Ordinance 4044ORDINANCE NO.4044
AN ORDINANCE OF THE CITY OF EDMONDS,
WASHINGTON, AMENDING CHAPTER 18.30 ECDC,
ENTITLED "STORMWATER MANAGEMENT," IN ITS
ENTIRETY.
WHEREAS, the City of Edmonds is a Department of Ecology Phase II Western
Washington Municipal Stormwater Permit holder; and
WHEREAS, as a Phase II permit holder, the City is required to update its stormwater code by
December 31, 2016, to meet the minimum requirements of the 2012 Ecology Stormwater Management
Manual; and
WHEREAS, these requirements include reviewing and revising all development -related codes,
rules, and standards to incorporate and require Low Impact Development principles and best management
practices to make Low Impact Development the preferred and commonly used approach to site
development; and
WHEREAS, the goal of Low Impact Development is to infiltrate, disperse, and retain
stormwater runoff onsite to the extent feasible; NOW, THEREFORE,
THE CITY COUNCIL OF THE CITY OF EDMONDS, WASHINGTON, DO ORDAIN
AS FOLLOWS:
Section 1. Chapter 18.30 of the Edmonds Community Development Code, entitled
"Stormwater Management," is hereby amended to read as set forth in Attachment A hereto,
which is incorporated herein by this reference as if set forth in full. The existing text of chapter
18.30 ECDC shall be replaced entirely with the text shown in Attachment A.
Section 2. Severability. If any section, subsection, clause, sentence, or phrase of this
ordinance should be held invalid or unconstitutional, such decision shall not affect the validity of
the remaining portions of this ordinance.
1
Section 3. Effective Date. This ordinance, being an exercise of a power specifically
delegated to the City legislative body, is not subject to referendum and shall take effect upon the
latter of five (5) days after passage and publication of an approved summary thereof consisting
of the title and January 1, 2017.
VED:
ATTEST/AUTHE TED:
CIY CLERK, SCOT PA Y
APPROVED AS TO FORM:
OFFICE OF THE CITY ATTORNEY:
BY
JEFF TARADAY
FILED WITH THE CITY CLERK: September 30, 2016
PASSED BY THE CITY COUNCIL: October 4, 2016
PUBLISHED: October 9, 2016
EFFECTIVE DATE: January 1, 2017
ORDINANCE NO. 4044
2
SUMMARY OF ORDINANCE NO.4044
of the City of Edmonds, Washington
On the 4th day of October, 2016, the City Council of the City of Edmonds, passed
Ordinance No. 4044. A summary of the content of said ordinance, consisting of the title,
provides as follows:
AN ORDINANCE OF THE CITY OF EDMONDS,
WASHINGTON, AMENDING CHAPTER 18.30 ECDC,
ENTITLED "STORMWATER MANAGEMENT," IN ITS
ENTIRETY
The full text of this Ordinance will be mailed upon request.
DATED this 51h day of October, 2016.
C LERK, OT P SEY
3
Edmonds
Chapter 18.30 STORM WATER MANAGEMENT
Chapter 18.30
STORMWATER MANAGEMENT
Sections:
18.30.000 Purposes.
18.30.010 Definitions.
18.30.020 Authority and Regulation.
18.30.030 Applicability.
18.30.040 Exemptions.
18.30.050 Administration.
18.30.060 Requirements.
18.30.070 Exceptions, Adjustments, and Appeal.
18.30.080 Access and Covenants.
18.30.090 Post Construction Inspection and Maintenance Roles and Responsibilities.
18.30.100 Enforcement Procedures.
18.30.000 Purposes.
Page 1/23
A. To set forth standards for managing stormwater runoff from construction and development sites to minimize:
1. Degradation of surface water quality by controlling the scouring and sedimentation of creeks, streams,
wetlands, ponds, lakes, other water bodies.
2. Degradation of groundwater quality.
3. Damage to adjacent and other downstream private properties from erosion or other impacts from stormwater
runoff.
4. Damage of City -owned parcels, City roads, rights -of -way and associated infrastructure.
B. To comply with requirements in the Phase II National Pollutant Discharge Elimination System (NPDES) Municipal
Stormwater Permit as issued by the Washington State Department of Ecology (Ecology).
C. To complement site planning activities that minimize:
1. Impervious surfaces area.
2. The loss of native or non-native site vegetation.
3. The generation of stormwater runoff.
D. To make low impact development (LID) the preferred and commonly used approach to site development; to require
LID be considered at the site planning stage; and to implement LID BMPs unless they are infeasible.
E. To require that all publicly -owned and privately -owned Stormwater Treatment and Flow Control best management
practices (BMPs)/Facilities are operated, maintained and repaired in manner that conforms to this chapter.
F. To provide the authority for the City to inspect privately -owned Stormwater Treatment and Flow Control
BMPs/Facilities.
G. To provide enforcement procedures for ensuring compliance with this chapter
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18.30.010 Definitions.
For the purposes of this chapter, the following definitions shall apply:
Arterial. A road or street primarily for through traffic. The term generally includes roads or streets considered
collectors. It does not include local access roads which are generally limited to providing access to abutting property.
See also RCW 35.78.010, RCW 36.86.070, and RCW 47.05.021.
Adjustment. A variation in the application of a minimum requirement to a particular project. Adjustments provide
substantially equivalent environmental protection.
Applicant. The owning individual(s) or corporations or their representatives applying for the permits or approvals
described in this chapter.
Approval. The proposed work or completed work conforming to this chapter as approved by the public works Director
or their designee.
Best management practices (BMPs). The schedules of activities, prohibitions of practices, maintenance procedures,
and structural and/or managerial practices approved by the City that, when used singly or in combination, prevent or
reduce the release of pollutants an¢ other adverse impacts to waters of Washington State.
Bioretention. Engineered facilities that treat stormwater by passing it through a specified soil profile, and either retain
or detain the treated stormwater for flow attenuation. Refer to the 2014 Stormwater Management Manual for Western
Washington (SWMMWW), Chapter 7 of Volume V for bioretention BMP types and design specifications.
Category 1 Project Site. A project site subject to Minimum Requirements No.I through No.S. See ECDC 18.30.60.C.
Category 2 Project Site. A project site subject to Minimum Requirements No.1 through No.9. See ECDC 18.30.60.C.
Certified Erosion and Sediment Control Lead (CESCL). An individual who has current certification through an
approved erosion and sediment control training program that meets the minimum training standards established by
Ecology (see BMP C160 in the SWMMWW). 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 stormwater and, the effectiveness of erosion and sediment control measures used to control the
quality of stormwater discharges. Certification is obtained through an Ecology approved erosion and sediment control
course. Course listings are provided online at Ecology's website.
City's municipal separate storm sewer system or "MS4." A conveyance or system of conveyances (including roads
with drainage systems, municipal streets, catch basins, curbs, gutters, ditches, manmade channels, or storm drains)
that are owned or operated by the City of Edmonds, designed or used for collecting or conveying stormwater, and are
not a combined sewer nor part of a publicly owned treatment works as defined in 40 Code of Federal Regulations
(CFR) 122.2, and which is defined as "large" or "medium" or "small" or otherwise designated by Ecology pursuant to
40 CFR 122.26.
Clearing. The destruction and removal of vegetation by manual, mechanical, or chemical methods.
Commercial Agriculture. Those activities conducted on lands defined in RCW 84.34.020(2) and activities involved in
the production of crops or livestock for commercial trade. An activity ceases to be considered commercial agriculture
when the area on which it is conducted is proposed for conversion to a nonagricultural use or has lain idle for more
than five years, unless the idle land is registered in a federal or state soils conservation program, or unless the activity
is maintenance of irrigation ditches, laterals, canals, or drainage ditches related to an existing and ongoing agricultural
activity.
Common plan of development or sale. A site where multiple separate and distinct construction activities may be taking
place at different times on different schedules and/or by different contractors, but still under a single plan. Examples
include: 1) phase projects and projects with multiple filings or lots, even if the separate phases or filings/lots will be
constructed under separate contract or by separate owners (e.g., a development where lots are sold to separate
builders); 2) a development plan that may be phased over multiple years, but is still under a consistent plan for
long-term development; 3) projects in a contiguous area that may be unrelated but still under the same contract, such
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Chapter 18.30 STORM WATER MANAGEMENT
as construction of a building extension and a new parking lot at the same facility; and 4) linear projects such as roads,
pipelines, or utilities. If the project is part of a common plan of development or sale, the disturbed area of the entire
plan must be used in determine permit requirements.
Converted vegetation (areas). The change in land cover changed from native vegetation, pasture scrub/shrub, or
unmaintained non-native vegetation to lawn or landscaped areas, or where native vegetation is converted to pasture.
Creek. Is synonymous with "streams," which is defined in ECDC 23.40.320.
