HomeMy WebLinkAbout6761 ORDINANCE NO. 6761
AN ORDINANCE OF THE CITY COUNCIL OF THE CITY OF
AUBURN, WASHINGTON, RELATING TO FLOOD HAZARD
AREAS AND AMENDING CHAPTER 15.68 OF THE
AUBURN CITY CODE
WHEREAS, the City is required as a condition of continued eligibility in the National
Flood Insurance Program to adopt floodplain management regulations that meet the
requirements of the federal floodplain management criteria for flood-prone areas; and
WHEREAS, state law requires cities to periodically review and update their Critical
Areas ordinances, one element of which is floodplain management regulations; and
WHEREAS, federal and state criteria for floodplain management have changed
since the City last revised its floodplain management regulations, in 2010; and
WHEREAS, to assist local governments update their codes, FEMA (Federal
Emergency Management Agency) provides cities with a floodplain management model
ordinance; and
WHEREAS, the City must revise its regulations to reference the latest Flood
Insurance Study, accompanying Flood Insurance Rate Maps (FIRMs), and supporting
information being adopted by FEMA and
WHEREAS, updating the floodplain management regulations enhances flood
safety and reduces flooding risks through premptive planning and by improving local
standards to reflect current science.
NOW, THEREFORE, THE CITY COUNCIL OF THE CITY OF AUBURN,
WASHINGTON, DO ORDAIN as follows:
Ordinance No. 6761 1
May 26, 2020
Page 1 of 2
Section 1. Amendment to City Code. Chapter 15.68 of the Auburn City Code
is repealed and reenacted to read as shown in Exhibit A.
Section 2. Implementation. The Mayor is authorized to implement those
administrative procedures necessary to carry out the directives of this legislation.
Section 3. Severability. The provisions of this ordinance are declared to be
separate and severable. The invalidity of any clause, sentence, paragraph, subdivision,
section, or portion of this ordinance, or the invalidity of the application of it to any person
or circumstance, will not affect the validity of the remainder of this ordinance, or the validity
of its application to other persons or circumstances.
Section 4. Effective date. This Ordinance shall be effective and in force five
days from and after the passage, approval, and publication of this Ordinance as provided
by law but shall be implemented beginning on August 18, 2020.
INTRODUCED: JUN 0 1 2020
PASSED: JUN 0 1 2020
APPROVED: JUN 0 1 2020
ANCY US,
1MAYR
ATTEST: 7/ED AS TO F ML
Shawn Campbe II MMC, City Clerk Kendra Comeau, City Attorney
Published: \,A.t I /V 7V ►4 ` -1G.At K bbb-ej
Ordinance No. 6761 1
May 26, 2020
Page 2 of 2
Ord. 6761 Exhibit A
ACC Chapter 15.68
Strikethrough Underline
1
Chapter 15.68
FLOOD HAZARD AREASFLOODPLAIN DEVELOPMENT MANAGEMENT
Sections:
Article 1. Purpose
15.68.010 Rosorvod.
15.68.020 Reserved.
15.68.030 Statement of purpose.
... ".
.
15.68.060 Definitions.
Article Ill. General Provisions
15.68.070 Land to which this chapter applies.
15.68.080 Rosorvod.
II -
15.68.110 Interpretation.
15.68.120 Warning and disclaimer of liability.
15.68.125 Appeals.
.. .- /. -:•••••
..
.-
' .._'
e. .. . . i.
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Aftis' ose
Section 1.General
15.68.010 Statutory Authorization.
15.68.020 Purpose.
15.68.030 Lands to which this Ordinance Applies.
15.68.040 Approach.
15.68.050 Penalties for Non-Compliance.
15.68.060 Interpretation.
15.68.070 Abrogation and Greater Restrictions.
15.68.080 Warning and Disclaimer of Liability.
15.68.090 Severability.
Section 2. Definitions
15.68.100 Definitions.
Section 3. Regulatory Data
15.68.110 Area to be Regulated.
15.68.120 Special Flood Hazard Area.
15.68.130 Flood Hazard Data.
15.68.140 Protected Area.
15.68.150 New Regulatory Data.
Section 4.Administration
15.68.160 Establishment of Floodplain Development Permit.
15.68.170 Floodplain Development Permit Application.
15.68.180 Floodplain Development Permit Expiration.
15.68.190 Designation of the Floodplain Administrator.
15.68.200 Duties of the Floodplain Administrator.
15.68.210 Notification to Other Entities.
15.68.220 Records.
15.68.230 Certificate of Occupancy.
15.68.240 Appeals.
15.68.250 Variance Criteria.
Section 5.General Development Standards
15.68.260 Subdivisions.
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15.68.270 Site Design.
15.68.280 Hazardous Materials.
15.68.290 Critical Facilities.
Section 6. Standards for Protection of Structures
15.68.300 Applicability.
15.68.310 Flood Protection Standards.
15.68.320 Nonresidential Construction.
15.68.330 Manufactured Homes.
15.68.340 Recreation Vehicles.
15.68.350 Appurtenant Structures.
15.68.360 Utilities.
Section 7.Standards for Habitat Protection
15.68.370 Non-Development Activities.
15.68.380 Activities Allowed with a Floodplain Development Permit.
15.68.390 Other Activities.
15.68.400 Native Vegetation.
15.68.410 Floodway Standards.
15.68.420 Standards for Shallow Flooding Areas(AO Zones)
15.68.430 Compensatory Storage.
15.68.440 Habitat Impact Assessment.
15.68.450 Habitat Mitigation Plan.
15.68.460 Alteration of Watercourses and SFHA Boundaries.
Section 1. General
15.68.010 Rote^ped Statutory Authorization.
A. The Legislature of the State of Washington has delegated the responsibility to local governmental units
to adopt regulations designed to promote the public health, safety and general welfare of its citizenry.
Therefore, the City does ordain as follows:
B. Findings of Fact:
Areas of Auburn are subject to periodic inundation and channel migration which may result in loss of life and
property, health and safety hazards, disruption of commerce and governmental services, extraordinary public
expenditures for protection and relief from flooding and channel migration, and impairment of the tax base,all
of which adversely affect the public health, safety and general welfare.
When floodplains and watersheds are developed without taking appropriate care and precautions, flood
heights, frequencies, and velocities increase, which may cause a greater threat to humans, damage to
property, destruction of natural floodplain functions, and adverse impacts to water quality and habitat.
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Rivers, streams, lakes,estuarine and marine areas and their floodplains are major elements of healthy aquatic
and riparian areas and conveyance of flood waters. If watersheds, rivers, streams, lakes, estuaries,floodplains
and other systems are not viewed holistically as biological and geomorphologic units, it may lead to serious
degradation of habitat and increased flood hazards to people and human development.
Over the years, natural processes have evolved that manage flood waters and channel flows in the most
effective and efficient manner. Disruption of these processes through alterations to land cover, stream
channels,wetlands and other water bodies which may lead to increased flood hazards, loss of life and
property,threats to public health, and loss of habitat.
15.68.020 ed Purpose.
15.68.030 Statement of purpose.
It is the purpose of this shapterordinance to promote the public health, safety, and general welfare and to
minimize public and private losses due to flood conditions in specific areas by provisions designed to manage
development in order to:
A. . To protect. Protect human life, health;and te-pretest-property from the dangers of flooding;
B. B. To minimizeMinimize the need for publicly funded and hazardous rescue efforts to save those who
are isolated by floodwaters
B C. Minimize expenditure of public money andfor costly flood damage repair and flood control projects;
D. E. To minimizoMinimize disruption of commerce, governmental services,and government
infrastructure.,
GE. Minimize damage to public facilities and utilities such as water and gas mains, electric,telephone and
sewer lines, streets and bridges located in ;the floodplain.;
F. Minimize cost impacts to public facilities and utilities such as water and pas mains, electric,telephone
and sewer lines, streets and bridges located in the special flood hazard area.;
Maintain a stable tax base by providing for the sound use and-development-of and
development of flood hazard areas so as to minimize fu4 e-ieedlablight areas
caused by flooding;
H. To ensure thatEncourage those who occupy flood hazard t—areas
H. 1. To qualify be educated about the oifyrisks and challenges associated with these areas.
l=I.
Qualify the City of Auburn for participation in the National Flood Insurance Program, thereby giving
citizens and businesses the opportunity to purchase flood insurance;
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J. To maintainMaintain the quality of water in rivers, streams, and lakes, and their floodplains so as to
protect public water supplies, areas of the astPublic Trust, and wildlife habitat protected by the
Endangered Species Act;
-K. K. To retainRetain the natural channel, shoreline, and floodplain creation processes and other natural
floodplain functions that protect, create, and maintain habitat for threatened and endangered species; and
i-L. L. To preventPrevent or minimize loss of hydraulic, geomorphic, and ecological functions of
floodplains and stream channels.
15.68.030 Lands to which this Ordinance Applies.
This ordinance shall apply to the Special Flood Hazard Area (SFHA) and associated protected areas within the
jurisdiction of the City of Auburn as defined in Section 3 of this Ordinance.
15.68.040 - -- - - - '= " Approach.
In order to assempiish-itsachieve the listed purposes, this -•-: = •- ---- .." •..• -•.- - - e•
fecordinance:
A. Defines and clarifies the terms and phrases used in this ordinance in Section 2.
- - , e .•: - • • - •- •-• . - • . . . . '0--
Identifies in other areas;
._ _ _ . _ . :Section 3 the pretested
areaSpecial Flood Hazard Area,the Protected Area and the supporting technical data needed to delineate
those areas;_
C. G. EstablichingEstablishes a permit requirement in Section 4 so that all iaaaaaproposed development
that may affect flood hazards,water quality,and habitat is reviewed ;prior to
construction.
D. 4=1--SettingSets minimum protection standards in Section 5 for all development to ensure that the
development will not increase the potential for flood damage or adversely affect natural floodplain functions;,
E. J. SettingSets minimum protection standards to protect new and substantially improved structures
from flood damaged in Section 6.
F. J--SpesifyiagSpecifies additional habitat protection criteria-in Section 7. Some small projects do not
need a floodplain development permit(see ACC=.:_. -•=
15.68.130(D)).15.68.380). For all other development projects,the applicant must assess their impact on those
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factors that contribute to increased flood hazard and degradation of habitat. If the assessment concludes that
thorothe project will because an adverse effect outside the Protected Area,the permit will be denied, unless the
project -- .'e - - •• -- - •- -- - - • -.impacts are mitigated (avoided, minimized, restored or
compensated for).
15.68.050 Penalties for Noncompliance.
No development shall be undertaken or placed in the areas regulated by this ordinance without full compliance
with the terms of this ordinance and other applicable regulations of the City. Violation of the provisions of this
chapter by failure to comply with any of its requirements(including violations of conditions and safeguards
established in connection with conditions)shall be enforced pursuant to the provisions of Chapter 1.25 ACC.
15.68.060 Interpretation-elf-language.
In the interpretation and application of this ordinance, all provisions shall be:
A. Considered as minimum requirements;
B. Liberally construed in favor of the City; and,
RC. Deemed neither to limit nor repeal any other powers granted under state statutes;
15.68.070 Abrogation and Regulation Conflicts
Where this ordinance and another code, or ordinance,conflict or overlap,whichever imposes the more
stringent restrictions shall prevail.
15.68.080 Warning and Disclaimer of Liability.
The degree of property and habitat protection required by this ordinance is considered reasonable for
regulatory purposes and is based on scientific and engineering considerations. Larger floods and movement of
channels outside of mapped channel migration areas may occur on rare occasions. Flood heights may be
increased by ceabmadeunnatural or natural causes. This ordinance does not imply that land outside the
regulated areas or development permitted within such areas will be free from flood or erosion damage. This
ordinance shall not create liability on the part of the City,any officer or employee thereof, for any damage to
property or habitat that results from reliance on this ordinance or any administrative decision lawfully made
thereunder.
15.68.090 Severability
The provisions and sections of this ordinance shall be deemed separable and the invalidity of any portion of
this ordinance shall not affect the validity of the remainder.
Section 2. Definitions
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15.68.100 Definitions.
Unless specifically defined below,terms or phrases used in this s iapteFordinance shall be
interpreted so as to give them the meaning they have in common usage and to give this oIaptecordinance its
most reasonable application.
A. 15.68.060 Definitions.
B. As used in this chapter:
C. . . "Adversely affect/adverse effect"means effects that are a direct or indirect result of the proposed
action or its interrelated or interdependent actions and the effect is not discountable, insignificant,or beneficial;
where:
D. 1. a. _Discountable effects are extremely unlikely to occur +ad
E. b. -Insignificant effects relate to the size of the impact and should never reach the scale where a take
occurs. Based on best judgment, a person would not: 1)be able to meaningfully measure, detect, or evaluate
insignificant effects, or 2 .expect discountable effects to occur.
F-A. 2—Beneficial effects are contemporaneous positive effects without any adverse effects. In the event
that the overall effect of the proposed action is beneficial, but is also likely to cause some adverse effects,then
the proposed action is considered to result in an adverse effect.
B. —"Alteration of watercourse" means any action that will change the location of the channel occupied
by water within the banks of any portion of a riverine waterbody.
C. "Appurtenant Structure" means a structure which is on the same parcel as the principle structure to be
insured and the use of which is incidental to the use of the principal structure.
D. "Area of shallow flooding" means a designated zone AO,AH, AR/AO or AR/AH (or VO)on a
community's Flood Insurance Rate Map(FIRM)with a one percent or greater annual chance of flooding to an
average depth of one to three feet where a clearly defined channel does not exist,where the path of flooding is
unpredictable, and where velocity flow may be evident. Such flooding is characterized by ponding or sheet flow.
Also referred to as the sheet flow area.
E. "Area of special flood hazard" means the land in the floodplain within a community subiect to a 1
percent or greater chance of flooding in any given year. It is shown on the Flood Insurance Rate Map (FIRM)
as zone A, AO,AH,A1-30,AE,A99,AR(V, VO,V1-30,VE). "Special flood hazard area" is synonymous in
meaning with the phrase"area of special flood hazard".
F. "ASCE 24" means the most recently published version of ASCE 24, Flood Resistant Design and
Construction, published by the American Society of Civil Engineers.
G. "Base flood" means the flood having a one percent chance of being equaled or exceeded in any given
year. Also(also referred to as the"100-year flood •- e lee:.
H. C. "Base flood elevation" means the elevation - •- .--' '::° -e:
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H. - e- 'eee - - - e .. — — '- e -- - •• - 'eee
_ _ _ - •- 'e e e .•-_ -•-- - -e to which floodwater is anticipated to rise during the base flood for the city.
J. 2. The base flood elevation for each SFHA delineated as a Zone AH or Zone AO shall be that
• e •- - °- - -- - -- -
strusture.
3. Where base flood elevation data arc not provided on the flood incurance ctudy for the city, base
"Basement"means any area of the structure having its floor subgrade (below ground level)on all
sides.
J. E--.—"Building Code" means the currently effective versions of the International Building Code and the
International Residential Code adopted by the Washington State Legislature and any further amendments
adopted by the City of Auburn.
ASK. "Channel migration-area-Migration Zone" (CMZ) means the area within the lateral extent of likely
stream channel movement due to stream bank destabilization and erosion, rapid stream incision, aggradation,
avulsions, and shifts in location of stream channels plus 50 feet.
1. 1-The channel migration area shall be the total area occupied by the river channel,the
severe channel migration hazard area, and the moderate channel migration hazard area as delineated
in the Green River Channel Migration Study published by King County dated December 1993 plus 50
feet.
2. —The channel migration area shall be the total area occupied by the river channel, the
severe channel migration hazard area, and the moderate channel migration hazard area as delineated
in the Channel Migration Zone Delineation for the Middle Green River, RM 31.10 to 33.25 dated
December 28, 2018 plus 50-feet which supersedes the study referenced above.
3. A site specific channel migration delineation may also be performed per the Washington State
Department of Ecology's current requirements with recommended setbacks (A Framework for
Delineating Channel Migration Zones)prepared by a qualified engineer. The delineation shall be
prepared by a qualified consultant as that term is defined in these regulations. The city may retain a
qualified consultant paid for by the applicant to review and confirm the applicant's reports, studies and
plans if the following circumstances exist:
a. The city has technical information that is unavailable to the applicant; or
b. The applicant has provided inaccurate or incomplete information on previous
proposals or proposals currently under consideration.
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ISL. "Critical facility" means a facility necessary to protect the public health, safety and welfare during a
flood. Critical facilities include, but are not limited to, schools, nursing homes, hospitals, police, fire and
emergency operations installations,water and wastewater treatment plants, electric power stations, and
installations which produce, use, or store hazardous materials or hazardous waste (other than consumer
products containing hazardous substances or hazardous waste intended for household use).
O M. G—"Development" means any manmadchuman-made change to improved or unimproved real estate
including but not limited to buildings or other structures, mining, dredging,filling,
grading, paving, excavation or drilling operations or storage of equipment or materials located within the area of
special flood hazard, . - :, -•• - . . . . _ - •- - ' - - •-
property, or alteration of natural site characteristics.
N. 44—"Dry floodproofing"means any combination of structural and nonstructural measures that prevent
flood waters from entering a structure.
4O. 4,—"Elevation sertifisateCertificate" means an administrative tool of the National Flood Insurance
Program (NFIP)that can be used to provide elevation information,to determine the proper insurance premium
rate, and to support a request for a Letter of Map Amendment(LOMA) or Letter of Map Revision based on fill
(LOMR-F). •- - .. ..
available 10 year, 50 year and 100 year water surface profiles.
P. I--"Essential Facility" has the same meaning as"Essential Facility"defined in ASCE 24. Table 1-1 in
ASCE 24-14 further identifies building occupancies that are essential facilities.
&Q. "FEMA" means the Federal Emergency Management Agency, the agency responsible for
administering the National Flood Insurance Program.
0841),
R. M— Flood"or"flooding"means a general and temporary condition of partial or complete inundation of
normally dry land areas from:
1. —The overflow of inland or tidal waters; and/or
2. . _The unusual and rapid accumulation of runoff of surface waters from any source.
3. N. 3. Mudslides(i.e., mudflows)which are proximately caused by flooding as defined in
paragraph 4a3(2)of this definition and are akin to a river of liquid and flowing mud on the surfaces of
normally dry land areas, as when earth is carried by a current of water and deposited along the path of
the current.
4. The collapse or subsidence of land along the shore of a lake or other body of water as a result
of erosion or undermining caused by waves or currents of water exceeding anticipated cyclical levels
or suddenly caused by an unusually high water level in a natural body of water, accompanied by a
severe storm, or by an unanticipated force of nature, such as flash flood or an abnormal tidal surge, or
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by some similarly unusual and unforeseeable event which results in flooding as defined in paragraph
(1)44 of this definition.
S. "Flood elevation study" means an examination, evaluation and determination of flood hazards and, if
appropriate, corresponding water surface elevations,or an examination, evaluation and determination of
mudslide(i.e., mudflow)and/or flood-related erosion hazards. Also known as a Flood Insurance Study (FIS).
V,T. "Flood insurance rate map (FIRM)" means the official map on which the Federal Insurance
Administratiogr has delineated both the Special Flood Hazard Areas and the risk
premium zones applicable to the community.
W,U. Q--"Flood insurance study(FIS)" See"Flood Elevation Study"---• •
V. p--"Floodplain or flood prone area" means any land area susceptible to being inundated by water
from any source. See"Flood or flooding."
