Mukilteo City Zoning Code
CHAPTER 17
52C FISH AND WILDLIFE HABITAT CONSERVATION AREAS OUTSIDE SHORELINE JURISDICTION
§ 17.52C.010 Purpose.
The purpose of this chapter is to protect areas that serve a critical role in sustaining healthy populations of plant and animal species. These regulations are intended to ensure that development is conducted in a manner that preserves essential habitat functions such as water quality, vegetation cover, habitat connectivity, food and shelter.
(Ord. 1533, 3/23/2026)
§ 17.52C.020 Applicability.
A.
General. This chapter applies to any new development activity within a designated fish and wildlife habitat conservation area (FWHCA), unless the activity is specifically exempt from the city's critical areas regulations. FWHCAs are defined in Chapter 17.08.
B.
Limited applicability to existing development. Enhancement of FWHCAs degraded by development legally established before the adoption of these regulations is not required. Development and activities existing prior to the adoption of the ordinance codified in this chapter may continue. Legally established impervious areas may be redeveloped without mitigation as long as the total square footage and location of impervious surface remains unchanged.
C.
Streams. These regulations apply to all F and N water types. Type S waters are shorelines of the state that are regulated by the city's Shoreline Master Program and Title 17B.
1.
Type F waters. Streams with continuous or seasonal flows that contain fish habitat.
2.
Type Np waters. Streams with continuous flows that do not contain fish habitat.
3.
Type Ns waters. Streams with seasonal flows that do not contain fish habitat.
D.
Riparian management zones (RMZs). These regulations apply within all riparian management zones.
1.
The RMZ for Type F waters is based on the site potential tree height at 200 years (SPTH200) as mapped by the Washington State Department of Fish and Wildlife. Where no SPTH data is available, the RMZ is 200 feet.
2.
The RMZ for Type N waters is 100 feet.
3.
The RMZ is measured from the outer edge of the channel migration zone (CMZ) where one exists. Otherwise, the RMZ is measured from the ordinary high water mark (OHWM).
E.
Priority habitats and species. These regulations apply to areas with which state or federally endangered, threatened, or sensitive species have a primary association. Priority habitats and species identified by WDFW's Priority Habitats and Species Program are also subject to provisions of Chapter 17.52B.
F.
Other. These regulations also apply to:
1.
Areas identified by the Washington State Department of Natural Resources' Natural Heritage Program as having rare plant species and high-quality ecosystems.
2.
Commercial and recreational shellfish areas.
3.
Kelp and eelgrass beds.
4.
Herring, smelt, and other forage fish spawning areas.
5.
Naturally occurring ponds under 20 acres and their submerged aquatic beds that provide fish or wildlife habitat.
6.
Waters of the state.
7.
Lakes, ponds, streams, and rivers planted with game fish by a governmental or tribal entity.
8.
State natural area preserves, natural resource conservation areas, and state wildlife areas.
(Ord. 1533, 3/23/2026)
§ 17.52C.030 Required reports, plans, and sureties.
A.
Adherence to the recommendations required. All recommendations in required reports are considered conditions of approval. Failure to follow report recommendations will be considered a violation of permit conditions.
B.
Biological/habitat assessment report.
1.
Required. A biological/habitat assessment report is required when development activity is proposed within 50 feet of a fish and wildlife habitat conservation area.
2.
Standards. The report must use best available science and be prepared by a qualified professional who is a biologist with experience preparing reports for the relevant type of habitat.
3.
Contents. The report is intended to be an investigation of the project area to evaluate the quality and type of habitats present and make protection and mitigation recommendations. It must:
a.
Provide a detailed description of vegetation on and adjacent to the project area.
b.
List priority species on or near the project area, including:
i.
Endangered, threatened, sensitive, or candidate species that have a primary association with habitat on or near the project area.
ii.
Vulnerable aggregations of species or animals susceptible to significant population declines within the specific area.
iii.
Species of recreational, commercial, and/or tribal importance.
c.
Identify priority habitats on or near the project area, including any areas that have one or more of the following attributes:
i.
Comparatively high fish and wildlife density.
ii.
Comparatively high fish and wildlife species diversity.
iii.
Important fish and wildlife breeding habitat.
iv.
Important fish and wildlife seasonal ranges.
v.
Important fish and wildlife movement corridors.
vi.
Limited availability.
vii.
High vulnerability to habitat alteration.
viii.
Unique or dependent species.
d.
Discuss any relevant federal, state, or local special management recommendations for species or habitats located on or near the project area. For projects near eagle habitat, analysis of compliance with the federal Bald and Golden Eagle Protection Act and the Migratory Bird Treaty Act is required.
e.
Assess the direct and indirect potential impacts on habitat or water quality.
f.
Review how the proposed activity complies with mitigation sequencing requirements.
g.
Make recommendations for mitigation, management, monitoring, and maintenance measures, including any buffers or revegetation necessary to protect the integrity, functions and values of the affected habitat.
h.
Contain a clear finding that if recommendations are followed, the development activity will not result in any loss of ecological function for the fish and wildlife conservation area.
4.
Expiration. Reports are valid for five years. Reports older than five years at the time of permit submittal must be updated.
C.
Monitoring program. When mitigation measures are required to ensure no net loss, a monitoring program must be established. The program must provide for at least five years of monitoring to ensure the mitigation performance standards are met. Monitoring programs must include:
1.
