ORD 2005-10 SURFACE AND STORMWATER MANAGEMENT
Ordinance #2005-10
Stormwater Ordinance
November 22, 2005
ORDINANCE 2005-10
An Ordinance of the City of Bainbridge Island, relating to
Surface and Stonnwater Management; amending Chapter
15.20 of the Bainbridge Island Municipal Code.
WHEREAS, the City Council wishes to enact standards for surface and
stonnwater management consistent with Department of Ecology guidelines, and
WHEREAS, stonnwater pollution is a problem associated with land utilization
and development and the common occurrence of potential pollutants such as pesticides,
fertilizers, petroleum products, pet wastes and numerous others, and
WHEREAS, land utilization and development is also known to increase both
the volume and duration of peak flows, and the resulting erosion, scouring, and
deposition of sediment affect the ecological balance in the stream, and
WHEREAS, sedimentation and stormwater pollution cause diversity of species
to decrease and allows more tolerant (and usually less desirable) species to remain, and
WHEREAS, stonnwater pollution can cause or contribute to closures of
shellfish beds and swimming beaches and other restrictions on public use ofthe waters
within Bainbridge Island, and
WHEREAS, an expanding population and increased development of land have
led to water quality degradation through discharge of nutrients, metals, oil and grease,
toxic materials, and other detrimental substances including without limitation, insect
and weed control compounds, and
WHEREAS, an expanding population and increased development of land have
increased drainage and stonn and surface water runoff problems within the City; and
safety hazards to both lives and property posed by uncontrolled water runoff on streets
and highways, and
WHEREAS, continuation of present stonnwater management practices, to the
extent that they exist, will lead to water quality degradation, erosion, property damage,
and endanger the health and safety of the inhabitants of the City, and
WHEREAS, in the future such problems and dangers will be reduced or
avoided if existing properties and future developers, both private and public, provide
for st0l111water quality and quality controls, and
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Ordinance #2005-10
Stormwater Ordinance
November 22, 2005
WHEREAS, stonTIwater quality and quality control can be achieved when land
is developed or redeveloped by implementing appropriate and approved best
management practices (BMPs), and
WHEREAS, best management practices can be expected to perform as
intended only when properly designed, constructed and maintained; now therefore,
THE CITY COUNCIL OF THE CITY OF BAINBRIDGE ISLAND, WASHINGTON, DO
ORDAIN AS FOLLOWS:
Section 1.
follows:
Section 15.20.020 of the Bainbridge Island Municipal Code is amended as
15.20.020
Definitions
1. "Manual" means the manual adopted by reference and prepared by the Washington State
Department of Ecology, dated February, 2005, Stormwater Management Manual for
Western Washington, Publication Number 05-10-029 through 05-10-033.
Section 2.
follows.
Section 15.20.030 of the Bainbridge Island Municipal Code is amended as
15.20.030
General provisions.
A. Procedures. The Department of Public Works/Engineering Department is authorized to
adopt written procedures for the purpose of carrying out the provisions of this Chapter.
Prior to fulfilling the requirements of this Chapter, the Administrator or assigns shall not
grant any approval or pernlission to conduct a regulated activity, including but not limited
to, the following:
1. Building Pernlits, Commercial or Residential;
2. Comprehensive Plan Amendments;
3. Conditional Use Permits;
4. Final Plats (Short/Long/Large lot);
5. Forest Practices;
6. Grading or Clearing Permits;
7. Planned Unit Developments;
8. Plats;
a. Subdivide, preliminary and final (Short/Long/Large lot);
9. Preliminary Plats (short, long, large lot);
10. Reasonable Use Exceptions;
11. Right of Way Permits;
12. Shoreline substantial development pernlits;
13. Shoreline Variance/Shoreline Conditional Use Permits
14. Site Plan Reviews;
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Ordinance #2005-10
Stormwater Ordinance
November 22, 2005
15. Variances;
16. Zone reclassification (rezones); or
17. Any subsequently adopted permit or required approval not expressly exempted by
this chapter.
B. The following agencies may also require a drainage review to assess a site's impact. Any
requirements imposed by these agencies are separate from the City mandates. It is the
applicant's sole responsibility to resolve any conflicting issues that may arise from
submittal reviews.