W. "Floodplain administrator" means the community official designated by title to administer and enforce
the floodplain management regulations.
X. "Flood proofing" means any combination of structural and nonstructural additions, changes, or
adjustments to structures which reduce or eliminate risk of flood damage to real estate or improved real
property,water and sanitary facilities, structures,and their contents. Flood proofed structures are those that
have the structural integrity and design to be impervious to floodwater below the Base Flood Elevation.
XY. "Flood protection elevation (FPE)" means the elevation above the datum of the effective FIRM to which
new and substantially improved structures must be protected from flood damage.
Y-Z. Q--"Floodway" means the channel of a river-stream or other watercourse and the adjacent land areas
that must be reserved in order to discharge the base flood without cumulatively increasing the water surface
dway
elevation more than a designated height.Also referred to the`Regulatory Floodway•
AA. g-.—"Functionally Dependent Use" means a use which cannot perform its intended purpose unless it is
located or carried out in close proximity to water.The term includes only docking facilities, port facilities that are
necessary for the loading and unloading of cargo or passengers, and ship building and ship repair facilities, and
does not include long-term storage or related manufacturing facilities.
BB. "Highest adjacent grade" means the highest natural elevation of the ground surface prior to
construction next to the proposed walls of a structure.
SCC. "Historic structure" means aany structure that is:
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1. . Is listed on . Listed individually in the National Register of Historic Places,the Washington
been issued Sa - • - - - --- et _ -- - - - • - - - :-•• - -• - e.•-•--.listing
maintained by the Department of Interior) or preliminarily determined by the Secretary of the Interior as
meeting the requirements for individual listing on the National Regster;
2. . Has been certified to contribute. Certified or preliminarily determined by the Secretary of the
Interior as contributing to the historical significance of a registered historic district or a district
preliminarily determined by the Secretary to qualify as a registered historic district
3. SIndividually listed on a state inventory of historic places in states with historic preservation
programs which have been approved by the Secretary of Interior; or
4. Individually listed on a local inventory of historic places in communities with historic
preservation programs that have been certified either:
a. By an approved state program as determined by the Secretary of the Interior, or
b. Directly by the Secretary of the Interior in states without approved programs.
AA:DD. "Hyporheic zone" means a saturated layer of rock or sediment beneath and/or adjacent to a stream
channel that contains some proportion of channel water or that has been altered by channel water infiltration.
-13B,EE. "Impervious surface"means a taardnon-vegetated surface area which 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 which similarly impede the
natural infiltration of stormwater.
CC.FF. t "Lowest floor" means the lowest floor of the lowest enclosed area (including basement) measured
. .. __ _ •- e e .An unfinished or flood-resistant enclosure, usable solely for parking of
vehicles, building access,or storage;in an area other than a basement area is not considered a building's
lowest floor as long acprovided that such enclosure is not built so as to render the structure in violation of the
applicable non:elevation design requirements of this chapter found in ACC 15.68.170(A)(7)-(i.e. provided there
are adequate flood ventilation openings).
t3�GG.1/21- -"Manufactured home" means a structure, transportable in one or more sections,which is built on a
permanent chassis and is designed for use with or without a permanent foundation when connectedattached to
the required utilities. e .• •• •-••-• - •• - - •• "• - • -- - - • - -- - -e - e-
__ .•-- -*-• e- ___ , •-The term "manufactured home"does not include e- - -, - - - -
a"recreational v les.vehicle."
€E HH. W:"Manufactured home park or subdivision" means a parcel (or contiguous parcels)of land divided
into two or more manufactured home lots for rent or sale.
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II. K—"Market value" shall mean the current assessed value as established by the most recent tax roll of
the county assessor in which the property is located.An applicant may, at applicant's expense, provide an
appraisal to determine market value.
"Mean Sea Level" means for purposes of the National Flood Insurance Program,the vertical datum to
which Base Flood Elevations shown on a community's Flood Insurance Rate Map are referenced.
GG.KK. --"Native vegetation" means plant species that are indigenous to the community's area and that
reasonably could be expected to naturally occur on the site.
i +LL. °'Natural floodplain functions" means the contribution that a floodplain makes to support habitat,
including, but not limited to, providing flood storage and conveyance, reducing flood velocities, reducing
sedimentation,filtering nutrients and impurities from runoff, processing organic wastes, moderating
temperature fluctuations, and providing breeding and feeding grounds, shelter, and refugia,for aquatic or
riparian species.
AMM. AA—"New construction" means for the purposes of determining insurance rates, structures for which
the"start of construction" commenced on or after the effective date of an initial Flood Insurance Rate Map or
after December 31, 1974,whichever is later, and includes any subsequent improvements to such structures.
For floodplain management purposes, "new construction" means structures for which the"start of construction"
commenced on or after the effective date of the ordinance adopted by a community and includes any
subsequent improvements to such structures .
NN. tom--"Principal Structure" means a structure in which the principal use of the lot on which it is located is
conducted.
JJ OO. "Protected area" means the lands that lie within the boundaries of the floodway,the riparian
#habitatbuffer zone, and the channel migration area. • - •- - •- - - '--- •• -
boundariesBecause of the 'e- -- - , •- - - - ••.e - -• -, - •- - - "impact that
development can have on flood heights and velocities and habitat, special rules apply in the Protected Area.
PP. CC. "Reasonably Safe from Flooding" means development that is designed and built to be safe from
flooding based on consideration of current flood elevation studies, historical data, high water marks and other
reliable data known to the community. In unnumbered A zones where flood elevation information is not
available and cannot be obtained by practicable means, reasonably safe from flooding means that the lowest
floor is at least two feet above the Highest Adjacent Grade.
KK QQ. "Recreational vehicle" means a vehicle:
1. —Built on a single chassis; and,
2. —Four hundred square feet or less when measured at the largest horizontal projection; and,
3. . Designed to be self-propelled or permanently towable by a-an automobile or light-duty
truck; and,
4. —Designed primarily not for use as a permanent dwelling but as temporary living quarters
for recFeationrecreational, camping, travel;or seasonal use.
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LL. DD. "Regulatory floodplain"means the area of the special flood hazard area and all protected areae
MAPA-RR.EE. "Riparian" means of, adjacent to, or living on,the bank of a stream, lake, pond, sound, or other
water body.
SS. FF. "Riparian habitat zone"Riparian buffer zone" means the land located adjacent to streams, and
other bodies of water,where the natural soil, hydrology, and native flora and fauna perform important
ecological functions such as protecting the water body by filtering out pollutants, preventing erosion and
sedimentation, stabilizing stream banks,and providing natural shade.They are often thin lines-of-green
containing native grasses,flowers, shrubs and trees that line the banks of streams and other bodies of water.
The riparian buffer zone for the Puget Sound Biological Opinion applies only to areas mapped within the
Special Flood Hazard Area, unless the area is undeveloped with predominately native vegetation that have
benefits to endangered species, in which case the regulations for riparian habitat zones shall apply.
NN:TT. "Riparian Habitat Zone"means the water body and adjacent land areas that are likely to support
aquatic and riparian habitat -- - - ' - •- - • •- - -•- -- • • "- - -
00. 1. Marine and lake shorelines and Type S streams that arc designated"shorelines of the state": 250
feet.
UU .• GG. "Special flood hazard area (SFHA)" means the land subject to inundation by the base flood.
Special flood hazard areas are .e•• - - •' - •' - ''-•-t••••• - • --
• ' •, •• , - _ • - _ - •- - i - ' -.- • - - - -- - - _ - --- , • - -
flood insurance rate maps with the letter A, including AE, AO,AH,Al 99.designated on Flood Insurance Rate
Maps with the letters"A"or"V" include AE(floodway),AO, AH, Al-99 and VE.The Special Flood Hazard Area
is also referred to as the area of special flood hazard or SFHA.
VV. HH. "Start of construction"includes substantial improvement, and means the date the building permit
was issued, provided the actual start of construction, repair, reconstruction, rehabilitation, addition, placement
or other improvement was within 180 days of the perm it'scpiration date of the permit.
The"actual start! means either the first placement of permanent construction of a structure on a site, such as
the pouring of slab or footings,the installation of piles,the construction of columns, or any work beyond the
stage of excavation; or the placement of a manufactured home on a foundation.=Permanent construction does
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not include land preparation, such as clearing, grading and filling; nor does it include the installation of streets
and/or walkways; nor does it include excavation for a basement,footings, piers, or foundations or the erection
of temporary forms; nor does it include the installation on the property of accessory buildings, such as garages
or sheds not occupied as dwelling units or not part of the main structure._For a substantial improvement,the
"actual_start of construction" means the first alteration of any wall, ceiling,floor, or other structural part of a
building,whether or not that alteration affects the external dimensions of the building.
WW. 44—"Structure" means a walled and roofed building,including a gas or liquid storage tank,that is
principally above ground, as well as a manufactured home.
XX. d,4 "Substantial damage" means damage of any origin sustained by a structure whereby the cost of
restoring the structure to its before-damaged condition would equal or exceed 50 percent of the market value of
the structure before the damage occurred,
YY. KK. "Substantial improvement"ar-4,419stantially-impfevedL.means any repair, reconstruction,
rehabilitation, addition, replacement or improvement of a structure,the cost of which equals or exceeds 50
percent of the • - • - - - -- - -- - ' - - • • - - - - -- -• - - - . ..
- - - -- - ' - - -- - - - -- - - • -- -- -market
value of the structure before the"start of construction"of the improvement. This term includes structures which
have incurred "substantial damaqe,"regardless of the actual repair work performed.
The term does not, however, include either:
1. . _Any project for improvement of a structure to correct existing violations of state or local
health, sanitary, or safety code specifications that have been identified by the local code enforcement
official and that are the minimum necessary to assure safe living conditions; or
2. —Any alteration of a"historic structure" provided that the alteration will not preclude the
structure's continued designation as a"historic structure". - -• •- - .e•- - — .-
ZZ. -LL- "Variance"means a grant of relief from the requirements of this ehapterordinance which permits
construction in a manner that would otherwise be prohibited by this cbapterordinance.
AAA. MM. "Violation" means the failure of a structure or other development to be constructed or
implemented in conformance with the community's applicable floodplain development regulations.
AAA,BBB. "Water typing" means a system for classifying water bodies according to their size and fish
habitat characteristics. The Washington Department of Natural Resources Forest Practices Water Typing
Classification System is hereby adopted by reference. The system defines four water types:
1. . _Type"S"-_–Shoreline: Streams that are designated"shorelines of the state," including
marine shorelines.
2. _Type"F"-_–Fish: Streams that are known to be used by fish or meet the physical criteria to
be potentially used by fish.
3. _Type"44PL-Np"-Non-fish perennial streams.
4. _Type"P1-. Ns"–Non-fish seasonal streams.
BBBCCC. NN. "Zone"means one or more areas delineated on the FIRM. The following zones may be
used on the adopted FIRM. The special flood hazard area is comprised of the A Zone.and V Zones.
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1. —A: SFHA where no base flood elevation is provided.
2. . A#: Numbered A zones(e.g., A7 or A14), SFHA with a base flood elevation.
3,2. —AE: SFHA with a base flood elevation.
4.3. —AO: SFHA subject to inundation by shallow flooding usually resulting from sheet flow on
sloping terrain, with average depths between one and three feet.Average flood depths are shown.
4. . _AH: SFHA subject to inundation by shallow flooding (usually areas of ponding)with
average depths between one and three feet. Base flood elevations are shown.
6. . B: The area between the SFHA and the 500 year flood of the primary source of flooding. It
7. . C:An area of minimal flood hazard, as above the 500 y ar flood level of the primary source
Area of undetermined but possible flood hazard.
9-6. —X: The area outside the mapped SFHA with a low risk of flooding.
7. —Shaded X: An area of moderate risk of flooding from the base flood, and defined as:
a. areas of shallow(i.e., less than 1 foot)flooding;
b. 0.2%chance(or 500-year)flooding;
c. has a drainage area less than 1 sq. mile; or
a-d.areas protected by a levee. •- -. •- - - •- - - -- - e - . - - .
Section 3. Regulatory Data
15.68.070 Land110 Area to be Regulated.
• -_ - -.e _ • "e- . . _e__ -'• The area to be regulated is comprised of the Special Flood
Hazard Area and all Protected Areas within the Special Flood Hazard Area within the jurisdiction of the city-
(See-the-cityCity of Auburn -e- - ':e:e - • -. _ - • •- - - e •- _ . . The term also
includes areas delineated pursuant to the provicions of Chapter 1.25 ACC. Section 15.68.150.
-15.68.120 Special Flood Hazard Area.
Basis for Establishing the Areas of Special Flood Hazard
A. The special flood hazard areas identified by the Federal Insurance Administrator in a scientific and
engineering report entitled"The Flood Insurance Study(FIS)for King County Washington and Incorporated
Areas"dated August 19, 2020,and any revisions thereto,with accompanying Flood Insurance Rate Maps
(FIRMs)dated August 19, 2020, and any revisions thereto,as well as the special flood hazard areas identified
by the Federal Insurance Administrator in a scientific and engineering report entitled"The Flood Insurance
Study(FIS)for Pierce County Washington and Incorporated Areas" dated March 7, 2017,and any revisions
thereto,with accompanying Flood Insurance Rate Maps(FIRMs) dated March 7, 2017, and any revisions
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thereto,are hereby adopted by reference and declared to be a part of this ordinance. The FIS and the FIRM
are on file at 1 East Main St,Auburn,WA 98001.
A:B. The best available information for flood hazard area identification as outlined in Section 15.68.130(D)
shall be the basis for regulation until a new FIRM is issued that incorporates data utilized under Section
15.68.130(D).
8. 15.68.110 Interpretation.
C. Upon receipt of a floodplain development permit application,the floodplain administrator or designee
shall compare the elevation of the site to the base flood elevation.
C D. The floodplain administrator or designee shall inform the applicant that the project may still be subject
to the flood insurance purchase requirements unless the owner receives a Letter of Map Amendment(LOMA)
from FEMA.
E. The floodplain administrator or designee shall make interpretations where needed, as to the exact
locations of the boundaries of the SFHA and the Protected Area (e.g.where there appears to be a conflict
between the mapped SFHA boundary and actual field conditions as determined by the base flood elevation and
ground elevations) as it applies to proposed development.The applicant may appeal the floodplain
administrator's or designee's interpretation of the location of the boundary to the
Hearing Examiner for the City of Auburn.
15.68.130 Flood Hazard Data.
A. The base flood elevation for the SFHAs incorporated in 15.68.120(A)shall be utilized.
B. The Flood Protection Elevation (FPE) shall be the base flood elevation plus one (1)foot.
C. The floodway shall be as delineated on the Flood Insurance Rate Map_
D. Where base flood elevation and floodway data have not been provided in Special Flood Hazard Areas,
the floodplain administrator or designee shall obtain, review and reasonably utilize any base flood elevation and
floodway data available from a Federal, State or other source.
15.68.140 Protected Area.
A. The Protected Area is comprised of those lands that lie within the boundaries of the floodway,the
riparian habitat buffer zone, and the channel migration area.
B. In riverine areas,where a floodway has been designated in accordance with Sections 15.68.130:(C),
15.68.130(D)or 15.68.150(-E),the Protected Area is comprised of those lands that lie within the boundaries of
the riparian habitat buffer zone, the channel migration area, and the SFHA,
C. Riparian Buffer Zone: The riparian buffer zone includes those watercourses within the SFHA and
adjacent land areas that are likely to support aquatic and riparian habitat.
1. The size and location of the riparian buffer zone is dependent on the type of water body. The
riparian buffer zone includes the water body and adjacent lands, measured perpendicularly from
ordinary high water mark on both sides of the water body:
a. Type S streams that are designated"shorelines of the State:"—250 feet
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b. Type F streams (fish bearing) streams greater than 5 feet wide and marine
shorelines:—200 feet
c. Type F streams less than 5 feet wide and lakes:—150 feet
d. Type N (nonsalmonid-bearing)perennial and seasonal streams with unstable slopes:
225 feet
e. All other Type N (nonsalmonid-bearing) perennial and seasonal streams:-150 feet.
2. The riparian buffer zone shall be delineated on the site plan by the applicant at the time of
application for subdivision approval or floodplain development permit for all development proposals
within 300 feet of any stream or shoreline.
D. Channel Migration Area:
a. The channel migration area shall be the channel migration zone as defined in Section
15.68.100(K).
b. Where more than one channel migration zone has been delineated,the floodplain
administrator or designee shall use the delineation that has been adopted for other local
regulatory purposes.
a c. Where a channel migration zone has not yet been mapped, the provisions shall be:of
Section 15.68.150-(D)shall apply at the time of permit application.
15.68.150 New Regulatory Data.
A. All requests to revise or change the flood hazard data, including requests for a Letter of Map Revision
and a Conditional Letter of Map Revision shall be reviewed by the floodplain administrator or designee.
1. The floodplain administrator or designee shall not sign the Community Acknowledgment Form
for any requests based on filling or other development, unless the applicant for the letter documents
that such filling or development is in compliance with this ordinance.
2. The floodplain administrator or designee shall not approve a request to revise or change a
floodway delineation until FEMA has issued a Conditional Letter of Map Revision that approves the
change.
B. If an applicant disagrees with the regulatory data prescribed by this ordinance, he/she may submit a
detailed technical study needed to replace existing data with better data in accordance with FEMA mapping
guidelines or Regional Guidance for Hydrologic and Hydraulic Studies in Support of the Model Ordinance for
Floodplain Management under the National Flood Insurance Program and Endangered Species Act FEMA
Region X, 2010. If the data in question are shown on the published FIRM, the submittal must also include a
request to FEMA for a Conditional Letter of Map Revision.
C. Where base flood elevation data are not available in accordance with Section 15.68.130,applicants for
approval of new subdivisions and other proposed developments(including proposals for manufactured home
parks)greater than 50 lots or 5 acres, whichever is the lesser, shall include such data with their permit
applications.
D. Where channel migration zone data are not available in accordance with 15.68.140(D),the permit
applicant shall either:
1. Designate the entire SFHA as the channel migration zone or
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2. Identify the channel migration area in accordance with Regional Guidance for Hydrologic and
Hydraulic Studies in Support of the Model Ordinance for Floodplain Management under the National
Flood Insurance Program and Endangered Species Act FEMA Region X, 2012.
E. All new hydrologic and hydraulic flood studies conducted pursuant to Section 15.68.150 shall be in
accordance with Regional Guidance for Hydrologic and Hydraulic Studies in Support of the Model Ordinance
for Floodplain Management under the National Flood Insurance Program and the Endangered Species Act,
FEMA, Region X, 2010.
F. The floodplain administrator shall use the most restrictive data available prepared specifically for the
project site for the channel migration zone,floodways,future conditions, and riparian buffer zone.
Section 4.Administration
15.68.160 Establishment of Floodplain Development Permit
A floodplain development permit shall be obtained before construction or development begins within the
Special Flood Hazard Area(SFHA)or Protected Area. The permit shall be for all development as set forth in
15.68.170 Floodplain Development Permit Application.
Applications for a floodplain development permit shall be made using the criteria outlined in the Floodplain
Development Application Packet available for download at www.auburnwa.gov/forms. At a minimum,the
following information is required.
A. Proposed elevation in relation to mean sea level,of the lowest floor(including basement)of all
structures recorded on a current elevation certificate with Section B completed by the Floodplain Administrator.
