HomeMy WebLinkAboutUtilities 2016-09-13 Item 2C - Review - NPDES: Surface Water Low Impact Development Code Update (TMC Title 18 "Zoning")City of Tukwila
Allan Ekberg, Mayor
INFORMATIONAL MEMORANDUM
TO: Utilities Committee JJ
FROM: Bob Giberson, Public Works Director IPA
BY: Greg Villanueva, NPDES Coordinator
CC: Mayor Ekberg
DATE: September 9, 2016
SUBJECT: National Pollutant Discharge Elimination System (NPDES)
Project NO. 99341210
Low Impact Development Code Update — TMC Title 18
ISSUE
Review new LID code updates to Tukwila Municipal Code (TMC) Title 18 - Zoning.
BACKGROUND
The City's National Pollutant Discharge Elimination System (NPDES) Phase II permit requires
the City to review, revise, and make effective their local development related codes, rules
standards, or other enforceable documents to incorporate and require Low Impact Development
(LID) principles and LID Best Management Practices no later than December 31, 2016. As part
of this effort, the City's consultant, Otak, and staff from various departments reviewed all
development codes to determine which required updating to facilitate LID implementation and
remove barriers. TMC Title 18 — Zoning was determined to not be consistent with Department of
Ecology requirements and requires updating.
ANALYSIS
Staff, working with Otak, identified LID code updates that needed to be inserted into Title 18 —
Zoning. Draft amendments to this code have been made in strikeout & underline in codified
format for review and comment by the Planning Commission.
FINANCIAL IMPACT
No financial impact.
RECOMMENDATION
Utilities Committee approval to forward the proposed changes to TMC Title 18 — Zoning to the
Planning Commission for review and comment. Final amendments, in Ordinance form, will
return to Utilities Committee and full Council for final approval and adoption in the 4th Quarter of
2016.
Attachments: Draft Zoning Ordinance (codified version).
W: \PW Eng \ PROJECTS \\- DR Projects \NPDES Program (99341210)\2015 2017 Capacity Grant \Otak LID Gap Analysis \Info Memo 2016 UC LID Code Update RDL2 sb.doc
CHAPTER 1 8.0 6
DEFINITIONS
18.06.586 Native Vegetation
"Native vegetation" means plant species, other than noxious
weeds, that are indigenous to the coastal region of the Pacific
Northwest and that reasonably could be expected to have
occurred naturally on the site. Examples of these plant species
include Douglas fir, westem hemlock, western red cedar, alder,
big -leaf maple, vine maple, willow, elderberry, salmonberry,
salal, sword fern, foam flower, and fireweed.vegetation with a
Southern British Columbia, not including cultivars._
(Ord. 2347 §21, 2011)
CHAPTER 18.20
RESIDENTIAL COMMERCIAL CENTER
(RCC) DISTRICT
18.20.080 Basic Development Standards
Development within the Residential Commercial Center
District shall conform to the following listed and referenced
standards:
RCC BASIC DEVELOPMENT STANDARDS
Lot area, minimum
5,000 sq. ft.
Lot area per unit (multi - family),
minimum
3,000 sq. ft.
Setbacks to yards (min.):
• Front
20 feet
• Second front
10 feet
• Sides
5 feet
• Sides, if any portion of the
yard is within 50 feet of LDR,
MDR, HDR
10 feet
• Rear
10 feet
Height, maximum
3 stories or 35 feet
Landscape requirements (minimum): All setback areas shall be
landscaped. Required landscaping may include a mix of plant
materials, bioretention facilities, pedestrian amenities and
features, outdoor cafe -type seating and similar features,
subject to approval. See Landscape, Recreation,
Recycling /Solid Waste Space chapter for further requirements
• Front
20 feet
• Second front
10 feet
• Sides, if any portion of the
yard is within 50 feet of LDR,
MDR, HDR
10 feet
• Rear, if any portion of the
yard is within 50 feet of LDR,
MDR, HDR
10 feet
Recreation space
200 sq. ft. per dwelling unit
(1,000 sq. ft. min.)
Off- street parking:
• Residential
See TMC Chapter 18.56,
Off- street Parking & Loading
Regulations
• Accessory dwelling unit
See Accessory Use section
of this chapter
• Office, minimum
3 per 1,000 sq. ft.
usable floor area
• Retail, minimum
2.5 per 1,000 sq. ft.
usable floor area
• Other uses
See TMC Chapter 18.56,
Off- street Parking & Loading
Regulations
Performance Standards: Use, activity and operations within a
structure or a site shall comply with (1) standards adopted by the
Puget Sound Air Pollution Control Agency for odor, dust, smoke
and other airborne pollutants, (2) TMC Chapter 8.22, "Noise ", and,
(3) adopted State and Federal standards for water quality and
hazardous materials. In addition, all development subject to the
requirements of the State Environmental Policy Act, RCW 43.21 C,
shall be evaluated to determine whether adverse environmental
impacts have been adequately mitigated.
(Ord. 1976 §39, 2001; Ord. 1872 §3, 1999;
Ord. 1758 §1 (part), 1995)
24
CHAPTER 18.28
TUKWILA URBAN CENTER
(TUC) DISTRICT
18.28.070 Structure Height
A. The minimum and maximum height of a structure
shall be as specified by District or modified by a special height
overlay. See Table 3, "District Standards."
1. Structures oriented to Baker Boulevard shall
have an average height at least as high as the minimum listed
in Table 18 -3, "District Standards."
B. Pond Edge Height Limit.
1. Development located within 150 feet of the edge
of Tukwila Pond is not eligible for incentive height increases.
2. The maximum height in this location shall be as
specified by District.