Detention facility. An above or below ground facility, such as a pond or tank, that temporarily stores stormwater
runoff and subsequently releases it at a slower rate than it is collected by the drainage facility system. There is little or
no infiltration of stored stormwater.
Development. Land -disturbing activities, including Class IV general forest practices that are conversions from timber
land to other uses. Creation or addition of hard surfaces, or replacement of hard surface that is not part of a routine
maintenance activity. Structural development, including construction, installation, replacement, or expansion of a
building or other structure. Subdivision, short subdivision, and binding site plans, as defined and applied in Chapter
58.17 RCW
Director. The City's Public Works and Utilities Director or a designee with an appropriate background in engineering
or another related discipline.
Discharge point. The location where a discharge leaves the municipal separate storm sewer system (MS4) through the
City's MS4 facilities/BMPs designed to infiltrate.
Ecology. The Washington State Department of Ecology.
Effective impervious surface. Those impervious surfaces that are connected via sheet flow or discrete conveyance to a
drainage system. Impervious surfaces on residential development sites are considered ineffective if: 1) the runoff is
dispersed through at least 100 feet of native vegetation in accordance with BMP T5.30 — "Full Dispersion," as
described in Chapter 5 of Volume V of the SWMMWW; 2) residential roof runoff is infiltrated in accordance with
downspout Full Infiltration Systems in BMP T5.10A in Volume III of the SWMMWW; or 3) approved continuous
runoff modeling methods indicate the entire runoff file is infiltrated.
Erodible or leachable materials. Wastes, chemicals, or other substances that measurably alter the physical or chemical
characteristics of runoff when exposed to rainfall. Examples include erodible soils that are stockpiled, uncovered
process wastes, manure, fertilizers, oily substances, ashes, kiln dust, and garbage dumpster leakage.
Erosion. The wearing away of the land surface by running water, wind, ice, or other geological agents, including such
processes as gravitational creep. Also, detachment and movement of soil or rock fragments by water, wind, ice, or
gravity. See the SWMMWW Glossary for examples of types of water erosion.
Excavation. The mechanical removal of earth material.
Exception. Relief from the application of a minimum requirement to a project.
Fill. A deposit of earth material placed by artificial means.
Groundwater. Water in a saturated zone or stratum beneath the land surface or below a water body.
Hard surface. An impervious surface, a permeable pavement, or a vegetated roof.
Highway. A main public road connecting towns and cities. In Edmonds, this includes State Route 99, State Route 524,
and portions of State Route 104, that are classified as principal arterials in the City's comprehensive transportation
plan.
Illicit discharge. Any direct or indirect non-stormwater discharge to the City's MS4, groundwaters, or a water body,
except as expressly allowed by ECDC Chapter 7.200.
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Chapter 18.30 STORM WATER MANAGEMENT
Impervious surface. A non -vegetated surface area that either prevents or retards the entry of water into the soil mantle
as under natural conditions prior to development. A non -vegetated surface area which causes water to run off the
surface in greater quantities or at an increased rate of flow from the flow present under natural conditions prior to
development. Common impervious surfaces include, but are not limited to, roof tops, walkways, patios, driveways,
parking lots or storage areas, concrete or asphalt paving, gravel roads, packed earthen materials, and oiled, macadam
or other surfaces that similarly impede the natural infiltration of stormwater. Open, uncovered retention/detention
facilities shall not be considered impervious surfaces for purposes of determining whether the thresholds for
application of minimum requirements are exceeded. Open, uncovered retention/detention facilities shall be considered
impervious surfaces for purposes of runoff modeling. Outdoor swimming pools shall be considered impervious
surfaces in all situations. In addition, lawns, landscaping, sports fields, golf courses, and other areas that have modified
runoff characteristics resulting from the addition of underdrains are to be considered impervious surfaces.
Lake. An inland body of fresh water surrounded by land.
Land disturbing activity. Any activity that results in a change in the existing soil cover (both vegetative and
non -vegetative) and/or the existing soil topography. Land -disturbing activities include but are not limited to
demolition, clearing, grading, filling, and excavation. Compaction that is associated with stabilization of structures
and road construction shall also be considered a land -disturbing activity. Vegetation maintenance practices, including
landscape maintenance and gardening, are not considered land -disturbing activity. Stormwater facility maintenance is
not considered land disturbing activity if conducted according to established standards and procedures.
Low impact development (LID). A stormwater and land use strategy that strives to mimic pre -disturbance hydrologic
processes of infiltration, filtration, storage, evaporation and transpiration by emphasizing conservation, use of on -site
features, site planning, and distributed stormwater management practices that are integrated into a project design.
LID Best Management Practices (BMPs). Distributed stormwater management practices, integrated into a project
design, that emphasize pre -disturbance hydrologic processes of infiltration, filtration, storage, evaporation and
transpiration. LID BMPs include, but are not limited to, bioretention, rain gardens, permeable pavements, roof
downspout controls, dispersion, soil quality and depth, minimal excavation foundations, vegetated roofs, and water
re -use.
LID principles. Land use management strategies that emphasize conservation, use of on -site natural features, and site
planning to minimize impervious surfaces, native vegetation loss, and stormwater runoff.
Maintenance. Repair and maintenance activities conducted on currently serviceable structures, facilities, and
equipment that involves no expansion or use beyond that previously existing and results in no significant adverse
hydrologic impact. It includes those usual activities taken to prevent a decline, lapse, or cessation in the use of
structures and systems. Those usual activities may include replacement of dysfunctional facilities, including cases
where environmental permits require replacing an existing structure with a different type structure, as long as the
functioning characteristics of the original structure are not changed. One example is the replacement of a collapsed,
fish blocking, round culvert with a new box culvert under the same span, or width, of roadway. In regard to stormwater
facilities, maintenance includes assessment to ensure ongoing proper operation, removal of built up pollutants (i.e.,
sediments), replacement of failed or failing treatment media, and other actions taken to correct defects as identified in
the maintenance standards of Chapter 4, Volume V of the SWMMWW.
Maximum extent practicable (MEP). Refers to paragraph 402(p)(3)(B)(iii) of the federal Clean Water Act which reads
as follows: Permits for discharges from municipal storm sewers shall require controls to reduce the discharge of
pollutants to the maximum extent practicable, including management practices, control techniques, and system,
design, and engineering methods, and other such provisions as the Administrator or the State determines appropriate
for the control of such pollutants.
MS4. The City's municipal separate storm sewer system.
Native vegetation. Vegetation comprised of plant species, other than noxious weeds, indigenous to the coastal region
of the Pacific Northwest which could have been reasonably expected to occur naturally on the site. Examples include
trees such as Douglas fir, western hemlock, western red cedar, alder, big -leaf maple, and vine maple; shrubs such as
willow, elderberry, salmonberry, and salal; and herbaceous plants such as sword fern, foam flower, and fireweed.
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Chapter 18.30 STORM WATER MANAGEMENT
Natural drainage systems and outfalls. The location of the channels, swales, and other non -manmade conveyance
systems as defined by the earliest documented topographic contours existing for the subject property, either from maps
or photographs, or such other means as appropriate.
Outfall. A point source as defined by 40 CFR 122.2 at the point where a discharge leaves the City's MS4 and enters a
surface receiving waterbody or surface receiving waters. Outfall does not include pipes, tunnels, or other conveyances
which connect segments of the same stream or other surface waters and are used to convey primarily surface waters
(i.e., culverts).
On -site Stormwater Management BMPs. A synonym for Low Impact Development BMPs.
Permeable pavement. Pervious concrete, porous asphalt, permeable pavers or other forms of pervious or porous
paving material intended to allow passage of water through the pavement section. It often includes an aggregate base
that provides structural support and acts as a stormwater reservoir.
Pervious Surface. Any surface material that allows stormwater to infiltrate into the ground. Examples include lawn,
landscape, pasture, native vegetation areas, and permeable pavements.
Person. Any individual, partnership, corporation, association, organization, cooperative, public or municipal
corporation, agency of the state, or City government unit, however designated.
Pollution -generating hard surface (PGHS). Those hard surfaces considered to be a significant source of pollutants in
stormwater runoff. See the listing of surfaces under pollution -generating impervious surface.
Pollution -generating impervious surface (PGIS). Those impervious surfaces considered to be a significant source of
pollutants in stormwater runoff. Such surfaces include those which are subject to: vehicular use; industrial activities
(as further defined in the glossary of the SWMMW W); storage of erodible or leachable materials, wastes, or
chemicals, and which receive direct rainfall or the run-on or blow-in of rainfall; metal roofs unless they are coated with
an inert, non -leachable material (e.g., baked -on enamel coating); or roofs that are subject to venting significant
amounts of dusts, mists, or fumes from manufacturing, commercial, or other indoor activities.
