02.11.2021CouncilPacket
Ammon City Council
February11,2021
MayorColettiandCityCouncilmembers:
ApprovalofUpdatedFloodplainOrdinance
StaffPresenting:
Tracy Bono, City Engineer/Public Works Director
Recommendation
-StaffrecommendsapprovingtheUpdatedFloodplainOrdinance
SummaryofAnalysis
1.Requirement from IDWR and FEMA to update our ordinance to meet minimum National Flood
InsuranceProgramrequirements.
Financial Impact
1.No financial impact
Motion
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Attachments:
2135 South Ammon Rd., Ammon, Idaho 83406City Hall: (208) 612-4000
www.ci.ammon.id.us Page|1
ORDINANCE NO. 657
CITY OF AMMON
ANORDINANCEOFTHECITYOFAMMON,OFTHESTATEOFIDAHO,
REPEALINGANDREPLACINGTITLE7,CHAPTER10,FLOODPLAIN
REQUIREMENTS,TOALIGNAMMONMUNICIPALCODEWITH
FEDERALFLOODPLAINDEVELOPMENTSTANDARDS;PROVIDINGA
SEVERABILITYCLAUSE;PROVIDINGAREPEALERCLAUSE;AND
PROVIDING AN EFFECTIVE DATE.
WHEREAS, the City of Ammon has heretofore adopted ordinance number 191 and an
amending ordinance number 216, and a further amending ordinance number 232 providing for the
floodplain requirements within the City of Ammon, Bonneville County, Idaho; and
WHEREAS, subsequent amendments to the floodplain requirements have been made to align the
Ammon City Ordinance with the Federal floodplain development requirements; and
WHEREAS, the most recent amendment to the federal floodplain requirements was by Ordinance
608, which revised requirements to further align the Ammon City Ordinance with Federal requirements; and
WHEREAS, Ordinance 657 repeals and replaces previous versions of the floodplain requirements to
fully and comprehensively align the Ammon City Ordinance with the Federal requirements; and
WHEREAS, said previous ordinances have been codified, and the current ordinance will be codified,
within the Codified Ordinances of the City of Ammon as Chapter 10 Title 7.
NOW, THEREFORE, be it hereby ordained by the Mayor and City Council of the City of Ammon that
Ordinance 657 is adopted as follows:
Section1.Title10,Chapter10,FloodPlainRequirementsisherebyrepealedandreplacedwithExhibitA
to this ordinance and retitle Floodplain Requirements.
Section 2. Repeal of Conflicting Provisions.
All provisions of the current Code or ordinances of the City of Ammon which conflict with
the provisions of this ordinance are hereby repealed to the extent of such conflict.
Section 3. Severability.
This ordinance is hereby declared to be severable. Should any portion of this ordinance be
declared invalid by a court of competent jurisdiction, the remaining provisions shall continue
in full force and effect and shall be read to carry out the purpose(s) of the ordinance before
the declaration of partial invalidity.
Section 4. Effective Date.
This ordinance entitled Ordinance No. 657 shall be effective upon its passage and
publication as provided by law.
Enacted by the City Council as Ordinance No. 657 an ordinance of the City of Ammon on the 11 day
of February, 2021.
Approved by the Mayor on the 11 day of February, 2021.
CITY OF AMMON
ORDINANCE 657 AND SUMMARY, UPDATE TO FLOODPLAIN REQUIREMENTS, FEBRUARY 2021
__________________________________
Sean Coletti, Mayor
ATTEST:
_______________________________
Kristina Buchan, City Clerk
ORDINANCE 657 AND SUMMARY, UPDATE TO FLOODPLAIN REQUIREMENTS, FEBRUARY 2021
EXHIBIT A
FLOODPLAIN REQUIREMENTS
ORDINANCE 657 AND SUMMARY, UPDATE TO FLOODPLAIN REQUIREMENTS, FEBRUARY 2021
CHAPTER 10
FLOODPLAIN REQUIREMENTS
7-10-1: Statement of Purpose
7-10-2: Definitions
7-10-3: General Provisions
7-10-4: Administration
7-10-5: Provisions for Flood Hazard Protection
7-10-6: Minimum Flood Proof Basement Design
7-10-7: Accessory Structures
7-10-8: Flood Insurance Study
STATUTORY AUTHORITY:
The Legislature of the State of Idaho, pursuant to Idaho Code §§ 46-1020, 46-1023, and 46-1024,
authorizes local governments to adopt floodplain management ordinances that identify floodplains
and minimum floodplain development standards to minimize flood hazards and protect human life,
health, and property. Therefore, the Council of the City of Ammon, Idaho does hereby ordain as
follows:
7-10-1: STATEMENT OF PURPOSE:
(A) The purpose of this ordinance is to promote public health, safety, and general welfare and to
minimize public and private losses due to flood conditions in specific areas by provisions designed
to:
1.Protect human life, health, and property;
2.Minimizedamagetopublicfacilitiesandutilitiessuchaswaterpurificationand
sewagetreatmentplants,waterandgasmains,electric,telephoneandsewerlines,
streets, and bridges located in floodplains;
3.Helpmaintainastabletaxbasebyprovidingforthesounduseanddevelopmentof
flood prone areas;
4.Minimize expenditure of public money for costly flood control projects;
5.Minimizetheneedforrescueandemergencyservicesassociatedwithflooding,
generally undertaken at the expense of the general public;
6.Minimize prolonged business interruptions;
7.Ensurepotentialbuyersarenotifiedthepropertyisinanareaofspecialfloodhazard;
and
8.Ensurethosewhooccupytheareasofspecialfloodhazardassumeresponsibilityfor
their actions.
(B) Findings of Fact
1. The flood hazard areas of the City of Ammon are subject to periodic inundation which results in
loss of life and property, health and safety hazards, disruption of commerce and governmental
services, extraordinary public expenditures for flood protection and relief, and impairment of the
tax base, all of which adversely affect the public health, safety, and general welfare.
2. These flood losses are caused by development in flood hazard areas, which are inadequately
elevated, flood-proofed, or otherwise unprotected from flood damages, and by the cumulative effect
of obstructions in areas of special flood hazards which increase flood heights and velocities, and
when inadequately anchored, damage uses in other areas. Uses that are inadequately floodproofed,
elevated, or otherwise protected from flood damage also contribute to the flood loss.
3.Localgovernmentunitshavetheprimaryresponsibilityforplanning,adopting,andenforcing
land use regulations to accomplish proper floodplain management.
(C).Objectives and Methods of Reducing Flood Losses
ORDINANCE 657 AND SUMMARY, UPDATE TO FLOODPLAIN REQUIREMENTS, FEBRUARY 2021
In order to accomplish its purpose, this ordinance includes methods and provisions to:
1.Requirethatdevelopmentwhichisvulnerabletofloods,includingstructuresandfacilities
necessaryforthegeneralhealth,safety,andwelfareofcitizens,beprotectedagainstflooddamage
at the time of initial construction;
2.Restrictorprohibitdevelopmentwhicharedangeroustohealth,safety,andpropertyduetowater
or erosion hazards, or which increase flood heights, velocities, or erosion;
3.Controlfilling,grading,dredging,andotherdevelopmentwhichmayincreaseflooddamageor
erosion;
4.Preventorregulatetheconstructionoffloodbarriersthatwillunnaturallydivertfloodwatersor
that may increase flood hazards to other lands;
5.Preserveandrestorenaturalfloodplains,streamchannels,andnaturalprotectivebarrierswhich
carry and store flood waters.
7-10-2: 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 it’s most reasonable application.
ACCESSORY AND AGRICULTURAL STRUCTURES (APPURTENANT STRUCTURE): a
structure on the same lot or parcel as a principal structure, the use of which is incidental and
subordinate to the principal structure.
ADDITION(TOANEXISTINGBUILDING):anextensionorincreaseinthefloorareaorheight
of a building or structure.
AGRICULTURALSTRUCTURES(APPURTENANTSTRUCTURE):astructurewhichisused
exclusivelyinconnectionwiththeproduction,harvesting,storage,raising,ordryingofagricultural
commodities and livestock; specifically excludes any structures used for human habitation.
APPEAL: A request for a review of the City of Ammon’s interpretation of any provision of this
chapter or a request for a variance.
AREA OF SHALLOW FLOODING: 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.
AO is characterized as sheet flow and AH indicates ponding.
AREA OF SPECIAL FLOOD HAZARD: The land in the floodplain within a community subject
to
a one percent or greater chance of flooding in any given year. Designation on maps always includes
the letters A or V.
BASE FLOOD: The flood having a one percent (1%) chance of being equaled or exceeded in any
given year. Also referred to as the “100-year flood.” Designation on maps always includes the
letters A or V.
BASEFLOODELEVATION(BFE):adeterminationbytheFederalInsuranceAdministratorofthe
watersurfaceelevationsofthebaseflood,thatis,thefloodlevelthathasaonepercentorgreater
chanceofoccurrenceinanygivenyear.WhentheBFEhasnotbeenprovidedinaSpecialFlood
HazardArea,itmaybeobtainedfromengineeringstudiesavailablefromaFederal,State,orother
sourceusingFEMA-approvedengineeringmethodologies.Thiselevation,whencombinedwiththe
Freeboard, establishes the Flood Protection Elevation.
BASEMENT: any area of the building having its floor sub grade (below ground level) on all sides.
BUILDING: see Structure.
CLEANING(IRRIGATION):mowing,cutting,orburningofweeds,treesandothernuisance
growth,includingalgaegrowth,applicationofpesticidesaspermitted,removalofbeaverdams,and
removaloftrashorotherdebriswhetherfloating,lodgedorotherwiseobstructingtheconveyance
of water flow through channels and works.
ORDINANCE 657 AND SUMMARY, UPDATE TO FLOODPLAIN REQUIREMENTS, FEBRUARY 2021
CRITICALFACILITIES:facilitiesthatarevitaltofloodresponseactivitiesorcriticaltothehealth
andsafetyofthepublicbefore,during,andafteraflood,suchasahospital,emergencyoperations
center,electricsubstation,policestation,firestation,nursinghome,school,vehicleandequipment
storagefacility,orshelter;andfacilitiesthat,ifflooded,wouldmakethefloodproblemandits
impactsmuchworse,suchasahazardousmaterialsfacility,powergenerationfacility,waterutility,
or wastewater treatment plant.
DATUM:theverticaldatumisabasemeasurementpoint(orsetofpoints)fromwhichall
elevationsaredetermined.Historically,thatcommonsetofpointswastheNationalGeodetic
VerticalDatumof1929(NGVD29).Theverticaldatumcurrentlyadoptedbythefederal
governmentasabasisformeasuringheightsistheNorthAmericanVerticalDatumof1988
(NAVD88)
DEVELOPMENT: 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.
DEVELOPMENT ACTIVITY: any activity defined as Development which will necessitate a
Floodplain Development Permit; such as: the construction of buildings, structures, or accessory
structures; additions or substantial improvements to existing structures; bulkheads, retaining walls,
piers, and pools; the placement of mobile homes; or the deposition or extraction of materials; the
construction or elevation of dikes, berms and levees.
