HomeMy WebLinkAboutO-3035 - Related to low impact development stormwater mgt regCITY OF MARYSVILLE
Marysville, Washington
ORDINANCE '3 0 3j
AN ORDINANCE OF THE CITY OF MARYSVILLE, WASHINGTON,
UPDATING THE LOW IMPACT DEVELOPMENT STORMWATER
MANAGEMENT REGULATIONS PURSUANT TO THE WESTERN
WASHING TON NPDES PHASE II MUNICIPAL STORMW ATER PERMIT
ISSUED TO THE CITY BY THE WASHINGTON STATE DEPARTMENT
OF ECOLOGY AND AMENDING CHAPTERS 12.02A, 14.03, 14.15, 14.16,
14.17, 14.21, 22A.020, 22C.120, AND 22C.130, AMENDING SECTION
22A.010.160, AND REPEALING CHAPTER 22C.260 OF THE
MARYSVILLE MUNICIPAL CODE.
WHEREAS, the Federal Clean Water Act, 33 U.S.C. 1251 et seq. (the Act), requires
certain local governments such as the City of Marysville to implement storm water management
programs and regulations within prescribed time frames, and pursuant to said Act the United
States Environmental Protection Agency (EPA) has adopted rules for such stormwater programs
and regulations; and
WHEREAS, the EPA has delegated authority to the Washington State Department of
Ecology (Ecology) to administer such stormwater programs and regulations, and Ecology has
issued the Western Washington Phase II Municipal Stormwater Permit, effective August 1, 2013
through July 31, 2018, which requires local governments such as the City of Marysville to
implement numerous stormwater management requirements, including adopting Ecology's 2012
Stormwater Management Manual for Western Washington, making Low Impact Development
the preferred and commonly used approach to site development by December 31, 2016, and
updating illegal discharge and connection regulations by February 2, 2018; and
WHEREAS, in 1999, the City Council adopted Ordinance 2245, which established a
stormwater utility to be responsible for the operation, construction and maintenance of
stormwater facilities, as set forth in Ch. 14.19 MMC; and
WHEREAS, in 2010, the City Council adopted Ordinance 2816, which adopted
Ecology's 2005 Stormwater Management Manual for Western Washington and related
regulations, as set forth in Ch. 14.15 MMC; and
WHEREAS, in 2009, the City Council adopted Ordinance 2782, which adopted illegal
discharge and connection regulations; and
WHEREAS, in order to comply with the currently effective Western Washington Phase
II Municipal Stormwater Permit, the City has prepared this ordinance amending and updating the
City's current stormwater regulations and related municipal code provisions, as primarily set
forth in Title 14 MMC, to implement Low Impact Development; and
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WHEREAS, the State Growth Management Act, RCW Chapter 36.70A mandates that
cities periodically review and amend development regulations which include but are not limited
to zoning ordinances and official controls; and
WHEREAS, RCW 36.70A.106 requires the processing amendments to the City's
development regulations in the same manner as the original adoption of the City's
comprehensive plan and development regulations; and
WHEREAS, the State Growth Management Act requires notice and broad public
participation when adopting or amending the City's comprehensive plan and development
regulations; and
WHEREAS, the City, in reviewing and amending its development regulations has
complied with the notice, public participation, and processing requirements established by the
Growth Management Act, as more fully described below; and
WHEREAS, the City Council of the City of Marysville finds that from time to time it is
necessary and appropriate to review and revise provisions of the City's municipal code and
development code (MMC Title 22); and
WHEREAS, the development code amendment is consistent with the following required
findings of MMC 22G.010.500:
(1) The amendment is consistent with the purposes of the comprehensive plan;
(2) The amendment is consistent with the purpose of this title;
(3) There have been significant changes in the circumstances to warrant a change;
( 4) The benefit or cost to the public health, safety and welfare is sufficient to warrant the
action.
WHEREAS, the Planning Commission discussed the above-referenced amendments to
MMC Title 22 during a public meeting held on September 13, 2016; and
WHEREAS, on September 27, 2016 the Marysville Planning Commission held a duly-
advertised public hearing; and
WHEREAS, on September 27, 2016, the Marysville Planning Commission
recommended that the City Council adopt the proposed amendments to MMC Title 22; and
WHEREAS, at a public meeting on October 10, 2016, the Marysville City Council
reviewed and considered the Marysville Planning Commission's Recommendation and proposed
amendments to MMC Title 22, as well as the above referenced amendments to the MMC; and
WHEREAS, the City of Marysville has submitted the proposed development regulation
revisions to the Washington State Department of Commerce on September 1, 2016, seeking
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expedited review under RCW 36.70A.160(3)(b) in compliance with the procedural requirement
under RCW 36.70A.106; and
WHEREAS, on September 1, 2016, the City's SEPA Responsible Official complied with
the State Environmental Policy Act (SEPA) by issuing a Determination of Nonsignificance
(DNS) for the adoption of this ordinance and by complying with SEPA's procedural
requirements for issuing the DNS; and
WHEREAS, the City Council has determined that it is in the public interest and in
furtherance of the public health and welfare to adopt this ordinance;
NOW THEREFORE, the City Council of the City of Marysville, Washington do ordain
as follows:
Section 1. Amendment of Municipal Code. Chapter 12.02A of the Marysville
Municipal Code, specifically sections 12.02A.090 and 12.02A.100 are hereby amended to read
as set forth in Exhibit A, which is attached hereto and incorporated herein by this reference.
Section 2. Amendment of Municipal Code. Chapter 14.03 of the Marysville
Municipal Code, specifically sections 14.03.030, 14.03.300, and 14.03.330 are hereby amended
to read as set forth in Exhibit B, which is attached hereto and incorporated herein by this
reference.
Section 3. Amendment of Municipal Code. Chapter 14.15 of the Marysville
Municipal Code, specifically sections 14.15.015, 14.15 .020, 14.15.030, 14.15.040, 14.15.050,
14.15.062, 14.15.065, 14.15.120, 14.15.130, and 14.15.140, are hereby amended and a new
section 14 .15 .15 5 is added, all to read as set forth in Exhibit C, which is attached hereto and
incorporated herein by this reference.
Section 4. Amendment of Municipal Code. Chapter 14.16 of the Marysville
Municipal Code, specifically section 14.16.040, is hereby amended to read as set forth in Exhibit
D, which is attached hereto and incorporated herein by this reference.
Section 5. Amendment of Municipal Code. Chapter 14.17 of the Marysville
Municipal Code, specifically section 14.17.035, is hereby amended to read as set forth in Exhibit
E, which is attached hereto and incorporated herein by this reference.
Section 6. Amendment of Municipal Code. Chapter 14.21 of the Marysville
Municipal Code, specifically sections 14.21.030, 14.21.050, and 14.21.060, are hereby amended
to read as set forth in Exhibit F, which is attached hereto and incorporated herein by this
reference.
Section 7. Amendment of Municipal Code. Chapter 22A.020 of the Marysville
Municipal Code, specifically section 22A.020.170, is hereby amended to read as set forth in
Exhibit G, which is attached hereto and incorporated herein by this reference.
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Section 8. Amendment of Municipal Code. Chapter 22C.120 of the Marysville
Municipal Code, specifically section 22C.120.170, is hereby amended to read as set forth in
Exhibit H, which is attached hereto and incorporated herein by this reference.
Section 9. Amendment of Municipal Code. Chapter 22C.130 of the Marysville
Municipal Code, specifically section 22C.130.050, is hereby amended to read as set forth in
Exhibit I, which is attached hereto and incorporated herein by this reference.
Section 10. Amendment of Municipal Code. Section 22A.010.160 of the Marysville
Municipal Code, entitled "Amendments," is hereby amended as follows by adding reference to
this adopted ordinance in order to track amendments to the City's Unified Development Code (all
unchanged provisions of MMC 22A.010.160 remain unchanged and in effect):
"22A.010.160 Amendments.
The following amendments have been made to the UDC subsequent to its adoption:
Ordinance Title (description)
30?:; 5 Low Impact Development Update
Effective Date "2 l peu~.VY\ tit.~ -::>
f.Jc.f o bot; JO, 2016"
Section 11. Repeal. Chapter 22C.260 of the Marysville Municipal Code is hereby
repealed in its entirety.
Section 12. Severabilitv. If any section, subsection, sentence, clause, phrase or word
of this ordinance should be held to be invalid or unconstitutional by a court of competent
jurisdiction, such invalidity or unconstitutionality thereof shall not affect the validity or
constitutionality of any other section, subsection, sentence, clause, phrase or word of this
ordinance.
Section 13. Effective date. This ordinance shall take effect on December 31, 2016.
PASSED by the City Council and APPROVED by the Mayor this j{J_ day of Qcf c/,t;l., 2016.
CITY OF MARYSVILLE
By
ATTEST:
By
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Approved as to form:
By
Date of Publication:
Effective Date: 12/31/16
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Exhibit A – Chapter 12.02A
1
12.02A.090 Frontage improvements required.
(1) The term “frontage improvements” as used in this section shall refer to the construction, reconstruction or repair of
the following facilities along the full abutting public street frontage of property being developed:
(a) Curbs, gutters and sidewalks;
(b) Underground Sstorm drainage facilities including LID facilities and/or underground facilities;
(c) Patching the street from its preexisting edge to the new curb line;
(d) Overlayment of the existing public street to its centerline;
(e) Construction of new streets within dedicated, unopened right-of-way.
All such frontage improvements shall be constructed to city specifications.
(2) Property owners shall be required to construct frontage improvements along the full abutting public street frontage
of property which is developed as provided in subsection (3) of this section; provided, that overlayment of an existing
public street to its centerline shall not be required for single-family or duplex development.
(3) Frontage improvements shall be constructed as follows:
(a) Formal plats: frontage improvements shall be completed prior to recording the final plat, or may be
bonded pursuant to provisions of Chapter 22G.090 MMC;
(b) Short plats: frontage improvements shall be completed for frontage abutting all lots prior to the
issuance of a building permit for any lot in the short plat;
(c) Construction of a multi-family dwelling unit, business, commercial or industrial building: frontage
improvements shall be completed prior to occupancy of the building;
(d) Construction of a single-family or duplex dwelling unit: frontage improvements shall be completed
prior to occupancy of the structure, provided the following exceptions apply:
(i) An existing lot in an existing single-family subdivision, short plat, or binding site plan where the
lots are fully developed and frontage improvements were constructed to the standard in effect at
the time of final plat recording; or
Exhibit A ‐ 2 2
(ii) An existing lot (greater than one acre) where there are no frontage improvements meeting city
standards constructed within 200 feet of the lot or identified through approved plats, and
development potential exists for future development. At the discretion of the director, frontage
improvements may be reduced or deferred until the entire parcel is developed.
(iii) Replacement of an existing single-family or duplex unit where there are no frontage
improvements constructed within 200 feet of the lot. Frontage improvements may be waived,
providing construction of the new dwelling unit is completed within 12 months of the demolition of
the existing unit.
(e) The granting of an exception to construct frontage improvements as outlined in subsection (3)(d) of
this section does not waive the property owner’s requirement to dedicate right-of-way as established in
MMC 12.02A.110;
(f) Construction of any additions, alterations or repairs to a residential building that result in an increase
in the number of dwelling units as defined in Chapter 22A.020 MMC, or to a business, commercial or
industrial building that result in an increase in pedestrian or vehicular traffic, within any 12-month
period: frontage improvements shall be completed prior to occupancy;
(g) Development of a mobile home park or other project requiring a binding site plan: frontage
improvements shall be completed prior to occupancy;
(h) Any change in the occupancy classification of an existing building or structure on the property that
results in an increase in pedestrian and/or vehicular traffic within any 12-month period. Frontage
improvements shall be completed prior to occupancy.
(4) The director of community development or designee shall have authority to grant administrative variances from
any of the requirements of this section pursuant to MMC 12.02A.120. Such variances shall be conditioned upon the
property owner signing a contract providing for the construction of the frontage improvements at a future time. Said
contract shall include, but not be limited to, the making of a cash deposit with the city in an amount equal to the
estimate of the city engineer of the cost of said improvements, including design cost, plus an administrative overhead
fee of 15 percent. No other form of payment or security shall be authorized. In the event the frontage improvements
are not constructed by the property owner within five years of the grant of a variance, the cash deposit shall be
forfeited to the city. If said frontage improvements are constructed by the property owner at the request of the city
within five years of the grant of a variance, said cash deposit shall be refunded to the property owner less the 15
percent overhead fee. Said contract shall be subject to the approval of the city attorney and shall contain such other
Exhibit A ‐ 3 3
provisions as are necessary to effectuate the future construction of such frontage improvements. The refusal of a
property owner to enter into such agreement or to post a cash amount as specified herein shall be a basis to deny a
variance request and shall require the construction of such frontage improvements in accordance with subsections (1)
through (4) of this section.
The council authorizes the mayor to review, execute and sign contracts for deferred construction of curbs, gutters and
sidewalks pursuant to this chapter.
Any party aggrieved by a decision of the director of community development or city engineer may appeal the decision
pursuant to MMC 12.02A.120(4).
12.02A.100 Minimum access requirements.
No development permits or short plats shall be issued or approved by the city for any lot, parcel or tract which does
not comply with the following minimum access requirements:
(1) The front-yard line or a side-yard line must abut immediately upon and provide direct access to one of the
following:
(a) An open, constructed and maintained public road; or
(b) A private road in an approved formal plat.
(2) If one or more lots are built upon a unit of property under one ownership, they shall, for the purpose of this title, be
considered as a single lot; provided, that internal private access roads or driveways serving two or more dwelling units
located on a single lot shall not exceed 600 feet in length, and shall have a minimum right-of-way width of 205 feet.
(3) Each and every lot having access to a private road shall have responsibility for maintenance of such private road
and associated storm water drainage facilities unless specifically designated for maintenance by the city.
(4) Any private roads esta---blished under this section shall contain a utilities easement approved by the city.
Exhibit B – Chapter 14.03
4
14.03.030 Location of utility lines – Easements.
(1) All public utility lines shall be installed in public streets or alleys or in easements which have been granted to and
accepted by the city for such purposes.
(2) Utility easements granted to the city shall be not less than 10 feet in width; provided, that when such easements
extend from the end of an existing public road, or extend along the alignment of any anticipated future public road,
such easement shall be not less than 20 feet in width. Pipes shall be installed a minimum of 5 feet from edge of
easement.
(3) All stormwater treatment and flow control facilities permitted per the requirements in Chapter 14.15 shall record
access easements allowing the City Engineer, or designee, to conduct facility inspections. The easement shall be in a
form acceptable to the City Attorney and may be recorded by itself or included in a plat, short plat or covenant.