1. U.S. Anny Corps of Engineers;
2. Washington State Department of Natural Resources;
3. Bremerton Kitsap County Health District;
4. Washington State Department of Ecology: General Permit is required for sites
that disturb one acre or more;
5. Washington State Department ofFish and Wildlife;
6. Washington State Department of Transportation.
Section 3.
follows:
Section 15.20.040 of the Bainbridge Island Municipal Code is amended as
15.20.040 Regulated activities and allowed activities
A. Regulated Activities. Consistent with the minimum requirements contained in the
Manual, the Administrator shall approve or disapprove the following activities, unless
exempted the Manual, Vol. I, Section 2.8:
1. New Development
a) Land disturbing activities;
b) Structural development, including construction; installation or expansion
of an existing building or other structure;
c) Creation of new impervious surfaces greater than 800 square feet;
d) Class IV General Forest Practices that are conversions from timber land
to other uses; and
e) Subdivision, short subdivision and binding site plans, as defined in
Chapter 58.17.020 RCW.
2. Redevelopment
a) On an already developed site, the creation or addition of impervious
surfaces; structural development including construction, installation or
expansion of a building or other structure; any land disturbing activity,
and/or replacement of impervious surface (that is not part of a routine
maintenance activity) and land disturbing activities associated with
structural or impervious redevelopment.
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Ordinance #2005-10
Storrnwater Ordinance
November 22, 2005
Section 4.
follows:
Section 15.20.050 of the Bainbridge Island Municipal Code is amended as
15.20.050 General Requirements.
A. Stormwater Management Manual Adopted. The February 2005 edition of Washington
State Department of Ecology's Stornlwater Management Manual for W estern Washington
is hereby adopted by reference and is hereinafter referred to as the Manual; provided that
certain provisions of the Manual are amended as stated in BIMC 15.20.060.
B. Illicit discharges. Illicit discharges to stormwater drainage systems are prohibited.
Concrete, concrete by-products, vehicle fluids, paint, chemicals or other polluting matter
shall never be pernlitted to discharge from the parcel or construction site to the natural or
constructed drainage system of the City, to Puget Sound, or to adjacent properties.
Pollution ofthe natural and constructed drainage system of the City is incompatible with
RCW 90.48 and is punishable by fines.
Section 5.
follows:
Section 15.20.060 of the Bainbridge Island Municipal Code is amended as
15.20.060
Approval Standards.
A. In Volume J, Section 2.3 of the Manual, "Definitions Related to Minimum
Requirements", the definition of "Threshold Discharge Area" is not adopted.
B. In Volume ]I, Section 2.5.6 of the Manual, "Minimum Requirement #6 Runoff
Treatment", and Section 2.5.7, "Minimum Requirement #7 Flow Control" and Section
4.2, "BMP and Facility Selection Process", references to Threshold Discharge Area are
deleted.
C. In Volume I, Section 2.3 of the Manual, "Definitions Related to Minimum
Requirements", the definition for "pollution-generating impervious surface" is amended
to exclude all paved bike lanes, either separated from or connected to driving surfaces.
D. In Volume J, Section 2.4.1 of the Manual, "New Development" is amended to read as
follows:
All new development that shall be required to comply with Minimum Requirement #2. In
addition, new development that exceeds certain thresholds shall be required to comply
with additional Minimum Requirements as follows. The following new development
shall comply with Minimum Requirements #1 through #5:
1. Creates or adds 800 square feet, or greater, of new, replaced, or new plus replaced
impervious surface area, or
2. Has land disturbing activity of 7,000 square feet or greater,
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Ordinance #2005-10
Stormwater Ordinance
November 22, 2005
The following new development shall comply with Minimum Requirements #1 through
10:
1. Creates or adds 5,000 square feet, or more, of new impervious surface area, or
2. . Converts % acres, or more, of native vegetation to lawn or landscaped areas, or
3. Converts 2.5 acres, or more, of native vegetation to pasture.
E. In Volume I, Section 2.4.2 of the Manual, "Redevelopment", is amended to read as
follows:
All redevelopment shall be required to comply with Minimum Requirement #2. In
addition, all redevelopment that exceeds certain thresholds shall be required to comply
with additional Minimum Requirements as follows.
