HomeMy WebLinkAboutO-1339 - Repeals and replaces Ch. 16.32, flood hazard areas (Repealed by 2852)'...f ,
CIT Y 0 F MAR Y S V ILL E
Marysville,Washington
ORDINANCE NO.
AN ORDINANCE OF THE CITY OF MARYSVILLE REPEALING
CHAPTER 16.32 OF THE ~~RYSVILLE MUNICIPAL CODE
AND ENACTING A NEW CHAPTER RELATING TO FLOOD
HAZARD AREAS
THE CITY COUNCIL OF THE CITY OF MARYSVILLE,WASHINGTON,
DO ORDAIN AS FOLLOWS:
Chapter 16.32 of the Marysville Municipal Code,entitled
"Construction in Flood Hazard Areas,"and all sections thereof,
are hereby REPEALED for the reason that the same are superseded
by the following provisions of this ordinance.
A new Chapter 16.32 of the Marysville Municipal Code
entitled "Flood Plain Management"is hereby enacted with the
following provisions:
16.32.010 Statement of Purpose.It is the purpose of
this chapter 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:
(1)To protect human life and health;
(2)To minimize expenditure of pUblic money and costly
flood control projects;
(3)To minimize the need for rescue and relief efforts
associated with flooding and generally undertaken
at the expense of the general public;
(4)To minimize prolonged business interruptions;
(5)To minimize damage to public facilities and util-
ities such as water and gas mains,electric,tele-
phone and sewer lines,streets and bridges located
in areas of special flood hazard;
(6)To help maintain a stable tax base by providing
for the sound use and development of areas of
special flood hazard so as to minimize future
flood blight areas;
Ordinance - 1
(7)To ensure that potential buyers are notified
that property is in an area of special flood
hazard;and
(8)To ensure that those who occupy the areas of
special flood hazard assume responsiblity for
their actions.
16.32.020 Definitions.Unless specifically defined
below,words or phrases used in this chapter shall be interpreted
so as to give them the meaning they have in common usage and to'
give this chapter its most reasonable application.
(1)"Appeal"means a request for a review of the
Building Official's interpretation of any pro-
vision of this chapter or a request for a var-
iance.
(2)"Area of Shallow Flooding"means a designated AO
or AH Zone on the Flood Insurance Rate Map (FIRM).
The base flood depths range from one to three feet;
a clearly defined channel does not exist;the path
of flooding is unpredictable and indeterminate;and
velocity flow may be evident.
(3)"Area of Special Flood Hazard"means the land in
the flood plain within a community sUbject to a
one percent (1%)or greater chance of flooding in
any given year.
(4)"Base Flood"means the flood having a one percent
(1%)chance of being equalled or exceeded in any
given year.
(5)"Development"means any man-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 located within the area of special flood
hazard.
(6)"Existing Mobile Home Park or Hobile Home Subdivision"
means a parcel (or contiguous parcels)of land
divided into two or more mobile home lots for rent
or sale for which the construction of facilities
for servicing the lot on which the mobile home is
to be affixed (including,at a minimum,the instal-
lation of utilities,either final site grading or
the pouring of concrete pads,and the construction
of streets)is completed before the effective date
of this chapter.
Ordinance - 2
"',..
(7)"Expansion to an Existing Mobile Home Park or
Mobile Home Subdivision"means the preparation of
additional sites by the construction of facilities
for servicing the lots on which the mobile homes
are to be affixed (including the installation of
utilities,either final site grading or.pouring of
concrete pads,or the construction of streets).
(8)"Flood"or "Flooding"means a general and temporary
condition of partial or complete inundation of nor-
mally dry land areas from:
(a)The overflow of inland or tidal waters;and/or
(b)The unusual and rapid accumulation of runoff
of surface waters from any source.
(9)"Flood Insurance Rate Map (FIRM)"means the official
map on which the Federal Insurance Administration
has delineated both the areas of special flood haz-
ards and the risk premium zones applicable to the
community.
(10)"Flood Insurance Study"means the official report
provided by the Federal Insurance Administration
that includes flood profiles,the ,Flood Boundary-
Floodway Map,and the water surface elevation of
the base flood.
(11)"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 one foot.
(12)"Mobile Home"means a structure that is transport-
able in one or more sections,built on a permanent
chassis,and designed to be used with or without
a permanent foundation when connected to the required
utilities.It does not include recreational vehi-
cles or travel trailers.
(13)"New Construction"means structures for which the
"start of construction"commenced on or after the
effective date of this chapter.
(14)"New Mobile Home Park or Mobile Home Subdivision"
means a parcel (or contiguous parcels)of land
divided into two or more mobile home lots for rent
Ordinance - 3
~,
or sale for which the construction of facilities
for servicing the lot (including,at a minimum,
the installation of utilities,either final site
grading or the pouring of concrete pads,and the
construction of streets)is completed on or after
the effective date of this chapter.
(15)"Start of Construction"means the first placement
of permanent construction of a structure (other
than .a mobile home)on a site such as the pouring
of slabs or footings or any work beyond the stage
of excavation.Permanent construction does not
include land preparations,such as clearing,grad-
ing,and filling,nor does it include the instal-
lation 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 as part of
the main structure.For a structure (other than
a mobile home)without a basement or poured footings,
the "start of construction"includes the first per-
manent framing or assembly of the structure or any
part thereof on its piling or foundation.For
mobile homes not within a mobile home park or mobile
home subdivision,,"start of construction"means
the affixing of the mobile home to its permanent
site.For mobile homes within mobile home parks
or mobile home SUbdivisions,"start of construction"
is the date on which the construction of facilities
for servicing the site on which the mobile home is
to be affixed (including,at a minimum,the con-
struction of streets,either final site grading or
the pouring of concrete pads,and installation of
utilities)is completed.
(16)"Structure"means a walled and roofed building
or mobile home that is principally above ground.
(17)"Substantial Improvement"means any repair,recon-
struction,or improvement of a structure,the cost
of which equals or exceeds fifty percent (50%)of
the market value of the structure either:
(a)before the improvement or repair is started;or
(b)if the structure has been damaged and is being
restored,before the damage occurred.For the
Ordinance - 4
purposes of this definition "substantial
improvement"is considered to occur when
the first alteration of any wall,ceiling,
floor,or other structural part of the
building commences,whether or not that
alteration affects the external dimensions
of the structure.
The term does not,however,include either:
(a)any project for improvement of a structure
to comply with existing state or local
health,sanitary,or safety code specifi-
cations which are solely necessary to
assure safe living conditions;or
(b)any alteration of a structure listed on the
National Register of Historic Places or a
State Inventory of Historic Places.
(18)"Variance"means a grant of relief from the
requirements of this chapter which permits con-
.struction in a manner that would otherwise be
prohibited by this chapter.
GENERAL PROVISIONS
16.32.030 Lands to Which this Chapter Applies.This
chapter shall apply to all areas of special flood hazards within
the jurisdiction of the City of Marysville.
16.32.040 Basis for Establishing the Areas of Special
Flood Hazard.The areas of special flood hazard identified by
the Federal Insurance Administration in a scientific and engineer-
ing report entitled "The Flood Insurance Study for the City of
Marysville"dated February 15,1984,with accompanying Flood
Insurance Maps is hereby adopted by reference and declared to
be a part of this chapter.The Flood Insurance Study is on file
at Marysville City Hall,514 Delta Avenue,Marysville,Washington.
