12.64.306 Street and Outdoor Space Guidelines

12.64.306 Street and Outdoor Space Guidelines.

A. Streets. New Streets are encouraged to be located alongside property lines. These new streets may require coordination with neighboring property owners in order to maximize the continuity of the new street network.

1. Public spaces should provide a variety of seating options, areas of sun and shade for year-round climatic comfort, shelter, and night lighting to encourage public activity and ensure safety.

2. Public spaces at or near the sidewalk level are preferred. Public spaces that are not at sidewalk level or that extend into the site should include wayfinding signage, avoid dead-end spaces, have passive visual connections (i.e., overlooking windows, decks, terraces, and/or balconies), and, if deemed desirable, active (i.e., video) surveillance.

3. Projects with grouped outdoor mailbox areas are encouraged to incorporate those areas in or adjacent to their public space, including, where appropriate, widened passage areas.

a. Front yard fences should employ a combination of thick and thin structural elements with thicker elements for supports and/or panel divisions. Fence posts and/or support columns should be defined using additional trim, caps, finials, and/or moldings.

b. All walls should have a cap and base treatment.

c. Frontage walls may occur as garden walls, planter walls, seat walls, or low retaining walls.

d. Entrances and pedestrian “gateways” should be announced by posts or pilasters, and may be combined with trellises, special landscaping, decorative lighting, public art, or other special features.

a. Side yards and rear yards may contain landscape features that protect the privacy of the property’s occupants such as landscaping, trees and screening walls.

b. Screening fences and walls should be constructed of materials that are compatible with the architecture and character of the site. Natural colors, a cap or top articulation, and related dimensional post spacing increments should be used in screening fences to enhance compatibility.

c. Design elements should be used to break up long expanses of uninterrupted walls, both horizontally and vertically. Walls should include design elements such as textured concrete block, interlocking “diamond” blocks, formed concrete with reveals, or similar materials. Landscape materials should also be used to provide surface relief.

a. Use of security fences should be minimized, and limited to special locations where additional security is necessary. Such security fences should not exceed 6 feet in height.

b. Security fences should be designed to maintain a visually open character to the extent possible. This may be accomplished by using metal picket or open grille fencing or by mounting metal picket or open grille fencing on top of a low masonry wall.

a. Piers are architectural elements of fences or walls that can add interest to and break up long expanses.

b. Piers are recommended to have a base, shaft, and cap composition. Larger piers may be specially designed for gateway or other special locations, and these may incorporate ornamental plaques or signs identifying the building or business; public art such as panels or sculptural elements; and /or light fixtures. Piers may be topped by ornamental finials, light fixtures, or roof caps.

c. Recommended dimensions for masonry piers are approximately 18 inches per side or diameter, and the maximum spacing between piers should be 20 feet.

a. All fences and walls should be built with attractive, durable materials that are compatible with the character of Bothell (see BMC 12.64.500).

b. Appropriate fence materials include wood, masonry, and metal.

i. Wood picket fences are only recommended along residential streets. For wood picket fences, a paint finish or vinyl coating should be applied.

ii. For iron or metal fences, recommended materials include wrought iron, cast iron, welded steel, tubular steel, or aluminum. Metal fences should be mounted on a low masonry wall, and/or between masonry piers.

c. Appropriate wall materials include stone, brick, precast concrete, textured concrete block, or formed concrete with reveals and/or an architectural finish. A stucco finish may be used over a masonry core, except in the Downtown Special Review Area.

i. Exposed block walls should be constructed with a combination of varied height block courses and/or varied block face colors and textures (e.g. a combination of split-face and precision-face blocks). Plain gray precision-face concrete block walls are discouraged. Design treatments and finishes previously described should be applied to these walls for improved visual compatibility with building architecture.

ii. An anti-graffiti coating is recommended for exposed masonry wall surfaces and should be clean, colorless, and without sheen.