The following redevelopment shall comply with Minimum Requirements #1 through #5
for the new and replaced impervious surfaces and the land disturbed:
1. The new, replaced, or total of new plus replaced impervious surfaces is 800
square feet or more, or
2. 7,000 square feet or more ofland disturbing activities.
The following redevelopment shall comply with Minimum Requirements #1 through 10
for the new impervious surfaces and convelied pervious areas:
1. Adds 5,000 square feet or more of new impervious surfaces or,
2. Converts % acres, or more, of native vegetation to lawn or landscaped areas, or
3. Converts 2.5 acres, or more, of native vegetation to pasture.
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 stomlwater treatment
facilities must be sized for the entire flow that is directed to them.
The Administrator may allow the Minimum Requirements 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.
Additional Requirements for the Proiect Site
For road-related projects, runoff from the replaced and new impervious surfaces
(including pavement, shoulders, curbs, and sidewalks) shall meet all the Minimum
Requirements if the new impervious surfaces total 5,000 square feet or more and total
50% or more of the existing impervious 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.
Other types ofredevelopment projects shall comply with all the Minimum Requirements
for the new and replaced impervious surfaces if the total of new plus replaced impervious
surfaces is 5,000 square feet or more, and the valuation of proposed improvements-
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Ordinance #2005-10
Stormwater Ordinance
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including interior improvements ~ exceeds 50% of the assessed value of the existing site
improvements.
F. In Volume 1, Section 2.5.10 of the Manual, "Minimum Requirement #10: Operation and
Maintenance", is amended to read as follows:
An operation and maintenance manual that is consistent with BIMC 15.21 and the
provisions in Volume V of this manual shall be provided for all proposed stonnwater
facilities and BMPs, and the party (or parties) responsible for maintenance and operation
shall be identified. At private facilities, a copy of the manual shall be retained onsite 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 Public Works
Department A log of maintenance activity that indicates what actions were taken shall be
kept and be available for inspection by the Administrator.
G. In Volume I, Section 2.6.1 of the Manual, "Financial Liability/Bonding", is not adopted.
H. In Volume I, Section 2.6.2 of the Manual, "Optional Guidance # 2 Off Site Analysis and
Mitigation" and Volume 1, Section 3.1.3, "Perform an Offsite Analysis" are adopted by
reference and established for projects creating 5,000 square feet or more of impervious
area.
1. In Volume 1, Section 2.6.2 of the Manual, "Optional Guidance #2: Off Site Analysis and
Mitigation Development", is amended to read as follows.
Development projects that discharge stormwater offsite shall submit an offsite analysis
report that assesses the potential off-site water quality, erosion, slope stability, and
drainage impacts associated with the project and that proposes appropriate mitigation of
those impacts. An initial qualitative analysis shall extend downstream for the entire flow
path from the project site to the receiving water or up to one mile, whichever is less.
If a receiving water is within one-quarter mile, the analysis shall extend within the
receiving water to one-quarter mile from the project site. The analysis shall extend one-
quarter mile beyond any improvements proposed as mitigation. The analysis must extend
upstream to a point where any backwater effects created by the project cease. Upon
review of the qualitative analysis, the local administrator may require that a quantitative
analysis be perfonned.
The existing or potential impacts to be evaluated and mitigated shall include:
1. Conveyance system capacity problems;
2. Localized flooding;
3. Upland erosion impacts, including landslide hazards;
4. Stream channel erosion at the outfall location;
5. Violations of surface water quality standards as identified in a Basin Plan or a
TMDL (Water Clean-up Plan); or violations of ground water standards in a
wellhead protection area.
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Ordinance #2005-10
Stormwater Ordinance
November 22,2005
Projects shall be required to initially submit, with the permit application, a qualitative
analysis of each downstream system leaving a site. The analysis should accomplish four
tasks:
Task 1 - Define and map the study area
Submission of a site map showing property lines; a topographic map (at a minimum a USGS
I :24000 Quadrangle Topographic map) showing site boundaries, study area boundaries,
downstream flowpath, and potential/existing problems.
