The city will apply the following general methods and mechanisms to accomplish the purposes of this chapter. This section shall be applied to all approved development applications and alterations where critical areas may be affected. Remediation and compensation, for wetlands and streams, may be accomplished using mitigation banking described in this section.
A. Mitigation Sequencing. Conditions to protect critical areas shall be sequenced as follows:
1. Avoid the impact by refraining from certain actions or parts of an action to the extent feasible;
2. Minimize the impacts by limiting the degree or magnitude of the action, by redesigning the proposed project to minimize impacts and/or avoid or reduce impacts by using appropriate technology, best management practices and design strategies;
3. Remediate the impact by repairing, rehabilitating, or restoring the affected environment;
4. Reduce or eliminate the impact over time by preservation and maintenance operations;
5. Compensate for the impacts by creating, replacing, enhancing, or providing substitute resources or environments;
6. Monitor the mitigation provided for the impact and take appropriate corrective measures when necessary.
B. Buffers.
1. Measurement of Buffers. All buffers shall be measured perpendicular from the critical area boundary as surveyed in the field. For buffer width determination and measurement purposes, the "critical area" excludes the buffer area. The width of the buffer shall be determined according to the category of the critical area and the proposed land use, as described in this chapter.
2. Standard Buffers. The standard buffer widths presume the existence of a native forest vegetation community in the buffer zone adequate to protect the critical area functions and values at the time of the proposed activity. If existing buffer is sparsely vegetated or vegetated with invasive species, the city may require an increase in the buffer width or additional native plantings within the standard buffer width. Provisions to reduce or to average buffer widths to obtain optimal habitat value are provided under the performance standards for each critical area.
3. Buffer Averaging. The director may allow wetland or stream buffer averaging only when the buffer area width after averaging will not adversely impact the critical area and/or buffer functions and values, including wetland hydrology that causes short- or long-term changes in native vegetation composition, soil characteristics, nutrient cycling or water chemistry. At a minimum, any proposed buffer averaging shall meet the following criteria:
a. The resulting buffer area is no less than that which would be provided by the standard buffer;
b. The buffer width shall not be reduced by more than 25 percent at any one point as a result of the buffer averaging, and provided, buffer averaging shall not result in a wetland buffer being reduced to less than 25 feet at any one point in any case;
c. The buffer area is reduced by averaging only in those locations where the least significant upland habitat is present within the standard buffer zone, and the areas for increased buffer incorporate the highest functioning upland habitats, where feasible;
d. The buffer area may be required to be enhanced where the buffer is allowed to be reduced, if the buffer is in a degraded condition;
e. The areas of expanded buffer width are contiguous with the standard buffer;
f. Encroachment into the buffer does not occur waterward of the top of an associated steep slope or into a channel migration zone;
g. Encroachment does not occur into the buffer of an associated wetland except as otherwise allowed; and
h. Buffer averaging shall not result in the relocation of any portion of a buffer onto an adjacent property not in common ownership.
4. Increased Buffer Widths. Buffers of prescribed widths are established in this chapter for various categories of wetlands, streams, geologically hazardous areas and channel migration zones. The director may require increased buffer widths as necessary to protect critical areas when either the critical area is particularly sensitive to disturbance or the development poses unusual impacts. Examples of circumstances that may require buffers beyond minimum requirements include, but are not limited to:
b. The critical area is in a sensitive drainage basin or documented salmonid spawning or rearing habitat;
c. The critical area is fish habitat for spawning or rearing as determined by the Washington Department of Fish and Wildlife;
d. The land adjacent to the critical area and its associated buffer, and located within the development proposal, is classified as an erosion hazard area; or
e. A trail or utility corridor in excess of 10 percent of the buffer width is proposed for inclusion in the buffer.
5. Functionally Isolated Wetland Buffers and Riparian Management Zones. Areas that provide no ecological functions or values which are functionally separated from a wetland or stream by legally established roads, impervious surfaces, or structures, shall be excluded.
6. Single-family residences part of a previously approved development are allowed improvements with a maximum footprint of 250 square feet, such as decks, patios, and appurtenances.
C. Building Setback Line. A building setback line of 15 feet shall be required from the edge of a buffer for any building or structure to ensure that the exteriors of the building or structure can be improved, maintained or repaired without encroaching into the buffer. Trails, sidewalks, parking lots, or stormwater facilities may be located within the building setback line as long as access for maintenance will not result in adverse impacts to the actual buffer.
D. Land Segregation. Subdivisions, short subdivisions, binding site improvement plans, boundary line adjustments and any other division of land in critical areas and buffers shall be subject to the following provisions:
1. Land that is wholly within a wetland or stream or buffer may not be subdivided or the boundary line adjusted except as approved under a reasonable use permit. In the case of land where one parcel is entirely within a wetland or stream buffer and an adjacent parcel is located partially or entirely out of a wetland or stream buffer, the provisions of subsection
B of this section shall apply to boundary line adjustments between the two parcels.
2. Land that is partially within a wetland or stream or buffer may be divided or the boundary line adjusted to create buildable lots; provided, that an accessible and contiguous portion of each new or adjusted buildable lot is:
a. Located outside the wetland or stream and any associated buffer; and
b. Complies with the minimum lot size for the zoning district in which it is located, if applicable.