Pollution -generating pervious surfaces (PGPS). Any non -impervious surface subject to vehicular use, industrial
activities (as further defined in the glossary of the SWMMWW); or storage of erodible or leachable materials, wastes,
or chemicals, and that receive direct rainfall or run-on or blow-in of rainfall, use of pesticides and fertilizers, or loss of
soil. Typical PGPS include permeable pavement subject to vehicular use, lawns, and landscaped areas including: golf
courses, parks, cemeteries, and sports fields (natural and artificial turf).
Pre -developed condition. The native vegetation and soils that existed at a site prior to the influence of Euro-American
settlement. The pre -developed condition shall be assumed to be a forested land cover unless reasonable, historic
information is provided that indicates the site was prairie prior to settlement.
Project site. That portion of a property, properties, and/or right-of-way subject to land -disturbing activities, new hard
surfaces, or replaced hard surfaces. For projects that involve land disturbing activity on one or more parcels and land
disturbing activity in the City right-of-way, the "Project site" includes all areas of land disturbance. If the project is
part of a common development plan or sale, the disturbed area of the entire plan shall be used in determining permit
requirements.
Rain garden. A non -engineered shallow landscaped depression, with compost -amended native soils and adapted
plants. The depression is designed to pond and temporarily store stormwater runoff from adjacent areas, and to allow
stormwater to pass through the amended soil profile.
Receiving waterbody or Receiving waters. Naturally and/or reconstructed naturally occurring surface water bodies,
such as creeks, streams, rivers, lakes, wetlands, estuaries, and marine waters, or groundwater, to which a MS4
discharges.
Replaced hard surface. For structures means the removal and replacement of hard surfaces down to the foundation. For
other hard surfaces, it means the removal down to bare soil or base course and replacement.
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Chapter 18.30 STORM WATER MANAGEMENT
Replaced impervious surface. For structures, the removal and replacement of any exterior impervious surfaces down
to the foundation. For other impervious surfaces, it means the removal down to bare soil or base course and
replacement.
Roadway. Traveled hard surface portion of any public or private road or street.
Road -related project. A project that all of, or the majority of, the new or replaced hard surface consist of roadway,
shoulders, curbs, gutters, sidewalks, or walkways, either publicly or privately funded.
Runoff. Water originating from rainfall and other precipitation that is found in drainage facilities, rivers, streams,
springs, seeps, ponds, lakes and wetlands, as well as shallow ground water. It also means the portion of rainfall or
other precipitation that becomes surface flow and interflow.
Site. The area defined by the legal boundaries of a parcel or parcels of land that is (are) subject to development. For
road projects, or utility projects in the right-of-way, the length of the project site and the right-of-way boundaries
define the site.
Slope. The degree of deviation of a surface from the horizontal; measured as a numerical ratio, percent, or in degrees.
Expressed as a ratio, the first number is the horizontal distance (run) and the second is the vertical distance (rise), as
2:1. A 2:1 slope is a 50 percent slope. Expressed in degrees, the slope is the angle from the horizontal plane, with a
90-degree slope being vertical (maximum) and 45 degrees being a 1:1 or 100 percent slope.
Soil. The unconsolidated mineral and organic material on the intermediate surface of the earth that serves as a natural
medium for the growth of land plants.
Source control BMPs. A structure or operation that is intended to prevent pollutants from coming into contact with
storm water through physical separation of areas or careful management of activities that are sources of pollutants.
The SWMMWW separates source control BMPs into two types. Structural source control BMPs are physical,
structural, or mechanical devices, or facilities that are intended to prevent pollutants from entering stormwater.
Operational BMPs are non-structural practices that prevent or reduce pollutants from entering stormwater. See
Volume IV of the SWMMWW for details.
Stormwater facility. A constructed component of a stormwater drainage system, designed and constructed to perform
a particular function or multiple functions. Stormwater facilities include, but are not limited to, pipes, swales, ditches,
culverts, street gutters, detention ponds, retention ponds, constructed wetlands, infiltration devices, catch basins,
oil/water separators, and biofiltration swales.
Stormwater Management Manual for Western Washington (SWMMWW). The Washington State Department of
Ecology's 2012 (as amended in 2014) Stormwater Management Manual for Western Washington. Referred to as the
2014 SWMMWW.
Stormwater site plan. The comprehensive report containing all of the technical information and analysis necessary for
regulatory agencies to evaluate a proposed development project for compliance with stormwater requirements.
Contents of the Stormwater Site Plan will vary with the type and size of the project, and individual site characteristics.
It includes a Construction Stormwater Pollution Prevention Plan (Construction SWPPP) and a Permanent Stormwater
Control Plan (PSC Plan). Guidance on preparing a Stormwater Site Plan is contained in Chapter 3 of Volume I of the
SWMMWW.
Stormwater Treatment and Flow Control BMPs/Facilities. Detention facilities, treatment BMPs/facilities,
bioretention, vegetated roofs, and permeable pavements that help meet Minimum Requirements No.6 (Treatment),
Minimum Requirement No.7 (Flow Control), or both as described in ECDC 18.30.060.
Threshold discharge area. An on -site area that drains to either a single natural discharge location or multiple natural
discharge locations that combine within one -quarter mile downstream (as determined by the shortest flowpath). The
examples below and in Figure G.1 presented in Volume I of the SWMMWW illustrate this definition. The purpose of
this definition is to clarify how the thresholds of this code are applied to project sites with multiple discharge points.
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Chapter 18.30 STORM WATER MANAGEMENT
Example of a Site with a
Single Natural Discharge
and a Single Threshold
Discharge Area
Natural
Discharge ,
Area
THRESHOLD
Natural
Discharge
Location
Example of a Site with
Multiple Natural
Discharges and a Single
Threshold Discharge Area
Natural
Area
Page 7/23
Example of a Site with
Multiple Natural Discharges
and Multiple Threshold
Discharge Areas
NaAUral ,,, Natural
f7ischargpe., rge piEq�a
Area t Area 2
rHRESHOLD THRESHOLD,
)iSCHqRGE DISCHARGE -
AREA iti .-AREA 2
Natural it Natural
Discharge I Discharge
Location t Location
1 I
� 4 �
1 � j
.� a I•
>a
% Mlle Downstream ------------------------ -------------------
(shortest flow path) V V
Vehicular Use. Regular use of an impervious or pervious surface by motor vehicles. The following are subject to
regular vehicular use: roads, un-vegetated road shoulders, bike lanes within the traveled lane of a roadway, driveways,
parking lots, unrestricted access fire lanes, vehicular equipment storage yards, and airport runways.
The following are not considered subject to regular vehicular use: paved bicycle pathways separated from and not
subject to drainage from roads for motor vehicles, restricted access fire lanes, and infrequently used maintenance
access roads.
Waterbody. Surface waters including rivers, streams, lakes, marine waters, estuaries, and wetlands.
Waters of the state. Includes those waters defined as "waters of the United States" in 40 CFR Subpart 122.2 within the
geographic boundaries of Washington State, and "waters of the state" as defined in Chapter 90.48 RCW which
includes lakes, rivers, ponds, streams, inland waters, underground waters, salt waters and all other surface waters and
water courses within the jurisdiction of the state of Washington.
Wetlands. As defined in ECDC 23.40.005. [Ord. 4026 § 1 (Att. A), 2016].
18.30.020 Authority and Regulation.
A. The Public Works and Utilities Director shall administer this chapter and shall be referred to as the Director.
B. The Director shall have the authority to develop, implement, and enforce policies and procedures to administer and
enforce this chapter per ECDC 18.30.110 and 18.30.120, such as the Edmonds Stormwater Addendum.
C. The requirements of this chapter are minimum requirements. They do not replace, repeal, abrogate, supersede, or
affect any other more stringent requirements, rules, regulations, covenants, standards, or restrictions. Where this
chapter imposes requirements that are more protective of human health or the environment than those set forth
elsewhere, the provisions of this chapter shall prevail. When this chapter imposes requirements that are less protective
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of human health or the environment than those set forth elsewhere, the provisions of the more protective requirements
shall prevail.
D. The Director shall have the authority to impose additional requirements on a project or site to meet the purpose of
this chapter based on site -specific factors including, but not limited to, location, soil conditions, slope, and designated
use.
E. Approvals and permits granted under this chapter are not waivers of the requirements of any other laws, nor do they
indicate compliance with any other laws. Compliance is still required with all applicable federal, state and local laws
and regulations, including rules promulgated under authority of this chapter.
F. Compliance with the provisions of this chapter does not necessarily mitigate all impacts to the environment. Thus
compliance with this chapter should not be construed as mitigating all drainage water or other environmental impacts
and additional mitigation may be required to protect the environment pursuant to other applicable laws and
regulations. The primary obligation for compliance with this chapter and for preventing environmental harm on or
from property is placed upon the applicant. [Ord. 3792 § 1, 2010].