DIGITALFLOODINSURANCERATEMAP(DFIRM):thedigitalofficialmapofacommunity,
issuedbytheFederalInsuranceAdministrator,onwhichboththeSpecialFloodHazardAreasand
the risk premium zones applicable to the community are delineated.
ELEVATEDBUILDING:forinsurancepurposes,anon-basementbuildingwhichhasitslowest
elevatedfloorraisedabovegroundlevelbyfoundationwalls,shearwalls,posts,piers,pilings,or
columns.
ELEVATIONCERTIFICATE:TheElevationCertificateisanimportantadministrativetoolofthe
NFIP.Itisusedtodeterminetheproperfloodinsurancepremiumrate;itisusedtodocument
elevationinformation;anditmaybeusedtosupportarequestforaLetterofMapAmendment
(LOMA) or Letter of Map Revision based on fill (LOMR-F).
ENCLOSURE:anareaenclosedbysolidwallsbelowtheBFE/FPEoranareaformedwhenany
spacebelowtheBFE/FPEisenclosedonallsidesbywallsorpartitions.Insectscreeningoropen
wood lattice used to surround space below the BFE/RFPE is not considered an enclosure.
ENCROACHMENT:theadvanceorinfringementofuses,fill,excavation,buildings,structures,or
development into a floodplain, which may impede or alter the flow capacity of a floodplain.
EXISTINGCONSTRUCTION:forthepurposesofdeterminingrates,structuresforwhichthe
“startofconstruction”commencedbeforetheeffectivedateoftheFIRMorbeforeJanuary1,1975,
forFIRMseffectivebeforethatdate.“Existingconstruction”mayalsobereferredtoas“existing
structures.”
EXISTINGMANUFACTUREDHOMEPARKORMANUFACTUREDHOMESUBDIVISION:
amanufacturedhomeparkorsubdivisionwheretheconstructionoffacilitiesforservicingthelots
onwhichthemanufacturedhomesaretobeaffixed(including,ataminimum,theinstallationof
utilities,theconstructionofstreets,andfinalsitegradingorthepouringofconcretepads)is
completedbeforetheeffectivedateoftheoriginalfloodplainmanagementregulationsadoptedby
the community, July 15, 1982.
EXISTING STRUCTURES: see existing construction.
EXPANSIONTOANEXISTINGMANUFACTUREDHOMEPARKORSUBDIVISION:the
preparationofadditionalsitesbytheconstructionoffacilitiesforservicingthelotsonwhichthe
manufacturinghomesaretobeaffixed(includingtheinstallationofutilities,theconstructionof
streets, and either final site grading or the pouring of concrete pads).
ORDINANCE 657 AND SUMMARY, UPDATE TO FLOODPLAIN REQUIREMENTS, FEBRUARY 2021
FLOOD or FLOODING: (a) 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 approximately caused by flooding as defined in paragraph a.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.
(b) 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 a.1. of this definition.
FLOODBOUNDARYANDFLOODWAYMAP(FBFM):TheFBFMshowshowthefloodplainis
dividedintothefloodwayandfloodfringewherestreamsarestudiedindetail.Theyalsoshow
generalfloodplainareaswherefloodplainshavebeenstudiedbyapproximatemethods.(Oldformat
Pre 1986)
FLOOD ELEVATION DETERMINATION: See Base Flood Elevation (BFE)
FLOOD ELEVATION STUDY: See Flood Insurance Study (FIS)
FLOODHAZARDBOUNDARYMAP(FHBM):anofficialmapofacommunity,issuedbythe
FederalInsuranceAdministrator,wheretheboundariesoftheflood,mudslide(i.e.,mudflow)
related erosion areas having special hazards have been designated as Zones A, M, and/or E.
FLOOD INSURANCE RATE MAP (FIRM): The official map on which the Federal Insurance
Administration has delineated both the areas of special flood hazards and the risk premium zones
applicable to the community.
FLOOD INSURANCE STUDY: 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.
FLOODZONE:ageographicalareashownonaFloodHazardBoundaryMap(FHBM)orFlood
InsuranceRateMap(FIRM)thatreflectstheseverityortypeoffloodinginthearea,andapplicable
insurance rate.
FLOODPLAINORFLOOD-PRONEAREA:anylandareasusceptibletobeinginundatedbywater
from any source (see definition of “flooding”).
FLOODPLAINADMINISTRATOR:theindividualappointedtoadministerandenforcethe
floodplain management regulations.
FLOODPLAIN DEVELOPMENT PERMIT: any type of permit that is required in conformance
with the provisions of this ordinance, prior to the commencement of any development activity.
FLOODPLAINMANAGEMENT:theoperationofanoverallprogramofcorrectiveandpreventive
measuresforreducingflooddamage,includingbutnotlimitedtoemergencypreparednessplans,
flood control works, and floodplain management regulations.
FLOODPLAINMANAGEMENTREGULATIONS:zoningordinances,subdivisionregulations,
buildingcodes,healthregulations,specialpurposeordinances(suchasafloodplainordinance,
gradingordinance,anderosioncontrolordinance),andotherapplicationsofpolicepower.Theterm
describessuchstateorlocalregulations,inanycombinationthereof,whichprovidestandardsfor
the purpose of flood damage prevention and reduction.
FLOODPROOFING:anycombinationofstructuralandnon-structuraladditions,changes,or
adjustmentstostructureswhichreduceoreliminateflooddamagetorealestateorimprovedreal
property, water and sanitary facilities, structures and their contents.
ORDINANCE 657 AND SUMMARY, UPDATE TO FLOODPLAIN REQUIREMENTS, FEBRUARY 2021
FLOOD PROTECTION ELEVATION (FPE): the Base Flood Elevation plus the Freeboard.
•In“SpecialFloodHazardAreas”whereBaseFloodElevations(BFEs)havebeen
determined, this elevation shall be the BFE plus 2 feet of freeboard; and
•In“SpecialFloodHazardAreas”wherenoBFEhasbeenestablished,thiselevationshallbe
at least 2 feet above the highest adjacent grade.
FLOODPROTECTIONSYSTEM:thosephysicalstructuralworksforwhichfundshavebeen
authorized,appropriated,andexpendedandwhichhavebeenconstructedspecificallytomodify
floodinginordertoreducetheextentoftheareawithinacommunitysubjecttoa“specialflood
hazard”andtheextentofthedepthsofassociatedflooding.Suchasystemtypicallyincludesdams,
reservoirs,levees,ordikes.Thesespecializedfloodmodifyingworksarethoseconstructedin
conformance with sound engineering standards.
FLOODWAY: 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.
FREEBOARD:afactorofsafetyusuallyexpressedinfeetaboveafloodlevelforthepurposesof
floodplainmanagement.Freeboardtendstocompensateforthemanyunknownfactorsthatcould
contributetofloodheightsgreaterthantheheightcalculatedforaselectedsizefloodandfloodway
conditions,suchaswaveaction,obstructedbridgeopenings,debrisandicejams,andthe
hydrologiceffectsofurbanizationinawatershed.TheBaseFloodElevation(BFE)plusthe
freeboard establishes the Flood Protection Elevation (FPE). Freeboard shall be 2 feet.
FUNCTIONALLYDEPENDENTUSE:afacilitythatcannotbeusedforitsintendedpurpose
unlessitislocatedorcarriedoutincloseproximitytowater,suchasadockingorportfacility
necessaryfortheloadingandunloadingofcargoorpassengers,shipbuilding,orshiprepair
facilities. The term does not include long-term storage, manufacture, sales, or service facilities.
GENERALIRRIGATIONFLOODPLAINDEVELOPMENTPERMIT(GIFDPERMIT):The
intentoftheGIFDpermitistocollectivelyauthorizelow-to-noimpactirrigationanddrainage
developmentactivitiesorusesinthefloodplainwhichinherentlydonotincreasetheBFE.GIFD
permitsapplytoallqualifyingactivitieswithinthespatialextentsofanirrigationdeliveryor
drainagesystemandwithintheregulatoryfloodwayorSFHA,overapredeterminedperiodoftime,
nottoexceedfiveyears.IssuanceofaGIFDpermitrequirescoordinationbetweentheirrigation
entity and the Floodplain Administrator.
HIGHESTADJACENTGRADE(HAG):thehighestnaturalelevationofthegroundsurfaceprior
toconstruction,adjacenttotheproposedwallsofastructure.RefertotheFEMAElevation
Certificate for HAG related to building elevation information.
HISTORIC STRUCTURE: a structure that is:
a.ListedindividuallyintheNationalRegisterofHistoricPlaces(alistingmaintainedbytheU.S.
DepartmentofInterior)orpreliminarilydeterminedbytheSecretaryoftheInteriorasmeeting
the requirements for individual listing on the National Register;
b.CertifiedorpreliminarilydeterminedbytheSecretaryoftheInteriorascontributingtothe
historicalsignificanceofaregisteredhistoricdistrictortoadistrictpreliminarilydeterminedby
the Secretary to qualify as a registered historic district;
c.Individuallylistedonastateinventoryofhistoricplacesanddeterminedaseligiblebystates
withhistoricpreservationprogramswhichhavebeenapprovedbytheSecretaryoftheInterior;
or
d.Individuallylistedonalocalinventoryofhistoricplacesanddeterminedaseligibleby
communities with historic preservation programs that have been certified either:
1.by an approved state program as determined by the Secretary of the Interior, or
2.directly by the Secretary of the Interior in states without approved programs.
LETTEROFMAPCHANGE(LOMC):ageneraltermusedtorefertotheseveraltypesof
revisionsandamendmentstoFIRMsthatcanbeaccomplishedbyletter.TheyincludeLetterof
MapAmendment(LOMA),LetterofMapRevision(LOMR),andLetterofMapRevisionbasedon
Fill (LOMR-F)
•LETTEROFMAPAMENDMENT(LOMA):anofficialamendment,byletter,toaneffective
NationalFloodInsuranceProgram(NFIP)map.ALOMAestablishesaproperty’sorstructure’s
ORDINANCE 657 AND SUMMARY, UPDATE TO FLOODPLAIN REQUIREMENTS, FEBRUARY 2021
locationinrelationtotheSpecialFloodHazardArea(SFHA).LOMAsareusuallyissued
becauseapropertyorstructurehasbeeninadvertentlymappedasbeinginthefloodplainbutis
actually on natural high ground above the base flood elevation.
•LETTEROFMAPREVISION(LOMR):FEMA'smodificationtoaneffectiveFloodInsurance
RateMap(FIRM)oraFloodBoundaryandFloodwayMap(FBFM)orboth.LOMRsare
generallybasedontheimplementationofphysicalmeasuresthataffectthehydrologicor
hydrauliccharacteristicsofafloodingsourceandthusresultinthemodificationoftheexisting
regulatoryfloodway,theeffectiveBaseFloodElevations(BFEs),ortheSpecialFloodHazard
Area(SFHA).TheLOMRofficiallyrevisestheFloodInsuranceRateMap(FIRM)orFlood
BoundaryandFloodwayMap(FBFM),andsometimestheFloodInsuranceStudy(FIS)report,
andwhenappropriate,includesadescriptionofthemodifications.TheLOMRisgenerally
accompanied by an annotated copy of the affected portions of the FIRM, FBFM, or FIS report.
