20D.150.70 In-Water Structures.

20D.150.70-010 Purpose.

The purpose of this chapter is to provide standards and guidelines for the location and design of docks, marinas, boat launches, and similar in-water structures that have the potential to adversely impact natural shoreline resources. (Ord. 2486)

20D.150.70-020 Applicability.

(1) All in-water structures shall comply with the standards of this chapter.

(2) Critical Areas Restrictions. In-water structures are also subject to the requirements of RCDG 20D.140.30-030, Alteration of Wetlands, and RCDG 20D.140.20-040, Alteration of Riparian Stream Corridors. (Ord. 2486)

20D.150.70-030 Permitted In-Water Structures.

(1) In-water structures shall be allowed for the following purposes only:

(a) A water-dependent use, provided that proposals for new in-water structures demonstrate that the use cannot reasonably be accommodated by an existing in-water structure or mooring buoy;

(b) Public access;

(d) Construction of crossings for roads, regional light rail transit systems, bikeways or trails, provided the installation complies with the additional standards of RCDG 20D.140, Critical Areas. Note that bridge crossings are not permitted across Lake Sammamish.

(2) Restricted Locations. In-water structures shall be located away from critical habitat areas and public access facilities as follows:

(a) In-water structures shall not be located in salmon and steelhead spawning areas or freshwater clam beds.

(b) Marinas, boat ramps, float plane facilities and community boat docks shall be located a minimum of 100 feet from critical wildlife nesting areas, natural lake beaches, and Category I and II wetlands. Greater buffers may be required pursuant to RCDG 20D.140.20-050, Alteration of Fish and Wildlife Habitat Conservation Areas.

(c) Marinas, motorized boat ramps, float plane facilities, and private docks or piers shall be located a minimum of 100 feet from a public swimming beach.

(d) Marinas and boat ramps are prohibited on Bear and Evans Creeks. Marinas are prohibited on the Sammamish River.

(e) Floats are allowed on Lake Sammamish only.

(3) Floating homes are prohibited. (Ord. 2486)

20D.150.70-040 General Design Requirements for In-Water Structures.

(1) Proposals for in-water structures shall provide a pre-construction habitat evaluation, including an evaluation of salmon and steelhead habitat, freshwater clam habitat, and critical wildlife habitat, and a post-construction monitoring plan. They shall also include an evaluation of shoreline ecological functions and demonstrate how the project achieves no net loss of shoreline ecological functions.

(2) Proposals for in-water structures shall mitigate adverse impacts to fisheries, aquatic and wildlife resources, shoreline and native aquatic vegetation, and impacts to other natural shoreline systems. Mitigation may include, but is not limited to, joint use of existing structures, open decking on piers, replacement of nonnative vegetation, installation of in-water habitat features, or restoration of shallow water habitat. All proposals for in-water structures, except for single-family residential docks and piers, shall, at a minimum, meet the requirements of RCDG 20D.140.20-060, Riparian Stream Corridor Performance Standards and RCDG 20D.140.30-040, Wetland Performance/Design Standards.

(3) Protection of Vegetation.

(a) In-water structures shall be designed and located to minimize shading of native aquatic vegetation. Removal of shoreline, riparian and aquatic vegetation shall be limited to the minimum extent necessary to construct the project. All upland and aquatic areas disturbed by construction shall be replanted with native vegetation.

(b) In-water structures shall include the installation of native aquatic plants, such as hardstem bulrush (Scirpus acutus), below the ordinary high water mark to a minimum width of 10 feet to mitigate the effects of introduced structures on wave action and erosion.

Significant trees shall be protected and replaced adjacent to the water body, pursuant to RCDG 20D.150.110, Tree Protection, Landscaping and Screening Within Shorelines.

(4) New or replacement in-water structures shall be designed and located such that natural hydraulic and geologic processes, such as erosion, wave action, or floods will not necessitate the following:

(a) Reinforcement of the shoreline or stream bank with new bulkheads or similar artificial structures to protect the in-water structure;

(b) Excessive dredging; or

Replacement of in-water structures shall include proper removal of abandoned or other manmade structures and debris.

(5) All in-water structures shall be designed to allow for the free passage of water and fish. Intake pipes shall be screened to avoid impacting fish, consistent with the Washington Department of Fish and Wildlife’s Screening Guidelines.

(6) In-water structures are not subject to the waterfront setbacks or building setbacks otherwise provided for in the Community Development Guide. Specific types of in-water structures are subject to side property line setbacks as identified in the specific sections that follow.