14.03.300 Connections required – Storm drainage system.
(1) The owner of any property which is not connected to the public storm drainage system shall be required to extend
any storm drainage line main which is within 200 feet of the property, and to connect to and use the same, or install
an acceptable overflow for stormwater treatment and flow control BMPs/facilities that infiltrate, for all developed
portions of the property, under any of the following circumstances:
(a) As a condition of final approval of a subdivision;
(b) As a condition of final approval of a short subdivision;
(c) As a condition of final approval of a binding site plan for any mobile home park, condominium, planned unit
development, industrial park or shopping center;
(d) As a condition of any building, grading, paving or other development approval, including rezones or
conditional use permits, which will have a significant adverse impact upon storm drainage, as determined by
the public works director or designee.
(2) The public works director or designee may waive the requirement of subsection (1) of this section on the following
grounds:
(a) If the public works director or designee finds that the capacity or condition of the existing public storm
drainage system is insufficient or inadequate to serve the subject property; or
Exhibit B ‐ 5
(b) If the public works director or designee finds that it would cause a practical difficulty to require the
connection of the subject property to the public storm drainage system by reason of circumstances which are
unique to the property and not generally shared by other properties in the vicinity; or
(c) If the public works director or designee finds that proposed on-site storm water BMPs are adequate under
the requirements of this title.
No such waiver shall be granted which would be detrimental to the public health, safety, welfare or environment, or
which would be inconsistent with the long-range plans for the public storm drainage system. In all cases where a
waiver is granted, the property owner shall be required to strictly comply with storm water retention/detention
requirements of Chapter 14.15 MMC.
The decision of the public works director or designee regarding such waivers shall be final, subject to appeal to the
city council; provided, that in cases where a property owner has applied for development approval which is to be ruled
upon by the city council itself, waivers referred to herein shall be determined by the city council after taking into
consideration the recommendation of the city engineer.
14.03.330 Inspection fees – Storm drainage system.
All connections to the public storm drainage systems permitted under the provisions of MMC 14.15 shall be inspected
by the city engineer or designee. In the event that a storm drainage line is to be deeded to and accepted by the city,
the party constructing the same shall pay the city an inspection fee per Chapter 14.07 MMC. No line or facility shall be
accepted by the city until all inspection fees have been paid and until the city engineer or designee certifies that the
same has been constructed in accordance with city specifications.
Exhibit C – Chapter 14.15
6
14.15.015 Stormwater management manual adopted.
The 2005 State Department of Ecology 2012 Stormw Water Management Manual for Western Washington, as
amended in December 2014 and as amended by this code, is hereby adopted as the city’s minimum storm water
regulations, and as a technical reference manual and maintenance standard and is hereinafter referred to as the
“Stormwater Manual.” Stormwater infrastructure shall also be designed and constructed in accordance with the City’s
Engineering Design and Development Standards (EDDS).
14.15.020 Definitions.
For the purpose of this chapter and other provisions in this title related to storm water, certain terms, phrases, words
and their derivatives shall be defined and construed as specified in the Stormwater Manual and in this title. Words
used in the singular include the plural, and the plural the singular. The words “shall,” “will,” and “must” are mandatory;
the words “should” and “may” are permissive. When any definition in this title conflicts with definitions in the
Stormwater Manual or any other ordinance of the city, that which provides more environmental protection shall apply
unless specifically provided otherwise in this title.
(1) “Applicant” means any person who has applied for a development permit or approval.
(2) “Certified Erosion and Sediment Control Lead (CESCL)” means an individual who has current certification through
an approved erosion and sediment control training program that meets the minimum training standards established by
the Department of Ecology (see BMP C160 in the Stormwater Manual). A CESCL is knowledgeable in the principles
and practices of erosion and sediment control. The CESCL must have the skills to assess site conditions and
construction activities that could impact the quality of storm water and the effectiveness of erosion and sediment
control measures used to control the quality of storm water discharges.
(3) “City planner” also means community development director or his/her designee.
(4) “Comprehensive drainage plan” means a detailed analysis adopted by the city which compares the capabilities
and needs for runoff accommodation due to various combinations of development, land use, structural and
nonstructural management alternatives. The plan recommends the form, location, and extent of quantity and quality
control measures which would satisfy legal constraints, water quality standards and community standards and
identifies the institutional and funding requirements for plan implementation.
(5) “Conveyance system” means the drainage facilities, both natural and manmade, which collect, contain, and
provide for the flow of surface and storm water from the highest points on the land down to a receiving water. The
natural elements of the conveyance system include swales and small drainage courses, streams, rivers, lakes, and
Exhibit C ‐ 7
wetlands. The human-made elements of the conveyance system include gutters, ditches, pipes, channels, and most
retention/detention facilities.
(6) “Department” means the public works or community development department of the city of Marysville, as
appropriate for capital or private development projects.
(7) “Developer” means the person(s) applying for permits or approvals, whether an individual(s) or corporation(s) or
governmental agency(ies) applying for permits or approvals.
(8) “Director of public works” or “director” means the director of the public works department or his/her designee.
“(9) Discharge Storm Wwater Directly or Indirectly to the Marysville Small Municipal Separate Storm Sewer System
(MS4).” means that A project discharges storm water directly or indirectly to the MS4 if:
(a) The drainage system installed is in right-of-way or an area that will become right-of-way after
construction and final site approval;
(b) The drainage system installed will become publicly owned after construction and final site approval;
(c) The drainage system installed is intended to overflow to a portion of the existing MS4 or public
right-of-way; or
(d) The drainage system installed is intended to outfall into a portion of the existing MS4 or public right-
of-way.
(10) “Drainage system” or “storm drainage system” or “storm water system” means the same as the Stormwater
Manual definition for “storm water drainage system.”
(11) “Engineer” means the city engineer or development services manager, as designated for enforcement of capital
or private development activities, of Marysville.
(12) “Existing grade” means the grade prior to grading.
(13) “Finish grade” means the final grade of the site, which conforms to the approved plan.
(14) “Grading” or “grading activity” means any excavating, filling, grubbing or grading or combination thereof.
(15) “Ground water” means water in a saturated zone or stratum beneath the surface of land or a surface water body.
Exhibit C ‐ 8
(16) “Municipal separate storm sewer system (MS4)” means a conveyance, or system of conveyances (including
roads with drainage systems, municipal streets, catch basins, curbs, gutters, ditches, manmade channels, or storm
drains):
(a) Owned or operated by a state, city, town, borough, county, parish, district, association, or
other public body (created by or pursuant to state law) having jurisdiction over disposal of
wastes, storm water, or other wastes, including special districts under state law such as a
sewer district, flood control district or drainage district, or similar entity, or an Indian tribe or an
authorized Indian tribal organization, or a designated and approved management agency
under Section 208 of the CWA that discharges to waters of the United States;
(b) Designed or used for collecting or conveying storm water;
(c) Which is not a combined sewer; and
(d) Which is not part of a publicly owned treatment works (POTW) as defined in the Code of
Federal Regulations at 40 CFR 122.2; and.
(e) Which is defined as “large” or “medium” or “small” or otherwise designated by Ecology
pursuant to 40 CFR 122.26.
(17) “Parcel” means a tract or plot of land of any size, which may or may not be subdivided or improved.
(18) “Planned residential developments” refers to residential developments which are planned and/or developed in
several stages but submitted together for approvals, and which typically consist of clusters of structures interspersed
with areas of common open spaces (refer to Chapter 22G.080 MMC).
(19) “Private drainage system” or “private storm water disposal systems” means drainage systems located on private
property that may or may not discharge directly as through pipes, channels, etc., or indirectly as sheet flow,
subsurface flow, etc., into the city’s drainage system.
(20) “Public storm drainage system” means that portion of the drainage system of the city located on public right-of-
way, easements or other property owned by the city. Public storm drainage system does not include [Llow impact
development BMP’s such as bioswales, infiltration ponds, pervious pavement, and other associated low impact
development infrastructure] located within easements held by the City of Marysville for inspection purposes only.
(21) “Rough grade” means the stage at which the grade approximately conforms to the approved plan.
Exhibit C ‐ 9
(22) “Site plan” means a plan which indicates the character of the existing site, topography, natural drainage features
on or adjacent to the site, the location and dimensions of all impervious surfaces, flow arrows indicating the direction
of storm water flows on-site and any off-site flows entering the site, and the proposed method of utilizing the existing
drainage system.
(23) “Small municipal separate storm sewer system” or “small MS4” means an MS4 that is not defined as “large” or
“medium” pursuant to 40 CFR 122.26(b)(4) & (7) or designated under 40 CFR 122.26 (a)(1)(v).
a conveyance or system of conveyances including roads with drainage systems, municipal streets, catch basins,
curbs, gutters, ditches, manmade channels and/or storm drains which is:
(a) Owned or operated by a city, town, county, district, association or other public body created pursuant to state law
having jurisdiction over disposal of sewage, industrial wastes, storm water, or other wastes, including special districts
under state law such as a sewer district, flood control district or drainage district, or similar entity.
(b) Designed or used for collecting or conveying storm water.
(c) Not a combined sewer system.
(d) Not part of a publicly owned treatment works (POTW) as defined at 40 CFR CFR.
(e) Not defined as “large” or “medium” pursuant to 40 CFR CFR(b)(4) and (7) or designated under 40 CFR
CFR(a)(1)(v).
Small MS4s include systems similar to separate storm sewer systems in municipalities such as: universities, large
publicly owned hospitals, prison complexes, highways and other thoroughfares.
Small MS4s do not include storm drain systems operated by nongovernmental entities such as: individual buildings,
private schools, private colleges, private universities, and industrial and commercial entities.
(24) “Storm water site plan” means the comprehensive report containing all of the technical information and analysis
necessary to evaluate a proposed new development or redevelopment project for compliance with storm water
requirements. Contents of the storm water site plan will vary with the type and size of the project, and individual site
characteristics. See the Stormwater Manual for details.
(25) “Subject property” means the tract of land which is the subject of the permit and/or approval action.
Exhibit C ‐ 10
(26) “Undeveloped conditions” means the state, status, or condition of the subject property prior to any development
of the property that has occurred, which may include trees, pastures, meadows, or native features.
14.15.030 Applicability.
(1) Storm water management review and approval by the city is required when any new development, redevelopment,
or proposed construction site project meets or exceeds the threshold conditions defined in MMC 14.15.040 (e.g., new
impervious area, drainage system modifications, redevelopments, etc.) and/or is subject to a city development permit
or approval requirement. All the provisions of this title are applicable to any project requiring storm water management
review and approval.
(2) Commencement of construction work under any of the nonexempt actions, permits, or applications shall not begin
until the department approves a storm water pollution prevention plan (SWPPP) pursuant to the requirements of MMC
14.15.050.
(3) Whenever a minimum area or quantity requirement is set forth in this chapter, such requirement shall be met if any
activity or development occurs on the subject property within a continuous 18-month period.
(4) Unless otherwise specified in this chapter, all standards, definitions, and requirements shall be in accordance with
the Stormwater Manual.
(5) The following activities are exempt from the minimum requirements set forth in MMC 14.15.050: even if such
practices meet the definition of new development or redevelopment.
(a) Forest Practices. Forest practices regulated under WAC Title 222, except for Class IV General
forest practices that are conversions from timberland to other uses, are exempt from the provisions of
the minimum requirements.
(b) Commercial Agriculture. Commercial agriculture practices involving working the land for production
are generally exempt. However, the conversion from timberland to agriculture and the construction of
impervious surfaces are not exempt.
(c) Oil and Gas Field Activities or Operations. Construction of drilling sites, waste management pits,
and access roads, as well as construction of transportation and treatment infrastructure such as
pipelines, natural gas treatment plants, natural gas pipeline compressor stations, and crude oil
pumping stations are exempt. Operators are encouraged to implement and maintain best management
practices to minimize erosion and control sediment during and after construction activities to help
ensure protection of surface water quality during storm events.
Exhibit C ‐ 11
(d) Pavement Maintenance.Road Maintenance.
(i) The following pavement maintenance road maintenance practices are exempt: pothole and
square cut patching, overlaying existing asphalt or concrete pavement with asphalt or concrete
without expanding the area of coverage, shoulder grading, reshaping/regrading drainage
systems, crack sealing, resurfacing with in-kind material without expanding the road prism, and
vegetation maintenance.
(ii) The following pavement maintenance road maintenance practices are considered
redevelopment, and therefore are not categorically exempt. The extent to which the minimum
requirements in MMC 14.15.050 apply is explained for each circumstance.
(A) Removing and replacing a paved surface to base course or lower, or repairing the
roadway base:. If impervious surfaces are not expanded, MMC 14.15.050 minimum
requirements Nos. (1) through (5) apply.
However, in most cases, only MMC 14.15.050 minimum requirement No. (2), Construction
Storm Water Pollution Prevention Plan (SWPPP), will be germane. Where appropriate,
project proponents are encouraged to look for opportunities to use permeable and porous
pavements.
(B) Extending the pavement edge without increasing the size of the road prism, or paving
graveled shoulders: These are considered new impervious surfaces and are subject to the
minimum requirements in MMC 14.15.050 that are triggered when the thresholds identified
for redevelopment projects are met.
(C) Resurfacing by upgrading from dirt to gravel, asphalt, or concrete; upgrading from
gravel to asphalt, or concrete; or upgrading from a bituminous surface treatment (“chip
seal”) to asphalt or concrete: These are considered new impervious surfaces and are
subject to the minimum requirements in MMC 14.15.050 that are triggered when the
thresholds identified for redevelopment projects are met.
(e) Underground Utility Projects. Underground utility projects that replace the ground surface with in-
kind material or materials with similar runoff characteristics are only subject to MMC 14.15.050(2),
Minimum Requirement No. 2, Construction Stormw Water Pollution Prevention Plan (SWPPP).
Exhibit C ‐ 12
14.15.040 Minimum requirement thresholds.
Not all of the minimum requirements in MMC 14.15.050 apply to every development or redevelopment project. The
applicability varies depending on the type and size of the project. This section identifies thresholds that determine the
applicability of the minimum requirements in MMC 14.15.050 to different projects. The flow charts in Figures
14.15.040(1) and 14.15.040(2) must be used to determine which of the minimum requirements in MMC 14.15.050
apply. The minimum requirements themselves are presented in MMC 14.15.050.
Exhibit C ‐ 13
Minimum Requirements
#1 through #5 apply
to the new and
replaced hard
surfaces and the land
disturbed.
All Minimum
Requirements apply
to the new and
replaced hard
surfaces and
converted vegetation
areas.
Minimum
Requirement
#2 applies.
Figure 14.15.040(1) Flow Chart for Determining Requirements for New Development
Start Here
Does the site have
35% or more of
existing impervious
coverage?
No
See Redevelopment
Minimum
Requirements and
Flow Chart Figure
14.15.040(2)
Does the project
result in 5,000
square feet, or
greater, of new
plus replaced hard
surface area?
No
Does the project convert
¾ acres or more of
vegetation to lawn or
landscaped areas, or
convert 2.5 acres or more
of native vegetation to
pasture?