d. Support post or pier materials may differ from fence materials; e.g. metal fence panels combined with masonry piers. Recommended materials include brick, terra cotta, and stone, colored or decoratively treated cast-in-place concrete, precast concrete or concrete block, or stucco-faced concrete or concrete block. (Note: Stucco-faced concrete or concrete block are not permitted in the Downtown Special Review Area).

e. Bollards are recommended to be cast iron, cast aluminum, or precast concrete. An anti-graffiti protective coating is recommended for precast concrete.

f. Colors and finishes of mechanical enclosures and equipment should be coordinated with colors and finishes of streetlights, fencing, and other painted metal surfaces to be used on site, or with the associated building’s material and color scheme.

g. Street and building-mounted metal furnishings should be powdercoated or painted with Waterborne Acrylic Polyurethane, such as Tnemec Series 1080 or similar product. For powdercoated finishes, a chemically compatible UV-protectant clear coat is recommended for prevention of color fading.

1. Public gathering places and other publicly accessible areas should be detailed with decorative, pedestrian-scaled site furnishings and equipment.

2. Seating, freestanding planters, ornamental solid waste and recycling receptacles, bike racks, drinking fountains, pergolas, trellises, heaters, umbrellas, wind screening, and decorative bollards are recommended.

3. When designing seat walls with straight edges of more than six feet in length, consider detailing that will prevent skateboard damage.

4. Landscape structures and sculptural objects should reference the human scale in their overall massing and detailing.

5. Components should be made of durable high quality materials such as painted fabricated steel, painted cast iron, painted cast aluminum, and integrally colored precast concrete. Recycled materials should be used so long as the finish or look of the material is consistent with or similar to the finishes prescribed above. Metal surfaces should be coated with highly durable finishes such as aliphatic polyurethane enamel.

1. Plant materials should always be incorporated into new development site design to provide “softening” of hard paving and building surfaces.

2. Mature, existing trees should be preserved whenever possible.

3. Tree sizes should be suitable to lot size, the scale of adjacent structures, and the proximity to utility lines.

4. For street trees and plaza trees to be installed within paved areas, the use of structural soil planting beds, continuous soil trenches, or root path trenches is strongly recommended in order to maximize the ability of the tree to thrive and perform well in the urban environment.

5. Both seasonal and year-round flowering shrubs and trees should be used where they can be most appreciated – adjacent to walks and recreational areas, or as a frame for building entrances and stairs.

6. In general, deciduous trees with open branching structures are recommended to ensure visibility to retail establishments. More substantial shade trees are recommended in front of private residences.

7. Evergreen shrubs and trees should be used for screening along rear property lines, around solid waste/recycling areas and mechanical equipment, and to obscure grillwork and fencing associated with subsurface parking garages.

a. Lighting fixtures should generally be directed downward from the horizontal plane of the light source to preserve a dark sky and prevent unnecessary light pollution. Exceptions may be made for uplit trees and exterior architectural lighting. Reference citywide lighting regulations in BMC 12.14.240 for additional detailed regulations.

b. Pedestrian-oriented areas, including walkways and paths, plazas, parking lots, and parking structures shall be illuminated to increase safety and provide clear views both to and within the site.

c. All on-site and building-mounted lighting fixture design should be architecturally compatible with building design and with the character of the corridor.

d. Unnecessary glare from unshielded or undiffused light sources should be avoided. Commercial buildings and landscaping can be illuminated indirectly by concealing light features within buildings and landscaping to highlight attractive features and avoid intrusion into neighboring properties.

a. Color and finish of lighting metalwork should match that of other site furnishings, and/or of the building’s metalwork or trim work.

b. A chemically compatible UV-protectant clear coat over paint or powdercoat on metalwork is recommended for prevention of fading of dark or fugitive colors.

c. Color of lighting source types: in pedestrian-intensive areas, warm white, energy efficient source types (with color temperatures specified as 2700 degrees Kelvin to 3200 degrees Kelvin) such as metal halide, induction lighting, compact fluorescent, and light-emitting diode (LED) are strongly encouraged.

a. New area lighting fixtures should be of the cutoff type to prevent light from being emitted above a horizontal line relative to the point of light source.