•LETTEROFMAPREVISIONBASEDONFILL(LOMR-F):FEMA'smodificationofthe
SpecialFloodHazardArea(SFHA)shownontheFloodInsuranceRateMap(FIRM)basedon
theplacementoffilloutsidetheexistingregulatoryfloodway.TheLOMR-Fdoesnotchange
the FIRM, FBFM, or FIS report.
•CONDITIONALLETTEROFMAPREVISION(CLOMR):Aformalreviewandcommentas
towhetheraproposedfloodprotectionprojectorotherprojectcomplieswiththeminimum
NFIPrequirementsforsuchprojectswithrespecttodelineationofspecialfloodhazardareas.A
CLOMRdoesnotrevisetheeffectiveFloodInsuranceRateMap(FIRM)orFloodInsurance
Study(FIS).Uponsubmissionandapprovalofcertifiedas-builtdocumentation,aLetterofMap
Revision(LOMR)maybeissuedbyFEMAtorevisetheeffectiveFIRM.BuildingPermits
and/orFloodDevelopmentPermitscannotbeissuedbasedonaCLOMR,becauseaCLOMR
does not change the NFIP map.
LEVEE:aman-madestructure,usuallyanearthenembankment,designedandconstructed
accordingtosoundengineeringpractices,tocontain,control,ordiverttheflowofwatersoasto
provide protection from temporary flooding.
LEVEESYSTEM:afloodprotectionsystemthatconsistsofalevee,orlevees,andassociated
structures,suchasclosureanddrainagedevices,whichareconstructedandoperatedinaccordance
with sound engineering practices.
LOWESTADJACENTGRADE(LAG):thelowestpointofthegroundlevelnexttothestructure.
Refer to the FEMA Elevation Certificate for LAG related to building elevation information.
LOWEST FLOOR: The lowest floor of the lowest enclosed area (including basement). An
unfinished or flood resistance 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 at Section 7-10-5 (B)
1(b).
MAINTENANCE(IRRIGATION):theactofongoingupkeepofexistingstructuresrequiredto
keepchannelsinaconditionadequatetosupporttheconveyanceofirrigationanddrainagewater
(thisdoesnotincludethecompletereplacementorsubstantialreplacementofanexistingstructure).
Maintenanceisfurtherdefinedasthecareorupkeepofchannels,works,appurtenances,easements,
utilitycorridorsandproperty;tokeepinanexistingstate,specifiedstateofrepair,andefficiency;
returntoaformercondition,elevation,place,andposition;topreservefromfailureordecline;or
repairorrenovatesoastoreturnittoitsoriginalcondition.Maintenancedoesnotincludedredging
as defined herein.
MANUFACTURED HOME: 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 connected
to the required utilities. For floodplain management purposes the term “manufactured home” also
includes park trailers, travel trailers, and other similar vehicles placed on a site for greater than 180
consecutive days. For insurance purposes the term “manufactured home” does not include park
trailers, travel trailers, and other similar vehicles.
MANUFACTURED HOME PARK OR SUBDIVISION: A parcel (or contiguous parcels) of land
divided into two (2) or more manufactured home lots for rent or sale.
ORDINANCE 657 AND SUMMARY, UPDATE TO FLOODPLAIN REQUIREMENTS, FEBRUARY 2021
MARKETVALUE:thebuildingvalue,notincludingthelandvalueandthatofanyaccessory
structuresorotherimprovementsonthelot.Marketvaluemaybeestablishedbyindependent
certifiedappraisal;replacementcostdepreciatedforageofbuildingandqualityofconstruction
(Actual Cash Value); or adjusted tax assessed values.
MEANSEALEVEL:forpurposesoftheNationalFloodInsuranceProgram(NFIP),theNational
GeodeticVerticalDatum(NGVD)of1929orotherdatum(suchasNorthAmericaVerticalDatum
of1988-NAVD88)towhichBaseFloodElevations(BFEs)shownonacommunity’sFIRMare
referenced.
MUDSLIDE(I.E.,MUDFLOW):describesaconditionwherethereisariver,flow,orinundation
ofliquidmuddownahillsideusuallyasaresultofadualconditionoflossofbrushcoverandthe
subsequentaccumulationofwateronthegroundprecededbyaperiodofunusuallyheavyor
sustainedrain.Amudslide(i.e.,mudflow)mayoccurasadistinctphenomenonwhilealandslideis
inprogress,andwillberecognizedassuchbytheAdministratoronlyifthemudflow,andnotthe
landslide, is the proximate cause of damage that occurs.
MUDSLIDE(I.E.,MUDFLOW)AREAMANAGEMENT:theoperationofanoverallprogramof
correctiveandpreventivemeasuresforreducingmudslide(i.e.,mudflow)damage,includingbut
notlimitedtoemergencypreparednessplans,mudslidecontrolworks,andfloodplainmanagement
regulations.
MUDSLIDE(I.E.,MUDFLOW)PRONEAREA:anareawithlandsurfacesandslopesof
unconsolidated material where the history, geology, and climate indicate a potential for mudflow.
NATIONALFLOODINSURANCEPROGRAM(NFIP):TheNFIPisaFederalprogramcreated
byCongresstomitigatefuturefloodlossesnationwidethroughsound,community-enforced
buildingandzoningordinancesandtoprovideaccesstoaffordable,federallybackedflood
insurance protection for property owners.
NEW CONSTRUCTION: Structures for which the “start of construction” commenced on or after
the effective date of this chapter. Any construction started after July 15, 1982 and before the
effective start date of this floodplain management ordinance is subject to the ordinance in effect at
the time the permit was issued, provided the start of construction was within 180 days of permit
issuance.
RECREATIONAL VEHICLE: a vehicle that is:
a.Built on a single chassis, and
b.400 square feet or less when measured at the largest horizontal projection, and
c.Designed to be self-propelled or permanently towed by a light duty truck, and
d.Designedprimarilynotforuseasapermanentdwellingbutastemporarylivingquartersfor
recreational, camping, travel, or seasonal use.
REGULATORY FLOODWAY: See Floodway
REMEDYAVIOLATION:tobringthestructureorotherdevelopmentintocompliancewithState
orlocalfloodplainmanagementregulations,or,ifthisisnotpossible,toreducetheimpactsofits
non-compliance.Waysthatimpactsmaybereducedincludeprotectingthestructureorother
affecteddevelopmentfromflooddamages,implementingtheenforcementprovisionsofthe
ordinanceorotherwisedeterringfuturesimilarviolations,orreducingFederalfinancialexposure
with regard to the structure or other development.
REPAIR(IRRIGATION):therestorationtogoodorsoundconditionsofanypartofanexisting
structure,channel,channelbank,orserviceroadforthepurposeofmaintenance(thisdoesnot
includethecompletereplacementorsubstantialreplacementofanexistingstructure).Repairdoes
not include dredging as defined herein.
REPETITIVELOSSSTRUCTURE:AnNFIP-insuredstructurethathashadatleasttwopaidflood
losses of more than $1,000 each in any 10-year period since 1978.
RIVERINE: relating to, formed by, or resembling a river (including tributaries), stream, brook, etc.
ORDINANCE 657 AND SUMMARY, UPDATE TO FLOODPLAIN REQUIREMENTS, FEBRUARY 2021
SPECIALFLOODHAZARDAREA(SFHA):thelandinthefloodplainwithinacommunity
subjecttoaonepercent(1%)orgreaterchanceoffloodinginanygivenyear.Forpurposesofthese
regulations,theterm“specialfloodhazardarea”issynonymousinmeaningwiththephrase“areaof
special flood hazard”
START OF CONSTRUCTION: Includes substantial improvement and means the date the building
permit was issued, provided the actual start of construction, repair, reconstruction, placement, or
other improvement was within 180 days of the permit date. The actual start means either the first
placement of permanent construction of a structure on a site, such as the pouring of slabs 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, footing,
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 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.
STRUCTURE: A walled and roofed building, including a gas or liquid storage tank that is
principally above ground,as well as a manufactured home.
SUBSTANTIAL DAMAGE: 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 (50%) of
its market value before the damage occurred. See definition of “substantial improvement”
SUBSTANTIAL IMPROVEMENT: Any repair, reconstruction, or improvement of a structure, the
cost of which equals or exceeds fifty percent (50%) 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:
•Anyprojectforimprovementofastructuretocorrectexistingviolationsofstateorlocal
health,sanitary,orsafetycodespecificationswhichhavebeenidentifiedbythelocalcode
enforcementofficialandwhicharetheminimumnecessarytoassuresafelivingconditions;
or
•Anyalterationofa“historicstructure”,providedthatthealterationwillnotprecludethe
structure'scontinueddesignationasa“historicstructure”andthealterationisapprovedby
variance issued pursuant to this ordinance
TECHNICALBULLETINSANDTECHNICALFACTSHEETS:FEMApublicationsthatprovide
guidanceconcerningthebuildingperformancestandardsoftheNFIP,whicharecontainedinTitle
44oftheUSCodeofFederalRegulations§60.3.Thebulletinsandfactsheetsareintendedforuse
primarilybyStateandlocalofficialsresponsibleforinterpretingandenforcingNFIPregulations
andbymembersofthedevelopmentcommunity,suchasdesignprofessionalsandbuilders.New
bulletins,aswellasupdatesofexistingbulletins,areissuedperiodicallyasneeded.Thebulletinsdo
notcreateregulations.Rathertheyprovidespecificguidanceforcomplyingwiththeminimum
requirements of existing NFIP regulations.
ItshouldbenotedthatTechnicalBulletinsandTechnicalFactSheetsprovideguidanceonthe
minimumrequirementsoftheNFIPregulations.Stateorcommunityrequirementsthatexceedthose
oftheNFIPtakeprecedence.Designprofessionalsshouldcontactthecommunityofficialsto
determinewhethermorerestrictiveStateorlocalregulationsapplytothebuildingorsitein
question.AllapplicablestandardsoftheStateorlocalbuildingcodemustalsobemetforany
building in a flood hazard area.
TEMPERATURECONTROLLED:havingthetemperatureregulatedbyaheatingand/orcooling
system, built-in or appliance.
VARIANCE: A grant of relief from the requirements of this chapter which permits construction in
a manner that would otherwise be prohibited by this chapter.
ORDINANCE 657 AND SUMMARY, UPDATE TO FLOODPLAIN REQUIREMENTS, FEBRUARY 2021
VIOLATION: the failure of a structure or other development to be fully compliant with the
community's floodplain management regulations. A structure or other development without the
Finished Construction Elevation Certificate, other certifications, or other evidence of compliance
required in 44 CFR § 60.3(b)(5), (c)(4), (c)(10), (d)(3), (e)(2), (e)(4), or (e)(5) is presumed to be in
violation until such time as that documentation is provided.
WATERSURFACEELEVATION:theheight,inrelationtotheNationalGeodeticVerticalDatum
(NGVD)of1929ortheNorthAmericanVerticalDatum(NAVD)of1988(orotherspecified
datum),offloodsofvariousmagnitudesandfrequenciesinthefloodplainsofcoastalorriverine
areas.