B. Proposed elevation in relation to mean sea level to which any structure will be flood proofed,
C. Where a structure is to be flood proofed, certification by a registered professional engineer or architect
that the flood proofing methods for any nonresidential structure meet flood proofing criteria in Section 5,
D. Description of the extent to which a watercourse will be altered or relocated as a result of proposed
development;
E. Where development is proposed in a floodway, an engineering analysis indicating no rise of the Base
Flood Elevation; and
F. Any other such information that may be reasonably required by the Floodplain Administrator in order to
review the application.
15.68.180 Floodplain Development Permit Expiration.
If there has been no start of construction, a floodplain development permit shall expire 180 days after the date
of issuance.Where the applicant documents a need for an extension beyond this period due to conditions
beyond the applicant's control,the floodplain administrator A or designee may authorize one or more
extensions.
15.68.190 Designation of the Floodplain Administrator.
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The Director of Community Development is hereby appointed to administer, interpret, implement, and enforce
this ordinance by granting or denying floodplain development permit applications in accordance with its
provision. The Director of Community Development may designate administration of portions or all of this
ordinance to a qualified person.
15.68.200 Duties of the Floodplain Administrator.
Duties of the floodplain administrator or designee shall include, but are not limited to:
A. Review all floodplain development permits to determine that the permit requirements of this ordinance
have been satisfied.
B. Review all floodplain development permits to determine that all necessary permits have been obtained
from those Federal, State or local government agencies from which prior approval is required, including those
local, State or Federal permits that may be required to assure compliance with the Endangered Species Act
and/or other appropriate State or Federal laws.
C. Review all floodplain development permits to determine if the proposed development is located in the
Protected Area. If located in the Protected Area,ensure that the provisions of Section 7 are met.
D. Ensure that all development activities within the Special Flood Hazard Area of the jurisdiction of the
City meet the requirements of the ordinance.
E. Inspect all development projects before, during and after construction to ensure compliance with all
provisions of this ordinance, including proper elevation of the structure.
F. Maintain for public inspection all records pertaining to the provisions of this ordinance.
G. Submit reports to include the projects for which they issue floodplain development permits, including
effects to flood storage,fish habitat, and all indirect effects of development and mitigation provided to FEMA as
required by the National Flood Insurance Program.
H. Notify FEMA of any proposed amendments to this ordinance and when annexations occur in the
Special Flood Hazard Area.
Ensure the proposed development is not located in the floodway. If located in the floodway, assure the
encroachment provisions of Section 15.68.410 are met
J. Cooperate with State and Federal agencies to improve flood and other technical data and notify FEMA
of any new data that would revise the FIRM.
K. Review all floodplain development permits to verify that proposed development will be reasonably safe
from flooding.
15.68.210 Notification to Other Entities
Whenever a watercourse is to be altered or relocated:
A. Notify adjacent communities and the Department of Ecology prior to such alteration or relocation of a
watercourse, and submit evidence of such notification to the Federal Insurance Administrator through
appropriate notification means,and
B. Assure that the flood carrying capacity of the altered or relocated portion of said watercourse is
maintained.
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15.68.220 Records.
A. Where base flood elevation data have been obtained pursuant to Section 15.68.130 and 15.68.150,
the floodplain administrator or designee shall obtain, record, and maintain the actual"finished construction"
elevations provided by the applicant for the locations listed in Section 15.68.170. This information shall be
recorded on a current FEMA Elevation Certificate signed and sealed by a professional land surveyor,currently
licensed in the State of Washington.
B. For all new or substantially improved dry floodproofed nonresidential structures,where base flood
elevation data has been obtained pursuant to Section 15.68.130 and 15.68.150,the floodplain administrator or
designee shall obtain, record and maintain the elevation (in relation to the datum of the effective FIRM)to
which the structure was floodproofed. This information shall be recorded on a current FEMA Floodproofinq
Certificate by a professional engineer currently licensed in the State of Washington.
C. Certification required by Section 15.68.410 (floodway encroachments).
D. Records of all variance actions, including justification for their issuance.
E. Improvement and damage calculations.
F. Maintain for public inspection all records pertaining to the provisions of this ordinance.
15.68.230 Certificate of Occupancy.
A. A final grading and/or storm permit for the property, physical completion for City of Auburn Capital
Improvement projects without a building, a certificate of occupancy (commercial building) or final building
inspection (residential structure)for a new or substantially improved structure or an addition shall not be issued
until:
1. The permit applicant provides a properly completed, signed and sealed Elevation or
Floodproofinq Certificate showing finished construction data as required by Section 15.68.220,
2. If a mitigation plan is required by Sections 15.68.440 and 15.68.450, all work identified in the
plan has been completed according to the plan's schedule;
3. The applicant provides copies of all required Federal, State,and local permits noted in the
permit application per Section 15.68.170,
4. All other provisions of this ordinance and conditions placed on the floodplain development
permit approval letter have been met.
15.68.240 - -e'- - - - e e " -- - • - ---
contrary information provided on a map. (Ord. 6295§2, 2010; Ord.6161 §-1, 2008; Ord. 4820§ 1, 1995; Ord.
4357§2 (3.5), 1989.}
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15.68.120 Warning and disclaimer of liability.
• • ! .. - - • , 9 .. - , -
§2(3.6), 1989.)
15.68.125 Appeals.
A. The Hearing Examiner, as established by Chapter 2.46 of the Auburn City Code,shall hear and decide
appeals and requests for variances from the requirements of this chapter ordinance.
B. The Hearing Examiner shall hear and decide appeals when it is alleged there is an error in any
requirement,decision, or determination made by the floodplain administrator or designee in the enforcement or
administration of this chapter-ordinance.
C. Those aggrieved by the decision of the Hearing Examiner may appeal euchthe decision to the superior
court-of the county in which the project is located pursuant to Section 2.46.160 of the Auburn City Code.
D. Upon consideration of the factors of this-GlaapterSection 15.68.250 and the purposes of this
shapterordinance,the Hearing Examiner may attach such conditions to the granting of the
variances as+the/she deems necessary to further the purposes of this chapter-ordinance.
E. The floodplain administrator or designee shall maintain the records of all appeal actions and report any
variances to the Federal Emergency Management Agency upon request.
15.68. -! - -- •-.••-' - - --. -•' • - -- '.--- •250 Variance Criteria.
A. In addition to theCriteria outlined in ACC 18.70.025, in reviewing applications for a variance,the
Hearing Examiner shall consider all technical evaluations,all relevant factors, standards specified in other
sections of this ordinance; and:
1. The relationship of the proposed use to the comprehensive plan, growth management
regulations,critical area regulations,the shoreline management program and floodplain management
program for the area,
4-2. The potential of the proposed development permit project to destroy or adversely affect a fish
and wildlife habitat conservation area or create an adverse effect to federal, state or locally protected
species or habitat;
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3. . °---- . . . .... . . .. Is the minimum necessary to grant relief; and,
B. In addition to the Criteria outlined in ACC 18.70.025, no variance shall be granted to
the requirements of this ordinance unless the applicant demonstrates that:
1. The project will not adversely affect features or quality of habitat supporting local, state or
federally protected fish or wildlife,
C. Variances may be requested for new construction , substantial improvements,
and other development upon showing of good and sufficient cause and is minimum necessary, considering
flood hazard, to afford relief provided:
D. Variances shall only be issued:
1. Upon a determination that the granting of a variance will not result in increased flood heights,
additional threats to public safety, extraordinary public expense, create nuisances, cause
fraud on or victimization of the public, or conflict with existing local laws or ordinances,
2. For the repair, rehabilitation, or restoration of historic structures upon a determination that the
proposed repair or rehabilitation will not preclude the structure's continued designation as a
historic structure and the variance is the minimum necessary to preserve the historic character
and design of the structure;
3. Upon a determination that failure to grant the variance would result in exceptional hardship to
the applicant,
4. Upon a showing that the use cannot perform its intended purpose unless it is located or
carried out in close proximity to water. This includes only facilities defined in Section 2 of this
ordinance in the definition of"Functionally Dependent Use."
E. Variances shall not be issued within any floodway if any increase in flood levels during the base flood
discharge would result.
F. Generally, variances may be issued for new construction and substantial improvements to be erected
on a lot of one-half acre or less in size contiguous to and surrounded by lots with existing structures
constructed below the BFE, provided the procedures of Sections 4 and 5 of this ordinance have been fully
considered.As the lot size increases beyond one-half acre, the technical justification required for issuing the
variance increases.
G. In considering variance applications, the City of Auburn shall consider all technical evaluations, all
relevant factors, all standards specified in other sections of this ordinance, and:
1. The danger that materials may be swept onto other lands to the injury of others;
2. The danger to life and property due to flooding or erosion damage;
3. The susceptibility of the proposed facility and its contents to flood damage and the effect of
such damage on the individual owner,
4. The importance of the services provided by the proposed facility to the community;
5. The necessity to the facility of a waterfront location, where applicable;
6. The availability of alternative locations for the proposed use, which are not subject to flooding
or erosion damage,
7. The compatibility of the proposed use with existing and anticipated development;
23
8. The relationship of the proposed use to the comprehensive plan and floodplain management
program for that area.,
9. The safety of access to the property in time of flood for ordinary and emergency vehicles.,
10. The expected heights,velocity, duration, rate of rise, and sediment transport of the
floodwaters expected at the site.,
11. The costs of providing governmental services during and after flood conditions, including
maintenance and repair of public utilities and facilities, such as sewer, gas, electrical, water system,
and streets and bridges,
H. Any applicant to whom a variance is granted shall be given written notice over the signature of a
community official that:
1. The issuance of a variance to construct a structure below the Base Flood Elevation will result
in increased premium rates for flood insurance up to amounts as high as$25 for$100 of insurance
coverage, and
2. Such construction below the base flood elevation increases risks to life and property.
I. The Floodplain Administrator shall maintain a record of all variance actions, including justification for
their issuance.
Section 5.General Development Standards
The provisions of Section 5 shall apply in the Special Flood Hazard Area:
15.68.260 Development and Subdivision Proposals.
This section applies to all development proposals including commercial development, subdivisions, short
subdivisions, preliminary subdivisions, binding site plans,and expansions to manufactured home parks as
defined in Chapter 17.04 ACC.
A. All development proposals shall be consistent with the need to minimize flood damage.
B. All development proposals shall have utilities and facilities, such as sewer, gas, electrical, and water
systems located and constructed to prevent flood damage.
C. All development proposals shall have adequate drainage provided to avoid exposure to water damage.
D. The proposed subdivision must have one or more new lots in the Special Flood Hazard Area set aside
for open space use through deed restriction, easement, subdivision covenant, or donation to a public agency.
1. In the Special Flood Hazard Area outside the Protected Area,zoning must maintain a low
density of floodplain development.
2. In the Special Flood Hazard Area outside the protected area in which the current zoning is
less than 5 acres must maintain current zoning.
3. The density of development in the portion of the development outside the Special Flood
Hazard Area may be increased to compensate for the amount of land in the Special Flood Hazard
Area preserved as open space in accordance with Chapter 17.25 ACC.
E. If a parcel has a buildable site outside the Special Flood Hazard Area, it shall not be subdivided to
create a new lot that does not have a buildable site outside of the Special Flood Hazard Area. This provision
does not apply to tracts that are to be preserved as open space.
24
F. All development proposals shall ensure that all subdivisions have at least one access road connected
to land outside the Special Flood Hazard Area with the surface of the road at or above the FPE wherever
possible.-Additional access roads may be required based on the number of proposed lots per the current City
of Auburn Engineering Design Standards.
G. The final recorded plat shall include a notice that part of the property is in the SFHA, riparian buffer
zone and/or channel migration area, as appropriate.
H. BFE generation for all development proposals greater than 50 lots or 5 acres,whichever is the lesser.
15.68.270 Site Design.
A. Structures and other development shall be located to avoid flood damage or that adequately mitigates
any identified impacts.
1. If a lot has a buildable site out of the Special Flood Hazard Area, all new structures shall be
located in that area,when possible.
2. If a lot does not have a buildable site out of the Special Flood Hazard Area, all new structures,
pavement, and other development must be sited in the location that has the least impact on habitat by
locating the development as far from the water body as possible or by placing the structure on the
highest portion of the lot.
3. A minimum setback of 15 feet from the Protected Area shall be required for all structures.
4. If the proposed project does not meet the criteria of Section 15.68.270(-A)through (B), a
habitat impact assessment shall be conducted pursuant to Section 15.68.440 and, if necessary, a
habitat mitigation plan shall be prepared and implemented pursuant to Section 15.68.450.
B. All new development shall be designed and located to minimize the impact on flood flows,flood
storage,water quality and habitat.
1. Stormwater and drainage features shall incorporate low impact development techniques, if
technically feasible,that mimic pre-development hydrologic conditions, such as stormwater infiltration,
rain gardens, grass swales,filter strips,disconnected hard surface areas, permeable pavement,
vegetative roof systems, etc. per the City's current SWMM per Chapter 12.04 ACC.
2. If the proposed project will create new hard surfaces so that more than 10 percent of the
portion of the lot in the Special Flood Hazard Area is covered by hard surface,the applicant shall
demonstrate that there will be no net increase in the rate and volume of the stormwater surface runoff
per the maximum extent feasible and as required per the City's current SWMM per ACC 13.48 that
leaves the site or that the adverse impact is mitigated, as provided in Sections 15.68.440 and
15.68.450.
C. The site plan required in Section 15.68.170—shall account for surface drainage to ensure that:
1. Existing and new buildings on the site will be protected from stormwater runoff;and
2. The project will not divert or increase surface water runoff onto neighboring properties.
15.68.280 Hazardous Materials.
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A. No new development shall create a threat to public health, public safety or water quality. Chemicals,
explosives, gasoline, propane, buoyant materials, animal wastes,fertilizers,flammable liquids, pollutants, or
other materials that are hazardous,toxic, or a threat to water quality are prohibited from the Special Flood
Hazard Area. This prohibition does not apply to small quantities of these materials kept for normal household
use. This prohibition does not apply to the continued operations of existing facilities and structure, reuse of
existing facilities and structures, or functionally dependent facilities or structures.
B. If the proposed project cannot meet Section 15.68.280(A)of this ordinance,then a habitat impact
assessment must be conducted in accordance with Sections 15.68.440 and 15.68.450.
15.68.290 Critical Facilities.
A. Construction of new critical facilities shall be,to the extent possible, located outside the limits of the
Special Flood Hazard Area.
B. Construction of new critical facilities in the Special Flood Hazard Area shall be permissible if no
feasible alternative site is available, provided;
1. Critical facilities shall have the lowest floor elevated three feet above the base flood elevation
or to the height of the 500-year flood,whichever is higher. If there is no available data on the 500-year
flood,the permit applicants shall develop the needed data in accordance with FEMA mapping
guidelines. . • -• - --••-• - -•• •• --- -
. Access to and from the -- -••-• - -- - --- - --•critical
facility shall be shown-to--be:
2. 1. Outside the protected area;
�2. 2. Highcr thanto the elevation of the 500-year floodplain.—Access routes elevated to or
above the level of the base flood elevation shall be provided to all critical facilities to the extent
possible.
Section 6. Standards for Protection of Structures
15.68.300 Applicability.
The protection requirements in this section apply to all new structures and substantial improvements,which
include:
A. Construction or placement of a new structure.
B. Reconstruction, rehabilitation, or other improvement that will result in a substantially improved building.
C. Repairs to an existing building that has been substantially damaged regardless of the actual repair
work that is done .
D. Placing a manufactured home on a site.
E. Placing an occupied recreational vehicle or travel trailer on a site for more than 180 days.
15.68.310 Flood Protection Standards.
A. All new structures and substantial improvements shall have the lowest floor, including basement,
elevated to or above the FPE.
26
B. New construction and substantial improvement of any residential structure in an Unnumbered A zone
for which a BFE is not available and cannot be reasonably obtained shall be reasonably safe from flooding, but
in all cases the lowest floor shall be at least two feet above the Highest Adjacent Grade.
C. The structure shall be aligned parallel with the direction of flood flows where practicable.
D. The structure shall be anchored to prevent flotation, collapse, or lateral movement of the structure
resulting from hydrodynamic and hydrostatic loads including the effects of buoyancy.
E. All manufactured homes shall be anchored to prevent flotation, collapse, or lateral movement, and
shall be installed using methods and practices that minimize flood damage. Anchoring methods may include,
but are not limited to, use of over-the-top or frame ties to ground anchors.
F. All materials below the FPE shall be resistant to flood damage and firmly anchored to prevent flotation.
Materials harmful to aquatic wildlife, such as creosote, are prohibited below the FPE.
G. All new construction and substantial improvements shall be constructed using methods and practices
that minimize flood damage
H. Electrical, heating,ventilation,duct work, plumbing, and air-conditioning equipment and other service
facilities shall be elevated to or above the FPE.Water, sewage, electrical, and other utility lines(excluding
storm drainage facilities) below the FPE shall be constructed so as to minimize water from entering or
accumulating within them during conditioning of flooding.
Fully enclosed areas below the lowest floor that are subject to flooding shall be used only for parking,
limited storage,or building access and shall be designed to automatically equalize hydrostatic flood forces on
exterior walls by allowing for the entry and exit of floodwaters. Designs for meeting this requirement shall either
be certified by a registered professional engineer or licensed architect in the State of Washington and/or meet
or exceed the following minimum criteria:
1. A minimum of two openings having a total net area not less than one square inch for every
square foot of enclosed area subject to
flooding shall be provided.
2. The bottom of all openings shall be no higher than one foot above grade.
3. Openings may be equipped with screens, louvers, or other coverings or devices provided that
they permit the automatic entry and exit of floodwaters.
4. A garage attached to a residential structure,constructed with the garage floor slab below the
BFE, must be designed to allow for the automatic entry and exit of flood waters.
15.68.320 Nonresidential Construction.
New construction and substantial improvement of any commercial,industrial, or other nonresidential structure
shall—meet the requirements of subsection A or B below:
A. New construction and substantial improvement of any commercial, industrial or other nonresidential
structure shall meet all of the following requirements:
1. New construction and substantial improvement of any commercial, industrial, or other
nonresidential structure shall have the lowest floor, including basement, elevated one foot or more
above the BFE, or elevated as required by ASCE 24,whichever is greater. Mechanical equipment and
27
utilities shall be waterproofed or elevated least one foot above the BFE, or as required by ASCE 24,
whichever is greater.
2. If located in an Unnumbered A zone for which a BFE is not available and cannot be
reasonably obtained,the structure shall be reasonably safe from flooding, but in all cases the lowest
floor shall be at least two feet above the Highest Adiacent Grade.
3. If buildings are constructed or substantially improved with fully enclosed areas below the
lowest floor,that are subject to flooding,the areas shall be used only for parking, limited storage, or
building access, and shall be designed to automatically equalize hydrostatic flood forces on exterior
walls by allowing for the entry and exit of floodwaters. Designs for meeting this requirement must either
be certified by a registered professional engineer or architect or must meet or exceed the following
minimum criteria:
a. Have a minimum of two openings with a total net area of not less than one square
inch for every square foot of enclosed area subject to flooding.
b. The bottom of all openings shall be no higher than one foot above grade.
c. Openings may be equipped with screens, louvers, valves, or other coverings or
devices provided that they permit the automatic entry and exit of floodwater.