16.32.050 Penalties for Noncompliance.No structure
or land shall hereafter be constructed,located,extended,con-
verted,or altered without full compliance with the terms
of this chapter and other applicable regulations.Violation of
the provisions of this chapter by failure to comply with any
of its requirements (including violat~ons of conditions and safe-
guards established in connection with conditions)shall con-
stitute a misdemeanor.Any person who violates this chapter or
fails to comply with any of its requirements shall,upon con-
viction thereof,be fined not more that $300.00 for each viola-
tion,and in addition shall pay all costs and expenses involved
Ordinance - 5
'..
in the case.Nothing herein contained shall prevent the City
from taking such other lawful action as is necessary to pre-
vent or remedy any violation.
16.32.060 Abrogation and Greater Restrictions.This
chapter is not intended to repeal,abrogate,or impair any exist-
ing easements,covenants,or deed restrictions.However,where
this chapter and another chapter,easement,covenant,or deed
restriction conflict or overlap,whichever imposes the more
stringent restrictions shall prevail.
16.32.070 Interpretation.In the interpretation and
application of this chapter,all provisions shall be:
(1)Considered as minimum requirements;
(2)Liberally construed in favor of the governing
body;
(3)Deemed neither to limit nor repeal any other
powers granted under State statutes.
16.32.080 Warning and Disclaimer of Liability.The
degree of flood protection required by this chapter is consid-
ered reasonable for regulatory purposes and is based on scien-
tific and engineering considerations.Larger floods can and will
occur on rare occasions.Flood heights may be increased by man-
made or natural causes.This chapter does not imply that land
outside the areas of special flood hazards or uses permitted
within such areas will be free from flooding or flood damages.
This chapter shall not create liability on the part of the City
of Marysville,any officer or employee thereof,or the Federal
Insurance Administration,for any flood damages that result
from reliance on this chapter or any administrative decision
lawfully made thereunder.
ADMINISTRATION
16.32.090 Establishment of Development Permit.A
development permit shall be obtained before construction or
development begins within any area of special flood hazard
established in Section 16.32.040.The permit shall be for all
structures,including mobile homes,as set forth in the "Defini-
tions,"and for all other development,including fill and other
activities,also as set forth in the "Definitions."Applica-
tion for a development permit shall be made on forms furnished
by the Building Official and may include,but not be limited to:
plans in duplicate drawn to scale showing the nature,location,
dimensions,and elevations of the area in question;existing or
proposed structures,fill,storage of materials,drainage facil-
Ordinance - 6
ities,and the location of the foregoing.Specifically,the follow-
ing information is required:
(1)Elevation in relation to mean sea level,of the
lowest floor (including basement)of all struc-
tures;
(2)Elevation in relation to mean sea level to which
any structure has been floodproofed;
(3)Certification by a registered professional engin-
eer or architect that the floodproofing methods
for any nonresidential structure meet the flood-
proofing criteria in Section 16.32.160;and
(4)Description of the extent to which a watercourse
will be altered or relocated as a result of the
proposed development.
16.32.100 Designation of the Building Official.The
Building Official'is hereby appointed to administer and implement
this chapter by granting or denying development permit applica-
tions in accordance with its provisions.
16.32.110 Duties and Responsibilities of Building
Official.Duties of the Building Official shall include,but not
be limited to:
A.:Permit Review
(1)Review all development permits to deter-
mine that the permit requirements of this
chapter have been satisfied.
(2)Review all development permits to deter-
mine that all necessary permits have been
obtained from those Federal,State or
local governmental agencies from which
prior approval is required.
(3)Review all development permits in the area
of special flood hazard,except in the coastal
high hazard area,'to determine if the pro-
posed development adversely affects the flood-
carrying capacity of the area of special
flood hazard.For the purposes of this chap-
ter,"adversely affects"means that the cum-
ulative effect of the proposed development
when combined with all other existing and
anticipated development will increase the
Ordinance - 7
B.
C.
D.
Ordinance - 8
water surface elevation of the base flood
more than one foot at any point.
Use of Other Base Fl09d Data.When
base flood elevation data has not been pro-
vided in accordance with Section 16.32.040,
Basis for Establishing the Areas of Special
Flood Hazard,the Building Official may ~btain,
review,and reasonably utilize any base flood
elevation data available from a Federal,State
or other source,in order to administer Section
l6.32.160(A),Specific Standards,Residential Con-
Struction,and Section 16.32.l601B),S~ecific
Standards,Nonresidential Construction.
Information'to be Obtained and l-1aintained.
(1)Obtain and record the actual elevation (in
relation to mean sea level)of the lowest
floor (including basement)of all new or
substantially improved structures,and
whether or not the structure contains a
basement.
(2)For all new or substantially improved
floodproofed structures:
(i)verify and record the actual eleva-
tion (in relation to mean sea level);
and
(ii)maintain the floodproofing certifi-
cations required in Section 16.32.090(3).
(3)Maintain for public inspection all records
pertaining to the provisions of this chapter.
Alteration of Watercourses.
(1)Notify adjacent communities and the Washington
State Department of Ecology prior to any alter-
ation or relocation of a watercourse,and sub-
mit evidence of such notification to the Fed-
eral Insurance Administration.
(2)Require that maintenance is provided within
the altered or relocated portion of said water-
course so that the flood carrying capacity is
not diminished.
E.Interpretation of FIRM Boundaries.
Make interpretations,where needed;-as to exact
location of the boundaries of the areas of
special flood hazards (for example,where
there appears to be a conflict between a mapped
boundary and actual field conditions).The per-
son contesting the location of the boundary shall
be given a reasonable opportunity to appeal the
interpretation as provided in Section 16.32.120.
VARIANCE PROCEDURE
16.32.120 _Appeal Board.
(1)The City Council shall hear and decide appeals
and requests for'variances from the require-
ments of this chapter.
(2)The City Council shall hear and decide appeals
when it is alleged there is an error in any
requirement,decision or determination made
by the Building Official in the enforcement
or administation of this chapter.
(3)Those aggrieved by the decision of the City
Council,or any taxpayer,may appeal such
decision to the Snohomish County Superior
Court,as provided by law.
(4)In passing upon such applications,the City
Council shall consider all technical evalu-
ations,all relevant factors,standards speci-
fied in other sections of this chapter,and:
(i)the danger that materials may be swept
onto other lands to the injury of
others;
(ii)the danger to life and property due to
flooding or erosion damage;
(iii)The susceptibility of the proposed
facility and its contents to flood
damage and the effect of such on the
individual owner;
(iv)the importance of the services pro-
vided by the proposed facility to the
community;
Ordinance -9
Ordinance -10
(v)the necessity to the facility of a
waterfront location,where applicable;
(vi)the availability of alternative loca-
tions for the proposed·use which are
not subject to flooding or erosion
damage;
(vii)the compatibility of the proposed use
with existing and anticipated develop-
ment;
(viii)the relationship of the proposed use
to the Comprehensive Plan and Flood
Plain Management Program for that area;
(ix)the safety or access to the property
in times of flood for ordinary emer-
gency vehicles;
(x)the expected heights,velocity,dura-
tion,rate of rise,and sediment trans-
port of the flood waters and the effects
of the wave action,if applicable,
expected at the site;and
(xi)the costs of providing governmental
services during and after flood con-
ditions,including maintenance and
repair of public utilities and facil-
ities such as sewer,gas,electrical,
and water systems,and streets and
bridges.