No Does the project
result in 2,000 square
feet, or greater, of
new plus replaced
hard surface area?
No
Does the project have
land disturbing
activities of 7,000
square feet or greater?
Yes
No
Exhibit C ‐ 14
Exhibit C ‐ 15
Exhibit C ‐ 16
Does the project result in 2,000 square feet, or more, of new plus replaced hard
surface area?
OR
Does the land disturbing activity total 7,000 square feet or greater?
Yes No
Minimum Requirements #1 through #5
apply to the new and replaced hard
surfaces and the land disturbed.
Minimum Requirements #2 applies.
Next Question
Does the project add 5,000 square feet or more of new hard surfaces?
OR
Convert ¾ acres or more of vegetation to lawn or landscaped areas?
OR
Convert 2.5 acres or more of native vegetation to pasture?
Yes
All Minimum Requirements apply to
the new hard surfaces and the
converted vegetation areas.
Next
Question
Yes
No
Is this a road
related project?
No
Does the project add 5,000 square feet or more of new hard surfaces?
Yes No
Do new hard surfaces add 50%
or more to the existing hard
surfaces within the project
limits?
No Yes
Is the total of new plus replaced hard surfaces
5,000 square feet or more, AND does the
value of the proposed improvements –
including interior improvements – exceed 50%
of the assessed value (or replacement value)
of the existing site improvements?
Yes No No additional
requirements
All Minimum Requirements apply to
the new and replaced hard surfaces
and converted vegetation areas.
No additional
requirements
Figure 14.15.040(2) Flow Chart for Determining Requirements for Redevelopment
Exhibit C ‐ 17
(1) New Development. All new development shall be required to comply with MMC 14.15.050(2), Minimum
Requirement No. 2.
(a) The following new development shall comply with MMC 14.15.050 minimum requirements
Nos. 1 through 5 for the new and replaced hardimpervious surfaces and the land disturbed:
(i) Results in Creates or adds 2,000 square feet, or greater, of new, replaced, or new plus
replaced hardimpervious surface area; or
(ii) Has land disturbing activity of 7,000 square feet or greater.
(b) The following new development shall comply with MMC 14.15.050 minimum requirements
Nos. 1 through 9 for the new and replaced impervioushard surfaces and the converted pervious
surfacesvegetation areas:
(i) Creates or adds 5,000 square feet, or greater more, of new plus replacedimpervious
hard surface area; or
(ii) Converts three-quarters acres, or more, of native vegetation to lawn or landscaped
areas; or
(iii) Converts 2.5 acres, or more, of native vegetation to pasture.
(2) Redevelopment. All redevelopment shall be required to comply with MMC 14.15.050(2), minimum
requirement No. 2. In addition, all redevelopment that exceeds certain thresholds shall be required to comply
with additional minimum requirements in MMC 14.15.050 as follows.
(a) The following redevelopment shall comply with MMC 14.15.050, minimum requirements
Nos. 1 through 5 for the new and replaced hardimpervious surfaces and the land disturbed:
(i) The new, replaced, or total of new plus replaced impervious surfaces isResults in 2,000
square feet or more,; or of new plus replaced hard surface area, or
(ii) Has land disturbing activity of 7,000 square feet or greater.Seven thousand square feet
or more of land disturbing activities.
(b) The following redevelopment shall comply with MMC 14.15.050 minimum requirements Nos.
1 through 9 for the new impervioushard surfaces and converted perviousvegetation areas:
Exhibit C ‐ 18
(i) Adds 5,000 square feet or more of new impervioushard surfaces; or
(ii) Converts three-quarters acres, or more, of native vegetation to lawn or landscaped
areas; or
(iii) Converts 2.5 acres, or more, of native vegetation to pasture.
(c) If the runoff from the new impervious surfaces and converted pervious surfaces is not
separated from runoff from other surfaces on the project site, the storm water treatment facilities
must be sized for the entire flow that is directed to them.
(d) The director may allow the minimum requirements in MMC 14.15.050 to be met for an
equivalent (flow and pollution characteristics) area within the same site. For public roads
projects, the equivalent area does not have to be within the project limits, but must drain to the
same receiving water.
(3) Additional Requirements for Redevelopment Project Sites.
(a) For road-related projects, runoff from the replaced and new impervioushard surfaces
(including pavement, shoulders, curbs, and sidewalks) and the converted vegetation areas shall
meet all the minimum requirements in MMC 14.15.050 if the new impervioushard surfaces total
5,000 square feet or more and total 50 percent or more of the existing impervioushard surfaces
within the project limits. The project limits shall be defined by the length of the project and the
width of the right-of-way.
(b) Other types of redevelopment projects shall comply with all the minimum requirements in
MMC 14.15.050 for the new and replaced impervioushard surfaces and the converted
vegetation areas if the total of new plus replaced impervioushard surfaces is 5,000 square feet
or more, and the valuation of proposed improvements – including interior improvements –
exceeds 50 percent of the assessed value of the existing site improvements.
(c) The director may exempt or institute a stop-loss provision for redevelopment projects from
compliance with minimum requirements MMC 14.15.050 Minimum Requirements No.5 On-site
Stormwater Management, No.6 Runoff Treatment, No.7 Flow Control and/or No.8 Wetlands
Protection as applied to the replaced hard surfaces if the director has adopted a plan and a
schedule that fulfills those requirements in regional facilities. for treatment, flow control, and
Exhibit C ‐ 19
wetlands protection as applied to the replaced impervious surfaces if the director has adopted a
plan and a schedule that fulfills those requirements in regional facilities. See also MMC
14.15.175 and 14.15.180 and Chapter 14.18 MMC.
(d) The director may grant a variance/exception to the application of the flow control
requirements to replaced impervious surfaces if such application imposes a severe economic
hardship. See MMC 14.15.175 and 14.15.180.
14.15.050 Minimum requirements.
This section describes the thresholds of the minimum requirements for storm water management at new
development and redevelopment sites. MMC 14.15.040 should be consulted to determine which of the
minimum requirements below apply to any given project. Figures 14.15.040(1) and 14.15.040(2) should be
consulted to determine whether the minimum requirements apply to new surfaces, replaced surfaces or new
and replaced surfaces. See the Stormwater Manual for more information about each of the Minimum
Requirements.
(1) Minimum Requirement No. 1: Preparation of Storm Water Site Plans. All projects meeting the thresholds in
MMC 14.15.040 shall submit a storm water site plan. Storm water site plans shall be prepared in accordance
with Chapter 3 of Volume I of the Stormwater Manual.
(2) Minimum Requirement No. 2: Construction Storm Water Pollution Prevention Plan (SWPPP).
(a) The city may choose to allow compliance with this minimum requirement to be achieved for an individual
site if the site is covered under Ecology’s General NPDES Permit for Storm Water Discharges Associated with
Construction Activities and fully implementing the requirements of that permit.
(b) The city may choose to allow site operators to apply an “erosivity waiver” to projects disturbing less than five
acres that meet the requirements in subsection (2)(j) of this section; such projects would be waived from the
requirement that the city review site plans for construction phase storm water pollution prevention.
(c) The city may develop an abbreviated SWPPP format to meet the SWPPP requirement under the NPDES
Phase II Municipal Storm Water Permit for sites that are less than 5,000 square feet of new impervious surface;
or new, replaced, or new plus replaced is less than 2,000 square feet.
(d) All new development and redevelopment projects are responsible for preventing erosion and discharge of
sediment and other pollutants into receiving waters. All projects must submit a construction storm water
pollution prevention plan (SWPPP) as part of the storm water site plan (see subsection (1) of this section,
Exhibit C ‐ 20
Minimum Requirement No. 1: Preparation of Storm Water Site Plans) for all projects which meet the thresholds
in MMC 14.15.040. The SWPPP shall be implemented beginning with initial soil disturbance and until final
stabilization.
(e) Sediment and erosion control BMPs shall be consistent with the BMPs contained in Chapters 3 and 4 of
Volume II of the Stormwater Manual, and/or other equivalent BMPs contained in technical storm water manuals
approved by the Department of Ecology.
(f) The SWPPP shall include a narrative and drawings. All BMPs shall be clearly referenced in the narrative and
marked on the drawings. The SWPPP narrative shall include documentation to explain and justify the pollution
prevention decisions made for the project. Clearing and grading activities for developments shall be permitted
only if conducted pursuant to an approved site development plan (e.g., subdivision approval) that establishes
permitted areas of clearing, grading, cutting, and filling. When establishing these permitted clearing and grading
areas, consideration should be given to minimizing removal of existing trees and minimizing
disturbance/compaction of native soils except as needed for building purposes. These permitted clearing and
grading areas and any other areas required to preserve critical or sensitive areas, buffers, native growth
protection easements, or tree retention areas as may be required by Chapter 22E.010 MMC, Critical Areas
Management, or Chapter 22D.050 MMC, Clearing, Grading, Filling and Erosion Control, shall be delineated on
the site plans and the development site.
(g) Seasonal Work Limitations. From October 1st through April 30th, clearing, grading, and other soil disturbing
activities are only authorized if silt-laden runoff will be prevented from leaving the site through a combination of
the following:
(i) Site conditions including existing vegetative coverage, slope, soil type and proximity to receiving waters; and
(ii) Limitations on activities and the extent of disturbed areas; and
(iii) Proposed erosion and sediment control measures.
(h) Based on the information provided and/or local weather conditions, the director may expand or restrict the
seasonal limitation on site disturbance. The following activities are exempt from the seasonal clearing and
grading limitations:
(i) Routine maintenance and necessary repair of erosion and sediment control BMPs;
Exhibit C ‐ 21
(ii) Routine maintenance of public facilities or existing utility structures that does not expose the soil or result in
the removal of the vegetative cover to soil; and
(iii) Activities where there is 100 percent infiltration of surface water runoff within the site in approved and
installed erosion and sediment control facilities.
(i) Construction Storm Water Pollution Prevention Plan (SWPPP) Elements. The construction site operator shall
include each of the 12 elements below in the SWPPP and ensure that they are implemented unless site
conditions render the element unnecessary and the exemption from that element is clearly justified in the
SWPPP. The SWPPP shall include both narrative and drawings. All BMPs shall be clearly referenced in the
narrative and marked on the drawings. The SWPPP narrative shall include documentation to explain and justify
the pollution prevention decisions made for the project.
(i) Element 1 – Preserve Vegetation/Mark Clearing Limits.
(A) Prior to beginning land disturbing activities, including clearing and grading, clearly mark all clearing limits,
sensitive areas and their buffers, and trees that are to be preserved within the construction area.
(B) Plastic, metal, or stake wire fencing may be used to mark the clearing limits.
(C) The duff layer, native top soil, and natural vegetation shall be retained in an undisturbed state to the
maximum degree practicable.
(ii) Element 2 – Establish Construction Access.
(A) Construction vehicle access and exit shall be limited to one route, if possible, or two routes for linear
projects such as roadways where more than one access is necessary for large equipment maneuvering.
(B) Access points shall be stabilized with quarry spalls, crushed rock or other equivalent BMP to minimize the
tracking of sediment onto public roads.
(C) Wheel wash or tire baths shall be located on site, if the stabilized construction entrance is not effective in
preventing sediment from being tracked onto public roads.
(D) If sediment is tracked off site, roads shall be cleaned thoroughly at the end of each day, or more frequently
during wet weather. Sediment shall be removed from roads by shoveling or pickup sweeping and shall be
transported to a controlled sediment disposal area.
Exhibit C ‐ 22
(E) Street washing is allowed only after sediment is removed in accordance with subsection (2)(i)(ii)(D) of this
section. Street wash wastewater shall be controlled by pumping back on site or otherwise be prevented from
discharging into systems tributary to waters of the state.
(iii) Element 3 – Control Flow Rates.
(A) Properties and waterways downstream from development sites shall be protected from erosion due to
increases in the velocity and peak volumetric flow rate of storm water runoff from the project site.
(B) Downstream analysis is required. See Chapter 3 of the Stormwater Manual for off-site analysis guidance.
(C) Where necessary to comply with subsection (2)(i)(iii)(A) of this section, storm water retention or detention
facilities shall be constructed as one of the first steps in grading. Detention facilities shall be functional prior to
construction of site improvements (e.g., impervious surfaces).
(D) The director may require pond designs that provide additional or different storm water flow control, if
necessary to address local conditions or to protect properties and waterways downstream from erosion due to
increases in the volume, velocity, and peak flow rate of storm water runoff from the project site.
(E) If permanent infiltration ponds are used for flow control during construction, these facilities should be
protected from siltation during the construction phase.
(iv) Element 4 – Install Sediment Controls.
(A) Storm water runoff from disturbed areas shall pass through a sediment pond, or other appropriate sediment
removal BMP, prior to leaving a construction site or prior to discharge to an infiltration facility. Runoff from fully
stabilized areas may be discharged without a sediment removal BMP, but shall meet the flow control
performance standard of subsection (2)(i)(iii)(A) of this section.
(B) Sediment control BMPs (sediment ponds, traps, filters, etc.) shall be constructed as one of the first steps in
grading. These BMPs shall be functional before other land disturbing activities take place.
(C) BMPs intended to trap sediment on site shall be located in a manner to avoid interference with the
movement of juvenile salmonids attempting to enter off-channel areas or drainages.
(v) Element 5 – Stabilize Soils.
(A) Exposed and unworked soils shall be stabilized by application of effective BMPs that prevent erosion.
Exhibit C ‐ 23
(B) No soils should remain exposed and unworked for more than the time periods set forth below to prevent
erosion:
• During the dry season (May 1st through September 30th): seven days.
• During the wet season (October 1st through April 30th): two days.
(C) The time period may be adjusted by the director, if the director determines that local precipitation data
justify a different standard.
(D) Soils shall be stabilized at the end of the shift before a holiday or weekend if needed based on the weather
forecast.
(E) Soil stockpiles must be stabilized from erosion, protected with sediment trapping measures, and, where
possible, be located away from storm drain inlets, waterways and drainage channels.
(F) Applicable practices include, but are not limited to, temporary and permanent seeding, sodding, mulching,
plastic covering, soil application of polyacrylamide (PAM), the early application of gravel base on areas to be
paved, and dust control.
(G) Soil stabilization measures selected should be appropriate for the time of year, site conditions, estimated
duration of use, and potential water quality impacts that stabilization agents may have on downstream waters
or ground water.
(H) Soil stockpiles must be stabilized from erosion, protected with sediment trapping measures, and, where
possible, be located away from storm drain inlets, waterways and drainage channels.
(vi) Element 6 – Protect Slopes.
(A) Cut and fill slopes shall be designed and constructed in a manner that will minimize erosion.
(B) Soil type and its potential for erosion shall be considered.
(C) Slope runoff velocities shall be reduced by reducing the continuous length of slope with terracing and
diversions, reducing slope steepness, and roughening slope surface.