4. Alternatively, a registered engineer or architect may design and certify engineered openings.
B. If the requirements of Section 15.68.320(A)are not met,then new construction and substantial
improvement of any commercial, industrial or other nonresidential structure shall meet all of the following
requirements:
1. Together with attendant utility and sanitary facilities, be dry floodproofed so that below one
foot or more above the base flood level the structure is watertight with walls substantially impermeable
to the passage of water or dry floodproofed to the elevation required by ASCE 24,whichever is
greater,
2. Have structural components capable of resisting hydrostatic and hydrodynamic loads and
effects of buoyancy,
3. Be certified by a registered professional engineer or architect that the design and methods of
construction are in accordance with accepted standards of practice for meeting provisions of this
subsection based on their development and/or review of the structural design, specifications and
plans. Such certifications shall be provided to the official as set forth in Section 15.68.220(B),
15.68.330 Manufactured Homes.
All manufactured homes to be placed or substantially improved on sites shall be:
A. Elevated on a permanent foundation in accordance with Section 15.68.310(A) and
B. Securely anchored to an adequately anchored foundation system to resist flotation, collapse and
lateral movement. Methods of anchoring may include, but are not to be limited to, use of over-the-top or frame
ties to ground anchors. This requirement is in addition to other applicable anchoring requirements for resisting
wind forces.
28
C. If manufactured homes are constructed or substantially improved with fully enclosed areas below
the lowest floor,the areas shall be used solely for parking of vehicles, building access, or storage.
15.68.340 Recreational Vehicles.
Recreational vehicles placed on sites shall:
A. Be on the site for fewer than 180 consecutive days,or
B. Be fully licensed and ready for highway use, on their wheels or lacking system, attached to the site
only by quick disconnect type utilities and security devices, and have no permanently attached addition; or
C. Meet the requirements of Section 15.68.340 and the anchoring requirements for manufactured homes
in Section 15.68.330.
15.68.350 Appurtenant Structures.
A structure which is on the same parcel of property as the principle structure and the use of which is incidental
to the use of the principle structure and is not used for human habitation may be exempt from the elevation
requirements of Section 15.68.310-(A), provided:
A. It is used only for parking or storage;
B. It is constructed and placed on the building site so as to offer minimum resistance to the flow of
floodwaters;
C. It is anchored to prevent flotation which may result in damage to other structures;
D. All portions of the structure below the FPE must be constructed of flood-resistant
materials;
E. Service utilities such as electrical and heating equipment meet the standards of Section 15.68.310(F)
and Section 15.68.360.,
F. It has openings to allow free flowage of water that meet the criteria in Section 15.68.310(l),
G. The proiect meets all the other requirements of this ordinance, including Section 7 and 15.68.410.
15.68.360 Utilities.
A. All new and replacement water supply systems shall be designed to minimize or eliminate infiltration of
flood waters into the system;
B. New water wells shall be located outside the floodway and shall be protected to the FPE,.
C. New and replacement sanitary sewage systems shall be designed to minimize or eliminate infiltration
of flood waters into the systems and discharges from the systems into the floodwaters;
D. Onsite waste disposal systems shall be located to avoid impairment to them or contamination from
them during flooding.A habitat impact assessment shall be conducted in accordance with Section 15.68.440 as
a condition of approval of an onsite waste disposal system to be located in the Special Flood Hazard Area.
Section 7.Standards for Habitat Protection
The provisions of this Section shall apply in the Special Flood Hazard Area and channel migration zone.
15.68.370 Non-Development Activities.
29
Activities that do not meet the definition of"development"in this chapter are allowed in the regulatory
fleedplainSpecial Flood Hazard Area and Protected Area without the need for a floodplain development permit
under this shapterordinance, provided all other federal, state,Federal, State and local requirements are met.
The following are examples of activities not considered development or manelade"unnatural changes to
improved or unimproved real estate-_
A. 4—Routine maintenance of landscaping that does not involve grading, excavation.or filling;
B. 2 –Removal of noxious weeds and hazard trees and replacement of nennativenon-native vegetation
with native vegetation;
C. 3--Normal maintenance of structures, such as re-roofing and replacing siding,as long =provided
such work does not qualify as a substantial improvement;
D. 4—Normal maintenance of above ground b i -utilities and facilities, such as replacing downed
power lines and utility poles;
E. 6,--Underground and above ground utility work located in previously disturbed areas,with no
significant vegetation impacts, and will have no appreciable change in grade;
€F. Normal maintenance and preservation of public streets and private streets or parking
lots(with approval of Floodplain Administrator) , including, but not limited to filling potholes,patching, crack
seal, chip seal, repaving;and installing signs and traffic sigaalssigns,traffic control devices,
striping/channelization, pavement markings, repair/replacement of sidewalk/curb and gutter,ADA
improvements, non-motorized improvements, repair of guardrails, repair of retaining walls, management of
hazardous trees,fencing repair, lighting repair, but not including expansion of paved areas;
G. 6---Public street improvements with no significant vegetation impacts, and no appreciable change in
grade;
Normal maintenance of a levee or other flood control facility prescribed in the operations and
maintenance plan for the levee or flood control facility are allowed in the Special Flood Hazard Area without the
need for a floodplain development permit. Normal maintenance does not include repair from flood damage,
expansion of the prism, expansion of the face or the toe or addition for protection on the face or toe with rock
armor; and
I. 7-Plowing and other normal farmflood protection practices(other than structures or filling)on farms in
ac
the Special Flood Hazard Area and in existence as of the effective date of thethis ordinance eo •f a ,r�ti,T
chapter-do not require a floodplain development permit. Clearing additional land for agriculture after the date of
this ordinance will require a floodplain development permit and a Habitat Assessment.
D-15.68.380 Activities Allowed with a Floodplain Development Permit.
The following activities are allowed in the regulate4:y- leedplainSpecial Flood Hazard Area without the analysis
required in ACC 15.68.160(C)Section 15.68.410 or the habitat impact assessment required under ACC
15.68.135Q, providing Section 15.68.440, provided that all other requirements of this 6hapterordinance are
met, including obtaining a floodplain development permit:
30
A. 1--Repairs or remodeling of an existing structure;,provided;that the repairs or remodeling are not a
substantial improvement or a repair of substantial damage; - _ -• •• •- •--' -••
B. 2—Expansion or reconstruction of an existing structure that is no greater than-a-0ten percent beyond
its existing footprint;,provided;that the repairs or remodeling are not a substantial improvement or a-repair of
substantial damage. - •• --- -••-• --- - -- - - . -•• •- •• - - e- - - •' - -
If the structure is in the floodway,there shall be no change in the structure's
dimensions perpendicular to flow and a no rise analysis and certification must be provided, even if he change in
dimensions is parallel to flow.
C. 3—Activities with the sole purpose of creating, restoring or enhancing natural functions associated
with floodplains, streams, lakes, estuaries, marine areas, habitat;and riparian areas that meet federalFederal
and ctatcState standards, provided the activities do not include structures, grading,fill, or i ieushard
surfaces.
D. 4—Development of open space and recreational facilities;such as parks,trails;and hunting grounds,
that do not include structures,grading,fill,+mpervioushard surfaces or removal of more than five percent of the
native vegetation on that portion of the property in the Special Flood Hazard Area.
E. &—Repairs to onsite Septic Systems provided the ground disturbance is the minimum necessary and
best management practices (BMP's)to prevent stormwater runoff and soil erosion are used.
15.68.390 Other Activities.
All other activities not-listed in subsesfleaCSections 15.68.370 or 15.68.380 that are
allowed, as long ac by Title 18 (Zoning)of the Auburn City Code are allowed, provided they meet all the other
requirements of this shamsordinance, including the analysis required under Section
15.68.420, 15.68.430, and the habitat impact assessment n-required under ACC 15.68.135(K)
amend-(L-;Section 15.68.440,and a floodplain development permit is issued.
15.68.400 Native Vegetation.
The site plan required in the Floodplain Development Application Packet-shall show existing native vegetation.
A. Within the riparian buffer zone, native vegetation shall be left undisturbed, except as provided in
Sections 15.68.370 and 15.68.380(C).
B. Outside the riparian buffer zone, removal of native vegetation shall not exceed 35 percent of the
surface area of the portion of the site in the Special Flood Hazard Area. Native vegetation in the riparian buffer
zone portion of the property can be counted toward this requirement.
C. If the proposed proiect does not meet the criteria of Sections 15.68.400(A)and (B), a habitat impact
assessment shall be conducted pursuant to Section 15.68.440 and, if necessary, a habitat mitigation plan shall
be prepared and implemented pursuant to Section 15.68.450.
15.68.410FIoodwav Standards.
31
A. In addition to the other requirements of this ordinance, a project to develop in the floodway as
delineated pursuant to Sections 15.68.130(C), 15.68.130(D)or 15.68.150(E)shall meet the following criteria:
1. The applicant shall provide a certification by a registered professional engineer licensed in the
State of Washington demonstrating through hydrologic and hydraulic analyses performed in
accordance with standard engineering practices that the proposed development would not result in any
increase in flood levels during the occurrence of the base flood discharge.
2. Construction or reconstruction of residential structures is prohibited within designated
floodways, except for the following. The following exceptions must still meet all other requirements in
the ordinance, including Section 15.68.4104A)0).
a. Repairs, reconstruction, or improvements to a residential structure that do not
increase the ground floor area, providing the cost of which does not exceed 50 percent of the
market value of the structure either, (1) before the repair,or reconstruction is started, or(2) if
the structure has been damaged, and is being restored, before the damage occurred.Any
project for improvement of a structure to correct existing violations of State or local health,
sanitary, or safety code specifications that have been identified by a local code enforcement
official, and which are the minimum necessary to assure safe living conditions, or to an
historic structure, may be excluded from the 50 percent calculation;
b. Repairs, reconstruction, replacement, or improvements to existing farmhouse
structures located in designated floodways and that are located on lands designated as
agricultural lands of long-term commercial significance under RCW 36.70A.170 may be
permitted subject to the following:
The new farmhouse is a replacement for an existing farmhouse on the same
farm site;
ii. There is no potential building site for a replacement farmhouse on the same
farm outside the designated floodway;
iii. Repairs, reconstruction,or improvements to a farmhouse shall not increase
the total square footage of encroachment of the existing farmhouse,
iv. A replacement farmhouse shall not exceed the total square footage of
encroachment of the farmhouse it is replacing,
v. A farmhouse being replaced shall be removed, in its entirety, including
foundation,from the floodway within ninety days after occupancy of a new farmhouse,
vi. For substantial improvements and replacement farmhouses, the elevation of
the lowest floor of the improvement and farmhouse respectively, including basement,
is a minimum of one foot higher than the BFE,
vii. New and replacement water supply systems are designed to eliminate or
minimize infiltration of floodwaters into the system;
32
viii. New and replacement sanitary sewerage systems are designed and located
to eliminate or minimize infiltration of floodwater into the system and discharge from
the system into the floodwaters; and
ix. All other utilities and connections to public utilities are designed, constructed,
and located to eliminate or minimize flood damage.
c. For all substantially damaged residential structures, other than farmhouses, located
in a designated floodway,the Floodplain Administrator may make a written request that the
Department of Ecology assess the risk of harm to life and property posed by the specific
conditions of the floodway. Based on analysis of depth, velocity,flood-related erosion,
channel migration, debris load potential, and flood warning capability,the Department of
Ecology may exercise best professional judgment in recommending to the local permitting
authority repair, replacement, or relocation of a substantially damaged structure consistent
with WAC 173-158-076. The property owner shall be responsible for submitting to the local
government and the Department of Ecology any information necessary to complete the
assessment. Without a favorable recommendation from the department for the repair or
replacement of a substantially damaged residential structure located in the regulatory
floodway, no repair or replacement is allowed per WAC 173-158-070(1).
d. Before the repair, replacement,or reconstruction is started, all requirements of the
NFIP,the state requirements adopted pursuant to 86.16 RCW, and all applicable local
regulations must be satisfied. In addition,the following conditions must be met:
There is no potential safe building location for the replacement residential
structure on the same property outside the regulatory floodway.
ii. A replacement residential structure is a residential structure built as a
substitute for a legally existing residential structure of equivalent use and size.
iii. Repairs, reconstruction, or replacement of a residential structure shall not
increase the total square footage of floodway encroachment.
iv. The elevation of the lowest floor of the substantially damaged or replacement
residential structure is a minimum of one foot higher than the BFE.
v. New and replacement water supply systems are designed to eliminate or
minimize infiltration of floodwater into the system.
vi. New and replacement sanitary sewerage systems are designed and located
to eliminate or minimize infiltration of floodwater into the system and discharge from
the system into the floodwaters.
vii. All other utilities and connections to public utilities are designed, constructed,
and located to eliminate or minimize flood damage.
e. Repairs, reconstruction, or improvements to residential structures identified as
historic structures that do not increase the building's dimensions.
B. In riverine Special Flood Hazard Areas where a floodway has not been delineated pursuant to
Sections 15.68.130(C), 15.68.130(D) or 15.68.150(E), the applicant for a project to develop in the SFHA shall
33
provide a certification by a registered professional engineer in the State of Washington demonstrating through
hydrologic and hydraulic analyses performed in accordance with standard engineering practices that the
proposed development and all other past or future similar developments would not cumulatively result in an
increase of flood levels during the occurrence of the base flood discharge by more than one-half foot.
15.68.420 Standards for Shallow Flooding Areas(AO Zones)
Shallow flooding areas appear on FIRMs as AO zones with depth designations. The base flood depths in these
zones range from 1 to 3 feet above ground where a clearly defined channel does not exist, or where the path of
flooding is unpredictable and where velocity flow may be evident. Such flooding is usually characterized as
sheet flow. In addition to other provisions in this code,the following additional provisions also apply in AO
zones.
A. New construction and substantial improvements of residential structures and manufactured homes
within AO zones shall have the lowest floor(including basement and mechanical equipment)elevated above
the highest adjacent grade to the structure, one foot or more above the depth number specified in feet on the
community's FIRM (at least two feet above the highest adjacent grade to the structure if no depth number is
specified).
B. New construction and substantial improvements of nonresidential structures within AO zones shall
either:
1. Have the lowest floor(including basement)elevated above the highest adjacent grade of the
building site, one foot or more above the depth number specified on the FIRM (at least two feet if no
depth number is specified); or
2. Together with attendant utility and sanitary facilities, be completely flood proofed to or above
that level so that any space below that level is watertight with walls substantially impermeable to the
passage of water and with structural components having the capability of resisting hydrostatic and
hydrodynamic loads and effects of buoyancy. If this method is used, compliance shall be certified by a
registered professional engineer, or architect as in Section 15.68.310(1).
C. Require adequate drainage paths around structures on slopes to guide floodwaters around and away
from proposed structures.
D. Recreational vehicles placed on sites within AO zones on the community's FIRM either:
1. Be on the site for fewer than 180 consecutive days, or
2. Be fully licensed and ready for highway use, on its wheels or jacking system, is attached to the site
only by quick disconnect type utilities and security devices, and has no permanently attached
additions; or
3. Meet the requirements of subsections(1)and (3)above and the anchoring requirements for
manufactured homes(Section 15.68.330(B)).
15.68.430 Compensatory Storage.
34
New development shall not reduce the effective flood storage volume of the Special Flood Hazard Area.A
development proposal shall provide compensatory storage if grading or other activity eliminates any effective
flood storage volume. Compensatory storage shall:
1. .-. -.
.-- e - -
1. The nature, location, dimensions, and Provide equivalent volumes at equivalent elevations of the-property
in-questieni
• -••-- -- --- '_• e - _-,to that being displaced. For this purpose, "equivalent elevation" means
having similar relationship to ordinary high water bodiedmark and e •- - • ••- -.1 --
efto the site;
-. .- - - _ a _ee -- a._. _ _ -best available:- for
-fe
F
. • •- -- - - - •_•
facilities and roads;
materials;
9. Existing native vegetation and proposed revegctation(see ACC 15.68.161(2).
e. -. - - -- . - - • - - , -- - -- -• - - •- - •- :-• :••e • - 10-year, 50-
year and -- . _.- -_ - - _ _ -- _ _
1. The top of bottom floor(including basement, crawispace, or enclosure floor);
2. The top of the next higher floor;
3. The top of the slab of an attached garage;
5. The lowest adjacent(finished)grade next to structure;
35
A. • -- -- - - - - -- . ._. - - - 100-year
water -.- , - •- • - ' , . - - - - - • - - - - •• -: surface
profiles.
B. Be hydraulically connected to the source of flooding.
C. Provide compensatory storage in the same construction season as when the displacement of flood
storage volume occurs and before the flood season begins.
D. The newly created storage area shall be graded and vegetated to allow fish access during flood events
without creating fish stranding sites.
J-15.68.440 Habitat Impact Assessment.
Unless allowed under ACC 15.68.1300 or(D), anSections 15.68.370 and 15.68.380, a permit application to
develop in the regulatory floodplaiRSpecial Flood Hazard Area shall include an assessment of the impact of the
project on federal, state or locally protected species and habitat,water quality and aquatic and riparian habitat.
The assessment shall be:
A. A Biological Evaluation or : :•.-- - • •' • - •- •-
- •-- ••-• _ . •• -.-. --e : - -• .-"Biological Assessment developed per 50 C.F.R.,
Subsection 402.12 to initiate Federal Interagency consultation under Endangered Species Act Section 7.a.2',
or,
A:B. Documentation that the • - - - •- . •• -•' - , -- --- eactivity fits within Section 74_d
of the Endangered Species Act; or,
13,C. 2—Documentation that the activity fits within a Habitat Conservation Plan
approved pursuant to Section 10 of the Endangered Species Act, where any such assessment has been
prepared or is otherwise made available; or
36
ITD. 4—An assessment prepared in accordance with Regional Guidance for Floodplain Habitat
Assessment and Mitigation, FEMA Region X,2-0402013.The assessment shall determine if the project would
adversely affect:
1. a—Species that are Federal, state or local listed as threatened or endangered.
4-2. The primary constituent elements identifiedfor critical habitat when
;delineated, including but not limited to water quality, water quantity,flood
volumes,flood velocities, spawning substrate, and/or floodplain refugia for listed salmonids.
2,3. b—Essential fish-babitatFish Habitat designated by the National Marine Fisheries Service;,
3 4. a—Fish and wildlife habitat conservation areas;.
e. W—�- a
5. tesOther protected areas and elements necessary for species conservation.
15.68.450 Habitat Mitigation Plan.
A. 1. A. If the assessment conducted under Section 15.68.440-concludes
the project is expected to have an adverse effect on water quality and/or aquatic or riparian habitat or habitat
#unstiensfunction,the applicant shall provide a plan to mitigate those impacts, in accordance with Regional
Guidance for Floodplain Habitat Assessment and Mitigation, FEMA Region X,2-0402013.
1. - -- - e - - - - - - -- - -e • . . -- - - - 30-- - --
outside of the protected areal. If the USFWS or NMFS issues an Incidental Take Permit under
Section 10 of the Endangered Species Act or a Biological Opinion under Section 7 of the Endangered
Species Act;then it can be considered to quality as a plan to mitigate those impacts.
2. 2. If the project is located in the Protected Area,the mitigation plan shall stipulate
avoidance measures as are needed to ensure that there is no adverse effect during any phase of the
project. No compensatory mitigation is allowed in the Protected Area.
