HomeMy WebLinkAboutORD 61791
CITY OF RENTON, WASHINGTON
ORDINANCE NO. 6179
AN ORDINANCE OF THE CITY OF RENTON, WASHINGTON, AMENDING SECTIONS
4-3-050, 4-11-030, 4-11-040, AND 4-11-190 OF THE RENTON MUNICIPAL CODE;
AND AMENDING THE FOLLOWING SUBSECTIONS OF SECTION 4-3-050: 4-3-050.A,
4-3-050.B.1, 4-3-050.C, 4-3-050.D.3, 4-3-050.D.5.c, 4-3-050.E.3, 4-3-050.E.5, 4-3-
050.E.6, 4-3-050.F, 4-3-050.G, 4-3-050.H.3, 4-3-050.I.1, 4-3-050.I.3, 4-3-050.J.2.a,
4-3-050.J.4, 4-3-050.L.1.a, 4-3-050.L.1.b, 4-3-050.L.1.g, 4-11-190.B; AMENDING
CRITICAL AREAS REGULATIONS INCLUDING ADDING STANDARDS FOR
CONSISTENCY WITH BEST AVAILABLE SCIENCE AND NEW DEFINITION IN SECTION
4-11-030; AUTHORIZING CORRECTIONS, PROVIDING FOR SEVERABILITY, AND
ESTABLISHING AN EFFECTIVE DATE.
WHEREAS, the Revised Code of Washington (RCW) 36.70A.060 and RCW 36.70A.170
require counties and cities to designate critical areas and adopt regulations to protect them; and
WHEREAS, RCW 36.70A.130(1)(a) requires counties and cities to periodically review, and
if necessary, revise development regulations regarding critical areas according to deadlines set
forth in RCW 36.70A.130(4) and (5); and
WHEREAS, the RCW 36.70A.172 requires counties and cities to include the best available
science in developing policies and development regulations to protect the functions and values
of critical areas to give special consideration to conservation or protection measures to preserve
or enhance anadromous fisheries; and
WHEREAS, in accordance with the requirement for the inclusion of best available science
and the requirement in RCW 36.70A.130 to periodically review development regulations, the
City has conducted a review of its existing critical area regulations together with a review of best
available science; and
WHEREAS, this matter was duly referred to the Planning Commission for investigation
and study, and the matter was considered by the Planning Commission; and
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WHEREAS, the Planning Commission held a public hearing on September 17, 2025,
considered all relevant matters, and heard all parties in support or opposition, and subsequently
forwarded a recommendation to the City Council; and
WHEREAS, pursuant to RCW 36.70A.106, on September 25, 2025, the City notified the
State of Washington of its intent to adopt amendments to its development regulations;
NOW, THEREFORE, THE CITY COUNCIL OF THE CITY OF RENTON, WASHINGTON, DO
ORDAIN AS FOLLOWS:
SECTION I. All portions of the Renton Municipal Code (RMC) in this ordinance that are not
shown in strikethrough and underline edits or are not explicitly repealed herein remain in effect
and unchanged.
SECTION II. Section 4-3-050.A of the RMC is amended as follows:
The purposes of this Section are to:
1. Manage development activities to protect environmental quality, and promote
diversity of species, and habitat within the City by regulating critical areas, including
wetlands, critical aquifer recharge areas, fish and wildlife habitat conservation areas,
frequently flooded areas, and geologically hazardous areas as defined by the Growth
Management Act and chapter 4-11 RMC;
2. Ensure that activities in or affecting critical areas do not threaten public safety,
cause nuisances, or destroy or degrade critical area functions and values;
3. Prevent the loss of critical area acreage and functions and strive for a net gain over
present conditions through restoration where feasible;
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4. Assist or further the implementation of the policies of the Growth Management
Act, the State Environmental Policy Act, and the City of Renton Comprehensive Plan;
5. Provide City officials with information to evaluate, approve, condition, or deny
public or private development proposals with regard to critical area impacts;
6. Protect the public life, health, safety, welfare, and property by minimizing and
managing the adverse environmental impacts of development within and abutting critical
areas;
7. Protect the public from:
a. Avoidable monetary losses due to maintenance and replacement of public
facilities and utilities, property damage, public mitigation of avoidable impacts, and
public emergency rescue and relief operations; and
b. Potential litigation on improper construction practices occurring in critical
areas;
8. Reduce the potential for damage to life and property from abandoned coal mines,
and return the land to productive uses;
9. Maintain, to the extent practicable, a stable tax base by providing for the sound use
and development of areas of flood hazard areas so as to minimize future flood blight
areas; and
10. Protect riparian habitat and ecological processes in order to provide for bank and
channel stability, sustained water supply, flood storage, recruitment of woody debris, leaf
litter, nutrients, sediment and pollutant filtering, shade, shelter, and other functions that
are important to both fish and wildlife.
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SECTION III. Section 4-3-050.B.1 of the RMC is amended as follows:
1. Lands to Which These Regulations Apply and Non-regulated Lands: The following
critical areas are regulated by this Section. Multiple development standards may apply to
a site feature based upon overlapping critical area(s) and/or critical area classifications:
a. Flood hazard areas. Includes floodways and channel migration zones.
b. Geologic Hazards Geologically Hazardous Areas. Steep slopes (must have a
minimum vertical rise of fifteen feet (15')), landslide hazards, erosion hazards, seismic
hazards, and/or coal mine hazards or on sites within fifty feet (50') of steep slopes,
landslide hazards, erosion hazards, seismic hazards, and/or coal mine hazards
classified under RMC 4-3-050.G.5 which are located on abutting or adjacent sites.
c. Fish and Wildlife Habitat Conservation Areas.
d. Streams and Lakes. All applicable requirements of this Section apply to Class F,
Np, and Ns water bodies, as defined in subsection G7 of this Section RMC 4-3-050.G.2
or on sites within one hundred feet (100') of Class F, Np, and Ns water bodies, except
Type S water bodies, inventoried as “Shorelines of the State,” are not subject to this
Section, and are regulated in RMC 4-3-090, Shoreline Master Program Regulations,
and RMC 4-9-190, Shoreline Permits.
e. Wellhead Protection Critical Aquifer Recharge Areas.
f. Wetlands, Categories I, II, III, and IV or on sites within two hundred feet (200')
the buffers of Category I, II, III, and IV wetlands.
Wetlands created or restored as a part of a mitigation project are regulated wetlands.
Regulated wetlands do not include those artificial wetlands intentionally created from
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non-wetland sites, including, but not limited to, irrigation and drainage ditches, grass-
lined swales, canals, detention facilities, wastewater treatment facilities, farm ponds, and
landscape amenities, or those wetlands created after July 1, 1990, that were
unintentionally created as a result of the construction of a road, street, or highway.
g. Sites Separated from Critical Areas, Nonregulated: As determined by the
Administrator, these regulations may not apply to development proposed on sites
that are separated from critical areas by pre-existing, intervening, and lawfully
created structures, roads, or other substantial existing improvements. For the
purposes of this Section, the intervening lots/parcels, roads, or other substantial
improvements shall be found to:
i. Separate the subject upland property from the critical area due to their
height or width; and
ii. Substantially pPrevent or impair delivery of most functions from the subject
upland property to the critical area. Such determination and evidence shall be
included in the application file. Public notification shall be given as follows:
(a) For applications that are not subject to notices of application pursuant
to Chapter 4-8 RMC, notice of the buffer determination shall be given by
posting the site and notifying parties of record, if any, in accordance with
Chapter 4-8 RMC.
(b) For applications that are subject to notices of application, the buffer
determination or request for determination shall be included with notice of
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application. Upon determination, notification of parties of record, if any, shall
be made.
SECTION IV. Section 4-3-050.C of the RMC is amended as follows:
1. Permit Required:
a. Development or Alteration: Prior to any development or alteration of a
property containing a critical area as defined in subsection B of this Section, entitled
Applicability, the owner or designee must obtain a development permit, critical area
permit, and/or letter of exemption. No separate critical area permit is required for a
development proposal which requires development permits or which has received a
letter of exemption. A separate critical area permit is not required for development
proposals that already require other development permits and/or have received a
letter of exemption.
b. Operating and Closure Permits – Wellhead Protection Areas: Wellhead
Protection Areas operating permit and closure permit requirements are contained in
RMC 4-9-015, Aquifer Protection Areas Permits.
2. Letter of Exemption:
a. Flood Hazard Areas, Geologically Hazardous Areas, Fish and Wildlife Habitat
Conservation Areas, Streams and Lakes, Wellhead Protection Areas, Wetlands:
Except in the case of public emergencies, all other exemptions in this subsection C
may require that a letter of exemption be obtained from the Administrator prior to
construction or initiation of activities.
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b. Applicability of Requirements to Exempt Activities: Exempt activities provided
with a letter of exemption may intrude into the critical area or required buffer subject
to any listed conditions or requirements. Exempt activities do not need to comply with
mitigation ratios of subsection J of this Section RMC 4-3-050.J unless required in
exemption criteria.
c. Reports and Mitigation Plans Required: A critical area report, and/or
enhancement or mitigation plan shall be required pursuant to subsections F and L of
this SectionRMC 4-3-050.F and 4-3-050.L, unless otherwise waived by the
Administrator.
d. Administrator Findings: In determining whether to issue a letter of exemption
for activities listed in this subsection C, the Administrator shall find that:
i. The activity is not prohibited by this or any other provision of the Renton
Municipal Code or State or Federal law or regulation;
ii. The activity will be conducted using best management practices as specified
by industry standards or applicable Federal agencies or scientific principles;
iii. Impacts are minimized and, where applicable, disturbed areas are
immediately restored;
iv. Where water body or buffer disturbance has occurred in accordance with
an exemption during construction or other activities, revegetation with native
vegetation shall be required;
v. If a hazardous material, activity, and/or facility that is exempt pursuant to
this Section has a significant or substantial potential to degrade groundwater
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quality, then the Administrator may require compliance with the Wellhead
Protection Area requirements of this Section otherwise relevant to that hazardous
material, activity, and/or facility. Such determinations will be based upon site
and/or chemical-specific data.
3. Exemptions – Critical Areas and Buffers: Exempt activities are those that are not
anticipated to have a significant impact on the structure or function of a critical area. All
exempt activities must be conducted in a manner that avoids and minimizes adverse
impacts to critical areas. Exempt activities are listed in the following table. If an “X”
appears in a box, the listed exemption applies in the specified critical area and required
buffer. If an “X” does not appear in a box, then the exemption does not apply in the
particular critical area or required buffer. Where utilized in the following table the term
“restoration” means returning the subject area back to its original state or better
following the performance of the exempt activity, as determined by the City. Activities
taking place in critical areas and their associated buffers and listed in the following table
are exempt from the applicable provisions of this Section, provided a letter of exemption
has been issued. Whether the exempted activities are also exempt from permits will be
determined based upon application of chapters 4-8 and 4-9 RMC, or other applicable
sections of the Renton Municipal Code. All activities within shoreline jurisdiction are
subject to Shoreline Master Program Regulations in RMC 4-3-090 and 4-10-095. All
exempt activities must comply with state requirements to ensure no net loss of critical
area functions and values.
Table 4-3-050.C.3 Exemption Table
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EXEMPT ACTIVITIES – PERMITTED WITHIN CRITICAL AREAS AND ASSOCIATED BUFFERS
EXEMPT ACTIVITY
Flood
Hazard
Areas
Geologically
Hazardous
Areas
Fish and
Wildlife
Habitat
Conservation
Areas
Streams
and
Lakes:
Type F,
Np, & Ns
Wellhead
Protection
Areas
Wetlands
a. Conservation, Enhancement, Education and Related Activities:
i. Natural
Resource/Habitat
Conservation or
Preservation2
X X X X X1 X
ii. Enhancement
activities as defined in
chapter 4-11 RMC
X X X X X
iii. Approved
Restoration/Mitigation3 X X X X X1 X
b. Research and Site Investigation:
i. Nondestructive
Education and
Research
X X X X X1 X
ii. Site Investigative
Work4 X X X X X1 X
c. Agricultural, Harvesting, Vegetation Management:
i. Harvesting Wild
Foods5 X X X X X1 X
ii. Existing/Ongoing
Agricultural Activities6 X X X X X
iii. Dangerous High-
RiskTrees7 X X X X8 X1 X8
d. Surface Water:
i. New Surface Water
Discharges9 X X X
ii. Modification of
existing Regional
Stormwater Facilities10
X
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EXEMPT ACTIVITIES – PERMITTED WITHIN CRITICAL AREAS AND ASSOCIATED BUFFERS
EXEMPT ACTIVITY
Flood
Hazard
Areas
Geologically
Hazardous
Areas
Fish and
Wildlife
Habitat
Conservation
Areas
Streams
and
Lakes:
Type F,
Np, & Ns
Wellhead
Protection
Areas
Wetlands
iii. Flood Hazard Areas
Reduction11 X X
iv. Storm Drainage
Piping12 X
e. Public and Private Roads, Parks, Public and Private Utilities18:
i. Relocation of Existing
Utilities out of Critical
Area and Buffer13
X X X X X1 X
ii. Maintenance,
Operation, and Repair
of existing Parks, Trails,
Roads, Facilities, and
Utilities, and the
Construction of New
Trails14
X X X X X X
iii. Utilities, Traffic
Control, Walkways,
Bikeways Within
Existing, Improved
Right-of-Way or
Easements15
X X X X
iv. Modification of
Existing Utilities and
Streets by Ten Percent
(10%) or Less16
X X17 X17
v. Construction and
Maintenance of
Pedestrian Skybridge
Structures twenty feet
(20’) and higher from
the surface
X X X X X X
f. Temporary Wetland Impacts:
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EXEMPT ACTIVITIES – PERMITTED WITHIN CRITICAL AREAS AND ASSOCIATED BUFFERS
EXEMPT ACTIVITY
Flood
Hazard
Areas
Geologically
Hazardous
Areas
Fish and
Wildlife
Habitat
Conservation
Areas
Streams
and
Lakes:
Type F,
Np, & Ns
Wellhead
Protection
Areas
Wetlands
i. Temporary Wetland
Impacts19 X X
g. Maintenance and Construction – Existing Uses and Facilities:
i. Remodeling,
Replacing, Removing
Existing Structures,
Facilities, and
Improvements20
X X X X
ii. Maintenance and
Repair – Any Existing
Public or Private Use21
X X X X
iii. Modification of an
Existing Residential
Structure Single
Family22
X X X X X
iv. Existing Activities23 X X X X X
h. Emergency Activities:
i. Emergency
Activities24, 25, 26, 27 X X X X X1 X
i. Hazardous Materials:
i. Federal or State
Preemption28 X1
ii. Use of Materials with
No Risk29 X1
Footnotes:
1. If a hazardous material, activity, and/or facility that is exempt pursuant to this Section
has a significant or substantial potential to degrade groundwater quality, then the Administrator
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may require compliance with the Wellhead Protection Area requirements of this Section
otherwise relevant to that hazardous material activity and/or facility.
2. Conservation or preservation of soil, water, vegetation, fish and other wildlife. Within
shoreline jurisdiction this includes watershed restoration projects as defined in WAC
173-27-040(2)(o) or projects to improve fish or wildlife habitat or fish passage approved by the
Washington State Department of Fish and Wildlife as described in WAC 173-27-040(2)(p).
3. Any critical area and/or buffer restoration or other mitigation activities which have
been approved by the City. Within shoreline jurisdiction this includes watershed restoration
projects as defined in WAC 173-27-040(2)(o) or projects to improve fish or wildlife habitat or fish
passage approved by the Washington State Department of Fish and Wildlife as described in WAC
173-27-040(2)(p).
4. Site investigative work necessary for land use application submittals such as surveys,
soil logs, percolation tests, and other related activities. Investigative work shall not disturb any
more than five percent (5%) of the critical area and required buffer. In every case, impacts shall
be minimized and disturbed areas shall be immediately restored at a one-to-one (1:1) ratio.
Within shoreline jurisdiction, this includes the marking of property lines or corners on state-
owned lands, when such marking does not significantly interfere with the normal public use of
the surface water. Limitations on site exploration and investigative activities are defined in WAC
173-27-040(2)(m) for properties within shoreline jurisdiction.
5. The harvesting of wild foods in a manner that is not injurious to natural reproduction
of such foods and provided the harvesting does not require tilling of soil, planting of crops, or
alteration of the critical area.
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6. Existing and ongoing agricultural activities including farming, horticulture, aquaculture
and/or maintenance of existing irrigation systems. Activities on areas lying fallow as part of a
conventional rotational cycle are part of an ongoing operation; provided, that the agricultural
activity must have been conducted within the last five (5) years. Activities that bring a critical
area into agricultural use are not part of an ongoing operation. Maintenance of existing legally
installed irrigation, ditch, and pipe systems is allowed; new or expanded irrigation, ditch, outfall,
or other systems are not exempt. If it is necessary to reduce the impacts of agricultural practices
to critical areas, a farm management plan may be required based on the King County
Conservation District’s Farm Conservation and Practice Standards, or other best management
practices. Within shoreline jurisdiction practices normal or necessary for farming are defined in
WAC 173-27-040(2)(e).
7. Removal of non-native invasive ground cover or weeds listed by King County Noxious
Weed Board or other government agency or dangerous high-risk trees, as defined in chapter 4-
11 RMC, which have been approved by the City and certified dangerous by a licensed landscape
architect, or certified arborist, selection of whom to be approved by the City based on the type
of information required.
8. Limited to cutting of dangerous high-risk trees; such hazardous trees shall be retained
as large woody debris in critical areas and/or associated buffers, where feasible.
9. New surface water discharges in the form of dispersion trenches, outfalls and
bioswales are allowed within the outer twenty five percent (25%) of the buffer of a Category III
or IV wetland only provided that: the discharge meets the requirements of the Drainage and
Water Quality (Surface Water) Standards (RMC 4-6-030); no other location is feasible; and will
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not degrade the functions or values of the wetland or stream. Where differences exist between
these regulations and RMC 4-6-030, these regulations will take precedence.
10. Modifications to existing regional stormwater management facilities operated and
maintained under the direction of the City Surface Water Utility that are designed consistent with
the current version of the Washington State Department of Ecology Stormwater Management
Manual or meeting equivalent objectives.
11. Implementation of public flood hazard areas reduction and public surface water
projects, where habitat enhancement and restoration at a one-to-one (1:1) ratio are provided,
and appropriate Federal and/or State authorization has been received.
12. Installation of new storm drainage lines in any geologic hazard area when a
geotechnical report clearly demonstrates that the installation would comply with the criteria
listed in RMC 4-3-050.J.1 and that the installation would be consistent with each of the purposes
of the critical area regulations listed in RMC 4-3-050.A. Also, to qualify for the exemption, the
report must propose appropriate mitigation for any potential impacts identified in the report.
13. Relocation out of critical areas and required buffers of natural gas, cable,
communication, telephone and electric facilities, lines, pipes, mains, equipment and
appurtenances (not including substations), with an associated voltage of fifty five thousand
(55,000) volts or less, only when required by a local governmental agency, and with the approval
of the City. Disturbed areas shall be restored.
14. Normal and routine maintenance, operation and repair of existing parks, trails,
streets, roads, rights-of-way and associated appurtenances, facilities and utilities where no
alteration or additional fill materials will be placed other than the minimum alteration and/or fill
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needed to restore those facilities or to construct new trails to meet established safety standards.
The use of heavy construction equipment shall be limited to utilities and public agencies that
require this type of equipment for normal and routine maintenance and repair of existing utility
structures and rights-of-way. In every case, critical area and required buffer impacts shall be
minimized and disturbed areas shall be restored during and immediately after the use of
construction equipment.
15. Within existing and improved public road rights-of-way or easements, installation,
construction, replacement, operation, overbuilding or alteration of all- natural gas, cable,
communication, telephone and electric facilities, lines, pipes, mains, equipment or
appurtenances, traffic control devices, illumination, walkways and bikeways. If activities exceed
the existing improved area or the public right-of-way, this exemption does not apply. Where
applicable, restoration of disturbed areas shall be completed. Within shoreline jurisdiction the
exemption also applies to any project with a certification from the Governor pursuant to
chapterRCW 80.50 RCW.