(5)Generally,the only condition under which a
variance may be issued is for new construc-
tion and substantial improvements to be erected
on a lot of one-half acre or less in size con-
tiguous to and surrounded by lots with exist-
ing structures constructed below the base flood
level,providing items (i-xi)in Section
16.32.120(4)have been fully considered.As
the lot size increases beyond the one-half
acre,the technical justification required
for issuing the variance increases.
(6)Upon consideration of the factors of Section
16.32.12D(4)and the purposes of this chapter,
the City Council may attach such conditions
to the granting of variances as it deems nec-
essary to further the purposes of this chapter.
(7)The Building Official shall maintain the
records of all appeal actions and report
any variances to the Federal Insurance
Administration upon request.
16.32.130 Conditions for Variances.
(1)Variances may be issued for the reconstruc-
tion,rehabilitation,.or restoration of
structures listed on the National Register
of Historic Places or the State Inventory
of Historic Places,without regard to the
procedures set forth in the remainder of
this section.
(2)Variances shall not be issued within a
designated floodway if any increase in
flood levels during the base flood dis-
charge would result.
(3)Variances shall only be issued upon a deter-
mination that the variance is the minimum
necessary,considering the flood hazard,to
afford relief.
(4)Variances shall only be issued upon:
(i)a showing of good and sufficient
cause;
(ii)a determination that failure to
grant the variance would result in
exceptional hardship to the applicant i
(iii)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 as
identified in Section 16.32.120(4),
or conflict with existing local laws
or ordinances.
(5)Any applicant to whom a variance is granted
shall be given written notice that the struc-
ture will be permitted to be built with a
lowest floor elevation below the base flood
elevation and that the cost of flood insur-
ance will be commensurate with the increased
risk resulting from the reduced lowest floor
elevation.
Ordinance -11
PROVISIONS FOR FLOOD HAZARD PROTECTION
16.32.140 General Standards.In all areas of special
flood hazards,the following stardardsare required:
A.Anchoring:.
(1)All new construction and substantial improve-
ments shall be anchored to prevent flotation,
collapse,or lateral movement of the structure.
(2)All mobile homes shall be anchored to resist
flotation,collapse,or lateral movement by
providing over-the-top and frame ties to
ground anchors.Specific requirements shall
be that:
(i)over-the-top ties be provided at
each of the four corners of the
mobile home,with two additional
ties per side at intermediate loca-
tions,with mobile homes less than
50 feet long requiring one additional
tie per side;
(ii)Frame ties be provided at each corner
of the home with five additional ties
per side at intermediate points,with
mobile homes less than 50 feet long
requiring four additional ties per
side;
(iii)all components of 'the anchoring system
be capable of carrying a force of
4,800 pounds;and
(iv)any additions to the mobile home be
similarly anchored.
(3)An alternative method of anchoring may involve
a system designed to withstand a wind force
of 90 miles per hour or greater.Certifica-
tion must be provideq to the Building Official
that this standard has been met.
B .."Construction Materials_~nd Methods.
(1)All new construction and substantial improve-
ments shall be constructed with materials and
utility equipment resistant to flood damage.
Ordinance -12
,.....
(2)All new construction and substantial improve-
mentsshall be constructed using methods and
practices that minimize flood damage.
c.Utilities.
(1)All new and replacement water supply systems
shall be designed to minimize or eliminate
infiltration of flood waters into the system.
(2)New and replacement sanitary sewage systems
shall be designed to minimize or eliminate
infiltration of flood waters into the systems
and discharge from the systems into flood
waters;and
(3)On-site waste disposal systems shall be
located to avoid impairment to them or con-
tamination from them during flooding.
D.Subdivision Proposals.
(1)All subdivision proposals shall be consistent
with the need to minimize flood damage;
(2)All subdivision proposals shall have pUblic
utilities and facilities such as sewer,gas,
electrical,and water systems located and
constructed to minimize flood damage;
(3)All subdivision proposals shall have adequate
drainage provided to reduce exposure to flood
damage;and
(4)Base flood elevation data shall be provided
for subdivlsion proposals and other proposed
development which contain at least 50 lots or
5 acres (whichever is less).
16.32.150 Review of Building Permits.Where elevation
data is not available,applications for building permits shall be
reviewed to assure that proposed construction will be reasonably
safe from flooding.The test of reasonableness is a local judg-
ment and includes use of historical data,high water marks,photo-
graphs of past flooding,etc.,where available.
16.32.160 Specific Standards.In all areas of special
flood hazards where base flood elevation data has been provided as
set forth in Section 16.32.040 .(Basis for Establishing the Areas of
Special Flood Hazard)or Section 16.32.ll0(B).(Use of Other Base Flood
Data)the following provisions are required:
Ordinance .-13
A.Residential Construction.
New construction and substantial improvement of any
residential structure shall have the lowest floor,
including basement,elevated to or above base flood
elevation.
B.Nonresidential Construction.
New construction and substantial improvement of any
commercial,industrial or other nonresidential struc-
ture shall either have the lowest floor,including
basement,elevated to the level of the base flood ele-
vation;or,together with attendant utility and sani-
tary facilities,shall:
(1)be floodproofed so that below the base flood
level the structure is watertight with walls
substantially impermeable to the passage of
water;
(2)have structural components capable of resisting
hydrostatic and hydrodynamic loads and effects
of bouyancy;
(3)be certified by a registered professional engin-
eer or architect that the standards of this sub-
section are satisfied.Such certification shall
be provided to the Building Official as set forth
in Section l6.32.ll0(C)(2).
C.Mobi'le Homes.
(1)Mobile homes shall be anchored in accordance
with Section l6.32.140(A).
(2)For new mobile home parks and mobile home sub-
divisions;for existing mobile home parks and
mobile home -subdivisions;for expansions to
existing mobile home parks and mobile home sub-
divisions where the repair,reconstruction or
improvement of the streets,utilities and pads
equals or exceeds 50 percent of the value of
the streets,utilities and pads before the
repair,reconstruction,or improvement has
commenced;and for mobile homes not placed in
a mobile home park or mobile home subdivision,
require that:
(i)stands or lots are elevated on compacted
fill or on pilings so that the lowest
floor of the mobile home will be at or
above the base flood level;
Ordinance -14
......f .".•,.•
(ii)adequate surface drainage access for a
hauler are provided;and
(iii)in the instance of elevation on pilings
that:
lots are large enough to permit
steps,
piling foundations are placed .in
stable soil no more than ten feet
apart,and
reinforcement is provided for pilings
more than six feet above the ground
level.
(3)No mobile home shall be placed in a floodway,
except in an existing mobile home park or
existing mobile home subdivision.
16.32.170 Encroachments.The cumulative effect of any
proposed development,when combined with all other existing and
anticipated development,shall not increase the water surface ele-
vation of the base flood more than one foot at any point.
/Jj""!E day
Council and APPROVED by the Mayor this
,1984.
THE CITY OF MARYSVILLE
MAYOR
APPROVED AS TO FORM:ATTEST:
By~fJOi/£L
CITY CLERK
Ordinance -15
AFFIDAVIT OF PUBLICATION'
No._
STATE OF WASHINGTON,
County of Snohomish,
55.
_~_~~~__~~__~~_~~~_'?_~~_~-- ,being first duly sworn
on oath deposes and says that he is the,..__~_e_~!,_e.~~p_;y _
of THE MARYSVILLE GLOBE, a weekly newspaper.