4-3. 3. If the project is located outside the Protected Area,the mitigation plan shall include
such avoidance, minimization, restoration, or compensation measures
•- .. - . -• . . . •- . -- .so that indirect adverse effects of development are mitigated such
that equivalent or better habitat protection is provided for the following functions:
1 37
a. 2. a. Stormwater: Reduce flood volumes and stormwater runoff from new
development by ensuring that increased volumes of stormwater reach the river at the same
frequency,timing and duration as historical runoff. Low Impact Development(LID) is required
to be incorporated as described in Section 15.68.270(-B).
b. b. Riparian Vegetation: Maintain or replace riparian function by
providing equivalent area, diversity, and function of riparian vegetation as currently exists on
the site. Riparian retention requirements are outlined in ACC 15.68.400.
c. c. Hyporheic Zones:–No activity is allowed that interferes with the
natural exchange of flow between surface water, groundwater and hyporheic zone,however,
natural hyporheic exchange may be enhanced or restored.
d. d. Wetlands:Wetland function must be maintained or replaced by
providing equivalent function.
e. e. Large Woody Debris: Any large woody debris(LWD) removed from
the floodplain must be replaced in kind, replicating or improving the quantity, size, and species
of the existing LWD per Washington Department of Fish and Wildlife Aquatic Habitat
Guidelines.
4. 4. No new stream crossings are allowed outside the Protected Area unless approval
has been obtained as stated in Section 15.68.460-(A).
B. B. The plan's habitat mitigation activities shall be incorporated into the proposed project.The
floodplain development permit shall be based on the redesigned project and its mitigation components.
C. L. C. As required in Section 15.68.230,the floodplain administrator or designee shall not issue a
certificate of occupancy or final permits until all work identified in the Habitat Assessment and mitigation plan
has been completed or the applicant has provided the necessary assurance that unfinished portions of the
project will be completed, in accordance with Section 15.68.230(-A).
C p, 0--Third—Party Review. For the habitat impact assessment required in sSubsection.415.68.440
ef-this-section-or the habitat mitigation plan required in st+bsestien-#-of-this section,the city may require third-
party review when the professional opinions of the applicant's representative and the city's reviewers cannot be
reconciled. Third-party review requires the applicant's habitat impact assessment, habitat mitigation plan,
and/or additional technical studies to be reviewed by an independent third party, paid for by the applicant but
hired by the city. Third-party review shall be conducted by a qualified consultant as defined in the Floodplain
Habitat Assessment and Mitigation Regional Guidance, FEMA Region X,2010.2013.
15.68.136 Floodplain 460 Alteration of Watercourses and SFHA Boundaries.
A. A. In addition to the other requirements in SestienChapter 15.68, if a project will alter or relocate
boundaries of the SFHA,then the applicant shall also submit a request for a Conditional Letter of Map Revision
(CLOMR),where required by FEMA with engineering documentation and analysis regarding the proposed
change.The project will not be approved unless FEMA issues the CLOMR(which requires Endangered
Species Act consultation) and the provisions of the letter are made part of the permit requirements. If the
change to the BFE or boundaries of the SFHA would normally require a Letter of Map Change,then the project
38
proponent shall initiate, and receive approval of, a Conditional Letter of Map Revision (CLOMR) prior to
approval of the development permit-expiration. The project shall be constructed in a manner consistent with the
approved CLOMR.
C. 15.68.140 Designation of the floodplain administrator.
__._ • -. . - -•e _ . _ • . _ -. - . . - -.If a CLOMR application is made,
then the project proponent shall also supply the full CLOMR documentation package to the Floodplain
Administrator to be attached to the floodplain development permit -:: .-- •- •• ---- -- -: • -
E. 15.68.141 Duties of the floodplain administrator.
i4B. '= •_. .. - .. .. .. _ _ _ ..
including •._- ._. , _ _ - . ::- - .- ••• . •- ••_ e" all required
_ _ -. _ - - - _ . - property owner notifications.
I. C. Review all. The floodplain :- - ::••-• •- ••. - -- - ••'•- . •- ••e- - - -- •-'
chapter are met.
a
administrator or designee shall notify • . - e—- - e_ - - •-
39
P. J. Make interpretations,where needed, as to the exact location of the boundaries of the regulatory
O. 15.68.150 Duties and responsibilities of the public works department.
R. Duties of the public works department regarding flood hazard ar as shall include, but not be limited to:
S. A. Permit Roviow.
T. 1. Review all development permits to determine that the permit requirements of this chapter have
been--satisfied;
V. 3. Review all development permits to determine if the proposed development is located in the
W. B. Uso of Othor Baso Flood Data. When base flood elevation data has not been provided in
chapter.
X. C. Information to Bo Obtainod and Maintainod.
Z. 2. For all new or substantially improved floodproofed structures:
AA. a. Verify and record the actual elevation (in relation to mean sea level);and
BB. b. Maintain the floodproofing certifications required in this chapter.
CD. D. Altoration of Watorcoursos.
EEC. 1. Notify adjacent communities and the Washington Department of Ecology prior to any alteration or
relocation of a watercourse, and submit evidence of such notification to the Federal Insurance Administratiora;
€€D. 2. Require that maintenance isD.Assure that the flood-carryinq capacity of the altered or relocated
portion of the watercourse is maintained. : : _-
•- ':-e __ . ' •• e. If the maintenance program does not call for cutting of native
vegetation, the system shall be oversized at the time of construction to compensate for said vegetation growth
or any other natural factor that may need future maintenance.
40
- . --- • - - -- . . . . - _ e .. - s_ . , . It; a _.
A. Permit Review.
and
41
15.68.160 Standards of the public works department.
A. Utilities.
• .- -- - - - •- --- - - -- - -- - -- - • ':_. , �:..
systems,
that leaves the site or that the adverse effect is mitigated as required in ACC 15.68.1350 and LI.
42
- e.•: ': - --- - ! - .
WAC 173 158 075;
15.68.161 Standards of the planning and development department.
A. Anchoring.
43
native-vegetation.
15.68.170 Additional standards of the planning and development department.
. .. . .. _ .- - • . . - .-
basement.
44
Designs for meeting this requirement must either be certified by a registered professional engineer or
•
.. ..
flooding-.
1.
i. b. The bottom of all openings shall be no higher than one foot above grade.
- - - •- _ - ..
45
foundation-systei
1. It is used only for parking or storage;
fleedwaters
area-
46
H. Critical Facilities.
guidelines.
conditions of this section.
Section 72.3 of 11 CFR Chapter I Federal Emergency Management Agency or a request for
exemption from fccs as specified by Section 72.5 of 44 CFR Chapter 1 Federal Emergency
Management Agency. Sections 72.3 and 72.5 of 44 CFR Chapter I Federal Emergency Management
proposed-actions;
65.6 of 11 CFR Chapter I Federal Emergency Management Agency. Section 65.6 of 44 CFR Chapter
47
B. City Roview of Changos to Flood Hazard Data.
. .
- - . . •- -
existence on the date this provision becomes effective that meets the rest of this chapter's criteria, it may
15.68.190 Developments within areas of special flood hazard.
48
15.68.200 Compensatory storage requirements.
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Ord. 6761 Exhibit B
ACC Chapter 15.68
1
Chapter 15.68
FLOODPLAIN DEVELOPMENT MANAGEMENT
Sections:
Section 1. General
15.68.010 Statutory Authorization.
15.68.020 Purpose.
15.68.030 Lands to which this Ordinance Applies.
15.68.040 Approach.
15.68.050 Penalties for Non-Compliance.
15.68.060 Interpretation.
15.68.070 Abrogation and Greater Restrictions.
15.68.080 Warning and Disclaimer of Liability.
15.68.090 Severability.
Section 2. Definitions
15.68.100 Definitions.
Section 3. Regulatory Data
15.68.110 Area to be Regulated.
15.68.120 Special Flood Hazard Area.
15.68.130 Flood Hazard Data.
15.68.140 Protected Area.
15.68.150 New Regulatory Data.
Section 4.Administration
15.68.160 Establishment of Floodplain Development Permit.
15.68.170 Floodplain Development Permit Application.
15.68.180 Floodplain Development Permit Expiration.
15.68.190 Designation of the Floodplain Administrator.
15.68.200 Duties of the Floodplain Administrator.
15.68.210 Notification to Other Entities.
15.68.220 Records.
15.68.230 Certificate of Occupancy.
15.68.240 Appeals.
15.68.250 Variance Criteria.
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Section 5.General Development Standards
15.68.260 Subdivisions.
15.68.270 Site Design.
15.68.280 Hazardous Materials.
15.68.290 Critical Facilities.
Section 6.Standards for Protection of Structures
15.68.300 Applicability.
15.68.310 Flood Protection Standards.
15.68.320 Nonresidential Construction.
15.68.330 Manufactured Homes.
15.68.340 Recreation Vehicles.
15.68.350 Appurtenant Structures.
15.68.360 Utilities.
Section 7.Standards for Habitat Protection
15.68.370 Non-Development Activities.
15.68.380 Activities Allowed with a Floodplain Development Permit.
15.68.390 Other Activities.
15.68.400 Native Vegetation.
15.68.410 Floodway Standards.
15.68.420 Standards for Shallow Flooding Areas (AO Zones)
15.68.430 Compensatory Storage.
15.68.440 Habitat Impact Assessment.
15.68.450 Habitat Mitigation Plan.
15.68.460 Alteration of Watercourses and SFHA Boundaries.
Section 1. General
15.68.010 Statutory Authorization.
A. The Legislature of the State of Washington has delegated the responsibility to local governmental units
to adopt regulations designed to promote the public health, safety and general welfare of its citizenry.
Therefore,the City does ordain as follows:
B. Findings of Fact:
Areas of Auburn are subject to periodic inundation and channel migration which may result in loss of life and
property, health and safety hazards, disruption of commerce and governmental services, extraordinary public
expenditures for protection and relief from flooding and channel migration, and impairment of the tax base, all
of which adversely affect the public health, safety and general welfare.
3
When floodplains and watersheds are developed without taking appropriate care and precautions,flood
heights,frequencies, and velocities increase, which may cause a greater threat to humans, damage to
property, destruction of natural floodplain functions, and adverse impacts to water quality and habitat.
Rivers, streams, lakes, estuarine and marine areas and their floodplains are major elements of healthy aquatic
and riparian areas and conveyance of flood waters. If watersheds, rivers, streams, lakes, estuaries,floodplains
and other systems are not viewed holistically as biological and geomorphologic units, it may lead to serious
degradation of habitat and increased flood hazards to people and human development.
Over the years, natural processes have evolved that manage flood waters and channel flows in the most
effective and efficient manner. Disruption of these processes through alterations to land cover, stream
channels,wetlands and other water bodies which may lead to increased flood hazards, loss of life and
property,threats to public health, and loss of habitat.
15.68.020 Purpose.
It is the purpose of this ordinance to promote the public health, safety, and general welfare and to minimize
public and private losses due to flood conditions in specific areas by provisions designed to manage
development in order to:
A. Protect human life, health and property from the dangers of flooding;
B. Minimize the need for publicly funded and hazardous rescue efforts to save those who are isolated by
floodwaters;
C. Minimize expenditure of public money for costly flood damage repair and flood control projects;
D. Minimize disruption of commerce, governmental services, and government infrastructure;
E. Minimize damage to public facilities and utilities such as water and gas mains, electric, telephone and
sewer lines, streets and bridges located in the floodplain.;
F. Minimize cost impacts to public facilities and utilities such as water and gas mains, electric, telephone
and sewer lines, streets and bridges located in the special flood hazard area.;
G. Maintain a stable tax base by providing for the sound use of and development of flood hazard areas so
as to minimize blight areas caused by flooding;
H. Encourage those who occupy flood hazard areas be educated about the risks and challenges
associated with these areas.;
I. Qualify the City of Auburn for participation in the National Flood Insurance Program,thereby giving
citizens and businesses the opportunity to purchase flood insurance;
J. Maintain the quality of water in rivers, streams, and lakes, and their floodplains so as to protect public
water supplies, areas of the Public Trust, and wildlife habitat protected by the Endangered Species Act;
K. Retain the natural channel, shoreline, and floodplain creation processes and other natural floodplain
functions that protect, create, and maintain habitat for threatened and endangered species; and
L. Prevent or minimize loss of hydraulic, geomorphic, and ecological functions of floodplains and stream
channels.
15.68.030 Lands to which this Ordinance Applies.
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This ordinance shall apply to the Special Flood Hazard Area (SFHA)and associated protected areas within the
jurisdiction of the City of Auburn as defined in Section 3 of this Ordinance.
15.68.040 Approach.
In order to achieve the listed purposes,this ordinance:
A. Defines and clarifies the terms and phrases used in this ordinance in Section 2.
B. Identifies in Section 3 the Special Flood Hazard Area, the Protected Area and the supporting technical
data needed to delineate those areas.
C. Establishes a permit requirement in Section 4 so that all proposed development that may affect flood
hazards,water quality and habitat is reviewed prior to construction.
D. Sets minimum protection standards in Section 5 for all development to ensure that the development
will not increase the potential for flood damage or adversely affect natural floodplain functions.
E. Sets minimum protection standards to protect new and substantially improved structures from flood
damage in Section 6.
F. Specifies additional habitat protection criteria in Section 7. Some small projects do not need a
floodplain development permit(see ACC 15.68.380). For all other development projects,the applicant must
assess their impact on those factors that contribute to increased flood hazard and degradation of habitat. If the
assessment concludes that the project will cause an adverse effect outside the Protected Area, the permit will
be denied, unless the project impacts are mitigated (avoided, minimized, restored or compensated for).
15.68.050 Penalties for Noncompliance.
No development shall be undertaken or placed in the areas regulated by this ordinance without full compliance
with the terms of this ordinance and other applicable regulations of the City.Violation of the provisions of this
chapter by failure to comply with any of its requirements(including violations of conditions and safeguards
established in connection with conditions) shall be enforced pursuant to the provisions of Chapter 1.25 ACC.
15.68.060 Interpretation.
In the interpretation and application of this ordinance, all provisions shall be:
A. Considered as minimum requirements;
B. Liberally construed in favor of the City; and,
C. Deemed neither to limit nor repeal any other powers granted under state statutes;
15.68.070 Abrogation and Regulation Conflicts
Where this ordinance and another code, or ordinance, conflict or overlap, whichever imposes the more
stringent restrictions shall prevail.
15.68.080 Warning and Disclaimer of Liability.
The degree of property and habitat protection required by this ordinance is considered reasonable for
regulatory purposes and is based on scientific and engineering considerations. Larger floods and movement of
channels outside of mapped channel migration areas may occur on rare occasions. Flood heights may be
increased by unnatural or natural causes. This ordinance does not imply that land outside the regulated areas
5
or development permitted within such areas will be free from flood or erosion damage. This ordinance shall not
create liability on the part of the City, any officer or employee thereof, for any damage to property or habitat that
results from reliance on this ordinance or any administrative decision lawfully made hereunder.
15.68.090 Severability
The provisions and sections of this ordinance shall be deemed separable and the invalidity of any portion of
this ordinance shall not affect the validity of the remainder.
Section 2. Definitions
15.68.100 Definitions.
Unless specifically defined below, terms or phrases used in this ordinance shall be interpreted so as to give
them the meaning they have in common usage and to give this ordinance its most reasonable application.
A. "Adversely affect/adverse effect"means effects that are a direct or indirect result of the proposed
action or its interrelated or interdependent actions and the effect is not discountable, insignificant, or beneficial.
Discountable effects are extremely unlikely to occur. Insignificant effects relate to the size of the impact and
should never reach the scale where a take occurs. Based on best judgment, a person would not: 1) be able to
meaningfully measure, detect, or evaluate insignificant effects, or 2) expect discountable effects to occur.
Beneficial effects are contemporaneous positive effects without any adverse effects. In the event that the
overall effect of the proposed action is beneficial, but is also likely to cause some adverse effects, then the
proposed action is considered to result in an adverse effect.
B. "Alteration of watercourse" means any action that will change the location of the channel occupied by
water within the banks of any portion of a riverine waterbody.
C. "Appurtenant Structure" means a structure which is on the same parcel as the principle structure to be
insured and the use of which is incidental to the use of the principal structure.
D. "Area of shallow flooding" means a designated zone AO, AH,AR/AO or AR/AH (or VO)on a
community's Flood Insurance Rate Map (FIRM)with a one percent or greater annual chance of flooding to an
average depth of one to three feet where a clearly defined channel does not exist, where the path of flooding is
unpredictable, and where velocity flow may be evident. Such flooding is characterized by ponding or sheet flow.
Also referred to as the sheet flow area.
E. "Area of special flood hazard" means the land in the floodplain within a community subject to a 1
percent or greater chance of flooding in any given year. It is shown on the Flood Insurance Rate Map (FIRM)
as zone A,AO, AH, A1-30, AE,A99,AR(V,VO,V1-30, VE). "Special flood hazard area" is synonymous in
meaning with the phrase"area of special flood hazard".
F. "ASCE 24" means the most recently published version of ASCE 24, Flood Resistant Design and
Construction, published by the American Society of Civil Engineers.
G. "Base flood" means the flood having a one percent chance of being equaled or exceeded in any given
year(also referred to as the"100-year flood").
H. "Base flood elevation" means the elevation to which floodwater is anticipated to rise during the base
flood.
6
"Basement" means any area of the structure having its floor subgrade (below ground level)on all
sides.
J. "Building Code"means the currently effective versions of the International Building Code and the
International Residential Code adopted by the Washington State Legislature and any further amendments
adopted by the City of Auburn.
K. "Channel Migration Zone" (CMZ) means the area within the lateral extent of likely stream channel
movement due to stream bank destabilization and erosion, rapid stream incision, aggradation, avulsions, and
shifts in location of stream channels.
1. The channel migration area shall be the total area occupied by the river channel, the severe
channel migration hazard area, and the moderate channel migration hazard area as delineated in the
Green River Channel Migration Study published by King County dated December 1993 plus 50 feet.
2. The channel migration area shall be the total area occupied by the river channel,the severe
channel migration hazard area, and the moderate channel migration hazard area as delineated in the
Channel Migration Zone Delineation for the Middle Green River, RM 31.10 to 33.25 dated December
28, 2018 plus 50-feet which supersedes the study referenced above.
3. A site specific channel migration delineation may also be performed per the Washington State
Department of Ecology's current requirements with recommended setbacks (A Framework for
Delineating Channel Migration Zones) prepared by a qualified engineer. The delineation shall be
prepared by a qualified consultant as that term is defined in these regulations.The city may retain a
qualified consultant paid for by the applicant to review and confirm the applicant's reports, studies and
plans if the following circumstances exist:
a. The city has technical information that is unavailable to the applicant; or
b. The applicant has provided inaccurate or incomplete information on previous
proposals or proposals currently under consideration.
L. "Critical facility" means a facility necessary to protect the public health, safety and welfare during a
flood. Critical facilities include, but are not limited to, schools, nursing homes, hospitals, police,fire and
emergency operations installations,water and wastewater treatment plants, electric power stations, and
installations which produce, use, or store hazardous materials or hazardous waste(other than consumer
products containing hazardous substances or hazardous waste intended for household use).
M. "Development" means any human-made change to improved or unimproved real estate including but
not limited to buildings or other structures, mining, dredging,filling, grading, paving, excavation or drilling
operations or storage of equipment or materials located within the area of special flood hazard.
N. "Dry floodproofing"means any combination of structural and nonstructural measures that prevent flood
waters from entering a structure.
O. "Elevation Certificate"means an administrative tool of the National Flood Insurance Program (NFIP)
that can be used to provide elevation information, to determine the proper insurance premium rate, and to
support a request for a Letter of Map Amendment(LOMA) or Letter of Map Revision based on fill (LOMR-F).