16. Overbuilding (enlargement beyond existing project needs) or replacement of existing
utility systems and replacement and/or rehabilitation of existing streets, provided:
a. The work does not increase the footprint of the structure, line, or street by more
than ten percent (10%) within the critical area and/or buffer areas, and occurs in the
existing right-of-way boundary or easement boundary.
b. Restoration shall be conducted where feasible. Compensation for impacts to
buffers shall include enhancement of the remaining buffer area along the impacted area
where there is enhancement opportunity. Restoration and enhancement of wetlands
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shall consider Wetland Mitigation in Washington State, Part 1: Agency Policies and
Guidance, Version 2 (Ecology Publication No. 21-06-003, April 2021) or as amended
hereafter.
c. The Administrator determines that, based on best judgment, a person would not:
(i) be able to meaningfully measure, detect, or evaluate insignificant effects; or (ii) expect
discountable effects to occur.
d. This exemption allows for ten percent (10%) maximum expansion total, life of the
project. After the ten percent (10%) expansion cap is reached, future improvements are
subject to all applicable provisions of this Section.
17. Exemption is not allowed in Category I wetlands.
18. Maintenance activities, including routine vegetation management and essential tree
removal, and removal of non-native invasive vegetation or weeds listed by the King County
Noxious Weed Board or other government agency, for public and private utilities, road rights-of-
way and easements, and parks.
19. Temporary disturbances of a wetland due to construction activities that do not
include permanent filling may be permitted; provided, that there are no permanent adverse
impacts to the critical area or required buffer, and areas temporarily disturbed are restored at a
one-to-one (1:1) ratio. Category I wetlands and Category II forested wetlands shall be enhanced
at a two-to-one (2:1) ratio in addition to being restored consistent with Wetland Mitigation in
Washington State, Part 1: Agency Policies and Guidance, Version 2 (Ecology Publication No. 21-
06-003, April 2021) or as amended hereafter. For Fish and Wildlife Habitat Conservation Areas,
this exemption applies only to Category I wetlands.
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20. Remodeling, restoring, replacing or removing structures, facilities and other
improvements in existence or vested on the date this Section becomes effective and that do not
meet the setback or buffer requirements of this Section provided the work complies with the
criteria in RMC 4-10-090.
21. Normal and routine maintenance and repair of any existing public or private uses and
facilities where no alteration of the critical area and required buffer or additional fill materials
will be placed. The use of heavy construction equipment shall be limited to utilities and public
agencies that require this type of equipment for normal and routine maintenance and repair of
existing utility or public structures and rights-of-way. In every case, critical area and required
buffer impacts shall be minimized and disturbed areas shall be restored during and immediately
after the use of construction equipment. Normal maintenance and repair for structures within
shoreline jurisdiction is defined by WAC 173-27-040(2)(b).
22. Additions and alterations of an existing single family residence residential structure
and/or garage (attached or detached); provided, that the addition/alteration does not increase
the footprint of the structure lying within the critical area or buffer; and provided, that no portion
of the addition/alteration occurs closer to the critical area or required buffers than the existing
structure unless the structure or addition can meet required buffers. Existing or rebuilt accessory
structures associated with single family dwelling a residential structure and rebuilt with the same
footprint such as fences, gazebos, storage sheds, and play housesplayhouses are exempt from
this Section. New accessory structures may be allowed when associated with single-family
dwellings a residential structure such as fences, gazebos, storage sheds, play housesplayhouses,
and when built on and located in a previously legally altered area.
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23. Existing activities which have not been changed, expanded or altered, provided they
comply with the applicable requirements of chapter 4-10 RMC.
24. Emergency activities are those which are undertaken to correct emergencies that
threaten the public health, safety and welfare. An emergency means that an action must be
undertaken immediately or within a time frame too short to allow full compliance with this
Section, to avoid an immediate threat to public health or safety, to prevent an imminent danger
to public or private property, or to prevent an imminent threat of serious environmental
degradation. Within shoreline jurisdiction, emergency activities are defined by WAC
173-27-040(2)(d).
25. Emergency tree and/or ground cover removal by any City department or agency
and/or public or private utility involving immediate danger to life or property, substantial fire
hazards, or interruption of services provided by a utility.
26. Emergency activities in Wellhead Protection Areas: Public interest emergency use,
storage, and handling of hazardous materials by governmental organizations.
27. Temporary emergency exemptions shall be used only in extreme cases and not to
justify poor planning by an agency or applicant. Issuance of an emergency permit by the City does
not preclude the necessity to obtain necessary approvals from appropriate Federal and State
authorities. Notwithstanding the provisions of this Section or any other City laws to the contrary,
the Administrator may issue a temporary emergency exemption letter if the action meets the
requirements:
a. An unacceptable threat to life or severe loss of property will occur if an emergency
permit is not granted;
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b. The anticipated threat or loss may occur before a permit can be issued or modified
under the procedures otherwise required by this Section and other applicable laws;
c. Any emergency exemption letter granted shall incorporate, to the greatest extent
practicable and feasible but not inconsistent with the emergency situation, the standards
and criteria required for nonemergency activities under this Section.
d. The emergency exemption shall be consistent with the following procedural and
time requirements:
i. The emergency shall be limited in duration to the time required to complete the
authorized emergency activity; provided, that no emergency permit be granted for a
period exceeding ninety (90) days except as specified in RMC 4-3-050.C.
ii. Any critical area altered as a result of the emergency activity must be restored
within the ninety (90) day period, except that if more than ninety (90) days from the
issuance of the emergency permit is required to complete restoration, the emergency
permit may be extended to complete this restoration. For the purposes of this
subsection, “restoration” means returning the affected area to its state prior to the
performance of the emergency activity.
iii. Notice of the issuance of the emergency permit and request for public
comments shall be posted at the affected site(s) and City Hall no later than ten (10)
days after the issuance of the emergency permit. If significant comments are received,
the City may reconsider the permit.
iv. Expiration of Exemption Authorization: The emergency exemption
authorization may be terminated at any time without process upon a determination
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by the Administrator that the action was not or is no longer necessary to protect
human health or the environment.
28. Cleanups, monitoring, and/or studies undertaken under supervision of the
Washington Department of Ecology or the U.S. Environmental Protection Agency.
29. Use, storage, and handling of specific hazardous materials that do not present a risk
to the aquifer as determined and listed by the Department.
4. Exemptions – In Buffers Only: The activities listed in the following table are allowed
within critical area buffers, and are exempt from the applicable provisions of this Section,
provided a letter of exemption has been issued pursuant to this subsection C. If an “X”
appears in a box, the listed exemption applies in the specified buffer. If an “X” does not
appear in a box, then the exemption does not apply in the required buffer. Whether the
exempted activities are also exempt from permits will be determined based upon
application of chapters 4-8 and 4-9 RMC, or other applicable sections of the Renton
Municipal Code. All activities within shoreline jurisdiction are subject to Shoreline Master
Program Regulations in RMC 4-3-090 and 4-10-095.
Table 4-3-050.C.4 Exemption Table
EXEMPTIONS WITHIN CRITICAL AREA BUFFERS
EXEMPT
ACTIVITY
Flood
Hazard
Areas
Geologically
Hazardous
Areas
Fish and
Wildlife
Habitat
Conservation
Areas
Streams
and Lakes:
Types F, Np,
& Ns
Wellhead
Protection
Areas
Wetlands
a. Activities in Critical Area Buffers:
ORDINANCE NO. 6179
21
EXEMPTIONS WITHIN CRITICAL AREA BUFFERS
EXEMPT
ACTIVITY
Flood
Hazard
Areas
Geologically
Hazardous
Areas
Fish and
Wildlife
Habitat
Conservation
Areas
Streams
and Lakes:
Types F, Np,
& Ns
Wellhead
Protection
Areas
Wetlands
i. Trails and
Open
Space1
X X X X X X
ii.
Stormwater
Treatment
and Flow
Control
Facilities in
Buffer2
X
iii.
Stormwater
Conveyance
in Buffer3
X X X
Footnotes:
1. Walkways and trails, and associated open space in critical area buffers located on
public property, or where easements or agreements have been granted for such purposes on
private property. All of the following criteria shall be met:
a. The trail, walkway, and associated open space shall be consistent with the Parks,
Recreation, and Natural Areas Open Space Plan or Bike and Trails Master Plan. The City
may allow private trails as part of the approval of a site plan, subdivision, or other land
use permit approvals.
ORDINANCE NO. 6179
22
b. Trails and walkways shall be located in the outer twenty five percent (25%) of the
buffer, i.e., the portion of the buffer that is farther away from the critical area. Exceptions
to this requirement may be made for:
i. Trail segments connecting to existing trails where an alternate alignment is not
practical.
ii. Public access points to water bodies spaced periodically along the trail.
c. Enhancement of the buffer area is required where trails are located in the buffer.
Where enhancement of the buffer area abutting a trail is not feasible due to existing high-
quality vegetation, additional buffer area or other mitigation may be required consistent
with Wetland Mitigation in Washington State, Part 1: Agency Policies and Guidance,
Version 2 (Ecology Publication No. 21-06-003, April 2021), or as amended hereafter.
d. Trail widths shall be a maximum width of twelve feet (12') five feet (5'). Trails shall
be constructed of permeable materials which that protect water quality, allow adequate
surface water and ground water movements, do not contribute to erosion, are located
where they do not disturb nesting, breeding, and rearing areas, and are designed to avoid
or reduce the removal of trees. Impervious materials may be allowed if pavement is
required for handicappedADA or emergency access, or for safety, or if the trail is a
designated nonmotorized transportation route or makes a connection to an already
dedicated trail, or the materials reduces the potential for other environmental impacts.
e. Any crossing over a stream or wetland shall be generally perpendicular to the
critical area and shall be accomplished by bridging or other technique designed to
ORDINANCE NO. 6179
23
minimize critical area disturbance. It shall also be the minimum width necessary to
accommodate the intended function or objective.
2. Stormwater management facilities shall not be built within a critical area buffer except
as allowed in Reference 5, Wetlands Protection Guidelines of the City’s Surface Water Design
Manual. and shall require buffer enhancement or buffer averaging when they are sited in areas
of forest vegetation, provided the standard buffer zone area associated with the critical area
classification is retained pursuant to RMC 4-3-050G2, and is sited to reduce impacts between the
critical area and surrounding activities.
3. Necessary conveyance systems including stormwater dispersion outfall systems
designed to minimize impacts to the buffer and critical area, where the site topography requires
their location within the buffer to allow hydraulic function, provided the standard buffer zone
area associated with the critical area classification is retained pursuant to RMC 4-3-050.G.2, and
is sited to reduce impacts between the critical area and surrounding activities.
4. WAC 173-27-040(2)(g) defines and identifies the limitations on the construction of a
single family home and appurtenances. Single family residences and appurtenances must be
located landward of the ordinary high-water mark and the perimeter of a wetland. Based on the
results of a critical area report, and/or enhancement or mitigation plan, the City shall condition
development to require buffer enhancement or buffer averaging, site design that reduces
impacts between the critical area and surrounding activities, and a building setback.
SECTION V. Section 4-3-050.D.3 of the RMC is amended as follows:
3. Flood Hazard Areas:
ORDINANCE NO. 6179
24
a. DesignaƟon of the Floodplain Administrator: The Administrator is hereby
appointed to administer, implement, and enforce the provisions of this Sec Ɵon by
granƟng or denying development permits in accordance with its provisions. The
Floodplain Administrator may delegate authority to implement these provisions.
b. Enforcement: All development within special flood hazard areas and channel
migraƟon zones is subject to the terms of this SecƟon and other applicable
regulaƟons. The standards of this SecƟon are not intended to repeal, abrogate, or
impair any exisƟng easements, covenants, or deed restricƟons. However, where the
standards of this SecƟon and any other applicable regulaƟon, easement, covenant, or
deed restricƟon conflict or overlap, whichever imposes the more stringent restricƟons
shall prevail. These regulaƟons, and the various parts thereof, are hereby declared to
be severable. Should any standard of this SecƟon be declared by the courts to be
unconsƟtuƟonal or invalid, such decision shall not affect the validity of this SecƟon as
a whole, or any porƟon thereof, other than the secƟon so declared to be
unconsƟtuƟonal or invalid.
c. Basis for Establishing the Areas of Special Flood Hazard: The special flood
hazard areas idenƟfied by the Federal Insurance Administrator in a scien Ɵfic and
engineering report enƟtled “The Flood Insurance Study (FIS) for King County,
Washington and Incorporated Areas” dated August 19, 2020, and any revisions
thereto, with accompanying Flood Insurance Rate Maps (FIRMs), and any revisions
thereto, are hereby adopted by reference and declared to be a part of this Sec Ɵon.
The FIS and the FIRM are on file at City of Renton, 1055 South Grady Way, Renton,
ORDINANCE NO. 6179
25
WA 98057. The best available informaƟon for flood hazard area idenƟficaƟon as
outlined in subsecƟon D3f of this SecƟonRMC 4-3-050.D.3.f shall be the basis for
regulaƟon unƟl a new FIRM is issued that incorporates data uƟlized under subsecƟon
D3f of this SecƟonRMC 4-3-050.D.3.f.
d. InformaƟon to be Provided by Applicant: The applicant shall provide the
Administrator the following informaƟon:
i. The actual elevaƟon, in relaƟon to mean sea level, the North American
VerƟcal Datum of 1988 (NAVD 88), of the lowest floor (including basement) of all
new or substanƟally improved structures, and whether or not the structure
contains a basement where base flood elevaƟon data is provided through the
flood insurance study or required.
ii. For all new or substanƟally improved flood proofed structures:
(a) The applicant shall verify and have recorded the actual elevaƟon in
relaƟon to mean sea level, the North American VerƟcal Datum of 1988 (NAVD
88); and
(b) Flood elevaƟon cerƟficates shall be submiƩed by an applicant to the
Development Services Division prior to the building’s finished floor
construcƟon. Finished floor elevaƟon should be verified by a preconstrucƟon
elevaƟon cerƟficate at the Ɵme of construcƟon of a substanƟal structural
element of the finished floor (i.e., foundaƟon form for the concrete floor). An
as-built elevaƟon cerƟficate will be provided prior to issuance of final
occupancy.
ORDINANCE NO. 6179
26
iii. Where a structure is to be flood proofed, cer ƟficaƟon by a registered
professional engineer or architect that the flood proofing methods for any
nonresidenƟal structure meet flood proofing criteria in subsecƟon G4diii(b) of this
SecƟonRMC 4-3-050.G.d.iii.b;
iv. DescripƟon of the extent to which a watercourse will be altered or
relocated as a result of proposed development;
v. Where a structure is proposed in a V, V1-30, or VE zone, a V-zone design
cerƟficate;
vi. Where development is proposed in a floodway, an engineering analysis
indicaƟng no rise of the Base Flood ElevaƟon; and
vii. Any other such informaƟon that may be reasonably required by the
Floodplain Administrator in order to review the applicaƟon.
e. InformaƟon to be Obtained and Maintained:
i. Where base flood elevaƟon data is provided through the FIS, FIRM, or
required as in subsecƟon D3f of this SecƟonRMC 4-3-050.D.3.f, obtain and
maintain a record of the actual (as-built) elevaƟon (in relaƟon to mean sea level)
of the lowest floor (including basement) of all new or substanƟally improved
structures, and whether or not the structure contains a basement.
ii. For all new or substanƟally improved flood proofed nonresidenƟal
structures where base flood elevaƟon data is provided through the FIS, FIRM, or
as required in subsecƟon D3f of this SecƟonRMC 4-3-050.D.3.f:
ORDINANCE NO. 6179
27
(a) Obtain and maintain a record of the elevaƟon (in relaƟon to mean sea
level) to which the structure was flood proofed.
(b) Maintain the flood proofing cerƟficaƟons required in subsecƟon G4diii
of this SecƟon.
iii. CerƟficaƟon required by subsecƟon G4ei of this SecƟonRMC
4-3-050.G.4.e.i.
iv. Records of all variance acƟons, including jusƟficaƟon for their issuance.
v. Improvement and damage calculaƟons.
vi. Maintain for public inspecƟon all records pertaining to the provisions of this
SecƟon.
f. Use of Other Base Flood Data (in A and V Zones): When base flood elevaƟon
data has not been provided (in A or V zones) in accordance with subsecƟon D3c of this
SecƟonRMC 4-3-050.D.3.c, Basis for Establishing the Areas of Special Flood Hazard,
the Floodplain Administrator shall obtain, review, and reasonably uƟlize any base
flood elevaƟon and floodway data available from a federal, state, or other source, in
order to administer subsecƟon G4d of this SecƟonRMC 4-3-050.G.4.d, Specific
Standards, and subsecƟon G4e of this SecƟonRMC 4-3-050.G.4.e, AddiƟonal
RestricƟons within Floodways.
g. Basis for Establishing the Channel MigraƟon Zone: A channel migraƟon zone
for the Cedar River has been idenƟfied and mapped by King County in a report Ɵtled
Cedar River Channel MigraƟon Study, dated April 2015. The study shall be the basis
for regulaƟon unƟl the study or porƟons thereof are updated and accepted by the City,
ORDINANCE NO. 6179
28
or unless the City approves a mapping change pursuant to RMC 4-3-050.E.3.c, Channel
MigraƟon Zone DeterminaƟon.
i. At the request of a property owner or on its own iniƟaƟve, the department
may reassess and adjust the boundary of a completed CMZ map within a smaller
porƟon of the full CMZ study length as follows:
(a) A property owner may submit a criƟcal area study to the department
supporƟng the property owner’s request for a site-specific reassessment of the
CMZ boundary. The criƟcal area study shall be conducted using channel
migraƟon mapping methods and criteria specified in King County’s
DesignaƟon, ClassificaƟon and Mapping of Channel MigraƟon Zones Appendix
A: PreparaƟon of Channel MigraƟon Zone (CMZ) Study and Map.
(b) The department may reassess and adjust the boundary of CMZ or its
component hazard areas if it determines that the condiƟons within a specific
porƟon of an overall CMZ study area have changed to the extent that the
exisƟng mapped CMZ boundary is no longer accurate. The reassessment and
adjustment shall be made using mapping methods and criteria specified in King
County’s DesignaƟon, ClassificaƟon and Mapping of Channel MigraƟon Zones
Appendix A: PreparaƟon of Channel MigraƟon Zone (CMZ) Study and Map.
(c) If the department approves an adjustment to an exisƟng CMZ map
under RMC 4-3-050.D.3.g.i.a or b, the adjustment will be documented by City
of Renton staff in a leƩer and annotated porƟon of the adjusted CMZ map.
SECTION VI. Section 4-3-050.D.5.c of the RMC is amended as follows:
ORDINANCE NO. 6179
29
c. Geologically Hazardous Areas, Fish and Wildlife Habitat Conservation Areas,
Streams and Lakes, and Wetlands: The Administrator is authorized, pursuant to
subsection H of this Section, entitled Alterations To Critical Areas And/Or Buffers –
General Requirements, to make the following administrative allowances and
determinations:
i. Geologically Hazardous Areas:
(a) Waive independent review of geotechnical reports.
(b) Increase or decrease required buffer for very high landslide hazard
areas.
(c) Grant a modification for created slopes.
ii. Streams and Lakes:
(a) Approve proposals for buffer width reductions.
(b) Approve proposals for buffer width averaging.
iii. Wellhead Protection Areas:
(a) Issue operating and closure permits.
(b) Determine pipeline requirements.
(c) Determine if Zone 1 requirements should apply in Zone 2 of a Wellhead
Protection Area.
iv. Wetlands:
(a) Determine whether wetlands are unregulated.
(b) Extend the valid period of a wetland delineation.
ORDINANCE NO. 6179
30
(c) Approve proposals for buffer width reductions of up to twenty five
percent (25%).
(d) Approve proposals for buffer width averaging.
(e) Authorize other category level for created or restored wetlands.
(f) Waive requirements of this Section upon determination that all impacts
on wetlands would be mitigated as part of an approved area-wide wetlands
plan that, when taken as a whole over an approved schedule or staging of plan
implementation, will meet or exceed the requirements of this Section.