That said newspaper is a legal newspaper which has been ap-
proved by order of the Superior Court in Snohomish County
June 18, 1962 in compliance with Chapter 213 of Washington
Laws of 1941, and it is now and has been for more than six
months prior to the date of the publication hereinafter re-
ferred to,published in the English language continually as a
weekly newspaper in Marysville,Snohomish County,Wash-
ington,and it is now and during,all of said time was printed
in an office maintained at the aforesaid place of publication
of said newspaper.That the annexed is a true copy of a
!~_~!~~__~!__gT_~!9_~~~_~_ff-.~~}_~as it was
published in regular issues (and not in supplement form)of
said newspaper once each week for a period of ~~~__ con-
secutive weeks,commencing on the __~?rt(L day of __:e~!,-t._,
19_8.L.,and ending on the __22nd.day of __F.ab._,19_.8.4-
both dates inclusive,and that such newspaper was regularly
distributed to its subscribers during all of said period.That
the full amount of the fee charged for the foregoing publi-
cation is the sum of $y.~~?5?.__,which amount has been
paid in full (\C----'CJ1JLuJ.D~~
Subscribed and sworn to before me this .d..-::J:::)....dt..__
,.p~
NOTICE OF CITY OF MARYSVILLE ORDINANCE __,190 /~
W~;hl~:to~~t~a~::d ~r~f~:~::~0~~18t;9:~~t~\Zct:councll of the City of Marysville,."..1 ..,~~~~~.
AN ORDINANCE OF THE'CITY OF MARYSVILLE REPEALING CHAPTER 16.32
OF THE MARYSVILLE MUNICIPAL CODE AND ENACTING A NEW CHAPTER and for the State of Washington,
RELATING TO FLOOD HAZARD AREAS.:Idlng at Marysville.
Said ordinance consisted of the following sections:
16.32.010 Statement of purpose.
16.32.020 Definitions.
16.32.030 Lands to Which this Chapter Applies.
16.32.040 Basis for Establishing the Areas Of Special Flood Hazard.
16.32.050 Penalties for Noncompliance.
16.32.060 Abrogation and Greater Restrictions.
16.32.070 Interpretation.
16.32.080 warning and Disclaimer of Liabllltv.
16.32.090 Establishment of Development Permit.
16.32.100 Designation of the Building Official.
16.32.110 Duties and Responsibilities of Building Official.
16.32.120 Appeal Board.
16.32.130 Conditions for Variances.
16.32.140 General Standards.
16.32.150 Review of Building Permits.
16.32.160 Specific Standards.
16.32.170 Encroachments.
The full text of said ordinance will be mailed without charge to any person who re-
Quests the same from the City Clerk.
AF"F"IDAVIT OF"PUBLICATION
No._
STATE OF WASHINGTON,
County of Snohomish,
ss.
_~_~~~__~!__~9_~~~_O_~~_~,being first duly sworn
on oath deposes and says that he is the ~_~~!'_e~~_I.::'l _
of THE MARYSVILLE GLOBE,a weekly newspaper.
That said newspaper is a legal newspaper which has been ap-
proved by order of the Superior Court in Snohomish County
June 18, 1962 in compliance with Chapter 213 of Washington
Laws of 1941,and it is now and has been for more than six
.months prior to the date of the publication hereinafter re-
ferred to,published in the English language continually as a
weekly newspaper in Marysville,Snohomish County,Wash-
ington,and it is now and durmg.all of said time was printed
in an office maintained at the aforesaid place of publication
of said newspaper.That the annexed is a true copy of a
}!9~~~~__~!__9T_~~E1_~Q-~_~_l~J}_~as it was
published in regular issues (and not in supplement form)of
said newspaper once each week for a period of ~~~__ con-
secutive weeks,commencing on the __~?Il_(L day of __:E~!'-~_,
19_81L,and ending on the __22o.d day of __F.ab..._,19_.84.
both dates inclusive, and that such newspaper was regularly
distributed to its subscribers during all of said period.That
the full amount of the fee charged for the foregoing publi-
cation is the sum of $y.~~?_O ,which amount has been
paid in fun (\-C n.:ffl-:;----rf!~-W-®&lillt-------~
Subscribed and sworn to before me this 2"'2\..~__
day of ~:~),,1~~~)'youcan near tile Ululll:>nUl
On the j longhouse..I
WaShlngtd'"My son, Tim,thought o~It;'
AN ORO it, carved it out and painted It.
OF THE N his little corner of the pole.",
RELATINC Williamsexplains that the lowq
Said ordl .I .th1632010inonofthe totem po e.IS e '
16:32:020!area"and serves ~wo pnme pU~l
16.32.030 •"The void area IS used many til
16.32.040 I.memorial poles r-for spirits unk]
16.32.050 for the chiefs we don't know abl
16.32.060 I "Th'don't16.32.070 I IS way,you .
16.32.080'somebody out: It's Just like wh(
16.32.090 I run into your family tree and th!i
16.32.100 I spot open And you don't kno~16.32.110 I .,
16.32.120 J..should be there.·1
16.32.130 'C "At the base of the pole,m~
16.32.140 c;was put on that only the Indian~
16.32.150 ~about.It's to help.keep the spJ
16.32.160 5 h h d't b./16.32.170 E t e pole ~so t ey on go
The full tei Mother Earth."
quests the si Williams says the void are-....-..._----~.....,.,-_..__........"",.....---
Notary Public in and for the State of Washington,
Residing at MarySVille.
FLOOD
INSURANCE-~
STUDY
•
CITY OF
MARYSVILLE,
WASHINGTON
SNOHOMISH COUNTY
AUGUST 15, 1983
Federal Emergency Management Agency
COMMUNITY NUMBER·530168
1..0
TABLE OF CONTENTS
INTRODUCTION ••••••.•••••••.••••••.•••..••••••••••.•••••••••••••••
Page
1
1.1
1.2
1.3
Purpose of Study •••.....••••••
Authority and Acknowledgments.
Coordination .••••••••••••..•••
1
1
1
2.0 AREA.STUD lED •••••••...........••••••...•.....••••••••.•.........•2
2.1
2.2
2.3
2.4
Scope of Study ••••••...••••••
Community Description •••.••.•
Principal Flood Problems ••••
Flood Protection Measures •••
2
2
4
5
3.0 ENG INEERING M~THODS ••••••••••••••••••••••••••••.•••••••••••••••••5
3.1
3.2
Hydrologic Analyses ••
Hydraulic Analyses •••
6
10
4.0 FLOOD PLAIN MANAGEMENT APPLICATIONS .•••••••.•••.•.......•••••••••11
4.1
4.2
Flood Boundaries ••••
Floodways •....••••••
11
12
5.0 INSURANCE APPLICATION ••••.......••.•••••••••••.....••••••••••••••13
5.1
5.2
5.3
5.4
Reach
Flood
Flood
Flood
Determinations ••••••
Hazard Factors ••••••
Insurance Zones ••••••••••••
Insurance Rate Map Description ••.
13
13
15
15
6.0
7.0
8.0
OTHER STUD lES ....••••••••••••••••.......••••••••••••••.......••••
LOCATION OF DATA ••••••.•...•••••••••••••••••••••••••••••••••••••.