WATERCOURSE: a lake, river, creek, stream, wash, channel, or other topographic feature on or
over which waters flow at least periodically. Watercourse includes specifically designated areas in
which substantial flood damage may occur.
7-10-3: GENERAL PROVISIONS:
(A) Lands to Which This Chapter Applies: This chapter shall apply to all areas of special
flood hazards within the jurisdiction of the City of Ammon. Nothing in this ordinance is
intended to allow uses or structures that are otherwise prohibited by the zoning ordinance.
(B) 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 engineering
report entitled “The Ammon Flood Insurance Study and Maps for Ammon, Idaho,” dated
July 19, 1982, with accompanying Flood Insurance Rate Maps (FIRM) is hereby adopted by
this reference and declared to be a part of this chapter. The Flood Insurance Study is on file
at City Hall, City of Ammon, 2135 South Ammon Road, Idaho 83406.
(C) Penalties for Noncompliance: No structure of land shall hereafter be constructed,
located, extended, converted, 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 violation of conditions and
safeguards established in connection with conditions) shall constitute a misdemeanor.
Any person who violates this ordinance or fails to comply with any of its requirements
shall upon conviction thereof be fined not more than Three Hundred Dollars ($300) or
imprisoned for not more than ninety (90) days, or both, for each violation, and in addition
shall pay all costs and expenses involved in the case. Nothing herein contained shall prevent
the City of Ammon from taking such other lawful action as is necessary to
prevent or remedy any violation.
(D) Abrogation and Greater Restrictions: This chapter is not intended to repeal, abrogate, or
impair any existing easements, covenants, or deed restrictions. However, where this chapter
and another chapter, ordinance, easement, covenant, or deed restriction conflict or overlap,
whichever imposes the more stringent restrictions shall prevail.
(E) 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; and
3. Deemed neither to limit nor repeal any other powers granted under state
statutes.
(F) Warning and Disclaimer of Liability: The degree of flood protection required by this
chapter is considered reasonable for regulatory purposes and is based on scientific 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 Ammon, any officer or employee thereof, or the Federal Insurance
ORDINANCE 657 AND SUMMARY, UPDATE TO FLOODPLAIN REQUIREMENTS, FEBRUARY 2021
Administration for any flood damages that result from reliance on this chapter or any
administrative decision lawfully made hereunder.
7-10-4: ADMINISTRATION
(A) 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 7-10-3-(B) above. The permit shall be for all structures including manufactured
homes, as set forth in Section 7-10-2, Definitions, and for all other development including
fill and other activities, also as set forth in Section 7-10-2, Definitions.
(B) Designation of the Local Administrator: The City of Ammon City Engineer is hereby
appointed to administer and implement this chapter by granting or denying development
permit applications in accordance with its provisions.
(C) Duties and Responsibilities of the Local Administrator: Duties of the City Engineer
shall include, but not be limited to:
1. Permit Review:
(a) Review all development permits to determine that the permit requirements of
this chapter have been satisfied.
(b) Review all development permits to determine that all necessary permits have
been obtained from those federal, state, or local governmental agencies from
which prior approval is required.
(c) Review all development permits to determine if the proposed development is
located in the floodway. If located in the floodway, assure that the
encroachment provisions of Section 7-10-5(C) 1 are met.
2. Use of Other Flood Data: When base flood elevation and floodway data have not
been provided in accordance with Section 7-10-3(B), Basis for Establishing the Areas
of Special Flood Hazard, the City Engineer shall obtain, review, and reasonably utilize
any base flood elevation and floodway data available from a federal, state, or source, in
order to administer Section 7-10-5(B)1, Specific Standards, Residential Construction,
Section 7-10-5(B)2, Specific Standards,
Nonresidential Construction, and Section 7-10-5(C), Floodways.
3. Information to be Obtained and Maintained:
(a) Where base flood elevation data is provided through the Flood Insurance Study
or required as in Section 7-10-4(C)2, obtain and record the actual elevation (in
relation to mean sea level) of the lowest habitable floor (including basement) of all
new or substantially improved structures, and whether or not the structure contains
a basement.
(b) For all new or substantially improved floodproofed structures:
(1) Verify and record the actual elevation (in relation to mean sea level), and
(2) Maintain the floodproofing certifications required in Section 7-10-5 (B) 3.
(3) Maintain for public inspection all records pertaining to the provisions of
this chapter.
4. Alteration of Watercourses:
(a) Notify adjacent communities and the Idaho Water Resource Board prior to any
alteration or relocation of a water course, and submit evidence of such notification
to the Federal Insurance Administration.
(b) Require that maintenance is provided within the altered or relocated portion of
said water course so that the flood carrying capacity is not diminished.
ORDINANCE 657 AND SUMMARY, UPDATE TO FLOODPLAIN REQUIREMENTS, FEBRUARY 2021
(c). 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 the actual
field conditions). The person contesting the location of the boundary shall be given
a reasonable opportunity to appeal the interpretation. Such appeals shall be granted
consistent with the appeals procedure as provided in Section 7-10-4(D)4 of this
chapter and the standards of Section 1910.6 of the rules and regulations of the
National Flood Insurance Program (24 CFR 1909, etc.)
(d). When floodproofing is utilized for a particular structure, obtain and maintain
certifications from a registered professional engineer or architect in accordance
with the provisions of 7-10-3(b) and 7-10-5 (B)2.
(e).WhenBaseFloodElevation(BFE)dataisprovidedbutnofloodwaydatahas
beenprovidedinaccordancewiththeprovisionsof7-10-3(B)requirethatnonew
construction,substantialimprovements,orotherdevelopment(includingfill)shall
bepermittedwithinZonesAEonthecommunity'sFIRM,unlessitisdemonstrated
thatthecumulativeeffectoftheproposeddevelopment,whencombinedwithall
otherexistingandanticipateddevelopment,willnotincreasethewatersurface
elevationofthebasefloodmorethanonefootatanypointwithinthecommunity.
(This is a Hydraulic & Hydrology Analysis)
(f).Makeon-siteinspectionsofworkinprogress.Astheworkpursuanttoa
floodplaindevelopmentpermitprogresses,theFloodplainAdministratorshall
makeasmanyinspectionsoftheworkasmaybenecessarytoensurethatthework
isbeingdoneaccordingtotheprovisionsofthelocalordinanceandthetermsof
thepermit.Inexercisingthispower,theFloodplainAdministratorhasaright,
uponpresentationofpropercredentials,toenteronanypremiseswithinthe
jurisdictionofthecommunityatanyreasonablehourforthepurposesofinspection
or other enforcement action.
(g).Issuestop-workordersasrequired.Wheneverabuildingorpartthereofis
beingconstructed,reconstructed,altered,orrepairedinviolationofthisordinance,
theFloodplainAdministratormayordertheworktobeimmediatelystopped.The
stop-workordershallbeinwritinganddirectedtothepersondoingorinchargeof
thework.Thestop-workordershallstatethespecificworktobestopped,the
specificreason(s)forthestoppage,andthecondition(s)underwhichtheworkmay
be resumed. Violation of a stop-work order constitutes a misdemeanor.
(h).Revokefloodplaindevelopmentpermitsasrequired.TheFloodplain
Administratormayrevokeandrequirethereturnofthefloodplaindevelopment
permitbynotifyingthepermitholderinwritingstatingthereason(s)forthe
revocation.Permitsshallberevokedforanysubstantialdeparturefromthe
approvedapplication,plans,andspecifications;forrefusalorfailuretocomply
withtherequirementsofStateorlocallaws;orforfalsestatementsor
misrepresentationsmadeinsecuringthepermit.Anyfloodplaindevelopment
permitmistakenlyissuedinviolationofanapplicableStateorlocallawmayalso
be revoked.
(i).MakeperiodicinspectionsthroughouttheSpecialFloodHazardAreaswithin
thejurisdictionofthecommunity.TheFloodplainAdministratorandeach
memberofhisorherinspectionsdepartmentshallhavearight,uponpresentation
ofpropercredentials,toenteronanypremiseswithintheterritorialjurisdictionof
thedepartmentatanyreasonablehourforthepurposesofinspectionorother
enforcement action.
(g. Review, provide input, and make recommendations for variance requests.
(j).Maintainacurrentmaprepositorytoinclude,butnotlimitedto,theFIS
Report,FIRMandotherofficialfloodmaps,andstudiesadoptedinaccordance
withtheprovisionsofArticleIII,SectionBofthisordinance,includingany
revisionstheretoincludingLettersofMapChange,issuedbyFEMA.Notifythe
NFIP State Coordinator and FEMA of your community’s mapping needs.
ORDINANCE 657 AND SUMMARY, UPDATE TO FLOODPLAIN REQUIREMENTS, FEBRUARY 2021
(k).CoordinaterevisionstoFISreportsandFIRMs,includingLettersofMap
Revision Based on Fill (LOMR-Fs) and Letters of Map Revision (LOMRs).
(l).Acommunity'sbasefloodelevationsmayincreaseordecreaseresultingfrom
physicalchangesaffectingfloodingconditions.Assoonaspracticable,butnot
laterthansixmonthsafterthedatesuchinformationbecomesavailable,a
communityshallnotifytheFederalInsuranceAdministrator(FIA)ofthechanges
bysubmittingtechnicalorscientificdatainaccordancewiththispart.Sucha
submissionisnecessarysothatuponconfirmationofthosephysicalchanges
affectingfloodingconditions,riskpremiumratesandfloodplainmanagement
requirements will be based upon current data.
(m).Uponoccurrence,notifytheFederalInsuranceAdministrator(FIA)inwriting
whenevertheboundariesofthecommunityhavebeenmodifiedbyannexationor
thecommunityhasotherwiseassumedornolongerhasauthoritytoadoptand
enforcefloodplainmanagementregulationsforaparticulararea.Inorderthatall
FHBM'sandFIRM'saccuratelyrepresentthecommunity'sboundaries,include
withinsuchnotificationacopyofamapofthecommunitysuitablefor
reproduction,clearlydelineatingthenewcorporatelimitsornewareaforwhich
thecommunityhasassumedorrelinquishedfloodplainmanagementregulatory
authority
(D)Floodplain Development Application, Permit, and Certification Requirements
1.ApplicationRequirements:.ApplicationforaFloodplainDevelopmentPermitshall
bemadetotheFloodplainAdministratorpriortoanydevelopmentactivitieslocated
withinSpecialFloodHazardAreas.Thefollowingitemsshallbepresentedtothe
Floodplain Administrator to apply for a floodplain development permit:
(a).Aplotplandrawntoscalewhichshallinclude,butshallnotbelimitedto,the
following specific details of the proposed floodplain development:
1.thenature,location,dimensions,andelevationsoftheareaof
development/disturbance;existingandproposedstructures,utilitysystems,
grading/pavementareas,fillmaterials,storageareas,drainagefacilities,and
other development;
2.theboundaryoftheSpecialFloodHazardAreaasdelineatedontheFIRM
orotherfloodmapasdeterminedin7-10-3(B),orastatementthattheentire
lot is within the Special Flood Hazard Area;
3.thefloodzone(s)designationoftheproposeddevelopmentareaas
determinedontheFIRMorotherfloodmapasdeterminedinArticleIII,
Section B;
4. the boundary of the floodway(s) as determined in Article III, Section B;
5. the Base Flood Elevation (BFE) where provided as set forth in7-10-3(B)
6.theoldandnewlocationofanywatercoursethatwillbealteredorrelocated
as a result of proposed development; and
(b).Proposedelevation,andmethodthereof,ofalldevelopmentwithinaSpecial
Flood Hazard Area including but not limited to:
1.Elevationinrelationtomeansealeveloftheproposedlowestfloor
(including basement) of all structures;
2.Elevationinrelationtomeansealeveltowhichanynon-residential
structure in Zone A, AE, AH, or AO will be floodproofed; and
3.Elevationinrelationtomeansealeveltowhichanyproposedutility
equipment and machinery will be elevated or floodproofed.