C. Public Frontage Improvement Height Incentive.
1. As an incentive to provide public frontage
improvements and/or new streets that are not otherwise
required under this code, allowable structure heights may be
increased to the limits as specified for each District as shown
in Table 18 -3, "District Standards," when:
a. Developers construct public frontage
improvements along their parcel frontages on existing streets,
constructed to the standards of this code; or
b. Developers construct new 20 foot wide half
streets with one side of public frontage improvements,
constructed to the standards of this code; or
c. The existing sidewalk width and configuration
along a parcel's frontage meets or exceeds the public frontage
standard and, when averaged, the landscape width and street
tree spacing meet the required public frontage standard.
Additional sidewalk width may substitute for an equal area of
landscaping.
d. In order to take advantage of this incentive,
the public frontage improvements must start and stop at
property boundaries, intersections or traffic signals and
transition safely to neighboring conditions.
2. The public frontage height incentive will be
applied proportionally to parcels with more than one frontage
based on the following:
a. Each frontage will be evaluated separately
based on its Corridor Type's public frontage standards.
b. The height bonus will be applied to a
percentage of the total building footprint(s) on site based on
the percentage of the parcel's total public frontage that, when
averaged, meets the public frontage standard. For example,
when averaged, if one of a parcel's two similar length
frontages meets the corridor's public frontage standard, then
50% of the total building footprint on site is eligible for the
height incentive.
D. Multi - Family Height Incentive.
1. As an incentive to construct residential dwelling
units, allowable structure heights may be increased to the
limits specified in Table 18 -3, "District Standards."
2. Structures may be completely residential or
mixed use, with residential uses comprising at least half of the
occupied floor area of the building.
E. Structured Parking Height Incentive
1. As an incentive to reduce impervious cover
associated with parking lots and increase areas of native
vegetation, allowable structure heights may be increased to
the limits specified in Table 18 -3, "District Standards," when:
a. Developers place a minimum of 80 percent of
the minimum required parking stalls within structured parking
(transferred parking); and
b. Developers restore as a native growth
retention area an area equal to 40 percent of the area that
otherwise would have been needed to construct the
transferred parking as a surface lot.
2. In order to take advantage of this incentive, the
native growth retention area must meet specifications of the
native vegetated landscape of the Surface Water Design
Manual, adopted in accordance with TMC Chapter 14.30 and
must be set aside by a covenant, easement, or tract and
preserved and maintained for the life of the project.
€F. Structures qualify for increased height as set forth in
Table 18 -3, "District Standards," when integrating any of the
following combination of height incentives:
1. In the TUC -TOD District, allowable structure
heights may be increased to 115 feet for developments that
meet the requirements of two of the three available height
incentives: both -the frontal improvement, and-multi-family , or
structured parking height incentive requirement.
2. In the TUC -TOD District, allowable structure
heights may be increased to 115 feet for developments that
achieve a LEED certification of silver or higher and meet either
the requirements of one of the three available height
incentives: the frontal improvement or multi - family or
structured parking height incentive requirement,.
3. In the TUC -TOD District, allowable structure
heights may be increased to 115 feet for developments that
meet the multi - family height incentive requirements and make
at least 20% of the residential units affordable per the
standards in WAC 365- 196 -870. For rental units, affordability
is set at 50% of the county median family income, adjusted for
family size. For owner - occupied units, affordability is set at
80% of the county median family income, adjusted for family
size.
(Ord. 2443 §8, 2014)
18.28.240 General Landscaping
A. The provisions herein are applicable to setbacks,
public frontage areas, open space, and other areas on-
premises. These regulations address plant materials and
design, visibility, irrigation, landscape plans, utility and service
areas.
B. General Landscaping Requirements.
1. Plant Materials.
a. A mix of evergreen trees and evergreen
shrubs shall be used to screen blank walls.
25
b. All plant material shall meet the most recent
American Standards for Nursery Plant Stock (ANSI Z60.1).
c. Evergreen trees shall be a minimum of 6 feet
in height at time of planting.
d. Deciduous trees shall be a minimum 2.5 inch
caliper six inches off the ground when installed.
e. Shrubs shall be at least 18 inches in height at
time of planting.
f. Existing vegetation may be used to meet the
perimeter landscaping requirements. All significant trees
located within any required perimeter landscape area that are
not dead, dying, or diseased and that do not pose a safety
hazard as determined by the City or a qualified arborist shall
be retained and protected during construction with temporary
fencing or other enclosure, as appropriate to the site. The
area designated for protection will vary based on the tree's
diameter, species, age, and the characteristics of the planted
area. Property owners may be required to furnish a report by
an International Society of Arborist (ISA) certified arborist to
document a tree's condition. The Director may require that an
ISA certified arborist be retained to supervise tree protection
during construction. Grade changes around existing trees are
to be avoided whenever possible.
g. New plant materials shall include native
species or non - native species that are drought tolerant and
have adapted to the climatic conditions of the Puget Sound
Region. There must be a diversity of tree and shrub genus
and species in the site landscaping, taking into account
species in existing development around the site.
h. No species that are listed on the State or
King County noxious weed lists may be planted.
i. Plant materials shall be selected that
reinforce the landscape design concept, and are appropriate
to their location in terms of hardiness, tolerance to urban
conditions, maintenance needs and growth characteristics.
Large and medium canopy tree species are required, except
where there is insufficient planting area (due to proximity to a
building, street light, above ground or underground utility line,
etc.).