(7) In-water structures shall not interfere with the public’s right of navigation. Where in-water structures are located adjacent to public piers, public beaches, or other public open space, such structures shall provide or enhance public access commensurate with the scale of the project’s impacts to public access.

(8) In-water structures shall be designed to minimize aesthetic impacts to the shoreline. In-water structures, excluding mechanical equipment associated with watercraft, shall consist of nonreflective or low-reflective material.

(9) Bulk storage of gasoline, oil and other petroleum products over the water or in the water is prohibited. (Ord. 2486)

20D.150.70-050 Piers, Docks and Floats.

Piers and docks are prohibited in the Sammamish River, Bear Creek, and Evans Creek. Where new or replacement piers, docks, floats or boardwalks are allowed, they shall meet the following additional conditions:

(1) Demonstrated Need.

(a) Where a proposed pier or dock is located within 100 feet of an existing pier or dock, the proposal shall demonstrate that a combined or shared facility is not available or feasible, or would not serve to reduce environmental impacts to shoreline resources. This shall not apply to piers and docks accessory to single-family residences. Easements or covenants assuring joint use and specifying maintenance responsibility shall be provided with a joint application.

(b) The proposal shall demonstrate that other means, such as floating moorage buoys or boat lifts, cannot accommodate the use or are not available or are infeasible.

(2) Number of Piers.

(a) No lot shall have more than one pier, dock or float structure, except as provided below:

(i) An additional pier, dock or float structure is allowed where such structure is open to, and accessible to the public.

(ii) A residential lot may include one float in addition to one pier or one dock.

(b) Finger piers supported by pilings are prohibited. Finger floats or docks are allowed.

(3) Each pier and float structure shall meet the length, width, height and area restrictions specified in this section.

(4) Floats. Where allowed, residential floats or over-water platforms may not exceed 60 square feet in area, except that where a lot does not have a pier or dock, floats may not exceed 80 square feet. Floats and over-water platforms must be located no closer than five feet from a property line, and no further waterward than the waterward extent of the primary pier or dock, or than the point where the water depth reaches 13 feet, whichever is less.

(5) Maximum Coverage. The maximum total water coverage by piers, docks and floats per lot shall be as follows (see Figures 1 and 2):

(a) In single-family residential zones: The lesser of 20 percent of the area bounded by the line of ordinary high water, the waterward projection of the side property lines, and the waterward extremity of the pier projected parallel to the line of ordinary high water or 480 square feet. Small finger docks attached to the main pier and floats shall be included in this maximum area.

(b) In multiple-family residential zones: The lesser of 25 percent of the area bounded by the line of ordinary high water, the waterward projection of the side property lines, and the waterward extremity of the pier projected parallel to the line of ordinary high water or 960 square feet. Small finger docks attached to the main pier and floats shall be included in this maximum area.

Figure 1: Example Maximum Pier Coverage

Single-Family Residential Zones

Figure 2: Example Maximum Pier Coverage

Multi-family Residential Zones

(6) Pier Length. The maximum pier or dock length from the shoreline shall be the lesser of 80 feet, or a length necessary to reach a water depth at the end of the pier of 13 feet below ordinary high water (see Figure 3).

Figure 3: Pier Length

(7) Pier Width. No pier or dock may exceed six feet in width. Floats may not exceed 10 feet in width.

(8) Pier Height.

(a) No pier or dock shall exceed four feet in height above ordinary high water.

(b) Railings, storage bins, signs, boat lifts and other features and structures accessory to piers, docks and floats shall have a height limit of four feet above the deck surface.

(c) Public access features accessory to a public pier or dock, such as seating areas or interpretive signs, shall not project more than four feet above the deck surface of a pier or dock, except that covered public shelters shall not exceed 12 feet in height above the deck surface.

(d) Skirting, decking lower than one vertical foot above ordinary high water, or similar structures around docks and floats are not allowed.

(9) Pier Setbacks. The minimum setback from any side property line is 10 feet, except that shared facilities may be located adjacent to or on both sides of a property line upon agreement of the affected property owners.

(10) Any utility lines serving a pier or dock shall be located below the pier deck or underground.

(11) Lighting for piers and docks shall be the minimum necessary to locate the dock at night, shall be designed to minimize glare, and shall incorporate cut-off shields or otherwise shall be directed downward toward the dock. Piers, docks and floats that are not lighted shall incorporate reflectors for nighttime visibility.

(12) Pilings and Decking. Piers, docks and pilings shall minimize shading of the water and habitat for salmonid predators by minimizing piling and decking area, as follows:

(a) Piers shall use steel pin pilings where wave action and substrate allow. Piers using traditional pilings shall use the minimum number of pilings necessary to support the pier and maximize the distance between pilings.

