpetuate hazardous conditions or environmental damage or degradation, and the delay shall not be injurious to the health, safety and general welfare of the public. The request for the temporary delay must include a written justification that documents the environmental constraints that preclude implementation of the mitigation plan. The justification must be verified and approved by the city, and include a financial guarantee.

G. Mitigation Ratios.

1. Acreage Replacement Ratios. Wetland buffers for all categories shall be replaced on a one-to-one ratio. The following ratios shall apply to creation or restoration of wetlands 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 in those cases. Ratios for rehabilitation and enhancement may be reduced when combined with one-to-one replacement through creation or reestablishment. See Table 1a or 1b, Wetland Mitigation in Washington State – Part 1: Agency Policies and Guidance – Version 1 (Ecology Publication No. 06-06-011a, Olympia, WA, March 2006, or as revised).

 

Category and Type of Wetland	Creation or Re-establishment	Rehabilitation	Enhancement	Preservation
Category I: Bog, Natural Heritage Site	Not considered possible	6:1	Case by case	10:1
Category I: Mature Forested	6:1	12:1	24:1	24:1
Category I: Based on Functions	4:1	8:1	16:1	20:1
Category II	3:1	6:1	12:1	20:1
Category III	2:1	4:1	8:1	15:1
Category IV	1.5:1	3:1	6:1	10:1

2. Increased Replacement Ratio. The director may increase the ratios under the following circumstances:

a. Uncertainty exists as to the probable success of the proposed restoration or creation;

b. A significant period of time will elapse between impact and replication of wetland functions;

c. Proposed mitigation will result in a lower category wetland or reduced functions relative to the wetland being impacted; or

d. The impact was an unauthorized impact.

3. Decreased Replacement Ratio. The director may decrease these ratios under the following circumstances:

a. Documentation by a qualified wetlands professional demonstrates that the proposed mitigation actions have a very high likelihood of success;

b. Documentation by a qualified wetlands professional demonstrates that the proposed mitigation actions will provide functions and values that are significantly greater than the wetland being impacted; or

c. The proposed mitigation actions are conducted in advance of the impact and have been shown to be successful.

4. Credit/Debit Method. To more fully protect functions and values and 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 and b, Olympia, WA, March 2006), the administrator 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: Operational Draft” (Ecology Publication No. 10-06-011, Olympia, WA, February 2011, or as revised).

H. Wetland Mitigation Banks.

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 director 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.

2. Replacement ratios for projects using bank credits shall be consistent with replacement ratios specified in the bank’s certification.

3. 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.

I. In-Lieu Fee. To aid in the implementation of off-site mitigation, the city may develop a program which prioritizes wetland areas for use as mitigation and allows payment of fees in lieu of providing mitigation on a development site. This program 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. The program should address:

1. The identification of sites within the city/county that are suitable for use as off-site mitigation. Site suitability shall take into account wetland functions, potential for wetland degradation, and potential for urban growth and service expansion; and

2. The use of fees for mitigation on available sites that have been identified as suitable and prioritized.

J. 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 “Interagency Regulatory Guide: Advance Permittee-Responsible Mitigation” (Ecology Publication No. 12-06-015, December 2012).

K. Alternative Mitigation Plans. The director 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 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. The administrator 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 (Ecology Publication No. 09-06-32, Olympia, WA, December 2009);

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. Mitigation according to subsection E of this section is not feasible due to site constraints such as parcel size, stream type, wetland category, or geologic hazards;

4. There is clear potential for success of the proposed mitigation at the proposed mitigation site;

5. The plan shall contain clear and measurable standards for achieving compliance with the specific provisions of the plan. A monitoring plan shall, at a minimum, meet the provisions in BMC 18.10.200(D);

6. The plan shall be reviewed and approved as part of overall approval of the proposed use;

7. 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;

8. Mitigation guarantees shall meet the minimum requirements as outlined in BMC 18.10.280;

9. Qualified professionals in each of the critical areas addressed shall prepare the plan;

10. The city may consult with agencies with expertise and jurisdiction over the resources during the review to assist with analysis and identification of appropriate performance measures that adequately safeguard critical areas. (Ord. 426.A § 1 (Exh. A) (part), 2016: Ord. 426 § 1 (Exh. A) (part), 2015: Ord. 389 § 1 (Exh. A) (part), 2011)