2. Visibility.
a. Design of new landscaping and maintenance
of existing landscaping shall consider Crime Prevention
Through Environmental Design (CPTED) principals and
visibility for safety and views. Appropriate plant species shall
be specified to avoid the need for excessive maintenance
pruning. Trees along the street frontages, as they mature,
shall be limbed up to a minimum height of 6 feet (8 feet where
they extend over sidewalks) to allow adequate visibility and
clearance for vehicles. Trees may be pruned to improve
views of signage and entryways by using such techniques as
windowing, thinning, and limbing -up. However, no more than
1/4 of the canopy may be removed within any 2 -year period,
and the crown should be maintained to at least 2/3 the height
of the tree. All pruning shall be done in accordance with ANSI
Standard A -300 specifications. Trees may not be topped for
any reason. Trees may only be pruned to lower their height to
prevent interference with an overhead utility or electrical line,
with prior approval by the Director.
b. Landscaping shall not obstruct views from or
into the driveway, sidewalk or street. Landscape design shall
allow for surveillance from streets and buildings and avoid
creating areas that might harbor criminal activity.
c. Landscaping at crosswalks and other
locations where vehicles and pedestrians intersect must not
block pedestrians' and drivers' views.
d. Evergreen shrubs and trees shall 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.
3. Soil Preparation and Planting.
a. For trees planted in sidewalks and parking
lots, Cornell University CU- Structural Soils must be used to a
preferred depth of 36 inches, to promote tree root growth and
provide structural support to the paved area. Minimum soil
volumes for tree roots shall be 750 square feet per tree (see
specifications and sample plans for CU- Structural Soils).
Trees and other landscape materials shall be directly planted
into a planting mix, approved by the Director, that is installed
on top of the structural soils.
b. For soil preparation in bioretention areas,
existing soils must be protected from compaction, and
bioretention soil media must be prepared in accordance with
Bioretention Soil Media Standard Specifications from the
Surface Water Design Manual, adopted in accordance with
TMC Chapter 14.30 to promote a proper functioning
bioretention system. These specifications shall be adhered to
regardless of whether a stormwater permit is required from the
City.
tic. For all other plantings, soils must be
prepared for planting in accordance with specifications to
restore soil moisture holding capacity in accordance with TMC
Chapter 16.54, GradinqBMP T5.13, "Post Construction Soil
Quality and Depth," from the Washington Department of
Washington (or as amended ), regardless of whether a
stormwater permit is required by the City.
ed. The applicant will be required to schedule an
inspection by the City of the planting areas prior to planting to
ensure soils are properly prepared.
de. Installation of landscape plants must comply
with best management practices including:
(1) Planting holes that are the same depth
as the size of the root ball and 2 times wider than the size of
the root ball.
(2) Root balls of potted and balled and
burlapped (B &B) plants must be loosened and pruned as
necessary to ensure there are no encircling roots prior to
planting. At least the top 2/3 of burlap and all straps or wire
baskets are to be removed from B &B plants prior to planting.
(3) The top of the root flare, where the
roots and the trunk begin, should be about one inch from the 26
surrounding soil. The root ball shall not extend above the soil
surface.
(4) If using mulch around trees and
shrubs, maintain at least a 3 -inch mulch -free ring around the
base of the plant trunks and woody stems of shrubs. If using
mulch around groundcovers until they become established,
mulch shall not be placed over the crowns of perennial plants.
4. Irrigation.
a. The intent of this standard is to ensure that
plants will survive the critical establishment period when they
are most vulnerable due to lack of watering.
b. All required plantings must be served by a
permanent automatic irrigation system.
(1) Irrigation shall be designed to
conserve water by using the best practical management
techniques available. These techniques may include, but not
be limited to: drip irrigation to minimize evaporation loss,
moisture sensors to prevent irrigation during rainy periods,
automatic controllers to insure proper duration of watering,
sprinkler head selection and spacing designed to minimize
overspray, and separate zones for turf and shrubs and for full
sun exposure and shady areas to meet watering needs of
different sections of the landscape.
(2) Exceptions to the irrigation
requirement may be approved by the Director, such as
xeriscaping (i.e., low water usage plantings), plantings
approved for low impact development techniques, established
indigenous plant material, or landscapes where natural
appearance is acceptable or desirable to the City. However,
those exceptions will require temporary irrigation until
established.
5. Landscape Plan Requirements.
a. A Washington State licensed landscape
architect shall prepare and stamp the landscape plans in
accordance with the standards herein. Detailed plans for
landscaping and screening shall be submitted with plans for
building and site improvements. Included in the plans shall be
type, quantity, spacing and location of plants and materials;
typical planting details; and the location of irrigation systems.
Underground and at- ground utilities shall be shown on the
plans so that planting conflicts are avoided.
b. Installation of the landscaping and screening
shall be completed and a Landscaping Declaration submitted
by the owner or owner's agent prior to issuance of the
Certificate of Occupancy. If necessary due to weather
conditions or construction scheduling, the installation may be
postponed to the next planting season if approved by the
Director and stated on the building permit. A performance
assurance device equal to 150% of the cost of the labor and
materials must be provided to the City before the deferral is
approved.
6. Parking Lots.
a. Setback and Perimeter Landscaping:
(1) Surface parking lots shall set back a
minimum of five feet from any open space, building fagade, or
Corridor back of sidewalk. The setback shall be designed and
planted with:
(a) 1 evergreen shrub per 4 linear feet
of property line, excluding curb cuts.
(b) Sufficient live groundcovers of
varying heights, colors and textures to cover, within 3 years,
100% of the yard area not needed for trees and shrubs.
Groundcover must be planted with a minimum spacing of 12
inches on center for 4 -inch pots and 18 inches on center for 1-
gallon pots. If turf grass is being used as the groundcover, a
3 -foot diameter ring of bark mulch is required around any tree.
(2) Surface parking lots shall be buffered
from adjacent residential development with heavy screening in
the side and rear setback areas.
b. Interior Parking Lot Landscaping:
(1) For surface parking lots adjacent to
public or private streets, a minimum of 20 square feet of
interior parking lot landscaping is required for each parking
stall. In the Workplace District, a minimum of 15 square feet
per stall is required for warehouse and light industrial uses.