P. "Essential Facility" has the same meaning as"Essential Facility"defined in ASCE 24. Table 1-1 in
ASCE 24-14 further identifies building occupancies that are essential facilities.
7
Q. "FEMA" means the Federal Emergency Management Agency,the agency responsible for
administering the National Flood Insurance Program.
R. "Flood"or"flooding" means a general and temporary condition of partial or complete inundation of
normally dry land areas from:
1. The overflow of inland or tidal waters; and/or
2. The unusual and rapid accumulation of runoff of surface waters from any source.
3. Mudslides(i.e., mudflows)which are proximately caused by flooding as defined in paragraph
(2) of this definition and are akin to a river of liquid and flowing mud on the surfaces of normally dry
land areas, as when earth is carried by a current of water and deposited along the path of the current.
4. The collapse or subsidence of land along the shore of a lake or other body of water as a result
of erosion or undermining caused by waves or currents of water exceeding anticipated cyclical levels
or suddenly caused by an unusually high water level in a natural body of water, accompanied by a
severe storm, or by an unanticipated force of nature, such as flash flood or an abnormal tidal surge, or
by some similarly unusual and unforeseeable event which results in flooding as defined in paragraph
(1) of this definition.
S. "Flood elevation study" means an examination, evaluation and determination of flood hazards and, if
appropriate, corresponding water surface elevations, or an examination, evaluation and determination of
mudslide (i.e., mudflow) and/or flood-related erosion hazards. Also known as a Flood Insurance Study(FIS).
T. "Flood insurance rate map (FIRM)" means the official map on which the Federal Insurance
Administrator has delineated both the Special Flood Hazard Areas and the risk premium zones applicable to
the community.
U. "Flood insurance study(FIS)" See"Flood Elevation Study"
V. "Floodplain or flood prone area" means any land area susceptible to being inundated by water from
any source. See"Flood or flooding."
W. "Floodplain administrator" means the community official designated by title to administer and enforce
the floodplain management regulations.
X. "Flood proofing" means any combination of structural and nonstructural additions, changes, or
adjustments to structures which reduce or eliminate risk of flood damage to real estate or improved real
property,water and sanitary facilities, structures, and their contents. Flood proofed structures are those that
have the structural integrity and design to be impervious to floodwater below the Base Flood Elevation.
Y. "Flood protection elevation (FPE)" means the elevation above the datum of the effective FIRM to which
new and substantially improved structures must be protected from flood damage.
Z. "Floodway" means the channel of a river or other watercourse and the adjacent land areas that must
be reserved in order to discharge the base flood without cumulatively increasing the water surface elevation
more than a designated height.Also referred to the"Regulatory Floodway.
AA. "Functionally Dependent Use" means a use which cannot perform its intended purpose unless it is
located or carried out in close proximity to water. The term includes only docking facilities, port facilities that are
necessary for the loading and unloading of cargo or passengers, and ship building and ship repair facilities, and
does not include long-term storage or related manufacturing facilities.
8
BB. "Highest adjacent grade" means the highest natural elevation of the ground surface prior to
construction next to the proposed walls of a structure.
CC. "Historic structure" means any structure that is:
1. Listed individually in the National Register of Historic Places (a listing maintained by the
Department of Interior)or preliminarily determined by the Secretary of the Interior as meeting the
requirements for individual listing on the National Register;
2. Certified or preliminarily determined by the Secretary of the Interior as contributing to the
historical significance of a registered historic district or a district preliminarily determined by the
Secretary to qualify as a registered historic district;
3. Individually listed on a state inventory of historic places in states with historic preservation
programs which have been approved by the Secretary of Interior; or
4. Individually listed on a local inventory of historic places in communities with historic
preservation programs that have been certified either:
a. By an approved state program as determined by the Secretary of the Interior, or
b. Directly by the Secretary of the Interior in states without approved programs.
DD. "Hyporheic zone" means a saturated layer of rock or sediment beneath and/or adjacent to a stream
channel that contains some proportion of channel water or that has been altered by channel water infiltration.
EE. "Impervious surface"means a non-vegetated surface area which 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 which similarly impede the
natural infiltration of stormwater.
FF. "Lowest floor"means the lowest floor of the lowest enclosed area (including basement An unfinished
or flood-resistant enclosure, usable solely for parking of vehicles, building access, or storage in an area other
than a basement area is not considered a building's lowest floor provided that such enclosure is not built so as
to render the structure in violation of the applicable non-elevation design requirements of this chapter found in
ACC 15.68.170(A)(7) (i.e. provided there are adequate flood ventilation openings).
GG. "Manufactured home" means a structure,transportable in one or more sections,which is built on a
permanent chassis and is designed for use with or without a permanent foundation when attached to the
required utilities. The term "manufactured home"does not include a"recreational vehicle."
HH. "Manufactured home park or subdivision"means a parcel (or contiguous parcels) of land divided into
two or more manufactured home lots for rent or sale.
II. "Market value" shall mean the current assessed value as established by the most recent tax roll of the
county assessor in which the property is located. An applicant may, at applicant's expense, provide an
appraisal to determine market value.
JJ. "Mean Sea Level" means for purposes of the National Flood Insurance Program, the vertical datum to
which Base Flood Elevations shown on a community's Flood Insurance Rate Map are referenced.
9
KK. "Native vegetation" means plant species that are indigenous to the community's area and that
reasonably could be expected to naturally occur on the site.
LL. "Natural floodplain functions" means the contribution that a floodplain makes to support habitat,
including, but not limited to, providing flood storage and conveyance, reducing flood velocities, reducing
sedimentation, filtering nutrients and impurities from runoff, processing organic wastes, moderating
temperature fluctuations, and providing breeding and feeding grounds, shelter, and refugia,for aquatic or
riparian species.
MM. "New construction" means for the purposes of determining insurance rates, structures for which the
"start of construction"commenced on or after the effective date of an initial Flood Insurance Rate Map or after
December 31, 1974, whichever is later, and includes any subsequent improvements to such structures. For
floodplain management purposes, "new construction"means structures for which the"start of construction"
commenced on or after the effective date of the ordinance adopted by a community and includes any
subsequent improvements to such structures.
NN. "Principal Structure" means a structure in which the principal use of the lot on which it is located is
conducted.
00. "Protected area" means the lands that lie within the boundaries of the floodway,the riparian buffer
zone, and the channel migration area. Because of the impact that development can have on flood heights and
velocities and habitat, special rules apply in the Protected Area.
PP. "Reasonably Safe from Flooding" means development that is designed and built to be safe from
flooding based on consideration of current flood elevation studies, historical data, high water marks and other
reliable data known to the community. In unnumbered A zones where flood elevation information is not
available and cannot be obtained by practicable means, reasonably safe from flooding means that the lowest
floor is at least two feet above the Highest Adjacent Grade.
QQ. "Recreational vehicle" means a vehicle:
1. Built on a single chassis; and,
2. Four hundred square feet or less when measured at the largest horizontal projection; and,
3. Designed to be self-propelled or permanently towable by an automobile or light-duty truck;
and,
4. Designed primarily not for use as a permanent dwelling but as temporary living quarters for
recreational, camping, travel or seasonal use.
RR. "Riparian" means of, adjacent to, or living on, the bank of a stream, lake, pond, sound, or other water
body.
SS. "Riparian buffer zone" means the land located adjacent to streams, and other bodies of water, where
the natural soil, hydrology, and native flora and fauna perform important ecological functions such as protecting
the water body by filtering out pollutants, preventing erosion and sedimentation, stabilizing stream banks, and
providing natural shade. They are often thin lines-of-green containing native grasses, flowers, shrubs and trees
that line the banks of streams and other bodies of water.The riparian buffer zone for the Puget Sound
Biological Opinion applies only to areas mapped within the Special Flood Hazard Area, unless the area is
10
undeveloped with predominately native vegetation that have benefits to endangered species, in which case the
regulations for riparian habitat zones shall apply.
TT. "Riparian Habitat Zone" means the water body and adjacent land areas that are likely to support
aquatic and riparian habitat.
UU. "Special flood hazard area(SFHA)" means the land subject to inundation by the base flood. Special
flood hazard areas are designated on Flood Insurance Rate Maps with the letters"A"or"V" include AE
(floodway),AO,AH,A1-99 and VE. The Special Flood Hazard Area is also referred to as the area of special
flood hazard or SFHA.
VV. "Start of construction" includes substantial improvement, and means the date the building permit was
issued, provided the actual start of construction, repair, reconstruction, rehabilitation, addition, placement or
other improvement was within 180 days of the date of the permit. The actual start means either the first
placement of permanent construction of a structure on a site, such as the pouring of slab or footings,the
installation of piles,the construction of columns, or any work beyond the stage of excavation; or the placement
of a manufactured home on a foundation. Permanent construction does not include land preparation, such as
clearing, grading and filling; nor does it include the installation of streets and/or walkways; nor does it include
excavation for a basement,footings, piers, or foundations or the erection of temporary forms; nor does it
include the installation on the property of accessory buildings, such as garages or sheds not occupied as
dwelling units or not part of the main structure. For a substantial improvement, the actual"start of construction"
means the first alteration of any wall, ceiling,floor, or other structural part of a building,whether or not that
alteration affects the external dimensions of the building.
WW. "Structure" means a walled and roofed building, including a gas or liquid storage tank, that is principally
above ground, as well as a manufactured home.
XX. "Substantial damage" means damage of any origin sustained by a structure whereby the cost of
restoring the structure to its before-damaged condition would equal or exceed 50 percent of the market value of
the structure before the damage occurred
YY. "Substantial improvement" means any reconstruction, rehabilitation, addition, replacement or
improvement of a structure,the cost of which equals or exceeds 50 percent of the market value of the structure
before the"start of construction"of the improvement. This term includes structures which have incurred
"substantial damage,"regardless of the actual repair work performed.
The term does not, however, include either:
1. Any project for improvement of a structure to correct existing violations of state or local health,
sanitary, or safety code specifications that have been identified by the local code enforcement official
and that are the minimum necessary to assure safe living conditions; or
2. Any alteration of a"historic structure" provided that the alteration will not preclude the
structure's continued designation as a"historic structure".
ZZ. "Variance"means a grant of relief from the requirements of this ordinance which permits construction
in a manner that would otherwise be prohibited by this ordinance.
AAA. "Violation"means the failure of a structure or other development to be constructed or implemented in
conformance with the community's applicable floodplain development regulations.
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BBB. "Water typing" means a system for classifying water bodies according to their size and fish habitat
characteristics. The Washington Department of Natural Resources Forest Practices Water Typing
Classification System is hereby adopted by reference.The system defines four water types:
1. Type"S"—Shoreline: Streams that are designated"shorelines of the state,"including marine
shorelines.
2. Type"F"—Fish: Streams that are known to be used by fish or meet the physical criteria to be
potentially used by fish.
3. Type"Np"—Non-fish perennial streams.
4. Type"Ns"—Non-fish seasonal streams.
CCC. "Zone" means one or more areas delineated on the FIRM. The following zones may be used on the
adopted FIRM. The special flood hazard area is comprised of the A and V Zones.
1. A: SFHA where no base flood elevation is provided.
2. AE: SFHA with a base flood elevation.
3. AO: SFHA subject to inundation by shallow flooding usually resulting from sheet flow on
sloping terrain, with average depths between one and three feet. Average flood depths are shown.
4. AH: SFHA subject to inundation by shallow flooding (usually areas of ponding)with average
depths between one and three feet. Base flood elevations are shown.
5. D:Area of undetermined but possible flood hazard.
6. X: The area outside the mapped SFHA with a low risk of flooding.
7. Shaded X:An area of moderate risk of flooding from the base flood, and defined as:
a. areas of shallow(i.e., less than 1 foot)flooding;
b. 0.2%chance (or 500-year)flooding;
c. has a drainage area less than 1 sq. mile; or
d. areas protected by a levee.
Section 3. Regulatory Data
15.68.110 Area to be Regulated.
The area to be regulated is comprised of the Special Flood Hazard Area and all Protected Areas within the
Special Flood Hazard Area within the jurisdiction of the City of Auburn. The term also includes areas delineated
pursuant to Section 15.68.150.
15.68.120 Special Flood Hazard Area.
Basis for Establishing the Areas of Special Flood Hazard
A. The special flood hazard areas identified by the Federal Insurance Administrator in a scientific and
engineering report entitled"The Flood Insurance Study (FIS)for King County Washington and Incorporated
Areas"dated August 19, 2020,and any revisions thereto,with accompanying Flood Insurance Rate Maps
(FIRMS)dated August 19, 2020, and any revisions thereto,as well as the special flood hazard areas identified
by the Federal Insurance Administrator in a scientific and engineering report entitled"The Flood Insurance
Study(FIS)for Pierce County Washington and Incorporated Areas"dated March 7, 2017, and any revisions
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thereto,with accompanying Flood Insurance Rate Maps(FIRMs)dated March 7,2017, and any revisions
thereto, are hereby adopted by reference and declared to be a part of this ordinance.The FIS and the FIRM
are on file at 1 East Main St,Auburn,WA 98001.
B. The best available information for flood hazard area identification as outlined in Section 15.68.130(D)
shall be the basis for regulation until a new FIRM is issued that incorporates data utilized under Section
15.68.130(D).
C. Upon receipt of a floodplain development permit application,the floodplain administrator or designee
shall compare the elevation of the site to the base flood elevation.
D. The floodplain administrator or designee shall inform the applicant that the project may still be subject
to the flood insurance purchase requirements unless the owner receives a Letter of Map Amendment(LOMA)
from FEMA.
E. The floodplain administrator or designee shall make interpretations where needed, as to the exact
locations of the boundaries of the SFHA and the Protected Area (e.g.where there appears to be a conflict
between the mapped SFHA boundary and actual field conditions as determined by the base flood elevation and
ground elevations) as it applies to proposed development. The applicant may appeal the floodplain
administrator's or designee's interpretation of the location of the boundary to the Hearing Examiner for the City
of Auburn.
15.68.130 Flood Hazard Data.
A. The base flood elevation for the SFHAs incorporated in 15.68.120(A)shall be utilized.
B. The Flood Protection Elevation (FPE) shall be the base flood elevation plus one (1)foot.
C. The floodway shall be as delineated on the Flood Insurance Rate Map.
D. Where base flood elevation and floodway data have not been provided in Special Flood Hazard Areas,
the floodplain administrator or designee shall obtain, review and reasonably utilize any base flood elevation and
floodway data available from a Federal, State or other source.
15.68.140 Protected Area.
A. The Protected Area is comprised of those lands that lie within the boundaries of the floodway, the
riparian buffer zone, and the channel migration area.
B. In riverine areas, where a floodway has been designated in accordance with Sections 15.68.130(C),
15.68.130(D) or 15.68.150(E), the Protected Area is comprised of those lands that lie within the boundaries of
the riparian buffer zone, the channel migration area, and the SFHA.
C. Riparian Buffer Zone: The riparian buffer zone includes those watercourses within the SFHA and
adjacent land areas that are likely to support aquatic and riparian habitat.
1. The size and location of the riparian buffer zone is dependent on the type of water body. The
riparian buffer zone includes the water body and adjacent lands, measured perpendicularly from
ordinary high water mark on both sides of the water body:
a. Type S streams that are designated"shorelines of the State:"250 feet
b. Type F streams (fish bearing) streams greater than 5 feet wide and marine
shorelines: 200 feet
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c. Type F streams less than 5 feet wide and lakes: 150 feet
d. Type N (nonsalmonid-bearing) perennial and seasonal streams with unstable slopes:
225 feet
e. All other Type N (nonsalmonid-bearing) perennial and seasonal streams: 150 feet.
2. The riparian buffer zone shall be delineated on the site plan by the applicant at the time of
application for subdivision approval or floodplain development permit for all development proposals
within 300 feet of any stream or shoreline.
D. Channel Migration Area:
a. The channel migration area shall be the channel migration zone as defined in Section
15.68.100(K).
b. Where more than one channel migration zone has been delineated,the floodplain
administrator or designee shall use the delineation that has been adopted for other local
regulatory purposes.
c. Where a channel migration zone has not yet been mapped, the provisions of Section
15.68.150(D)shall apply at the time of permit application.
15.68.150 New Regulatory Data.
A. All requests to revise or change the flood hazard data, including requests for a Letter of Map Revision
and a Conditional Letter of Map Revision shall be reviewed by the floodplain administrator or designee.
1. The floodplain administrator or designee shall not sign the Community Acknowledgment Form
for any requests based on filling or other development, unless the applicant for the letter documents
that such filling or development is in compliance with this ordinance.
2. The floodplain administrator or designee shall not approve a request to revise or change a
floodway delineation until FEMA has issued a Conditional Letter of Map Revision that approves the
change.
B. If an applicant disagrees with the regulatory data prescribed by this ordinance, he/she may submit a
detailed technical study needed to replace existing data with better data in accordance with FEMA mapping
guidelines or Regional Guidance for Hydrologic and Hydraulic Studies in Support of the Model Ordinance for
Floodplain Management under the National Flood Insurance Program and Endangered Species Act FEMA
Region X, 2010. If the data in question are shown on the published FIRM,the submittal must also include a
request to FEMA for a Conditional Letter of Map Revision.
C. Where base flood elevation data are not available in accordance with Section 15.68.130, applicants for
approval of new subdivisions and other proposed developments (including proposals for manufactured home
parks)greater than 50 lots or 5 acres, whichever is the lesser, shall include such data with their permit
applications.
D. Where channel migration zone data are not available in accordance with 15.68.140(D),the permit
applicant shall either:
1. Designate the entire SFHA as the channel migration zone or
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2. Identify the channel migration area in accordance with Regional Guidance for Hydrologic and
Hydraulic Studies in Support of the Model Ordinance for Floodplain Management under the National
Flood Insurance Program and Endangered Species Act FEMA Region X, 2012.
E. All new hydrologic and hydraulic flood studies conducted pursuant to Section 15.68.150 shall be in
accordance with Regional Guidance for Hydrologic and Hydraulic Studies in Support of the Model Ordinance
for Floodplain Management under the National Flood Insurance Program and the Endangered Species Act,
FEMA, Region X, 2010.
F. The floodplain administrator shall use the most restrictive data available prepared specifically for the
project site for the channel migration zone, floodways,future conditions, and riparian buffer zone.
Section 4.Administration
15.68.160 Establishment of Floodplain Development Permit
A floodplain development permit shall be obtained before construction or development begins within the
Special Flood Hazard Area (SFHA)or Protected Area. The permit shall be for all development as set forth in
15.68.170 Floodplain Development Permit Application.
Applications for a floodplain development permit shall be made using the criteria outlined in the Floodplain
Development Application Packet available for download at www.auburnwa.gov/forms. At a minimum,the
following information is required.
A. Proposed elevation in relation to mean sea level, of the lowest floor(including basement) of all
structures recorded on a current elevation certificate with Section B completed by the Floodplain Administrator.
B. Proposed elevation in relation to mean sea level to which any structure will be flood proofed;
C. Where a structure is to be flood proofed, certification by a registered professional engineer or architect
that the flood proofing methods for any nonresidential structure meet flood proofing criteria in Section 5;
D. Description of the extent to which a watercourse will be altered or relocated as a result of proposed
development;
E. Where development is proposed in a floodway, an engineering analysis indicating no rise of the Base
Flood Elevation; and
F. Any other such information that may be reasonably required by the Floodplain Administrator in order to
review the application.