(c).Iffloodproofing,aFloodproofingCertificate(FEMAForm086-0-33)with
supportingdata,anoperationalplan,andaninspectionandmaintenanceplanthat
include,butarenotlimitedto,installation,exercise,andmaintenanceofflood
proofing measures will be required prior to Certificate of Occupancy/Completion.
ORDINANCE 657 AND SUMMARY, UPDATE TO FLOODPLAIN REQUIREMENTS, FEBRUARY 2021
(d).AFoundationPlan,drawntoscale,whichshallincludedetailsoftheproposed
foundationsystemtoensureallprovisionsofthisordinancearemet.Thesedetails
include but are not limited to:
1.Theproposedmethodofelevation,ifapplicable(i.e.,fill,solidfoundation
perimeterwall,solidbackfilledfoundation,openfoundation,oron
columns/posts/piers/piles/shear walls); and
2.Openingstofacilitateautomaticequalizationofhydrostaticfloodforceson
wallsinaccordancewithArticleV,SectionA.8.b.whensolidfoundation
perimeter walls are used in Zones A, AE, AH, and AO.
(e). Usage details of any enclosed areas below the lowest floor.
(f).Plansand/ordetailsfortheprotectionofpublicutilitiesandfacilitiessuchas
sewer,gas,electrical,andwatersystemstobelocatedandconstructedtominimize
flood damage.
(g).CertificationthatallotherLocal,State,andFederalpermitsrequiredpriorto
floodplain development permit issuance have been received.
(h).Documentationforplacementofrecreationalvehiclesand/ortemporary
structures,whenapplicable,toensurethattheprovisionsof7-10-5(B)5&6.ofthis
ordinance are met.
(i).Adescriptionofproposedwatercoursealterationorrelocation,when
applicable,includinganengineeringreportontheeffectsoftheproposedproject
ontheflood-carryingcapacityofthewatercourseandtheeffectstoproperties
located both upstream and downstream; and
1.Amap(ifnotshownonplotplan)showingthelocationoftheproposed
watercourse alteration or relocation.
2.PermitRequirements:TheFloodplainDevelopmentPermitshallinclude,butnotbe
limited to:
(a).Acompletedescriptionofallthedevelopmenttobepermittedunderthe
floodplaindevelopmentpermit(i.e.house,garage,pool,septic,bulkhead,cabana,
polebarn,chickencoop,pier,bridge,mining,dredging,filling,rip-rap,docks,
grading,paving,excavationordrillingoperations,orstorageofequipmentor
materials, etcetera).
(b).TheSpecialFloodHazardAreadeterminationfortheproposeddevelopment
in accordance with available data specified in 7-10-3(B).
(c).TheFloodProtectionElevationrequiredforthelowestfloorandallattendant
utilities.
(d).TheFloodProtectionElevationrequiredfortheprotectionofallutility
equipment and machinery.
(e). All certification submittal requirements with timelines.
(f).Astatementthatnofillmaterialorotherdevelopmentshallencroachintothe
floodway of any watercourse, as applicable.
(g). The flood openings requirements, if in Zones A, AE, AH, or AO.
(h).Allfloodplaindevelopmentpermitsshallbeconditionaluponthestartof
constructionofworkwithin180days.Afloodplaindevelopmentpermitshall
expire180daysafterissuanceunlessthepermittedactivityhascommencedasper
the Start of Construction definition.
(i).Fullyenclosedareasbelowthelowestfloorareusablesolelyforparkingof
vehicles, building access, or storage.
(j). All materials below BFE/FPE must be flood resistant materials.
3. Certification Requirements:
(a).Elevation Certificates
1.AConstructionDrawingsElevationCertificate(FEMAForm86-0-33)is
requiredpriortotheactualstartofanynewconstruction.Itshallbetheduty
ORDINANCE 657 AND SUMMARY, UPDATE TO FLOODPLAIN REQUIREMENTS, FEBRUARY 2021
ofthepermitholdertosubmittotheFloodplainAdministratoracertification
oftheelevationofthelowestfloor,inrelationtomeansealevel.The
FloodplainAdministratorshallreviewthecertificatedatasubmitted.
Deficienciesdetectedbysuchreviewshallbecorrectedbythepermitholder
priortothebeginningofconstruction.Failuretosubmitthecertificationor
failuretomakerequiredcorrectionsshallbecausetodenyafloodplain
development permit.
2.ABuildingUnderConstructionElevationCertificate(FEMAForm
86-0-33)isrequiredafterthelowestfloorisestablished.Withinseven(7)
calendardaysofestablishmentofthelowestfloorelevation,itshallbethe
dutyofthepermitholdertosubmittotheFloodplainAdministratora
certificationoftheelevationofthelowestfloor,inrelationtomeansealevel.
Anyworkdonewithintheseven(7)daycalendarperiodandpriorto
submissionofthecertificationshallbeatthepermitholder’srisk.The
FloodplainAdministratorshallreviewthecertificatedatasubmitted.
Deficienciesdetectedbysuchreviewshallbecorrectedbythepermitholder
immediatelyandpriortofurtherworkbeingpermittedtoproceed.Failureto
submitthecertificationorfailuretomakerequiredcorrectionsshallbecause
to issue a stop-work order for the project.
3.Afinalas-builtFinishedConstructionElevationCertificate(FEMAForm
86-0-33)isrequiredafterconstructioniscompletedandpriortoCertificateof
Compliance/Occupancyissuance.Itshallbethedutyofthepermitholderto
submittotheFloodplainAdministratoracertificationoffinalas-built
constructionoftheelevationofthelowestfloorandallattendantutilities.
TheFloodplainAdministratorshallreviewthecertificatedatasubmitted.
Deficienciesdetectedbysuchreviewshallbecorrectedbythepermitholder
immediatelyandpriortoCertificateofCompliance/Occupancyissuance.In
someinstances,anothercertificationmayberequiredtocertifycorrected
as-builtconstruction.Failuretosubmitthecertificationorfailuretomake
requiredcorrectionsshallbecausetowithholdtheissuanceofaCertificateof
Compliance/Occupancy.
(b).FloodproofingCertificate.Ifnon-residentialfloodproofingisusedtomeetthe
FloodProtectionElevationrequirements,designplans,withsupportingdata,an
operationalplan,andaninspectionandmaintenanceplanarerequiredpriortothe
actualstartofanynewconstruction.Itshallbethedutyofthepermitholderto
submittotheFloodplainAdministratoracertificationofthefloodproofeddesign
elevationofthelowestfloorandallattendantutilities,inrelationtomeansea
level.Floodproofingcertificationshallbepreparedbyorunderthedirect
supervisionofaprofessionalengineerorarchitectandcertifiedbysame.The
FloodplainAdministratorshallreviewthecertificatedata,theoperationalplan,and
theinspectionandmaintenanceplan.Deficienciesdetectedbysuchreviewshall
becorrectedbytheapplicantpriortopermitapproval.Failuretosubmitthe
certificationorfailuretomakerequiredcorrectionsshallbecausetodenya
FloodplainDevelopmentPermit.PriortorequestforaCertificateof
Compliance/OccupancyaFloodproofingCertificate(FEMAForm086-0-34)shall
be provided to the Floodplain Administrator for review and approval.
(c).IfamanufacturedhomeisplacedwithinZoneA,AE,AH,orAOandthe
elevationofthechassisismorethan36inchesinheightabovegrade,an
engineeredfoundationcertificationisrequiredinaccordancewiththeprovisionsof
7-10-5 (B)3(b).
(d).Ifawatercourseistobealteredorrelocated,thefollowingshallallbe
submittedbythepermitapplicantpriortoissuanceofafloodplaindevelopment
permit:
1. a description of the extent of watercourse alteration or relocation; and
ORDINANCE 657 AND SUMMARY, UPDATE TO FLOODPLAIN REQUIREMENTS, FEBRUARY 2021
2.aprofessionalengineer’scertifiedreportontheeffectsoftheproposed
projectontheflood-carryingcapacityofthewatercourseandtheeffectsto
properties located both upstream and downstream; and
3.amapshowingthelocationoftheproposedwatercoursealterationor
relocation; and
4.anIdahoStreamChannelAlterationPermitapprovalshallbeprovidedby
the applicant to the Floodplain Administrator.
(e).CertificationExemptions.Thefollowingstructuresareexemptfromthe
elevation/floodproofingcertificationrequirementsspecifiedinitemsa.andb.of
this subsection:
1. Recreational Vehicles meeting requirements of 7-10-5 (B)5(a);
2. Temporary Structures meeting requirements of 7-10-5 (B)6; and
3.AccessoryStructureslessthan200squarefeetmeetingrequirementsof
7-10-5 (B)7.
(E)DeterminationsforExistingBuildingsandStructures.Forapplicationsforbuilding
permitstoimprovebuildingsandstructures,includingalterations,movement,enlargement,
replacement,repair,changeofoccupancy,additions,rehabilitations,renovations,
improvements,repairsofdamage,andanyotherimprovementoforworkonsuchbuildings
andstructures,theFloodplainAdministrator,incoordinationwiththeBuildingOfficial,
shall:
1.Estimatethemarketvalue,orrequiretheapplicanttoobtainanappraisalofthe
marketvaluepreparedbyaqualifiedindependentappraiser,ofthebuildingor
structurebeforethestartofconstructionoftheproposedwork.Inthecaseofrepair,
themarketvalueofthebuildingorstructureshallbethemarketvaluebeforethe
damage occurred and before any repairs are made;
2.Comparethecosttoperformtheimprovement,thecosttorepairadamaged
buildingtoitspre-damagedcondition,orthecombinedcostsofimprovementsand
repairs, if applicable, to the market value of the building or structure;
3.Determineanddocumentwhethertheproposedworkconstitutessubstantial
improvement or repair of substantial damage; and
4.Notifytheapplicantifitisdeterminedthattheworkconstitutessubstantial
improvementorrepairofsubstantialdamageandthatcompliancewiththeflood
resistantconstructionrequirementsoftheadoptedIdahoBuildingCodeandthis
ordinance is required.