SECTION VII. Section 4-3-050.E.3 of the RMC is amended as follows:
3. Flood Hazard Areas:
a. Basic Map and Documentation Identifying Hazards: Flood hazard areas are
identified by the Federal Insurance Administration in a scientific and engineering
report entitled the Flood Insurance Study for the City of Renton, dated September 29,
1989, and any subsequent revision, with accompanying flood insurance maps which
are hereby adopted by reference and declared to be a part of this Section. The flood
insurance study is on file at the Public Works Department pursuant to RMC 4-3-
050.D.3.c, Basis for Establishing the Areas of Special Flood Hazard.
b. When Federal Insurance Study is Not Available: The Applicant shall obtain, for
City review, and reasonably utilization any base flood elevation and floodway data
available from a Federal, State or other source, in the following instances:
i. To administer subsection G of this SectionRMC 4-3-050.G when base flood
elevation data has not been provided in accordance with this subsection E.
ORDINANCE NO. 6179
31
ii. To identify flood hazard areas that will be regulated; until a new Flood
Insurance Rate Map is issued which incorporates the data utilized under
subsection D of this SectionRMC 4-3-050.D.
SECTION VIII. Section 4-3-050.E.5 of the RMC is amended as follows:
5. Streams and Lakes: Water class shall be determined in accordance with subsection
G7a of this SectionRMC 4-3-050.G.2.a.
a. Reclassification: The reclassification of a water body to a lower class (i.e., F to Np,
or Np to Ns, etc.) requires Administrator acceptance of a stream or lake study, followed
by an legislativeadministrative amendment to the map in this subsection E prior to its
effect. The reclassification of a water body to a higher class (i.e., Ns to Np, Np to F, or F to
S) requires either: Administrator acceptance of a stream or lake study or consultation with
the Washington Department of Fish and Wildlife, followed by an legislativeadministrative
amendment to the map in this Section.
b. Salmonid Migration Barriers: For the purposes of classifying or reclassifying
water bodies, features determined by the Administrator to be salmonid migration
barriers pursuant to the definition in RMC 4-11-190 shall be mapped. The
Administrator shall prepare and update the map as appropriate.
SECTION IX. Subsection 4-3-050.E.6 of the RMC is amended as follows:
6. Wetlands: Categorization of wetlands shall be determined in accordance with
subsection G9 of this Section,RMC 4-3-050.G.9 and also refer to the City of Renton
Wetland and Stream Corridors Critical Areas Inventory depicted on the City of Renton’s
ORDINANCE NO. 6179
32
COR Maps, the City’s online interactive mapping application available through the City’s
website.
SECTION X. Section 4-3-050.F of the RMC is amended as follows:
1. Preapplication Consultation: Any person intending to develop properties known or
suspected to have critical areas present is strongly encouraged to meet with the
appropriate City department representative during the earliest possible stages of project
planning before major commitments have been made to a particular land use and/or
project design. Effort put into a preapplication consultation and planning will help
applicants create projects which will be more quickly and easily processed due to a better
understanding on the part of applicants of regulatory requirements.
2. Plans and Studies Required: When an application is submitted for any building
permit or land use review and/or to obtain approval of a use, development or
construction, the location of the critical areas and buffers on the site shall be indicated
on the plans submitted based upon an inventory provided by a qualified
specialistprofessional.
a. Geologically Hazardous Areas:
i. Whenever a proposed development requires a development permit and a
geologic hazard is present on the site of the proposed development or on abutting
or adjacent sites within fifty feet (50') of the subject site, geotechnical studies by
licensed professionals, such as a geotechnical engineer and/or engineering
geologist, shall be required. Specifically, geotechnical studies are required for
ORDINANCE NO. 6179
33
developments proposed on sites with any of the following geologically hazardous
areas:
(a) Sensitive and protected slopes;
(b) Medium, high, or very high landslide hazards;
(c) High erosion hazards;
(d) High seismic hazards;
(e) Medium or high coal mine hazards.
ii. The required studies shall demonstrate the following review criteria can be
met:
(a) The proposal will not increase the threat of the geological hazard to
adjacent or abutting properties beyond pre-development conditions; and
(b) The proposal will not adversely impact other critical areas; and
(c) The development can be safely accommodated on the site.
iii. A mitigation plan may be required consistent with subsection L of this
SectionRMC 4-3-050.L.
iv. Sensitive Slopes – Medium, High and Very High Landslide Hazards – High
Erosion Hazards: Development applications shall submit erosion control plans
consistent with chapter 4-8 RMC, Permits – General and Appeals.
v. Coal Mine Hazards:
(a) Medium Hazard – Report Required: Reports consistent with chapter 4-
8 RMC, Permits – General and Appeals, shall be prepared for development
ORDINANCE NO. 6179
34
proposed within medium coal mine hazard areas and for development
proposed within two hundred feet (200') of a medium coal mine hazard area.
(b) High Hazard – Report Required: Reports consistent with chapter 4-8
RMC, Permits – General and Appeals, shall be prepared for development
proposed within high coal mine hazard areas and for development proposed
within five hundred feet (500') of a high coal mine hazard area.
b. Fish and Wildlife Habitat Conservation Areas: Based upon subsection G6 of this
SectionRMC 4-3-050.G.6, Fish and Wildlife Habitat Conservation Areas, the City shall
require a habitat/wildlife assessment for activities that are located within or abutting
a critical habitat, defined in RMC 4-11-030, or that are adjacent to a critical habitat,
and have the potential to significantly impact a critical habitat. The assessment shall
determine the extent, function and value of the critical habitat and potential for
impacts and mitigation consistent with report requirements in RMC 4-8-120.D.
c. Streams and Lakes: The applicant shall be required to conduct a stream or lake
study pursuant to RMC 4-8-120 if a site contains a water body or buffer area and
changes to buffer requirements or alterations of the water body or its associated
buffer are proposed, either administratively or via a variance request. A stream or lake
study is also required when the project area is within one hundred fifty feet (1050') of
a water body even if the water body is not located on the subject property.
d. Wellhead Protection Areas: The City may require an applicant to prepare a
hydrogeologic study if the proposal has the potential to significantly impact
groundwater quantity or quality, and sufficient information is not readily available.
ORDINANCE NO. 6179
35
Such a report shall be prepared by a qualified professional at the applicant’s expense.
Report content requirements may be specified by the City in accordance with State or
Federal guidelines or tailored to the particular development application. Peer review
of the applicant’s report may be required in accordance with this subsection F.
e. Wetlands:
i. Wetland Categorization: The applicant shall be required to conduct a study
to determine the categorization of the wetland if the subject property or project
area is within two hundred twenty five feet (20025') of a wetland even if the
wetland is not located on the subject property, but it is determined that
alterations of the subject property are likely to impact the wetland in question or
its buffer. If there is a potential Category I or II wetland within three hundred feet
(300') of a proposal, the City may require an applicant to conduct a study even if
the wetland is not located on the subject property, but it is determined that
alterations of the subject property are likely to impact the wetland in question or
its buffer.
ii. Wetland Delineation: A wetland delineation using the methods identified
in the approved federal delineation manual and applicable regional supplement,
as required by WAC 173-22-035, is required for any portion of a wetland or its
buffer on the subject property that will be impacted by the permitted activities.
iii. Wetland Assessment: The applicant shall prepare a wetland assessment
pursuant to RMC 4-8-120.D.23a through j.
ORDINANCE NO. 6179
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f. Period of Validity: Studies submitted and reviewed are valid for five (5) years
from date of study completion unless the Administrator determines that conditions
have changed significantly. The Administrator may extend the period of validity,
provided on-site conditions have not changed.
3. Testing Authorized:
a. Pipeline Requirements – Zone 1, As Identified in Subsection G8 of This Section:
If the Department has reason to believe that the operation or proposed operation of
an existing non-potable water pipeline, defined in RMC 4-11-160, in Zone 1 of a
Wellhead Protection Area, may degrade groundwater quality, the Department may
require leakage testing of the existing pipeline in accordance with subsection G of this
Section; and installation, sampling, and sample analysis of monitoring wells. Routine
leakage testing of existing pipelines in Zone 1 may be required by the Department.
Criteria for this determination are specified in subsection D of this SectionRMC 4-3-
050.D.
Should pipeline leakage testing reveal any leakage at any level, then the
Department shall require immediate repairs to the pipeline to the satisfaction of the
Department such that no infiltration of water into the pipeline or exfiltration of
substances conveyed in the pipeline shall occur. Any repairs which are made shall be
tested for leakage pursuant to subsection G of this SectionRMC 4-3-050.G.
b. Pipeline Requirements – Zone 2, As Identified in Subsection G8 of This
SectionRMC 4-3-050.G.7: If the Department has reason to believe that the operation
or proposed operation of an existing pipeline in Zone 2 of a Wellhead Protection Area
ORDINANCE NO. 6179
37
may degrade groundwater quality, the Department may require leakage testing in
accordance with subsection G of this Section; installation, sampling, and sample
analysis of groundwater monitoring wells; repair of the pipeline to the satisfaction of
the Department such that degradation of groundwater quality is minimized or
eliminated. Criteria for this determination are specified under subsection D of this
SectionRMC 4-3-050.D.
4. Submittal Requirements: In order to be accepted for review, studies shall include
all information as required in chapter 4-8 RMC.
5. Fees: See the currently adopted City of Renton Fee Schedule brochure available at
the City’s website or in the City Clerk’s Office.
6. Independent Secondary Review: The City may require independent review of an
applicant’s report as follows:
a. All Critical Areas: When appropriate due to the type of critical areas, habitat, or
species present, project area conditions, project scope, or potential for negative
impacts to critical areas, or lack of substantial documentation of impact avoidance in
first study, the applicant may be required to prepare and/or fund analyses or
activities, including, but not limited to:
i. An evaluation by an independent qualified professional regarding the
applicant’s analysis and the effectiveness of any proposed mitigating measures or
programs, to include any recommendations as appropriate. This shall be paid at
the applicant’s expense, and the Administrator shall select the third-party review
professional; and/or
ORDINANCE NO. 6179
38
ii. A request for consultation with the Washington Department of Fish and
Wildlife, Washington State Department of Ecology, or the local Native American
Tribe or other appropriate agency; and/or
iii. Detailed surface and subsurface hydrologic features both on and abutting
the site.
b. Additional Requirements for Geologically Hazardous Areas: Independent
secondary review shall be conducted in accordance with the following:
i. Required – Sensitive and Protected Slopes, and Medium, High, or Very High
Landslide Hazards: All geotechnical reports submitted in accordance with this
subsection F, and chapter 4-8 RMC, Permits – General and Appeals, shall be
independently reviewed by qualified specialists selected by the City, at the
applicant’s expense. An applicant may request that independent review be waived
by the Department Administrator in accordance with subsection D of this
SectionRMC 4-3-050.D.
ii. Required for Critical Facilities in High Erosion, High Seismic, Medium Coal
Mine, or High Coal Mine Hazards: The City shall require independent review of a
geotechnical report addressing a critical facility, defined in RMC 4-11-030, by
qualified specialists selected by the City, at the applicant’s expense. An applicant
may request that independent review be waived by the Department
Administrator in accordance with subsection D of this SectionRMC 4-3-050.D.
iii. At City’s Discretion – High Erosion, High Seismic, Medium Coal Mine, or
High Coal Mine Hazards: For any proposal except critical facilities, the City may
ORDINANCE NO. 6179
39
require independent review of an applicant’s geotechnical report by qualified
specialists selected by the City, at the applicant’s expense.
7. Waiver of Submittal Requirements: An applicant may request that the
Administrator waive the report requirement pursuant to subsection D of this SectionRMC
4-3-050.D, where it has been determined through field documentation that critical areas
are not present or as specified below:
a. Habitat Assessment: In cases where a proposal is will not likely to significantly
impact the critical habitat and there is sufficient information to determine the effects
of a proposal, an applicant may request that this report be waived by the
Administrator.
b. Streams and Lakes:
i. Stream or Lake Study: This report may only be waived by the Administrator
when the applicant provides satisfactory evidence that:
(a) A road, building or other barrier exists between the water body and the
proposed activity that results in functional isolation,; or
(b) The water body or required buffer area does not intrude on the
applicant’s lot, and based on evidence submitted, the proposal will not result
in significant adverse impacts to nearby water bodies regulated under this
Section; or
(c) Applicable data and analysis appropriate to the proposed project exists
and an additional study is not necessary.
ORDINANCE NO. 6179
40
ii. Stream or Lake Mitigation Plan: This plan may only be waived when no
impacts have been identified through a stream or lake study.
c. Wetland Assessment: The wetland assessment shall be waived by the
Administrator when the applicant provides satisfactory evidence that a road, building
or other barrier exists between the wetland and the proposed activity, when the
buffer area, determined with a wetland categorization, needed or required will not
intrude on the applicant’s lot, or when applicable data and analysis appropriate to the
project proposed exists and an additional report is not necessary.
SECTION XI. Section 4-3-050.G of the RMC is amended as follows:
1. General: No proposal shall result in a loss of critical area functions or values. If the
application of these provisions would deny all reasonable use of the property, the
applicant may apply for a variance as identified in RMC 4-9-250.
2. Critical Area Buffers and Structure Setbacks from Buffers: The following critical
area buffers and structure setbacks from buffers are established for each critical area.
Table 4-3-050.G.2 Critical Area Buffer Table
Critical Area Category or
Type Critical Area Buffer Width
Structure
Setback
beyond
Buffer1
Flood Hazard Areas
Flood Hazard
Areas None None
Channel
Migration
Zone
None None
Geologically Hazardous Areas
ORDINANCE NO. 6179
41
Critical Area Category or
Type Critical Area Buffer Width
Structure
Setback
beyond
Buffer1
Steep Slopes:2
Sensitive
Slopes None3 None3, 4
Protected
Slopes5 None3 15 ft.1
Landslide Hazards:2
Low None3 None3, 4
Medium None3 None3, 4
High None3 None3, 4
Very High5 50 ft. 15 ft.1
Erosion Hazards:
Low None None
High None None
Seismic Hazards:
Low None None
High None None
Coal Mine Hazards:
Low None3 None3
Medium None3 None3
High None3 None3
Fish and Wildlife Habitat Conservation Areas
Critical
Habitats Established by Administrator per RMC 4-3-050.G 15 ft.1
Streams and Lakes5
Type F 115 ft. 15 ft.1
Type Np 75 ft. 15 ft.1
Type Ns 50 ft. 15 ft.1
Wellhead Protection Areas
Zones 1 and 2 None None
ORDINANCE NO. 6179
42
Critical Area Category or
Type Critical Area Buffer Width
Structure
Setback
beyond
Buffer1
Wetlands6
Low Impact Land Uses:7
High
Habitat
Function
(8-9
points)
Moderate
Habitat
Function
(5-7 points)
Low
Habitat
Function
(3-4
points)
All Other
Scores
15 ft.1
Category I –
Bogs &
Natural
Heritage
Wetlands
175 ft.
Category I –
All Others 175 ft. 125 ft. 75 ft. 75 ft.
Category II 150 ft. 100 ft. 75 ft. n/a
Category III 100 ft. 75 ft. 50 ft. n/a
Category IV 40 ft. n/a
All Other Land Uses:
High
Habitat
Function
(8-9
points)
Moderate
Habitat
Function
(5-7 points)
Low
Habitat
Function
(3-4
points)
All Other
Scores
15 ft.1
Category I –
Bogs &
Natural
Heritage
Wetlands
200 ft.
Category I –
All Others 200 ft. 150 ft. 115 ft. 115 ft.
Category II 175 ft. 150 ft. 100 ft. n/a
Category III 125 ft. 100 ft. 75 ft. n/a
Category IV 50 ft. n/a
ORDINANCE NO. 6179
43
Footnotes:
1. The following may be allowed in the building setback area:
a. Landscaping;
b. Uncovered decks, less than eighteen inches (18") above grade;
c. Building overhangs, if such overhangs do not extend more than
twenty-four inches (24") into the setback area; and
d. Impervious ground surfaces, such as driveways and patios, provided
that such improvements may be subject to water quality regulations and
maximum impervious surface limitations.
e. Other similar architectural elements, as determined by the
Administrator.
2. Buffers shall be established from the top, toe, and sides of slopes.
3. Based upon the results of a geotechnical report and/or independent
review, conditions of approval for developments may include buffers and/or
setbacks from buffers.
4. Unless required pursuant to the adopted building code or Building
Official.
5. When a required stream/lake buffer falls within a protected slope or
very high landslide hazard area, the stream/lake buffer width shall extend to the
boundary of the protected slope of very high landslide hazard area.
6. Areas that are functionally and effectively disconnected from the
wetland by a permanent road or other substantially developed surface of
ORDINANCE NO. 6179
44
sufficient width and with use characteristics such that buffer functions are not
provided shall not be counted toward the minimum buffer unless these areas can
be feasibly removed, relocated or restored to provide buffer functions.
7. Low intensity land uses include but are not limited to the following:
unpaved trails, low intensity open space (hiking, bird-watching, preservation of
natural resources, etc.) and utility corridor without a maintenance road and little
or no vegetation management. Land Use Impacts:
Level of
Impact
Types of Land Use
High Commercial
Urban
Industrial
InsƟtuƟonal
Mixed-use developments
ResidenƟal (more than 1 unit/acre)
Roads: federal and state highways, including on-ramps
and exits, state routes, and other roads associated with
high-impact land uses
Railroads
Agriculture with high-intensity acƟviƟes (dairies,
nurseries, greenhouses, growing and harvesƟng crops
requiring annual Ɵlling, raising and maintaining animals,
etc.)
Open/recreaƟonal space with high-intensity uses (golf
courses, ball fields, etc.)
Solar farms (uƟlity scale)
Moderate
ResidenƟal (1 unit/acre or less)
Roads: Forest Service roads and roads associated with
moderate-impact land uses
Open/recreaƟonal space with moderate-intensity uses
(parks with paved trails or playgrounds, biking, jogging,
etc.)
Agriculture with moderate-intensity uses (orchards, hay
fields, light or rotaƟonal grazing, etc.)
ORDINANCE NO. 6179
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UƟlity corridor or right-of-way used by one or more
uƟliƟes and
including access/maintenance road
Wind farm
Low Natural resource lands (forestry/silviculture–cuƫng of
trees only, not land clearing and removing stumps)
Open/recreaƟonal space with low-intensity uses
(unpaved trails, hiking, birdwatching, etc.)
UƟlity corridor without a maintenance road and liƩle or
no vegetaƟon management
Cell tower
a. Streams and Lakes
Table 4-3-050G.2.a Streams and Lakes Buffer Table
Critical Area Category or Type Critical Area Buffer Width
Structure
Setback
beyond
Buffer1
Streams and Lakes3
Standard Buffer1 Increased
Buffer2
Type F 115 ft 200 ft 15 ft4
Type Np 75 ft 100 ft 15 ft4
Type Ns 50 ft 67 ft 15 ft4
Footnotes:
1. The standard buffer widths apply so long as either the vegetated buffer standards
outlined in RMC 4-3-050.G.2.f are met or the buffer is enhanced to comply with the vegetated
buffer standards through an approved mitigation plan in accordance with RMC 4-3-050.G.2.f.
2. The increased buffer widths apply when either the vegetated buffer standards outlined
in 2.a.i. of this section are not met or the buffer is not enhanced through an approved mitigation
plan in accordance with subsection 2.a.i. of this section.
ORDINANCE NO. 6179
46
3. When a required stream/lake buffer falls within a protected slope or very high landslide
hazard area, the stream/lake buffer width shall extend to the boundary of the protected slope of
very high landslide hazard area.
4. The following may be allowed in the building setback area:
a. Landscaping;
b. Uncovered decks, less than eighteen inches (18") above grade;
c. Building overhangs, if such overhangs do not extend more than
twenty-four inches (24") into the setback area; and
d. Impervious ground surfaces, such as driveways and patios,
provided that such improvements may be subject to water quality
regulations and maximum impervious surface limitations.
e. Other similar architectural elements, as determined by the
Administrator.
b. Classification System: The following classification system is hereby adopted for
the purposes of regulating Streams and Lakes in the City. This classification system is
based on the State’s Permanent Water Typing System WAC 222-16-030. Stream and
lake buffer widths are based on the following rating system:
i. Type S: Waters inventoried as “Shorelines of the State” under RCW 90.58.
These waters are regulated under Renton’s Shoreline Master Program
Regulations, RMC 4-3-090.
