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A. Endangered, Threatened, and Sensitive Species. Whenever activities are proposed within or adjacent to a habitat conservation area with which state or federally endangered, threatened, or sensitive species have a primary association, such area shall be protected through the application of best management practices, based on habitat- or species-specific management recommendations published by state or federal agencies when available, in accordance with a critical areas report prepared by a qualified professional and approved by the city. Approval for alteration of land within or adjacent to the habitat conservation area or its buffer shall not occur prior to consultation with the Washington State Department of Fish and Wildlife for animal species, the Washington State Department of Natural Resources for plant species, and other appropriate federal or state agencies.

B. Anadromous Fish.

1. All activities, uses, and alterations proposed to be located in water bodies used by anadromous fish or in areas that affect such water bodies shall give special consideration to the preservation and enhancement of anadromous fish habitat, including, but not limited to, adhering to the following standards:

a. Activities shall be timed to occur only during the allowable work window as designated by the Washington State Department of Fish and Wildlife for the applicable species;

b. An alternative alignment or location for the activity is not feasible;

c. The activity is designed so that it will not degrade the functions or values of the fish habitat or other critical areas;

d. Shoreline erosion control measures shall be designed to use bioengineering methods or soft armoring techniques, according to an approved critical areas report; and

e. Any impacts to the functions or values of the habitat conservation area are mitigated in accordance with an approved critical areas report.

2. Structures that prevent the migration of salmonids shall not be allowed in the portion of water bodies currently or historically used by anadromous fish. Fish bypass facilities shall be provided that allow the upstream migration of adult fish and shall prevent fry and juveniles migrating downstream from being trapped or harmed.

3. Fills, when authorized by the Bothell Shorelines Master Program, shall not adversely impact anadromous fish or their habitat or shall mitigate any unavoidable impacts and shall only be allowed for a water-dependent use.

C. Wetland Habitats. All proposed activities within or adjacent to habitat conservation areas containing wetlands shall conform to the wetland development performance standards set forth in BMC 14.04.500 through 14.04.550. If non-wetlands habitat and wetlands are present at the same location, the provisions of this chapter or the wetlands chapter, whichever provides greater protection to the habitat, apply.

D. Riparian Habitat Areas. Unless otherwise allowed in this chapter, all structures and activities shall be located outside of the riparian habitat area.

1. Establishment of Riparian Habitat Areas. Riparian habitat areas shall be established for habitats that include aquatic and terrestrial ecosystems that mutually benefit each other and that are buffers located adjacent to rivers, perennial or intermittent streams, seeps, and springs.

2. Stream Buffer Widths. Standard stream buffer widths are shown in the table below. A stream buffer shall have the width recommended, unless a greater width is required pursuant to subsection (D)(3) of this section, or a lesser width is allowed pursuant to subsection (D)(4) of this section. Widths shall be measured outward in each direction, on the horizontal plane, from the ordinary high water mark, or from the top of bank, if the ordinary high water mark cannot be identified. Stream buffers should be sufficiently wide to achieve the full range of riparian and aquatic ecosystem functions, which include but are not limited to protection of in-stream fish habitat through control of temperature and sedimentation in streams; preservation of fish and wildlife habitat; and connection of riparian wildlife habitat to other habitats.

Stream Buffers1

Stream Type

Standard Stream Buffer Widths

Type S; or shorelines of the state, or shorelines of statewide significance

See BMC 13.13.060(E)(4)

Type F; or other salmonid bearing streams

100 feet

Type Np; or other perennial, non-salmonid bearing streams

75 feet

Type Ns; or other intermittent, non-salmonid bearing streams

50 feet

1While water typing is used here to classify riparian habitat areas, regulations regarding riparian habitat areas listed here are applicable to areas containing aquatic systems containing perennial or intermittent flowing water. See the definition for “riparian habitat.” Habitats associated with standing water are by the general and other performance standards in this chapter.

