ORD 21-922 - Adopting 2021 KCSWDMORDINANCE NO.21-922
AN ORDINANCE of the City of Federal Way, Washington, relating to
National Pollutant Discharge Elimination System Phase II Permit
Requirements; amending FWRC 16.20.010 and 16.25.010 (Amending
Ordinance Nos. 99-352, 09-630,16-828).
WHEREAS, the Washington State Department of Ecology issued the Western Washington
Phase II Municipal Stormwater Permit ("NPDES Permit") on July 1, 2019 pursuant to the
requirements of the Federal Clean Water Act ("CWA") —National Pollutant Discharge Elimination
System ("NPDES"); and
WHEREAS, the NPDES Permit requires affected cities and counties, such as the City of
Federal Way ("City"), to adopt Storm Water Design Requirements consistent with the terms of the
NPDES permit; and
WHEREAS, the NPDES Permit requires the City to adopt a Stormwater Manual, which may
be either the State of Washington (Department of Ecology) manual, a Phase I Permit holder (King
County) manual, or a manual created by the City; and
WHEREAS, currently the City has adopted the 2016 King County, Washington Surface
Water Design Manual ("KCSWDM"); and
WHEREAS, on July 23, 2021, King County released an update to the KCSWDM; and
WHEREAS, as a Phase II permit holder, the City must adopt the updated KCSWDM by
December 31, 2021; and
WHEREAS, the proposed regulatory code amendments will serve to better protect the City's
natural water resources in terms of both water quality and water quantity; and
Ordinance No. 21-922 Page I of 8
WHEREAS, the City Council of the City of Federal Way finds it in the best interest of the
City to modify the regulatory code to meet the NPDES Permit requirements and that amending this
section is consistent with the applicable provisions of the comprehensive plan; and is in the best
interest of the residents of the City; and
WHEREAS, the City Council desires to adopt the 2021 Federal Way Addendum to the King
County, Washington Surface Water Design Manual, which is attached and incorporated by this
reference.
NOW, THEREFORE, THE CITY COUNCIL OF THE CITY OF FEDERAL WAY,
WASHINGTON, DO ORDAIN AS FOLLOWS:
Section 1. FWRC 16.20.010 is hereby amended to read as follows:
16.20.010 Manuals and addendum adopted.
The 24�6 current version of the King County, Washington Surface Water Design Manual
(KCSWDM), the current accompanying version of thee -Federal Way Addendum to the King
County, Washington Surface Water Design Manual, the King County Stormwater Pollution
Prevention Manual, and the latest edition of the LID Technical Guidance Manual for Puget Sound, as
they exist on the effective date of the ordinance codified in this chapter or as hereafter amended, are
hereby adopted by this reference. They are referred to in this title respectively as the KCSWDM,
Federal Way Addendum, the KCSPPM and the LID Manual.
Section 2. FWRC 16.25.010 is hereby amended to read as follows:
16.25.010 Core and special requirements.
Depending on the type of drainage review required, as described in FWRC 16.25.020, one or more
core or special requirements shall be met. The core and special requirements, described below, are
Ordinance No. 21-922 Page 2 of 8
also described in detail in the KCSWDM and Federal Way Addendum adopted by reference in
FWRC 16.20.010.
(1) Core requirements.
(a) Core Requirement 41— Discharge at the Natural Location. All surface and stormwater runoff
from a project must be discharged at the natural location so as not to be diverted onto or away
from downstream properties. The manner in which runoff is discharged from the project site
must not create a significant adverse impact to downhill properties or drainage systems.
(b) Core Requirement 42 — Off -Site Analysis. All proposed projects must submit an off -site
analysis report that assesses potential off -site drainage impacts associated with development of
the project site and proposes appropriate mitigations of those impacts. The initial permit
submittal shall meet the requirements outlined in the KCSWDM and the Federal Way
Addendum.
(c) Core Requirement #3 — Flow Control. All proposed projects, including redevelopment
projects, must provide on -site flow control facilities to mitigate the impacts of increased storm
and surface water runoff generated by the addition of new impervious surface, new pervious
surface and replacement impervious surfaces. These facilities shall, at a minimum, meet the
performance criteria for one of the area -specific flow control standards and be implemented
according to the applicable flow control implementation requirements described in the
KCSWDM. Flow control BMPs must be provided as directed in the KCSWDM.
(d) Core Requirement 94 — Conveyance System. All engineered conveyance system elements for
proposed projects must be analyzed, designed, and constructed to provide a minimum level of
Ordinance No. 21-922 Page 3 of 8
protection against overtopping, flooding, erosion, and structural failure as specified in the
KCSWDM.
(e) Core Requirement #S —Erosion and Sediment Control. All proposed projects that will clear,
grade, or otherwise disturb the site must provide erosion and sediment controls to prevent, to the
maximum extent possible, the transport of sediment from the project site to downstream drainage
facilities, water resources, and adjacent properties. To prevent sediment transport, erosion and
sediment control (ESC) measures that are appropriate to the project site must be applied and
performed as described in the KCSWDM. Both temporary and permanent erosion and sediment
controls shall be implemented as described in the KCSWDM.
(f) Core Requirement #6 — Maintenance and Operations. Maintenance and operation of all
drainage facilities is the responsibility of the applicant or property owner, except those facilities
for which Federal Way is granted an easement, tract, or right-of-way and officially assumes
maintenance and operation as described in the KCSWDM. Drainage facilities must be
maintained and operated in compliance with Federal Way maintenance standards.
(g) Core Requirement 97 —Financial Guarantees and Liability. All drainage facilities
constructed or modified for projects (except downspout infiltration and dispersion systems), and
any work performed in the right-of-way, must comply with the financial guarantee requirements
in FWRC Title 19
(h) Core Requirement #8 — Water Quality. All proposed projects, including redevelopment
projects, must provide water quality (WQ) facilities to treat the runoff from new and/or replaced
pollution -generating impervious surfaces and pollution -generating pervious surfaces.