ORDINANCE NO. 6179
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ii. Type F: Waters that are known to be used by fish or meet the physical
criteria to be potentially used by fish and that have perennial (year-round) or
seasonal flows.
iii. Type Np: Waters that do not contain fish or fish habitat and that have
perennial (year-round) flows. Perennial stream waters do not go dry any time of a
year of normal rainfall. However, for the purpose of water typing, Type Np waters
include the intermittent dry portions of the perennial channel below the
uppermost point of perennial flow.
iv. Type Ns: Waters that do not contain fish or fish habitat and have
intermittent flows. These are seasonal, non-fish habitat streams in which surface
flow is not present for at least some portion of a year of normal rainfall and are
not located downstream from any stream reach that is a Type Np Water. Ns
Waters must be physically connected by an above-ground channel system to Type
S, F, or Np Waters.
c. Non-regulated: Waters that are considered “intentionally created” not
regulated under this Section include irrigation ditches, grass-lined swales and canals
that do not meet the criteria for Type S, F, Np, or Ns. Purposeful creation must be
demonstrated through documentation, photographs, statements and/or other
persuasive evidence.
d. Measurement:
i. Stream/Lake Boundary: The boundary of a stream or lake shall be
considered to be its ordinary high- water mark (OHWM) as defined in RMC 4-11.
ORDINANCE NO. 6179
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The OHWM shall be flagged in the field by a qualified consultant when any study
is required pursuant to RMC 4-3-050.G.2.
ii. Buffer: The boundary of a buffer shall extend beyond the boundaries of the
stream or lake to the width applicable to the stream/lake class as noted in RMC 4-
3-050.G.2, Critical Area Buffers and Structure Setbacks from Buffers. Where
streams enter or exit pipes, the buffer in this subsection shall be measured
perpendicular to the OHWM from the end of the pipe along the open channel
section of the stream.
Figure 4-3-050.G.2.d.ii. Buffer measurement at pipe opening.
e. Performance Standards: Developments on sites with a stream or associated
critical area buffer shall incorporate the following performance standards in design of
the development as applicable:
ORDINANCE NO. 6179
49
i. Lights shall be directed away from the stream.
ii. Activity that generates noise such as parking lots, generators, and residential
uses shall be located away from the stream, or any noise shall be minimized
through use of design and insulation techniques.
iii. Toxic runoff from new impervious area shall be routed away from the
stream.
iv. Treated water may be allowed to enter the critical area buffer if discharged
as far from the associated critical area as possible and all the City’s adopted
Stormwater Design Manual standards are met. Low Impact Design (LID)
stormwater facilities are considered where feasible.
v. The outer edge of the stream critical area buffer shall be planted with dense
vegetation or install a split rail fence to limit pet or human use.
f. Vegetation Buffer Standards: Standard stream buffer widths required by this
section assume the stream buffer is densely vegetated with a native plant community
appropriate for the ecoregion, consisting of an average of 80% native cover comprised
of trees, shrubs, and groundcover plants. If the existing buffer is unvegetated, sparsely
vegetated, or vegetated with invasive species, the buffer must either be enhanced
through an approved mitigation plan or theincreased buffer per the tableabove will
be applied to ensure the buffer provides adequate functions.
dg. Stream/Lake Buffer Width Requirements:
i. Buffers and Setbacks:
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50
(a) Minimum Stream/Lake Buffer Widths: See subsection G2 of this
SectionRMC 4-3-050.G.2.
(b) Piped or Culverted Streams:
(1) Building structures over a natural stream located in an
underground pipe or culvert except as may be granted by a variance in
RMC 4-9-250 are prohibited. Transportation or utility crossings or other
alterations pursuant to subsection J of this SectionRMC 4-3-050.J are
allowed. Pavement over a pre-existing piped stream is allowed.
Relocation of the piped stream system around structures is allowed. If
structure locations are proposed to be changed or the piped stream is
being relocated around buildings, a hydrologic and hydraulic analysis of
existing piped stream systems will be required for any development
project site that contains a piped stream to ensure it is sized to convey
the one hundred (100) year runoff level from the total upstream tributary
area based on future land use conditions.
(2) No buffers are required along segments of piped or culverted
streams. The City shall require easements and setbacks from pipes or
culverts consistent with stormwater requirements in RMC 4-6-030 and
the adopted drainage manual.
ii. Increased Buffer Width:
(a) Areas of High Blow-down Potential: Where the stream/lake buffer is
in an area of high blow-down potential for trees as identified by a qualified
ORDINANCE NO. 6179
51
professional, the buffer width may be expanded an additional fifty feet (50')
on the windward side.
(b) Habitat Corridors: Where the stream/lake buffer is adjacent to high
functioning critical areas (e.g., wetlands, other streams, other identified
habitats), the stream/lake buffer width shall be extended to the buffer
boundary of the other protected critical area to establish a habitat corridor
as needed to protect or establish contiguous vegetated areas between
streams/lakes and other critical areas.
eh. Criteria for Permit Approval – Type F, Np, and Ns: Permit approval for projects
on or near regulated Type F, Np, and Ns water bodies shall be granted only if the
approval is consistent with the provisions of this subsection, and complies with one
of the following conditions:
i. A proposed action meets the standard provisions of this Section and results
in no net loss of regulated riparian area or shoreline ecological function in the
drainage basin where the site is located; or
ii. A proposed action meets alternative administrative standards pursuant to
this Section and the proposed activity results in no net loss of regulated riparian
area or shoreline ecological function in the drainage basin where the site is
located; or
iii. A variance process is successfully completed and the proposed activity
results in no net loss of regulated riparian area or shoreline ecological function in
the drainage basin where the site is located.
ORDINANCE NO. 6179
52
fi. Incentives for Restoration of Streams Located in an Underground Pipe or
Culvert: Daylighting of culverted watercourses should be encouraged and allowed
with the following modified standards:
i. Residential Zones: Reduced setbacks, lot width and lot depth standards of
chapter 4-2 RMC may be approved without requirement of a variance for lots
that abut the daylighted watercourse to accommodate the same number of lots
as if the watercourse were not daylighted.
ii. Mixed Use, Commercial, and Industrial Zones: Where greater lot coverage
allowances are provided for structured parking in chapter 4-2 RMC, lot coverage
may be increased to the limit allowed for structured parking if instead a stream
is daylighted. The increase in impervious surface allowed shall be equal to the
area of stream restoration.
(a) Standard buffers may be reduced pursuant to subsection I of this
SectionRMC 4-3-050.I. If reduced buffers in subsection I of this SectionRMC
4-3-050.I along with other development standards of the zone would not
allow the same development level as without the watercourse daylighting, a
modification may be requested as in subsection I2c of this SectionRMC 4-3-
050.I.2.c.
(b) When designed consistent with the City’s flood regulations in this
subsection G, portions of the daylighted stream/created buffer may be
considered part of compensatory storage in flood hazard areas.
ORDINANCE NO. 6179
53
(c) Stream relocation is permitted subject to subsection J of this
SectionRMC 4-3-050.J.
j. Wetlands
Table 4-3-050.G.2.j Wetlands Buffer Table
Critical Area Category or Type Critical Area Buffer Width
Structure
Setback
beyond
Buffer3
Wetlands4
Wetland
Characteristic Standard Buffer1 Increased
Buffer2
Category I
Bogs & Natural
Heritage
Wetlands –
Habitat score 8 -
9
225 ft 300 ft
15 ft 3
Natural heritage
wetlands and
bogs – All others
190 ft 250 ft
Habitat score of
8 - 9 225 ft 300 ft
Habitat score of
6 - 7 110 ft 150 ft
Habitat score of
3 - 5 75 ft 100 ft
Category II
Habitat score of
8 - 9 225 ft 300 ft
Habitat score of
6 - 7 110 ft 150 ft
Habitat score of
3 - 5 75 ft 100 ft
Category III
Habitat score of
8 - 9 225 ft 300 ft
Habitat score of
6 - 7 110 ft 150 ft
ORDINANCE NO. 6179
54
Habitat score of
3 - 5 60 ft 80 ft
Category IV All 40 ft 50 ft
Footnotes:
1. To apply the standard buffer width criteria for performance standards under RMC 4-
3-050.G.2.e, vegetation buffer standards under RMC 4-3-050.G.2.n and habitat corridor must be
met.
2. Buffers that do not meet criteria for vegetation buffer standards and habitat corridor
are assigned the increased buffer width.
3. The following may be allowed in the building setback area:
a. Landscaping;
b. Uncovered decks, less than eighteen inches (18") above grade;
c. Building overhangs, if such overhangs do not extend more than
twenty-four inches (24") into the setback area; and
d. Impervious ground surfaces, such as driveways and patios, provided
that such improvements may be subject to water quality regulations and
maximum impervious surface limitations.
e. Other similar architectural elements, as determined by the
Administrator.
4. Areas that are functionally and effectively disconnected from the wetland by a
permanent road or other substantially developed surface of sufficient width and with use
characteristics such that buffer functions are not provided shall not be counted toward the
ORDINANCE NO. 6179
55
minimum buffer unless these areas can be feasibly removed, relocated or restored to provide
buffer functions.
a. Potential or lack of potential to create a protected corridor must be
determined by a qualified professional on a site-specific basis.
b. Presence or absence of the shoreline or priority habitat must be
confirmed by a qualified biologist or shoreline administrator.
c. Performance standards under RMC 4-3-050.G.2.e. are applied.
d. If the area is required to be protected as a habitat corridor by
operation of this subsection is not under common ownership, then the
requirements of this subsection shall only be applied to the portion of the
required habitat corridor required to be located on property that is owned
or controlled by the applicant. The habitat corridor shall then be
completed, at a later date, by a future applicant upon development of the
property not under common ownership.
j. Applicability: Wetland regulations apply to sites containing or abutting
wetlands, defined in RMC 4-11-230, as described below. The City categorizes wetlands
according to the most current version of the Washington State Wetland Rating System
for Western Washington.
k. Delineation of Regulatory Edge of Wetlands:
i. Methodology: For the purpose of regulation, the exact location of the
wetland edge shall be determined by the qualified professional hired at the
ORDINANCE NO. 6179
56
expense of the applicant through the performance of a field investigation in
accordance with the approved federal wetland delineation manual and applicable
regional supplements.
ii. Adjustments to Delineation by City: Where the applicant has provided a
delineation of the wetland edge, the City shall review and may render adjustments
to the edge delineation. In the event the adjusted edge delineation is contested
by the applicant, the City shall, at the applicant’s expense, obtain the services of
an additional qualified professional to review the original study and render a final
delineation.
l. Wetland Categorization or Categorization System: The following categorization
system is hereby adopted for the purposes of regulating wetlands in the City. The City
may accept a dual wetland categorization for a wetland exhibiting a combination of
Category I and II features or a combination of Category I and III features. The City will
not accept a dual rating for a Category II wetland, such as a combined Category II and
III rating. Dual ratings for a Category I wetland shall be consistent with the Washington
State Wetland Rating System for Western Washington – 2014 Update (October 2014)
or as amended hereafter. Wetlands buffer widths, replacement ratios and avoidance
criteria shall be based on Wetland Mitigation in Washington State, Part 1: Agency
Policies and Guidance, Version 2 (Ecology Publication No. 21-06-003, April 2021) and
as may be amended in the future, and the following ratings:
i. Category I Wetlands: Category I wetlands are those wetlands of exceptional
value in terms of protecting water quality, storing flood and stormwater, and/or
ORDINANCE NO. 6179
57
providing habitat for wildlife as indicated the state rating system referenced
above. These are wetland communities of infrequent occurrence that often
provide documented habitat for critical, threatened, or endangered species,
and/or have other attributes that are very difficult or impossible to replace if
altered.
ii. Category II Wetlands: Category II wetlands have significant value based on
their function as indicated by the state rating system referenced above. They do
not meet the criteria for Category I rating but occur infrequently and have qualities
that are difficult to replace if altered.
iii. Category III Wetlands: Category III wetlands have important resource value
as indicated by the state rating system referenced above.
iv. Category IV Wetlands: Category IV wetlands are wetlands of limited
resource value as indicated by the state rating system referenced above. They
typically have vegetation of similar age and class, lack special habitat features,
and/or are isolated or disconnected from other aquatic systems or high quality
upland habitats.
m. Performance Standards
i. Lights shall be directed away from the wetland.
ii. Activity that generates noise such as parking lots, generators, and residential
uses shall be located away from the wetland, or a noise shall be minimized through
use of design and insulation techniques
ORDINANCE NO. 6179
58
iii. Toxic runoff from new impervious area shall be routed away from the
wetlands.
iv. Treated water may be allowed to enter the wetland critical area buffer.
v. The outer edge of the wetland critical area buffer shall be planted with
dense vegetation to limit pet or human use.
n. Vegetation Buffer Standards: All wetland buffer widths presume the buffer is
densely vegetated with a native plant community appropriate for the ecoregion,
consisting of an average of eighty percent (80%) native cover comprised of trees,
shrubs, and groundcover plants. If the existing buffer is unvegetated, sparsely
vegetated, or vegetated with invasive species, the buffer must either be enhanced
through an approved mitigation plan or widened to ensure the buffer provides
adequate functions.
i. Habitat Corridor. Wetlands that score six (6) points or more for habitat
functions the following requirements apply along with standard buffer widths
above.
(a) A relatively undisturbed vegetated corridor at least one hundred feet
(100’) wide between the wetland and the areas listed below when present:
(1) A legally protected, relatively undisturbed and vegetated area (e.g.,
Priority Habitats, compensatory mitigation sites, wildlife areas/refuges,
national, county, and state parks where they have identified areas
designated as Natural, Natural Forest, or Natural Area Preserve; or
ORDINANCE NO. 6179
59
(2) An area that is the site of a Watershed Project identified within,
fully consistent with, a Watershed Plan as defined by RCW 89-08-460; or
(3) An area where development is prohibited according to the
provisions of the local shoreline master program; or
(4) An area with equivalent habitat quality that has conservation status
in perpetuity, in consultation with WDFW.
(b) The corridor is permanently protected for the entire distance between
the wetland and the shoreline or legally protected area by a conservation
easement, deed restriction, or other legal site protection mechanism.
Potential or lack of potential to create a protected corridor must be
determined by a qualified professional on a site-specific basis.
(c) Presence or absence of the shoreline or priority habitat must be
confirmed by a qualified biologist or shoreline administrator.
(d) Performance standards under RMC 4-3-050G.2.m are applied.
(e) If the area is required to be protected as a habitat corridor by operation
of this subsection is not under common ownership, then the requirements of
this subsection shall only be applied to the portion of the required habitat
corridor required to be located on property that is owned or controlled by the
applicant. The habitat corridor shall then be completed, at a later date, by a
future applicant upon development of the property not under common
ownership.
ORDINANCE NO. 6179
60
ii. Wetlands that score five (5) or fewer habitat points, a habitat corridor is not
required.
o. Wetland Buffers:
i. Standard Buffer Widths: See RMC 4-3-050.G.2, Critical Area Buffers and
Structure Setbacks from Buffers.
ii. Independent Buffer Study: The Administrator shall have the authority to
approve proposed alternate buffer widths based on a qualified professional’s
wetland study, provided the criteria below are met.
(a) The applicant funds the wetland study; and
(b) The wetland study shows why the standard buffer widths are
unnecessary and how the proposed alternate buffer will provide an equivalent
ecological protection as provided by the City standards; and
(c) The wetland study demonstrates how it meets best available science as
identified in Wetlands in Washington State, Volume 1: A Synthesis of the
Science (Ecology Publication No. 05-06-006, March 2005) or as amended
hereafter, and Wetlands in Washington State, Volume 2: Managing and
Protecting Wetlands (Ecology Publication No. 04-06-008, April 2005) or as
amended hereafter, Wetland Mitigation in Washington State Part 1: Agency
Policies and Guidance, Version 2 (Ecology Publication No. 21-06-003, April
2021) or as amended hereafter, and Calculating Credits and Debits for
Compensatory Mitigation in Wetlands of Western Washington (Ecology
Publication No. #10-06-011, March 2012) or as amended hereafter.
ORDINANCE NO. 6179
61
iii. Measurement of Buffers: All buffers shall be measured from the wetland
boundary as surveyed in the field pursuant to the requirements of this subsection.
iv. Increased Wetland Buffer Width: Each applicant shall document in the
required wetland assessments whether the criteria in RMC 4-3-050.G.2.o are or
are not met and increased wetland buffers are warranted. Based on the
applicant’s report or third-party review, increased standard buffer widths may be
required in unique cases. Such determination shall be attached as a condition of
project approval. Unique cases shall include but not be limited to:
(a) The wetland is used by species listed by the Federal or the State
government as threatened, endangered and sensitive species and State-listed
priority species, essential habitat for those species or has unusual nesting or
resting sites such as heron rookeries or raptor nesting trees or evidence
thereof; or
(b) The buffer or adjacent uplands have a slope greater than fifteen
percent (15%) or is susceptible to erosion and standard erosion control
measures will not effectively prevent adverse wetland impacts; or.
(c) When a larger buffer is necessary to protect wetlands functions and
values.
p. Cooperative Wetland Compensation: Mitigation Banks, In-Lieu Fee Programs,
or Special Area Management Programs (SAMP):
i. Applicability: The City encourages and will facilitate and approve
cooperative projects wherein a single applicant or other organization with
ORDINANCE NO. 6179
62
demonstrated capability may undertake a compensation project under the
following circumstances:
(a) Restoration or creation on site may not be feasible due to problems
with hydrology, soils, or other factors; or
(b) Where the cooperative plan is shown to better meet established
regional goals for flood storage, flood conveyance, habitat or other wetland
functions.
ii. Process: Applicants proposing a cooperative compensation project shall:
(a) Submit a permit application;
(b) Demonstrate compliance with all standards;
(c) Demonstrate that long-term management will be provided; and
(d) Demonstrate agreement for the project from all affected property
owners of record.
iii. Mitigation Banks: Mitigation banks are defined as sites which may be used
for restoration, creation and/or mitigation of wetland alternatives from a different
piece of property than the property to be altered within the same drainage basin.
If credits are from a mitigation bank are to be used for Federal or State permits,
the bank must be certified under State rules. If approved, compensation payments
received as part of a mitigation or creation bank must be received prior to the
issuance of an occupancy permit.
iv. In-Lieu Fee Programs: In-lieu fee mitigation involves the restoration,
creation, enhancement, or preservation of aquatic resources through funds paid
ORDINANCE NO. 6179
63
to a governmental or non-profit natural resources management entity to satisfy
compensatory mitigation for Federal, State, and local permits. Both the U.S. Army
Corps of Engineers (33 CFR §§ 325, 332) and Washington State (WAC 173-700)
allow the use of in-lieu fee programs. The City of Renton is located within the
service area of the King County Mitigation Reserves In-Lieu Fee Program, which
may be used by applicants with the approval of the Administrator and Public
Works Department provided the mitigation occurs within the City of Renton and
the same drainage basin.
v. Special Area Management Programs: Special area management programs
are those wetland programs agreed upon through an interjurisdictional planning
process involving the U.S. Army Corps of Engineers, the Washington State
Department of Ecology, any affected counties and/or cities, private property
owners and other parties of interest. The outcome of the process is a regional
wetlands permit representing a plan of action for all wetlands within the special
area.
3. Native Growth Protection Areas:
a. Required: A native growth protection area shall be instituted to protect a critical
area from any proposed development for a non-exempt activity as follows:
i. Protected slopes and their associated buffers.
ii. Very high landslide hazard areas and their associated buffers.
iii. Class F, Np, and Ns, as defined in subsection G7 of this SectionRMC 4-3-
050.G.2.a, streams or lakes and their associated buffers.
ORDINANCE NO. 6179
64
iv. Category I, II, III, or IV wetlands, as defined in subsection G9c of this
SectionRMC 4-3-050.G.2.l, and their associated buffers.
b. May Be Required: Native growth protection areas may be required for high
landslide hazard area buffers, or for critical fish and wildlife habitats areas and their
buffers.
4. Flood Hazard Areas:
a. Classification: Flood hazard areas are defined as the land in the floodplain
subject to one percent (1%) or greater chance of flooding in any given year.
Designation on flood maps always includes the letters A or V.
b. Data to Be Used for Existing and Future Flow Conditions: The City shall
determine the components of the flood hazard areas after obtaining, reviewing and
utilizing base flood elevations and available floodplain data for a flood having a one
percent (1%) chance of being equaled or exceeded in any given year, often referred
to as the “one hundred (100) year flood.” The City may require projections of future
flow conditions for proposals in unmapped potential flood hazard areas.
c. General Standards: In all flood hazard areas, the following standards are
required:
i. Anchoring – All New Construction: All new construction and substantial
improvements shall be anchored to prevent flotation, collapse, or lateral
movement of the structure resulting from hydrodynamic and hydrostatic loads
including the effects of buoyancy.