Exhibit C ‐ 24
(D) Off-site storm water (run-on) or groundwater shall be diverted away from slopes and undisturbed areas with
interceptor dikes, pipes and/or swales. Off-site storm water should be managed separately from storm water
generated on the site.
(E) At the top of slopes, drainage shall be collected in pipe slope drains or channels shall be protected to
prevent erosion. Temporary pipe slope drains shall handle the expected peak 10-minute flow velocity from a
Type 1A, 10-year, 24-hour frequency storm for the developed condition. Alternatively, the 10-year, one-hour
flow rate predicted by an approved continuous runoff model, increased by a factor of 1.6, may be used. The
hydrologic analysis shall use the existing land cover condition for predicting flow rates from tributary areas
outside the project limits. For tributary areas on the project site, the analysis shall use the temporary or
permanent project land cover condition, whichever will produce the highest flow rates. If using the Western
Washington Hydrology Model to predict flows, bare soil areas should be modeled as “landscaped area.”
(F) Drainage shall be provided to remove ground water intersecting the slope surface of exposed soil areas.
(G) Excavated material shall be placed on the uphill side of trenches, consistent with safety and space
considerations.
(H) Check dams shall be placed at regular intervals within constructed channels that are cut down a slope.
(vii) Element 7 – Protect Drain Inlets.
(A) Storm drain inlets made operable during construction shall be protected so that storm water runoff does not
enter the conveyance system without first being filtered or treated to remove sediment.
(B) All approach roads shall be kept clean. All sediment and street wash water shall not be allowed to enter
storm drains without prior and adequate treatment unless treatment is provided before the storm drain
discharges to waters of the state.
(C) Inlet protection devices shall be cleaned or removed and replaced when sediment has filled one-third of the
available storage (unless a different standard is specified by the product manufacturer).
(viii) Element 8 – Stabilize Channels and Outlets.
(A) All temporary on-site conveyance channels shall be designed, constructed, and stabilized to prevent
erosion from the following expected peak flows. Channels shall handle the expected peak 10-minute flow
velocity from a Type 1A, 10-year, 24-hour frequency storm for the developed condition. Alternatively, the 10-
Exhibit C ‐ 25
year, one-hour flow rate predicted by an approved continuous runoff model, increased by a factor of 1.6, may
be used. The hydrologic analysis shall use the existing land cover condition for predicting flow rates from
tributary areas outside the project limits. For tributary areas on the project site, the analysis shall use the
temporary or permanent project land cover condition, whichever will produce the highest flow rates. If using the
Western Washington Hydrology Model to predict flows, bare soil areas should be modeled as “landscaped
area.”
(B) Stabilization, including armoring material, adequate to prevent erosion of outlets, adjacent stream banks,
slopes, and downstream reaches shall be provided at the outlets of all conveyance systems.
(ix) Element 9 – Control Pollutants.
(A) All pollutants, including waste materials and demolition debris, that occur on site shall be handled and
disposed of in a manner that does not cause contamination of storm water.
(B) Cover, containment, and protection from vandalism shall be provided for all chemicals, liquid products,
petroleum products, and other materials that have the potential to pose a threat to human health or the
environment. On-site fueling tanks shall include secondary containment.
(C) Maintenance, fueling and repair of heavy equipment and vehicles shall be conducted using spill prevention
and control measures. Contaminated surfaces shall be cleaned immediately following any spill incident.
(D) Wheel wash or tire bath wastewater shall be discharged to a separate on-site treatment system or to the
sanitary sewer with local sewer district approval.
(E) Application of fertilizers and pesticides shall be conducted in a manner and at application rates that will not
result in loss of chemical to storm water runoff. Manufacturers’ label requirements for application rates and
procedures shall be followed.
(F) BMPs shall be used to prevent or treat contamination of storm water runoff by pH modifying sources. These
sources include, but are not limited to: bulk cement, cement kiln dust, fly ash, new concrete washing and curing
waters, waste streams generated from concrete grinding and sawing, exposed aggregate processes,
dewatering concrete vaults, concrete pumping and mixer washout waters. Construction site operators shall
adjust the pH of storm water if necessary to prevent violations of water quality standards.
(G) Construction site operators shall obtain written approval from the Department of Ecology prior to using
chemical treatment other than CO2 or dry ice to adjust pH.
Exhibit C ‐ 26
(x) Element 10 – Control Dewatering.
(A) Foundation, vault, and trench dewatering water, which have similar characteristics to storm water runoff at
the site, shall be discharged into a controlled conveyance system prior to discharge to a sediment trap or
sediment pond.
(B) Clean, nonturbid dewatering water, such as well-point ground water, can be discharged to systems tributary
to or directly into surface waters of the state, as specified in subsection (2)(i)(viii) of this section, Element 8 –
Stabilize Channels and Outlets, provided the dewatering flow does not cause erosion or flooding of receiving
waters. Clean dewatering water should not be routed through storm water sediment ponds.
(C) Other dewatering disposal options may include: (1) infiltration; (2) transport off site in vehicle, such as a
vacuum flush truck, for legal disposal in a manner that does not pollute state waters; (3) on-site chemical
treatment or other suitable treatment technologies approved by the director; (4) sanitary sewer discharge with
local sewer district approval, if there is no other option; or (5) use of a sedimentation bag with outfall to a ditch
or swale for small volumes of localized dewatering.
(D) Highly turbid or contaminated dewatering water shall be handled separately from storm water.
(xi) Element 11 – Maintain BMPs.
(A) All temporary and permanent erosion and sediment control BMPs shall be inspected, maintained and
repaired as needed to assure continued performance of their intended function in accordance with BMP
specifications.
(B) All temporary erosion and sediment control BMPs shall be removed within 30 days after final site
stabilization is achieved or after the temporary BMPs are no longer needed. Disturbed soil areas resulting from
removal of BMPs or vegetation shall be permanently stabilized.
(xii) Element 12 – Manage the Project.
(A) Development projects shall be phased to the maximum degree practicable and shall take into account
seasonal work limitations.
(B) The construction site operator shall maintain, and repair as needed, all sediment and erosion control BMPs
to assure continued performance of their intended function.
Exhibit C ‐ 27
(C) The construction site operator shall periodically inspect its sites. For projects that disturb one or more
acres, site inspections shall be conducted by a certified erosion and sediment control lead, who shall be
identified in the SWPPP and shall be present on site or on call at all times.
(D) Construction site operators shall maintain, update and implement their SWPPP. Construction site operators
shall modify their SWPPP whenever there is a change in design, construction, operation, or maintenance at the
construction site that has, or could have, a significant effect on the discharge of pollutants to waters of the
state.
(j) Erosivity Waiver. The city may allow construction site operators to qualify for a waiver from the requirement
to submit an SWPPP for review by the city provided the following conditions are met:
(i) The site will result in the disturbance of less than five acres; and the site is not a portion of a common plan of
development or sale that will disturb five acres or greater; and
(ii) The project’s rainfall erosivity factor (“R” Factor) is less than five during the period of construction activity, as
calculated using the Texas A&M University online rainfall erosivity calculator at: http://ei.tamu.edu/. The period
of construction activity begins at initial earth disturbance and ends with final stabilization; and
(iii) The entire period of construction activity falls between June 15th and September 15th; and
(iv) The site or facility has not been declared a significant contributor of pollutants; and
(v) There are no planned construction activities at the site that will result in non-storm water discharges; and
(vi) A waiver is allowed by the city; and
(vii) The construction site operators notify the city of the intention to apply this waiver at least one week prior to
commencing land disturbing activities. The notification must include a summary of the project information used
in calculating the project’s rainfall erosivity factor (see subsection (2)(j)(ii) of this section) and a certified
statement that:
(A) The operator will comply with applicable local storm water requirements; and
(B) The operator will implement appropriate erosion and sediment control BMPs to prevent violations of water
quality standards.
Exhibit C ‐ 28
(3) Minimum Requirement No. 3: Source Control of Pollution. All known, available and reasonable source
control BMPs are required for all projects approved in the city. Source control BMPs must be selected,
designed, and maintained in accordance with Volume IV of the Stormwater Manual or an approved equivalent
manual approved by the Department of Ecology.
(4) Minimum Requirement No. 4: Preservation of Natural Drainage Systems and Outfalls. Natural drainage
patterns shall be maintained, and discharges from the project site shall occur at the natural location, to the
maximum extent practicable. The manner by which runoff is discharged from the project site must not cause a
significant adverse impact to downstream receiving waters and down-gradient properties. All outfalls require
energy dissipation.
(5) Minimum Requirement No. 5: On-Site Storm Water Management. The project site must provide on-site
storm water management BMPs to infiltrate, disperse, and retain storm water runoff on site to the maximum
extent feasible without causing flooding or erosion impacts. Roof downspout control BMPs, functionally
equivalent to those described in Chapter 3 of Volume III of the Stormwater Manual, and dispersion and soil
quality BMPs, functionally equivalent to those in Chapter 5 of Volume V of the Stormwater Manual, shall be
required to reduce the hydrologic disruption of developed sites.
(6) Minimum Requirement No. 6: Runoff Treatment.
(a) Project Thresholds. The following require construction of storm water treatment facilities (see Table
14.15.050(6) below):
(i) Projects in which the total of effective, pollution-generating impervious surface (PGIS) is 5,000 square feet or
more in a threshold discharge area of the project; or
(ii) Projects in which the total of pollution-generating pervious surfaces (PGPS) is three-quarters of an acre or
more in a threshold discharge area, and from which there is a surface discharge in a natural or manmade
conveyance system from the site.
Table 14.15.050(6) Treatment Requirements by Threshold Discharge Area
< 3/4 acres of
PGPS
> 3/4 acres
PGPS < 5,000 sf PGIS > 5,000 sf PGIS
Exhibit C ‐ 29
Treatment Facilities
X X
On-Site Storm Water BMPs X X X X
PGPS = pollution-generating pervious surfaces
PGIS = pollution-generating impervious surfaces
sf = square feet
(b) Treatment Type Thresholds. If the construction project requires storm water treatment, the following
treatment type thresholds shall be used to determine applicable treatment options:
(i) Oil Control. Treatment to achieve oil control applies to projects that have “high-use sites.” High-use sites are
those that typically generate high concentrations of oil due to high traffic turnover or the frequent transfer of oil.
High-use sites include:
(A) An area of a commercial or industrial site subject to an expected average daily traffic (ADT) count equal to
or greater than 100 vehicles per 1,000 square feet of gross building area;
(B) An area of a commercial or industrial site subject to petroleum storage and transfer in excess of 1,500
gallons per year, not including routinely delivered heating oil;
(C) An area of a commercial or industrial site subject to parking, storage or maintenance of 25 or more vehicles
that are over 10 tons gross weight (trucks, buses, trains, heavy equipment, etc.);
(D) A road intersection with a measured ADT count of 25,000 vehicles or more on the main roadway and
15,000 vehicles or more on any intersecting roadway, excluding projects proposing primarily pedestrian or
bicycle use improvements.
(ii) Enhanced Treatment. Enhanced treatment for reduction in dissolved metals is required for the following
project sites that discharge to fish-bearing streams, lakes, or to waters or conveyance systems tributary to fish-
bearing streams or lakes:
(A) Industrial project sites;
(B) Commercial project sites;
(C) Multifamily project sites; and
Exhibit C ‐ 30
(D) High AADT roads as follows:
• Fully controlled and partially controlled limited access highways with Annual Average Daily Traffic (AADT)
counts of 15,000 or more;
• All other roads with an AADT of 7,500 or greater.
However, such sites listed above that discharge directly (or indirectly through a municipal storm sewer system)
to Basic Treatment Receiving Waters (Appendix I-C of the Stormwater Manual), and areas of the above-listed
project sites that are identified as subject to basic treatment requirements, are also not subject to enhanced
treatment requirements. For developments with a mix of land use types, the enhanced treatment requirement
shall apply when the runoff from the areas subject to the enhanced treatment requirement comprise 50 percent
or more of the total runoff within a threshold discharge area.
(iii) Basic Treatment. Basic treatment generally applies to:
(A) Project sites that discharge to the ground, unless:
• The soil suitability criteria for infiltration treatment are met (see Chapter 3 of Volume III of the Stormwater
Manual for soil suitability criteria); or
• The project uses infiltration strictly for flow control – not treatment – and the discharge is within one-quarter
mile of a phosphorus-sensitive lake (use a phosphorus treatment facility), or within one-quarter mile of a fish-
bearing stream or a lake (use an enhanced treatment facility).
(B) Residential projects not otherwise needing phosphorus control as designated by U.S. EPA, the Department
of Ecology, or by the city.
(C) Project sites discharging directly to salt waters, river segments, and lakes listed in Appendix I-C of the
Stormwater Manual.
(D) Project sites that drain to streams that are not fish-bearing, or to waters not tributary to fish-bearing
streams.
(E) Landscaped areas of industrial, commercial, and multifamily project sites, and parking lots of industrial and
commercial project sites that do not involve pollution-generating sources (e.g., industrial activities, customer
parking, storage of erodible or leachable material, wastes or chemicals) other than parking of employees’
Exhibit C ‐ 31
private vehicles. For developments with a mix of land use types, the basic treatment requirement shall apply
when the runoff from the areas subject to the basic treatment requirement comprises 50 percent or more of the
total runoff within a threshold discharge area.
(c) Treatment Facility Sizing – Water Quality Design Storm Volume. The volume of runoff predicted from a 24-
hour storm with a six-month return frequency (a.k.a., six-month, 24-hour storm). Wetpool facilities are sized
based upon the volume of runoff predicted through use of the Natural Resource Conservation Service curve
number equations in Chapter 2 of Volume III of the Stormwater Manual, for the six-month, 24-hour storm.
Alternatively, the ninety-first percentile, 24-hour runoff volume indicated by an approved continuous runoff
model may be used.
(d) Water Quality Design Flow Rate.
(i) Preceding Detention Facilities or When Detention Facilities Are Not Required. The flow rate at or below
which 91 percent of the runoff volume, as estimated by an approved continuous runoff model, will be treated.
Design criteria for treatment facilities are assigned to achieve the applicable performance goal at the water
quality design flow rate (e.g., 80 percent TSS removal).
(ii) Downstream of Detention Facilities. The water quality design flow rate must be the full two-year release rate
from the detention facility.
(A) Alternative methods may be used if they identify volumes and flow rates that are at least equivalent.
(B) That portion of any development project in which the above PGIS or PGPS thresholds are not exceeded in
a threshold discharge area shall apply on-site storm water management BMPs in accordance with subsection
(5) of this section, Minimum Requirement No. 5: On-Site Storm Water Management.
(e) Treatment Facility Selection, Design, and Maintenance. Storm water treatment facilities shall be:
(i) Selected in accordance with the process identified in Chapter 4 of Volume I of the Stormwater Manual;
(ii) Designed in accordance with the design criteria in Volume V of the Stormwater Manual; and
(iii) Maintained in accordance with the maintenance schedule in Volume V of the Stormwater Manual.