(2) For surface parking lots located behind
buildings or otherwise screened from public or private streets
or public spaces, a minimum of 10 square feet of interior
parking lot landscaping is required for each parking stall.
(3) Flexibility is allowed for the layout of
parking lots and landscaped areas, but the goal is to provide
shade from trees that are evenly distributed throughout the
parking lot. Planting trees in continuous, landscaped planting
strips between rows of parking is encouraged. This approach
may also be combined with surface water management
design. For parking lots adjacent to public or private streets, if
landscape islands are designed into the parking lot layout to
divide continuous rows of parking stalls, they must be placed
at minimum spacing of every 10 parking spaces. For parking
areas located behind buildings or otherwise screened from
public or private streets or public spaces, if landscape islands
are used, they shall be placed at a minimum of one island
every 15 parking stalls.
(4) Landscape islands must be a minimum
of 6 feet wide and a minimum of 100 square feet in area. All
landscaped areas must be protected from damage by vehicles
(curbs, tire stops, other techniques).
(5) Landscape islands shall be placed at
the ends of each row of parking to protect parked vehicles
from turning movements of other vehicles.
(6) A minimum of one large- canopy
evergreen or deciduous tree or two medium - canopy trees are
required for every 100 square feet of landscaped island, with
the remaining area to contain a combination of shrubs, living
groundcover, and mulch (see Figure 18 -47).
27
Figure 18 -47: A single tree planted with no other materials and
little room for viability is not acceptable.
7. Utility and Service Areas. Utility easements
and other similar areas between property lines and curbing
shall be landscaped and /or treated with dust and erosion
control planting or surfacing. Trees proposed under overhead
transmission lines shall be approved by the City on a case -by-
case basis.
8. Street Trees in the Public Frontage.
a. Street tree spacing in the public frontage
shall be as specified in the applicable Corridor Standards. For
smaller stature trees (those with canopies at maturity of less
than 20 feet), spacing should be every 20 feet. For larger
canopy trees, spacing should be wider as appropriate to the
mature spread of the tree. Spacing will also need to consider
sight vision distance at intersections, driveway locations, and
utility conflicts.
b. Street trees in the public frontage shall be
planted to at least the following spacing standards:
(1) At least 3.5 feet back from the face of
the curb and with an approved root barrier installed on the
curb side.
(2) At least 5 feet from underground utility
lines.
(3) At least 10 feet from power poles.
(4) At least 7.5 feet from driveways.
(5) At least 3 feet from pad - mounted
transformers (except 10 feet in front for access).
(6) At least 4 feet from fire hydrants and
connections.
c. When used, tree grates and landscaped tree
wells shall be a minimum 36 square feet in size (6' x 6'). Tree
grates are not encouraged, but when used grates must have
easily removable rings so that sections of grate can be
removed incrementally as the tree matures. Tree well size
may be adjusted to comply with ADA standards on narrower
sidewalks. Root barriers must be installed at curb face. See
TMC Section 18.28.240.B.3, "Soil Preparation and Planting,"
for structural soil requirements.
d. Planting and lighting plans shall be
coordinated so that trees are not planted in locations where
they would obstruct existing or planned street or site lighting,
while maintaining appropriate spacing and allowing for their
size and spread at maturity.
9. Maintenance and Pruning.
a. Any landscaping required by this chapter
shall be retained and maintained by the property owner for the
life of the project in conformance with the intent of the
approved landscape plan and this chapter. Maintenance shall
include keeping all planting areas free of weeds and trash and
replacing any unhealthy or dead plant materials.
b. Pruning of trees is only allowed for the health
of the tree, to maintain sight distances or sight lines into
commercial areas, or if interfering with overhead utilities. All
pruning must be done in accordance with American National
Standards Institute (ANSI) A -300 specifications. No tree
planted by a property owner or the City to fulfill landscape
requirements, or any existing tree, may be topped or removed
without prior approval from the City. If a tree is topped or
removed without approval, it shall be replaced with a new tree
that meets the intent of this chapter within 120 days or the
property owner will be subject to code enforcement action per
TMC Chapter 8.45. Options at the Director's discretion are to
require replacement of the tree with a new tree of similar
species that will achieve a similar canopy size at maturity,
replace the tree with multiple smaller diameter trees of an
appropriate species (only if there are limitations on space or
conflicts with utility infrastructure), and /or require an in -lieu fee
for off -site tree replacement.
C. General Landscaping Considerations.
1. Plant Materials.
a. Drought resistant species are encouraged in
order to minimize irrigation requirements, except where site
conditions within the required landscape areas ensure
adequate moisture for growth.
b. The mature size of selected tree species
should be suitable to lot size, the scale of adjacent structures,
and the proximity to utility lines.
c. 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.
d. All trees should be selected and located so
they will not obstruct views to showroom windows and building
signage as they mature.
e. Evergreen landscaping (Figure 18 -48) is
appropriate for screening utility vaults, loading docks and
some storage areas. (Also see TMC Section 18.52.040 for
screening outdoor storage areas.)
28
Figure 18 -48: Using evergreen landscaping to screen utilities
f. Species selection is very important in
grouped plantings (Figure 18 -49). Drought tolerant species
are strongly recommended and monoculture plantings are
discouraged. Low maintenance cost and low replacement
costs are two advantages of planting drought tolerant species
in grouped configurations. Low (24 -30 inches) shrubs,
perennial or groundcover plantings that provide a superior
degree of separation between the sidewalk and street at
reduced maintenance costs may be used.
Figure 18 -49: Examples of landscaped tree wells
2. Design.
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. 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.