ORDINANCE NO. 6179
65
ii. Anchoring – Manufactured Homes: All manufactured homes must likewise
be anchored to prevent flotation, collapse or lateral movement, and shall be
installed using methods and practices that minimize flood damage. Anchoring
methods may include, but are not limited to, use of over-the-top or frame ties to
ground anchors (reference FEMA’s Manufactured Home Installation in Frequently
Flooded Areas guidebook for additional techniques).
iii. Construction Materials and Methods:
(a) All new construction and substantial improvements shall be
constructed with materials and utility equipment resistant to flood damage.
(b) All new construction and substantial improvements shall be
constructed using methods, statutes, codes, rules, regulations and practices
that minimize flood damage.
(c) Electrical, heating, ventilation, plumbing, and air-conditioning
equipment and other service facilities shall be designed and/or otherwise
elevated or located so as to prevent water from entering or accumulating
within the components during conditions of flooding.
iv. Utilities:
(a) All new and replacement water supply systems shall be designed to
minimize or eliminate infiltration of flood waters into the system. A proposed
water well shall be located on high ground that is not in the floodway (WAC
173-160-171).
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(b) New and replacement sanitary sewage systems shall be designed to
minimize or eliminate infiltration of flood waters into the systems and
discharge from the systems into flood waters.
(c) On-site waste disposal systems shall be located to avoid impairment to
them or contamination from them during flooding.
v. Subdivision Proposals:
(a) All subdivision proposals shall be consistent with the need to minimize
flood damage;
(b) All subdivision proposals shall have public utilities and facilities such as
sewer, gas, electrical, and water systems located and constructed to minimize
flood damage;
(c) All subdivision proposals shall have adequate drainage provided to
reduce exposure to flood damage; and
(d) All subdivision proposals shall show the flood hazard areas information
and boundary on the subdivision drawing including the nature, location,
dimensions, and elevations of the subdivided area.
vi. Project Review:
(a) A development permit shall be obtained before construction or
development begins within any area of special flood hazard established in
subsection D3c of this SectionRMC 4-3-050.D.3.c. The permit shall be for all
structures including manufactured homes, as set forth in chapter 4-11 RMC,
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Definitions, and for all development including fill and other activities, also as
set forth in the chapter 4-11 RMC, Definitions.
(b) Where elevation data is not available, either through the flood
insurance study (FIS), Flood Insurance Rate Map (FIRM), or from another
authoritative source (subsection D3f of this SectionRMC 4-3-050.D.3.f),
applications for floodplain development shall be reviewed to assure that
proposed construction will be reasonably safe from flooding. The test of
reasonableness is a local judgment and includes use of historical data, high
water marks, photographs of past flooding, etc., where available. Failure to
elevate at least two feet (2') above the highest adjacent grade in these zones
may result in higher insurance rates.
(c) Where base flood elevation data has not been provided or is not
available from another authoritative source, it shall be generated by the
applicant.
(d) Review all development permits to determine that:
(1) The permit requirements of this Section have been satisfied;
(2) All other required state and federal permits have been obtained;
(3) The site is reasonably safe from flooding;
(4) The proposed development is not located in the floodway. If located
in the floodway, asensure the encroachment provisions of subsectionRMC
4.3.050.G.4.e.i of this Section are met.
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(5) The proposed development is not located in a channel migration
zone. If located in a channel migration zone, ensure the additional
provisions of subsection G.4.f of this Section are met; and
(5)(6) Notify FEMA when annexations occur in the Special Flood Hazard
Area.
d. Specific Standards: In all flood hazard areas, the following provisions are
required:
i. Residential Construction:
(a) In AE and A1-30 zones or other A zoned areas where the base flood
elevation has been determined or can be reasonably obtained, new
construction and substantial improvement of any residential structure shall
have the lowest floor, which for the purposes of this Section includes
basement or attached garage as described in subsection G4di(e)(4) of this
SectionRMC 4-3-050.G.4.d.i.e.4, elevated one foot (1') or more above the base
flood elevation. Mechanical equipment, ductwork, and utilities shall be
elevated at least one foot (1') above the base flood elevation.
(b) New construction and substantial improvement of any residential
structure in an AO zone shall meet the requirements in Appendix A, attached
to Ordinance 5977, or superseding ordinances.
(c) New construction and substantial improvement of any residential
structure in an Unnumbered A zone, for which a base flood elevation is not
available and cannot be reasonably obtained, shall be reasonably safe from
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flooding, but in all cases the lowest floor and any attached garage floor shall
be at least two feet (2') above the highest adjacent grade.
(d) If buildings or manufactured homes are constructed or substantially
improved with fully enclosed areas below the lowest floor, the areas shall be
used solely for parking of vehicles, building access, or storage.
(e) Fully enclosed areas below the lowest floor that are subject to flooding
are prohibited, or shall be designed to automatically equalize hydrostatic flood
forces on exterior walls by allowing for the entry and exit of floodwaters.
Designs for meeting this requirement must meet or exceed the following
minimum criteria:
(1) Have a minimum of two (2) openings with a total net area of not
less than one (1) square inch for every square foot of enclosed area subject
to flooding; and
(2) The bottom of all openings shall be no higher than one foot (1')
above grade; and
(3) Openings may be equipped with screens, louvers, valves, or other
coverings or devices provided that they permit the automatic entry and
exit of floodwater; and
(4) A garage attached to a residential structure, constructed with the
garage floor slab below the base flood elevation, must be designed to
allow for the automatic entry and exit of floodwaters.
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Alternatively, a registered engineer or architect may design and certify
engineered openings.
ii. Manufactured Homes:
(a) All manufactured homes to be placed or substantially improved within
Zones A1-A30, AH, and AE on the community’s Flood Insurance Rate Map
(FIRM), shall be elevated on a permanent foundation such that the lowest floor
of the manufactured home is elevated a minimum of one foot (1') above the
base flood elevation and be secured to an adequately anchored foundation
system to resist flotation, collapse and lateral movement. Mechanical
equipment, ductwork, and utilities shall be elevated at least one foot (1')
above the base flood elevation.
(b) Manufactured homes to be placed or substantially improved on sites in
an existing manufactured home park or subdivision within Zones A1-30, AH,
and AE on the community’s FIRM that are not subject to the above
manufactured home provisions shall be elevated so that the lowest floor of
the manufactured home is elevated a minimum of one foot (1') above the base
flood elevation and be secured to an adequately anchored foundation system
to resist flotation, collapse, and lateral movement. Mechanical equipment,
ductwork, and utilities shall be elevated at least one foot (1') above the base
flood elevation.
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(c) If buildings or manufactured homes are constructed or substantially
improved with fully enclosed areas below the lowest floor, the areas shall be
used solely for parking of vehicles, building access, or storage.
iii. Nonresidential Construction: New construction or substantial
improvement of any commercial, industrial or other nonresidential structure shall
meet the requirements of subsection G.4.d.iii(a) or G4diii(b) of this SectionRMC 4-
3-050.G.d.iii.a or 4-3-050.G.d.iii.b:
(a) New construction or substantial improvement of any commercial,
industrial or other nonresidential structure shall meet all of the following
requirements:
(1) In AE and A1-30 zones or other A zoned areas where the base flood
elevation has been determined or can be reasonably obtained, new
construction and substantial improvement of any commercial, industrial,
or other nonresidential structure shall have the lowest floor, including
basement, elevated one foot (1') or more above the base flood elevation,
or elevated as required by ASCE 24, whichever is greater. Mechanical
equipment and utilities shall be elevated at least one foot (1') above the
base flood elevation, or as required by ASCE 24, whichever is greater.
(2) If located in an AO zone, the structure shall meet the requirements
in Appendix A, attached to Ordinance 5977, or superseding ordinances.
(3) If located in an Unnumbered A zone for which a BFE is not available
and cannot be reasonably obtained, the structure shall be reasonably safe
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from flooding, but in all cases the lowest floor shall be at least two feet (2')
above the highest adjacent grade.
(4) If buildings or manufactured homes are constructed or substantially
improved with fully enclosed areas below the lowest floor, the areas shall
be used solely for parking of vehicles, building access, or storage.
(5) Fully enclosed areas below the lowest floor that are subject to
flooding are prohibited, or shall be designed to automatically equalize
hydrostatic flood forces on exterior walls by allowing for the entry and exit
of floodwaters. Designs for meeting this requirement must either be
certified by a registered professional engineer or architect or must meet
or exceed the following minimum criteria:
(A) Have a minimum of two (2) openings with a total net area of
not less than one (1) square inch for every square foot of enclosed area
subject to flooding; and
(B) The bottom of all openings shall be no higher than one foot (1')
above grade; and
(C) Openings may be equipped with screens, louvers, valves, or
other coverings or devices provided that they permit the automatic
entry and exit of floodwater; and
(D) A garage attached to a residential structure, constructed with
the garage floor slab below the BFE, must be designed to allow for the
automatic entry and exit of floodwaters.
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Alternatively, a registered engineer or architect may design and certify
engineered openings.
(b) If the requirements of subsection G.4.d.iii(a) of this SectionRMC 4-3-
050.G.4.d.iii.a are not met, then new construction and substantial
improvement of any commercial, industrial or other nonresidential structure
shall meet all of the following requirements:
(1) Be dry flood proofed so that below one foot (1') or more above the
base flood level the structure is watertight with walls substantially
impermeable to the passage of water or dry flood proofed to the elevation
required by ASCE 24, whichever is greater; and
(2) Have structural components capable of resisting hydrostatic and
hydrodynamic loads and effects of buoyancy; and
(3) Be certified by a registered professional engineer or architect that
the design and methods of construction are in accordance with accepted
standards of practice for meeting provisions of this subsection based on
their development and/or review of the structural design, specifications
and plans. Such certifications shall be provided to the official as set forth
in subsection D3a of this SectionRMC 4-3-050.D.3.a; and
(4) Nonresidential structures that are elevated, not flood proofed,
must meet the same standards for space below the lowest floor as
described in subsection G4diii(a)(5) of this SectionRMC 4-3-
050.G.4.d.iii.a.5.; and
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(c) Applicants who are flood proofing nonresidential buildings shall be
notified that flood insurance premiums will be based on rates that are one foot
(1') below the flood proofed level (e.g. a building flood proofed to the base
flood level will be rated as one foot (1') below).
iv. Recreational Vehicles: Recreational vehicles placed on sites within Zones
A1-30, AH, and AE on the community’s FIRM, not including recreational vehicle
storage lots, shall either:
(a) Be on the site for fewer than one hundred eighty (180) consecutive
days;
(b) Be fully licensed and ready for highway use, on its wheels or jacking
system, attached to the site only by quick disconnect type utilities and security
devices, and have no permanently attached additions; or
(c) Meet the requirements of this subsection G and the elevation and
anchoring requirements for manufactured homes.
e. Additional Restrictions within Floodways: Floodways, defined in RMC 4-11-
060, are located within flood hazard areas established in subsection D of this
SectionRMC 4-3-050.D. Since the floodway is an extremely hazardous area due to the
velocity of flood waters which carry debris, potential projectiles, and erosion
potential, the following provisions apply:
i. Increase in Flood Levels Prohibited: Encroachments, including fill, new
construction, substantial improvements, and other development are prohibited
unless certification by a registered professional engineer demonstrates through
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hydrologic and hydraulic analyses performed in accordance with standard
engineering practice that:
(a) Encroachments shall not result in any increase in flood levels during the
occurrence of the base flood discharge; and
(b) There are no adverse impacts to the subject property or abutting or
adjacent properties; and
(c) There are no higher flood elevations upstream; and
(d) The impact due to floodway encroachment shall be analyzed using
future land use condition flows.
ii. Residential Construction in Floodways: Construction or reconstruction of
residential structures is prohibited within designated floodways, except for:
(a) Repairs, reconstruction, or improvements to a structure which do not
increase the ground floor area; and
(b) Repairs, reconstruction or improvements to a structure, the cost of
which does not exceed fifty percent (50%) of the market value of the structure
either: (1) before the repair, reconstruction, or improvement is started; or (2)
if the structure has been damaged, and is being restored, before the damage
occurred. Work done on structures to comply with existing health, sanitary, or
safety codes or to structures identified as historic places may be excluded in
the fifty percent (50%).
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iii. Compliance Requirements: If this subsection G is satisfied, all new
construction and substantial improvements shall comply with all applicable flood
hazard areas reduction provisions of this Section.
iv. Bridges Crossing Floodways: In mapped or unmapped flood hazard areas,
future flow conditions shall be considered for proposed bridge proposals crossing
floodways.
v. Additional Provisions within AO Zones: Shallow flooding areas appear on
FIRMs as AO zones with depth designations. The base flood depths in these zones
range from one to three feet (1' to 3') above ground where a clearly defined
channel does not exist, or where the path of flooding is unpredictable and where
velocity flow may be evident. Such flooding is usually characterized as sheet flow.
In addition to other provisions in this code, the following additional provisions also
apply in AO zones:
(a) New construction and substantial improvements of residential
structures and manufactured homes within AO zones shall have the lowest
floor (including basement and mechanical equipment) elevated above the
highest adjacent grade to the structure, one foot (1') or more above the depth
number specified in feet on the community’s FIRM (at least two feet (2') above
the highest adjacent grade to the structure if no depth number is specified).
(b) New construction and substantial improvements of nonresidential
structures within AO zones shall either:
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(1) Have the lowest floor elevated above the highest adjacent grade of
the building site, one foot (1') or more above the depth number specified
on the FIRM (at least two feet (2') if no depth number is specified); or
(2) Together with attendant utility and sanitary facilities, be above that
level described in G.4.b.v(b)(1) of this SectionRMC 4-3-050.G.4.e.v.b.1 so
that any space below that level is watertight with walls substantially
impermeable to the passage of water and with structural components
having the capability of resisting hydrostatic and hydrodynamic loads and
effects of buoyancy. If this method is used, compliance shall be certified by
a registered professional engineer, or architect as described in subsection
G4diii(b)(3) of this SectionRMC 4-3-050.G.4.d.iii.b.3.
(c) Require adequate drainage paths around structures on slopes to guide
floodwaters around and away from proposed structures.
(d) Recreational vehicles placed on sites within AO zones on the
community’s FIRM either:
(1) Be on the site for fewer than one hundred eighty (180) consecutive
days; or
(2) Be fully licensed and ready for highway use, on its wheels or jacking
system, is attached to the site only by quick disconnect type utilities and
security devices, and has no permanently attached additions; or
(3) Meet the requirements of subsections G4ev(a) and (b) of this
SectionRMC 4-3-050.G.4.e.v.a and 4-3-050.G.4.e.v.b and the anchoring
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requirements for manufactured homes (subsection G4dii of this
SectionRMC 4-3-050.G.4.d.ii).
vi. AE and A1-30 Zones with Base Flood Elevations but No Floodways: In areas
with BFEs (when a regulatory floodway has not been designated), no new
construction, substantial improvements, or other development (including fill)
shall be permitted within Zones A1-30 and AE on the community’s FIRM, unless it
is demonstrated that the cumulative effect of the proposed development, when
combined with all other existing and anticipated development, will not increase
the water surface elevation of the base flood more than one foot (1') at any point
within the community.
f. Additional Restrictions within Channel Migration Zone: Channel migration
zones, defined in RMC 4-11-030 and established in RMC 4-3-050.D, identify hazardous
areas with significant erosion potential; therefore, the following provisions apply to
land within channel migration zones:
i. Residential Construction within Channel Migration Zone: New residential
development shall not require new shoreline stabilization. Developable portions
of lots shall not be subject to flooding or require structural flood hazard reduction
measures within a channel migration zone to support intended development
during the life of the development or use. Prior to approval, analysis of the site
and shoreline characteristics shall demonstrate that new shoreline stabilization is
unlikely to be necessary for each new lot to support intended development during
the life of the development or use.
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ii. All Development: All new construction and substantial improvements shall
be constructed using methods and practices that reduce the risk of damage due
to erosion caused by channel migration.
iii. Bridges: Construction of a new bridge shall be permissible if there is no
feasible alternative with less impact on the critical area, the bridge is located to
minimize encroachment into the channel migration zone, and bridge piers or
abutments for bridge crossings are not placed within the severe channel migration
zone.
iv. Mapping Discrepancy: An applicant for a development proposal may
submit a report to the department to determine channel migration zone
boundaries or classify channel migration hazard areas on a specific property if
there is an apparent discrepancy between the site-specific conditions or data and
the adopted channel migration zone mapping. The geomorphic assessment shall
be prepared by a geologist licensed in Washington State with an engineering
geology or hydrogeology specialty license and experience conducting fluvial
geomorphic assessments. If the Administrator determines there is a discrepancy
between the site conditions and the adopted channel migration zone maps, the
City shall make appropriate revisions to the mapped channel migration zone.
fg. Critical Facility: Construction of new critical facilities, as defined in RMC 4-11-
030, shall be, to the extent possible, located outside the limits of flood hazard areas
(one hundred (100) year) floodplain and channel migration zone. Construction of new
critical facilities shall be permissible within flood hazard areas or and channel
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migration zones if no feasible alternative site is available. Critical facilities constructed
within flood hazard areas shall have the lowest floor elevated three feet (3') or more
above the level of the base flood elevation (one hundred (100) year) at the site.
Floodproofing and sealing measures must be taken to ensure that toxic substances
will not be displaced by or released into flood waters. Access routes elevated to or
above the level of the base flood elevation shall be provided to all critical facilities to
the extent possible.
gh. Compensatory Storage:
i. Compensatory Storage Required: Development proposals and other
alterations shall not reduce the effective base flood storage volume of the
floodplain. If grading or other activity will reduce the effective storage volume,
compensatory storage shall be created on the site or off the site if legal
arrangements can be made to assure that the effective compensatory storage
volume will be preserved over time. Compensatory storage shall be configured so
as not to trap or strand salmonids after flood waters recede and may be
configured to provide salmonid habitat or high flow refuge whenever suitable site
conditions exist and the configuration does not adversely affect bank stability or
existing habitat. Effective base flood storage volume shall be based on the
elevations shown in the flood hazard areas map, identified in subsection E3 of this
SectionRMC 4-3-050.E.3 or as determined through a study where no base flood
evaluation information exists.
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ii. Determining Finished Floor Elevations According to FEMA: The FEMA one
hundred (100) year flood plain elevations shall be used to establish building
finished floor elevations to comply with other National Flood Insurance Program
requirements.
5. Geologically Hazardous Areas Defined:
a. Steep Slope Types:
i. Sensitive Slopes: A hillside, or portion thereof, characterized by: (a) an
average slope of twenty five percent (25%) to less than forty percent (40%) as
identified in the City of Renton Steep Slope Atlas or in a method approved by the
City; or (b) an average slope of forty percent (40%) or greater with a vertical rise
of less than fifteen feet (15') as identified in the City of Renton Steep Slope Atlas
or in a method approved by the City; (c) abutting an average slope of twenty five
percent (25%) to forty percent (40%) as identified in the City of Renton Steep Slope
Atlas or in a method approved by the City. This definition excludes engineered
retaining walls.
ii. Protected Slopes: A hillside, or portion thereof, characterized by an average
slope of forty percent (40%) or greater grade and having a minimum vertical rise
of fifteen feet (15') as identified in the City of Renton Steep Slope Atlas or in a
method approved by the City.
b. Landslide Hazards:
i. Low Landslide Hazard (LL): Areas with slopes less than fifteen percent (15%).
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ii. Medium Landslide Hazard (LM): Areas with slopes between fifteen percent
(15%) and forty percent (40%) and underlain by glacially consolidated soils that
consist largely of sand, gravel or glacial till.
iii. High Landslide Hazards (LH): Areas with slopes greater than forty percent
(40%), and areas with slopes between fifteen percent (15%) and forty percent
(40%) and underlain by soils consisting largely of silt and clay non-glacially
consolidated soils, and areas with slopes between fifteen percent (15%) and forty
percent (40%) with adverse groundwater conditions to include slopes that
intersect geologic contacts with a relatively permeable sediment overlying a
relatively impermeable sediment or bedrock and/or where seeps or springs or
indicators (e.g., vegetation type) of a shallow groundwater table are observed on
or adjacent to the face of the slope.
iv. Very High Landslide Hazards (LV): Areas of known mapped or identified
landslide deposits.
c. Erosion Hazards:
i. Low Erosion Hazard (EL): Areas with soils characterized by the Natural
Resource Conservation Service (formerly U.S. Soil Conservation Service) as having
slight or moderate erosion potential, and a slope less than fifteen percent (15%).
ii. High Erosion Hazard (EH): Areas with soils characterized by the Natural
Resource Conservation Service (formerly U.S. Soil Conservation Service) as having
severe or very severe erosion potential, and a slope more than fifteen percent
(15%).
