Ordinance 1924ORDINANCE NO. 1924
AN ORDINANCE OF THE CITY OF EDMONDS, WASHINGTON,
ESTABLISHING A NEW CHAPTER 12.17 OF THE EDMONDS
CITY CODE AND REQUIRING A DRAINAGE PLAN TO BE
SUBMITTED IN CONJUNCTION WITH CERTAIN PERMITS,
SPECIFYING THE CONTENTS THEREOF, REQUIRING SURETY
AND CASH BONDS, AUTHORIZING CITY ASSUMPTION OF
RETENTION AND DETENTION FACILITIES.
WHEREAS, an expanding city population and increased
development of land will lead to drainage and run-off
problems unless adequate provision is made for the same, and
WHEREAS, these drainage and run-off problems contribute
to increased siltation of the ponds, -creeks, streams, thereby
degrading water quality, and
WHEREAS, inadequate drainage planning leads to erosion
and concomitant property damage, and
WHEREAS, excess water run-off coming upon streets and
highways will pose a safety hazard to both lives and property,
and
WHEREAS, the City Council finds that these problems
could be resolved if developers gave careful consideration to
the drainage of their property, now, therefore,
THE CITY COUNCIL OF THE CITY OF EDMONDS, WASHINGTON, DO
ORDAIN AS FOLLOWS:
Section 1. There is hereby created a new Chapter, 12.17,
of the Edmonds City Code entitled, "Surface Water Drainage
Plans."
Section 2. 12.17.010. Purposes. The City Council
finds that this Chapter is necessary in order to minimize
water quality degradation by preventing the sedimentation of
the creeks, streams, ponds, lakes and other water bodies; to
protect property owners adjacent to developing land from
increased run-off rates which could cause erosion of abutting
property; to promote sound development policies which re-
spect and preserve the City's water courses; to insure the
safety of City roads and rights -of -way; and to decrease
surface water damage to public and private property.
Section 3. 12.17.020. Definitions.
(1) "Comprehensive drainage plan" refers to a detailed
analysis for each drainage basin which compares
the capabilities and needs for run-off accommodation
due to various combinations of development, land
use, structural and nonstructural management
alternatives. The plan recommends the form,
location and extent of quantity and quality con-
trol measures which will meet legal requirements,
water quality standards, and community standards,
as well as identifying institutional and funding
requirements for plan implementation.
(2) "Computations" shall mean calculations, includ-
ing coefficients and other pertinent data,
made to determine the drainage plan with rates
of flow of water given in cubic feet per sec-
ond (cfs) .
(3) "Design Storm" shall mean that rainfall event
selected by the DPW for the purposes of design,
specifying both the return period in years and the
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duration in hours.
(4) "Developmental coverage" shall mean all developed
surface areas within the subject property including,
but not limited to, rooftops, driveways, carports,
accessory buildings, parking areas, and other
impervious surfaces.
(5) "Director of Public Works (DPW)" is the DPW or his
designee.
(6) "Drainage area" shall mean the watershed (acreage)
contributing surface water runoff to and including
the subject property.
(7) "Drainage guideline manual" shall mean the manual of
technical and administrative procedures established
by the Public Works Department which specifies
methods to be used, the level of detail of analysis
required, and other details for implementation of
the provisions of this Chapter.
(8) "Drainage plan" shall mean a plan for receiving,
handling, and transporting surface water within
the subject property.
(9) "Drainage treatment/abatement facilities" shall
mean any facilities installed or constructed in
conjunction with a drainage plan for the purpose
of treatment or abatement of urban runoff, excluding
retention or detention facilities.
(10) "Open Channel" shall mean a ditch, swale or
stream section which will provide capacity for
the maximum design storm flow. The top of the
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(12)
(13)
(14)
bank of the open channel will be one foot above
the maximum flow line for the designed storm.
"Peak discharge" shall mean the maximum sur-
face water run-off rate (cfs) determined for the
design storm frequency prior to the development.
"Receiving bodies of water" shall mean creeks,
streams, lakes and other bodies of water into
which surface waters are directed, either natu-
rally, or in man-made ditches or open systems.
"Retention/detention facilities" shall mean fa-
cilities designed either to hold run-off for a
short period of time and then releasing it to the
natural watercourse or to hold water for a consid-
erable length of time and then consuming it by
evaporation, plants, or infiltration into the
ground.
"Subject property" shall mean the tract of land
which is the subject of the permit and/or approval
action.
Section 4. 12.17.030. Submission of a Drainage Plan.