3. Increased Stream Buffer Widths. Standard stream buffer widths shall be increased, as follows:

a. When the director determines that the standard width is insufficient to prevent habitat degradation and to protect the structure and functions of the habitat area;

b. When the frequently flooded area exceeds the standard stream buffer width, the stream buffer shall extend to the outer edge of the frequently flooded area;

c. When the stream buffer is within an erosion or landslide hazard area, or buffer, the stream buffer width shall be the standard distance, or the erosion or landslide hazard area or buffer, whichever is greater.

4. Decreased Stream Buffer Widths. Where a site’s topographic features would make establishment of the required buffer infeasible or where those or other physical site characteristics would make the buffer nonfunctional, and where the characteristics were not created through deliberate action on the part of the property owner, the required buffer may be reduced, up to 25 feet, if two or more of the following critical areas enhancement measures are implemented:

a. The buffer is enhanced with non-invasive vegetation, especially that which would increase the value for fish and wildlife, increase streambank or slope stability, improve water quality, or provide aesthetic/recreational value; and/or

b. Fish barriers are removed to restore accessibility to anadromous fish; and/or

c. Fish habitat is enhanced using log structures incorporated as part of a fish habitat enhancement plan; and/or

d. Wildlife habitat structures that are likely to be used by wildlife are introduced or enhanced, including but not limited to wood duck houses, bat boxes, resting platforms, snags, rootwads/stumps and birdhouses.

5. Stream Buffer Width Averaging. The director may allow the standard stream buffer width to be reduced in accordance with a critical areas report only if:

a. The width reduction will not reduce stream or habitat functions, including those of non-fish habitat;

b. The width reduction will not degrade the habitat, including habitat for anadromous fish;

c. The proposal will provide additional habitat protection;

d. The total area contained in the stream buffer of each stream on the development proposal site is not decreased;

e. The standard stream buffer width is not reduced by more than 25 percent in any one location;

f. The width reduction will not be located within another critical area or associated buffer; and

g. The reduced stream buffer width is supported by the best available science.

6. Riparian Habitat Mitigation. Mitigation of adverse impacts to riparian habitat areas shall result in equivalent functions and values on a per function basis, be located as near the alteration as feasible, and be located in the same subdrainage basin as the habitat impacted.

7. Alternative Mitigation for Riparian Habitat Areas. The performance standards set forth in this subsection may be modified at the city’s discretion if the applicant demonstrates that greater habitat functions, on a per function basis, can be obtained in the affected sub-drainage basin as a result of alternative mitigation measures.

E. Aquatic Habitat. The following specific activities may be permitted within a riparian habitat area, pond, lake, water of the state, or associated buffer subject to the standards of this subsection:

1. Clearing and Grading. When clearing and grading is permitted as part of an authorized activity or as otherwise allowed in these standards, the following shall apply:

a. Grading is allowed only during the dry season, which is typically regarded as beginning on May 1st and ending on October 1st of each year; provided, that the city may extend or shorten the dry season on a case-by-case basis, determined on actual weather conditions.

b. Filling or modification of a wetland or wetland buffer is permitted only if it is conducted as part of an approved wetland alteration.

c. The soil duff layer shall remain undisturbed to the maximum extent possible. Where feasible, any soil disturbed shall be redistributed to other areas of the project area.

d. The moisture-holding capacity of the topsoil layer shall be maintained by minimizing soil compaction or reestablishing natural soil structure and infiltrative capacity on all areas of the project area not covered by impervious surfaces.

e. Erosion and sediment control that meets or exceeds the standards set forth in Chapter 18.05 BMC and the most recent version of the city’s Surface Water Design Manual shall be provided.

2. Streambank Stabilization.

a. New structures should be sited and designed to avoid the need for shoreline stabilization.

b. When streambank stabilization is demonstrated to be necessary to protect new or existing structures from erosion and less impactful measures are not feasible, stabilization shall be achieved consistent with WDFW’s Integrated Streambank Protection Guidelines (2003, or as revised) or equivalent state or federal agency guidance documents. Bioengineering or soft armoring techniques shall be used unless demonstrated to be infeasible in accordance with an approved critical areas report.