b. New fixtures should use a reflector and/or a refractor system for efficient distribution of light and reduction of glare.

c. New fixtures should not cause glare or transmit it to upper stories of buildings. House-side shields and internal reflector caps should be used to block light from illuminating residential windows.

d. Small decorative “glow” elements within a luminaire are permitted to emit a low amount of light above the horizontal.

a. For building-mounted lights, maximum mounting height should be approximately 12 feet above finished grade.

b. For pole-mounted lighting at pedestrian plazas, walkways, and entry areas, a pedestrian-height fixture 12 to 14 feet in height from city-approved finished grade to light source should be used.

c. Bollard mounted lighting and stair lighting are also recommended for low-level illumination of walkways and landscaped areas.

d. Bollard illumination should be shielded or kept at a sufficiently low level to prevent glare impacts for passing motorists.

e. In general, height of light sources should be kept low to maintain pedestrian scale and prevent spill light from impacting adjacent properties.

a. Building façade uplighting, roof “wash” lighting, and landscape uplighting should be operated on timers that turn off illumination entirely after midnight nightly.

b. Shielding and careful placement should be used to prevent spill light from being visible to pedestrians, motorists, and nearby residential dwelling windows.

c. Adjacent to single-family homes, a combination of lower mounting height and luminaire shields should be used to protect residences from spill-light and glare.

d. Illumination levels of façade uplighting, roof wash lighting and landscape uplighting should use lower brightness levels where the illuminated façades, roofs or landscaping face residential buildings, except across wider streets or boulevards with landscaped medians and street trees.

G. Sustainability. See also related sustainability guidelines under BMC 12.64.404(C) (Parking Guidelines - Sustainability) and 12.64.503(D) (Architectural Elements – Sustainability Guidelines). In addition to the guidelines below, further requirements and guidelines are anticipated to be developed as part of the city’s sustainability initiative.

a. Shade trees should be planted to shade buildings’ east and west-facing windows to provide a balance between summer cooling and winter heating through solar gain.

b. Water conservation through the use of drip irrigation, captured rainwater, or recycled wastewater systems for plant irrigation or other non-potable uses is strongly encouraged

c. Plant selection and landscaping design that requires permanent irrigation systems should be avoided. Temporary irrigation systems for plant establishment are recommended.

d. Plant and landscape materials should be selected from native species as well as non-native/non-invasive species that are well adapted to the climatic conditions of Bothell. They should be resistant to local parasites and plant diseases.

e. All landscaped areas should be designed to allow aquifer filtration and minimize stormwater run-off utilizing bio-swales, filtration strips, and bio-retention ponds where appropriate.

f. As part of new street construction or sidewalk improvements, landscaped areas within the street right-of-way should be designed to be functional stormwater treatment facilities where appropriate.

Fig. 12.64.306.G. Example of a Rain garden configuration for urban locations where space is limited

2. Paved Areas. The grading of all paved areas and adjacent non-paved areas, the selection of paving materials, and the design of drainage facilities should consider paving permeability and be configured to allow water run-off to percolate back into native soil to the degree possible. Utilize pervious pavement to the degree practical.

3. Street & Block Configuration. In order to maximize solar access, new blocks should be configured such that the primary axis and longest face of the block closely aligns to geographical east/west.

4. Materials. Local and recycled building materials should be used whenever possible.

5. Heat Island Reduction. In order to reduce heat island effects on local microclimate and habitat:

a. Open grid pavement systems and/or paving materials with a Solar Reflective Index (SRI) of at least 29 are recommended.

b. Maximize summer shading from tree canopy.

c. Minimize surface parking by providing structured parking.

6. Site disturbance. Construction impact zones should be created to minimize site disturbances due to grading or other construction activity. Impact zones should be limited to within 40 feet of building perimeters, 10 feet of imperviously paved areas, 15 feet of curbed roadways, and 25 of permeable surfaces that require additional staging areas to limit compaction in the construction area. (Ord. 2337 § 4, 2020).