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d. Seismic Soil Liquefaction Hazards:
i. Low Seismic Hazard (SL): Areas underlain by glacially consolidated or
otherwise dense soils or bedrock. These soils generally have site classifications of
A through D, as defined in the International Building Code, 2012.
ii. High Seismic Hazard (SH): Areas underlain by soft or loose, saturated soils,
such as alluvium or artificial fill overlaying alluvium. These soils generally have site
classifications E or F, as defined in the International Building Code, 2012.
e. Coal Mine Hazards:
i. Low Coal Mine Hazards (CL): Areas with no known mine workings and no
predicted subsidence. While no mines are known in these areas, undocumented
mining is known to have occurred.
ii. Medium Coal Mine Hazards (CM): Areas where mine workings are deeper
than two hundred feet (200') for steeply dipping seams, or deeper than fifteen
(15) times the thickness of the seam or workings for gently dipping seams. These
areas may be affected by subsidence.
iii. High Coal Mine Hazard (CH): Areas with abandoned and improperly sealed
mine openings and areas underlain by mine workings shallower than two hundred
feet (200') in depth for steeply dipping seams, or shallower than fifteen (15) times
the thickness of the seam or workings for gently dipping seams. These areas may
be affected by collapse or other subsidence.
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f. Protected Slopes, as defined in subsection G5aii of this SectionRMC 4-3-
050.G.5.a.ii: Development is prohibited on protected slopes. Exceptions to this
prohibition may be granted pursuant to subsection J of this SectionRMC 4-3-050.J.
g. Sensitive Slopes – Medium, High and Very High Landslide Hazards – High
Erosion Hazards: During construction, weekly on-site inspections under the direction
of a licensed geotechnical professional shall be required at the applicant’s expense.
The licensed geotechnical professional directing inspections shall be the same as the
professional that prepared the required geotechnical study for the geologically
hazardous area or shall provide documentation indicating they concur and accept the
conclusions and recommendations in the geotechnical study. Weekly reports
prepared by or under the direction of a Certified Erosion & Sediment Control Lead
(CESCL) documenting erosion control measures shall be required for High Erosion
Hazards.
h. Very High Landslide Hazards:
i. Prohibited Development: Development shall not be permitted on land
designated with very high landslide hazards. Exceptions to this prohibition may be
granted pursuant to subsection J of this SectionRMC 4-3-050.J.
ii. Buffer Modification: The Administrator may increase or decrease the
required buffer based upon the results of a geotechnical report, and any increase
or decrease based upon the results of the geotechnical report shall be
documented in writing and included with the project approval. The modified
standard shall be based on consideration of the best available science as described
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in WAC 365-195-905; or where there is an absence of valid scientific information,
the steps in RMC 4-9-250 shall be followed.
i. Coal Mine Hazards:
i. Mitigation – Additional Engineering Design and Remediation
Specifications: After approval of the mitigation approach proposed as a result of
RMC 4-3-050.D, and prior to construction, the applicant shall complete
engineering design drawings and specifications for remediation. Upon approval of
the plans and specifications, the applicant shall complete the remediation. Hazard
mitigation shall be performed by or under the direction of a licensed geotechnical
engineer or engineering geologist. The applicant shall document the hazard
mitigation by submitting as-builts and a remediation construction report.
ii. Hazards Found during Construction: Any hazards found during any
development activities shall be immediately reported to the Development
Services Division. Any coal mine hazards shall be mitigated prior to recommencing
construction based upon supplemental recommendations or reports by the
applicant’s geotechnical professional.
iii. Construction in Areas with Combustion: Construction shall not be
permitted where surface or subsurface investigations indicate the possible
presence of combustion in the underlying seam or seams, unless the impact is
adequately mitigated in accordance with the recommendations of the applicant’s
geotechnical professional.
6. Fish and Wildlife Habitat Conservation Areas:
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a. Classification of Critical Habitats: Habitats that have a primary association with
the documented presence of non-salmonid or salmonid species proposed or listed by
the Federal government or State of Washington as endangered, threatened, sensitive
and/or of local importance.
b. Mapping: Critical habitats are identified by lists, categories and definitions of
species promulgated by the Washington State Department of Fish and Wildlife (Non-
game Data System Special Animal Species) as identified in WAC 220-200-100; in the
Priority Habitat and Species Program of the Washington State Department of Fish and
Wildlife; or by rules and regulations adopted currently or hereafter by the U.S. Fish
and Wildlife Service.
c. Buffers: The Administrator shall require the establishment of buffer areas for
activities in, or adjacent to, habitat conservation areas when needed to protect fish
and wildlife habitats of importance. Buffers shall consist of an undisturbed area of
native vegetation, or areas identified for restoration, established to protect the
integrity, functions and values of the affected habitat. Buffer widths shall be based
on:
i. Type and intensity of human activity proposed to be conducted on the site
and adjacent sites.
ii. Recommendations contained within a habitat assessment report.
iii. Management recommendations issued by the Washington Department of
Fish and Wildlife.
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d. Alterations Require Mitigation: The Administrator may approve mitigation to
compensate for adverse impacts of a development proposal to habitat conservation
areas through use of a federally and/or state certified mitigation bank or in-lieu fee
program. See subsection L of this SectionRMC 4-3-050.L.
7. Streams and Lakes:
a. Classification System: The following classification system is hereby adopted for
the purposes of regulating Streams and Lakes in the City. This classification system is
based on the State’s Permanent Water Typing System WAC 222-16-030. Stream and
lake buffer widths are based on the following rating system:
i. Type S: Waters inventoried as “Shorelines of the State” under chapter 90.58
RCW. These waters are regulated under Renton’s Shoreline Master Program
Regulations, RMC 4-3-090.
ii. Type F: Waters that are known to be used by fish or meet the physical
criteria to be potentially used by fish and that have perennial (year-round) or
seasonal flows.
iii. Type Np: Waters that do not contain fish or fish habitat and that have
perennial (year-round) flows. Perennial stream waters do not go dry any time of a
year of normal rainfall. However, for the purpose of water typing, Type Np waters
include the intermittent dry portions of the perennial channel below the
uppermost point of perennial flow.
iv. Type Ns: Waters that do not contain fish or fish habitat and have
intermittent flows. These are seasonal, non-fish habitat streams in which surface
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flow is not present for at least some portion of a year of normal rainfall and are
not located downstream from any stream reach that is a Type Np Water. Ns
Waters must be physically connected by an above-ground channel system to Type
S, F, or Np Waters.
b. Non-regulated: Waters that are considered “intentionally created” not
regulated under this Section include irrigation ditches, grass-lined swales and canals
that do not meet the criteria for Type S, F, Np, or Ns Non-regulated waters may also
include streams created as mitigation. Purposeful creation must be demonstrated
through documentation, photographs, statements and/or other persuasive evidence.
c. Measurement:
i. Stream/Lake Boundary: The boundary of a stream or lake shall be
considered to be its ordinary high- water mark (OHWM) as defined in RMC 4-11.
The OHWM shall be flagged in the field by a qualified consultant when any study
is required pursuant to this subsection G7.
ii. Buffer: The boundary of a buffer shall extend beyond the boundaries of the
stream or lake to the width applicable to the stream/lake class as noted in
subsection G2 of this Section, Critical Area Buffers and Structure Setbacks from
Buffers. Where streams enter or exit pipes, the buffer in this subsection shall be
measured perpendicular to the OHWM from the end of the pipe along the open
channel section of the stream.
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Figure 4-3-050.G.7.c.ii. Buffer measurement at pipe opening.
d. Stream/Lake Buffer Width Requirements:
i. Buffers and Setbacks:
(a) Minimum Stream/Lake Buffer Widths: See subsection G2 of this
Section.
(b) Piped or Culverted Streams:
(1) Building structures over a natural stream located in an underground
pipe or culvert except as may be granted by a variance in RMC 4-9-250 are
prohibited. Transportation or utility crossings or other alterations pursuant
to subsection J of this Section are allowed. Pavement over a pre-existing
piped stream is allowed. Relocation of the piped stream system around
structures is allowed. If structure locations are proposed to be changed or
the piped stream is being relocated around buildings, a hydrologic and
hydraulic analysis of existing piped stream systems will be required for any
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development project site that contains a piped stream to ensure it is sized
to convey the one hundred (100) year runoff level from the total upstream
tributary area based on future land use conditions.
(2) No buffers are required along segments of piped or culverted
streams. The City shall require easements and setbacks from pipes or
culverts consistent with stormwater requirements in RMC 4-6-030 and the
adopted drainage manual.
ii. Increased Buffer Width:
(a) Areas of High Blow-down Potential: Where the stream/lake buffer is
in an area of high blow-down potential for trees as identified by a qualified
professional, the buffer width may be expanded an additional fifty feet (50')
on the windward side.
(b) Habitat Corridors: Where the stream/lake buffer is adjacent to high
functioning critical areas (e.g., wetlands, other streams, other identified
habitats), the stream/lake buffer width shall be extended to the buffer
boundary of the other protected critical area to establish a habitat corridor as
needed to protect or establish contiguous vegetated areas between
streams/lakes and other critical areas.
e. Criteria for Permit Approval – Type F, Np, and Ns: Permit approval for projects
on or near regulated Type F, Np and Ns water bodies shall be granted only if the
approval is consistent with the provisions of this subsection, and complies with one
of the following conditions:
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i. A proposed action meets the standard provisions of this Section and results
in no net loss of regulated riparian area or shoreline ecological function in the
drainage basin where the site is located; or
ii. A proposed action meets alternative administrative standards pursuant to
this Section and the proposed activity results in no net loss of regulated riparian
area or shoreline ecological function in the drainage basin where the site is
located; or
iii. A variance process is successfully completed and the proposed activity
results in no net loss of regulated riparian area or shoreline ecological function in
the drainage basin where the site is located.
f. Incentives for Restoration of Streams Located in an Underground Pipe or
Culvert: Daylighting of culverted watercourses should be encouraged and allowed
with the following modified standards:
i. Residential Zones: Reduced setbacks, lot width and lot depth standards of
chapter 4-2 RMC may be approved without requirement of a variance for lots that
abut the daylighted watercourse to accommodate the same number of lots as if
the watercourse were not daylighted.
ii. Mixed Use, Commercial, and Industrial Zones: Where greater lot coverage
allowances are provided for structured parking in chapter 4-2 RMC, lot coverage
may be increased to the limit allowed for structured parking if instead a stream is
daylighted. The increase in impervious surface allowed shall be equal to the area
of stream restoration.
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(a) Standard buffers may be reduced pursuant to subsection I of this
Section. If reduced buffers in subsection I of this Section along with other
development standards of the zone would not allow the same development
level as without the watercourse daylighting, a modification may be requested
as in subsection I2c of this Section.
(b) When designed consistent with the City’s flood regulations in this
subsection G, portions of the daylighted stream/created buffer may be
considered part of compensatory storage in flood hazard areas.
(c) Stream relocation is permitted subject to subsection J of this Section.
78. Wellhead Protection Areas:
a. Applicability: Developments, facilities, uses and activities discussed in this
subsection shall comply with the applicable provisions and restrictions of this Section
and chapters 4-4, 4-5, 4-6, 4-9, and 5-5 RMC for the Wellhead Protection Areas, as
classified below, in which the developments, facilities, uses and activities are located,
except as preempted by Federal or State law.
i. Wellhead Protection Areas: Wellhead Protection Areas are the portion of an
aquifer within the zone of capture and recharge area for a well or well field owned
or operated by the City.
ii. Wellhead Protection Area Zones: Zones of a Wellhead Protection Area are
designated to provide graduated levels of Wellhead Protection Area recharge.
Zone boundaries are determined using best available science documented in the
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City of Renton Wellhead Protection Plan, an appendix of the City of Renton Water
System Plan, as periodically updated. The following zones may be designated:
(a) Zone 1: The land area situated between a well or well field owned by
the City and the three hundred sixty-five (365) day groundwater travel time
contour.
(b) Zone 1 Modified: The same land area described for Zone 1 but for the
purpose of protecting a high-priority well, wellfield, or spring withdrawing
from a confined aquifer with partial leakage in the overlying or underlying
confining layers. Uses, activities, and facilities located in this area are regulated
as if located within Zone 1 except as provided by this subsection G8.7.
(c) Zone 2: The land area situated between the three hundred sixty -five
(365) day groundwater travel time contour and the boundary of the zone of
potential capture for a well or well field owned or operated by the City. If the
aquifer supplying water to such a well, well field, or spring is naturally
protected by confining overlying and underlying geologic layers, the City may
choose not to subdivide a Wellhead Protection Area into two (2) zones. In such
a case, the entire Wellhead Protection Area will be designated as Zone 2.
iii. Mapping:
(a) Determination of Location within a Zone of a Wellhead Protection
Area: In determining the location of facilities within the zones, the following
rules shall apply:
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(1) Facilities located wholly within a Wellhead Protection zone shall be
governed by the restrictions applicable to that zone.
(2) Facilities having parts lying within more than one zone of a
Wellhead Protection Area shall be governed as follows: Each part of the
facility shall be reviewed and regulated by the requirements set forth in
this Section for the zone in which that part of the facility is actually located.
(3) Facilities having parts lying both in and out of a Wellhead Protection
Area shall be governed as follows:
(A) That portion which is within a Wellhead Protection Area shall
be governed by the applicable restrictions in this Section; and
(B) That portion which is not in a Wellhead Protection Area shall
not be governed by this Section.
b. Facilities:
i. Hazardous Materials – Use, Production, Storage, Treatment, Disposal, or
Management: Persons that store, handle, treat, use, or produce a hazardous
material as defined by RMC 4-11-080, Definitions H, which are new, existing, or to
be closed, shall be subject to the requirements of this Section, and as further
specified below:
(a) All applications for development permits for uses in which hazardous
materials are stored, handled, treated, used or produced or which increase the
quantity of hazardous materials stored, handled, treated, used, or produced
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at a location in the Wellhead Protection Area must be reviewed for compliance
with this chapter by the Department prior to approval.
(b) The focus of review for all permits will be on the hazardous materials
that will be stored, handled, treated, used, or produced; and the potential for
these substances to degrade groundwater quality.
(c) An inventory of hazardous materials on forms provided by the
Department shall be submitted to the Department upon application for a
development permit.
(d) Where required by the Department, plans and specifications for
secondary containment shall be submitted and shall comply with this
subsection G8.7. Development permits shall not be issued until plans and
specifications for secondary containment, if required, have been approved by
the Department.
ii. New Facilities – Zones 1 and 2: All proposals for new facilities within any
zone of an Wellhead Protection Area must be reviewed for compliance with this
Section prior to issuance of any development permits for uses in which hazardous
materials are stored, handled, treated, used or produced or which increase the
quantity of hazardous materials stored, handled, treated, used, or produced.
iii. Prohibited Facilities – Zone 1:
(a) The storage, handling, use, treatment or production of hazardous
materials in aggregate quantities greater than five hundred (500) gallons shall
not be allowed within Zone 1 of a Wellhead Protection Area. The storage,
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handling, use, treatment or production of tetrachloroethylene (e.g., dry-
cleaning fluid) shall not be allowed within Zone 1 of a Wellhead Protection
Area.
(b) No person, persons, corporation or other legal entity shall temporarily
or permanently abandon, close, sell, or otherwise transfer a facility in a
Wellhead Protection Area without complying with the requirements of RMC
4-9-015.F, Closure Permit, and permit conditions of this Section.
iv. Existing Facilities Change in Quantities – Zone 1: In Zone 1 of a Wellhead
Protection Area, no change in operations at a facility shall be allowed that
increases the aggregate quantity of hazardous materials stored, handled, treated,
used, or produced with the following exception: An increase in the quantity of
hazardous materials is allowed up to the amount allowed for a new facility in Zone
1 as provided by subsection C of this SectionRMC 4-3-050.C.
v. Existing Facilities – Allowances in Zone 2: The storage, handling, treatment,
use or production of hazardous materials at existing facilities shall be allowed
within Zone 2 of a Wellhead Protection Area upon compliance with the permit
requirements, release reporting requirements, and closure requirements of this
Section.
vi. Requirements for Facilities – Zones 1 and 2: The following conditions in
subsections G8bvi(a) to (d) of this SectionRMC 4-3-050.G.7.b.vi.a to d will be
required as part of any operating permit issued for facilities in Zone 1 of a
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Wellhead Protection Area. Conditions in subsections G8bvi(a) to (c)RMC 4-3-
050.G.7.b.vi.a to c shall apply to facilities in Zone 2 of a Wellhead Protection Area.
(a) Secondary Containment – Zones 1 and 2:
(1) Materials Stored in Tanks Subject to DOE – Zones 1 and 2:
Hazardous materials stored in tanks that are subject to regulation by the
Washington Department of Ecology under chapter 173-360 WAC are
exempt from containment requirements in subsection G.8.b.vi(a)(2) of this
SectionRMC 4-3-050.G.7.b.vi.a.2, Secondary Containment – Devices
Required in Zones 1 and 2, but are subject to applicable requirements in
RMC 4-5-120, Underground Storage Tank Secondary Containment
Regulations.
(2) Secondary Containment Devices Required in Zones 1 and 2: Every
owner of a facility shall provide secondary containment devices adequate
in size to contain on site any unauthorized release of hazardous materials
from any area where these substances are either stored, handled, treated,
used, or produced. Secondary containment devices shall prevent
hazardous materials from contacting soil, surface water, and groundwater
and shall prevent hazardous materials from entering storm drains and,
except for authorized and permitted discharges, the sanitary sewer.
(A) Design requirements for secondary containment devices are as
follows:
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(i) The secondary containment device shall be large enough to
contain the volume of the primary container in cases where a single
container is used to store, handle, treat, use, or produce a
hazardous material. In cases where multiple containers are used,
the secondary containment device shall be large enough to contain
the volume of the largest container. Volumes specified are in
addition to the design flow rate of the automatic fire extinguishing
system, if present, to which the secondary containment device is
subjected. The secondary containment device shall be capable of
containing the fire flow for a period of twenty (20) minutes or
more.
(ii) All secondary containment devices shall be constructed of
materials of sufficient thickness, density, and composition to
prevent structural weakening of the containment device as a result
of contact with any hazardous material. If coatings are used to
provide chemical resistance for secondary containment devices,
they shall also be resistant to expected abrasion and impact
conditions. Secondary containment devices shall be capable of
containing any unauthorized release for at least the maximum
anticipated period sufficient to allow detection and removal of the
release.
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(iii) Hazardous materials stored outdoors and their attendant
secondary containment devices shall be covered to preclude
precipitation with the exception of hazardous materials stored in
tanks that have been approved by and are under permit from the
Fire Department. Secondary containment for such tanks, if
uncovered, shall be able to accommodate the volume of
precipitation that could enter the containment device during a
twenty-four (24) hour, twenty-five (25) year storm, in addition to
the volume of the hazardous material stored in the tank.
(iv) Secondary containment devices shall include monitoring
procedures or technology capable of detecting the presence of a
hazardous material within twenty-four (24) hours following a
release.
(v) Hazardous materials shall be removed from the secondary
containment device within twenty-four (24) hours of detection and
shall be legally stored or disposed.
(vi) Areas in which there are floor drains, catchbasins, or other
conveyance piping that does not discharge into a secondary
containment device that meets the requirements of this chapter
shall not be used for secondary containment of hazardous
materials. Closure of existing piping shall be according to
procedures and designs approved by the Department.
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(vii) Primary containers shall be impervious to the contents
stored therein, properly labeled, and fitted with a tight cover which
is kept closed except when substances are being withdrawn or
used.
(viii) Hazardous materials stored outdoors when the facility is
left unsupervised must be inaccessible to the public. Such
techniques as locked storage sheds, locked fencing, or other
techniques may be used if they will effectively preclude access.