BIBLIOGRAPHY AND REFERENCES ••••••••••••••••••••••••••••.•••••••••
i
16
17
17
TABLE OF CONTENTS (Cont'd)
Page
FIGURES
Figure 1 -Vicinity Map........ . •. •. . . • . . . . . . . . . . . . . . . . . . . . •. •. • . . • ••• • 3
TABLES
Table 1 -USGS Stream Gage Stations ......•••••••.......•......•••••....7
Table 2 - Summary of Discharges .....••......••••.......•.~••••.........8
Table 3 - Summary of Elevations .........•.....•..........••.•••.••.....9
Table 4 -Flood Insurance Zone Data....................................14
EXHIBITS
Exhibit 1 -Flood Insurance Rate Map Index
Flood Insurance Rate Map
ii
FLOOD INSURANCE STUDY
1~0 INTRODUCTION
1.1 Purpv~e of Study
This Flood Insurance Study investigates the existence and severity
of flood hazards in the City of Marysville,Snohomish County,
Washington,and aids in the administration of the National Flood
Insurance Act of 1968 and the Flood Disaster Protection Act of
1973.This study will be used to convert Marysville to the regular
program of flood insurance by the Federal Emergency Management
Agency.Local and regional planners will use this study in their
efforts to promote sound flood plain management.
In some state~or communities,flood plain management criteria
or regulations may exist that are more restrictive or comprehensive
than those on which these federally supported studies are based.
These criteria take precedence over the minimum Federal criteria
for purposes of regulating development in the flood plain,as
set for~h in the Code of Federal Regulations at 44 CFR,60.3.
In such cases,however,it shall be understood that the State
(or other jurisdictional agency)shall be able to explain these
requirements and criteria.
1.2 Authority and Acknowledgments
The source of authority for this Flood Insurance Study is the
National Flood Insurance Act of 1968,as amended.
The hydrologic and hydraulic analyses for this study were performed
by the U.S.Army Corps of Engineers,Seattle District,for the
Federal Emergency Management Agency,under Inter-Agency Agreement
No.H-07-76,Project Order No.13.This work,which was completed
in November 1981,covered all significant flooding sources affecting
Marysville.
1.3 Coordination
The identification of streams requiring detailed or approximate
study was made at precontract coordination meetings attended
by officials from the study contractor,the Federal Emergency
Management Agency,the Washington State Department of Ecology,
and county and community governments.A meeting was held in
Marysville on December 8,1975,with officials of this city to
inform community officials of the nature and purpose of the flood
insurance study,to solicit map data,and to establish the scope
of the study.Additional coordination on the scope of the study
and study methods was conducted by the study contractor with
community officials and Federal Emergency Management Agency repre-
sentatives throughout the study period.A Federal Emeregency Manage-
ment Agency letter dated June 10,1980,confirmed the methods
to be used for analysis of tidal flooding.
On October 20,1981,this study was reviewed at an intermediate
meeting attended by representatives of the Federal Emergency Manage-
ment Agency,the U.S.Army Corps of Engineers,Snohomish County,
and the City of Marysville.The study was acceptable.
The final coordination meeting was held on December 15,1982,
and was attended by representatives of the Federal Emergency Manage-
ment Agency,the study contractor,and the city.No probiems were
raised at the meeting.
2.0 AREA STUDIED
2.1 Scope of Study
This Flood Insurance Study covers the incorporated area of the
City of Marysville,Snohomish County,Washington.The area of
study is shown on the Vicinity Map (Figure 1).
Flooding from Ebey and Steamboat Sloughs (distributary channels
of Snohomish River)was studied by detailed methods as agreed
upon during ,precontract and subsequent coordination meetings.
Those areas studied by detailed methods were chosen with considera-
tion given to all proposed construction and forecasted development
through 1986.
Approximate analyses were used to study those areas having a low
development potential or minimal flood hazards.The scope and
methods of study were proposed to and agreed upon by the Federal
Emergency Management Agency and the City of Marysville.
2.2 Community Description
Marysville is located in the west-central portion of Snohomish
County in northwestern washington approximately 4 miles north
of Everett,Washington.Transportation facilities include Interstate
Highway 5,old U.S.Highway 99,and the Burlington Northern Railroad.
Marysville was founded by James P.Comeford who came to the area
in 1872.Comeford served as Indian agent to the Tulalip Indian
Reservation and,in 1877,erected a store,hotel,warehouse,and
dock on Ebey Slough to ,be ~ear the logging operations which were
his principal customers.The community was named "Marysville"
at the request of two visiting friends of Comeford who resided
in Marysville,California.Marysville boomed in its early years
2
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2.3
with the establishment of timber and shake mills located close
to the forestlands and to water and rail transportation routes.
with the clearing of nearby timberland,the land was gradually
turned over to dairying and to the raising of crops such as straw-
berries,raspberries,blueberries,and corn.Today Marysville
is primarily a residential area for people working in Everett
and a distribution point for the surrounding farm and dairy land.
The city also contains timber and wood product mills and a boat
factory (Reference 1).According to washington State Office of
Financial Management figures,the estimated population of Marys-
ville was 5,830 on April 1,1980 (Reference 2).-
Located on the northwestern edge of the low-lying Snohomish River
delta,elevations within Marysville range from sea level along
Ebey and Steamboat Sloughs in the southern part of the city to
approximately 45 feet in the northern part of the city (Reference 3).
Underlying Marysville are fine sandy loam soils.Most of the
land within the city limits of Marysville is either cleared or
vegetated with grass or brush.In a few areas there are mixed
deciduous species such as alder,cottonwood,and maple.Along
Ebey and Steamboat Sloughs are cattails,sedges,rushes,grasses,
and brush.
Development in the flood plain of Marysville consists of residen-
tial,industrial,commercial,and farm structures (Reference 4).
Maritime air influences both precipitation and temperatures in
Marysville,producing a mild,wet climate.The nearest weather
station from which information can be obtained is located near
Everett,approximately 4 miles south of Marysville.This station
is representative of the area and has an average monthly temperature
range from 390F in January to 620F in July..An average of 35
inches of precipitation falls annually,of which 50 percent falls
OCtober through January and 75 percent falls October through April.
Average annual snowfall is 11 inches (Reference 5).Ebeyand
Steamboat Sloughs,distributary channels of the Snohomish River
to the south of Marysville,represent the major flooding sources
of the community.
Principal Flood Problems
Tidal flooding can occur when a high astronomical tide (gravita-
tional effects of the sun and moon)is heightened by a large storm
surge (rise in water levels due to wind stress and low atmospheric
pressure).Wave runup is a significant factor when occurring
during high tide conditions in areas where the shorelines are
not sheltered from local wind effects.
Major floods on rivers and streams in Snohomish County are caused
by rainstorms between OCtober and March.Though floodwaters are
primarily from rainfall,they are often augmented by snowmelt.
4
Snowmelt floods in spring and summer months are usually not as
severe.Rain runoff floods in the study basins are characterized
by sharply rising riverflows with high magnitude peaks and flood
durations ranging a few hours on small streams to several days
on larger rivers.The greatest threat from flooding occurs between
late November and early February when moLsture-laden storms pass
through the Puget Sound region.Characteristically,these storms
are 24 hours in duration with moderate and fairly constant precipita-
tion seldom exceeding I inch per hour.Not uncommon are two or
more storms in rapid succession,sometimes less than 24 hours
apart.
Flooding conditions in Marysville are aggravated if high tidal
levels on Possession Sound occur simultaneously with high flows
.on Ebey and Steamboat Sloughs.The estimated 100-yea~flood will
inundate the following:timber mills located on the right bank
of Ebey Slough in the southwestern part of the city;80 acres
of undeveloped land in the southwestern part of the city;and
120 acres of developed agricultural land in the southeastern part
of the city.