3. Accessory roads and utilities serving the proposed division of land may be permitted within the wetland or stream and associated buffer only if the city determines that no other feasible alternative exists.
E. Marking or Fencing.
1. Temporary Markers. The outer perimeter of wetland, stream, fish and wildlife habitat conservation areas, steep slopes and their associated buffer and the limits of these areas to be disturbed pursuant to an approved permit or authorization shall be marked in the field prior to site clearing in a manner approved by the city so no unauthorized intrusion will occur. Markers or fencing are subject to inspection by the director or his/her designee prior to the commencement of permitted activities. This temporary marking shall be maintained throughout construction and shall not be removed until directed by the director, or until permanent signs and/or fencing, if required, are in place.
2. Permanent Markers. Following the implementation of an approved development plan or alteration, the outer perimeter of the critical area or buffer that is not disturbed shall be permanently identified. The director shall approve sign locations during review of the development proposal. Along residential boundaries, the signs shall be at least four inches by six inches in size and spaced one per centerline of lot or every 75 feet for lots whose boundaries exceed 150 feet. At road endings, crossings, and other areas where public access to the critical area is allowed, the sign shall be a minimum of 18 inches by 24 inches in size and spaced one every 75 feet. This identification shall include permanent wood or metal signs on treated wood or metal posts. Signs shall be worded as follows:
CRITICAL AREA BOUNDARY |
Protection of this natural area is in your care. Alteration or disturbance is prohibited. Please call the City of Snoqualmie at (425) 888-5337 for more information. Removal of this sign is prohibited. |
3. Permanent Fencing. The director shall require permanent fencing where there is a likelihood of the intrusion into the critical area based on the development proposal. The director shall also require such fencing when, subsequent to approval of the development proposal, intrusions threaten conservation of critical areas. The director may use any appropriate enforcement actions including, but not limited to, fines, abatement, or permit denial to ensure compliance.
F. Mitigation Plans.
1. Whenever mitigation is required, the applicant shall prepare and submit a mitigation plan using a watershed approach for city review and approval.
2. General Mitigation Requirements. Mitigation for alterations to critical areas shall achieve equivalent or greater biological functions and may include, in the case of streams and wetlands, mitigation for adverse impacts upstream and downstream of the development proposal site. Mitigation sites for wetlands, streams, and fish and wildlife habitat conservation areas shall be located to achieve contiguous habitat to minimize the isolating effects of development on habitat areas. Mitigation of aquatic habitat should be located within the same aquatic system as the area disturbed, unless the applicant provides a sound ecological basis for providing it in as close proximity to the project site as feasible and as approved by the administrator. Mitigation shall address each function affected by the alteration to achieve functional equivalency or improvement on a per function basis. Increased ratios of mitigation area may be required for wetlands, and the buffers of streams or wetlands, as provided in this chapter.
3. Mitigation Plan Submittal Requirements. The required scope and content of a mitigation plan shall be established by administrative rule promulgated by the director. Mitigation plans for wetlands and streams shall be based upon the Wetland Mitigation in Washington State, Part 1: Agency Policies and Guidance – Version 2 (Ecology Publication 21-06-003, Olympia, WA, April 2021, or as revised) and Part 2: Developing Mitigation Plans – Version 1 (Ecology Publication Number 06-06-011b, Olympia, WA, March 2006, or as revised), and Selecting Wetland Mitigation Sites Using a Watershed Approach (Western Washington) (Publication No. 09-06-32, Olympia, WA, December 2009, or as revised) as it now exists or may hereafter be modified.
4. Mitigation Monitoring. The time period for mitigation monitoring shall be established per the administrative rule established per subsection (F)(3) of this section, and shall be subject to the following minimum standards. Monitoring for compensatory mitigation for alteration of a wetland or stream shall occur for a minimum of five years. In the case of forested and scrub-shrub wetlands, monitoring shall occur for a minimum of 10 years, with reports submitted in years 1, 2, 3, 5, 7, and 10 and shall be secured with a bond or assignment for security.
G. Habitat Study. A habitat study shall be required for all development proposals that the director determines may affect the habitat of a listed species. If one or more listed species is using the subject property, the following additional requirements shall apply:
1. The applicant using a qualified professional consultant shall submit a habitat management plan, which at a minimum shall identify the qualities that are essential to maintain viable habitat for listed species using the fish and wildlife habitat conservation area and identify measures to minimize the impact from proposed activities on the habitat. The applicant shall be guided by WDFW's priority habitats and species management recommendations pursuant to WAC
232-12-297.
2. Conditions shall be imposed, as necessary, based on the measures identified in the habitat management plan.
3. To retain adequate natural habitat for listed species, buffers may be established on a case-by-case basis as described in the habitat management plan.
H. Minimal Impacts and No Net Loss. All the regulations of this chapter shall be applied to uses, activities, modifications and development to ensure minimal impacts to and no net loss of ecological function.
I. Where impact to critical areas or their buffers cannot be avoided, the applicant shall demonstrate that the impact is authorized by the provisions of this chapter or a reasonable use exception.
(Ord. 1176 § 2, 2016; Ord. 1198 § 23 (Exh. E), 2017; Ord. 1313 § 1 (Exh. A), 2025)