(ix) Stored hazardous materials shall be protected and secured,
as needed, against impact and earthquake to prevent damage to
the primary container that would result in release of hazardous
materials that would escape the secondary containment area.
(b) Monitoring Required: See RMC 4-9-015.
(c) Emergency Collection Devices – Zones 1 and 2: Vacuum suction
devices, absorbent scavenger materials, or other devices approved by the
Department shall be present on site (or available within an hour by contract
with a cleanup company approved by the Department), in sufficient quantity
to control and collect the total quantity of hazardous materials plus absorbent
material. The presence of such emergency collection devices and/or cleanup
contract are the responsibility and at the expense of the owner and shall be
documented in the operating permit.
(d) Additional Facility Requirements for Zone 1:
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(1) An owner of a facility may, at their own expense, be required to
institute a program to monitor groundwater, surface water runoff, and/or
site soils. The Department may require that the owner of a facility install
one or more groundwater monitoring wells in a manner approved by the
Department in order to accommodate the required groundwater
monitoring. Criteria used to determine the need for site monitoring shall
include, but not be limited to, the proximity of the facility to the City’s
production or monitoring wells, the type and quantity of hazardous
materials on site, and whether or not the hazardous materials are stored
in underground vessels.
(2) An owner may be required to pave all currently unpaved areas of
their facility that are subject to any vehicular use or storage, use, handling,
or production of hazardous materials.
(3) An owner may be required to meet the provisions of RMC 4-6-
030.E.4 if the nature of the business involves the use of hazardous
materials outside of fully enclosed structures, and the City evaluates the
existing stormwater collection and conveyance system.
(4) The owner may be required to test interior wastewater plumbing
and the building side sewer for tightness according to subsection G8gi(c)
of this SectionRMC 4-3-050.G.7.g.i.c, Pipeline Requirements – Zone
1Testing Required for New Pipelines, and the City reserves the right to
require that such wastewater conveyance be repaired or replaced
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according to subsection G8gi of this SectionRMC 4-3-050.G.7.g.i, Pipeline
Requirements – Zone 1.
(5) An owner shall be paid by the City fifty percent (50%) of
documented capital costs up to twenty-five thousand dollars ($25,000.00)
for required installation and construction of monitoring wells, site paving,
wastewater conveyance, and stormwater improvements as required in
subsections G8bvi(d)(1) through (4) of this Section, Groundwater
Monitoring and PavingRMC 4-3.050.G.7.b.vi.d.1 through 4. Payment by
the City shall be made according to adopted administrative rules.
c. Limited Exemptions: Activities that are exempt from some, but not all,
provisions of this Section are listed below. Whether the exempted activities are also
exempt from permits will be determined based upon application of chapters 4-8 and
4-9 RMC, or other applicable sections of the Renton Municipal Code.
i. Hazardous Materials:
(a) Materials for Sale in Original Small Containers: Hazardous materials
offered for sale in their original containers of five (5) gallons or less shall be
exempt from requirements in subsection G8bvi of this RMC 4-3-050.G.7.b.vi.
(b) Activities Exempt from Specified Wellhead Protection Areas
Requirements: The following are exempt from requirements in subsections
G8bvi(a) through (d) of this SectionRMC 4-3-050.G.7.b.vi.a through d, the
requirements pertaining to review of proposed facilities in subsection C5d of
this SectionRMC 4-3-050.C.5.c, Prohibited Changes in Land Use and Types of
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New Facilities – Wellhead Protection Areas, and the requirements pertaining
to prohibited facilities in subsection G8biii(a) of this SectionRMC 4-3-
050.G.7.b.iii.a:
(1) Hazardous materials use, storage, and handling in de minimis
amounts (aggregate quantities totaling twenty (20) gallons or less at the
facility or construction site). Weights of solid hazardous materials will be
converted to volumes for purposes of determining whether de minimis
amounts are exceeded. Ten (10) pounds shall be considered equal to one
gallon.
(2) Noncommercial residential use, storage, and handling of hazardous
materials; provided, that no home occupation business (as defined by
chapter 4-11 RMC) that uses, stores, or handles more than twenty (20)
gallons of hazardous material is operated on the premises.
(3) Hazardous materials in fuel tanks and fluid reservoirs attached to a
private or commercial motor vehicle and used directly in the operation of
that vehicle.
(4) Fuel oil used in existing heating systems.
(5) Hazardous materials used, stored, and handled by the City of
Renton in water treatment processes and water system operations.
(6) Fueling of equipment not licensed for street use; provided, that
such fueling activities are conducted in a containment area that is designed
and maintained to prevent hazardous materials from coming into contact
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with soil, surface water, or groundwater except for refueling associated
with construction activity regulated by RMC 4-4-030.C.8, Construction
Activity Standards – Zones 1 and 2.
(7) Hazardous materials contained in properly operating sealed units
(transformers, refrigeration units, etc.) that are not opened as part of
routine use.
(8) Hazardous materials in fuel tanks and fluid reservoirs attached to
private or commercial equipment and used directly in the operation of that
equipment.
(9) Hazardous materials in aerosol cans.
(10) Hazardous materials at multifamily dwellings, hotels, motels,
retirement homes, convalescent centers/nursing homes, mobile or
manufactured home parks, group homes, and daycare family homes or
centers when used by owners and/or operators of such facilities for on-
site operation and maintenance purposes.
(11) Hazardous materials used for janitorial purposes at the facility
where the products are stored.
(12) Hazardous materials used for personal care by workers or
occupants of the facility at which the products are stored including but not
limited to soaps, hair treatments, grooming aids, health aids, and
medicines.
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(c) Uses, Facilities, and Activities in Zone 1 Modified Wellhead Protection
Areas Exempt from Specified Wellhead Protection Areas Requirements:
Facilities located in the Zone 1 Modified Wellhead Protection Areas are
exempt from the following:
(1) Prohibited facilities requirements in subsection G8biii(a) of this
SectionRMC 4-3-050.G.7.b.iii.a except that the storage, handling, use,
treatment, and production of tetrachloroethylene (e.g., dry-cleaning fluid)
shall be prohibited;
(2) Additional facility requirements in subsection G8bvi(d) of this
SectionRMC 4-3-050.G.7.b.vi.d;
(3) Wastewater requirements in RMC 4-6-040.J.1.a but shall be subject
to Zone 2 requirements in RMC 4-6-040.J.2;
(4) The prohibition of septic systems; and
(5) Surface water management requirements of RMC 4-6-030.E except
that Zone 2 requirements contained in RMC 4-6-030.E shall apply.
d. Use of Pesticides and Nitrates – All Wellhead Protection Areas:
i. Use of Pesticides: The application of hazardous materials such as pesticides
shall be allowed in a Wellhead Protection Area, except within one hundred feet
(100') of a City owned well or two hundred feet (200') of a City owned spring;
provided, that:
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(a) The application is in strict conformity with the use requirements as set
forth by the EPA and as indicated on the containers in which the substances
are sold.
(b) Persons who are required to keep pesticide application records by RCW
17.21.100(1) and WAC 16-228-1320 shall provide a copy of the required
records to the Department within seventy-two (72) hours of the application.
ii. Fertilizers/Nitrate-Containing Materials: The application of fertilizers
containing nitrates shall be allowed in a Wellhead Protection Area except within
one hundred feet (100') of a City owned well or two hundred feet (200') of a
spring; provided, that:
(a) No application of nitrate-containing materials shall exceed one-half
(0.5) pound of nitrogen per one thousand (1,000) square feet per single
application and a total yearly application of five (5) pounds of nitrogen per one
thousand (1,000) square feet; except that an approved slow-release nitrogen
may be applied in quantities of up to nine-tenths (0.9) pound of nitrogen per
one thousand (1,000) square feet per single application and eight (8) pounds
of nitrogen per one thousand (1,000) square feet per year; and
(b) Persons who apply fertilizer containing nitrates to more than one
contiguous acre of land located in the Wellhead Protection Area either in one
or multiple application(s) per year shall provide to the Department within
seventy-two (72) hours of any application the following information:
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(1) The name, address, and telephone number of the person applying
the fertilizer;
(2) The location and land area of the application;
(3) The date and time of the application;
(4) The product name and formulation;
(5) The application rate.
e. Wastewater Disposal Requirements – Zones 1 and 2: Refer to RMC 4-6-040.J,
Sanitary Sewer Standards, Additional Requirements that Apply within Zones 1 and 2
of an Aquifer Protection Area.
f. Surface Water Requirements – Zones 1 and 2: Refer to RMC 4-6-030.E, drainage
plan requirements and methods of analysis for additional surface water requirements
applicable within Zones 1 and 2 of a Wellhead Protection Area.
g. Pipeline Requirements:
i. Pipeline Requirements – Zone 1:
(a) Materials: All new and existing pipelines, as defined by RMC 4-11-160,
in Zone 1 shall be constructed or repaired in accordance with material
specifications contained in this Section.
(b) Maintenance Required for Existing Pipelines: All existing product
pipelines in Zone 1 shall be repaired and maintained in accordance with best
management practices and best available technology.
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(c) Testing Required for New Pipelines: All new pipelines constructed in
Zone 1 shall be tested for leakage in conformance with the following
provisions prior to being placed into service.
(1) Pipeline leakage testing shall be conducted in accordance with best
available technology, to the satisfaction of the Department.
(2) Pipeline leakage testing methods shall be submitted to the
Department for review prior to testing and shall include a detailed
description of the testing methods and technical assumptions; accuracy
and precision of the test; proposed testing durations, pressures, and
lengths of pipeline to be tested; and scale drawings of the pipeline(s) to be
tested.
(3) Upon completion of testing, pipeline leakage testing results shall be
submitted to the Department and shall include: record of testing
durations, pressures, and lengths of pipeline tested; and weather
conditions at the time of testing.
(4) Routine leakage testing of new pipelines constructed in Zone 1 may
be required by the Department.
h. Construction Activity Standards – Zones 1 and 2: Persons engaged in
construction activities as defined in RMC 4-11-030, Definitions C, shall comply with
subsection G8 of this SectionRMC 4-3-050.G.7.
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i. Fill Material Requirements – Zones 1 and 2: Refer to RMC 4-4-060.N.4, Fill
Material – Zones 1 and 2, regarding quality of fill and fill material source statement
requirements within Critical Aquifer Recharge Areas.
j. Regulations for Existing Solid Waste Landfills – Zones 1 and 2:
i. Materials: Earth materials used as fill or cover at a solid waste landfill shall
meet the requirements of RMC 4-4-060.N.4, Fill Material.
ii. Groundwater Monitoring: The Department shall have the authority to
require an owner of a solid waste landfill to implement a groundwater monitoring
program equal to that described by King County Board of Health Title 10 (King
County Solid Waste Regulations) Section 10.72.020 and a corrective action
program equal to that described by Section 10.72.030. The Department shall have
the authority ascribed to the health officer in said regulations. Quarterly reports
shall be provided to the Department detailing groundwater monitoring activity
during the preceding three (3) months. Reports detailing corrective action
required by the Department shall be submitted according to a written schedule
approved by the Department.
k. Fuel Oil Heating Systems – Zones 1 and 2: Owners of facilities and structures
shall comply with subsections C5cii(i) and C5ciii(f) of this SectionRMC 4-3-050.C.5.i
and ii, Prohibited Activities – Wellhead Protection Areas, Zones 1 and 2, relating to
conversion of heating systems to fuel oil and installation of new fuel oil heating
systems.
9. Wetlands:
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a. Applicability: Wetland regulations apply to sites containing or abutting
wetlands, defined in RMC 4-11-230, as described below. The City categorizes wetlands
according to the most current version of the Washington State Wetland Rating System
for Western Washington.
b. Delineation of Regulatory Edge of Wetlands:
i. Methodology: For the purpose of regulation, the exact location of the
wetland edge shall be determined by the wetlands specialist qualified professional
hired at the expense of the applicant through the performance of a field
investigation in accordance with the approved federal wetland delineation
manual and applicable regional supplements.
ii. Adjustments to Delineation by City: Where the applicant has provided a
delineation of the wetland edge, the City shall review and may render adjustments
to the edge delineation. In the event the adjusted edge delineation is contested
by the applicant, the City shall, at the applicant’s expense, obtain the services of
an additional qualified wetlands specialist professional to review the original study
and render a final delineation.
c. Wetland Categorization or Categorization System: The following categorization
system is hereby adopted for the purposes of regulating wetlands in the City. The City
may accept a dual wetland categorization for a wetland exhibiting a combination of
Category I and II features or a combination of Category I and III features. The City will
not accept a dual rating for a Category II wetland, such as a combined Category II and
III rating. Dual ratings for a Category I wetland shall be consistent with the Washington
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State Wetland Rating System for Western Washington – 2014 Update (October 2014),
or as amended hereafter. Wetlands buffer widths, replacement ratios and avoidance
criteria shall be based on Wetland Mitigation in Washington State, Part 1: Agency
Policies and Guidance, Version 2 (Ecology Publication No. 21-06-003, April 2021) and
the following ratings:
i. Category I Wetlands: Category I wetlands are those wetlands of exceptional
value in terms of protecting water quality, storing flood and stormwater, and/or
providing habitat for wildlife as indicated by a rating system score of twenty -three
(23) points or more on the state rating system referenced above. These are
wetland communities of infrequent occurrence that often provide documented
habitat for critical, threatened or endangered species, and/or have other
attributes that are very difficult or impossible to replace if altered.
ii. Category II Wetlands: Category II wetlands have significant value based on
their function as indicated by a rating system score of between twenty (20) and
twenty -two (22) points the state rating system referenced above. They do not
meet the criteria for Category I rating but occur infrequently and have qualities
that are difficult to replace if altered.
iii. Category III Wetlands: Category III wetlands have important resource value
as indicated by a rating system score of between sixteen (16) and nineteen (19)
points the state rating system referenced above.
iv. Category IV Wetlands: Category IV wetlands are wetlands of limited
resource value as indicated by a rating system score between nine (9) and fifteen
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(15) points the state rating system referenced above. They typically have
vegetation of similar age and class, lack special habitat features, and/or are
isolated or disconnected from other aquatic systems or high -quality upland
habitats.
d. Wetland Buffers:
i. Standard Buffer Widths: See subsection G2 of this Section, Critical Area
Buffers and Structure Setbacks from Buffers.
ii. Independent Buffer Study: The Administrator shall have the authority to
approve proposed alternate buffer widths based on a qualified professional’s
wetland study, provided the criteria below are met. Determinations made by the
Administrator pursuant to this subsection may be appealed to the Hearing
Examiner.
(a) The applicant funds the wetland study; and
(b) The wetland study shows why the standard buffer widths are
unnecessary and how the proposed alternate buffer will provide an equivalent
ecological protection as provided by the City standards; and
(c) The wetland study demonstrates how it meets best available science as
identified in Wetlands in Washington State, Volume 1: A Synthesis of the
Science (Ecology Publication No. 05-06-006, March 2005), and Wetlands in
Washington State, Volume 2: Managing and Protecting Wetlands (Ecology
Publication No. 04-06-008, April 2005), Wetland Mitigation in Washington
State Part 1: Agency Policies and Guidance, Version 2 (Ecology Publication No.
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21-06-003, April 2021), and Calculating Credits and Debits for Compensatory
Mitigation in Wetlands of Western Washington (Ecology Publication No. #10-
06-011, March 2012).
iii. Measurement of Buffers: All buffers shall be measured from the wetland
boundary as surveyed in the field pursuant to the requirements of this subsection.
iv. Increased Wetland Buffer Width: Each applicant shall document in the
required wetland assessments whether the criteria in this subsection G9d are or
are not met and increased wetland buffers are warranted. Based on the
applicant’s report or third- party review, increased standard buffer widths may be
required in unique cases. Such determination shall be attached as a condition of
project approval. Unique cases shall include but not be limited to:
(a) The wetland is used by species listed by the Federal or the State
government as threatened, endangered and sensitive species and State-listed
priority species, essential habitat for those species or has unusual nesting or
resting sites such as heron rookeries or raptor nesting trees or evidence
thereof; or
(b) The buffer or adjacent uplands have a slope greater than fifteen
percent (15%) or is susceptible to erosion and standard erosion control
measures will not effectively prevent adverse wetland impacts; or.
(c) The area is very fragile, or Wwhen a larger buffer is necessary to protect
wetlands functions and values.
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e. Cooperative Wetland Compensation: Mitigation Banks, In-Lieu Fee Programs,
or Special Area Management Programs (SAMP):
i. Applicability: The City encourages and will facilitate and approve
cooperative projects wherein a single applicant or other organization with
demonstrated capability may undertake a compensation project under the
following circumstances:
(a) Restoration or creation on site may not be feasible due to problems
with hydrology, soils, or other factors; or
(b) Where the cooperative plan is shown to better meet established
regional goals for flood storage, flood conveyance, habitat or other wetland
functions.
ii. Process: Applicants proposing a cooperative compensation project shall:
(a) Submit a permit application;
(b) Demonstrate compliance with all standards;
(c) Demonstrate that long-term management will be provided; and
(d) Demonstrate agreement for the project from all affected property
owners of record.
iii. Mitigation Banks: Mitigation banks are defined as sites which may be used
for restoration, creation and/or mitigation of wetland alternatives from a different
piece of property than the property to be altered within the same drainage basin.
The City of Renton maintains a mitigation bank. A list of City mitigation bank sites
is maintained by the Public Works Department. With the approval of
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Administrator and the Public Works Department, non-City-controlled mitigation
banks may be established and utilized. If credits are from a mitigation bank are to
be used for Federal or State permits, the bank must be certified under State rules.
If approved, compensation payments received as part of a mitigation or creation
bank must be received prior to the issuance of an occupancy permit.
iv. In-Lieu Fee Programs: In-lieu fee mitigation involves the restoration,
creation, enhancement, or preservation of aquatic resources through funds paid
to a governmental or non-profit natural resources management entity to satisfy
compensatory mitigation for Federal, State, and local permits. Both the U.S. Army
Corps of Engineers (33 CFR Parts 325 and 332) and Washington State (WAC 173-
700) support the use of in-lieu fee programs. The City of Renton is located within
the service area of the King County Mitigation Reserves In-Lieu Fee Program,
which may be used by applicants with the approval of the Administrator and Public
Works Department provided the mitigation occurs within the City of Renton and
the same drainage basin.
v. Special Area Management Programs: Special area management programs
are those wetland programs agreed upon through an interjurisdictional planning
process involving the U.S. Army Corps of Engineers, the Washington State
Department of Ecology, any affected counties and/or cities, private property
owners and other parties of interest. The outcome of the process is a regional
wetlands permit representing a plan of action for all wetlands within the special
area.
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SECTION XII. Section 4-3-050.H.3 of the RMC is amended as follows:
3. Studies Required: The City’s determination shall be based on specific site studies
by recognized experts. Impacts and mitigation shall be based on consideration of
Wetland Mitigation in Washington State Part 1: Agency Policies and Guidance, Version 2
(Ecology Publication No. 21-06-003, April 2021) and Calculating Credits and Debits for
Compensatory Mitigation in Wetlands of Western Washington (Ecology Publication No.
#10-06-011, March 2012) or as amended hereafter.
SECTION XIII. Section 4-3-050.I.1 of the RMC is amended as follows:
1. Maximum Permissible Administrative Alterations to Critical Areas Buffers –
Alteration of Critical Area Buffers: The required critical area buffers may be reduced to
no less than the minimums set forth in this subsection. Greater buffer width reductions
require review as a variance pursuant to RMC 4-9-250.
Table 4-3-050.I.1 Alterations Table
Critical Area Category or Type Reduced Buffer: Minimum
Widths Possible
Averaged Buffer: Minimum
Widths Possible
Geologically Hazardous Areas
Landslide Hazard Areas:
Very High Based on City acceptance of a
geotechnical report1 N/A
Streams and Lakes
Type F 90 feet2 75 feet3
Type Np 60 feet2 37.5 feet3
Type Ns 40 feet2 25 feet3
Wetlands
Wetland buffer widths shall be reduced by no more than 25% of the buffer required in
subsection G of this SectionRMC 4-3-050.G.
Footnotes:
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1. Subject to approval pursuant to the criteria in RMC 4-3-050.G.5.h.ii.