Exhibit C ‐ 32
(f) Additional Requirements. The discharge of untreated storm water from pollution-generating impervious
surfaces to ground water is prohibited, except for the discharge achieved by infiltration or dispersion of runoff
from residential sites through use of on-site storm water management BMPs.
(7) Minimum Requirement No. 7: Flow Control.
(a) Applicability. Except as provided below, all projects shall provide flow control to reduce the impacts of storm
water runoff from impervious surfaces and land cover conversions. The requirement below applies to projects
that discharge storm water directly, or indirectly through a conveyance system, into a fresh water.
(i) Flow control is not required for projects that discharge directly to, or indirectly through an MS4 to a water
listed in Appendix I-E of the Stormwater Manual subject to the following restrictions:
(A) Direct discharge to the exempt receiving water does not result in the diversion of drainage from any
perennial stream classified as Types 1, 2, 3, or 4 in the State of Washington Interim Water Typing System, or
Types “S,” “F,” or “Np” in the Permanent Water Typing System, or from any category I, II, or III wetland; and
(B) Flow splitting devices or drainage BMPs are applied to route natural runoff volumes from the project site to
any downstream Type 5 stream or category IV wetland:
• Design of flow splitting devices or drainage BMPs will be based on continuous hydrologic modeling analysis.
The design will assure that flows delivered to Type 5 stream reaches will approximate, but in no case exceed,
durations ranging from 50 percent of the two-year to the 50-year peak flow.
• Flow splitting devices or drainage BMPs that deliver flow to category IV wetlands will also be designed using
continuous hydrologic modeling to preserve pre-project wetland hydrologic conditions unless specifically
waived or exempted; and
(C) The project site must be drained by a conveyance system that is comprised entirely of manmade
conveyance elements (e.g., pipes, ditches, outfall protection, etc.) and extends to the ordinary high water line of
the exempt receiving water; and
(D) The conveyance system between the project site and the exempt receiving water shall have sufficient
hydraulic capacity to convey discharges from future build-out conditions (under current zoning) of the site, and
the existing condition from nonproject areas from which runoff is or will be collected; and
Exhibit C ‐ 33
(E) Any erodible elements of the manmade conveyance system must be adequately stabilized to prevent
erosion under the conditions noted above.
(ii) If the discharge is to a stream that leads to a wetland, or to a wetland that has an outflow to a stream, both
this minimum requirement (Minimum Requirement No. 7) and subsection (8) of this section, minimum
requirement No. 8, apply.
(b) Thresholds. That portion of any development project in which the below thresholds are not exceeded in a
threshold discharge area shall apply on-site storm water management BMPs in accordance with subsection (5)
of this section, Minimum Requirement No. 5: On-Site Storm Water Management. The following require
construction of flow control facilities and/or land use management BMPs that will achieve the standard flow
control requirement for western Washington (see Table 14.15.050(7)):
(i) Projects in which the total of effective impervious surfaces is 10,000 square feet or more in a threshold
discharge area; or
(ii) Projects that convert three-quarters acres or more of native vegetation to lawn or landscape, or convert 2.5
acres or more of native vegetation to pasture in a threshold discharge area, and from which there is a surface
discharge in a natural or manmade conveyance system from the site; or
(iii) Projects that through a combination of effective impervious surfaces and converted pervious surfaces
cause a 0.1 cubic feet per second increase in the 100-year flow frequency from a threshold discharge area as
estimated using the Western Washington Hydrology Model or other model approved in the Stormwater Manual.
Table 14.15.050(7) Flow Control Requirements by Threshold Discharge Area
Flow Control
Facilities
On-Site Storm Water
Management BMPs
< 3/4 acres conversion to lawn/landscape, or < 2.5 acres to
pasture
X
> 3/4 acres conversion to lawn/landscape, or > 2.5 acres to
pasture
X X
< 10,000 square feet of effective impervious area X
Exhibit C ‐ 34
> 10,000 square feet of effective impervious area X X
> 0.1 cubic feet per second increase in the 100-year flood
frequency
X X
(c) Standard Flow Control Requirement. Storm water discharges shall match developed discharge durations to
pre-developed durations for the range of pre-developed discharge rates from 50 percent of the two-year peak
flow up to the full 50-year peak flow. This standard requirement is waived for sites that will reliably infiltrate all
the runoff from impervious surfaces and converted pervious surfaces. The pre-developed condition to be
matched shall be a forested land cover unless:
(i) Reasonable, historic information is available that indicates the site was prairie prior to settlement (modeled
as “pasture” in the Western Washington Hydrology Model); or
(ii) The drainage area of the immediate stream and all subsequent downstream basins have had at least 40
percent total impervious area since 1985. In this case, the pre-developed condition to be matched shall be the
existing land cover condition. Where basin-specific studies determine a stream channel to be unstable, even
though the above criterion is met, the pre-developed condition assumption shall be the “historic” land cover
condition, or a land cover condition commensurate with achieving a target flow regime identified by an
approved basin study.
(d) Additional Requirement. Flow control BMPs shall be selected, designed, and maintained in accordance with
Volume III of the Stormwater Manual or an approved equivalent.
(8) Minimum Requirement No. 8: Wetlands Protection.
(a) Applicability. The requirements below apply only to projects whose storm water discharges into a wetland,
either directly or indirectly through a conveyance system. These requirements must be met in addition to
meeting subsection (6) of this section, Minimum Requirement No. 6: Runoff Treatment.
(b) Thresholds. The thresholds identified in subsection (6) of this section, Minimum Requirement No. 6: Runoff
Treatment, and subsection (7) of this section, Minimum Requirement No. 7: Flow Control, shall also be applied
for discharges to wetlands.
(c) Standard Requirement. Discharges to wetlands shall maintain the hydrologic conditions, hydrophytic
vegetation, and substrate characteristics necessary to support existing and designated uses. The hydrologic
analysis shall use the existing land cover condition to determine the existing hydrologic conditions unless
Exhibit C ‐ 35
directed otherwise. A wetland can be considered for hydrologic modification and/or storm water treatment in
accordance with Guide Sheet 1B in Appendix I-D on the Stormwater Manual.
(d) Additional Requirements. Storm water treatment and flow control facilities shall not be built within a natural
vegetated buffer, except for:
(i) As necessary, conveyance systems as approved by the director; or
(ii) As allowed in wetlands approved for hydrologic modification and/or treatment in accordance with Guide
Sheet 1B in Appendix I-D of the Stormwater Manual.
(9) Minimum Requirement No. 9: Operation and Maintenance. All project submittals must include an operation
and maintenance manual that is consistent with the provisions in Volume V of the Stormwater Manual for all
proposed storm water facilities and BMPs. The party (or parties) responsible for maintenance and operation
shall be identified in the operation and maintenance manual. For private facilities approved by the city, a copy
of the manual shall be retained on site or within reasonable access to the site, and shall be transferred with the
property to the new owner. For public facilities, a copy of the manual shall be retained in the appropriate
department. A log of maintenance activity that indicates what actions were taken shall be kept and be available
for inspection by the city.
1. Minimum Requirement 1 Preparation of Stormwater Site Plans: Preparation of a Stormwater Site Plan is
required for projects meeting the thresholds in Section 14.15.040. Stormwater Site Plans shall use site
appropriate development principles, as required and encouraged by the Marysville Municipal Code, to
retain native vegetation and minimize impervious surfaces to the extent feasible. Stormwater Site Plans
shall be prepared in accordance with Chapter 3 of Volume 1 of the Stormwater Manual.
2. Minimum Requirement 2 Construction Stormwater Pollution Prevention Plan (SWPPP): All new
development and redevelopment projects are responsible for preventing erosion and discharge of
sediment and other pollutants into receiving waters. All projects which result in 2,000 sq. ft. or more of
new plus replaced hard surface area, or which disturb 7,000 sq. ft. or more of land must develop a
Construction Stormwater Pollution Prevention Plan (SWPPP). Projects below those thresholds are not
required to prepare a Construction SWPPP, but must consider all of the Elements for Construction
SWPPPs and develop controls for all elements that pertain to the project site. The City may develop an
abbreviated SWPPP format to meet the SWPPP requirement for project sites that will disturb less than 1
Exhibit C ‐ 36
acre. The SWPPP shall be prepared in accordance with the Stormwater Manual.
3. Minimum Requirement 3 Source Control of Pollution: All known, available and reasonable source control
BMPs are required for all projects approved in the City. Source control BMPs must be selected,
designed, and maintained in accordance with Volume IV of the Stormwater Manual.
4. Minimum Requirement 4 Preservation of Natural Drainage Systems and Outfalls: Natural drainage
patterns shall be maintained, and discharges from the project site shall occur at the natural location, to
the maximum extent practicable. The manner by which runoff is discharged from the project site must
not cause a significant adverse impact to downstream receiving waters and down gradient properties.
All outfalls require energy dissipation.
5. Minimum Requirement 5 On-site Stormwater Management: Except as provided below, the project site
must provide On-site Stormwater Management BMPs in accordance with the project thresholds,
standards, and lists, in the Stormwater Manual, to infiltrate, disperse, and retain stormwater runoff on-site
to the extent feasible without causing flooding or erosion impacts. Projects qualifying as flow control
exempt in accordance with Minimum Requirement 7 do not have to achieve the LID performance
standard, nor consider bioretention, rain gardens, permeable pavement, andor full dispersion if using List
No.1 or List No.2. However, those projects must implement BMP T5.13; BMPs T5.10A, B, or C; and BMP
T5.11 or T5.12, if feasible.
(a) Project Thresholds
(i) Projects triggering only Minimum Requirements 1 through 5 shall either:
A. Use On-site Stormwater Management BMPs from List No.1 for all surfaces within
each type of surface in List No.1; or
B. Demonstrate compliance with the LID Performance Standard. Projects
selecting this option cannot use Rain Gardens. They may choose to use
Bioretention BMPs as described in the Stormwater Manual.
(ii) New development and redevelopment projects triggering Minimum Requirements
1 through 9 for any parcel inside the City must meet the Low Impact Development
Performance Standard and BMP T5.13; or use List No.2 (applicant option).
6. Minimum Requirement 6 Runoff Treatment: The following project thresholds should be administered as
Exhibit C ‐ 37
applicable to projects within the City. Treatment facility sizing, selection, design, maintenance and
additional requirements from the Stormwater Manual also apply.
a) Project Thresholds. When assessing a project against the following thresholds, only consider
those hard and pervious surfaces that are subject to this minimum requirement as determined in
MMC 14.15.040. The following require construction of stormwater treatment facilities:
(i) Projects in which the total of pollution-generating hard surface (PGHS) is 5,000 square
feet or more in a threshold discharge area of the project, or
(ii) Projects in which the total of pollution-generating pervious surfaces (PGPS) – not
including permeable pavements - is three-quarters (3/4) of an acre or more in a threshold
discharge area, and from which there will be a surface discharge in a natural or man-made
conveyance system from the site.
b) Treatment-Type Thresholds
(i) Oil Control: Treatment to achieve Oil Control applies to projects that have “high-use sites.”
High-use sites are those that typically generate high concentrations of oil due to high traffic
turnover or the frequent transfer of oil. High-use sites include:
A. An area of a commercial or industrial site subject to an expected average daily traffic
(ADT) count equal to or greater than 100 vehicles per 1,000 square feet of gross
building area;
B. An area of a commercial or industrial site subject to petroleum storage and transfer in
excess of 1,500 gallons per year, not including routinely delivered heating oil;
C. An area of a commercial or industrial site subject to parking, storage or maintenance
of 25 or more vehicles that are over 10 tons gross weight (trucks, buses, trains,
heavy equipment, etc.);
D. A road intersection with a measured ADT count of 25,000 vehicles or more on the main
roadway and 15,000 vehicles or more on any intersecting roadway, excluding projects
proposing primarily pedestrian or bicycle use improvements.
(ii) Enhanced Treatment: Except where specified below under “ Basic Treatment”, Enhanced
Exhibit C ‐ 38
treatment for reduction in dissolved metals is required for the following project sites that: (1)
discharge directly to fresh waters or conveyance systems tributary to fresh waters designated
for aquatic life use or that have an existing aquatic life use; or (2) uses infiltration strictly for flow
control – not treatment – and the discharge is within ¼ mile of a fresh water designated for
aquatic life use or that has an existing aquatic life use:
A. Industrial project sites,
B. Commercial project sites,
C. Multi-family project sites, and
D. High AADT roads as follows:
Fully controlled and partially controlled limited access highways with Annual Average
Daily Traffic (AADT) counts of 15,000 or more
All other roads with an AADT of 7,500 or greater
Any areas of the above-listed project sites that are identified as subject to Basic Treatment
requirements (below), are not also subject to Enhanced Treatment requirements. For
developments with a mix of land use types, the Enhanced Treatment requirement shall apply
when the runoff from the areas subject to the Enhanced Treatment requirement comprise 50
percent or more of the total runoff within a threshold discharge area.
(iii) Basic Treatment: Basic Treatment is required in the following circumstances:
A. Project sites that discharge to the ground, UNLESS:
The soil suitability criteria for infiltration treatment are met (See Chapter 3, Volume III of
the Stormwater Manual), and alternative pretreatment is provided (see Chapter 6,
Volume V of the Stormwater Manual); or
The project site uses infiltration strictly for flow control – not treatment and the
discharge is within ¼-mile of a phosphorus sensitive lake (use a Phosphorus
Treatment facility), or
The project site is industrial, commercial, multi-family residential, or a high AADT road
Exhibit C ‐ 39
(consistent with the Enhanced Treatment-type thresholds listed above) and is within ¼
mile of a fresh water designated for aquatic life use or that has an existing aquatic life
use. (use an Enhanced Treatment facility).
B. Residential projects not otherwise needing phosphorus control as designated by
USEPA, the Department of Ecology, or by the City;
C. Project sites discharging directly (or indirectly through a municipal separate storm
sewer system) to Basic Treatment Receiving Waters (Appendix I-C of the
Stormwater Manual);
D. Project sites that drain to fresh water that is not designated for aquatic life use, and does
not have an existing aquatic life use; and project sites that drain to waters not tributary to
waters designated for aquatic life use or that have an existing aquatic life use;
E. Landscaped areas of industrial, commercial, and multi-family project sites, and parking lots
of industrial and commercial project sites that do not involve pollution-generating sources
(e.g., industrial activities, customer parking, storage of erodible or leachable material,
wastes or chemicals) other than parking of employees’ private vehicles. For developments
with a mix of land use types, the Basic Treatment requirement shall apply when the runoff
from the areas subject to the Basic Treatment requirement comprise 50 percent or more of
the total runoff within a threshold discharge area.
