§ 21.60.140. Design standards.

A.

Open space requirements shall be as follows:

1.

Common Open Space. Each planned residential development shall provide not less than thirty percent of the gross land area for common open space which shall be either:

a.

Held in single ownership where such ownership assumes full responsibility for maintenance and operation; or

b.

Held in common ownership by all of the owners in the development area; or

c.

Dedicated for public use, if acceptable to the county.

2.

Common open space may contain such complementary structures and improvements as are necessary and appropriate for the benefit and enjoyment of residents of the PRD, provided that the building coverage of such building or structure combined with the building coverage of the residential structures shall not exceed the maximum permitted by the underlying zone.

3.

Up to fifty percent of the common open space requirement may be satisfied by the preservation of tall stands of trees and/or wetland and/or critical area habitat and required critical area buffers in consideration of the significant passive recreation opportunities provided by said lands. Development shall be configured to take advantage of these areas as a significant site amenity. These areas should be visually accessible to the public rather than walled off from view. To the extent possible, trail networks should be integrated with these areas. For example, a trail along the wetland buffer is a desirable option. The remaining fifty percent of the common open space area must meet the criteria in subsection (4) below.

4.

Common open space must meet the following design criteria:

a.

Must be usable and accessible. All common open spaces intended for public use shall be physically and visually accessible from the adjacent street or major internal pedestrian route. Open spaces shall be in locations accessible to intended users—rather than simply left—over or undevelopable space in locations where very little pedestrian traffic is anticipated. Locations integrated with transit stops, for instance, would be encouraged, as there is likely to be pedestrian traffic in the area.

b.

Open space area shall have convenient access for residences of the development and shall be consolidated to provide maximum access, visibility, usability, minimization of impacts to residential uses, and ease of maintenance.

c.

Must be inviting. Inviting open spaces feature amenities and activities that encourage pedestrians to use and explore the space. On a large scale, it could be a combination of active and passive recreational uses. It could include a fountain, sculpture, children's play area, special landscaping element, or even a comfortable place to sit and watch the world go by. In order for people to linger in an open space, it must be comfortable. For instance, a plaza space should receive ample sunlight, particularly at noon, and have design elements that lend the space a "human scale," including landscaping elements, benches and other seating areas, and pedestrian-scaled lighting. No use shall be allowed within the open space that adversely affects the aesthetic appeal or usability of the open space. (See Table 21T-83.)

d.

Must be safe. Safe open spaces incorporate Crime Prevention through Environmental Design (CPTED) principles:

(1)

Natural surveillance—which occurs when parks or plazas are open to view by the public and neighbors. For example, a plaza that features residential units with windows looking down on space means that the space has good "eyes" on the park or plaza.

(2)

Lighting that reflects the intended hours of operation.

(3)

Landscaping and fencing. Avoid configurations that create dangerous hiding spaces and minimize views.

(4)

Entrances should be prominent, well lit, and highly visible from inside and outside of the space.

(5)

Maintenance. Open spaces shall utilize commercial grade materials that will last and require minimal maintenance costs. Walls, where necessary, shall be designed and treated to deter graffiti. Use and maintain landscape materials that reduce maintenance cost and maintain visibility, where desired.

e.

Provides for uses/activities that appropriately serve the anticipated residents and users of the development. For example, common open space that serves a variety of functions will attract greater usage. When designing open spaces, project applicants should consider a broad range of age groups, from small children, to teens, parents, and seniors.

f.

Must be designed and placed in consideration of existing and potential open space on adjacent parcels to provide consolidation or opportunities for future consolidation of neighborhood open space areas.

g.

Additional Criteria.

(1)

Consolidation of open space is encouraged to provide maximum access, visibility, usability, minimization of impacts to residential uses, and ease of maintenance.

(2)

Existing trees and significant vegetation shall be retained in open space unless an alternative park/landscaping plan consistent with the criteria herein is approved by the department.

5.

Cash or like value of land area and improvements may be donated to the county for open space purposes to fulfill up to fifty percent of open space requirements within that specific parks planning area. Acceptance will be at the discretion of the county.

6.

Private Open Space. Developments are encouraged to conform to usable open space provisions of the applicable zone. However, at a minimum, three hundred square feet of private, usable open space having a minimum of fifteen feet in depth and width shall be provided for each ground level dwelling unit PRD. Such private open space should be visible and accessible from the dwelling unit. When adjacent to common open space, such private open space is to serve as a buffer between dwelling units and common open space.

B.

Land Area and Dwelling Unit Computations. Open space, street area, etc., are computed as follows:

1.

Street Right-of-Way. Streets in a PRD shall be computed at twenty percent of the gross land area, regardless of the amount of land actually used for streets in the final design.

2.

Density. The density of the underlying zone governs unless a density increase is granted as provided in this chapter.

3.

Density Increase. The county may approve an increase in the dwelling unit density up to:

a.

In the low density district, fifteen percent;

b.

In the moderate density district, twenty percent;

c.

In the high density district, twenty-five percent; rounded to the nearest whole number, provided that the environmental and recreational amenities sought by this title are met.

4.

Development Formula. The computation of the number of dwelling units permitted, and other space requirements shall be as follows:

DU	= N/M × 1.2 (1.2 is the incentive factor)
G	Gross land area in square feet
S	Street area (i.e., twenty percent of G) in square feet
DU	Number of dwelling units
M	Minimum land area per dwelling unit
N	Net buildable site (G-S) in square feet

 

Example: In a hypothetical five acre site in the moderate density residential district, thirty-two dwelling units are permitted under conventional development procedures, assuming a minimum lot area of five thousand four hundred forty-five square feet, no dedication for other public use, and twenty percent of the land area dedicated for public right-of-way. The calculations are as follows:

G	= 5 acres = 217,800 square feet, gross land area
S	= 20% of G = 43,560 square feet of public R.O.W.
G-S	= 174, 240 square feet
DU	= 174,240/5,445 = 31.6 = 32 dwelling units

 

On the same five acre site, under PRD procedure, thirty-eight dwellings are permitted using the formula shown below:

DU	= N/M × 1.2
N	= G-S = 217,800 - 43,560 = 174,240 square feet
M	= 5,445 square feet minimum lot area
DU	= 174,240/5,445 × 1.2 = 38.4 = 38 dwelling units

 

C.

Landscaping Required. For applicable landscaping requirements, see Chapter 21.80.

(Ord. 11274 § 1 (part), 1996; Ord. No. 15390, § 1(Att. A, § T), 11-29-2016)