(F). Corrective Procedures
1.ViolationstobeCorrected:WhentheFloodplainAdministratorfindsviolationsof
applicableStateandlocallaws,itshallbehisorherdutytonotifytheowneror
occupantofthebuildingoftheviolation.Theowneroroccupantshallimmediately
remedy each of the violations of law cited in such notification.
2.ActionsinEventofFailuretoTakeCorrectiveAction:Iftheownerofabuildingor
propertyshallfailtotakepromptcorrectiveaction,theFloodplainAdministratorshall
givetheownerwrittennotice,bycertifiedorregisteredmailtotheowner’slastknown
address or by personal service, stating:
(a).thatthebuildingorpropertyisinviolationofthefloodplainmanagement
regulations;
(b).thatahearingwillbeheldbeforetheFloodplainAdministratoratadesignated
placeandtime,notlaterthanten(10)daysafterthedateofthenotice,atwhich
timetheownershallbeentitledtobeheardinpersonorbycounselandtopresent
arguments and evidence pertaining to the matter; and
(c).thatfollowingthehearing,theFloodplainAdministratormayissueanorderto
alter, vacate, or demolish the building; or to remove fill as applicable.
ORDINANCE 657 AND SUMMARY, UPDATE TO FLOODPLAIN REQUIREMENTS, FEBRUARY 2021
3.OrdertoTakeCorrectiveAction.If,uponahearingheldpursuanttothenotice
prescribedabove,theFloodplainAdministratorshallfindthatthebuildingor
developmentisinviolationoftheFloodDamagePreventionOrdinance,heorshe
shallissueanorderinwritingtotheowner,requiringtheownertoremedythe
violationwithinaspecifiedtimeperiod,notlessthansixty(60)calendardays,nor
morethan180calendardays.WheretheFloodplainAdministratorfindsthatthereis
imminentdangertolifeorotherproperty,heorshemayorderthatcorrectiveactionbe
taken in such lesser period as may be feasible.
(a).Appeal:Anyownerwhohasreceivedanordertotakecorrectiveactionmay
appealtheordertothelocalelectedgoverningbodybygivingnoticeofappealin
writingtotheFloodplainAdministratorandtheclerkwithinten(10)days
followingissuanceofthefinalorder.Intheabsenceofanappeal,theorderofthe
FloodplainAdministratorshallbefinal.Thelocalgoverningbodyshallhearan
appealwithinareasonabletimeandmayaffirm,modifyandaffirm,orrevokethe
order.
(b).FailuretoComplywithOrder:Iftheownerofabuildingorpropertyfailsto
complywithanordertotakecorrectiveactionforwhichnoappealhasbeenmade
orfailstocomplywithanorderofthegoverningbodyfollowinganappeal,the
ownershallbeguiltyofamisdemeanorandshallbepunishedatthediscretionof
the court.
4. Variance Procedure:
(a). Appeal Board:
(1) The Board of Adjustment or the City Council acting as the Board
of Adjustment, as established by the City of Ammon, shall hear and
decide appeals and requests for variances from the requirements of this
chapter.
(2) The Board of Adjustment, or the City Council acting as the Board
of Adjustment, shall hear and decide appeals when it is alleged there is
an error in any requirement, decision, or determination made by the
Enforcement Officer in the enforcement or administration of this
chapter.
(3) Those aggrieved by the decision of the Board of Adjustment, or the
City Council acting as the Board of Adjustment, or any taxpayer, may
appeal such decision to the Seventh Judicial District Court, as
provided by Idaho statutes.
(4) In passing upon such applications, the Board of Adjustment, or the
City Council acting as the Board of Adjustment, shall consider all
technical evaluations, all relevant factors, standards specified in other
sections of this chapter, and:
(a) The danger that materials may be swept onto other lands to the
injury of others;
(b) The danger to life and property due to flooding or erosion
damage;
(c) The susceptibility of the proposed facility and its contents to
flood damage and the effect of such damage on the individual
owner;
(d) The importance of the services provided by the proposed
facility to the community;
(e) The necessity to the facility of a waterfront location, where
applicable;
(f) The availability of alternative locations for the proposed use
which are not subject to flooding or erosion damage;
(g) The compatibility of the proposed use with existing and
anticipated development;
ORDINANCE 657 AND SUMMARY, UPDATE TO FLOODPLAIN REQUIREMENTS, FEBRUARY 2021
(h) The relationship of the proposed use to the comprehensive plan
and floodplain management program for that area;
(i) The safety of access to the property in times of flood for
ordinary and emergency vehicles;
(j) The expected heights, velocity, duration, rate of rise, and
sediment transport of the flood waters and the effects of wave
action, if applicable, expected at the site; and
(k) 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, and water
systems, and streets and bridges.
(5) Upon consideration of the factors of Section 7-10-4 (D) 1(d) and the
purposes of this chapter, the Board of Adjustment, or the City Council
acting as the Board of Adjustment, may attach such conditions to the
granting of variances as it deems necessary to further the purposes of
this chapter.
(6) The City Engineer shall maintain the records of all appeal actions
and report any variances to the Federal Insurance Administration upon
request.
(b). Conditions for Variance:
(1) Generally, the only condition under which a variance from the
elevation
standard may be issued is for new construction and substantial
improvements to be erected on a lot of one-half (½) acre or less in size
contiguous to and surrounded by lots with existing structures
constructed below the base flood level, providing items (i-xi) in Section
7-10-4 (D) 1(d) have been fully considered. As the lot size increases the
technical justification required for issuing the variance increases.
(2) Variances may be issued for the reconstruction, 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 this section.
(3) Variances shall not be issued within a designated floodway if any
increase in flood levels during the base flood discharge would result.
(4) Variances shall only be issued upon a determination that the
variance is the minimum necessary, considering the flood hazard, to
afford relief.
(5)functionallydependentfacilities,ifdeterminedtomeetthe
definitionasstatedinArticleIIofthisordinance,providedprovisions
of7-10-4(E)2,havebeensatisfied,andsuchfacilitiesareprotectedby
methodsthatminimizeflooddamagesduringthebasefloodandcreate
no additional threats to public safety; or
(6)anyothertypeofdevelopment,provideditmeetstherequirements
of this Section.
(7) Variances shall only be issued upon:
(a) A showing of good and sufficient cause;
(b) A determination that failure to grant the variance would result in
exceptional hardship to the applicant;
(c) 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.
ORDINANCE 657 AND SUMMARY, UPDATE TO FLOODPLAIN REQUIREMENTS, FEBRUARY 2021
(8) Variances as interpreted in the National Flood Insurance Program
are based on the general zoning law principle that they pertain to a
physical piece of property; they are not personal in nature and do not
pertain to the structure, its inhabitants, economic or financial
circumstances. They primarily address small lots in densely populated
residential neighborhoods. As such, variances from the flood elevations
should be quite rare.
(7) Variances may be issued for nonresidential buildings in very limited
circumstances to allow a lesser degree of floodproofing than watertight
or dry-floodproofing, where it can be determined that such action will
have low damage potential, complies with all other variance criteria
except Section 7-10-4 (D) 2(a), and otherwise complies with Sections
7-10-5 (A) 1 and 7-10-5 (A) 2 of the GENERAL STANDARDS.
(8) Any applicant to whom a variance is granted shall be given written
notice that the structure will be permitted to be built with a lowest floor
elevation below the base flood elevation and that the cost of flood
insurance will be commensurate with the increased risk resulting from
the reduced lowest floor elevation.
7-10-5: PROVISIONS FOR FLOOD HAZARD PROTECTION:
(A) General Standards: In all areas of special flood hazards, the following standards are
required:
1. Anchoring:
(a) All new construction and substantial improvements shall be anchored to
prevent flotation, collapse, or lateral movement of the structure.
(b) All manufactured homes must likewise 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.
(Reference FEMA’s “Manufactured Home Installation in Flood Hazard
Areas” guidebook for additional techniques.)
2. Construction Materials and Methods:
(a) All new construction and substantial improvements shall be constructed
with materials and utility equipment resistant to flood damage in accordance
with the Technical Bulletin 2, Flood Damage-Resistant Materials Requirements,
and available from the Federal Emergency Management Agency.
(b) All new construction and substantial improvements shall be constructed
using methods and practices that minimize flood damage.
(c) Electrical, heating, ventilation, plumbing, and air-conditioning equipment
and other service facilities shall be designed and/or otherwise elevated or
located so as to prevent water from entering or accumulating within the
components during conditions of flooding to the Flood Protection Elevation.
These include, but are not limited to, HVAC equipment, water softener units,
bath/kitchen fixtures, ductwork, electric/gas meter panels/boxes, utility/cable
boxes, hot water heaters, and electric outlets/switches.
3. Utilities:
(a) All new and replacement water supply systems shall be designed to
minimize or eliminate infiltration of flood waters into the system;
ORDINANCE 657 AND SUMMARY, UPDATE TO FLOODPLAIN REQUIREMENTS, FEBRUARY 2021
(b) 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
(c) On-site waste disposal systems shall be located to avoid impairment to them
or contamination from them during flooding.
4. Subdivision Proposals:
(a) All subdivision proposals shall be required to mitigate and remove from the
flood plain prior to any building permits being issued on lots within the
boundaries of the floodplain as they now exist.
(b) All subdivision proposals shall have public utilities and facilities such as
sewer, gas, electrical, and water systems located and constructed to minimize
flood damage;
(c) All subdivision proposals shall have adequate drainage provided to reduce
exposure to flood damage; and
(d) Base flood elevation data shall be provided for subdivision proposals and
other proposed development which contain at least fifty (50) lots or five (5)
acres, whichever is less.
(e) All subdivision proposals and other development proposals shall have
received all necessary permits from those governmental agencies for which
approval is required by Federal or State law, including Section 404 of the
Federal Water Pollution Control Act Amendments of 1972, 33 USC 1334
5. Review of Building Permits: Where elevation data is not available either through
the Flood Insurance Study or from another authoritative source (Section
7-10-4(C)2), 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 judgment and includes use of historical data, high
water marks, photographs of past flooding, etc., where available. Failure to
elevate at least two feet above grade in these zones may result in higher
insurance rates.
6.Nothing in this ordinance shall prevent the repair, reconstruction, or replacement
of a building or structure existing on the effective date of this ordinance and located
totally or partially within the floodway, or stream setback, provided there is no
additional encroachment below the Flood Protection Elevation in the floodway, or
stream setback, and provided that such repair, reconstruction, or replacement meets
all of the other requirements of this ordinance.
(B) Specific Standards: In all areas of special flood hazards where base flood elevation
data
has been provided as set forth in Section 7-10-3(B), Basis for Establishing the Area of
Special Flood Hazard or Section 7-10-4(C)2, use of Other Base Flood Data, the
following provisions are required:
1. Residential Construction:
(a) New construction and substantial improvement of any residential
structure shall have the lowest floor, including basement, elevated to or
ORDINANCE 657 AND SUMMARY, UPDATE TO FLOODPLAIN REQUIREMENTS, FEBRUARY 2021
above base flood elevation, or comply with flood proof basement
requirements as set forth in Section 7-10-6 of this chapter.