7. Minimum Requirement 7 Flow Control: The following thresholds should be administered as applicable to
projects within the City. Additional standards and requirements from the Stormwater Manual also apply.
a. Applicability- Except as provided below, projects shall provide flow control to reduce the impacts of
stormwater runoff from hard surfaces and land cover conversions. The requirement below applies to
projects that discharge stormwater directly, or indirectly through a conveyance system, into a fresh
water body. Flow control is not required for projects that discharge directly to, or indirectly through
the MS4 to a water listed in Appendix I-E of the Stormwater Manual subject to the following
restrictions:
(i) Direct discharge to the exempt receiving water does not result in the diversion of
drainage from any perennial stream classified as Types 1, 2, 3, or 4 in the State of
Washington Interim Water Typing System, or Types “S”, “F”, or “Np” in the Permanent
Exhibit C ‐ 40
Water Typing System, or from any category I, II, or III wetland; and
(ii) Flow splitting devices or drainage BMP’s are applied to route natural runoff volumes from
the project site to any downstream Type 5 stream or category IV wetland:
o Design of flow splitting devices or drainage BMP’s will be based on continuous
hydrologic modeling analysis. The design will assure that flows delivered to Type 5
stream reaches will approximate, but in no case exceed, durations ranging from 50
percent of the 2-year to the 50-year peak flow.
o Flow splitting devices or drainage BMP’s that deliver flow to category IV wetlands will
also be designed using continuous hydrologic modeling to preserve pre-project
wetland hydrologic conditions unless specifically waived or exempted by regulatory
agencies with permitting jurisdiction; and
(iii) The project site must be drained by a conveyance system that is comprised entirely of
manmade conveyance elements (e.g., pipes, ditches, outfall protection) and extends to
the ordinary high water line of the exempt receiving water; and
(iv) The conveyance system between the project site and the exempt receiving water shall
have sufficient hydraulic capacity to convey discharges from future build-out conditions
(under current zoning) of the site, and the existing condition from non- project areas
from which runoff is or will be collected; and
(v) Any erodible elements of the man-made conveyance system must be adequately
stabilized to prevent erosion under the conditions noted above; and.
(vi) If the discharge is to a stream that leads to a wetland, or to a wetland that has an
outflow to a stream, both this minimum requirement (Minimum Requirement No.7) and
Minimum Requirement No.8 apply.
b. Thresholds. When assessing a project against the following thresholds, consider only those
impervious, hard, and pervious surfaces that are subject to this minimum requirement as determined
in MMC Section 14.15.040. The following circumstances require achievement of the standard flow
control requirement for western Washington:
(i) Projects in which the total of effective impervious surfaces is 10,000 square feet or more in a
Exhibit C ‐ 41
threshold discharge area, or
(ii) Projects that convert ¾ acres or more of vegetation to lawn or landscape, or convert 2.5 acres
or more of native vegetation to pasture in a threshold discharge area, and from which there is a
surface discharge in a natural or man-made conveyance system from the site, or
(iii) Projects that through a combination of hard surfaces and converted vegetation areas cause a
0.10 cubic feet per second (cfs) increase or greater in the 100-year flow frequency from a
threshold discharge area as estimated using the Western Washington Hydrology Model or other
approved model and one-hour time steps (or a 0.15 cfs increase or greater using 15-minute
time steps). (The 0.10 cfs (one-hour time steps) or 0.15 cfs (15-minute time steps) increase
should be a comparison of the post- project runoff to the existing condition runoff. For the
purpose of applying this threshold, the existing condition is either the pre-project land cover, or
the land cover that existed at the site as of a date when the local jurisdiction first adopted flow
control requirements into code or rules.)
8. Minimum Requirement 8 Wetlands Protection: The following thresholds should be administered as
applicable to projects within the City. Additional standards and requirements from the Stormwater Manual
also apply.
a. Applicability The wetland protection requirements in the Stormwater Manual apply only to projects
whose stormwater discharges into a wetland, either directly or indirectly through a conveyance system.
b. Thresholds The thresholds identified in Minimum Requirement #6 – Runoff Treatment, and
Minimum Requirement 7 – Flow Control shall also be applied to determine the applicability of this
requirement to discharges to wetlands.
9. Minimum Requirement 9 Operation and Maintenance: All project submittals must include an operation
and maintenance manual that is consistent with the provisions in Volume V of the Stormwater Manual for
proposed stormwater facilities and BMPs. The party (or parties) responsible for maintenance and
operation shall be identified in the operation and maintenance manual. For private facilities approved by
the City, a copy of the operation and maintenance manual shall be retained on-site or within reasonable
access to the site, and shall be transferred with the property to the new owner. For public facilities, a
copy of the operation and maintenance manual shall be retained in the appropriate department. A log of
maintenance activity that indicates what actions were taken shall be kept and be available for inspection
by the City.
Exhibit C ‐ 42
14.15.062 Low impact development (LID) – Alternative drainage standards.
(1) Low impact BMPs are an alternative to conventional storm water management systems that rely on
detention ponds and closed conveyance. Instead, low impact development is intended to manage runoff close
to the source of generation and to mimic the predeveloped hydrologic condition of a site. This is accomplished
first through minimizing the impervious surface coverage and second by managing runoff through dispersion,
infiltration, evapotranspiration, or a combination of these approaches. Low impact development (LID) is a
stormwater management and land development strategy utilized in site design and construction that
emphasizes conservation and use of on-site natural features integrated with engineered, small-scale hydrologic
controls to mimic natural hydrologic functions. Implementation of LID benefits streams, lakes, and Puget Sound
by moderating the impacts of stormwater runoff generated by the built environment. LID techniques are the
preferred and commonly-used approach to site development with traditional, structural stormwater
management solutions used where LID is infeasible. Low impact development best management practices (LID
BMPs) are described in the Stormwater Manual and the Low Impact Development Technical Guidance Manual
for Puget Sound, published by the Puget Sound Partnership, and Washington State University Extension. LID
site design objectives are:
(a) To retain or restore native forest cover to capture, infiltrate, and evaporate all or a portion of the rainfall
on a site;
(b) To confine development to the smallest possible footprint and minimize land disturbance and site
grading;
(c) To preserve or restore the health and water-holding capacity of soils;
(d) To incorporate natural site features that promote stormwater infiltration;
(e) To minimize all impervious surfaces and especially those that drain to conventional piped
conveyances;
(f) To manage stormwater through infiltration, bioretention, and dispersion; and
(g) To manage stormwater runoff as close to its origin as possible in small, dispersed facilities. (Ord. 2852
§ 10 (Exh. A), 2011).
(h) Locate buildings away from critical areas and soils that provide effective infiltration.
Exhibit C ‐ 43
(i) Increase reliability of the stormwater management system by providing multiple or redundant LID flow
control practices.
(j) Integrate stormwater controls into the development design and utilize the controls as amenities to
create a multifunctional landscape.
(1)(2) Use of LID BMPs may reduce or eliminate the need for conventional detention facilities but does not
remove the obligation to comply with the minimum requirements in MMC 14.15.050. A variety of BMPs to
minimize impervious surfaces and to manage storm water have been developed and tested for use in western
Washington. These BMPs and the overall LID approach are described in the Stormwater Manual and the Low
Impact Development Technical Guidance Manual for Puget Sound.
(3) The menu of LID BMPs identified in the Stormwater Manual and the Low Impact Development
Technical Guidance Manual for Puget Sound are accepted for use in storm water site plans to address the
minimum requirements for flow control and runoff treatment in MMC 14.15.050., Ssubject to the specifications,
performance standards, and design criteria in the Stormwater Manual, and City of Marysville Engineering
Design and Development standards and LID Technical Guidance Manual for Puget Sound, review and
approval under this chapter, and Title 22 Chapter 22C.260 MMC, as applicable, and the requirements and
limitations below.
(a) Tree retention, tree planting and dispersion into native vegetation areas shall be performed per the
applicable Stormwater Manual BMPs, and the following:
(i) An arborist report may be required.
(ii) Tree species to be preserved or planted should be consistent with Appendix V-E
Recommended Newly Planted Tree Species for Flow Control Credit in the Stormwater
manual.
(iii) Monitoring and maintenance of plants shall be required in accordance with MMC
22E.010.260.
(iv) Development within protected native vegetated areas shall be limited to biofiltration swales,
stormwater dispersion facilities, pervious pedestrian trails, and approved surface water
restoration projects. Activities within the protected native growth areas shall be limited to
passive recreation, removal of invasive species, amendment of disturbed soils consistent with
all applicable regulations, and planting of native vegetation. Development shall be consistent
with critical areas requirements and restrictions in Chapter 22E.010 MMC.
Exhibit C ‐ 44
(v) A permanent protective mechanism shall be legally established to ensure that the required
protected native vegetated area is preserved and protected in perpetuity in a form that is
acceptable to the city and filed with the county auditor’s office. A permanent protected native
vegetated area shall be established using one of the following mechanisms:
Placement in a separate nonbuilding tract owned in common by all lots within a
subdivision;
Covered by a protective easement or public or private land trust dedication;
Preserved through an appropriate permanent protective mechanism that provides the
same level of permanent protection as subsection (8)(a) of this section as determined
by the community development director or hearing examiner.
(vi) Restrictions on the future use of the protective native vegetated area shall be recorded on the
face of the final plat, short plat, binding site plan, or site plan.
(a)(b) The duff layer and native topsoils shall be retained in an undisturbed state to the maximum
extent practicable. If a development project triggers Minimum Requirement 5 then BMP T5.13 Post
Construction Soil Quality and Depth shall be implemented per the Stormwater Manual, see MMC
14.15.040 for the minimum requirement thresholds.
(1) The city engineer may approve the following LID BMPs to meet water quality treatment requirements:
(a) Full Dispersion. Sites that are approved for full dispersion, consistent with the standards in the LID
Technical Guidance Manual for Puget Sound, are not required to provide water quality treatment.
(b) Bioretention. Any storm water runoff that infiltrates through the imported soil mix in an approved
bioretention facility will have received the equivalent of enhanced treatment. Where bioretention is
intended to fully meet treatment requirements, facilities shall be designed, using an approved continuous
runoff model, to infiltrate 60 percent of the developed two-year peak flow.
(2) In addition to the requirements in MMC 14.15.065, applicants for LID BMPs shall provide a site assessment.
The site assessment shall include the following, unless waived or modified by the city engineer:
(a) A mapped inventory of existing vegetation and description of tree cover and understory;
Exhibit C ‐ 45
(b) A mapped inventory of wetlands and streams and required buffers under Chapter 22E.010 MMC on
the site;
(c) A survey prepared by a registered land surveyor or other licensed professional to conduct surveys
showing existing development, including utility infrastructure, on and adjacent to the site, major and
minor hydrologic features, including seeps, springs, closed depression areas, drainage swales, and
topographic relief at two-foot contours;
(d) The location of all existing and proposed lot lines and easements;
(e) A soils report by a licensed geotechnical engineer or licensed engineering geologist. The report shall
identify:
(i) Underlying soils on the site, utilizing soil pits and soil grain analysis to assess infiltration
capability. The frequency and distribution of test pits shall be adequate to direct placement of the
roads and structures away from soils that can most effectively infiltrate storm water;
(ii) Topographic features that may act as natural storm water storage or conveyance and
underlying soils that provide opportunities for storage and partial infiltration;
(iii) Depth to ground water;
(iv) Landslide hazard areas on the site and the distance to slopes over 25 percent or landslide
hazard areas within 500 feet of the site;
(f) Flood hazard areas on or adjacent to the site;
(g) SEPA environmental checklist.
(3) Additional studies may be required to address potential impacts to down-slope properties.
(4) Restrictions on conversion of drainage facilities shall be recorded on the face of the plat.
(5) A covenant and easement shallmay also be required to be recorded with the Snohomish County auditor’s
office for each lot containing or served by LID BMPbioretention facilities in a form approved by the city
attorney. The covenant shall identify requirements and liability for preservation and maintenance of low impact
development facilities approved under this chapter and privately held in individual or shared undivided
ownership or intended for public ownership. The
Exhibit C ‐ 46
(6) An easement shall be granted for city access to low impact development facilities on private property to
allow inspection, emergency maintenance, and repair.
14.15.065 Contents of a storm water site plan.
(1) Stormw Water Site Plan Required. New development and redevelopment projects must submit a storm
water site plan, prepared using Volume I Chapter 3 of the adopted Stormwater Manual for approval by the
department as required in MMC 14.15.040.
(2) Contents of Plan. In addition to the requirements described in MMC 14.15.050 and the Stormwater Manual,
an off-site analysis report shall be required.
Exhibit C ‐ 47
14.15.120 Inspections – Construction.
All activities regulated by this chapter shall be inspected by the engineer and/or public works department.
Projects shall be inspected at various stages of the work to determine that adequate control is being exercised.
Stages of work requiring inspection include, but are not limited to, preconstruction; installation of BMPs; land-
disturbing activities; installation of utilities, landscaping, retaining walls; and completion of project. When
required by the director or designee, a special inspection and/or testing shall be performed.
The holder of any permit or approval issued subject to a detailed drainage plan shall arrange with the engineer
for scheduling the following inspections:
(1) Initial Inspection. Inspection prior to clearing and construction will apply to sites with a high potential for
sediment damage, as identified by the applicant during civil review based on definitions and
requirements of Appendix 7 of the Western Washington Phase II Municipal Stormw Water Permit;
(2) Grading Preparation. Whenever work on the site preparation, grading, excavations, or fill is ready to be
commenced, but in all cases prior thereto subject also to provisions of MMC 22D.050.070;
(3) Rough Grading. When all rough grading has been completed;
(4) Soils Approval. This inspection/approval applies when engineered soils, bioretention soil mixes,
compost amended soils, soils to meet BMP T5.13 Post Construction Soil Quality and Depth from
Chapter 5, Volume V of the Stormwater Manual, or other specific soil mixes are used as a design
feature of a stormwater facility. The developer must demonstrate that the soil mixes approved on the
plans are used for construction.
(3)(5) (4) Bury Inspection. Prior to burial of any underground drainage structure;
(4)(6) (5) Finish Grading. When all work including installation of all drainage structures and other
protective devices has been completed;
(5)(7) (6) Planting. When erosion control planting shows active growth;
(6)(8) (7) System-wide inspections for residential developments will take place after all flow control
and water quality treatment facilities are completed during the period of heaviest house construction to
identify maintenance needs and enforce compliance with maintenance standards as needed.
(9) When Low Impact Development BMP’s or permanent Stormwater Treatment and Flow Control
BMPs/Facilities are installed that are designed to infiltrate, the City may require the permit holder to
verify proper installation and function. A licensed geotechnical engineer or other qualified personnel,
as approved by the City, shall follow the testing procedures outlined in the City of Marysville
Engineering Design and Development Standards section 3-809 for permeable pavement and the
Exhibit C ‐ 48
methods outlined in the Stormwater Manual for other facility types. Permit holders are responsible for
cost of testing and ensuring all facilities meet design standards and specifications
(10) A final inspection by the City will be required at the end of the 2-year maintenance bond period. The
Developer will be responsible for repairing any deficiencies found as a result of the City inspection.