(Ord. 2443 §25, 2014)
29
CHAPTER 18.52
LANDSCAPE, RECREATION,
RECYCLING /SOLID WASTE
SPACE REQUIREMENTS
18.52.020 Perimeter Landscaping Requirements by
Zone District
A. In the various zone districts of the City, landscaping
in the front, rear and side yards shall be provided as
established by the various zone district chapters of this title.
These requirements are summarized in the following table,
except for Tukwila Urban Center (TUC) requirements, which
are listed in TMC Chapter 18.28.
ZONING
DISTRICTS
FRONT YARD
(SECOND
FRONT)
LANDSCAPE
TYPE FOR
FRONTS
SIDE
YARD
REAR
YARD
LANDSCAPE
TYPE FOR
SIDE /REAR
LDR
(for uses other
than dwelling
units
152
Type!
10
10
Type
MDR
151,2
Type!
10
10
Type 1
HDR
151,2
Type!
10
10
Type 1
MUO
15 (12.5)2
Type 17
54
54
Type 17
0
15 (12.5)2
Type 17
54
54
Type 17
RCC
20 (10)2'3
Type 17
54
10
Type 11
NCC
54
Type 17
04
04
Type 11
RC
10
Type!
54
04
Type 11$
RCM
10
Type 1
54
04
Type 11$
TUC — See TMC Chapter 18.28
C /LI
12.55
Type 16
55
05
Type 11$
LI
12.52
Type 11
04
04
Type III
HI
12.52
Type 11
04
04
Type III
MIC /L
55
Type 11
05
05
Type III
MIC /H
55
Type 11
05
05
Type III
TVS
152'3
Type 11
04
04
Type III
ISO
159'2
Type 1
010
010
Type III
Notes:
1. Minimum required front yard landscaped areas in
the MDR and HDR zones may have up to 20% of their
required landscape area developed for pedestrian and transit
facilities upon approval as a Type 2 special permission
decision. Bioretention may also serve as 20% of the required
front yard landscaping for MDR and HDR zones.
2. In order to provide flexibility of the site design
while still providing the full amount of landscaping required by
code, the front yard landscape width may be divided into a
perimeter strip and one or more other landscape areas
between the building and the front property line, if the
perimeter strip is a minimum of 10 feet and the landscape
materials are sufficient to provide landscaping along the
perimeter and screening of the building mass.
3. Required landscaping may include a mix of plant
materials, pedestrian amenities and features, outdoor cafe -
type seating and similar features, subject to approval as a
Type 2 special permission decision. Bioretention may also be
used as required landscaping for RCC, TVS, and TS0
districts. Required plant materials will be reduced in
proportion to the amount of perimeter area devoted to
pedestrian oriented space.
4. Increased to 10 feet if any portion of the yard is
within 50 feet of LDR, MDR or HDR.
5. Increased to 15 feet if any portion of the yard is
within 50 feet of LDR, MDR or HDR.
30
6. Increased to Type II if the front yard contains
truck loading bays, service areas or outdoor storage.
7. Increased to Type II if any portion of the yard is
within 50 feet of LDR, MDR or HDR.
8. Increased to Type III if any portion of the yard is
within 50 feet of LDR, MDR or HDR.
9. Only required along public streets.
10. Increased to 10 feet if adjacent to residential
uses or non -TSO zoning.
B. The landscape perimeter may be averaged if the total
required square footage is achieved, unless the landscaping
requirement has been increased due to proximity to LDR,
MDR or HDR. Landscape perimeter averaging may be
allowed as a Type 2 special permission decision if all of the
following criteria are met:
1. Plant material can be clustered to more
effectively screen parking areas and blank building walls.
2. Perimeter averaging enables significant trees or
existing built features to be retained.
3. Perimeter averaging is used to reduce the
number of driveways and curb cuts and allow joint use of
parking facilities between neighboring businesses.
4. Width of the perimeter landscaping is not
reduced to the point that activities on the site become a
nuisance to neighbors.
5. Averaging does not diminish the quality of the
site landscape as a whole.
(Ord. 2442 §1, 2014; Ord. 2251 §61, 2009; Ord. 2235 §13, 2009;
Ord. 1872 §14 (part), 1999)
18.52.030 Perimeter Landscape Types
A. Type I landscape perimeter.
1. Purpose is to enhance Tukwila's streetscapes,
provide a light visual separation between uses and zoning
districts, screen parking areas, and allow views to building
entryways and signage.
2. Plant materials shall consist of the following:
a. One tree for each 30 lineal feet of required
perimeter excluding curb cuts; and
b. One shrub for each 7 lineal feet of required
perimeter excluding curb cuts or a planted berm at least 24
inches high; and
c. Living groundcover to cover 90% of the
landscape area within three years.
3. Bioretention may be used as a Type I landscape
perimeter, provided that the intent of the screen is achieved.
To support bioretention facility function and plant survival,
flexibility in plant materials and placement shall be allowed,
provided that public safety is not compromised.
B. Type II landscape perimeter.
1. Purpose is to enhance Tukwila's streetscapes,
provide a moderate visual separation between uses and
zoning districts, screen blank building walls and parking areas,
and allow views to building entryways and signage.
2. Plant materials shall consist of the following:
a. One tree for each 20 lineal feet of required
perimeter excluding curb cuts; and
b. One shrub for each 5 lineal feet of required
perimeter excluding curb cuts; and
c. Living groundcover to cover 90% of the
landscape area within three years.
3. Bioretention may be used as a Type II
landscape perimeter, provided that the intent of the screen is
achieved. To support bioretention facility function and plant
survival, flexibility in plant materials and placement shall be
allowed, provided that public safety is not compromised.
C. Type III landscape perimeter.
1. Purpose is to provide extensive visual separation
between industrial areas and nearby residential areas.