Performance standards.
2.
Metrics that will be reviewed in monitoring reports.
3.
Remediation measures if metrics aren't met.
4.
Schedule for submitting annual reports.
D.
Sureties. When mitigation measures are needed, an acceptable surety device must be put in place to ensure both performance and maintenance of the required mitigation.
1.
Performance surety. Mitigation must be installed prior to occupancy or final inspection. A performance surety equal to 150% of the cost of the mitigation project may be used to defer the timeline for installation by up to six months.
2.
Maintenance surety. A maintenance surety is required on all mitigation projects to ensure that the improvements survive for the established monitoring period. The surety must equal 15% of the cost of the mitigation project and reflect the term of the monitoring program.
E.
Third-party review. The city may retain a qualified professional, at the applicant's expense, to review and confirm any findings in required delineations, reports, studies, or plans.
(Ord. 1533, 3/23/2026)
§ 17.52C.040 Standards for all fish and wildlife habitat conservation areas.
A.
Performance standards. Applicants must specifically address how each of the following performance measures were addressed, or why they were not considered applicable or feasible:
1.
Consider habitat in site planning and design.
2.
Locate buildings and structures in a manner that minimizes impacts.
3.
Integrate retained habitat areas into open space or landscaping.
4.
Consolidate habitat and vegetated open space in contiguous blocks.
5.
Locate habitat contiguous to other habitat areas, open space, or landscaping to create corridors.
6.
Use native species in any on-site landscaping or replanting areas.
7.
Emphasize heterogeneity and structural diversity of vegetation in landscaping.
8.
Remove or control any nonnative or undesirable species of plants and animals on site.
9.
Preserve significant trees, preferably in groups.
10.
Locate mitigation to create and maintain contiguous habitat corridors.
B.
Mitigation. Any impacts to fish and wildlife habitat conservation areas must be mitigated at a one-to-one ratio to restore and preserve original functions. Mitigation measures must be in place prior to issuing the Certificate of Occupancy.
(Ord. 1533, 3/23/2026)
§ 17.52C.050 Additional development standards for streams.
A.
General. Except as otherwise specified or allowed, streams must be retained in an undisturbed condition.
B.
Allowed activities. The director may authorize the following activities when a report prepared by a qualified professional contains clear findings that there will be no net loss of stream functions or habitat value:
1.
Restoration activities. Restoration and enhancement activities to restore stream functions, provided a hydraulic project approval (HPA) is obtained from the Washington Department of Fish and Wildlife.
2.
Relocation. Stream relocation that is part of an approved mitigation or rehabilitation plan that has demonstrated that it will result in equal or better habitat and water quality and equivalent flow capacity.
3.
Culverts. Culverts for street and driveway crossings when fish passage will not be impaired and all of the following design criteria are met:
a.
A hydraulic project approval (HPA) is obtained from the Washington Department of Fish and Wildlife.
b.
Culvert exceeds diameter needed to accommodate flow.
c.
Culvert includes gradient controls and creation of pools.
d.
Gravel substrate at least one foot deep is placed in bottom of culvert.
C.
Additional protections for anadromous fish.
1.
Work window limitations. All activities in streams used by anadromous fish must comply with the work windows designated by the Washington Department of Fish and Wildlife for the applicable species.
2.
Erosion control. Bioengineering methods or soft armoring techniques are required.
3.
Barriers prohibited. Structures that prevent the migration of salmonids are not allowed in water bodies currently or historically used by anadromous fish. Fish bypass facilities must be provided and designed to allow the upstream migration of adult fish and prevent harm to fry and juveniles migrating downstream.
4.
Fill restrictions. Fill is only allowed for water-dependent uses where all impacts can be properly mitigated.
(Ord. 1533, 3/23/2026)
§ 17.52C.060 Additional development standards for riparian management zones.
A.
General. Except as otherwise specified or allowed, riparian management zones must be retained in an undisturbed condition.
B.
Allowed activities. The director may authorize the following activities when a report prepared by a qualified professional contains clear findings that there will be no net loss of stream functions or habitat value:
1.
Pedestrian trails, bridges, viewing platforms, and interpretative signage located to minimize disruption and avoid significant trees where feasible.
2.
Stormwater recharge facilities that benefit the habitat.
3.
Utility easements and underground utilities.
4.
Stormwater management facilities when no other location is feasible.
C.
Riparian management zone reductions.
1.
Obstructions. When a road or structure falls within an established RMZ and completely obstructs all ecosystem functions and values, the RMZ width may be modified to be the edge of the road or structure.
2.
Averaging with enhancements. RMZs may be reduced by up to 20% when:
a.
The total amount of riparian habitat area on site remains unchanged.
b.
No portion of the RMZ is less than 100 feet.
c.
Significant enhancements (e.g., revegetating all on-site portions of a degraded RMZ to meet or exceed 80% native vegetation coverage, daylighting a stream, or removing a fish barrier to restore accessibility to resident or anadromous fish) are proposed.
d.
A report prepared by a qualified professional contains clear findings that the result of the reduced areas and enhancements will provide equal or better protection of critical area functions and values than the standard zone width.
D.
Work window limitations. Any authorized work in a RMZ associated with a stream used by anadromous fish must comply with the work windows designated by the Washington Department of Fish and Wildlife for the applicable species.
(Ord. 1533, 3/23/2026)