(b) The decking of all piers and docks shall be designed to allow 50 percent light passage. This may be accomplished through grated decks, light prisms, or other means.

(c) Piers shall be designed to span, without pilings, aquatic areas where summer water depths range between 3.3 and 6.6 feet deep.

(d) Pier platforms shall be designed and located to avoid or reduce shallow water (less than nine feet deep) shading.

(e) Preferred construction techniques include vibratory pile drivers rather than conventional hammer pile drivers.

(13) Wooden components that will be in contact with standing water or floodwaters shall not contain creosote, pentachlorophenol, or similar toxic substances. Use durable, nontoxic materials for wooden components protection. Structures shall be made out of materials that have been approved by applicable state agencies.

(14) New residential development of two or more dwellings shall provide joint use or community dock facilities rather than individual docks for each residence, when feasible. (Ord. 2486)

20D.150.70-060 Marinas and Boat Launches.

(1) Marinas in Publicly Owned Facilities. Marinas, boat ramps and boat launch sites located in publicly owned facilities such as parks must be available to the general public with no preference for private clubs or groups.

(2) All proposals for marinas and boat launching facilities that may require periodic removal of aquatic vegetation shall provide a comprehensive aquatic vegetation management and monitoring plan.

(3) Marinas and boat launching facilities shall be located no closer than 50 feet from another marina, boat launch, or dock.

(4) Marinas, boat ramps and launching sites shall be designed and located according to the following criteria:

(a) They shall not interfere with existing in-water recreational activities;

(b) They shall not significantly damage fish and wildlife habitats;

(d) They shall be aesthetically and functionally compatible with the shoreline area and nearby uses. Aesthetic impacts shall be avoided, or if not possible, aesthetic impacts shall be mitigated;

(e) They shall be located only at sites with suitable environmental conditions, shoreline configuration, access, and neighborhood uses.

(5) Boat launch ramps and vehicle access to the ramps shall be paved. Access to the ramp and parking for the ramp shall be located a sufficient distance from any frontage road to provide safe maneuvering of boats and trailers, and shall not be located through public beaches, or through critical habitat areas, including, but not limited to, Category I and II wetlands.

(6) Boat launch ramps shall be designed to minimize areas of landfill or shoreline protective structures.

(7) All facilities shall meet health, safety, and welfare requirements of appropriate state agencies.

(8) Covered moorage is prohibited.

(9) Commercial marinas are prohibited. Recreational marinas are permitted and shall provide public access.

(10) If a recreational marina allows live-aboard vessels, a Shoreline Conditional Use Permit shall be required.

(11) Marinas and boat launches shall not interfere with the rights of navigation.

(12) Vessels shall be restricted from extended mooring on waters of the state except as allowed by applicable state regulations and unless a lease or permission is obtained from the state and impacts to navigation and public access are mitigated. (Ord. 2486)

20D.150.70-070 Water-Oriented Accessory Structures.

Accessory structures that are water-oriented and accessory to a shoreline or water-dependent use shall meet the following standards:

(1) Water-oriented accessory structures are not subject to the waterfront building setbacks or side yard setbacks of the underlying zone (see RCDG 20C.30.25), unless otherwise noted below.

(2) Boathouses and similar water-oriented structures may extend no further waterward than the ordinary high water line. Such structures shall meet the minimum side yard setback required in the underlying zone, unless they are a joint use facility that serves more than one adjoining waterfront lot.

(3) Water-oriented accessory structures shall not exceed 10 feet in height and 250 square feet in area. However, multiuse structures that include storage and changing rooms may be a maximum of 500 square feet. The area of such covered structures shall be included in the maximum lot coverage and impervious surface limits of the zone in which they are located.

(4) Uncovered boat lifts and similar equipment or structures used for watercraft may be located waterward of the ordinary high water mark to the waterward limit of the associated pier or dock. Such structures associated with docks shall have a height limit of four feet above ordinary high water. Such structures associated with piers shall have a height limit of four feet above the deck of the pier. Where a boatlift is used in lieu of a pier, it may extend waterward of the ordinary high water mark, provided it does not exceed four feet above the OHWM in height and meets the side yard setback of the underlying zoning district. Covered boat lifts shall not exceed 96 inches in height as measured from the ordinary high water mark.

(5) Joint Use Accessory Structures. Water-oriented accessory structures that serve more than one adjoining waterfront lot may be constructed with a zero side setback from the common boundary, provided that the owners of such property enter into a reciprocal use agreement recorded with the King County Auditor. (Ord. 2486)