2. Plant materials shall consist of the following:
a. One tree per 20 lineal feet of required
perimeter excluding curb cuts; and
b. Shrubs to provide a solid planting screen with
a height of five to eight feet or a solid wooden fence or
masonry wall to be approved by the Community Development
Director; and
c. Living groundcover to cover 90% of the
landscape area within three years.
D. Plant material requirements.
1. Plants shall meet the current American Standard
for Nursery Stock (American Nursery and Landscape
Association — ANLA), and shall be healthy, vigorous and well -
formed, with well - developed, fibrous root systems, free from
dead branches or roots. Plants shall be free from damage
caused by temperature extremes, lack of or excess moisture,
insects, disease, and mechanical injury. Plants in leaf shall be
well foliated and of good color. Plants shall be habituated to
outdoor environmental conditions (hardened -off).
2. A mix of evergreen trees and evergreen shrubs
shall be used to screen blank walls.
3. Deciduous trees shall be used to allow visual
access to entryways, signage and pedestrian use areas.
4. Evergreen shrubs shall be used to screen
parking lots along street frontages.
5. In perimeters located adjacent to residential
zones 75% of trees and shrubs shall be evergreen.
6. Evergreen trees shall be a minimum of 6 feet in
height at time of planting.
7. Deciduous trees shall have at least a 2 inch
caliper at time of planting, determined according to the
American Standard for Nursery Stock.
8. Shrubs shall be at least 18 inches in height at
time of planting.
9. No plants listed on the current King County
Noxious Weed list may be used.
10. Existing vegetation may be used to meet the
requirements of this chapter. All significant trees located
within any required perimeter landscaping area which are not
dead, dying, or diseased and which do not pose a safety
hazard as determined by the Community Development
Director shall be retained.
31
11. The classification of plant material as trees,
shrubs and evergreens shall be as listed in the Hortus Third, A
Concise Dictionary of Plants Cultivated in the U.S. and
Canada.
12. Plant material requirements for bioretention
facilities shall be in accordance with the City's bioretention
plant list.
(Ord. 2251 §62, 2009; Ord. 1872 §14 (part), 1999)
18.52.035 Interior Parking Lot Landscaping
Requirements
Landscaping within parking areas shall be provided as
shown below.
1. Requirements for each distinctly separate
parking area within the LDR zone for uses other than dwelling
units, and in the MDR and HDR zones:
a. For areas with up to 20 parking stalls per
parking area, no interior landscaping is required.
b. For areas with 21 - 40 parking stalls per
parking area, 7 square feet of interior landscape area is
required for each parking stall.
c. For areas with more than 40 parking stalls
per parking area, 12 square feet of interior landscape area is
required for each parking stall (see Multi - Family Design
Guidelines, Site Planning Section, No. 31, for the normal 15
square feet to be provided).
d. All parking areas shall have a perimeter
landscape strip a minimum of 2 feet wide with an average
width of 5 feet.
2. Requirements for parking lots within the 0,
MUO, RCC, and NCC zones:
a. For lots with up to 20 parking stalls, no
interior landscaping is required.
b. For lots with 21 - 40 parking stalls, a
minimum of 10 square feet of interior landscape area is
required for each parking stall over 20.
c. For lots with more than 40 parking stalls, a
minimum of 200 square feet of interior landscape area plus 15
square feet for each parking stall over 40 is required. For
areas placed behind buildings or otherwise screened from
streets, parks and City trails the interior landscape
requirement is reduced to a minimum of 200 square feet plus
10 square feet for each parking stall over 40.
3. Requirements for parking lots within the RC,
RCM, C /LI, TSO and TVS zones:
a. For areas adjacent to public or private
streets, a minimum of 15 square feet of landscaping is
required for each parking stall.
b. For areas placed behind buildings or
otherwise screened from streets, parks and City trails a
minimum of 10 square feet of interior landscape area is
required for each parking stall.
4. Planting Standards:
a. Interior landscape islands shall be distributed
to break up expanses of paving. Landscaped areas shall be
placed at the ends of each interior row in the parking area,
with no stall more than 10 stalls or 100 feet from a landscape
area. Landscaped areas and planting islands may contain
bioretention.
b. The minimum size for interior parking lot
planting islands is 100 square feet.
c. Planting islands shall be a minimum of 6 feet
in any direction and generally the length of the adjacent
parking space.
d. Raised curbs or curb stops shall be used
around the landscape islands to prevent plant material from
being struck by automobiles. Where bioretention is used, curb
cuts shall be placed to allow stormwater runoff from adjacent
pavements to enter the bioretention system.
e. A minimum of 1 evergreen or deciduous tree
is required per landscape island, with the remaining area to
contain a combination of shrubs, living groundcover and
mulch.
(Ord. 2442 §2, 2014; Ord. 2251 §63, 2009; Ord. 2235 §14, 2009;
Ord. 1872 §14 (part), 1999)
18.52.050 Landscape Plan Requirements
A. A Washington State licensed landscape architect
shall prepare and stamp the landscape plans in accordance
with the standards herein. Detailed plans for landscaping and
screening shall be submitted with plans for building and site
improvements. Included in the plans shall be type, quantity,
spacing and location of plants and materials, site preparation
and specifications for soils and mulches, location of all
overhead and underground utilities (so as to avoid conflicts
with proposed planting locations), typical planting details and
the location of irrigation systems.