15.68.180 Floodplain Development Permit Expiration.
If there has been no start of construction, a floodplain development permit shall expire 180 days after the date
of issuance.Where the applicant documents a need for an extension beyond this period due to conditions
beyond the applicant's control,the floodplain administrator or designee may authorize one or more extensions.
15.68.190 Designation of the Floodplain Administrator.
The Director of Community Development is hereby appointed to administer, interpret, implement, and enforce
this ordinance by granting or denying floodplain development permit applications in accordance with its
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provision. The Director of Community Development may designate administration of portions or all of this
ordinance to a qualified person.
15.68.200 Duties of the Floodplain Administrator.
Duties of the floodplain administrator or designee shall include, but are not limited to:
A. Review all floodplain development permits to determine that the permit requirements of this ordinance
have been satisfied.
B. Review all floodplain development permits to determine that all necessary permits have been obtained
from those Federal, State or local government agencies from which prior approval is required, including those
local, State or Federal permits that may be required to assure compliance with the Endangered Species Act
and/or other appropriate State or Federal laws.
C. Review all floodplain development permits to determine if the proposed development is located in the
Protected Area. If located in the Protected Area, ensure that the provisions of Section 7 are met.
D. Ensure that all development activities within the Special Flood Hazard Area of the jurisdiction of the
City meet the requirements of the ordinance.
E. Inspect all development projects before, during and after construction to ensure compliance with all
provisions of this ordinance, including proper elevation of the structure.
F. Maintain for public inspection all records pertaining to the provisions of this ordinance.
G. Submit reports to include the projects for which they issue floodplain development permits, including
effects to flood storage,fish habitat, and all indirect effects of development and mitigation provided to FEMA as
required by the National Flood Insurance Program.
H. Notify FEMA of any proposed amendments to this ordinance and when annexations occur in the
Special Flood Hazard Area.
I. Ensure the proposed development is not located in the floodway. If located in the floodway, assure the
encroachment provisions of Section 15.68.410 are met
J. Cooperate with State and Federal agencies to improve flood and other technical data and notify FEMA
of any new data that would revise the FIRM.
K. Review all floodplain development permits to verify that proposed development will be reasonably safe
from flooding.
15.68.210 Notification to Other Entities
Whenever a watercourse is to be altered or relocated:
A. Notify adjacent communities and the Department of Ecology prior to such alteration or relocation of a
watercourse, and submit evidence of such notification to the Federal Insurance Administrator through
appropriate notification means, and
B. Assure that the flood carrying capacity of the altered or relocated portion of said watercourse is
maintained.
15.68.220 Records.
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A. Where base flood elevation data have been obtained pursuant to Section 15.68.130 and 15.68.150,
the floodplain administrator or designee shall obtain, record, and maintain the actual"finished construction"
elevations provided by the applicant for the locations listed in Section 15.68.170. This information shall be
recorded on a current FEMA Elevation Certificate signed and sealed by a professional land surveyor, currently
licensed in the State of Washington.
B. For all new or substantially improved dry floodproofed nonresidential structures,where base flood
elevation data has been obtained pursuant to Section 15.68.130 and 15.68.150,the floodplain administrator or
designee shall obtain, record and maintain the elevation (in relation to the datum of the effective FIRM)to
which the structure was floodproofed. This information shall be recorded on a current FEMA Floodproofing
Certificate by a professional engineer currently licensed in the State of Washington.
C. Certification required by Section 15.68.410(floodway encroachments).
D. Records of all variance actions, including justification for their issuance.
E. Improvement and damage calculations.
F. Maintain for public inspection all records pertaining to the provisions of this ordinance.
15.68.230 Certificate of Occupancy.
A. A final grading and/or storm permit for the property, physical completion for City of Auburn Capital
Improvement projects without a building, a certificate of occupancy(commercial building)or final building
inspection (residential structure)for a new or substantially improved structure or an addition shall not be issued
until:
1. The permit applicant provides a properly completed, signed and sealed Elevation or
Floodproofing Certificate showing finished construction data as required by Section 15.68.220;
2. If a mitigation plan is required by Sections 15.68.440 and 15.68.450, all work identified in the
plan has been completed according to the plan's schedule;
3. The applicant provides copies of all required Federal, State, and local permits noted in the
permit application per Section 15.68.170;
4. All other provisions of this ordinance and conditions placed on the floodplain development
permit approval letter have been met.
15.68.240 Appeals.
A. The Hearing Examiner, as established by Chapter 2.46 of the Auburn City Code, shall hear and decide
appeals and requests for variances from the requirements of this ordinance.
B. The Hearing Examiner shall hear and decide appeals when it is alleged there is an error in any
requirement, decision, or determination made by the floodplain administrator or designee in the enforcement or
administration of this ordinance.
C. Those aggrieved by the decision of the Hearing Examiner may appeal the decision to the superior
court of the county in which the project is located pursuant to Section 2.46.160 of the Auburn City Code.
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D. Upon consideration of the factors of Section 15.68.250 and the purposes of this ordinance,the
Hearing Examiner may attach such conditions to the granting of the variance as he/she deems necessary to
further the purposes of this ordinance.
E. The floodplain administrator or designee shall maintain the records of all appeal actions and report any
variances to the Federal Emergency Management Agency upon request.
15.68.250 Variance Criteria.
A. In addition to the Criteria outlined in ACC 18.70.025, in reviewing applications for a variance,the
Hearing Examiner shall consider all technical evaluations, all relevant factors, standards specified in other
sections of this ordinance; and:
1. The relationship of the proposed use to the comprehensive plan, growth management
regulations, critical area regulations, the shoreline management program and floodplain management
program for the area;
2. The potential of the proposed development project to destroy or adversely affect a fish and
wildlife habitat conservation area or create an adverse effect to federal, state or locally protected
species or habitat;
3. Is the minimum necessary to grant relief; and,
B. In addition to the Criteria outlined in ACC 18.70.025, no variance shall be granted to the requirements
of this ordinance unless the applicant demonstrates that:
1. The project will not adversely affect features or quality of habitat supporting local, state or
federally protected fish or wildlife;
C. Variances may be requested for new construction, substantial improvements, and other development
upon showing of good and sufficient cause and is minimum necessary, considering flood hazard, to afford relief
provided:
D. Variances shall only be issued:
1. Upon a determination that the granting of a variance will not result in increased flood heights,
additional threats to public safety, extraordinary public expense, create nuisances, cause
fraud on or victimization of the public, or conflict with existing local laws or ordinances;
2. For the repair, rehabilitation,or restoration of historic structures upon a determination that the
proposed repair or rehabilitation will not preclude the structure's continued designation as a
historic structure and the variance is the minimum necessary to preserve the historic character
and design of the structure;
3. Upon a determination that failure to grant the variance would result in exceptional hardship to
the applicant;
4. Upon a showing that the use cannot perform its intended purpose unless it is located or
carried out in close proximity to water. This includes only facilities defined in Section 2 of this
ordinance in the definition of"Functionally Dependent Use."
E. Variances shall not be issued within any floodway if any increase in flood levels during the base flood
discharge would result.
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F. Generally,variances may be issued for new construction and substantial improvements to be erected
on a lot of one-half acre or less in size contiguous to and surrounded by lots with existing structures
constructed below the BFE, provided the procedures of Sections 4 and 5 of this ordinance have been fully
considered.As the lot size increases beyond one-half acre,the technical justification required for issuing the
variance increases.
G. In considering variance applications, the City of Auburn shall consider all technical evaluations, all
relevant factors, all standards specified in other sections of this ordinance, and:
1. The danger that materials may be swept onto other lands to the injury of others;
2. The danger to life and property due to flooding or erosion damage;
3. The susceptibility of the proposed facility and its contents to flood damage and the effect of
such damage on the individual owner;
4. The importance of the services provided by the proposed facility to the community;
5. The necessity to the facility of a waterfront location,where applicable;
6. The availability of alternative locations for the proposed use, which are not subject to flooding
or erosion damage;
7. The compatibility of the proposed use with existing and anticipated development;
8. The relationship of the proposed use to the comprehensive plan and floodplain management
program for that area;
9. The safety of access to the property in time of flood for ordinary and emergency vehicles;
10. The expected heights, velocity, duration, rate of rise, and sediment transport of the
floodwaters expected at the site;
11. The costs of providing governmental services during and after flood conditions, including
maintenance and repair of public utilities and facilities, such as sewer, gas, electrical,water system,
and streets and bridges;
H. Any applicant to whom a variance is granted shall be given written notice over the signature of a
community official that:
1. The issuance of a variance to construct a structure below the Base Flood Elevation will result
in increased premium rates for flood insurance up to amounts as high as$25 for$100 of insurance
coverage, and
2. Such construction below the base flood elevation increases risks to life and property.
The Floodplain Administrator shall maintain a record of all variance actions, including justification for
their issuance.
Section 5. General Development Standards
The provisions of Section 5 shall apply in the Special Flood Hazard Area:
15.68.260 Development and Subdivision Proposals.
This section applies to all development proposals including commercial development, subdivisions, short
subdivisions, preliminary subdivisions, binding site plans, and expansions to manufactured home parks as
defined in Chapter 17.04 ACC.
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A. All development proposals shall be consistent with the need to minimize flood damage.
B. All development proposals shall have utilities and facilities, such as sewer, gas, electrical, and water
systems located and constructed to prevent flood damage.
C. All development proposals shall have adequate drainage provided to avoid exposure to water damage.
D. The proposed subdivision must have one or more new lots in the Special Flood Hazard Area set aside
for open space use through deed restriction, easement, subdivision covenant, or donation to a public agency.
1. In the Special Flood Hazard Area outside the Protected Area, zoning must maintain a low
density of floodplain development.
2. In the Special Flood Hazard Area outside the protected area in which the current zoning is
less than 5 acres must maintain current zoning.
3. The density of development in the portion of the development outside the Special Flood
Hazard Area may be increased to compensate for the amount of land in the Special Flood Hazard
Area preserved as open space in accordance with Chapter 17.25 ACC.
E. If a parcel has a buildable site outside the Special Flood Hazard Area, it shall not be subdivided to
create a new lot that does not have a buildable site outside of the Special Flood Hazard Area. This provision
does not apply to tracts that are to be preserved as open space.
F. All development proposals shall ensure that all subdivisions have at least one access road connected
to land outside the Special Flood Hazard Area with the surface of the road at or above the FPE wherever
possible. Additional access roads may be required based on the number of proposed lots per the current City
of Auburn Engineering Design Standards.
G. The final recorded plat shall include a notice that part of the property is in the SFHA, riparian buffer
zone and/or channel migration area, as appropriate.
H. BFE generation for all development proposals greater than 50 lots or 5 acres,whichever is the lesser.
15.68.270 Site Design.
A. Structures and other development shall be located to avoid flood damage or that adequately mitigates
any identified impacts.
1. If a lot has a buildable site out of the Special Flood Hazard Area, all new structures shall be
located in that area,when possible.
2. If a lot does not have a buildable site out of the Special Flood Hazard Area, all new structures,
pavement, and other development must be sited in the location that has the least impact on habitat by
locating the development as far from the water body as possible or by placing the structure on the
highest portion of the lot.
3. A minimum setback of 15 feet from the Protected Area shall be required for all structures.
4. If the proposed project does not meet the criteria of Section 15.68.270(A)through (B), a
habitat impact assessment shall be conducted pursuant to Section 15.68.440 and, if necessary, a
habitat mitigation plan shall be prepared and implemented pursuant to Section 15.68.450.
B. All new development shall be designed and located to minimize the impact on flood flows,flood
storage, water quality and habitat.
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1. Stormwater and drainage features shall incorporate low impact development techniques, if
technically feasible,that mimic pre-development hydrologic conditions, such as stormwater infiltration,
rain gardens, grass swales,filter strips, disconnected hard surface areas, permeable pavement,
vegetative roof systems, etc. per the City's current SWMM per Chapter 12.04 ACC.
2. If the proposed project will create new hard surfaces so that more than 10 percent of the
portion of the lot in the Special Flood Hazard Area is covered by hard surface,the applicant shall
demonstrate that there will be no net increase in the rate and volume of the stormwater surface runoff
per the maximum extent feasible and as required per the City's current SWMM per ACC 13.48 that
leaves the site or that the adverse impact is mitigated, as provided in Sections 15.68.440 and
15.68.450.
C. The site plan required in Section 15.68.170 shall account for surface drainage to ensure that:
1. Existing and new buildings on the site will be protected from stormwater runoff; and
2. The project will not divert or increase surface water runoff onto neighboring properties.
15.68.280 Hazardous Materials.
A. No new development shall create a threat to public health, public safety or water quality. Chemicals,
explosives, gasoline, propane, buoyant materials, animal wastes,fertilizers, flammable liquids, pollutants, or
other materials that are hazardous, toxic, or a threat to water quality are prohibited from the Special Flood
Hazard Area. This prohibition does not apply to small quantities of these materials kept for normal household
use. This prohibition does not apply to the continued operations of existing facilities and structure, reuse of
existing facilities and structures, or functionally dependent facilities or structures.
B. If the proposed project cannot meet Section 15.68.280(A)of this ordinance, then a habitat impact
assessment must be conducted in accordance with Sections 15.68.440 and 15.68.450.
15.68.290 Critical Facilities.
A. Construction of new critical facilities shall be, to the extent possible, located outside the limits of the
Special Flood Hazard Area.
B. Construction of new critical facilities in the Special Flood Hazard Area shall be permissible if no
feasible alternative site is available, provided;
1. Critical facilities shall have the lowest floor elevated three feet above the base flood elevation
or to the height of the 500-year flood, whichever is higher. If there is no available data on the 500-year
flood, the permit applicants shall develop the needed data in accordance with FEMA mapping
guidelines.
2. Access to and from the critical facility shall be protected to the elevation of the 500-year
floodplain. Access routes elevated to or above the level of the base flood elevation shall be provided to
all critical facilities to the extent possible.
Section 6.Standards for Protection of Structures
15.68.300 Applicability.
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The protection requirements in this section apply to all new structures and substantial improvements,which
include:
A. Construction or placement of a new structure.
B. Reconstruction, rehabilitation, or other improvement that will result in a substantially improved building.
C. Repairs to an existing building that has been substantially damaged regardless of the actual repair
work that is done .
D. Placing a manufactured home on a site.
E. Placing an occupied recreational vehicle or travel trailer on a site for more than 180 days.
15.68.310 Flood Protection Standards.
A. All new structures and substantial improvements shall have the lowest floor, including basement,
elevated to or above the FPE.
B. New construction and substantial improvement of any residential structure in an Unnumbered A zone
for which a BFE is not available and cannot be reasonably obtained shall be reasonably safe from flooding, but
in all cases the lowest floor shall be at least two feet above the Highest Adjacent Grade.
C. The structure shall be aligned parallel with the direction of flood flows where practicable.
D. The structure shall be anchored to prevent flotation,collapse, or lateral movement of the structure
resulting from hydrodynamic and hydrostatic loads including the effects of buoyancy.
E. All manufactured homes shall be anchored to prevent flotation, collapse, or lateral movement, and
shall be installed using methods and practices that minimize flood damage.Anchoring methods may include,
but are not limited to, use of over-the-top or frame ties to ground anchors.
F. All materials below the FPE shall be resistant to flood damage and firmly anchored to prevent flotation.
Materials harmful to aquatic wildlife,such as creosote, are prohibited below the FPE.
G. All new construction and substantial improvements shall be constructed using methods and practices
that minimize flood damage
H. Electrical, heating, ventilation, duct work, plumbing, and air-conditioning equipment and other service
facilities shall be elevated to or above the FPE.Water, sewage, electrical, and other utility lines(excluding
storm drainage facilities) below the FPE shall be constructed so as to minimize water from entering or
accumulating within them during conditioning of flooding.
Fully enclosed areas below the lowest floor that are subject to flooding shall be used only for parking,
limited storage, or building access and shall be designed to automatically equalize hydrostatic flood forces on
exterior walls by allowing for the entry and exit of floodwaters. Designs for meeting this requirement shall either
be certified by a registered professional engineer or licensed architect in the State of Washington and/or meet
or exceed the following minimum criteria:
1. A minimum of two openings having a total net area not less than one square inch for every
square foot of enclosed area subject to flooding shall be provided.
2. The bottom of all openings shall be no higher than one foot above grade.
3. Openings may be equipped with screens, louvers, or other coverings or devices provided that
they permit the automatic entry and exit of floodwaters.
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4. A garage attached to a residential structure, constructed with the garage floor slab below the
BFE, must be designed to allow for the automatic entry and exit of flood waters.
15.68.320 Nonresidential Construction.
New construction and substantial improvement of any commercial, industrial, or other nonresidential structure
shall meet the requirements of subsection A or B below:
A. New construction and substantial improvement of any commercial, industrial or other nonresidential
structure shall meet all of the following requirements:
1. New construction and substantial improvement of any commercial, industrial, or other
nonresidential structure shall have the lowest floor, including basement, elevated one foot or more
above the BFE, or elevated as required by ASCE 24,whichever is greater. Mechanical equipment and
utilities shall be waterproofed or elevated least one foot above the BFE, or as required by ASCE 24,
whichever is greater.
2. If located in an Unnumbered A zone for which a BFE is not available and cannot be
reasonably obtained,the structure shall be reasonably safe from flooding, but in all cases the lowest
floor shall be at least two feet above the Highest Adjacent Grade.
3. If buildings are constructed or substantially improved with fully enclosed areas below the
lowest floor, that are subject to flooding, the areas shall be used only for parking, limited storage, or
building access, and shall be designed to automatically equalize hydrostatic flood forces on exterior
walls by allowing for the entry and exit of floodwaters. Designs for meeting this requirement must either
be certified by a registered professional engineer or architect or must meet or exceed the following
minimum criteria:
a. Have a minimum of two openings with a total net area of not less than one square
inch for every square foot of enclosed area subject to flooding.
b. The bottom of all openings shall be no higher than one foot above grade.
c. Openings may be equipped with screens, louvers, valves, or other coverings or
devices provided that they permit the automatic entry and exit of floodwater.
4. Alternatively, a registered engineer or architect may design and certify engineered openings.
B. If the requirements of Section 15.68.320(A) are not met, then new construction and substantial
improvement of any commercial, industrial or other nonresidential structure shall meet all of the following
requirements:
1. Together with attendant utility and sanitary facilities, be dry floodproofed so that below one
foot or more above the base flood level the structure is watertight with walls substantially impermeable
to the passage of water or dry floodproofed to the elevation required by ASCE 24,whichever is
greater;
2. Have structural components capable of resisting hydrostatic and hydrodynamic loads and
effects of buoyancy;
3. Be certified by a registered professional engineer or architect that the design and methods of
construction are in accordance with accepted standards of practice for meeting provisions of this
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subsection based on their development and/or review of the structural design, specifications and
plans. Such certifications shall be provided to the official as set forth in Section 15.68.220(B);
15.68.330 Manufactured Homes.
All manufactured homes to be placed or substantially improved on sites shall be:
A. Elevated on a permanent foundation in accordance with Section 15.68.310(A)and
B. Securely anchored to an adequately anchored foundation system to resist flotation, collapse and
lateral movement. Methods of anchoring may include, but are not to be limited to, use of over-the-top or frame
ties to ground anchors. This requirement is in addition to other applicable anchoring requirements for resisting
wind forces.
C. If manufactured homes are constructed or substantially improved with fully enclosed areas below
the lowest floor, the areas shall be used solely for parking of vehicles, building access, or storage.