18.30.030 Applicability.
A. This chapter applies to applications submitted on or after January 1, 2017 and applications submitted prior to
January 1, 2017, which have not started construction by January 1, 2022.
B. This chapter applies to the following actions on sites that discharge to the City's MS4 or discharges to waters of
the state whether or not a City -issued permit is required:
1. Land -disturbing activity, or
2. Creation of new hard surfaces, or
3. Replacement of existing hard surfaces, or
4. Conversion of pervious surfaces, or
5. New connections to the City's MS4, or
6. Any other actions that can increase the volume or rate of stormwater runoff, or cause the generation of
pollutants, from the site.
18.30.040 Exemptions.
A. Full Exemptions. The following land uses and land -disturbing activities are exempt from the provisions of this
chapter:
1. 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.
2. Commercial agriculture practices that involve working land for production are generally exempt. However,
land conversion from timberland to agriculture and the construction of impervious surfaces are not exempt.
3. Construction of drilling sites, waste management pits, and associated access roads, and 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.
4. The following pavement maintenance practices or activities are exempt: pothole and square -cut patching,
overlaying existing asphalt or concrete pavement with asphalt or concrete without expanding the area of
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coverage, shoulder grading, reshaping/regrading drainage systems, crack sealing, resurfacing with in -kind
material without expanding the road prism, pavement preservation activities that do not expand the road
prism, and vegetation maintenance.
B. Partial Exemptions. The following land uses and land -disturbing activities are partially exempt from the provisions
of this chapter:
1. Underground utility projects that replace the ground surface with in -kind material or materials with similar
runoff characteristics are only subject to Minimum Requirement No. 2, Construction Stormwater Pollution
Prevention.
2. The following pavement maintenance practices or activities are considered development, and therefore are
not categorically exempt. The extent to which these requirements apply is explained for each circumstance.
a. Removing and replacing a paved surface to base course or a lower level, or repairing the pavement base:
If impervious surfaces are not expanded, Minimum Requirements No. 1 — No. 5 apply when the
thresholds identified for development projects in ECDC 18.30.060 are met. 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 that are
triggered when the thresholds identified for development projects in ECDC 18.30.060 are met.
c. Resurfacing by upgrading from dirt to gravel, asphalt, or concrete; or 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 that are triggered
when the thresholds identified for development projects in ECDC 18.30.060 are met.
18.30.050 Administration.
A. Application, Submittals, and Review.
1. The Director shall review all plans and all other submittals required by ECDC 18.30.050.A.3 for compliance
with this chapter when:
a. An application for a City permit is required under all other chapters of ECDC Title 18 or 19, or
b. A subdivision application is submitted per ECDC 20.75.040.
2. In all other situations when actions under ECDC 18.30.030 apply to a project site, review shall be under a
Stormwater permit.
3. All stormwater review submittals shall contain, in addition to the information required under any other
applicable City code, a Stormwater Site Plan as described in the Edmonds Stormwater Addendum (see
ECDC 18.30.060) and any other information required by the Director.
B. Inspections.
1. The Director shall inspect projects at various stages of the work to determine if they comply with the
requirements of this chapter, and enforcement actions shall be taken as necessary. These inspections will
include, but not be limited to, the following:
a. Prior to site clearing and construction to assess site erosion potential, and
b. During construction to verify proper installation and maintenance of required erosion and sediment
controls and other approved plan components, and
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c. All permanent stormwater treatment and flow control BMPs/facilities and catch basins in new
residential developments every six months until 90 percent of the lots are constructed (or when
construction is stopped and the site is fully stabilized) to identify maintenance needs and enforce
compliance with maintenance standards as needed, and
d. Upon completion of construction and prior to final approval to ensure proper installation of permanent
stormwater control facilities and verify that a maintenance plan is completed and responsibility for
maintenance is assigned for stormwater treatment and flow control BMPs/facilities, and
e. Post -Construction inspections per ECDC 18.30.090.
2. When reasonably required by the Director to accomplish the purpose of this chapter or to comply with local,
state or federal law or regulation on stormwater, special inspection or testing shall be performed by the
applicant.
C. Fees. Application, review and inspection fees as set in ECDC Chapter 15.00 shall be paid.
18.30.060 Requirements.
A. Documents. The sources of the stormwater management requirements for the City are from the following
documents:
1. Western Washington Phase HMunicipal Stormwater Permit, Appendix 1, modification date January 16,
2015
2. 2014 Stormwater Management Manual for Western Washington (SWMMWW)
3. The Edmonds Stormwater Addendum
In the event of conflicts between the various provisions, the more stringent provision shall apply.
B. Illicit Discharges and Connections. Non-stormwater illicit discharges, including spills, into the MS4,
groundwaters, or a water body from any developed or undeveloped lands are prohibited per ECDC Chapter 7.200.
C. Thresholds and Applicability
1. The thresholds outlined in this section are only applicable to ECDC 18.30.060.C. See also the Edmonds
Stormwater Addendum for supplemental information on thresholds.
a. All development shall be required to comply with Minimum Requirement No. 2.
b. Category 1 project sites shall comply with Minimum Requirements No. 1 through No. 5. Category 1
includes projects that:
Result in 2,000 square feet, or greater, of new plus replaced hard surface area, or
Have land disturbing activity of 7,000 square feet or greater.
c. Category 2 project sites shall comply with Minimum Requirements No. 1 through No. 9. Category 2
includes projects that:
i. Result in 5,000 square feet, or greater, of new plus replaced hard surface area, or
ii. Convert 0.75 acres, or more, of vegetation to lawn or landscaped areas, or
iii. Convert 2.5 acres, or more, of native vegetation to pasture.
Additional Requirements for road -related projects. For road -related projects, runoff from the new hard
surfaces (including pavement, shoulders, curbs, and sidewalks) and the converted vegetation areas shall meet
all the minimum requirements if the new hard surfaces total 5,000 square feet or more. In addition, if the new
hard surfaces total 5,000 square feet or more and total 50 percent or more of the existing hard surfaces within
the project limits, runoff from the new and replaced hard surfaces and the converted vegetation areas shall
meet all the minimum requirements. The project limits shall be defined by the length of the project and the
width of the right-of-way.
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3. New Connections to the City's MS4 when the proposed connection does not involve activity that meets the
definition of development. Sites that are not currently connected to the City's MS4 but that wish to connect
directly or indirectly to the City's MS4 may be allowed on a case -by -case basis, subject to City approval. For
sites that propose to drain greater than or equal to 2,000 square feet of hard surface area to the City's MS4,
minimum requirements and BMPs associated with stormwater flow control and/or water quality treatment
(such as those outlined in ECDC 18.30.060.13 [1] through [9]) may be required if the connection poses any
risk to downstream systems such as erosion, flooding, property damage, habitat damage, water quality
degradation, or other related impacts.
D. Minimum Technical Requirements. This section describes the minimum technical requirements for stormwater
management at development sites.
1. Minimum Requirement No. 1 — Preparation of Stormwater Site Plans
The City shall require a Stormwater Site Plan from all projects meeting the thresholds in ECDC 18.30.060.C.
Stormwater Site Plans shall use site -appropriate development principles 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 SWMMWW and the requirements in the Edmonds Stormwater
Addendum.
2. Minimum Requirement No. 2 — Construction Stormwater Pollution Prevention Plan (SWPPP)
a. Thresholds:
i. All development projects are responsible for preventing erosion and discharge of sediment and
other pollutants into receiving waters. Compliance with this minimum requirement can be
achieved for an individual site if the site is covered under Ecology's General NPDES Permit for
Stormwater Discharges Associated with Construction Activities and fully implementing the
requirements of that permit.
ii. A Construction SWPPP is required for all projects which a) result in 2,000 square feet or more
of new plus replaced hard surface area, b) where a structure with an exterior hard surface area of
at least 2,000 square feet is being demolished, c) which disturb 7,000 square feet or more of
land, or d) when the site falls within the Earth Subsidence Landslide Hazard Area, Landslide
Hazard Area or steep slope critical area. Projects that do not meet any of the above criteria are
not required to prepare a Construction SWPPP, but must consider all of the elements listed
below for Construction SWPPPs and develop controls for all Construction SWPPP elements
that pertain to the project site.
b. General Requirements:
i, 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. Each of the thirteen
elements referenced below must be considered and included in the SWPPP unless site
conditions render the element unnecessary and the exemption from that element is clearly
justified in the narrative of the SWPPP.
ii. Clearing and grading activities for developments shall be permitted only if conducted pursuant
to an approved site development plan (e.g., building permit, subdivision approval) that
establishes permitted areas of clearing, grading, cutting, and filling. 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 required by the City, shall be
delineated on the site plans and the development site.