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Redevelopment projects may also be required to provide WQ facilities to treat existing pollution -
generating impervious surfaces. WQ facilities shall be selected and implemented according to the
KCSWDM.'
(i) Core Requirement #9 — Flow Control BMPs. All proposed projects, including redevelopment
projects must provide onsite flow control BMPs to mitigate the impacts of storm and surface
water runoff generated by new impervious surface, new pervious surface, existing impervious
surfaces and replaced impervious surface targeted for mitigation as specified in the following
sections. Flow control BMPs must be selected and applied according to the KCSWDM.
(2) Special requirements.
(a) Special Requirement 41— Other Adopted Area -Specific Requirements. King County has
developed several types of area -specific plans and regulations that contain requirements for
drainage design. These regulations include critical drainage areas, master drainage plans, basin
plans, lake management plans, and shared facility drainage plans. In some cases, these plans and
regulations could overlap with the city of Federal Way's jurisdictional area.
The Hylebos Creek and Lower Puget Sound Basin Plan is the only one of these area -specific
regulations that currently affects Federal Way. King County developed this basin plan which
recommends specific land uses, regional capital projects, and special drainage requirements for
future development within the Hylebos and lower Puget Sound basin.
The drainage requirements of adopted area -specific regulations such as basin plans shall be
applied in addition to the drainage requirements of the KCS WDM and Federal Way Addendum
unless otherwise specified in the adopted regulation. Where conflicts occur between the two, the
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drainage requirements of the adopted area -specific regulation shall supersede those in the
KCSWDM and Federal Way Addendum.
(b) Special Requirement #2 — Floodplain/Floodway Delineation. Floodplains and floodways are
subject to inundation during extreme events. The 100-year floodplains are delineated in order to
minimize flooding impacts to new development and to prevent aggravation of existing flooding
problems by new development. Regulations and restrictions concerning development within a
100-year floodplain are found in Federal Way's environmentally sensitive areas and flood hazard
regulations.
If an approved flood hazard study exists, then it may be used as the basis for delineating the
floodplain and floodway boundaries provided the study was prepared in a manner consistent with
the KCSWDM and other Federal Way flood hazard regulations. If an approved flood
hazard study does not exist, then one shall be prepared based on the requirements described in
Chapter 4.4.2 of the KCSWDM, "Floodplain/Floodway Analysis."
(c) Special Requirement #3 — Flood Protection Facilities. Developing sites protected by levees,
revetments, or berms requires a high level of confidence in their structural integrity and
performance. Proper analysis, design, and construction is necessary to protect against the
potentially catastrophic consequences if such facilities should fail.
The applicant is required to demonstrate conformance with FEMA regulations using the methods
specified in Chapter 4.4.2 of the KCSWDM. In addition, certain easement requirements (outlined
in Chapter 4.1 of the KCSWDM) must be met in order to allow city access for maintenance of
the facility.
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(d) Special Requirement 44 — Source Control. Water quality source controls, many of which are
listed in the KCSPPM and the LID Manual, prevent rainfall and runoff water from coming into
contact with pollutants, thereby reducing the likelihood that pollutants will enter public
waterways and violate water quality standards. When applicable, structural source control
measures, such as car wash pads or dumpster area roofing, shall be shown on the site
improvement plans submitted for engineering review and approval. Other nonstructural source
control measures, such as covering storage piles with plastic or isolating areas where pollutants
are used or stored, are to be implemented after occupancy and need not be addressed during the
plan review process. All commercial and industrial projects (irrespective of size) undergoing
drainage review are required to implement applicable source controls.
(e) Special Requirement 95 — Oil Control. Projects proposing to develop or redevelop a high -use
site must provide oil controls in addition to any other water quality controls required by this
manual. Such sites typically generate high concentrations of oil due to high traffic turnover or the
frequent transfer of oil.
Section 3. Severability. Should any section, subsection, paragraph, sentence, clause, or phrase
of this ordinance, or, its application to any person or situation, be declared unconstitutional or invalid
for any reason, such decision shall not affect the validity of the remaining portions of this ordinance
or its application to any other person or situation. The City Council of the City of Federal Way
hereby declares that it would have adopted this ordinance and each section, subsection, sentence,
clauses, phrase, or portion thereof, irrespective of the fact that any one or more sections, subsections,
sentences, clauses, phrases, or portions be declared invalid or unconstitutional.
Ordinance No. 21-922 Page 7 of 8
Section 4. Corrections. The City Clerk and the codifiers of this ordinance are authorized to
make necessary corrections to this ordinance including, but not limited to, the correction of
scrivener/clerical errors, references, ordinance numbering, section/subsection numbers and any
references thereto.
Section 5. Ratification. Any act consistent with the authority and prior to the effective date of
this ordinance is hereby ratified and affirmed.
Section 6. Effective Date. This ordinance shall take effect and be in force thirty (30) days
from and after its passage and publication, as provided by law.
PASSED by the City Council of the City of Federal Way this 16th day of November, 2021
CITY OF FEDERAL WAY:
'JIM-TERFILL, MAYOR
ATTEST: v`
ST P ANIE COURTNEY, CM TY CLERK
APPROVED AS TO FORM:
—8-izclee-
J. RYAN CALL, CITY ATTORNEY
FILED WITH THE CITY CLERK: 10/27/2021
PASSED BY THE CITY COUNCIL: 11/16/2021
PUBLISHED: 11/19/2021
EFFECTIVE DATE: 12/12/2021
ORDINANCE NO.: 21-922
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