(1)
All persons applying for any of the following
permits and/or approvals shall submit for approval
a drainage plan with their application and/or
request:
(a) Grading Permit
(b) Substantial development permit required
under RCW 90.58 (Shoreline Management
Act)
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(c) Subdivision approval
(d) Short subdivision approval
(e) Rezones
(f) Conditional use permits effecting a
drainage change
(g) Building permits where the permit re-
lates to 5,000 or more square feet of
developmental coverage within the
property
(h) Planned Residential Development.
Commencement of construction work under any of the
above permits or applications shall not begin until final
approval of the drainage plan is obtained in accordance with
Section 12.17.070 of the Edmonds City Code.
(2) The same plan submitted during one permit/approval
process may be subsequently submitted with further
required applications. The plan shall be supple-
mented with such additional information that is
requested by the DPW or required by the provisions
of the Drainage Guideline Manual.
(3) The plan requirement established in this section
will not apply when the DPW determines that the
proposed permit and/or activity:
(a) Will not seriously and adversely impact the
water quality conditions of any affected
receiving bodies of water, and
(b) Will not alter the drainage patterns, in-
crease the peak discharge or surface or
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subsurface or cause any other adverse effects
in the drainage area.
Section 5. 12.17.040. Contents of a Drainage Plan.
All persons applying for any of the permits and/or approvals
contained in Section 12.17.030 of the Edmonds City Code
shall provide a drainage plan for surface and pertinent
subsurface water flows entering, flowing within, and leaving
the subject property. The detailed form and.contents of the
drainage plan shall be described in procedures established
by the DPW in the Drainage Guideline Manual. The procedures
will set forth the manner of presenting the following re-
quired information:
(1) Background computations for sizing drainage fa-
cilities:
(a)
Depiction of the drainage area on a topo-
graphical map, with acreage indicated.
(b)
Indication of the peak discharge and amount
of surface water currently entering and leav-
ing the subject property.
(c)
Indication of the peak discharge and amount
of run-off which will be generated within the
subject property if development is allowed to
proceed.
(d)
Determination of the peak discharge and
amount of water that will be generated by ten
(10) year storm frequencies at various points
on the subject property.
(2) Proposed
improvements for handling the computed
run-off.
(3) At the time of approval of the drainage plan for
the subject property, a schedule for inspection of
construction and facilities will be established by
the Director of Public Works.
Section 6. 12.17.050. Mandatory Requirements for
Drainage Improvements.
(1) (a) Surface water entering the subject property
shall be received at the naturally occuring
location and surface water exiting the sub-
ject property shall be discharged at the
natural location with adequate energy dissi-
pators within the subject property to mini-
mize downstream damage and with no diversion
stream at any of these points; and
(b) The peak discharge from the subject property
may not be increased due to the proposed
development; and
(c) Retention/detention facilities must be pro-
vided in order to handle all surface water in
excess of the peak discharge that was present
prior to the development.
(d) Where open channel construction is used to
handle drainage within the tract, a minimum
of fifteen (15) feet shall be provided be-
tween the structures and the top of the bank
of the defined channel.
(i) In open channel work the water surface
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elevation shall be indicated on the plan
and profile drawings. The configuration
of the finished grades constituting the
banks of the open channel will also be
shown on the drawings.
(ii) Proposed cross section of the channel
shall be shown with stable side slopes
as approved by the DPW.
(iii) The maximum water surface elevation of
the design flow shall be indicated on
the cross section.
(e) When a closed system is used to handle drain-
age within the tract, all structures shall be
a minimum of ten feet from the closed system.
(2) Deviations from any or all of the foregoing require-
ments may be permitted only after a determination
by the DPW using the Comprehensive Drainage Plan
and employing the following criteria:
(a) Capacity of downstream facilities;
(b) Acceptability of receiving bodies of water;
(c) Possibility of adverse effects of retention;
(d) Utility of regional retention facilities; and
capability of maintenance of the system.
Section 7. 12.17.060. Development in Critical Flood
Drainage and/or Erosion Areas. Development which would in-
crease the volume of discharge from the subject property
shall not be permitted in areas where existing flooding,
drainage and/or erosion conditions present an imminent
likelihood of harm to the welfare and safety of the sur-
rounding community, until such time as the community hazard
is alleviated.
Section 8. 12.17.070. Review and Approval of the
Plan --Appeal. All storm drainage plans prepared in connec-
tion with any of the permits and/or approvals listed in Sec-
tion 12.17.030 of the Edmonds City Code shall be submitted
for review by and approval of the DPW.
Appeals from the approval or denial by the DPW shall
be made in writing to the City Council within ten (10) days
from the date of the DPW's decision. The City Council in
deciding the appeal, shall follow the criteria as set forth
in this Chapter, the Comprehensive Drainage Plan and the
Drainage Guideline Manual. Provided, however, that stand-
ards relating to methods of construction or materials adopted
by the City or established by the DPW shall not be varied,
modified or waived by the City Council.