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iii. The SWPPP shall be implemented beginning with initial land disturbance and until final
stabilization. Sediment and Erosion control BMPs shall be consistent with the BMPs contained
in Chapter 4 of Volume II of the SWMMWW.
c. Seasonal Work Limitations:
From October 1 through April 30, clearing, grading, and other soil disturbing activities may only be
authorized by the City if it can be demonstrated that silt -laden runoff will be prevented from leaving the
site through a combination of the following:
1. Site conditions including existing vegetative coverage, slope, soil type, and proximity to
receiving waters; and
Limitations on activities and the extent of disturbed areas; and
iii. Proposed erosion and sediment control measures, in accordance with ECDC 18.30.060.D.2.d
below.
Based on the information provided and/or local weather conditions, the City may expand or restrict the
seasonal limitation on site disturbance. The following activities are exempt from the seasonal clearing
and grading limitations, except for sites lying in whole or in part within an earth subsidence and landslide
hazard area as defined by ECDC 19.10.020.F:
Routine maintenance and necessary repair of erosion and sediment control BMPs,
ii. Routine maintenance of public facilities or existing utility structures that do not expose the soil
or result in the removal of the vegetative cover to soil, and
iii. Activities where there is one hundred percent infiltration of surface water runoff within the site
in approved and installed erosion and sediment control facilities.
d. Construction SWPPP Elements
i. Construction SWPPP elements are required in accordance with Chapter 2, Section 2.5.2 of
Volume I of the SWMMWW and the requirements in the Edmonds Stormivater Addendum.
3. Minimum Requirement No. 3 — Source Control of Pollution
All known, available and reasonable source control BMPs must be required for all projects approved by the
City. Source control BMPs must be selected, designed, and maintained in accordance with Volume IV of the
SWMMWW. All single family residential projects shall, at a minimum, incorporate required BMPs from
SWMMWW Volume IV, S411 — BMPs for Landscaping and Lawn/Vegetation Management.
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.
The discharge must have an identified overflow route that is safe and certain, and leads to the ultimate outfall
location (such as a receiving water or municipal drainage system). All outfalls require energy dissipation.
To demonstrate compliance with this core requirement, all projects shall submit an off -site qualitative
analysis. If an existing problem (or potential future problem after development) is identified, mitigation will
be required to prevent worsening of that problem. A quantitative analysis may be required for any project
deemed to need additional information or where the project proponent or the City determines that a
quantitative analysis is necessary to evaluate the off -site impacts or the capacity of the conveyance system.
See the Edmonds Stormwater Addendum for additional details on complying with this requirement.
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5. Minimum Requirement No. 5 — On -site Stormwater Management
a. Applicability:
On -site Stormwater Management BMPs are required in accordance with the following project
thresholds, standards, and lists to infiltrate, disperse, and retain stormwater runoff on -site to the extent
feasible without causing flooding or erosion impacts. See the SWMMWW and the Edmonds Stormwater
Addendum for additional details on On -site Stormwater Management BMP infeasibility.
b. Project Thresholds:
There are five project scenarios outlined below that determine the applicability of Minimum
Requirement No. 5 — On -site Stormwater Management. The first four scenarios apply to projects that
discharge directly or indirectly to the City's MS4. The fifth scenario applies to project discharges that do
not enter the City's MS4. Note that more than one of the five scenarios may apply to a given project:
i. Retrofit. Projects that discharge directly or indirectly to the City's MS4 and that contain
existing hard surfaces on the parcel or common plan of development that do not drain to an
approved stormwater management facility are required to provide On -site Stormwater
Management BMPs to manage a portion of those existing hard surfaces that will remain after
project completion. BMPs from List No.1 (See ECDC 18.30.060.D.5.d) shall be applied to a
minimum of 25 percent of those existing unmanaged surfaces, but to no more than the area
equal to the proposed new plus replaced hard surfaces.
Only for those existing unmanaged hard surfaces that remain after project completion,
applicants are not required to evaluate BMPs in priority order or document infeasibility for
these existing surfaces (as is required under ECDC 18.30.060.D.5.b [ii] and [iii] below).
However, if it is determined that the minimum 25 percent requirement cannot be met due to
BMP infeasibility, documentation of BMP infeasibility is required. In addition, when runoff
from exiting unmanaged hard surfaces is mixed with runoff from new plus replaced hard
surfaces, those BMPs must be selected and designed in accordance with the requirements for
management of new plus replaced hard surfaces (per sections [ii] and [iii] below). See the
SWMMWW and the Edmonds Stormwater Addendum for additional details on On -site
Stormwater Management BMP infeasibility.
ii. Category 1. Category 1 project sites that discharge directly or indirectly to the City's MS4 and
are required to comply with Minimum Requirements No. 1 through No. 5 (per ECDC
18.30.060.C) shall either:
a. Use On -site Stormwater Management BMPs from List No.l for all new plus replaced hard
surfaces and land disturbed (See ECDC 18.30.060.D.5.d); or
b. Demonstrate compliance with the LID Performance Standard (See ECDC
18.30.060.D.5.c). Projects selecting this option cannot use rain gardens. They may choose
to use bioretention BMPs as described in the SWMMWW.
iii. Category 2. Category 2 project sites that discharge directly or indirectly to the City's MS4 and
are required to comply with Minimum Requirements No. 1 through No. 9 (per ECDC
18.30.060.C) shall either:
a. Use On -site Stormwater Management BMPs from List No.2 for all new plus replaced
hard surfaces and land disturbed (See ECDC 18.30.060.D.5.e); or
b. Demonstrate compliance with the LID Performance Standard (See ECDC
18.30.060.D.5.c). Projects selecting this option cannot use rain gardens. They may choose
to use bioretention BMPs as described in the SWMMWW.
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iv. Direct Discharge Requirement. Projects that discharge directly to Puget Sound through the
City's MS4 (in accordance with the restrictions applicable to direct discharges to Puget Sound
presented in Section 2.5.7 of Volume I of the SWMMWW) do not have to achieve the LID
Performance Standard, nor consider bioretention, rain gardens, permeable pavement, or full
dispersion, but must meet the following:
a. Projects must implement BMP T5.13 (Post -Construction Soil Quality & Depth); BMPs
T5.10A Downspout Full Infiltration Systems, T5.1 OB Downspout Dispersion Systems, or
T5.1 OB Perforated Stub -out Connections; and BMP T5.11 Concentrated Flow Dispersion
or T5.12 Sheet Flow Dispersion; if feasible for all new plus replaced hard surfaces and
land disturbed. See the SWMMWW and the Edmonds StormwaterAddendum for
additional details on On -site Stormwater Management BMP infeasibility.
b. Edmonds Way specific requirements. After applying the requirements in item (a) above,
for all remaining project site runoff (e.g., from unmanaged surfaces, or from overflow
from on -site BMPs), the post -development 10-, and 100-year recurrence interval peak
flows shall not exceed, 0.25 and 0.45 cubic feet per second per acre of impervious surface
area, respectively. See the Edmonds Stormwater Addendum for additional details.
V. Projects that do not drain directly or indirectly to the City's MS4 are required to implement one
of the following:
a. Project sites may discharge to the downstream private property (e.g., projects located
above BNSF property) with approval from the downstream property owner(s).
b. Project sites may discharge runoff to an on -site system.
For sites located within earth subsidence and landslide hazard areas or their
buffers, a geotechnical design, analysis, and report by a geotechnical
engineer is required for the on -site system. On -site Stormwater Management
BMPs from List No.I in ECDC 18.30.060.D.5.d shall be evaluated for all
new plus replaced hard surfaces and land disturbed. Projects are not required
to evaluate BMPs in priority order or document infeasibility. The project
applicant may be subject to an extra permit processing fee for City review of
the geotechnical analysis. Projects are required to comply with all other
applicable City requirements, such as ECDC 19.10 (earth subsidence and
landslide hazard areas).
For sites located outside earth subsidence and landslide hazard areas or their
buffers, ECDC 18.30.060.D.5.ii and ECDC 18.30.060.D.5.iii shall be
followed to evaluate site appropriate BMP's.
c. Subject to prior approval by the City, project sites may pump on -site runoff to the City's
MS4. A quantitative downstream analysis in accordance with Minimum Requirement No.
4 and the Edmonds Stormwater Addendum will be required. If the City's MS4 does not
have adequate capacity to receive the applicant's pumped flows, the applicant is required
to install an on -site detention system to store runoff and pump it to the MS4 at an
approved rate.
c. LID Performance Standard
For projects that elect to meet the LID Performance Standard to comply with ECDC 18.30.060.D.b (ii)
and (iii), stormwater discharges shall match developed discharge durations to pre -developed durations
for the range of pre -developed discharge rates from 8 percent of the 2-year peak flow to 50 percent of the
2-year peak flow from the project site. Refer to the Standard Flow Control Requirement section in
Minimum Requirement No. 7 for information about the assignment of the pre -developed condition.