3. Launching Ramps – Public or Private. Launching ramps may be permitted in accordance with an approved critical areas report that has demonstrated the following:

a. The project will not result in increased beach erosion or alterations to, or loss of, shoreline substrate within one-quarter mile of the site;

b. The ramp will not adversely impact critical fish or wildlife habitat areas or associated wetlands;

c. Adequate mitigation measures ensure that there is no net loss of the functions or values of riparian habitat as a result of the ramp.

4. Docks. Repair and maintenance of an existing dock or pier may be permitted in accordance with an approved critical areas report subject to the following:

a. There is no increase in the use of materials creating shade for predator species;

b. There is no expansion in overwater coverage;

c. There is no new spanning of waters between three and 13 feet deep; and

d. There is no use of toxic materials (such as creosote) that come in contact with the water.

5. Roads, Trails, Bridges, and Rights-of-Way. Construction of trails, roadways, and minor road bridging may be permitted in accordance with an approved critical areas report subject to the following standards:

a. There is no other feasible alternative route with less impact on the environment;

b. The crossing minimizes interruption of downstream movement of wood and gravel;

c. Roads in riparian habitat areas or their buffers shall not run parallel to the water body;

d. Trails shall be located on the outer edge of the riparian area or buffer, except for limited viewing platforms and crossings;

e. Crossings, where necessary, shall only occur as near to perpendicular with the water body as possible;

f. Mitigation for impacts is provided pursuant to a mitigation plan of an approved critical areas report;

g. Road bridges are designed according to the Washington State Department of Fish and Wildlife Water Crossing Design Guidelines, 2013; and

h. Trails and associated viewing platforms shall not be made of continuous impervious materials.

6. Utility Facilities. New utility lines and facilities may be permitted to cross watercourses in accordance with an approved critical areas report, if they comply with the following standards:

a. Fish and wildlife habitat areas shall be avoided to the maximum extent possible;

b. Installation shall be accomplished by boring beneath the scour depth and hyporheic zone of the water body and channel migration zone, where feasible;

c. The utilities shall cross at an angle greater than 60 degrees to the centerline of the channel in streams or perpendicular to the channel centerline whenever boring under the channel is not feasible;

d. Crossings shall be contained within the footprint of an existing road or utility crossing where possible;

e. The utility route shall avoid paralleling the stream or following a down-valley course near the channel; and

f. The utility installation shall not increase or decrease the natural rate of shore migration or channel migration.

7. Public Flood Protection Measures. New public flood protection measures and expansion of existing ones may be permitted, subject to the city’s review and approval of a critical areas report and the approval of a Federal Biological Assessment by the federal agency responsible for reviewing actions related to a federally listed species.

8. In-stream Structures. In-stream structures, such as, but not limited to, high flow bypasses, sediment ponds, in-stream ponds, retention and detention facilities, tide gates, dams, and weirs, shall be allowed only as part of an approved watershed basin restoration project approved by the city and upon acquisition of any required state or federal permits. The structure shall be designed to avoid modifying flows and water quality in ways that may adversely affect habitat conservation areas.

9. Storm Water Conveyance Facilities. Conveyance structures may be permitted in accordance with an approved critical areas report subject to the following standards:

a. No other feasible alternatives with less impact exist;

b. Mitigation for impacts is provided;

c. Storm water conveyance facilities shall incorporate fish habitat features; and

d. Vegetation shall be maintained and, if necessary, added adjacent to all open channels and ponds in order to retard erosion, filter out sediments, and shade the water.

10. On-Site Sewage Systems and Wells.

a. New on-site sewage systems and individual wells may be permitted in accordance with an approved critical areas report only if accessory to an approved residential structure, for which it is not feasible to connect to a public sanitary sewer system.

b. Repairs to failing on-site sewage systems associated with an existing structure shall be accomplished by utilizing one of the following methods that result in the least impact:

(i) Connection to an available public sanitary sewer system;

(ii) Replacement with a new on-site sewage system located in a portion of the site that has already been disturbed by development and is located landward as far as possible, provided the proposed sewage system is in compliance with the King or Snohomish County health district (as applicable); or

(iii) Repair to the existing on-site septic system. (Ord. 2349 §§ 1, 2, 2021; Ord. 1946 § 3, 2005).