(b) Fully enclosed areas below the lowest floor that are subject to flooding are
prohibited, or 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:
(1) A minimum of two openings having a total net area of not less than one
square inch for every square foot of enclosed are 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)Ifabuildinghasmorethanoneenclosedarea,eachenclosedareamust
have flood openings to allow floodwaters to automatically enter and exit;
(5)Enclosuresmadeofflexibleskirtingarenotconsideredenclosuresfor
regulatorypurposes,and,therefore,donotrequirefloodopenings.Masonry
orfloodresistantwoodunderpinning,regardlessofstructuralstatus,is
considered an enclosure and requires flood openings as outlined above.
2. Nonresidential Construction: New construction and substantial improvement of
any commercial, industrial, or other nonresidential structure shall either have the
lowest floor, including basement, elevated to the level of the base flood elevation;
or, together with attendant utility and sanitary facilities, shall:
(a) Be floodproofed so that below the base flood level the structure is
watertight with walls substantially impermeable to the passage of water;
(b) Have structural components capable of resisting hydrostatic and
hydrodynamic loads and effects of buoyancy;
(c) 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 officials as set forth
in Section 7-10-4(C)3(b); and
(d) Nonresidential structures that are elevated, not floodproofed, must meet
the same standards for space below the lowest floor as described in Section
7-10-5 (B) 1(2).
(e) Manufactured Homes: All manufactured homes to be placed or substantially
improved within Zones A1-30, AH, and AE shall be elevated on a permanent
foundation such that the lowest floor of the manufactured home is at or above
the base flood elevation and be securely anchored to an adequately anchored
foundation system in accordance with the provisions of Section 7-10-5 (A) 1(b).
ORDINANCE 657 AND SUMMARY, UPDATE TO FLOODPLAIN REQUIREMENTS, FEBRUARY 2021
(f)Newsolidwastedisposalfacilitiesandsites,hazardouswastemanagement
facilities,salvageyards,andchemicalstoragefacilitiesshallnotbepermitted,
exceptbyvarianceasspecifiedinArticleIV,SectionE.9.Astructureortank
forchemicalorfuelstorageincidentaltoanalloweduseortotheoperationofa
watertreatmentplantorwastewatertreatmentfacilitymaybelocatedina
SpecialFloodHazardAreaonlyifthestructureortankiseitherelevatedor
floodproofedtoatleasttheFloodProtectionElevationandcertifiedin
accordance with the provisions of 7-10-4 (C) 3.
3. Basements:
(a)Bedesignedandbuiltsothatanybasementarea,togetherwithattendant
utilitiesandsanitaryfacilitiesbelowthefloodproofeddesignlevel,iswatertight
withwallsthatareimpermeabletothepassageofwaterwithouthuman
intervention.Basementwallsshallbebuiltwiththecapacitytoresisthydrostatic
andhydrodynamicloadsandtheeffectsofbuoyancyresultingfromfloodingto
thefloodproofeddesignlevel,andshallbedesignedsothatminimaldamage
willoccurfromfloodsthatexceedthatlevel.Thefloodproofeddesignlevel
shallbeanelevationonefootabovethelevelofthebasefloodwherethe
differencebetweenthebasefloodandthe500-yearfloodisthreefeetorless
andtwofeetabovethelevelofthebasefloodwherethedifferenceisgreater
than three feet.
(b)Havethetopofthefloorofanybasementareanolowerthanfivefeetbelow
the elevation of the base flood;
(c)Havetheareasurroundingthestructureonallsidesfilledtoorabovethe
elevationofthebaseflood.Fillmustbecompactedwithslopesprotectedby
vegetative cover;
(d)Havearegisteredprofessionalengineerorarchitectdeveloporreviewthe
building'sstructuraldesign,specifications,andplans,includingconsiderationof
thedepth,velocity,anddurationoffloodingandtypeandpermeabilityofsoils
atthebuildingsite,andcertifythatthebasementdesignandmethodsof
constructionproposedareinaccordancewithacceptedstandardsofpracticefor
meeting the provisions of this paragraph;
(e)Beinspectedbythebuildinginspectororotherauthorizedrepresentativeof
thecommunitytoverifythatthestructureisbuiltaccordingtoitsdesignand
those provisions of this section which are verifiable.
4. Additions/Improvements:
a.Additionsand/orimprovementstopre-FIRMstructureswhentheaddition
and/orimprovementsincombinationwithanyinteriormodificationstothe
existing structure are
1.notasubstantialimprovement,theadditionand/orimprovementsmustbe
designedtominimizeflooddamagesandmustnotbeanymore
non-conforming than the existing structure; or
2.asubstantialimprovement,boththeexistingstructureandtheaddition
and/or improvements must comply with the standards for new construction.
b.Additionstonon-compliantpost-FIRMstructuresthatareasubstantial
improvementwithnomodificationstotheexistingstructureotherthana
standarddoorinthecommonwallshallrequireonlytheadditiontocomplywith
the standards for new construction.
c.Additionsand/orimprovementstonon-compliantpost-FIRMstructureswhen
theadditionand/orimprovementsincombinationwithanyinterior
modifications to the existing structure are
1.notasubstantialimprovement,theadditionand/orimprovementsonly
must comply with the standards for new construction; or
ORDINANCE 657 AND SUMMARY, UPDATE TO FLOODPLAIN REQUIREMENTS, FEBRUARY 2021
2.asubstantialimprovement,boththeexistingstructureandtheaddition
and/or improvements must comply with the standards for new construction.
d.Anycombinationofrepair,reconstruction,rehabilitation,addition,or
improvementofabuildingorstructuretakingplaceduringa10yearperiod,the
cumulativecostofwhichequalsorexceeds50percent(50%)ofthemarket
valueofthestructurebeforetheimprovementorrepairisstarted,mustcomply
withthestandardsfornewconstruction.Foreachbuildingorstructure,the10
yearperiodbeginsonthedateofthefirstimprovementorrepairofthatbuilding
orstructuresubsequenttotheeffectivedateofthisordinance.Ifthestructure
hassustainedsubstantialdamage,anyrepairsareconsideredsubstantial
improvementregardlessoftheactualrepairworkperformed.Therequirement
does not, however, include either:
1.anyprojectforimprovementofabuildingrequiredtocorrectexisting
health,sanitary,orsafetycodeviolationsidentifiedbythebuildingofficial
and that are the minimum necessary to assume safe living conditions; or
2.anyalterationofahistoricstructureprovidedthatthealterationwillnot
preclude the structure’s continued designation as a historic structure.
5. Recreational Vehicles. Recreational vehicles shall be either:
a.Temporary Placement
1.beonsiteforfewerthan180consecutivedaysandbefullylicensedand
readyforhighwayuse(arecreationalvehicleisreadyforhighwayuseifitis
onitswheelsorjackingsystem,isattachedtothesiteonlybyquick
disconnect type utilities, and has no permanently attached additions); or
b.Permanent Placement.
1.Recreationalvehiclesthatdonotmeetthelimitationsof
TemporaryPlacementshallmeetalltherequirementsfornew
construction, as set forth in 7-10-5 (A).
6. Temporary Non-Residential Structures:
Priortotheissuanceofafloodplaindevelopmentpermitforatemporarystructure,
theapplicantmustsubmittotheFloodplainAdministratoraplanfortheremovalof
suchstructure(s)intheeventofaflashfloodorothertypeoffloodwarning
notification.Thefollowinginformationshallbesubmittedinwritingtothe
Floodplain Administrator for review and written approval:
a.aspecifiedtimeperiodforwhichthetemporaryusewillbepermitted.Time
specified may not exceed six (6) months, renewable up to one (1) year;
b.thename,address,andphonenumberoftheindividualresponsibleforthe
removal of the temporary structure;
c.thetimeframepriortotheeventatwhichastructurewillberemoved(i.e.,
immediately upon flood warning notification);
d.acopyofthecontractorothersuitableinstrumentwiththeentityresponsible
for physical removal of the structure; and
e.designation,accompaniedbydocumentation,ofalocationoutsidethe
Special Flood Hazard Area, to which the temporary structure will be moved.
f.TemporarystructuresinthefloodwaymustprovideaHydraulicand
Hydrology Analysis along with a No-Rise Certification.
7. Accessory and Agricultural Structures (Appurtenant structures):
Whenaccessorystructures(sheds,detachedgarages,etc.)usedsolelyforparking,
andstoragearetobeplacedwithinaSpecialFloodHazardArea,elevationor
floodproofingcertificationsarerequiredforallaccessorystructuresinaccordance
with 7-10-4 (D) 3, and the following criteria shall be met:
a.Accessorystructuresshallnotbeusedforhumanhabitation(including
working, sleeping, living, cooking, or restroom areas);
b.Accessory structures shall not be temperature-controlled;
c.Accessory structures shall be designed to have low flood damage potential;
ORDINANCE 657 AND SUMMARY, UPDATE TO FLOODPLAIN REQUIREMENTS, FEBRUARY 2021
d.Accessorystructuresshallbeconstructedandplacedonthebuildingsiteso
as to offer the minimum resistance to the flow of floodwaters;
e.Accessorystructuresshallbefirmlyanchoredinaccordancewiththe
provisions of 7-10-5 (A)1;
f.Allutilityequipmentandmachinery,suchaselectrical,shallbeinstalledin
accordance with the provisions of 7-10-5 (A)2(c); and
g.Floodopeningstofacilitateautomaticequalizationofhydrostaticflood
forcesshallbeprovidedbelowFloodProtectionElevationinconformancewith
the provisions of 7-10-5(B)1(b).
h. Accessorystructuresnotusedsolelyforparking,access,andstoragemustbe
elevated per 7-10-5 (B)1 and 7-10-5 (B)2.
Anaccessorystructurewithafootprintlessthan200squarefeetandisa
minimalinvestmentof$7,500andsatisfiesthecriteriaoutlinedi na-gaboveis
not required to provide the elevation certificate per 7-10-5 (B)2.
8. Tanks:
WhengasandliquidstoragetanksaretobeplacedwithinaSpecialFloodHazard
Area, the following criteria shall be met:
a.Undergroundtanksinfloodhazardareasshallbeanchoredtoprevent
flotation,collapse,orlateralmovementresultingfromhydrodynamicand
hydrostaticloadsduringconditionsofthebaseflood,includingtheeffectsof
buoyancy (assuming the tank is empty);
b.Elevatedabove-groundtanks,infloodhazardareasshallbeattachedtoand
elevatedtoorabovethedesignfloodelevationonasupportingstructurethatis
designedtopreventflotation,collapse,orlateralmovementduringconditionsof
thebaseflood.Tank-supportingstructuresshallmeetthefoundation
requirements of the applicable flood hazard area;
c.Notelevatedabove-groundtanksmaybepermittedinfloodhazardareas
providedthetanksareanchoredorotherwisedesignedandconstructedto
preventflotation,collapseorlateralmovementresultingfromhydrodynamic
andhydrostaticloadsduringconditionsofthedesignflood,includingtheeffects
of buoyancy assuming the tank is empty and the effects of flood-borne debris.
d.Tank inlets, fill openings, outlets and vents shall be:
1.atorabovethefloodprotectionelevationorfittedwithcovers
designedtopreventtheinflowoffloodwateroroutflowofthecontentsof
the tanks during conditions of the base flood; and
2.anchoredtopreventlateralmovementresultingfromhydrodynamic
andhydrostaticloads,includingtheeffectsofbuoyancy,duringconditions
of the base flood.