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Project sites that must also meet Minimum Requirement No. 7 shall match flow durations between 8
percent of the 2-year flow through the full 50-year flow.
d. List No.I for Category 1 project sites: On -site Stormwater Management BMPs for Projects Triggering
Minimum Requirements No. 1 through No. 5.
For projects that elect to use List No. 1 to comply with ECDC 18.30.060.D.b (ii), for each surface,
consider the BMPs in the order listed for that type of surface. Use the first BMP that is considered
feasible. No other On -site Stormwater Management BMP is necessary for that surface. Feasibility shall
be determined by evaluation against design criteria, limitations, and infeasibility criteria identified for
each BMP in the SWMMWW and the Edmonds StormwaterAddendum; and Competing Needs Criteria
listed in Chapter 5 of Volume V of the SWMMWW.
Lawn and landscaped areas:
i. Post -Construction Soil Quality and Depth in accordance with BMP T5.13 in Chapter 5 of
Volume V of the SWMMWW.
Roofs:
i. Full Dispersion in accordance with BMP T5.30 in Chapter 5 of Volume V of the SWMMWW,
or Downspout Full Infiltration Systems in accordance with BMP T5.I OA in Section 3.1.1 of
Volume III of the SWMMWW.
ii. Rain Gardens in accordance with BMP T5.14A in Chapter 5 of Volume V, or Bioretention in
accordance with Chapter 7 of Volume V of the SWMMWW. The rain garden or bioretention
facility must have a minimum horizontal projected surface area below the overflow which is at
least 5 percent of the area draining to it.
iii. Downspout Dispersion Systems in accordance with BMP TS.IOB in Section 3.1.2 of Volume
III of the SWMMWW.
iv. Perforated Stub -out Connections in accordance with BMP TS.IOC in Section 3.1.3 of Volume
III of the SWMMWW.
V. Detention vaults or pipes in accordance with the Edmonds Stormwater Addendum. The City
may waive the requirement to install a detention vault if the downstream analysis in Minimum
Requirement #4, or available City data, indicate that peak flow control is not beneficial.
Other Hard Surfaces:
Full Dispersion in accordance with BMP T5.30 in Chapter 5 of Volume V of the SWMMWW.
ii. Permeable Pavement in accordance with BMP T5.15 in Chapter 5 of Volume V of the
SWMMWW, or Rain Gardens in accordance with BMP T5.14A in Chapter 5 of Volume V, or
Bioretention in accordance with Chapter 7 of Volume V of the SWMMWW. The rain garden or
bioretention facility must have a minimum horizontal projected surface area below the
overflow which is at least 5 percent of the area draining to it.
iii. Sheet Flow Dispersion in accordance with BMP T5.12, or Concentrated Flow Dispersion in
accordance with BMP T5.11 in Chapter 5 of Volume V of the SWMMWW.
iv. Detention vaults or pipes in accordance with the Edmonds StormwaterAddendum. The City
may waive the requirement to install a detention vault if the downstream analysis in Minimum
Requirement #4, or available City data, indicate that peak flow control is not beneficial.
e. List No.2 for Category 2 project sites: On -site Stormwater Management BMPs for Projects Triggering
Minimum Requirements No. 1 through No. 9.
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For projects that elect to use List No. 2 to comply with ECDC 18.30.060.D.b (iii), for each surface,
consider the BMPs in the order listed for that type of surface. Use the first BMP that is considered
feasible. No other On -site Stormwater Management BMP is necessary for that surface. Feasibility shall
be determined by evaluation against design criteria, limitations, and infeasibility criteria identified for
each BMP in the SWMMWW; and Competing Needs Criteria listed in Chapter 5 of Volume V of the
SWMMWW.
Lawn and landscaped areas:
Roofs:
Post -Construction Soil Quality and Depth in accordance with BMP T5.13 in Chapter 5 of
Volume V of the SWMMWW.
Full Dispersion in accordance with BMP T5.30 in Chapter 5 of Volume V of the SWMMWW,
or Downspout Full Infiltration Systems in accordance with BMP T5.I OA in Section 3.1.1 of
Volume III of the SWMMWW.
ii. Bioretention (See Chapter 7 of Volume V of the SWMMWW) facilities that have a minimum
horizontally projected surface area below the overflow which is at least 5 percent of the total
surface area draining to it.
iii. Downspout Dispersion Systems in accordance with BMP TS.IOB in Section 3.1.2 of Volume
III of the SWMMWW.
iv. Perforated Stub -out Connections in accordance with BMP T5.1 OC in Section 3.1.3 of Volume
III of the SWMMWW.
Detention vaults or pipes in accordance with the Edmonds Stormwater Addendum. Note that if
the project is required to construct a flow control facility to comply with Minimum
Requirement No. 7 (per ECDC 18.30.060.D.7), a detention vault is not required to be installed
to meet Minimum Requirement No. 5. In addition, the City may waive the requirement to
install a detention vault if the downstream analysis in Minimum Requirement #4, or available
City data, indicate that peak flow control is not beneficial.
Other Hard Surfaces:
Full Dispersion in accordance with BMP T5.30 in Chapter 5 of Volume V of the SWMMWW.
ii. Permeable pavement in accordance with BMP T5.15 in Chapter 5 of Volume V of the
SWMMWW.
iii. Bioretention (See Chapter 7 of Volume V of the SWMMWW) facilities that have a minimum
horizontally projected surface area below the overflow which is at least 5 percent of the total
surface area draining to it.
iv. Sheet Flow Dispersion in accordance with BMP T5.12, or Concentrated Flow Dispersion in
accordance with BMP T5.11 in Chapter 5 of Volume V of the SWMMWW.
Detention vaults or pipes in accordance with the Edmonds Stormwater Addendum. Note that if
the project is required to construct a flow control facility to comply with Minimum
Requirement No. 7 (per ECDC 18.30.060.D.7), a detention vault is not required to be installed
to meet Minimum Requirement No. 5. In addition, the City may waive the requirement to
install a detention vault if the downstream analysis in Minimum Requirement #4, or available
City data, indicate that peak flow control is not beneficial.
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a. Project Thresholds: When assessing road -related projects against the following thresholds, only consider
those hard and pervious surfaces that are subject to this minimum requirement per ECDC 18.30.060.C.2.
For all other projects, the requirements apply to the new plus replaced hard surfaces and the converted
vegetation areas. 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 0.75 acres 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 and Facility Sizing:
Treatment -Type Thresholds in accordance with Step 2 (Oil Control), Step 4 (Phosphorus
Treatment), Step 5 (Enhanced Treatment), and Step 6 (Basic Treatment) of Chapter 2, Section
2.1, Volume V of the SWMMWW. Phosphorus treatment shall be required for projects draining
to Hall Creek and Lake Ballinger.
ii. Treatment Facility Sizing, including Water Quality Design Storm Volume, Water Quality
Design Flow Rate, and Downstream Facilities, of Chapter 2, Section 2.5.6, Volume I of the
SWMMWW.
c. Treatment Facility Selection, Design, and Maintenance
Stormwater treatment facilities shall be:
Selected in accordance with the process identified in Chapter 4 of Volume I, and Chapter 2 of
Volume V of the SWMMWW,
Designed in accordance with the design criteria in Volume V of the SWMMWW, and
iii. Maintained in accordance with the maintenance schedule in Volume V of the SWMMWW.
d. Additional Requirements
The discharge of untreated stormwater from pollution -generating surfaces to ground water will not
be authorized by the City. All associated runoff must be treated using On -site Stormwater
Management BMPs designed to provide the required level of treatment in accordance with Chapter
5, Volume V and Chapter 7, Volume V of the SWMMWW; or by infiltration through soils meeting
the soil suitability criteria in Chapter 3 of Volume III of the SWMMWW.
7. Minimum Requirement No. 7 — Flow Control
a. Applicability: Flow control is required on projects meeting the thresholds summarized below to reduce
the impacts of stormwater runoff from hard surfaces and land cover conversions. Flow control in
accordance with Minimum Requirement No. 7 is not required for projects that discharge directly to, or
indirectly through the City's MS4 to Puget Sound (other minimum requirements may still apply). See
ECDC 18.30.060.D.5.b.iv and Section 2.5.7 of Volume I of the SWMMWW for additional restrictions
applicable to direct discharges to Puget Sound.
If the discharge drains 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.
