A.
Designating Wetlands. All areas within the City meeting the wetland designation criteria, regardless of any formal identification, are hereby designated critical areas and are subject to the provisions of this chapter. Identification of wetlands and delineation of their boundaries shall be done in accordance with the Corps of Engineers wetlands delineation manual (Corps, 1987) and applicable regional supplement (Corps, 2010), as revised or as may be revised in WAC 173-22-035 and 173-22-080 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. Wetland delineations shall be documented on a ground verified map using either professional surveying methods or an equivalent professional method using GPS with submeter accuracy.
B.
Wetland Ratings. Wetlands, as defined by this chapter, shall be classified and scored using the 2014 Department of Ecology Washington State Wetland Rating System for Western Washington, Publication No. 23-06-009 (Hruby, 2014 or latest edition), which contains the definitions and methods determining whether the criteria below are met.
1.
Category I. Category I wetlands are:
a.
Wetlands of high conservation value that are identified by scientists of the Washington Natural Heritage Program/DNR;
b.
Bogs;
c.
Mature and old-growth forested wetlands larger than one acre; or
d.
Wetlands that perform many functions well (scoring 23 points or more).
These wetlands: (1) represent unique or rare wetland types; (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; or (4) provide a high level of functions.
2.
Category II. Category II wetlands are wetlands larger than one acre or those found in a mosaic of wetlands, or wetlands with a moderately high level of functions (scoring between 20 and 22 points).
3.
Category III. Category III wetlands have a moderate level of functions (scoring between 16 and 19 points) and can often be adequately replaced with a well-planned mitigation project. Wetlands scoring between 16 and 19 points generally have been disturbed in some way and are often less diverse or more isolated from other natural resources in the landscape than Category II wetlands.
4.
Category IV. Category IV wetlands have the lowest levels of functions (scoring fewer than 16 points) and are often heavily disturbed. These are wetlands that can often be adequately replaced with a well-planned mitigation project, or in some cases improved. However, experience has shown that replacement cannot be guaranteed in any specific case. These wetlands may provide some important functions, and should be protected to some degree.
C.
Buffer Areas.
1.
The establishment of buffer areas shall be required for all development proposals and activities in or adjacent to wetland areas. The purpose of the buffer shall be to protect the integrity, function, and value of the critical area, and/or to protect life, property and resources from risks associated with development on unstable or critical lands. Lawns, walkways, driveways, paved areas, and mowed or developed areas will not be considered wetland or stream buffers included in buffer area calculations when assessing whether adequate compensatory mitigation buffers have been provided. If the site has previously been disturbed, the buffer area shall be revegetated pursuant to an approved planting plan.
2.
Buffers shall be protected during construction by placement of a temporary barricade, on-site notice for construction crews of the presence of the critical area, and implementation of appropriate erosion and sedimentation controls.
3.
Native vegetation removal or disturbance is not allowed in established buffers, unless the removal or disturbance is part of a restoration activity or is allowed by other provisions of this chapter. In all cases, the removal or disturbance should be appropriately mitigated consistent with KMC § 18.55.200 and 18.55.210.
4.
Wetland buffers shall be established as follows:
Wetland Type | Buffer Width (Feet) Based on Habitat Score (Points) | ||
|---|---|---|---|
3-5 | 6-7 | 8-9 | |
Category I | 75 | 110 | 225 |
Category II | 75 | 110 | 225 |
Category III | 60 | 110 | 225 |
Category IV | 40 | 40 | 40 |
5.
To minimize the impacts of adjacent land uses, development proposals and activities proposed in or adjacent to wetland areas must implement the following measures if applicable:
Disturbance | Required Measures to Minimize Impacts |
|---|---|
Lights | • Direct lights away from wetland |
Noise | • Locate activity that generates noise away from wetland • If warranted, 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 and treatment for roads and existing adjacent development • Prevent channelized flow from lawns that directly enters the buffer • Use low impact development 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 • Place wetland and its buffer in a separate tract or protect with a conservation easement |
Dust | • Use best management practices to control dust |
6.