9. Construction of Below-Grade Crawlspace:
a.TheinteriorgradeofacrawlspacemustnotbebelowtheBFEandmustnot
be more than two (2) feet below the exterior lowest adjacent grade (LAG).
b.Theheightofthebelow-gradecrawlspace,measuredfromtheinteriorgrade
ofthecrawlspacetothetopofthecrawlspacefoundationwall,mustnotexceed
four (4) feet at any point.
c.Theremustbeanadequatedrainagesystemthatremovesfloodwatersfrom
theinteriorareaofthecrawlspace.Theenclosedareashouldbedrainedwithina
reasonable time after a flood event.
d.Thevelocityoffloodwatersatthesiteshouldnotexceedfive(5)feetper
second for any crawlspace.
10. Critical Facilities:
Constructionofnewcriticalfacilitiesshallbe,totheextentpossible,locatedoutside
thelimitsofthespecialfloodhazardarea(SFHA)(100-yearfloodplain).Construction
ORDINANCE 657 AND SUMMARY, UPDATE TO FLOODPLAIN REQUIREMENTS, FEBRUARY 2021
ofnewcriticalfacilitiesshallbepermissiblewithintheSFHAifnofeasiblealternative
siteisavailable.CriticalfacilitiesconstructedwithintheSFHAshallhavethelowest
floorelevatedthreefeet(3')aboveBFEortotheheightofthe500-yearflood,
whicheverishigher.Accesstoandfromthecriticalfacilityshouldalsobeprotectedto
theheightutilizedabove.Floodproofingandsealingmeasuresmustbetakentoensure
thattoxicsubstanceswillnotbedisplacedbyorreleasedintofloodwaters.Access
routeselevatedtoorabovethelevelofthebasefloodelevationshallbeprovidedtoall
critical facilities to the extent possible.
(C) Floodways: Located within areas of special flood hazard establishments in Section
7-10-3 (B) are areas designated as floodways. Since the floodway is an extremely
hazardous area due to the velocity of flood waters which carry debris, potential
projectiles, and erosion potential, the following provisions apply:
1. Prohibit encroachments, including fill, new construction, substantial
improvement,
and other development unless certification by a registered professional engineer or
architect is provided demonstrating that encroachments shall not result in any
increase in flood levels during the occurrence of the base flood discharge.
2. If Section 7-10-5(C)-1 is satisfied, all new construction and substantial
improvements shall comply with all applicable flood hazard reduction provisions
of Section 7-10-5, PROVISIONS FOR FLOOD HAZARD REDUCTION.
3. Prohibit the placement of any mobile homes, except in an existing mobile home
park or existing mobile home subdivision.
(D)Standards for Floodplains without Established Base Flood Elevations
WithintheSpecialFloodHazardAreasdesignatedasZoneA(alsoknownas
UnnumberedAZones)andestablishedin7-10-3(B),wherenoBaseFloodElevation
(BFE)datahasbeenprovidedbyFEMA,thefollowingprovisions,inadditiontothe
provisions of 7-10-5 (A), shall apply:
TheBFEusedindeterminingtheFloodProtectionElevation(FPE)shallbedetermined
based on the following criteria:
1.WhenBaseFloodElevation(BFE)dataisavailablefromothersources,all
newconstructionandsubstantialimprovementswithinsuchareasshallalso
complywithallapplicableprovisionsofthisordinanceandshallbeelevatedor
floodproofed in accordance with standards in 7-10-5 (A) and 7-10-5 (B).
2.WhenfloodwaydataisavailablefromaFederal,State,orothersource,all
newconstructionandsubstantialimprovementswithinfloodwayareasshallalso
comply with the requirements of 7-10-5 (B).
3.Requirethatallnewsubdivisionproposalsandotherproposeddevelopments
(includingproposalsformanufacturedhomeparksandsubdivisions)greaterthan
50lotsor5acres,whicheveristhelesser,includewithinsuchproposalsbaseflood
elevationdata.SuchBaseFloodElevation(BFE)datashallbeadoptedby
referenceinaccordancewithArticleIII,SectionBandutilizedinimplementing
this ordinance. See FEMA 480 and/or FEMA 265 for further information
4. When Base Flood Elevation (BFE) data is not available from a Federal, State, or
other source as outlined above, the lowest floor shall be elevated or floodproofed
(non-residential) to two feet (2.0 ft.) above the Highest Adjacent Grade (HAG) at
the building site or to the Flood Protection Elevation (FPE) whichever is higher, as
defined in 7-10-2. All other applicable provisions of Article V, Section B shall also
apply.
(E) Standards for Shallow Flooding Areas (AO Zones):
ORDINANCE 657 AND SUMMARY, UPDATE TO FLOODPLAIN REQUIREMENTS, FEBRUARY 2021
1. Shallow flooding areas appear in FIRM’s as AO zones with depth designations.
The base flood depths in these zones range from one (1) to three (3) feet 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 these areas, the following provisions apply:
(a) New construction and substantial improvements of residential structures
within AO zones shall have the lowest floor (including basement) elevated
above the adjacent grade of the building site, to or above the depth number
specified on the FIRM (at least two (2) feet if no depth number is specified).
(b) New construction and substantial improvements of nonresidential
structures within AP zones shall either:
(1) The lowest floor (including basement) elevated above the adjacent
grade of the building site, to or above the depth number specified
on the FIRM (at least two (2) feet if no depth number is specified);
or
(2) Together with attendant utility and sanitary facilities, be completely
floodproofed 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 7-10-5 (B) 2(c).
(c) Require adequate drainage paths around structures on slopes to guide
floodwaters around and away from proposed structures.
(d) Shall have flood openings to facilitate automatic equalization of
hydrostatic flood forces shall be provided below Flood Protection
Elevation
7-10-6: REPEALED
7-10-7: ACCESSORY STRUCTURES:
(A) Accessory structures to a main structure shall be defined as those structures which are
utilized in connection with a main structure, but in and of the accessory structure itself
does not constitute a main purpose of function of the improvement. Such accessory
buildings shall include, but not by way of limitation, storage sheds, tool sheds, garden
buildings, greenhouses, detached garages, kennels, and barns.
(B) No such accessory structure shall at any time be used for human habitation.
(C) All such accessory structures shall be designed to have low flood damage potential.
(D)Allsuchaccessorystructuresshallbeconstructedandplaceonthebuildingsitesoas
to offer the minimum resistance to the flow of flood waters.
(E) All such accessory structures shall be firmly anchored to prevent flotation which may
result in damage to other structures.
(F) All service facilities to any such accessory structure such as electrical and heating
ORDINANCE 657 AND SUMMARY, UPDATE TO FLOODPLAIN REQUIREMENTS, FEBRUARY 2021
equipment shall be elevated or floodproofed.
(G) When an accessory structure represents a minimal investment, the elevation or dry
floodproofing standards need not be met. However, all other requirements applicable to
structures will be applicable. A minimal investment shall be determined by the applicable
building authority, or by the appeal under the variance procedure and shall be
determined, if necessary, on a case to case basis. However, as a general application,
expenditure for the accessory structure of not more than ten percent (10%) of the value
of the main structure shall be considered a minimal investment.
7-10-8:FLOODINSURANCESTUDY:ThefloodinsurancestudyfortheCityofAmmon,dated
April2,2002,andanyrevisionsthereto,isherebyadoptedbyreferenceanddeclaredtobeapartof
theordinanceoftheCityofAmmon,forthecontrolanduseofpropertyintheCityofAmmon,
Idaho flood plain.
ThemostcurrentfloodinsurancestudyforBonnevilleCountyshallbeusedforanyproperties
annexedintotheCityofAmmonthatareoutsideoftheCityofAmmonfloodinsurancestudy
maps.
7-10-9:ELEVATIONCERTIFICATESREQUIREDFORALLNEWBUILDINGSINTHE
CITY:
Elevation Certificates for buildings in the floodplain shall be required at the following
times: Elevation Certificates for buildings in the floodplain should be required as follows:
(A)Submittedwithconstructiondrawingsatthetimeofarequestforabuildingpermit
(prior to any alterations of the ground) and
(B) After the foundation or pad has been poured. This certificate should provide the
information showing the lowest floor is at or above the required elevation. The City
Engineer shall certify this.
(C)TheCityEngineerworkingwiththeBuildingDepartmentshallinspectandcertify
thatanyadditionaldevicesorstructuresareinplacepriortothefinalcertificateof
occupancy.
ORDINANCE 657 AND SUMMARY, UPDATE TO FLOODPLAIN REQUIREMENTS, FEBRUARY 2021
STATE OF IDAHO)
) ss.
County of Bonneville)
I, KRISTINA BUCHAN, CITY CLERK OF THE CITY OF AMMON, IDAHO DO HEREBY CERTIFY;
That the above and foregoing is a full, true and correct copy of the Ordinance entitled,
ORDINANCE 657
ANORDINANCEOFTHECITYOFAMMON,OFTHESTATEOFIDAHO,
REPEALINGANDREPLACINGTITLE7,CHAPTER10,FLOODPLAIN
REQUIREMENTS,TOALIGNAMMONMUNICIPALCODEWITH
FEDERALFLOODPLAINDEVELOPMENTSTANDARDS;PROVIDINGA
SEVERABILITYCLAUSE;PROVIDINGAREPEALERCLAUSE;AND
PROVIDING AN EFFECTIVE DATE.
DATED this 11 day of February 11, 2021.
________________________________
Kristina Buchan, City Clerk
ORDINANCE 657 AND SUMMARY, UPDATE TO FLOODPLAIN REQUIREMENTS, FEBRUARY 2021
SUMMARY OF
ORDINANCE NO: #657
ANORDINANCEOFTHECITYOFAMMON,OFTHESTATEOFIDAHO,
REPEALINGANDREPLACINGTITLE7,CHAPTER10,FLOODPLAIN
REQUIREMENTS,TOALIGNAMMONMUNICIPALCODEWITH
FEDERALFLOODPLAINDEVELOPMENTSTANDARDS;PROVIDINGA
SEVERABILITYCLAUSE;PROVIDINGAREPEALERCLAUSE;AND
PROVIDING AN EFFECTIVE DATE.
The full text of this Corrected Ordinance No. 657, is available at the City Clerk’s Office, Ammon
City Office, 2135 S Ammon Road, Ammon, Idaho.
ATTEST:CITY OF AMMON
______________________________________________________________________
Kristina Buchan, City ClerkSean Coletti, Mayor
I have reviewed the foregoing summary and believe that it provides a true and complete summary of
Corrected Ordinance #657 and that the summary provides adequate notice to the public of the contents of
this ordinance.
DATED this 11 day of February, 2021.
________________________________
Scott Hall, City Attorney
ORDINANCE 657 AND SUMMARY, UPDATE TO FLOODPLAIN REQUIREMENTS, FEBRUARY 2021
RIPTION