2. Subject to approval pursuant to the criteria in RMC 4-3-050.I.2.a.
3. Subject to approval pursuant to the criteria in RMC 4-3-050.I.2.b.
SECTION XIV. Section 4-3-050.I.3 of the RMC is amended as follows:
3. Wetlands:
a. Criteria for Reduction of Wetland Buffer Width with Enhancement: The
reviewing official must find that the proposal meets all the following criteria:
i. The reduced buffer will function at a higher level than the standard buffer;
and
ii. An enhanced buffer shall never be less than seventy five percent (75%) of
the standard width at its narrowest point; and
iii. The buffer area has less than fifteen percent (15%) slopes and no direct or
indirect, short-term or long-term, adverse impacts to regulated wetlands, as
determined by the City,; and
iv. The proposal shall rely upon a site-specific evaluation and documentation
of buffer adequacy based upon Wetlands in Washington State, Volume 1: A
Synthesis of the Science (Ecology Publication No. 05-06-006, March 2005), and
Wetlands in Washington State, Volume 2: Managing and Protecting Wetlands
(Ecology Publication No. 04-06-008, April 2005), and Wetland Mitigation in
Washington State Part 1: Agency Guidance, Version 2 (Ecology Publication No. 21-
06-003, April 2021), or as amended hereafter, or similar approaches; and
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v. The proposed buffer standard is based on consideration of the best available
science as described in WAC 365-195-905; and
b. Criteria for Averaging of Wetland Buffer Width: Averaging may be allowed only
where the applicant demonstrates all of the following:
i. There are existing physical improvements in or near the wetland and buffer;
and
ii. That width averaging will not adversely impact the wetland function and
values; and
iii. That the total area contained within the wetland buffer after averaging is
no less than that contained within the required standard buffer prior to averaging;
and
iv. A site-specific evaluation and documentation of buffer adequacy based
upon Wetlands in Washington State, Volume 1: A Synthesis of the Science (Ecology
Publication No. 05-06-006, March 2005), and Wetlands in Washington State,
Volume 2: Managing and Protecting Wetlands (Ecology Publication No. 04-06-008,
April 2005), and Wetland Mitigation in Washington State Part 1: Agency Guidance,
Version 2 (Ecology Publication No. 21-06-003, April 2021), or as amended
hereafter, or similar approaches, have been conducted. The proposed buffer
standard is based on consideration of the best available science as described in
WAC 365-195-905; and
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v. In no instance shall the buffer width be reduced by more than seventy five
percent (75%) of the standard buffer. Greater buffer width reductions require
review as a variance pursuant to RMC 4-9-250.B; and
vi. Buffer enhancement in the areas where the buffer is reduced shall be
required on a case-by-case basis where appropriate to site conditions, wetland
sensitivity, and proposed land development characteristics.
SECTION XV. Section 4-3-050.J.2.a of the RMC is amended as follows:
2. Alterations Within Streams and Lakes or Associated Buffers.
a. Criteria for Administrative Approval of Transportation Crossings in
Stream/Lake or Buffer Areas: Construction of vehicular or non-vehicular
transportation crossings may be permitted in accordance with an approved
stream/lake study subject to the following criteria:
i. The proposed route is determined to have the least impact on the
environment, while meeting City Comprehensive Plan Transportation Element
requirements and standards in RMC 4-6-060; and
ii. The crossing minimizes interruption of downstream movement of wood and
gravel; and
iii. Transportation facilities in buffer areas shall not run parallel to the water
body; and
iv. Crossings occur as near to perpendicular with the water body as possible;
and
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v. Crossings are designed according to the Washington Department of Fish and
Wildlife Fish Water Crossing Design Guidelines (2013) and the National Marine
Fisheries Service (NMFS) 2022 Guidelines for Salmonid Passage at Stream
Crossings in Oregon, Washington, and Idaho. These guidelines National Marine
Fisheries Service Guidelines for Salmonid Passage at Stream Crossings, 2000, as
may be updated, or replaced by equivalent manuals as determined by the
Administrator; and
vi. Seasonal work windows are determined and made a condition of approval;
and
vii. Mitigation criteria of subsection L of this SectionRMC 4-3-050.L are met.
SECTION XVI. Section 4-3-050.J.4 of the RMC is amended as follows:
4. Criteria for Approving Wetland Alterations: Wetland alterations may only be
authorized after the City makes a written finding that the proposal is consistent with the
following criteria:
a. No Net Loss: Activities that adversely affect wetlands and/or wetland buffers
shall include mitigation sufficient to achieve no net loss of wetland function and
acreage and to achieve, where practicable, a net resource gain in wetlands over
present conditions. The concept of “no net loss” means to create, restore and/or
enhance a wetland so that there is no reduction to total wetland acreage and/or
function.
b. Compensation for wetland alterations shall occur in the following order of
preference:
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i. Re-establishing wetlands on upland sites that were formerly wetlands.
ii. Rehabilitating wetlands for the purposes of repairing or restoring natural
and/or historic functions.
iii. Creating wetlands on disturbed upland sites such as those consisting
primarily of nonnative, invasive plant species.
iv. Enhancing significantly degraded wetlands.
iv. Preserving Category I or II wetlands that are under imminent threat;
provided, that preservation shall only be allowed in combination with other forms
of mitigation and when the Administrator determines that the overall mitigation
package fully replaces the functions and values lost due to development.
v. Enhancing significantly degraded wetlands.
vi. Cooperative compensation to mitigation banks or in-lieu fee programs, as
indicated in subsection G9e of this SectionRMC 4-3-050.G.2.p.
c. Mitigation Ratios for Wetland Impacts: Compensatory mitigation for wetland
alterations shall be based on the wetland category and the type of mitigation activity
proposed. The replacement ratio shall be determined according to the ratios provided
in the table(s) below. The created, re-established, rehabilitated, preserved, or
enhanced wetland area shall at a minimum provide a level of functions equivalent to
the wetland being altered and shall be located in an appropriate landscape setting.
Table 4-3-050.J.4.c Mitigation Tables
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Wetland Mitigation Type and Replacement Ratio*
Wetland
Category**
Creation or Re-
establishment Rehabilitation Preservation Enhancement
Only
Category IV 1.5:1*** 2:13:1 6:1 3:16:1
Category III 2:1 3:14:1 8:1 4:18:1
Category II 3:1 4:16:1 12:1 12:16:1
Category I 6:14:1 8:1 16:1 Not allowed 16:1
Combined Wetland MiƟgaƟon Type and CompensaƟon RaƟos*
Wetland Category**
Re-establishment or
CreaƟon (R/C) Plus
RehabilitaƟon (RH)
Re-establishment or
CreaƟon (R/C) Plus
PreservaƟon
(P)****
Re-establishment or
CreaƟon (R/C) Plus
PreservaƟon (P)1
Category
IV
1:1 R/C plus
1:1RH***
1:1 R/C plus 2:1 P 1:1 R/C plus 2:1 E
Category
III
1:1 R/C plus 2:1 RH 1:1 R/C plus 4:1 P 1:1 R/C plus 4:1 E
Category
II
1:1 R/C plus 4:1 RH 1:1 R/C plus 8:1 P 1:1 R/C plus 8:1 E
Category
I
1:1 R/C plus 6:1 RH 1:1 R/C plus 12:1 P 1:1 R/C plus 12:1 E
*Ratio is the replacement area: impact area.
**As defined in RMC 4-3-050.G.
***These ratios do not apply to impacts to wetlands with special
characteristics.
****Consistent with Wetland Mitigation in Washington State, Part 1: Agency Policies and
Guidance, Version 2 (Ecology Publication No. 21-06-003, April 2021) or as amended
hereafter.
d. Mitigation Ratios for Wetland Buffer Impacts: Compensation for wetland
buffer impacts shall occur at a minimum one to one (1:1) ratio. Compensatory
mitigation for buffer impacts shall include enhancement of degraded buffers by
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planting native species, removing structures and impervious surfaces within buffers,
and other measures.
e. Special Requirements for Mitigation Banks: Mitigation banks shall not be
subject to the replacement ratios outlined in the replacement ratio table above, but
shall be determined as part of the mitigation banking agreement and certification
process.
f. Buffer Requirements for Replacement Wetlands: Replacement wetlands
established pursuant to these mitigation provisions shall have adequate buffers to
ensure their protection and sustainability. The buffer shall be based on the category
in subsection G2 of this SectionRMC 4-3-050.G.2.
g. Location: Compensatory mitigation shall be provided on site or off site in the
location that will provide the greatest ecological benefit and have the greatest
likelihood of success. Mitigation shall occur as close as possible to the impact area,
within the same watershed sub-basin, and in a similar habitat type as the permitted
alteration unless the applicant demonstrates to the satisfaction of the Administrator
through a watershed- or landscaped-based analysis that mitigation within an
alternative sub-basin of the same watershed would have greater ecological benefit.
h. Protection: All mitigation areas whether on or off site shall be permanently
protected and managed to prevent degradation and ensure protection of critical area
functions and values into perpetuity. Permanent protection shall be achieved through
protective covenant in accordance with this Section.
SECTION XVII. Section 4-3-050.L.1.a of the RMC is amended as follows:
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1. Mitigation Plan Required:
a. Criteria: Mitigation plans required through the application of subsections G4 to
G9 of this SectionRMC 4-3-050.G.2 and 4-3-050.G.4 through G.7 shall comply with
chapter 4-8 RMC. In addition, the applicant shall:
i. Demonstrate sufficient scientific expertise, the supervisory capability, and
the financial resources to carry out the mitigation project; and
ii. Demonstrate the capability for monitoring the site and making corrections
during the monitoring period if the mitigation project fails to meet projected
goals; and
iii. Protect and manage, or provide for the protection and management, of the
mitigation area to avoid further development or degradation and to provide for
long-term environmental health of the mitigation area; and
iv. Provide for project monitoring and allow City inspections on a schedule
determined by the City; and
v. Avoid mitigation proposals that would result in additional future mitigation
or regulatory requirements for adjacent or abutting properties.
SECTION XVIII. Section 4-3-050.L.1.b of the RMC is amended as follows:
b. Mitigation Sequencing: If alterations to critical areas are proposed for a non-
exempt activity, the applicant shall evaluate alternative methods of developing the
property using the following criteria in this order and provide reasons why a less
intrusive method of development is not feasible. In determining whether to grant
permit approval pursuant to RMC 4-3-050.C, a determination shall be made as to
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whether the feasibility of less intrusive methods of development has been adequately
evaluated and that less intrusive methods of development are not feasible.
i. Avoiding the impact altogether by not taking a certain action or parts of an
action (usually by either finding another site or changing the location on the site).
ii. Minimizing adverse impacts by limiting the magnitude of the action and its
implementation, by using appropriate technology, or by taking affirmative steps,
such as project redesign, relocation, or timing, to avoid or reduce impacts.
iii. Rectifying adverse impacts to wetlands, Wellhead Protection Areas, flood
hazard areas, and fish and wildlife habitat conservation areas by repairing,
rehabilitating, or restoring the affected environment to the historical conditions
or the conditions existing at the time of the initiation of the project.
iv. Minimizing or eliminating the hazard by restoring or stabilizing the hazard
area through engineered or other methods.
v. Reducing or eliminating the adverse impacts or hazard over time by
preservation and maintenance operations over the life of the action.
vi. Compensating for adverse impacts to wetlands, Wellhead Protection Areas,
flood hazard areas, and fish and wildlife habitat conservation areas by replacing,
enhancing, or providing substitute resources or environments.
vii. Monitoring the hazard or other required mitigation and taking remedial
action when necessary.
SECTION XIX. Section 4-3-050.L.1.g of the RMC is amended as follows:
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g. When Stream or Lake Mitigation Plan Is Required: The applicant shall be
required to conduct a stream or lake mitigation plan pursuant to RMC 4-8-120 if
impacts are identified within a stream or lake study. The approval of the stream or
lake mitigation plan by the Administrator shall be based on the following criteria.
i. Mitigation Location: Mitigation location shall follow the preferences in this
subsection L:
(a) On-Site Mitigation: On-site mitigation is required unless a finding is
made that on-site mitigation is not feasible or desirable;
(b) Off-Site Mitigation within Same Drainage Subbasin as Subject Site:
Off-site mitigation may be allowed when located within the same drainage
subbasin as the subject site and if it achieves equal or improved ecological
functions over mitigation on the subject site;
(c) Off-Site Mitigation within Same Drainage Basin within City Limits:
Off-site mitigation may be allowed when located within the same drainage
basin within the Renton City limits if it achieves equal or improved
ecological functions within the City over mitigation within the same
drainage subbasin as the project;
(d) Off-Site Mitigation within the Same Drainage Basin Outside the
City Limits: Off-site mitigation may be allowed when located within the
same drainage basin outside the Renton City limits if it achieves equal or
improved ecological functions over mitigation within the same drainage
basin within the Renton City limits and it meets City goals.
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ii. Mitigation Type: In all cases, mitigation shall provide for equivalent or
greater biological functions pursuant to subsection L1giii(a) of this SectionRMC 4-
3-050.L.1.g.iii.a. Additionally, there shall be no net loss of riparian area or
shoreline ecological function resulting from any activity or land use occurring
within the regulated buffer area. Types of mitigation shall follow the preferences
in this subsection L:
(a) Daylighting (returning to open channel) of streams or removal of
manmade salmonid migration barriers;
(b) Removal of impervious surfaces in buffer areas and improved
biological function of the buffer;
(c) In-stream or in-lake mitigation as part of an approved watershed
basin restoration project;
(d) Other mitigation suitable for site and water body conditions that
meet all other provisions for a mitigation plan.
iii. Contiguous Corridors: Mitigation sites shall be located to preserve or
achieve contiguous riparian or wildlife corridors to minimize the isolating effects
of development on habitat areas, so long as mitigation of aquatic habitat is located
within the same aquatic ecosystem as the area disturbed.
(a) Equivalent or Greater Biological Functions: The Administrator shall
utilize the report “City of Renton Best Available Science Literature Review
and Stream Buffer Recommendations” by AC Kindig and Company and
Cedarock Consultants, dated February 27, 2003 the Washington
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Department of Fish and Wildlife’s Best Available Science document,
“Riparian Ecosystem, Volume 1: Science Synthesis and Management
Implications,” and management recommendations document, “Riparian
Ecosystems, Volume 2: Management Recommendations”, or as amended
hereafter, unless superseded with a City-adopted study, to determine the
existing or potential ecological function of the stream or lake or riparian
habitat that is being affected. Alternate reports or literature that meet
Best Available Science may be utilized as supplemental information in
order to ensure the Administrator’s determination reflects current science
and analysis. Mitigation shall address each function affected by the
alteration. Mitigation to compensate alterations to stream/lake areas and
associated buffers shall achieve equivalent or greater biologic and
hydrologic functions and shall include mitigation for adverse impacts
upstream or downstream of the development proposal site. No net loss of
riparian habitat or water body function shall be demonstrated.
(b) Minimum Mitigation Plan Performance Standards: See subsection
L1 of this SectionRMC 4-3-050.L.1.
iv. Alternative Mitigation: The mitigation requirements set forth in this
subsection L.1 may be modified at the Administrator’s discretion if the applicant
demonstrates that improved habitat functions, on a per-function basis, can be
obtained in the affected sub-drainage basin as a result of alternative mitigation
measures.
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SECTION XX. Section 4-3-050.N.3 of the RMC is amended as follows:
3. Minimum Performance Standards for Restoration: Information demonstrating
compliance with the requirements in subsection L of this SectionRMC 4-3-050.L.1 shall be
submitted to the Administrator. The following minimum performance standards shall be
met for the restoration of a critical area; provided, that if the violator can demonstrate
that greater functional and habitat values can be obtained, these standards may be
modified:
a. Wellhead Protection Areas, Flood Hazard Areas, Wetlands, and Fish and
Wildlife Habitat Conservation Areas:
i. The historic structural and functional values shall be restored, including
water quality and habitat functions;
ii. The historic soil types and configuration shall be replicated;
iii. The critical area and buffers shall be replanted with native vegetation that
replicates the vegetation historically found on the site in species types, sizes, and
densities. The historic functions and values should be replicated at the location of
the alteration; and
b. Geologic Hazards:
i. The hazard shall be reduced to a level equal to, or less than, the pre-
development hazard; and
ii. Any rRisk of personal injury resulting from the alteration shall be eliminated
or minimized; and
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iii. The hazard area and buffers shall be replanted with native vegetation
sufficient to minimize the hazard.
SECTION XXI. Section 4-11-030 of the RMC is amended as follows:
LLL. CRITICAL AQUIFER RECHARGE AREA: Areas, defined under the provisions of
the Growth Management Act as areas with a critical recharging effect on aquifers used
for potable water, including those areas designated as wellhead protection areas and
aquifer protection areas in accordance with RMC 4-11-010 and RMC 4-11-230
LLLMMM. CRITICAL FACILITY: A facility for which even a slight chance of flooding, high
geologic hazard, or inundation in the areas of flood hazard or volcanic hazard might be
too great. Critical facilities include, but are not limited to, schools, nursing homes,
hospitals, police, fire and emergency response installations, and facilities that produce,
use or store hazardous materials or hazardous waste.
MMMNNN. CRITICAL HABITAT or CRITICAL WILDLIFE HABITAT: Habitat areas associated
with threatened, endangered, sensitive, monitored, or priority species of plants or wildlife
and which, if altered, could reduce the likelihood that the species would maintain and
reproduce over the long term. See also RMC 4-3-050.
NNNOOO. CROSS CONNECTION: See RMC 4-6-100.
OOOPPP. CUL-DE-SAC: A vehicular turn-around at the end of a dead end street.
PPPQQQ. CULTURAL FACILITIES: Facilities which offer passive entertainment and
enjoyment activities to the general public. This definition includes, but is not limited to,
museums and libraries. This definition excludes adult entertainment businesses; dance
halls; dance clubs; religious institutions; and gaming/gambling facilities.
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QQQRRR. CURB: A vertical curb and gutter section constructed from concrete.
SECTION XXII. Subsection 4-11-040.L of the RMC is amended as follows:
L. DENSITY, NET: A calculation of the number of housing units and/or lots that would be
allowed on a property after critical areas, i.e., very high landslide hazard areas, protected
slopes (except evaluate on a case-by-case basis those protected slopes created by
previous development), wetlands, Type F, Type Np, and Type Ns waterbodies, Class 1 to
4 streams and lakes, or floodways, and public rights-of-way and legally recorded private
access easements, are subtracted from the gross area (gross acres minus streets and
critical areas multiplied by allowable housing units per acre). Developments meeting the
definition of a shopping center are not required to deduct areas within access easements
from the gross site area for the purpose of calculating net density. Required critical area
buffers, streams that have been daylighted including restored riparian and aquatic areas,
public and private alleys, unit lot drives, drives, joint use driveways (and the access
easements upon them), and trails shall not be subtracted from gross acres for the purpose
of net density calculations. All fractions which result from net density calculations shall
be truncated at two (2) numbers past the decimal (e.g., 4.5678 becomes 4.56).
Calculations for minimum or maximum density which result in a fraction that is one-half
(0.50) or greater shall be rounded up to the nearest whole number. Those density
calculations resulting in a fraction that is less than one-half (0.50) shall be rounded down
to the nearest whole number.
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SECTION XXIII. Section 4-11-190.B of the RMC is amended as follows:
B. SALMONID MIGRATION BARRIER: An in-stream blockage that consists of a natural
drop (no human influence) with an uninterrupted slope greater than one hundred percent
(100%) (forty five (45) degree angle) and a height in excess of eleven (11) vertical feet
within anadromous salmon-bearing waters or a height in excess of three (3) vertical feet
within resident trout-only bearing waters. Human-made barriers to salmonid migration
(e.g., culverts, weirs, etc.) shall be considered barriers to salmonid migration by this
definition, only if they were lawfully installed; permanent; present a complete barrier to
salmonid passage based on hydraulic drop, water velocity, water depth, or any other
feature which would prevent all salmonids from passing upstream; and in the opinion of
the Community and Economic Development Administrator cannot be modified to provide
salmonid passage without resulting in significant impacts to other environmental
resources, major transportation and utility systems, or to the public, and would have
significant expense. For the purposes of this definition, “significant expense” means a cost
equal to or greater than fifty percent (50%) of the combined value of the proposed site
buildings, structures, and/or site improvements, and existing buildings, structures, and/or
site improvements to be retained.