For wetlands that score six points or more for habitat function, a relatively undisturbed, vegetated corridor at least 100 feet wide shall be protected when feasible between the wetland and any other priority habitats as defined by the Washington State Department of Fish and Wildlife. Presence or absence of a nearby priority habitat must be confirmed by a qualified professional and documented in a critical areas report. The corridor must be protected for the entire distance between the wetland and the priority habitat by some type of legal protection such as a conservation easement or critical area tract.
7.
Measurement of Wetland Buffers. Wetland buffers shall be measured from the wetland edge as delineated and marked in the field using the methodology specified in subsection A of this section.
8.
Increased Wetland Buffer Widths. The city manager 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 or their functions;
b.
The buffer has a slope greater than 30 percent or is susceptible to erosion and standard erosion-control measures will not prevent adverse impacts to the wetland. In such cases, the buffer shall be increased to include the slope or the standard buffer shall be drawn from the top of the slope, whichever provides greater protection; or
c.
A degraded wetland buffer is present. In this case, the standard buffer on the entire site shall be increased by 33 percent unless new net impervious surface between the upland edge of the standard buffer and the upland edge of the potentially increased buffer equals or is less than 500 square feet or a buffer revegetation plan is provided meeting all of the following criteria:
(1)
The buffer revegetation plan shall be prepared by a qualified professional and the applicant shall fund a review of the plan by the City’s wetland consultant. Enhancements shall include revegetation with native species appropriate for the site, and may also include installation of special habitat features, such as snags, downed wood, bat boxes, or other wildlife habitats. The buffer revegetation plan shall meet the requirements for a mitigation plan as described in KMC § 18.55.220, including five years of maintenance and monitoring consistent with KMC § 18.55.280.
(2)
The degraded wetland buffer shall be enhanced at a 1:1 ratio relative to the total net new impervious surface located between the upland edge of the standard buffer and the upland edge of the potentially increased buffer, up to the total on-site square footage of degraded wetland buffer outside of any legal nonconformances. When the available degraded wetland buffer area is exceeded by the new net impervious surface area, the remaining required area of revegetation shall be implemented in degraded wetland, if present on the site.
(3)
If the total new net impervious surface area between the upland edge of the standard buffer and the upland edge of the potentially increased buffer exceeds the area of degraded wetland buffer outside of any legal nonconformances and degraded wetland, the applicant should consider opportunities to convert areas of legal nonconformances to enhanced buffer.
D.
Limited Exemptions.
1.
All isolated Category IV wetlands meeting certain criteria that are less than 4,000 square feet may be exempt from the requirement to avoid wetland and buffer impacts (KMC § 18.55.210(A)), and they may be altered or filled if the impacts are fully mitigated based on the remaining actions in KMC § 18.55.210(B) through (F). If available, impacts should be mitigated through the purchase of credits from an in-lieu fee program or mitigation bank, consistent with the terms and conditions of the program or bank. A critical areas report for wetlands meeting the requirements in KMC § 18.55.310 must be submitted that demonstrates that the wetland is eligible for this exemption by confirming that the following criteria are met:
a.
The wetland is not associated with riparian areas or their buffers;
b.
The wetland is not associated with shorelines of the state or their associated buffers;
c.
The wetland is not part of a wetland mosaic;
d.
The wetland does not score six or more points for habitat function based on the 2014 update to the Washington State Wetland Rating System for Western Washington: 2014 Update (Ecology Publication No. 14-06-029, or as revised and approved by Ecology); and
2.
All isolated Category IV wetlands meeting certain criteria that are less than 1,000 square feet may be exempt from the buffer provisions contained in this chapter. A critical areas report for wetlands meeting the requirements in KMC § 18.55.310 must be submitted that demonstrates that the wetland is eligible for this exemption by confirming that the following criteria are met:
(Ord. 11-0329 § 3 (Exh. 1); Ord. 19-0488 § 2 (Exh. 1); Ord. 24-0624 § 5 (Exh. C); Ord. 24-0624 § 5 (Exh. C))