2.4 Flood Protection Measures
Marysville is complying with the emergency phase of the National
Flood Insurance Program by using building permits to regulate
flood plain development in accordance with the best available
flood plain information.
Nine diking districts maintain approximately 42 miles of levees
along the Snohomish River and its three distributary channels,
Ebey Slough,Steamboat Slough,and Union Slough.
Levees exist in Marysville along portions of the left and right
banks of Ebey Slough and along the western city limits south of
Ebey Slough;however,the levees will not protect the city from
a 100-year tidal or Snohomish River flood.
3.0 ENGINEERING METHODS
For the flooding sources studied in detail in the community,standard
hydrologic and hydraulic study methods were used to determine the flood
hazard data required for this study.Flood events of a magnitude which
are expected to be equalled or exceeded once on the average during any
10-,50-,100-,or SOO-year period (recu~ce interval)have been selected
as having special significance for flood plain management and for flood
insurance premium rates.These events,commonly termed the 10-,50-,
100-,and SOO-year floods,have a 10,2,1,and 0.2 percent chance,
respectively,of being equalled or exceeded during any year.Although
the recurrence interval represents the long term average period between
floods of a specific magnitude,rare floods could occur at short intervals
5
or even within the same year.The risk of experiencing a rare flood
increases when periods greater than 1 year are considered.For example,
the risk of having a flood which equals or exceeds the 100-year flood
(1 percent chance of annual occurrence)in any 50-year period is approxi-
mately 40 percent (4 in 10),and,for any 90-year period,the risk increases
to approximately 60 percent (6 in 10).The analyses reported here reflect
flooding potentials based on conditions existing in the community at
the time of completion of this study.Maps and flQod elevations will
be amended periodically to reflect future changes.
3.1 Hydrologic Analyses
Hydrologic analyses were carried out to establish the peak dis-
charge-frequency relationships for floods of the selected recur-
rence intervals for each flooding source studied in detail affect-
ing the community.
Discharge records were published by the u.s.Geological Survey
for the stations listed in Table 1 and were analyzed statistically
following the procedure described by the u.s.Water Resources
Council Bulletin 17A (Reference 6).Statistical analyses were
conducted to determine discharge frequency relationships of the
specified recurrence intervals for each stream studied in detail
in the county.Floodflows at ungaged locations were derived from
disch?rge frequency relationships by adjusting for drainage area,
rainfall intensity,and significant retention areas.
Peak discharge-drainage area relationships for Snohomish River
are shown in Table 2.
Short-term tide records are available at eight locations in Snoho-
mish County,but the nearest long-term record is at Seattle.
The Seattle stage-frequency curve was used to determine the 10-
and 100-year tide stages at each of the short-term stations by
adding the Seattle difference between mean high water (MHW)and
the selected recurrence interval to the MHW at each short-term
station.
A review of tsunami studies and data indicated that tsunamis are
not a significant factor in coastal flooding of Snohomish County.
Elevations for·floods of the selected recurrence intervals on
Ebey and Steamboat Sloughs (distributary channels of Snohomish
River)are shown in Table 3.
Coastal areas of Snohomish County are also subject to tidal flood-
ing.An approximate analysis of tidal flooding was conducted
for the coastal areas of Snohomish County to determine tidal flooding
stages for 10-and 100-year recurrence intervals and a wave runup
factor for use in exposed reaches.The use of these methods was
confirmed by the Federal Emergency Management Agency in a letter
dated June 10,1980.
6
-...I
Name
Snohomish River
Table 1.
Streamgage Stations Operated by USGS and Period of Record Analyzed:
Location
At Snohomish (1555)
Near Monroe (1508)
"
Period of Record
1942-65
1964-75
1930-63,
1976 (computed)
Table 2. Summary of Discharges
Flooding Source and Location
Drainage Area
(Square Miles)
Peak Discharges (Cubic Feet per Second)
10-Year 50-Year 100-Year SOO-Year
co
Snohomish River
At Snohomish
Near Monroe
1,729
1,537
125,000
120,000
141,000
170,000
174,000
192,000
~
243,000
248,000
Table 3.Summary of Elevations
Flooding Source and Location IO-Y'ear
Elevation (Feet)
50-Year IOO-Year SOO-Year
\0
Snohomish Ri ver
(Ebey and Steamboat Sloughs)7.7 8.2 8.4 8.8
3.2 Hydraulic Analyses
Analyses of the hydraulic characteristics of the flooding sources
studied in the community were carried out to provide estimates
of the elevations of floods of the selected recurrence intervals
along each of these flooding sources.
No detailed wave runup analysis was conducted for Snohomish County
coastal areas,but previous studies indicate an average wave runup
of 1.5 feet for moderately exposed reaches in northern Puget Sound.
The Snohomish County shoreline was divided into either exposed
or sheltered reaches,and 1.5 feet was added to the 100-year tidal
stage for the exposed reaches.In sheltered reaches,no runup
factor was added.The methods used for tidal flooding were approved
by the Federal Emergency Management Agency in a letter dated June
10,1982.
Flood elevations for the Snohomish River were calculated using
the multiple junction unsteady flow model that simulates complex
unsteady flow conditions using a hydraulic routing procedure based
on the St.Venant equations,the basic differential equations
of unsteady flow.The program requires time-dependent input of
stage or discharge at the outer model boundaries to calculate
the resultant stage,discharge,and velocity hydrographs at the
interior computational nodes.
For flood profile calculations,channel and overbank roughness
factors (Manning's "n")were initially based on empirical methods,
then adjusted as necessary during model calibration.Field inspec-
tions and photographs aided the "nil value determination.Rough-
ness values for all flooding sources varied from 0.020 to 0.067
for the channel and from 0.040 to 0.150 for the overbank areas.
At Marysville,Snohomish River flooding is all tidal with a con-
stant elevation;therefore,no profiles are presented for this
stream segment.
Numerical models for the rivers studied in detail were calibrated
to the following conditions:
Snohomish River reach from R.M.0.0 to 20.5 - 93 percent
of the observed water-surface elevations of the December
4,1975,flood (126,000 cfs at mouth;20-year recurrence
interval)were reproduced within approximately 0.8 foot.
Snohomish River starting water-surface elevations were based
on a mean higher high tide elevation of 5.0 feet.
Topographic maps were developed by the u.s.Army Corps of Engi-
neers from aerial photographs (Reference 7).The maps were lnl-
tially plotted in manuscript form at a scale of 1:2,400 and a
10
contour interval of 5 feet,and were subsequently redrawn to a
scale of 1:4,800 (Reference 8).All channel cross sections were
field surveyed,and most overbank sections were dev~loped photogram-
metrically and taken between 1971 and 1980.All bridges were
field checked to obtain elevation data and structural geometry.
River mile stationing shown on drawings and tables in this report
was established by interpolating between key landmarks,such as
bridges,for which river mile stationing is specified in the river
mile index (References 9 and 10).Because of channel changes
since the index was established,the published distances between
index stations do not always scale out on the maps.In such cases,
the measured flow line distances between crosS sections were used
in the backwater computations rather than the stationing distances.
Geometric data for each bridge and other hydraulic structures
were included in the backwater models,and the type of flow and
the associated head loss at each structure was computed,but no
additional obstructions were considered.The flood elevations
shown in this study are considered valid only if the hydraulic
structures remain unobstructed,operate properly,and do not fail.