Any appeal from the decision of the City Council shall
be made within ten (10) days of the City Council's decision
to the Snohomish County Superior Court.
Section 9. 12.17.080. Establishment of Regional
Facilities. If modifications of the Drainage Plan for the
subject property would better implement the provisions of
the Comprehensive Drainage Plan, the Director of Public
Works may recommend to the City Council that the City should
assume responsibility for the further design, construction,
and maintenance of drainage facilities on the subject property.
In the event the City assumes responsibility for design,
construction, and maintenance of the facilities, the de-
veloper shall be required to pay the portion of the design
and construction costs of the facilities which would be
required for and are attributable to, the subject property.
Section 10. 12.17.090. Bonds, Release and Indemnifi-
cation Required. The DPW is authorized to require all
persons constructing retention/detention facilities to post
performance, maintenance and cash bonds.
(1) Performance Bond. Prior to commencing construc-
tion, the person constructing the facility shall
post a performance bond or other suitable security
guaranteeing construction will occur in an amount
sufficient to cover the cost of conforming said
construction with the approved drainage plans and
in a form approved by the City. The amount of the
bond shall be increased at one-year intervals in
a proportion equal to the prevailing rate of
inflation in construction costs. After determina-
tion by the DPW that all facilities are constructed
in compliance with the approved plans and upon
providing maintenance bond as hereinafter provided,
the performance bond shall be released.
(2) Maintenance Bond. After satisfactory completion
of the facilities, the person constructing the
facility shall maintain the facility for a period
of two years. A maintenance bond, or other suitable
security, shall be maintained throughout the two-
year period. The bond amount shall be set by the
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DPW in an amount sufficient to cover the costs of
correcting all deficiencies in construction,
design, workmanship or maintaining and operating
the facility.
(3) The owner of the subject property shall execute a
release and a covenant running with the land
binding on himself, his heirs, assigns and succes-
sors in interest, as well as all future owners of
the property to indemnify, defend and hold the
City harmless from any and all claims for damages
of whatever nature, or injunctive relief occasioned
by the construction, operation or maintenance of
the drainage facilities. This covenant shall be
recorded at owner's expense.
Section 11. 12.17.100. City Assumption of Maintenance.
At its option, the City shall assume the maintenance of
retention/detention facilities on private property if the
retention/detention facilities are judged by the DPW to be
for public benefit. Any decision by the DPW to forego
assumption of the maintenance of retention/detention fa-
cilities shall be made prior to approval of the drainage
plan. If the City decides not to assume the maintenance of
the retention/detention facilities, the developer shall make
arrangements for assumption of maintenance in a manner
approved by the DPW. Such arrangements shall be completed
and approved prior to the end of the two-year period of
developer responsibility.
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Should the City assume maintenance, the following con-
ditions shall be met:
(1) All of the requirements of Section 12.17.090 of
the Edmonds City Code have been fully complied with;
(2) The facilities have been inspected and approved by
the DPW after two (2) years of operation;
(3) All necessary easements entitling the City to
properly maintain the facility have been conveyed
to the City and recorded with the Snohomish County
Auditor at the owner's expense.
Section 12. 12.17.110. Applicability to Governmental
Entities. All municipal corporations and governmental
entities shall be required to submit a drainage plan and
comply with the terms of this Chapter when developing and/or
improving land including, but not limited to, road building
and widening, within the areas of the City.
Section 13.
12.17.120. Effective Date. The require-
ments of this chapter shall apply to all plats receiving
final and preliminary approval subsequent to the effective
date of this Chapter. In the case of all additional ac-
tions enumerated in Section 12.17.030 of the Edmonds City
Code, the terms of this chapter shall apply where final
action by the City has not been taken prior to the effective
date of this Ordinance.
Section 14. 12.17.130. Establishment of Drainage
Guideline Manual. The DPW is hereby authorized and directed
to conduct studies, assemble data, establish rules, regu-
lations and procedures, and take all other steps necessary
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to prepare the Drainage Guideline Manual.
Section 15. 12.17.300. Severability. If any sec-
tion, subsection, clause, phrase, or word of this Ordinance
or any provision adopted by reference herein is for any
reason held to be invalid or unconstitutional by a court of
competent jurisdiction, such invalidity or unconstitutionality
shall not affect the validity or constitutionality of the
remaining portions of this Ordinance.
APPROVED:
,'H. H. HARRISON
MAYOR
ATTEST:
CITY CLERK, IRENg VARNEY MORAN
FILED WITH THE CITY CLERK: June 24, 1977
PASSED BY THE CITY COUNCIL: June 28, 1977
PUBLISHED: July 6, 1977
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