Task 2 - Review all available information on the study area
This should include all available basin plans, ground water management area plans, drainage
studies, floodplain!Jloodway FEMA maps, wetlands inventory maps, Critical Areas maps, stream
habitat reports, salmon distribution reports, etc.
Task 3 - Field inspect the study area
The design engineer should physically inspect the existing on- and offsite drainage systems of
the study area for each discharge location for existing or potential problems and drainage
features. An initial inspection and investigation should include:
1. Investigate problems reported or observed during the resource review;
2. Locate existing/potential constrictions or capacity deficiencies in the drainage system;
3. Identify existing/potential flooding problems;
4. Identify existing/potential overtopping, scouring, bank sloughing, or sedimentation;
5. Identify significant destruction of aquatic habitat (e.g., siltation, stream incision);
6. Collect qualitative data on features such as land use, impervious surface, topography,
soils, presence of streams, wetlands;
7. Collect infonnation on pipe sizes, channel characteristics, drainage structures;
8. Verify tributary drainage areas identified in Task 1;
9. Contact the local government office with drainage review authority, neighboring property
owners, and residents about drainage problems; and
10. Note date and weather at time of inspection.
Task 4 - Describe the drainage system, and its existing and predicted problems
For each drainage system component (e.g., pipe, culvert, bridges, outfalls, ponds, vaults) the
following should be covered in the analysis: location, physical description, problems, and field
observations. All existing or potential problems (e.g., ponding water, erosion) identified in tasks
2 and 3 above should be described. The descriptions should be used to determine whether
adequate mitigation can be identified, or whether more detailed quantitative analysis is
necessary. The following information should be provided for each existing or potential problem:
1. Magnitude of or damage caused by the problem;
2. General frequency and duration;
3. Return frequency of storm or flow when the problem occurs (may require quantitative
analysis);
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4. Water elevation when the problem occurs;
5. Names and concerns of parties involved;
6. Current mitigation of the problem;
7. Possible cause of the problem; and
8. Whether the project is likely to aggravate the problem or create a new one.
Upon review of this analysis, the Administrator may require mitigation measures deemed
adequate for the problems, or a quantitative analysis, depending upon the presence of existing or
predicted flooding, erosion, or water quality problems, and on the proposed design of the onsite
drainage facilities. The analysis should repeat Tasks 3 and 4 above, using quantitative field data
including profiles and cross-sections.
The quantitative analysis should provide infonnation on the severity and frequency of an existing
problem or the likelihood of creating a new problem. It should evaluate proposed mitigation
intended to avoid aggravation of the existing problem and to avoid creation of a new problem.
J. In Volume I, Section 2.7 of the Manual, "Adjustments", is amended to read as follows:
Adjustments to the Minimum Requirements may be granted prior to permit approval and
construction. The Administrator may grant an adjustment provided that a written finding of
fact is prepared, that addresses the following:
1. The adjustment provides substantially equivalent environmental protection.
2. The objectives of safety, function, environmental protection and facility maintenance,
based upon sound engineering, are met.
K. In Volume III, Section 3.1.2 of the Manual, "Downspout Dispersion Systems", is not
adopted.
L. In V o\ume III, Section 3.1.3 of the Manual, "Perforated Stub-out Connections", is not
adopted.
M. In Volume III, Section 3.2 of the Manual. Figure 3.12, "Pond Signage", is amended to
include the following language: "Developers shall provide the required signage for
constructed ponds as a part of the project."
N. In Volume V: Section 4.3 "Setbacks, slopes and embankments", is amended to include the
following language:
All stornlwater facilities and infiltration systems constructed within 200 feet of a geohazard
area shall have the concurrence of a Geotechnical Engineer.
O. In Volume V, Section 5.3.1 of the Manual, "BMP T 5.10 Downspout Dispersion" is not
adopted.
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Ordinance #2005-10
Stormwater Ordinance
November 22, 2005
P. In Volume V, Section 5.3.2 of the Manual, "BMP T 5.21 Better Site Design: Build Narrower
Streets" is amended to include the following language:
Streets and roadways must, however, comply with City of Bainbridge Island Design and
Construction Standards and Specifications unless an exception is granted in writing by the
Administrator.