Terrain features,such as roads,railroads,fills,levees,etc.,
which would have a hydraulic effect were considered by selecting
the cross section locations to include and reflect the controlling
effects of such features.No allowances were made in the backwater
models for possible sedimentation,aggradation,erosion,or channel
changes that might have occurred since the cross section surveys
or that might occur in the future.
The rivers that were studied by approximate methods required some
field study.Flood plain boundaries were taken from the published
Flood Hazard Boundary Maps (References 11 and 12)and revised
when necessary after field examination and conversations with
local residents.
All elevations are referenced to the National Geodetic Vertical
Datum of 1929 (NGVD).Elevation reference marks used in the study
are shown on the maps.
4.0 FLOOD PLAIN MANAGEMENT APPLICATIONS
The National Flood Insurance Program encoura~es State and local govern-
ments to adopt sound flood plain management programs.Therefore,each
Flood Insurance Study includes a flood boundary map designed to assist
communities in developing sound flood plain management measures.
4.1 Flood Boundaries
In order to provide a national standard without regional discrimi-
hation,the 100-year flood has been adopted by the Federal Emer-
11
gency Management Agency as the base flood for purposes of flood
plain management measures.The SOD-year flood is employed to
indicate additional areas·of flood risk in the community.For
each stream studied in detail,the boundaries of the 100-and
SOD-year floods have been delineated using the flood elevations
determined at each cross section;between cross sections,the
boundaries were interpolated using topographic maps at a scale
of 1:4,800,with a contour interyal of S feet (Reference 8).
Flood boundaries are indicated on the Flood Insurance Rate Map
(Exhibit 1).On this map,the 100-year flood boundary corresponds
.to the boundary of the areas of special flood hazards .(Zone AI) ;
and the SOD-year flood boundary corresponds to the boundary of
the areas of moderate flood hazards (Zone B).In cases where
the 100-and SOD-year flood boundaries are close together,only
the lOO-year flood boundary has been shown.Small areas within
the flood boundaries may lie.above the flood elevations and,there-
fore,not be subject to flooding;owing to ~imitations of the
map scale;such areas are not shown.
Tidal flooding boundaries in unleveed areas were derived from
inundation maps published in the Coastal Zone Atlas of washington
(Reference 13),which were based on field observations following
an extremely high tide in December 1977.
4.2 Floodways
The floodway is the channel of a stream plus any adjacent flood
plain areas that must be kept free of encroachment in order that
the lOO-year flood may be carried without substantial increases
in flood heights.
The Snohomish River (Ebey and Steamboat Sloughs)floodway was
selected by the Snohomish County Planning Commission with assis-
tance from the technical staff of Everett and Marysville,after
considering a.number of alternative floodway configurations origi-
nally investigated by the u.S.Army Corps of Engineers,Seattle
District,in April 1975 (Reference 14).The U.S.Army Corps of
Engineers tested four floodways,whose boundaries were arbitrary,
for compliance with Federal Emergency Management Agency requirements
(i.e.,1.0 foot surcharge or less).These floodways were presented
to the local governments for review,and a composite was accepted.
This floodway was used for the Everett Flood Insurance Study in
OCtober 1977.Minor revisions were made in accordance with a
request by Snohomish County in their letter of April 17,1979.
This final floodway was.tested for surcharge,but was deleted
from the study at Snohomish County's request at the coordination
meeting of OCtober 20,1981.Snohomish County withdrew the floodway
when anticipated changes to the State Flood Control Zone Act were
not made.Snohomish County committed to regulate the.lower Snohomish
Valley by other methods tnat do not require a floodway.The Commun-
ity Coordination Officer directed that the floodway be deleted.
12
5.0 INSURANCE APPLICATION
In order to establish actuarial insurance rates,the Federal Emergency
Management Agency has developed a process to transform the data from
the engineering study into flood insurance criteria.This process includes
the determination of reaches,Flood Hazard Factors (FHFs),and flood
insurance zone designations for each flooding source studied in detail
affecting Marysville.
5.1 Reach Determinations
Reaches are defined as lengths of watercourses having relatively
the same flood hazard,based on the average weighted difference
in water-surface elevations between the 10-and 100-year floods.
This difference does not have a variation greater than that indi-
cated in the following table for more than 20 percent of the reach:
Average Difference Between
10-and 100-Year Floods
Less than 2 feet
2 to 7 feet
7.1 to 12 feet
More than 12 feet
Variation
0.5 foot
1.0 foot
2.0 feet
3.0 feet
In tidal areas,reaches are limited to the distance for which
the 100-year stillwater flood elevations do not vary more than
1 foot.
The locations of the reaches determined for the flooding sources
of Marysville are shown on the Flood Profiles (Exhibit 1)and
summarized in Table 4.
5.2 Flood Hazard Factors
The FHF is the Federal Emergency Management Agency device used
to correlate flood information with insurance rate tables.Corre-
lations between property damage from floods and their FHF are
used to set actuarial insurance premium rate tables based on FHFs
from 005 to 200.
The FHF for a reach is the average weighted difference between
the 10-and 100-year flood water-surface elevations expressed
to the nearest one-half foot,and shown as a three-digit code.
For example,if the difference between water-surface elevations
of the 10-and 100-year floods is 0.7 foot,the FHF is 005;if
the difference is 1.4 feet,the FHF is 015;if the difference
is 5.0 feet,the FHF is 050.When the difference between the
10-and 100-year water-surface elevations is greater than 10.0
feet,accuracy for the FHF is to the nearest foot.
13
2IELEVATIONDIFFERENCE
I I
BASE FLOOD1BETWEEN1%(lOO-YEAR)FLOOD AND FLOOD
FLOODING SOURCE I PANEL HAZARD ZONE ELEVATION 3
10%2%0.2%FACTOR (FEET NGVD)
(lO-YEAR)(50-YEAR)(SaO-YEAR)
I I
Snohomish River
(Ebey Slough and
Steamboat Slough)
Reach 1 I 0001 I -0.55 I -0.25 I 0.62 I 005 I Al I 9
1 Flood Insurance Rate Map Panel 2weighted Average 3 Rounded to Nearest Foot
~::..
Il:laI
~
,."
•
FEDERAL EMERGENCY MANAGEMENT AGENCY
CITY OF MARYSVILLE,WA
(SNOHOMISH CO.)
,-
FLOOD INSURANCE ZONE DATA
SNOHOMISH RIVER (EBEY SLOUGH AND STEAMBOAT SLOUGH)-,
5.3 Flood Insurance Zones
After the determination of reaches and their respective FHFs,
the entire incorporated area of Marysville was divided into zones,
each having a specific flood potential or hazard.Each zone was
assigned one of the following flood insurance zone designations:
Zone A:
Zone AI:
Zone B:
Zone c:
Special Flood Hazard Areas inundated
by the 100-year flood,determined by
approximate methods;no base flood
elevations shown or FHFs determined.
Special Flood Hazard Areas inundated
by the 100-year flood,determined by
detailed methods;base flood elevations
shown,and zones subdivided according
to FHFs.
Areas between the Special Flood Hazard
Areas and the limits of the SOD-year
flood,including areas of the SOD-year
flood plain that are protected from
the 100-year flood by dike,levee,
or other water control structure;also
areas subject to certain types of 100-
year shallow flooding where depths
are less than 1.0 foot;and areas subject
to lOO-year flooding from sources with
drainage areas less than 1 square mile.
Zona B is not subdivided.
Areas of minimal flooding.