B. Installation of the landscaping and screening shall be
completed and a Landscaping Declaration submitted by the
owner or owner's agent prior to issuance of the certificate of
occupancy. If necessary, due to weather conditions or
construction scheduling, the installation may be postponed to
the next planting season if approved by the Community
Development Director and stated on the building permit. A
performance assurance device equal to 150% of the cost of
the labor and materials must be provided to the City before the
deferral is approved. The property owner shall keep all
planting areas free of weeds and trash and replace any
unhealthy or dead plant materials for the life of the project in
conformance with the intent of the approved landscape plan
and TMC Section 8.28.180. Any landscaping required by this
chapter shall be retained and maintained for the life of the
project. Additionally, topping or removal of required trees is
prohibited. Only trees that pose a danger or are diseased, as
determined by an ISA certified arborist, shall be allowed to be
removed. Any illegal removal of required trees shall be
subject to obtaining a tree permit and replacement with trees
that meet or exceed the functional value of the removed trees.
C. Landscape Plans that include a bioretention facility
shall be submitted to the Public Works Director in addition to
the Community Development Director.
32
(Ord. 2368 §53, 2012; Ord. 2251 §65, 2009; CHAPTER 18.56
Ord. 1971 §19, 2001; Ord. 1872 §14 (part), 1999)
OFF - STREET PARKING AND
LOADING REGULATIONS
18.56.040 General Requirements
Any required off - street parking and loading facilities shall
be developed in accordance with the following standards:
1. Location. Any on- premises parking area which
contains parking stalls located more than 1,000 feet from the
principal use shall require Board of Architectural Review
approval for the entire parking lot.
2. MINIMUM PARKING. Minimum parking area
dimensions for surface and structured parking facilities shall
be as provided in Figure 18 -6. Standard and compact parking
stalls shall be allowed a two -foot landscaping overhang to
count towards the stall length.
3. TANDEM PARKING SPACES. In the MDR and
HDR zones, tandem spaces (where one car is parked directly
behind another) will be allowed for each three bedroom and
1/3 of all two bedroom units. No more than 1/3 of all project
parking spaces may be tandem and all tandem parking
spaces will be designed for full size rather than compact size
vehicles based on the dimensions in Figure 18 -6.
4. PARKING AREA AND PARKING AREA
ENTRANCE AND EXIT SLOPES. The slope of off - street
parking spaces shall not exceed 5 %. The slope of entrance
and exit driveways providing access for off - street parking
areas and internal driveway aisles without parking stalls shall
not exceed 15 %.
5. DRIVEWAYS AND MANEUVERABILITY.
a. Adequate ingress to and egress from each
parking space shall be provided without moving another
vehicle and without backing more than 50 feet.
b. Turning and maneuvering space shall be
located entirely on private property unless specifically
approved by the Public Works Director and the Board of
Architectural Review.
c. All parking spaces shall be internally
accessible to one another without reentering adjoining public
streets.
d. When off - street parking is provided in the
rear of a building and a driveway or lane alongside the
building provides access to rear parking area, such driveway
shall require a minimum width of twelve feet and a sidewalk of
at least a three -foot section, adjoining the building, curbed or
raised six inches above the driveway surface.
e. Ingress and egress to any off - street parking
lot shall not be located closer than 20 feet from point of
tangent to an intersection.
f. The Public Works Director or the Community
Development Director may require ingress separate from an
egress for smoother and safer flow of traffic.
6. The Director may require areas not designed or
approved for parking to be appropriately marked and /or signed
to prevent parking.
7. SURFACE.
33
a. The surface of any required off - street parking
or loading facility shall be paved with asphalt, concrete or
other similar approved material (s) and shall be graded and
drained as to dispose of all surface water, but not across
sidewalks.
b. All traffic- control devices, such as parking
stripes designating car stalls, directional arrows or signs, bull
rails, curbs and other developments shall be installed and
completed as shown on the approved plans.
c. Paved parking areas shall use paint or similar
devices to delineate car stalls and direction of traffic.
d. Where pedestrian walks are used in parking
lots for the use of foot traffic only, they shall be curbed or
raised six inches above the lot surface.
e. Wheel stops shall be required on the
periphery of parking lots so cars will not protrude into the
public right -of -way, walkways, off the parking lot or strike
buildings. Wheel stops shall be two feet from the end of the
stall of head -in parking.
f. The use of permeable pavement is the
preferred material for parking surfaces, and any parking stalls
provided in excess of the required minimum required off- street
parking spaces shall use permeable pavement where
technically feasible in accordance with the Surface Water
Design Manual, adopted in accordance with TMC Chapter
14.30.
8. PARALLEL PARKING STALLS. Parallel parking
stalls shall be designed so that doors of vehicles do not open
onto the public right -of -way.
9. OBSTRUCTIONS. No obstruction which would
restrict car door opening shall be permitted within five feet of
the centerline of a parking space.
10. LIGHTING. Any lighting on a parking lot shall
illuminate only the parking lot, designed to avoid undue glare
or reflection on adjoining premises.
11. CURB -CUTS. All parking areas shall have
specific entrance and /or exit areas to the street. The width of
access roads and curb -cuts shall be determined by the Public
Works Director. The edge of the curb -cut or access road shall
be as required by the Public Works Director for safe
movement of vehicles or pedestrians. Curb -cuts in single -
family districts shall be limited to a maximum of 20 feet in
width and the location shall be approved by the Public Works
Director.
12. PARKING STALL. Parking stalls shall not be
used for permanent or semi - permanent parking or storage of
trucks or materials.