Q. In Volume V, Section 5.3.3 of the Manual, "BMP T 5.30 Full Dispersion" is not adopted.
R. In Volume V of the Manual, Chapter 12, "Emerging Technologies", is not adopted.
Section 6.
follows:
Section 15.20.070 of the Bainbridge Island Municipal Code is amended as
15.20.070 Administration.
A. Administrator
The Public Works Director or a designee shall administer this ordinance and shall be referred
to as the Administrator. The Administrator shall have the authority to develop and
implement administrative procedures to administer and enforce this ordinance.
B. Review and Approval.
The Administrator may approve, conditionally approve or deny an application for activities
regulated by this ordinance.
C. Enforcement Authority. The administrator shall enforce this ordinance.
D. Inspection. All activities regulated by this ordinance, except those exempt in Volume I,
Section 2.8 of the Manual, "Exceptions and Variances shall be inspected by the
Administrator. The Administrator shall inspect projects at various stages of the work
requiring approval 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, permanent storm water control facilities,
landscaping, retaining walls and completion of project. When required by the Administrator,
a special inspection and/or testing shall be performed
Section 7.
follows:
Section 15.20.080 of the Bainbridge Island Municipal Code is amended as
15.20.080 Enforcement.
Enforcement action shall be in accordance with Bainbridge Island Municipal Code Chapter 1.26,
whenever a person has violated any provision of this Chapter. The choice of enforcement action
and the severity of any penalty shall be based on the nature of the violation, the damage or risk to
the public or to public resources, and/or the degree of bad faith ofthe person subject to the
enforcement action,
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Ordinance #2005-10
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Section 8.
follows:
Section 15.20.090 of the Bainbridge Island Municipal Code is amended as
15.20.090 Exceptions
A. Exceptions may be granted prior to pefilit approval and construction. The Administrator
may grant an exception following public notice in accordance with the administrative code
for the State Environmental Policy Act (SEP A) provided that a written finding of fact is
prepared, that addresses the following:
1. The exception provides substantially equivalent environmental protection and is in the
overriding public interest; and that the objectives of safety, function, environmental
protection and facility maintenance, based upon sound engineering, are fully met; AND
2. That there are special physical circumstances or conditions affecting the property such
that the strict application of these provisions would deprive the applicant of all reasonable
use of the parcel ofland in question, and every effort to find creative ways to meet the
intent of the minimum requirements has been made; AND
3. That the granting of the exception will not be detrimental to the public health and
welfare, nor injurious to other properties in the vicinity and/or downstream, and to the
quality of water of the state; AND
4. The exception is the least possible exception that could be granted to comply with the
intent of the Minimum Requirements.
5. Utilization of Low Impact Development (LID) practices will be encouraged to address
exceptions of A through D above. Each proposed LID practice will be evaluated on a
case by case: basis by the Administrator.
B. Prior Approval. Any exception shall be approved prior to permit approval and construction.
C. Duration of Exception. Exceptions granted shall be valid for two years, unless granted for a
shorter period.
D. Right of Appeal. All actions of the City Council shall be final and conclusive, unless within
twenty (20) days of the date of the City Council action, the original applicant or an adverse
party gives written notice of appeal to the City Council for review of the action.
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Ordinance #2005-10
Storrnwater Ordinance
November 22, 2005
Section 9. This ordinance shall be effective five days after passage, approval and publication
as required by law.
PASSED by the City Council this 22nd day of November, 2005.
APPROVED by the Mayor this 23rd day of November, 2005.
~~/~vU~
Darlene Kordonowy, Mayor I ~
ATTrsT/AUTHEN.!ICATE:
,~~^-" V~ /~-f~L-
Susan Kasper, City Clerk
APPROVED AS TO FORM:
Rod Kaseguma, City Attorney
FILED WITH THE CITY CLERK:
PASSED BY THE CITY COUNCIL:
PUBLISHED:
EFFECTIVE DATE:
ORDINANCE NUMBER: 2005-10
November 2, 2005
November 22, 2005
November 30, 2005
December 5, 2005
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