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b. Thresholds: When assessing road -related projects against the following thresholds, only consider only
those impervious, hard, and pervious surfaces that are subject to this minimum requirement per ECDC
18.30.060.C.2. For all other projects, the requirements apply to the new plus replaced hard surfaces and
the converted vegetation areas. 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
threshold discharge area, or
ii. Projects that convert 0.75 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).
c_ Standard Flow Control Requirement (applies to discharges directly or indirectly to the City's MS4,
except for projects that meet the direct discharge requirements outlined in "a" above): Stormwater
discharges shall match developed discharge durations to pre -developed durations for the range of
pre -developed discharge rates from 50 percent of the 2-year peak flow up to the full 50-year peak flow.
The pre -developed condition to be matched shall be a forested land cover unless reasonable, historic
information is available that indicates the site was prairie prior to settlement (modeled as "pasture" in the
Western Washington Hydrology Model). This standard requirement is waived for sites that will reliably
infiltrate all the runoff from hard surfaces and converted vegetation areas.
d. Additional Requirement: Flow Control BMPs shall be selected, designed, and maintained in accordance
with Volume III of the SWMMWW or an approved equivalent.
8. Minimum Requirement No. 8 — Wetlands Protection
a. Applicability: The requirements below 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 No. 6 — Runoff Treatment, and
Minimum Requirement No. 7 — Flow Control shall also be applied to determine the applicability of this
requirement to discharges to wetlands.
c. Standard Requirement: Projects shall comply with Guide Sheets No. 1 through No. 3 in Appendix I-D of
the SWMMWW. The hydrologic analysis shall use the existing land cover condition to determine the
existing hydrologic conditions unless directed otherwise by a regulatory agency with jurisdiction.
d. Additional Requirements: Stormwater treatment and flow control facilities shall not be built within a
natural vegetated buffer, except for:
Necessary conveyance systems as approved by the City; or
ii. As allowed in wetlands approved for hydrologic modification or treatment in accordance with
Guide Sheet 2 in Appendix I-D of the SWMMWW.
An adopted and implemented basin plan prepared in accordance with the provisions of Section 7 of
Appendix 1 of the Phase II NPDES Municipal Stormwater Permit.
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Edmonds
Chapter 18.30 STORM WATER MANAGEMENT
9. Minimum Requirement No. 9 — Operation and Maintenance
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An operation and maintenance manual that is consistent with the provisions in Volume I and Volume V of the
SWMMWW is required for proposed Stormwater Treatment and Flow Control BMPs/facilities. 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.
18.30.070 Exceptions, Adjustments, and Appeals.
A. Exceptions.
1. The Director may approve a request for an exception to the minimum requirements of this chapter following
legal public notice of an application for an exception and of the Director's decision on the application. All
legal public notice related to this request for an exception shall be in the manner prescribed in ECDC
20.03.002 and the applicant shall pay all costs to publish the legal public notices required by this provision.
The Director shall provide and keep written findings of fact of the decision.
2. The approval of the exception shall only be granted when the applicant demonstrates that the requirement
would cause a severe and unexpected economic hardship. To determine whether the requirement imposes a
severe and unexpected economic hardship on the project applicant, the applicant must document for City
review and approval, all of the following, at a minimum:
a. The current, pre -project use of the site; and
b. How application of the requirement(s) for which an exception is being requested restricts the proposed
use of the site compared to the restrictions that existed prior to adoption of this chapter; and
c. The possible remaining uses of the site if the exception were not granted; and
d. The possible uses of the site that would have been allowed prior to the adoption of this chapter; and
e. A comparison of the estimated amount and percentage of value loss as a result of the requirements versus
the estimated amount and percentage of value loss as a result of requirements that existed prior to
adoption of the requirements of this chapter; and
f. The feasibility of the applicant to alter the project to apply the requirements of this chapter.
3. Any exception must meet the following criteria:
a. The exception will not increase risk to the public health and welfare, nor be injurious to other properties
in the vicinity and/or downstream, and to the quality of waters of the state; and
b. The exception is the least possible exception that could be granted to comply with the intent of the
minimum requirements.
4. An exception to the requirements shall only be granted to the extent necessary to provide relief from the
economic hardship as determined by the Director, to alleviate the harm or threat of harm to the degree that
compliance with the requirement becomes technically feasible, or to perform the emergency work that the
Director determines is warranted.
5. The Director may require an applicant to provide additional information at the applicant's expense, including
(but not limited to) an engineer's report or analysis.
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Edmonds
Chapter 18.30 STORM WATER MANAGEMENT
Page 20/23
6. When an exception is granted, the Director may impose new or additional requirements to offset or mitigate
harm or the threat of harm that may be caused by granting the exception, or that would have been prevented
if the exception had not been granted.
B. Adjustments.
1. The Director may approve a request for adjustments to the requirements of this chapter when the Director
finds that:
a. The adjustment provides substantially equivalent environmental protection; and
b. The objectives of safety, function, environmental protection, and facility maintenance are met, based on
sound engineering practices.
During construction, the Director may require, or the applicant may request, that the construction of drainage
control facilities and associated project designs be adjusted if physical conditions are discovered on the site
that are inconsistent with the assumptions on which the approval was based, including (but not limited to)
unexpected soil or water conditions, weather -generated problems, or changes in the design of the improved
areas; and
A request by the applicant for an adjustment shall be submitted to the Director for review and approval prior
to implementation. The request shall be in writing and shall provide facts substantiating the requirements of
subsection (C)(1) of this section, and if made during construction, the factors in subsection (C)(2) of this
section. Any such modifications made during the construction of drainage control facilities shall be included
with the final approved drainage control plan.
C. Appeal.
1. The Director's decision on an application for an exception or adjustment may appeal to the hearing examiner
in accordance with a Type II appeal process in ECDC Chapter 20.06.
2. The applicant shall carry the burden of proof.
3. The decision of the hearing examiner is appealable to superior court in accordance with Chapter 36.70C
RCW. [Ord. 3792 § 1, 20101.
18.30.080 Access and Covenants.
A. Access. Proper ingress and egress shall be provided to the City to inspect or perform any duty imposed upon the
City by this Title. The City shall notify the responsible party in writing of a failure to provide access. If the responsible
party fails to respond within seven days from the receipt of notification, the City may order the work required
completed or otherwise address the cause of improper access. The obligation for the payment of all cost that may be
incurred or expended by the City in causing such work to be done shall be imposed on the person holding title to the
subject property
B. Covenants. Maintenance covenants shall be required for each site/lot that will be maintained by a private entity
such as an individual, corporation, or homeowner's association. The maintenance covenant shall address or append
requirements and responsibilities for long-term management and maintenance the applicable BMP(s). Maintenance
covenants shall be as specified in City Engineering Division documents or approved by the Director, and recorded
with Snohomish County and on all proper deeds [Ord. 3792 § 1, 2010].
18.30.090 Post Construction Inspection and Maintenance Roles and Responsibilities.
Proper construction inspection and maintenance of stormwater facilities is essential for the protection of the City's
MS4 and the environment.
A. Stormwater Maintenance and Inspection Standards. Stormwater facilities shall be inspected and maintained per the
requirements of Volume I and Volume V of the SWMMWW. For systems which do not have a maintenance standard,
the owner shall develop a standard based on guidelines from the manufacturer, designer, or a registered professional
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Edmonds Page 21/23
Chapter 18.30 STORM WATER MANAGEMENT
engineer and submit the standards to the Director for approval. The purpose of the maintenance standard is to
determine if maintenance is required. The maintenance standard is not a measure of the facility's required condition at
all times between inspections. Exceeding the maintenance standard between inspections is not a violation of this
chapter.
B. Ownership. Stormwater facilities are either privately or publicly owned and maintained. All stormwater facilities
that serve private property are private, unless an agreement between the property owner and the City states otherwise.
Stormwater facilities that are privately owned by a homeowner's association or similar organization also are private.
The City may offer an incentive program to owners to support the proper maintenance of private storm drainage
facilities.
C. Public Stormwater Facilities. The City shall be responsible for operating, maintaining, repairing, and replacing
public stormwater facilities as funded through the Stormwater Utility.
D. Maintenance and Inspection of Permanent Facilities. All privately owned storm drainage facilities or controls shall
be maintained by the owner, or the homeowner or owner association ("owner") if one is established as part of a
residential or commercial development. All private storm drainage facilities shall be regularly inspected to ensure
proper operation and shall monitor the facility or control as required or as set forth in the SWMMWW. The Owner
shall maintain records of inspection and maintenance, disposal receipts, and monitoring results. The records shall
catalog the action taken, the person who took it, the date said action was taken, how it was done, and any problems
encountered or follow-up actions required. The records shall be made available to the City upon request. The Owner
shall maintain a copy of the Stormwater Operations and Maintenance Manual (if required) on site, and shall make
reference to such document in real property records filed with Snohomish County, so others who acquire real property
served by the privately owned storm drainage facilities or controls are notified of their obligation to maintain such
facilities or controls.