(Ord. 2368 §54, 2012; Ord. 2251 §66, 2009;
Ord. 1795 §3 (part), 1997; Ord. 1758 §1 (part), 1995)
34
Off - Street Parking Area Dimensions
TM 18.56.040
A
B
C
D
E
F
Parking
Angie
Staff
Width
Stall
Depth
Aisle Width
Curb
Length
Unit Width
1 -way traffic
2 -way traffic
1 -way traffic
2 -way traffic
0°
8*
8*
12
20
20*
28*
36*
8.5
8,5
12
20
23
29
37
30°
8*
15*
11
20
16*
41*
54*
8.5
17
11
20
17
45
54
9
17.5
11
20
18
46
55
20
9.5
18
11
19
47
56
45°
8*
17*
12.5
20
11.5*
46.5*
54*
8.5
19.5
12.5
20
12
51.5
59
9
20
12
20
12.7
52
60
9.5
20
12
20
13.4
52
—GO-
60°
8*
18*
17.5*
20
9.2*
53.5
56*
8.5
21
17.5
20
9,8
59.5
62
9
21
17
20
10.4
59
62
9,5
21
16.5
20
11
58.5
62
90°
8*
16*
24
25
8*
56*
57*
8.5
19
24
25
8.5
62
63
9
19
23
24
9
61
62
9.5
19
22
24
9.5
60
62
*These figures are for use with compact cars only. Any bays that contain
combined compact and normal spaces shall be designed for normal spaces.
Curb
Length (E)
-- stall width
cr depth
(B or C)
Aisle or Street
•
Parking
Angle
tAf
Aisle (D
Stall
Width
Stall Depth
Perpendicular
to Aisle (C)
\v
Curb Length (E)
f
•
Unit
Width
(F)
Angled Parking
Parallel Parking
Figure 18 -6
Off-Street Parking
Area Dimensions
35
Table 18 -3 District Standards:
18.28.070 Structure Height'
Minimum Height
25 ft fronting
Baker BI.
25 ft fronting
Baker BI.
n/a
Maximum Height without Incentives
Frontal Improvement Height Incentive
Multi - Family Height Incentive
Structured Parking Height Incentive
85 ft
45 ft
115 ft, or214ft
w /in 300 ft of
Tukwila Pkwy
& Southcenter
Pkwy
70 ft, 115' if
combined with MF,
LEED, Structured
Parking or
Affordable
Housing Incentive
45 ft
70 ft, no increase
wlin
150 ft of Pond
edge
115 ft, or214ft
w /in 300 ft of
Tukwila Pkwy
& Southcenter
Pkwy
70 ft, 115' if
combined with
Frontal Imp.,
LEED, Structured
Parking or
Affordable
Housing Incentive
115 ft, or214ft
w /in 300 ft of
Tukwila Pkwy
& Southcenter
Pkwy
70 ft, 115' if
combined with
Frontal Imp., MF,
LEED or
Affordable Housing
Incentive
70 ft, no increase
wlin
150 ft of Pond
edge
n/a
n/a
45 ft
45 ft
n/a
n/a
n/a
70 ft
River adjacent
parcels only
70 ft, no increase
w/in
150 ft of Pond
edge
18.28.080 Maximum Block Face Length
Provision of New Streets 850 ft max2
18.28.090 Permitted Corridor Types for New Streets
700 ft max
700 ft max
900 ft max
900 ft max
Pedestrian Corridor
Regional
permitted
permitted
Corridor
District Standards
Center
TOD
Pond District
Comm.
Workplace
18.28.070 Structure Height'
Minimum Height
25 ft fronting
Baker BI.
25 ft fronting
Baker BI.
n/a
Maximum Height without Incentives
Frontal Improvement Height Incentive
Multi - Family Height Incentive
Structured Parking Height Incentive
85 ft
45 ft
115 ft, or214ft
w /in 300 ft of
Tukwila Pkwy
& Southcenter
Pkwy
70 ft, 115' if
combined with MF,
LEED, Structured
Parking or
Affordable
Housing Incentive
45 ft
70 ft, no increase
wlin
150 ft of Pond
edge
115 ft, or214ft
w /in 300 ft of
Tukwila Pkwy
& Southcenter
Pkwy
70 ft, 115' if
combined with
Frontal Imp.,
LEED, Structured
Parking or
Affordable
Housing Incentive
115 ft, or214ft
w /in 300 ft of
Tukwila Pkwy
& Southcenter
Pkwy
70 ft, 115' if
combined with
Frontal Imp., MF,
LEED or
Affordable Housing
Incentive
70 ft, no increase
wlin
150 ft of Pond
edge
n/a
n/a
45 ft
45 ft
n/a
n/a
n/a
70 ft
River adjacent
parcels only
70 ft, no increase
w/in
150 ft of Pond
edge
18.28.080 Maximum Block Face Length
Provision of New Streets 850 ft max2
18.28.090 Permitted Corridor Types for New Streets
700 ft max
700 ft max
900 ft max
900 ft max
Pedestrian Corridor
permitted
permitted
Walkable Corridor
permftted
permitted
Neighborhood Corridor
permitted
permitted
permitted
permitted3
Urban Corridor
permitted
permitted
permitted
Commercial Corridor
permitted
permitted
Workplace Corridor
permitted
permitted
Tukwila Pond Esplanade
permitted
Pedestrian Walkway
permitted
18.28.100 Side and Rear Setbacks
Side and Rear Yards 5ft4
5ft4
5 ft4
5 ft
5 ft
18.28.110 Side and Rear Landscaping
Side and Rear Yards
18.28.220 Special Corner Feature
Requirements
5ft4
5 ft4
Oft Oft
( 5ft4
Special Corner Feature on Building
permitted
permitted
permitted
1) Portions of the building that extend above the primary building mass, such as non- habitable space (clock towers, roof -top cupolas, elevator
and mechanical equipment enclosures), unenclosed space (roof deck trellises, gazebos), and other special architectural features, shall not
exceed the maximum height requirement by more than 20 feet, provided they are set back a minimum of 10 feet from the edge of the roof
(see also TMC 18.50.080).
2) Does not apply to Freeway Frontage Corridors
3) Permitted adjacent to residential uses.
4) May be waived as part of design review if Building and Fire Code requirements are met.
36