The flood elevation differences,FHFs,'flood insurance zones,
and base flood elevations for each flooding source studied in
detail in the community are summarized in Table 4.
5.4 Flood Insurance Rate Map Description
The Flood Insurance Rate Map for Marysville is,for insurance
purposes,the principal result of the Flood Insurance Study.
This map contains the officiai delineation of flood insurance
zones and base flood elevation lines.Base flood elevation lines
show the locations of the expected whole-foot water-surface eleva-
tions of the base (IOO-year)flood.This map is developed in
accordance with the latest flood insurance map preparation guide-
lines published by the Federal Emergency Management Agency.
15
6.0 OTHER STUDIES
The U.S.Army Corps of Engineers,Seattle District,has published sever-
al reports and studies in Snohomish County including:Flood Plain Infor-
mation,Snohomish River Basin,Washington (References 15 and 16);Snohomish
River Suggested Hydraulic Floodway (Reference 17);and Reconnaissance
Report on Mediated Plan,Snohomish River Basin (Reference 18).The
Pacific Northwest River Basins Commission published Resource Management
Program Main Report,Snohomish River Basin,in June 1981 (Reference 19).
The City of Everett Flood Insurance Study (Reference 20)dated October
1977 is affected by this study in that water-surface profiles shown
in the City of Everett study are significantly lower than presently
calculated..The differences in stage are primarily due to revised hydro-
logic analyses as described below.
The Snohomic'h River discharge frequency relationship for the City of
Everett Flood Insurance Study (Reference 20) was based on a statistical
analysis of 23 years of record (1942-1965)at the gage,"Snohomish River
at Snohomish."In 1973,when the analysis was completed,it was believed
that this record represented existing Snohomish River conditions;but
the December 1975 flood indicated a discrepancy between the Monroe and
Snohomish gage readings.Further analyses of the 1975 flood and other
floods led to the conclusion that levee construction after the 1959
floods had increased the bankfull capacity upstream from the Snohomish
gage from approximately 60,000 cfs to approxiniately 125,000 cfs.The
higher levees .restrict overflow into the Marshland and French Creek
areas,which reduces the attenuating effect of valley storage,leading
to higher peak discharges.Because the Snohomish gage record does not
reflect present overflow conditions,it was decided to use the gage
record at Monroe,which is upstream from the Snohomish gage and not
as affected by the changed valley storage conditions downstream.A
discharge-frequency curve was developed for the Monroe gage by a statistical
analysis of both observed (1964 and on)and computed (1930-1963)peak
discharges.The frequency statistics were adjusted for historical peak
discharges occurring in 1897, 1906, 1918,and 1921 to increase the effective
period of the data base to over 80 years.
The discharge frequencies at Snohomish were determined by routing hypo-
thetical floods from Monroe using an unsteady flow·model to reflect
the changed flood plain conditions.As the result of this analysis,
the 100-year flood discharge at Everett increased from 144,000 cfs to
170,000 cfs,which resulted in a stage increase from 17.7 to 20.0 feet.
Although the increase is primarily due to the changed flow conditions,
some of the increase is probably due to the extended base period developed
for the Monroe gage.
A Flood Insurance Study was prepared for the unincorporated areas of
Snohomish County,Washington (Reference 21).The results of this study
agree with the county study.
This study supersedes the previously published Flood Hazard Boundary
Map for the City of Marysville (Reference 11).
16
,.
This study is authoritative for the purposes of the National Flood Insur-
ance Program;data presented herein either supersede or are compatible
with all previous determinations.
7.0 LOCATION OF DATA
Information concerning the pertinent data used in preparation of this
study can be obtained by contacting the Natural and Technological Hazards
Division,Federal Emergency Management Agency,Federal Regional Center,
130 228th Street,SW.,Bothell,washington 98011.
8.0 BIBLIOGRAPHY AND REFERENCES
1.Everett Daily Herald,"Marysville Owes Early Existence to Logging
Along Snohomish River Delta and Comeford's Trading Post,"August
25,1961
2.Washington State Office of Financial Management,Official April 1,
1980,Population of the Cities,Towns,and Counties,State of
Washington,June 23,1980
3.U.S.Department of Agriculture,Soil Conservation Service,"Prelim-
inary Work Maps of the Soil Survey of Snohomish County (Resurvey),"
1981
4.Flood Control Technical Committee,Puget Sound Task Force of the
Pacific Northwest River Basins Commission,Comprehensive Study
of Water and Related Land Resources:Puget Sound and Adjacent
Waters,State of Washington,Appendix XII,Flood Control,March
1970
5.Cooperative Extension Service,College of Agriculture,Washington
State University,Washington Climate for these Counties:Clallam,
Jefferson Island,San Juan,Skagit,Snohomish,and Whatcom,April
1966
6.u.S.Water Resources Council,"Guidelines for Determining Flood
Flow Frequencies",Bulletin l7A,March 1976
7.U.S.Department of the Army,Corps of Engineers,Seattle District,
Aerial Photographs,flown at 6,000 feet,April 30,1973
8 U.S.Department of the Army,Corps of Engineers,Seattle District,
Topographic Maps,Scale 1:2,400,Contour Interval 5 feet,redrawn
to 1:4,800:Marysville,Washington,1973
9.Hydrology and HydraUliCS Committee of the Pacific Northwest River
Basins Commission,River Mile Index:Stillaguamish River,Skagit
River,Sarnish River,Nooksack River~Puget Sound Basin~British
Columbia,Washington,April 1968
17
10.Hydrology and Hydraulics Committee of the Pacific Northwest River
Basins Commission,River Mile Index:Deschutes River,Nisqually
River,Puyallup River,Green River,Lake Washington,Snohomish
River;Puget Sound Basin,Washington,May 1969
11.u.s.Department of Housing and Urban Development,Federal Insurance
Administration,Flood Hazard Boundary Map,City of Marysville,
Snohomish County,Washington,Scale 1:9,600,1974,Revised 1976
12.u.s.Department of Housing and Urban Development,Federal Insurance
Administration,Flood Hazard Boundary Map,Snohomish County,Washing-
ton (Unincorporated Areas),Scale 1:24,000,1977
13.State of Washington,Department of Ecology,Coastal Zone Atlas
of Washington,Volume 5,Snohomish County,May 1979
14.U.S.Department of the Army,Corps of Engineers,Seattle District,
Special Study,Suggested Hydraulic Floodways,Snohomish River -
Vicinity of Snohomish to Everett,Snohomish County,Washington,
April 1975
15.U.S.Department of the Army,Corps of Engineers,Seattle District,
Flood Plain Information Study,Snohomish River Basin,Washington,
June 1966
16.U.S.Department of the Army,Corps of Engineers,Seattle District,
Flood Plain Information Study,Snohomish River Basin,washington,
May 1967
17.U.S.Department of the Army,Corps of Engineers,Seattle District,
Snohomish River Suggested Hydraulic Floodway,April 1975
18.U.S.Department of the Army,Corps of Engineers,Seattle District,
Reconnaissance Report on Mediated Plan,Snohomish River Basin,
November 1976
19.Pacific Northwest River Basins Commission,Snohomish Study Team,
Resource Management Program Main Report,Snohomish River Basin,
June 1981
20.U.S.Department of Housing and Urban Development,Federal Insurance
Administration,Flood Insurance Study,City of Everett,Snohomish
County,Washington,October 1977
21.Federal Emergency Management Agency,Flood Insurance Study,Snoho-
mish Count¥,Washington (Unincorporated Areas),unpublished
18