15.68.340 Recreational Vehicles.
Recreational vehicles placed on sites shall:
A. Be on the site for fewer than 180 consecutive days, or
B. Be fully licensed and ready for highway use, on their wheels or jacking system, attached to the site
only by quick disconnect type utilities and security devices, and have no permanently attached addition; or
C. Meet the requirements of Section 15.68.340 and the anchoring requirements for manufactured homes
in Section 15.68.330.
15.68.350 Appurtenant Structures.
A structure which is on the same parcel of property as the principle structure and the use of which is incidental
to the use of the principle structure and is not used for human habitation may be exempt from the elevation
requirements of Section 15.68.310(A), provided:
A. It is used only for parking or storage;
B. It is constructed and placed on the building site so as to offer minimum resistance to the flow of
floodwaters;
C. It is anchored to prevent flotation which may result in damage to other structures;
D. All portions of the structure below the FPE must be constructed of flood-resistant materials;
E. Service utilities such as electrical and heating equipment meet the standards of Section 15.68.310(F)
and Section 15.68.360;
F. It has openings to allow free flowage of water that meet the criteria in Section 15.68.310(1);
G. The project meets all the other requirements of this ordinance, including Section 7 and 15.68.410.
15.68.360 Utilities.
A. All new and replacement water supply systems shall be designed to minimize or eliminate infiltration of
flood waters into the system;
B. New water wells shall be located outside the floodway and shall be protected to the FPE;
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C. New and replacement sanitary sewage systems shall be designed to minimize or eliminate infiltration
of flood waters into the systems and discharges from the systems into the floodwaters;
D. Onsite waste disposal systems shall be located to avoid impairment to them or contamination from
them during flooding. A habitat impact assessment shall be conducted in accordance with Section 15.68.440 as
a condition of approval of an onsite waste disposal system to be located in the Special Flood Hazard Area.
Section 7.Standards for Habitat Protection
The provisions of this Section shall apply in the Special Flood Hazard Area and channel migration zone.
15.68.370 Non-Development Activities.
Activities that do not meet the definition of"development"are allowed in the Special Flood Hazard Area and
Protected Area without the need for a floodplain development permit under this ordinance, provided all other
Federal, State and local requirements are met. The following are examples of activities not considered
development or"unnatural changes to improved or unimproved real estate".
A. Routine maintenance of landscaping that does not involve grading, excavation or filling;
B. Removal of noxious weeds and hazard trees and replacement of non-native vegetation with native
vegetation;
C. Normal maintenance of structures, such as re-roofing and replacing siding, provided such work does
not qualify as a substantial improvement;
D. Normal maintenance of above ground utilities and facilities, such as replacing downed power lines and
utility poles;
E. Underground and above ground utility work located in previously disturbed areas,with no significant
vegetation impacts, and will have no appreciable change in grade;
F. Normal maintenance and preservation of public streets and private streets or parking lots(with
approval of Floodplain Administrator) , including, but not limited to filling potholes, patching, crack seal, chip
seal, repaving and installing signs and traffic signs, traffic control devices, striping/channelization, pavement
markings, repair/replacement of sidewalk/curb and gutter,ADA improvements, non-motorized improvements,
repair of guardrails, repair of retaining walls, management of hazardous trees,fencing repair, lighting repair, but
not including expansion of paved areas;
G. Public street improvements with no significant vegetation impacts, and no appreciable change in
grade;
H. Normal maintenance of a levee or other flood control facility prescribed in the operations and
maintenance plan for the levee or flood control facility are allowed in the Special Flood Hazard Area without the
need for a floodplain development permit. Normal maintenance does not include repair from flood damage,
expansion of the prism, expansion of the face or the toe or addition for protection on the face or toe with rock
armor; and
Plowing and other normal flood protection practices (other than structures or filling) on farms in the
Special Flood Hazard Area and in existence as of the effective date of this ordinance do not require a floodplain
development permit. Clearing additional land for agriculture after the date of this ordinance will require a
floodplain development permit and a Habitat Assessment.
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15.68.380 Activities Allowed with a Floodplain Development Permit.
The following activities are allowed in the Special Flood Hazard Area without the analysis required in Section
15.68.410 or the habitat impact assessment required under Section 15.68.440, provided that all other
requirements of this ordinance are met, including obtaining a floodplain development permit:
A. Repairs or remodeling of an existing structure, provided that the repairs or remodeling are not a
substantial improvement or a repair of substantial damage.
B. Expansion or reconstruction of an existing structure that is no greater than ten percent beyond its
existing footprint, provided that the repairs or remodeling are not a substantial improvement or repair of
substantial damage. If the structure is in the floodway,there shall be no change in the structure's dimensions
perpendicular to flow and a no rise analysis and certification must be provided, even if he change in dimensions
is parallel to flow.
C. Activities with the sole purpose of creating, restoring or enhancing natural functions associated with
floodplains, streams, lakes, estuaries, marine areas, habitat and riparian areas that meet Federal and State
standards, provided the activities do not include structures, grading,fill, or hard surfaces.
D. Development of open space and recreational facilities such as parks,trails and hunting grounds, that
do not include structures,fill, hard surfaces or removal of more than five percent of the native vegetation on
that portion of the property in the Special Flood Hazard Area.
E. Repairs to onsite Septic Systems provided the ground disturbance is the minimum necessary and best
management practices (BMP's)to prevent stormwater runoff and soil erosion are used.
15.68.390 Other Activities.
All other activities listed in Sections 15.68.370 or 15.68.380 that are allowed by Title 18 (Zoning)of the Auburn
City Code are allowed, provided they meet all the other requirements of this ordinance, including the analysis
required under Section 15.68.420, 15.68.430, and the habitat impact assessment required under Section
15.68.440, and a floodplain development permit is issued.
15.68.400 Native Vegetation.
The site plan required in the Floodplain Development Application Packet shall show existing native vegetation.
A. Within the riparian buffer zone, native vegetation shall be left undisturbed, except as provided in
Sections 15.68.370 and 15.68.380(C).
B. Outside the riparian buffer zone, removal of native vegetation shall not exceed 35 percent of the
surface area of the portion of the site in the Special Flood Hazard Area. Native vegetation in the riparian buffer
zone portion of the property can be counted toward this requirement.
C. If the proposed project does not meet the criteria of Sections 15.68.400(A) and (B), a habitat impact
assessment shall be conducted pursuant to Section 15.68.440 and, if necessary, a habitat mitigation plan shall
be prepared and implemented pursuant to Section 15.68.450.
15.68.410FIoodway Standards.
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A. In addition to the other requirements of this ordinance, a project to develop in the floodway as
delineated pursuant to Sections 15.68.130(C), 15.68.130(D)or 15.68.150(E) shall meet the following criteria:
1. The applicant shall provide a certification by a registered professional engineer licensed in the
State of Washington demonstrating through hydrologic and hydraulic analyses performed in
accordance with standard engineering practices that the proposed development would not result in any
increase in flood levels during the occurrence of the base flood discharge.
2. Construction or reconstruction of residential structures is prohibited within designated
floodways, except for the following. The following exceptions must still meet all other requirements in
the ordinance, including Section 15.68.410(A)(1).
a. Repairs, reconstruction, or improvements to a residential structure that do not
increase the ground floor area, providing the cost of which does not exceed 50 percent of the
market value of the structure either, (1) before the repair, or reconstruction is started, or(2) if
the structure has been damaged, and is being restored, before the damage occurred. Any
project for improvement of a structure to correct existing violations of State or local health,
sanitary, or safety code specifications that have been identified by a local code enforcement
official, and which are the minimum necessary to assure safe living conditions, or to an
historic structure, may be excluded from the 50 percent calculation;
b. Repairs, reconstruction, replacement, or improvements to existing farmhouse
structures located in designated floodways and that are located on lands designated as
agricultural lands of long-term commercial significance under RCW 36.70A.170 may be
permitted subject to the following:
The new farmhouse is a replacement for an existing farmhouse on the same
farm site;
ii. There is no potential building site for a replacement farmhouse on the same
farm outside the designated floodway;
iii. Repairs, reconstruction, or improvements to a farmhouse shall not increase
the total square footage of encroachment of the existing farmhouse;
iv. A replacement farmhouse shall not exceed the total square footage of
encroachment of the farmhouse it is replacing;
v. A farmhouse being replaced shall be removed, in its entirety, including
foundation,from the floodway within ninety days after occupancy of a new farmhouse;
vi. For substantial improvements and replacement farmhouses, the elevation of
the lowest floor of the improvement and farmhouse respectively, including basement,
is a minimum of one foot higher than the BFE;
vii. New and replacement water supply systems are designed to eliminate or
minimize infiltration of floodwaters into the system;
viii. New and replacement sanitary sewerage systems are designed and located
to eliminate or minimize infiltration of floodwater into the system and discharge from
the system into the floodwaters; and
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ix. All other utilities and connections to public utilities are designed, constructed,
and located to eliminate or minimize flood damage.
c. For all substantially damaged residential structures, other than farmhouses, located
in a designated floodway,the Floodplain Administrator may make a written request that the
Department of Ecology assess the risk of harm to life and property posed by the specific
conditions of the floodway. Based on analysis of depth, velocity,flood-related erosion,
channel migration, debris load potential, and flood warning capability, the Department of
Ecology may exercise best professional judgment in recommending to the local permitting
authority repair, replacement, or relocation of a substantially damaged structure consistent
with WAC 173-158-076.The property owner shall be responsible for submitting to the local
government and the Department of Ecology any information necessary to complete the
assessment.Without a favorable recommendation from the department for the repair or
replacement of a substantially damaged residential structure located in the regulatory
floodway, no repair or replacement is allowed per WAC 173-158-070(1).
d. Before the repair, replacement,or reconstruction is started, all requirements of the
NFIP,the state requirements adopted pursuant to 86.16 RCW, and all applicable local
regulations must be satisfied. In addition,the following conditions must be met:
There is no potential safe building location for the replacement residential
structure on the same property outside the regulatory floodway.
ii. A replacement residential structure is a residential structure built as a
substitute for a legally existing residential structure of equivalent use and size.
iii. Repairs, reconstruction, or replacement of a residential structure shall not
increase the total square footage of floodway encroachment.
iv. The elevation of the lowest floor of the substantially damaged or replacement
residential structure is a minimum of one foot higher than the BFE.
v. New and replacement water supply systems are designed to eliminate or
minimize infiltration of floodwater into the system.
vi. New and replacement sanitary sewerage systems are designed and located
to eliminate or minimize infiltration of floodwater into the system and discharge from
the system into the floodwaters.
vii. All other utilities and connections to public utilities are designed, constructed,
and located to eliminate or minimize flood damage.
e. Repairs, reconstruction, or improvements to residential structures identified as
historic structures that do not increase the building's dimensions.
B. In riverine Special Flood Hazard Areas where a floodway has not been delineated pursuant to
Sections 15.68.130(C), 15.68.130(D)or 15.68.150(E), the applicant for a project to develop in the SFHA shall
provide a certification by a registered professional engineer in the State of Washington demonstrating through
hydrologic and hydraulic analyses performed in accordance with standard engineering practices that the
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proposed development and all other past or future similar developments would not cumulatively result in an
increase of flood levels during the occurrence of the base flood discharge by more than one-half foot.
15.68.420 Standards for Shallow Flooding Areas (AO Zones)
Shallow flooding areas appear on FIRMs as AO zones with depth designations. The base flood depths in these
zones range from 1 to 3 feet above ground where a clearly defined channel does not exist, or where the path of
flooding is unpredictable and where velocity flow may be evident. Such flooding is usually characterized as
sheet flow. In addition to other provisions in this code, the following additional provisions also apply in AO
zones.
A. New construction and substantial improvements of residential structures and manufactured homes
within AO zones shall have the lowest floor(including basement and mechanical equipment)elevated above
the highest adjacent grade to the structure, one foot or more above the depth number specified in feet on the
community's FIRM (at least two feet above the highest adjacent grade to the structure if no depth number is
specified).
B. New construction and substantial improvements of nonresidential structures within AO zones shall
either:
1. Have the lowest floor(including basement)elevated above the highest adjacent grade of the
building site, one foot or more above the depth number specified on the FIRM (at least two feet if no
depth number is specified); or
2. Together with attendant utility and sanitary facilities, be completely flood proofed to or above
that level so that any space below that level is watertight with walls substantially impermeable to the
passage of water and with structural components having the capability of resisting hydrostatic and
hydrodynamic loads and effects of buoyancy. If this method is used, compliance shall be certified by a
registered professional engineer, or architect as in Section 15.68.310(1).
C. Require adequate drainage paths around structures on slopes to guide floodwaters around and away
from proposed structures.
D. Recreational vehicles placed on sites within AO zones on the community's FIRM either:
1. Be on the site for fewer than 180 consecutive days, or
2. Be fully licensed and ready for highway use, on its wheels or jacking system, is attached to the site
only by quick disconnect type utilities and security devices, and has no permanently attached
additions; or
3. Meet the requirements of subsections(1)and (3)above and the anchoring requirements for
manufactured homes (Section 15.68.330(B)).
15.68.430 Compensatory Storage.
New development shall not reduce the effective flood storage volume of the Special Flood Hazard Area.A
development proposal shall provide compensatory storage if grading or other activity eliminates any effective
flood storage volume. Compensatory storage shall:
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A. Provide equivalent volumes at equivalent elevations to that being displaced. For this purpose,
"equivalent elevation" means having similar relationship to ordinary high water mark and to the best available
10-year, 50-year and 100-year water surface profiles.
B. Be hydraulically connected to the source of flooding.
C. Provide compensatory storage in the same construction season as when the displacement of flood
storage volume occurs and before the flood season begins.
D. The newly created storage area shall be graded and vegetated to allow fish access during flood events
without creating fish stranding sites.
15.68.440 Habitat Impact Assessment.
Unless allowed under Sections 15.68.370 and 15.68.380, a permit application to develop in the Special Flood
Hazard Area shall include an assessment of the impact of the project on federal, state or locally protected
species and habitat, water quality and aquatic and riparian habitat. The assessment shall be:
A. A Biological Evaluation or Biological Assessment developed per 50 C.F.R., Subsection 402.12 to
initiate Federal Interagency consultation under Endangered Species Act Section 7.a.2; or,
B. Documentation that the activity fits within Section 4.d of the Endangered Species Act; or,
C. Documentation that the activity fits within a Habitat Conservation Plan approved pursuant to Section
10 of the Endangered Species Act,where any such assessment has been prepared or is otherwise made
available; or
D. An assessment prepared in accordance with Regional Guidance for Floodplain Habitat Assessment
and Mitigation, FEMA Region X, 2013.The assessment shall determine if the project would adversely affect:
1. Species that are Federal, state or local listed as threatened or endangered.
2. The primary constituent elements for critical habitat when delineated, including but not limited
to water quality,water quantity,flood volumes,flood velocities, spawning substrate, and/or floodplain
refugia for listed salmonids.
3. Essential Fish Habitat designated by the National Marine Fisheries Service.
4. Fish and wildlife habitat conservation areas.
5. Other protected areas and elements necessary for species conservation.
15.68.450 Habitat Mitigation Plan.
A. If the assessment conducted under Section 15.68.440 concludes the project is expected to have an
adverse effect on water quality and/or aquatic or riparian habitat or habitat function,the applicant shall provide
a plan to mitigate those impacts, in accordance with Regional Guidance for Floodplain Habitat Assessment and
Mitigation, FEMA Region X, 2013.
1. If the USFWS or NMFS issues an Incidental Take Permit under Section 10 of the Endangered
Species Act or a Biological Opinion under Section 7 of the Endangered Species Act; then it can be
considered to quality as a plan to mitigate those impacts.
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2. If the project is located in the Protected Area,the mitigation plan shall stipulate avoidance
measures as are needed to ensure that there is no adverse effect during any phase of the project. No
compensatory mitigation is allowed in the Protected Area.
3. If the project is located outside the Protected Area,the mitigation plan shall include such
avoidance, minimization, restoration, or compensation measures so that indirect adverse effects of
development are mitigated such that equivalent or better habitat protection is provided for the following
functions:
a. Stormwater: Reduce flood volumes and stormwater runoff from new development by
ensuring that increased volumes of stormwater reach the river at the same frequency, timing
and duration as historical runoff. Low Impact Development(LID) is required to be incorporated
as described in Section 15.68.270(B).
b. Riparian Vegetation: Maintain or replace riparian function by providing equivalent
area, diversity, and function of riparian vegetation as currently exists on the site. Riparian
retention requirements are outlined in ACC 15.68.400.
c. Hyporheic Zones: No activity is allowed that interferes with the natural exchange of
flow between surface water, groundwater and hyporheic zone, however, natural hyporheic
exchange may be enhanced or restored.
d. Wetlands:Wetland function must be maintained or replaced by providing equivalent
function.
e. Large Woody Debris:Any large woody debris (LWD) removed from the floodplain
must be replaced in kind, replicating or improving the quantity, size, and species of the
existing LWD per Washington Department of Fish and Wildlife Aquatic Habitat Guidelines.
4. No new stream crossings are allowed outside the Protected Area unless approval has been
obtained as stated in Section 15.68.460(A).
B. The plan's habitat mitigation activities shall be incorporated into the proposed project. The floodplain
development permit shall be based on the redesigned project and its mitigation components.
C. As required in Section 15.68.230, the floodplain administrator or designee shall not issue a certificate
of occupancy or final permits until all work identified in the Habitat Assessment and mitigation plan has been
completed or the applicant has provided the necessary assurance that unfinished portions of the project will be
completed, in accordance with Section 15.68.230(A).
D. Third-Party Review. For the habitat impact assessment required in Subsection 15.68.440 or the habitat
mitigation plan required in this section,the city may require third-party review when the professional opinions of
the applicant's representative and the city's reviewers cannot be reconciled. Third-party review requires the
applicant's habitat impact assessment, habitat mitigation plan, and/or additional technical studies to be
reviewed by an independent third party, paid for by the applicant but hired by the city. Third-party review shall
be conducted by a qualified consultant as defined in the Floodplain Habitat Assessment and Mitigation
Regional Guidance, FEMA Region X, 2013.
15.68.460 Alteration of Watercourses and SFHA Boundaries.
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A. In addition to the other requirements in Chapter 15.68, if a project will alter or relocate boundaries of
the SFHA, then the applicant shall also submit a request for a Conditional Letter of Map Revision (CLOMR),
where required by FEMA with engineering documentation and analysis regarding the proposed change. The
project will not be approved unless FEMA issues the CLOMR (which requires Endangered Species Act
consultation)and the provisions of the letter are made part of the permit requirements. If the change to the BFE
or boundaries of the SFHA would normally require a Letter of Map Change, then the project proponent shall
initiate, and receive approval of, a Conditional Letter of Map Revision (CLOMR) prior to approval of the
development permit. The project shall be constructed in a manner consistent with the approved CLOMR.
B. If a CLOMR application is made,then the project proponent shall also supply the full CLOMR
documentation package to the Floodplain Administrator to be attached to the floodplain development permit,
including all required property owner notifications.
C. The floodplain administrator or designee shall notify adjacent communities and the Washington
Department of Ecology prior to any alteration or relocation of a watercourse, and submit evidence of such
notification to the Federal Insurance Administrator;
D. Assure that the flood-carrying capacity of the altered or relocated portion of the watercourse is
maintained. If the maintenance program does not call for cutting of native vegetation,the system shall be
oversized at the time of construction to compensate for said vegetation growth or any other natural factor that
may need future maintenance.
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