In some circumstances not all of the above inspections may be necessary. It shall be the discretion of the
public works director or designee to waive or combine any of the above inspections as dictated by conditions.
The public works director or designee shall inspect the work and shall either approve the same or notify the
applicant in writing in what respects there has been failure to comply with the requirements of the approved
plan. Any portion of the work which does not comply shall be promptly corrected by the applicant. The public
works director or designee may make unscheduled site inspections to ensure compliance. Uncorrected
violations will be subject to the provisions of MMC Chapter 4.02 MMC, Enforcement Procedures 14.15.190.
14.15.130 Bonds and liability insurance required.
The department is authorized to require all persons constructing retention/detention, low impact development,
or other drainage system features to post surety or cash bonds. Where such persons have previously posted,
or are required to post, other such bonds on the facility itself or on other construction related to the facility, such
person may, with the permission of the public works director or designee, and to the extent allowable by law,
combine all such bonds into a single bond; provided, that at no time shall the amount thus bonded be less than
the total amount which would have been required in the form of separate bonds; and provided further, that such
a bond shall on its face clearly delineate those separate bonds which it is intended to replace.
(1) Construction Bond. Prior to commencing construction, the person constructing the facility shall post a
construction bond in an amount sufficient to cover the cost of performing said construction per the approved
drainage plans. Alternatively, an equivalent cash deposit to an escrow account administered by a local account
bank may be allowed at the city’s option.
(2) Maintenance Bond. After satisfactory completion of the facilities and release of the construction bond by the
city, the person constructing the facility shall commence a two-year period of satisfactory maintenance of the
facility. The City may require the person constructing the facility to verify that the stormwater facilities are
functioning as designed. A cash bond, to be used at the discretion of the city and, to correct deficiencies in said
maintenance affecting public health, safety, and welfare, must be posted and maintained throughout the two-
year maintenance period. The amount of the cash bond shall be determined by the public works director or
Exhibit C ‐ 49
designee. In addition, at the discretion of the city, a surety bond or cash bond to cover the cost of design
defects or failures in workmanship shall also be posted and maintained through the two-year maintenance
period. Alternatively, an equivalent cash deposit to an escrow account administered by a local account bank
may be allowed, at the city’s option.
(3) Liability Policy. The person constructing the facility shall maintain a liability policy in an amount to be
determined by the city which shall name the city of Marysville as an additional insured and which shall protect
the city from any liability for any accident, negligence, failure of the facility, or any other liability whatsoever,
relating to the construction or maintenance of the facility. The liability policy shall be maintained for the duration
of the facility by the owner of the facility; provided, that in the case of facilities assumed by the city for
maintenance pursuant to MMC 14.15.140, the liability policy shall be terminated when the city maintenance
responsibility commences.
14.15.140 City assumption of maintenance.
The city may assume the maintenance of storm water drainage system facilities after the expiration of the two-
year maintenance period if:
(1) Conveyance to the city occurred per MMC 14.03.420;
(2) All of the requirements of this chapter have been fully complied with;
(3) The facilities have been inspected and approved by the department after two years of operation;
(4) All necessary easements entitling the city to properly maintain the facility have been conveyed to the
city.
(5) All stormwater drainage system features including but not limited to ponds, vaults, CB’s, Control
Structures, shall be cleaned to a condition acceptable to the City prior to assumption.
(4)(6) The developer has supplied to the City an accounting of capital, construction, and operation
and maintenance expenses or other items, for the drainage facilities up to the end of the two-year
period, for the purposes of establishing the basis for future bonding requirements for other
developments.
14.15.155 Stormwater Covenant and Easement
A drainage covenant and easement shall be recorded for all private stormwater treatment and flow control
facilities. The covenant and easement shall be in a form acceptable to the City Attorney and shall provide the
Exhibit C ‐ 50
right of ingress and egress, and the right to perform emergency maintenance. The covenant and easement
shall include a description of the property, facility(ies), and the maintenance responsibilities. The covenant shall
be recorded with the Snohomish County Auditor’s Office against the title of the property and run with the land to
all successors and assigns.
Exhibit D – Chapter 14.16
51
14.16.040 Maintenance of low impact development (LID) facilities.
The city shall inspect LID facilities and monitor the ongoing function of both private and public facilities. Routine
maintenance, such as trash removal, weeding, mulching and pruning of LID facilities, shall be performed on
public facilities in accordance with the maintenance requirements outlined in the Stormwater Manual or the
most current edition of the LID Technical Guidance Manual for Puget Sound, and as specified in city standards,
maintenance specifications, and any recorded maintenance agreements.
Exhibit E – Chapter 14.17
52
14.17.035 Maintenance of low impact development (LID) facilities.
(1) Approved LID facilities, which are located on private property or in public street rights-of-way but dedicated
to private ownership, shall be cleaned, maintained and protected in continuous compliance with this title, the
standards and specifications of the city, and any recorded maintenance agreements. Responsibility for such
work shall be borne by the owner of the underlying property or parties with shared ownership interest.
(2) Property owners shall inspect and maintain approved LID facilities in accordance with the maintenance
requirements set forth in the Stormwater Manual, or the most current edition of the LID Technical Guidance
Manual for Puget Sound as needed, or as specified in said manual, and in city standards, maintenance
specifications, and any recorded maintenance agreements.
(3) If an approved LID facility required to be maintained by a private property owner fails to perform as
designed due to lack of maintenance, the city has the authority to perform the necessary maintenance, and to
recoup the costs incurred from the property owner directly or by liening the property, and to revoke any surface
water fee discounts given for the LID facility.
Exhibit F – Chapter 14.21
53
14.21.030 Definitions.
(1) “AKART” means all known, available, and reasonable methods of prevention, control, and treatment. See
also the State Water Pollution Control Act, RCW 90.48.010 and 90.48.520.
(2) “Best management practices (BMPs)” means schedules of activities, prohibitions of practices, general good
housekeeping practices, pollution prevention and educational practices, maintenance procedures, and
structural or managerial practices to prevent or reduce the discharge of pollutants directly or indirectly to storm
water, receiving waters, or storm water conveyance systems. BMPs also include treatment practices, operating
procedures, and practices to control site runoff, spillage or leaks, sludge or water disposal, or drainage from
raw materials storage.
(3) “Clean Water Act” means the federal Water Pollution Control Act (33 U.S.C. Section 1251 et seq.), and any
subsequent amendments thereto.
(4) “Director of public works” or “director” means the director of the public works department or his/her
designee.
(5) “Ground water” means water in a saturated zone or stratum beneath the surface of the land or below a
surface water body.
(6) “Hazardous materials” means any material, including any substance, waste, or combination thereof, which
because of its quantity, concentration, or physical, chemical, or infectious characteristics may cause, or
significantly contribute to, a substantial present or potential hazard to human health, safety, property or the
environment when improperly treated, stored, transported, disposed of, or otherwise managed.
(7) “Hyperchlorinated” means water that contains more than 10 mg/liter chlorine.
(8) “Illicit discharge” means any direct or indirect non-storm water discharge to the city’s storm drain system,
except as expressly exempted by this chapter.
(9) “Illicit connection” means any manmade conveyance that is connected to a municipal separate storm sewer
without a permit, excluding roof drains and other similar type connections. Examples include sanitary sewer
connections, floor drains, channels, pipelines, conduits, inlets, or outlets that are connected directly to the
municipal separate storm sewer system.
Exhibit F ‐ 54
(10) “Municipal separate storm sewer system (MS4)” means a conveyance or system of conveyances,
including roads with drainage systems, municipal streets, catch basins, curbs, gutters, ditches, manmade
channels, or storm drains, which are:
(a) Owned or operated by the city of Marysville;
(b) Designed or used for collecting or conveying storm water;
(c) Not part of a publicly owned treatment works (POTW) (“POTW” means any device or system used in
treatment of municipal sewage or industrial wastes of a liquid nature which is publicly owned); and
(d) Not a combined sewer (“combined sewer” means a system that collects sanitary sewage and storm
water in a single sewer system).
(11) “National Pollutant Discharge Elimination System (NPDES) storm water discharge permit” means a permit
issued by the Environmental Protection Agency (EPA) (or by the Washington Department of Ecology under
authority delegated pursuant to 33 U.S.C. Section 1342(b)) that authorizes the discharge of pollutants to waters
of the United States, whether the permit is applicable on an individual, group, or general area-wide basis.
(12) “Non-storm water discharge” means any discharge to the storm drain system that is not composed entirely
of storm water.
(13) “Person” means any individual, association, organization, partnership, firm, corporation or other entity
recognized by law and acting as either the owner of a premises or as the owner’s agent.
(14) “Pollutant” means anything which causes or contributes to pollution. Pollutants may include, but are not
limited to: paints, varnishes, and solvents; oil and other automotive fluids; nonhazardous liquid and solid wastes
and yard wastes; refuse, rubbish, garbage, litter, or other discarded or abandoned objects and accumulations,
so that same may cause or contribute to pollution; floatables; pesticides, herbicides, and fertilizers; hazardous
substances and wastes; sewage, fecal coliform and pathogens; dissolved and particulate metals; animal
wastes; wastes and residues that result from constructing a building or structure; and noxious or offensive
matter of any kind.
(15) “Premises” means any building, lot, parcel of land, or portion of land, whether improved or unimproved,
including adjacent sidewalks and parking strips.
Exhibit F ‐ 55
(16) “Storm or storm water drainage system” means publicly owned facilities, including the city’s municipal
separate storm sewer system, by which storm water is collected and/or conveyed, including but not limited to
any roads with drainage systems, municipal streets, gutters, curbs, inlets, piped storm drains, pumping
facilities, retention and detention basins, natural and humanmadehuman made or altered drainage channels,
reservoirs, and other drainage structures.
(17) “Storm water” means runoff during and following precipitation and snowmelt events, including surface
runoff, and drainage or interflow.
14.21.050 Allowable discharges.
The following types of discharges shall not be considered illegal discharges for the purposes of this chapter
unless the director determines that the type of discharge, whether singly or in combination with others, is
causing or is likely to cause pollution of surface water or ground water:
(1) Diverted stream flows.
(2) Rising ground waters.
(3) Uncontaminated ground water infiltration –as defined in 40 CFR CFR 35.2005(b)(20).
(4) Uncontaminated pumped ground water.
(5) Foundation drains.
(6) Air conditioning condensation.
(7) Irrigation water from agricultural sources that is commingled with urban storm water.
(8) Springs.
(9) Uncontaminated Wwater from crawl space pumps.
(10) Footing drains.
(11) Flows from riparian habitats and wetlands.
(12) Discharges from emergency fire fighting activities.
Exhibit F ‐ 56
14.21.060 Conditional discharges.
The following types of discharges shall not be considered illegal discharges for the purposes of this chapter, if
they meet the stated conditions, or unless the director determines that the type of discharge, whether singly or
in combination with others, is causing or is likely to cause pollution of surface water or ground water:
(1) Potable water, including but not limited to water from water line flushing, hyperchlorinated water line
flushing, fire hydrant system flushing, and pipeline hydrostatic test water. These planned discharges shall be
de-chlorinated to a total residual chlorine concentration of 0.1 parts per million or less, pH-adjusted, if
necessary and volumetrically and velocity in volumes and velocities controlled to prevent re-suspension of
sediments in the storm water system.
(2) Lawn watering and other irrigation runoff. These discharges shall be minimized as set forth in Chapter 14.09
MMC.
(3) De-chlorinated swimming pool, spa and hot tub discharges. These discharges shall be de-chlorinated to a
total residual chlorine concentration of 0.1 parts per million or less, pH-adjusted and reoxygenized if necessary,
volumetrically and velocity controlled to prevent re-suspension of sediments in the storm water system.
Discharges shall be thermally controlled to prevent and increase in temperature of the receiving water.
Swimming pool cleaning waste water and filter backwash shall not be discharged to the storm water system.
(4) Street and sidewalk wash water, water used to control dust, and routine external building wash down that
does not use detergents. These discharges shall be permitted, if the amount of street wash and dust control
water used is minimized. At active construction sites, street sweeping must be performed prior to washing the
street.
(5) Non-storm water discharges covered by another NPDES permit. These discharges shall be in full
compliance with all requirements of the permit, waiver, or order and other applicable laws and regulations.
(6) Other non-storm water discharges. These discharges shall be in compliance with the requirements of a
storm water pollution prevention plan (SWPPP) reviewed and approved by the city, which addresses control of
such discharges by applying AKART to prevent contaminants from entering surface or ground water.
Exhibit G – Chapter 22A.020
57
22A.020.170 “P” definitions.
“Painted sign” means a sign painted on a wall, fence or other structure and not lighted by internal illumination.
A painted sign is a type of wall sign.
“Panhandle lot” means a lot where the front and rear lot lines conform to zoning code requirements for lot
dimensions and lot sizes except for the panhandle. The panhandle is a narrow strip of land which does not,
itself, meet the full frontage or width requirements of a lot and will be utilized principally for access purposes
from an improved public right-of-way.
Parcel. See definition for “Lot.”
“Park” means a site designed or developed for recreational use by the public including, but not limited to:
(1) Indoor facilities, such as:
(a) Gymnasiums;
(b) Swimming pools; or
(c) Activity centers; and
(2) Outdoor facilities, such as:
(a) Playfields;
(b) Fishing areas; or
(c) Picnic and related outdoor activity areas; and
(3) Areas and trails for:
(a) Hikers;
(b) Equestrians;
(c) Bicyclists; or
(d) Off-road recreational vehicle users.
Exhibit G ‐ 58
“Party of record” or “POR” means a person who has submitted written comments, testified, asked to be notified
or is the sponsor of a petition entered as part of the official city record on a specific development proposal.
“People with functional disabilities” means:
(1) A person who because of a recognized chronic physical or mental condition or disease is functionally
disabled to the extent of:
(a) Needing care, supervision or monitoring to perform activities of daily living or instrumental
activities of daily living; or
(b) Needing support to ameliorate or compensate for the effects of a functional disability so as to
lead as independent a life as possible; or
(c) Having a physical or mental impairment which substantially limits one or more of such
person’s major life activities; or
(d) Having a record of having such an impairment; or
(2) Being regarded as having such an impairment, but such term does not include current, illegal use of or
active addiction to a controlled substance.
“Permitted use” means any use authorized or permitted alone or in conjunction with another use in a specified
district and subject to the limitations of the regulations of such use district.
“Person” means any individual, corporation, partnership, association, governmental body, state agency or other
entity whatsoever.
“Pet daycare” means any commercial facility where four or more dogs, or other pet animals, are left by their
owners during the daytime for periods of supervised social interaction in play groups with other animals of the
same species. Supervised social interaction occurs during the majority of the time the pets are at the facility.