E. City Inspection of private stormwater facilities. The City shall have the authority to periodically inspect private
stormwater facilities, including low impact development stormwater facilities, for compliance with this chapter.
F. Right of Entry. An authorized representative of the City may enter private property at all reasonable times to
conduct inspections, tests or to carry out other duties imposed by the a state or Federal program provided that the City
makes a good faith effort to notify the property owner or person responsible for the premises prior to entering and
presents proper credentials to that person. If entry is refused or cannot be obtained, the Director shall have recourse to
every remedy provided by law to secure entry, including but not limited to, obtaining an administrative warrant for
entry.
G. Right of Entry for Illicit Discharge. In the event of an illicit discharge from a privately -owned stormwater facility
caused by improper maintenance or operation or other circumstance, the provisions of ECC 7.200 shall apply.
H. Maintenance Responsibilities. Upon written notice by the City, a private stormwater facility shall be promptly
repaired and/or brought up to applicable standards by the property owner or the person responsible for said facility. If
a private stormwater facility serves multiple lots and the responsibility for maintenance has not been specified on a
recorded subdivision plat, short plat, or other legal document, maintenance, operation and repair responsibility shall
rest with the homeowners' association, if one exists, or otherwise with the properties served by the facility, or finally,
with the owners of the property on which the facilities are located.
1. Disposal of Waste from Maintenance Activities. Disposal of waste from maintenance activities shall be conducted
in accordance with the minimum Functional Standards for Solid Waste Handling, Chapter 173-304 WAC, guidelines
for disposal of waste materials from storm water maintenance activities, and where appropriate, the Dangerous Waste
Regulations, Chapter 173-303 WAC.
18.30.100 Enforcement Procedures.
A. General enforcement action shall be in accordance with this chapter whenever a person has violated any provision
of this chapter. The choice of enforcement action is at the discretion of the City.
FINAL Version: August 23, 2016
Edmonds
Chapter 18.30 STORM WATER MANAGEMENT
Page 22/23
B. Civil Penalties Adopted. ECDC Chapter 20.110 enforcement procedures are herein adopted in full, as modified in
this chapter, with the proviso that repeat offenders or violations deemed an immediate public hazard shall be subject to
compliance and appeal timelines as deemed appropriate by the Director based on the specific nature of the violation.
C. Maintenance Orders. The Director shall have the authority to issue to an owner or person an order to maintain or
repair a component of a stormwater facility or BMP to bring it into compliance with this chapter, the SWMMW W, the
Edmonds Stormwater Addendum, and the Edmonds Community Development Code. The order shall include:
1. A description of the specific nature, extent and time of the violation and the damage or potential damage that
reasonably might occur;
2. A notice that the violation or the potential violation cease and desist and, in appropriate cases, the specific
corrective actions to be taken; and
3. A reasonable time to comply, depending on the circumstances.
D. Civil Penalty. A person who fails to comply with the requirements of this chapter, who fails to conform to an
approval or order issued, who undertakes development without first obtaining approval, or who fails to comply with a
stop work order issued under these regulations shall be subject to a civil penalty levied in accordance with the
provisions of ECDC Chapter 20.110; provided, however, that the appeal process shall commence with a notice of
violation as provided in ECDC 20.110.040.13.
1. Civil penalties for code violations shall be imposed in accordance with the provisions of ECDC Chapter
20.110; provided, however, that in addition to the penalties set forth in that chapter, the hearing examiner is
authorized to levy a penalty of up to twenty thousand dollars ($20,000) per occurrence based upon an
assessment of the following factors. Where such factors are present, the hearing examiner is authorized to
levy such penalty after taking into consideration the full impact of the violation and any mitigating
circumstances (see subsection (2) below):
a. The violation created a risk to public health and the significance of the risk.
b. The violation damaged the environment and the significance of the damage.
c. The violation caused damage to public and private property and the significance of such damage.
d. A history of similar violations, if any.
e. The economic benefit of the violations, if any, to the person or entity responsible for the violations.
2. Mitigating circumstances which may be used to offset or reduce the time resulting from the application of the
preceding factors are limited to:
a. Full compliance with a voluntary compliance agreement and no history of similar violations.
b. Full compliance with a voluntary compliance agreement and a history of one or two similar violations
(lesser reduction).
c. A "voluntary compliance agreement" is defined as a legally binding agreement entered into between the
City and the alleged violators, by which the violator(s) acknowledge the existence of the violation, waive
all appeal rights, and agree to and do pay a fine in an amount stipulated to between the violator and the
City.
3. If the violation(s) are not corrected as ordered, or a voluntary compliance agreement is not entered into within
that time period and no appeal is filed, the penalty for the next 15-day period shall be 150 percent of the
initial penalties, and the penalties for the next 15-day period shall be 200 percent of the initial penalties. The
intent of this subsection is to increase penalties beyond the maximum penalties stated as an additional means
to achieve timely compliance.
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Edmonds
Chapter 18.30 STORM WATER MANAGEMENT
Page 23/23
4. Unless otherwise provided in a voluntary compliance agreement, civil penalties shall be paid within 30 days
of service of the notice and order or stop work order if not appealed. Payment of the civil penalties assessed
under this chapter does not relieve a person found to be responsible for a code violation of his or her duty to
correct the violation or to pay any and all civil penalties or other cost assessments issued pursuant to this
chapter.
5. The City may suspend immediate payment of civil penalties if the person responsible for a code violation has
entered into a voluntary compliance agreement. Penalties shall begin to accrue again pursuant to the terms of
the voluntary compliance agreement if any necessary permits applied for are denied, canceled or not
pursued, if corrective action identified in the voluntary compliance agreement is not completed as specified,
or if the property is allowed to return to a condition similar to that condition which gave rise to the voluntary
compliance agreement; provided, however, that additional penalties shall not be imposed until additional
notice and opportunity for hearing have been provided in accordance with ECDC Chapter 20.110.
6. Civil penalties assessed create joint and several personal obligations in all persons responsible for a code
violation.
E. The determination of the hearing examiner issued in accordance with ECDC Chapter 20.110 shall be appealable to
the Snohomish County superior court in accordance with the provisions of Chapter 36.70C RCW.
F. The remedies provided for in this section shall not be exclusive. The City may also use other civil and
administrative remedies available to it, including but not limited to the remedies provided in ECDC Title 19 and the
state building and dangerous buildings codes
FINAL Version: August 23, 2016
Everett Daily Herald
Affidavit of Publication
State of Washington }
County of Snohomish } ss
Kathleen Landis being first duly sworn, upon
oath deposes and says: that he/she is the legal
representative of the Everett Daily Herald a
daily newspaper. The said newspaper is a legal
newspaper by order of the superior court in the
county in which it is published and is now and
has been for more than six months prior to the
date of the first publication of the Notice
hereinafter referred to, published in the English
language continually as a daily newspaper in
Snohomish County, Washington and is and
always has been printed in whole or part in the
Everett Daily Herald and is of general
circulation in said County, and is a legal
newspaper, in accordance with the Chapter 99
of the Laws of 1921, as amended by Chapter
213, Laws of 1941, and approved as a legal
newspaper by order of the Superior Court of
Snohomish County, State of Washington, by
order dated June 16, 1941, and that the annexed
is a true copy of EDH725864 ORD #4044 as it
was published in the regular and entire issue of
said paper and not as a supplement form thereof
for a period of 1 issue(s), such publication
commencing on 10/09/2016 and ending on
10/09/2016 and that said newspaper was
regularly distributed to its subscribers during all
of said period.
The amount of the fee for such publication is
$24.08.
Subscribed and sworn before me on this
day of C'Q
Notary Public in and for the State of
Washington.
City of Edmonds - LEGAL ADS 114101416
RECEIVED
(.l (; i :'�. 13 ? 01 Fi
EDMONDSCITY CLERK
DEBRA ANN GRIGG
Notary Public
State of Washington
My Commission Expires
f� October 31, 2017
ORDINANCE SUMMARY 4-
of She City of Edmonds. WasNrglon
On the 4th day al ❑ctobor, 2010. the City Godnol al 1he.CIly P1
Edrrrond8, pass ad the lot lows ng Ordinance, the 5t mmary of She
emntent al said ordinance consi$lfna of Illle is provided as follails:
OFiDINANE NO.4044
AN ORDINANCE OF THE CITY OF: EDMONDS.
WASHINGTON, AMENDING CHAPTER 18.30 ECDC,
ENTITLED "STORMWATER MANAGEMENT; IN ITS
ENTIRETY
The full text of this Ordinance will be mailed upon request.
DATED this 5Ih day of October, 2016.
CITY CLERK, SCOTT PASSEY
UBLISH: October 9, 2016 EDH72586