“Planned action” means a significant development proposal as defined in RCW 43.21C.031 (SEPA) as
amended.
“Plans” means planning documents, which are developed by the various departments of the city, pertaining to
the orderly development of public facilities.
Exhibit G ‐ 59
“Plat” means the map or representation of a subdivision, showing thereon the division of a tract or parcel of
land into lots, blocks, streets and alleys or other divisions and dedications.
“Plat – final” means a map or representation of a subdivision, showing thereon the division of a tract or parcel
of land into lots, blocks, streets, alleys, or other divisions and dedications and containing all elements and
requirements set forth in the chapter and Chapter 58.17 RCW.
“Plat – preliminary” means:
(1) A neat and approximate drawing of a proposed subdivision showing the general layout of streets, alleys,
lots, blocks, and other elements of a subdivision required by this chapter and Chapter 58.17 RCW.
(2) The preliminary plat shall be the basis for the approval or disapproval of the general layout of a subdivision.
“Plug-in hybrid electric vehicle” or “PHEV” means an electric vehicle that (1) contains an internal combustion
engine and also allows power to be delivered to drive wheels by an electric motor; (2) charges its battery
primarily by connecting to the grid or other off-board electrical source; (3) may additionally be able to sustain
battery charge using an on-board internal-combustion-driven generator; and (4) has the ability to travel
powered by electricity.
“Pole sign” means a freestanding sign hung from or supported by vertical standing pipe(s), wood beam(s) or
other material(s) that are affixed to the ground at one end and to the sign at the other end if the support(s) are
clearly visible. This definition also includes a pylon sign.
“Portable sign” means any movable sign not permanently attached to the ground or a building and easily
removable using ordinary hand tools.
“Preliminary approval” means an official action on a proposed subdivision or short subdivision that refers to
placement of specific conditions which must be complied with before final approval may be granted.
“Primary association area” means the area is used on a regular basis, is in close association with, or is
necessary for the proper functioning of the habitat of a critical species. “Regular basis” means that the habitat
area is normally or usually known to contain a critical species, or based on known habitat requirements of the
species the area is likely to contain the critical species. Regular basis is species and population dependent.
Species that exist in low numbers may be present infrequently yet rely on certain habitat types.
Exhibit G ‐ 60
“Priority species” or “priority wildlife species” means wildlife species of concern due to their population status
and sensitivity to habitat alteration as identified by the Washington State Department of Wildlife.
“Private storm water management facility” means a surface water control structure installed by a project
proponent to retain, detain, infiltrate or otherwise limit runoff and improve water quality from an individual or
group of developed sites specifically served by such structure and is privately owned. This definition does not
include biofiltration swales.
“Professional office” means an office used as a place of business by licensed professionals, or persons in other
generally recognized professions, which use training or knowledge of a technical, scientific or other academic
discipline as opposed to manual skills, and which does not involve outside storage or fabrication, or on-site sale
or transfer of commodities; including the following:
(1) Insurance agents, brokers and service;
(2) Real estate agents and planning directors;
(3) Income tax return preparation services;
(4) Legal services;
(5) Engineering, architectural and surveying services;
(6) Accounting, auditing and bookkeeping services; and
(7) Management and public relations services.
“Projecting sign” means a sign which projects from and is supported by a wall or parapet of a building with the
display surface of the sign in a plane perpendicular to or approximately perpendicular to the wall. See also
“Canopy sign.”
“Promotional sign” means posters, pennants, banners or streamers, balloons, searchlights, clusters of flags,
strings of twirlers or propellers, flares, and other displays of a carnival nature used to promote a grand opening
or sales events.
“Property boundary” means the surveyed line at ground surface which separates the real property owned,
rented, or leased by one or more persons from that owned, rented, or leased by one or more other persons,
and its vertical extension.
Exhibit G ‐ 61
“Public agency” means any agency, political subdivision or unit of local government of this state including, but
not limited to, municipal corporations, special purpose districts and local service districts, any agency of the
state of Washington, the United States or any state thereof or any Indian tribe recognized as such by the
federal government.
“Public agency office” means an office for the administration of any governmental activity or program, with no
outdoor storage and including, but not limited to, the following uses:
(1) Executive, legislative, and general government;
(2) Public finance, taxation, and monetary policy;
(3) Administration of human resource programs;
(4) Administration of environmental quality and housing programs;
(5) Administration of economic programs;
(6) International affairs;
(7) Legal counsel and prosecution; and
(8) Public order and safety.
“Public agency training facility” means an establishment or school for training state and local law enforcement,
fire safety, National Guard or transit personnel and facilities including but not limited to:
(1) Dining and overnight accommodations;
(2) Classrooms;
(3) Shooting ranges;
(4) Auto test tracks; and
(5) Fire suppression simulations.
“Public agency yard” means a facility for open or enclosed storage, repair, and maintenance of vehicles,
equipment, or related materials, excluding document storage.
Exhibit G ‐ 62
“Public improvements” include but are not limited to streets, roads, storm drainage systems, sanitary sewage
facilities, water mains, pedestrian and landscaping improvements which comply with adopted city standards
and are dedicated to the city for public use.
“Public safety sign” means a sign advertising a location where public safety services are available.
“Public storm water management facility” means a surface water control structure installed by a project
proponent to retain, detain, infiltrate or otherwise limit runoff and improve water quality from an individual or
group of developed sites specifically served by such structure and dedicated to the city. This definition does not
include biofiltration swales.
“Public street” means a right-of-way which provides vehicular and pedestrian access to adjacent properties,
which the city has officially accepted into its street system.
Exhibit H – Chapter 22C.120
63
22C.120.170 Landscaping – Soil amendment.
All landscaped and lawn areas, except areas within the dripline of preserved trees, shall be amended per BMP
T5.13 Post Construction Soil Quality and Depth in Volume V of the Washington Department of Ecology 2012
Stormwater Management Manual for Western Washington, as may be amended hereafter. with four inches of
well-composted organic matter mixed into the top eight inches of soil or shall have an organic content of
between eight and 13 percent dry weight and a pH suitable for proposed plantings. Deeper soil amendment will
provide improved growing medium and increased water holding capacity.
Exhibit I – Chapter 22C.130
64
22C.130.050 Development standards.
(1) Purpose. The parking area layout standards are intended to promote safe circulation within the parking area
and provide for convenient entry and exit of vehicles.
(2) Where These Standards Apply. The standards of this section apply to all vehicle areas whether required or
excess parking.
(3) Improvements.
(a) Paving.
(i) In order to control dust and mud, all vehicle areas must be surfaced with a minimum all-
weather surface. Such surface shall be specified by the city engineer. Alternatives to the
specified all-weather surface may be provided, subject to approval by the city engineer.
Gravel surfacing is not considered an all-weather surface.
(ii) The applicant shall be required to prove that the alternative surfacing provides results
equivalent to paving. If, after construction, the city determines that the alternative is not
providing the results equivalent to paving or is not complying with the standards of
approval, paving shall be required.
(iii) Parks, agricultural and similar uses, and developments providing surplus parking, are
exempt from the all-weather surface requirement, provided, all surfacing must provide for
the following minimum standards of approval:
(A) Gravel parking facilities shall be surfaced with no less than three inches of
crushed gravel.
(B) Dust is controlled.
(C) Storm water is treated to city standards.
(D) Rock and other debris is not tracked off-site.
(E) Driveway and approaches shall be paved with an all-weather surface, specified
by the city engineer, from at least 20 feet back from the property line to the street.
Exhibit I ‐ 65
(iv) Houses, Attached Houses and Duplexes. All driveways and parking areas must be
covered in a minimum all-weather surface, specified by the city engineer. Gravel surfacing
is not considered an all-weather surface.
(b) Striping. All parking spaces, except for stacked parking, must be striped in conformance with
the minimum parking and aisle dimensions outlined in Table 2, except parking for single-family
residences, duplexes and accessory dwelling units.
(c) Protective Curbs Around Landscaping. All perimeter and interior landscaped areas must
have continuous, cast in place or extruded protective curbs along the edges. Curbs separating
landscaped areas from parking areas may allow storm water runoff to pass through them. Tire
stops, bollards or other protective barriers may be used at the front ends of parking spaces.
Curbs may be perforated or have gaps or breaks. Trees must have adequate protection from
car doors as well as car bumpers. This provision does not apply to single-family residences,
duplexes and accessory dwelling units.
(d) Illumination. Parking lot illumination shall be provided for all parking lots containing 15 or
more parking spaces, and shall comply with the following design standards:
(i) Parking lot lighting fixtures shall be full cut-off, dark sky rated and mounted no more
than 25 feet above the ground, with lower fixtures preferable so as to maintain a human
scale;
(ii) All fixtures over 15 feet in height shall be fitted with a full cut-off shield;
(iii) Pedestrian scale lighting (light fixtures no taller than 15 feet) is encouraged in areas of
pedestrian activity. Lighting shall enable pedestrian to identify a face 45 feet away in order
to promote safety;
(iv) Parking lot lighting shall be designed to provide security lighting to all parking spaces;
(v) Lighting shall be shielded in a manner that does not disturb residential uses or pose a
hazard to passing traffic. Lighting should not be permitted to trespass onto adjacent
private parcels nor shall light source (luminaire) be visible at the property line.
(4) Stormw Water Management. Storm water runoff from parking lots is regulated by MMC Title 14, Water and
Sewers.
Exhibit I ‐ 66
(5) Parking Area Layout.
(a) Access to Parking Spaces.
(i) All parking areas, except stacked parking areas, must be designed so that a vehicle
may enter or exit without having to move another vehicle.
(ii) Parking shall be designed so that automobiles do not back out into public streets.
(b) Parking Space and Aisle Dimensions.
(i) Parking spaces and aisles must meet the minimum dimensions contained in Table 2:
Minimum Parking Space and Aisle Dimensions. Parking at any angle other than those
shown is permitted, providing the width of the stalls and aisle are adjusted by interpolation
between the specified standards.
(ii) Turning Radii. The minimum allowable inside vehicle turning radius in parking and
driveway areas shall be 20 feet unless fire or solid waste apparatus access is necessary,
in which case the minimum inside radius shall be 30.5 feet and the outside radius shall be
46 feet or as required by the fire district or solid waste division. Turning radii are not
necessarily the radii or curbs around islands and other improvements.
(iii) On dead end aisles, aisles shall extend five feet beyond the last stall to provide
adequate turnaround.
(iv) The community development director may grant a deviation from the parking space
and aisle dimensions outlined in Table 2: Minimum Parking Space and Aisle Dimensions,
whenever (a) there exists a lot with one or more structures on it constructed before the
effective date of this title, and (b) a change in use that does not involve any enlargement
of a structure is proposed for such lot, and (c) the parking space and aisle dimensions that
would be applicable as a result of the proposed change cannot be satisfied on such lot
because there is not sufficient area available on the lot that can practicably be used for
parking dimensional standards. To grant a deviation, the community development director
must make the following findings:
Exhibit I ‐ 67
(A) That the granting of the deviation will not create a safety hazard or loading of
vehicles on public streets in such a manner as to interfere with the free flow of
vehicular and pedestrian traffic within the public right-of-way.
(B) That the granting of the deviation will not create a safety hazard or any other
condition inconsistent with the objectives of this title.
Table 2: Minimum Parking Space and Aisle Dimensions
Angle Width Curb Length
1-Way
Aisle Width
2-Way
Aisle Width Stall Depth
0 degrees (parallel) 8 feet 21 feet 12 feet 22 feet 8 feet
30 degrees 8 feet, 6 inches 17 feet 12 feet 22 feet 15 feet
45 degrees 8 feet, 6 inches 12 feet 12 feet 22 feet 17 feet
60 degrees 8 feet, 6 inches 9 feet, 9 inches 16 feet 22 feet 18 feet
90 degrees 8 feet, 6 inches 8 feet, 6 inches 22 feet 22 feet 18 feet
Note: Dimensions of parking spaces for the disabled are regulated by the building code. See MMC
22C.130.050(5)(e).
(c) Pedestrian Access and Circulation. Developments must provide specially marked or paved
walkways through parking lots, as depicted in Figure(s) 1 through 4. Parking lot walkways shall
allow for access so pedestrians and wheelchairs can easily gain access from public sidewalks
and bus stops to building entrances through the use of raised concrete, or pervious pavement
sidewalks, or pedestrian paths which are physically separated from vehicle traffic and
maneuvering areas. Generally, walkways should be provided every four rows and a maximum
distance of 180 feet shall be maintained between paths. Where possible, align the pathways to
connect with major building entries or other sidewalks, pathways, and destinations. The
pathways must be universally accessible and meet ADA standards.
Figure 1 Figure 2
Exhibit I ‐ 68
Figure 3 Figure 4
(d) Location. Parking areas should be located and designed to consider impacts to the
streetscape. Except for adult facilities as defined by MMC 22A.020.020, on-site parking shall be
located at the sides and rear of buildings or complexes. For adult facilities, on-site parking shall
be located where most visible from both the streetscape and the public access to the adult
facility.
(e) Parking for Disabled Persons. The building official regulates the following disabled person
parking standards and access standards through the building code and the latest ICC/ANSI
A117.1 standards for accessible and usable buildings and facilities:
(i) Dimensions of disabled person parking spaces and access aisles;
(ii) The minimum number of disabled person parking spaces and circulation routes;
Exhibit I ‐ 69
(iii) Location of disabled person parking spaces and circulation routes;
(iv) Curb cuts and ramps including slope, width and location; and
(v) Signage and pavement markings.
(f) A portion of a standard parking space may be landscaped instead of paved, as follows:
(i) The landscaped area may be up to two feet of the front of the space as measured from
a line parallel to the direction of the bumper of a vehicle using the space. Any vehicle
overhang must be free from interference from sidewalks, landscaping, or other required
elements;
(ii) Landscaping must be ground cover plants; and
(iii) The landscaped area counts toward parking lot interior landscaping requirements and
toward any overall site landscaping requirements. However, the landscaped area does not
count toward perimeter landscaping requirements.
(g) Ingress and Egress Provisions. The layout of parking areas are reviewed for compliance with
the curb cut and access restrictions outlined in the Marysville engineering design and
development standards (EDDS).
(6) Parking Area Landscaping and Screening. All landscaping must comply with the standards of Chapter
22C.120 MMC. In addition, screening in the form of a solid masonry wall, architectural fences or dense
coniferous hedges shall be erected or planted and maintained to a height of not less than five feet where a
parking lot has a common boundary line with any residentially zoned property.
(7) Maintenance. Maintenance of all areas provided for off-street parking shall include removal and
replacement of dead and dying trees, grass and shrubs, removal of trash and weeds, and repair of traffic-
control devices, signs, light standards, fences, walls, surfacing materials, curbs, railings and inspection,
cleaning and repair of pervious surfacing materials and drainage facilities when applicable.