HomeMy WebLinkAboutOrdinances - MC-06-900 - 11/06/2006 - Chapter 8 Flood Plain RegulationsORDINANCE NO. MC-06-900
An Ordinance Amending City of McHenry Municipal Code
Chapter 8, Flood Plain Regulations
BE IT ORDAINED BY THE CITY COUNCIL OF THE CITY OF MCHENRY,
MCHENRY COUNTY, as follows:
SECTION 1: That Chapter 8, Development in Special Flood Hazard Areas of
the City of McHenry Municipal Code, shall be deleted in its entirety and replaced as
follows:
11/06
CHAPTER 8*
DEVELOPMENT IN SPECIAL FLOOD HAZARD AREAS"
Sec. 8-1.0 Purpose.
This Ordinance is enacted pursuant to the police powers granted to this City by 65 ILCS 5/1-2-1, 5/11-12-12,
5/11-30-2, 5/11-30-8, and 5/11-31-2. The purpose of this Ordinance is to maintain this'City's eligibility in
the National Flood Insurance Program; to minimize potential losses due to periodic flooding including loss
of life, loss of 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; and to preserve and enhance the quality of
surface waters, conserve economic and natural values and provide for the wise utilization of water and
related land resources. This Ordinance is adopted in order to accomplish the following specific purposes:
Sec. 8-1.1 To meet the requirements of 615 ILCS 5/18(g) Rivers, Lakes and Streams Act.
Sec. 8-1.2 To assure that new development does not increase the flood or drainage hazards to others, or
create unstable conditions susceptible to erosion;
Sec. 8-1.3 To protect new buildings and major improvements to buildings from flood damage;
Sec. 8-1.4 To protect human life and health from the hazards of flooding;
Sec. 8-1.5 To lessen the burden on the taxpayer for flood control projects, repairs to flood -damaged
public facilities and utilities, and flood rescue and relief operations;
Sec. 8-1.6 To make federally subsidized flood insurance available for property in the: City by fulfilling
the requirements of the National Flood Insurance Program;
Sec. 8-1.7 To comply with the rules and regulations of the National Flood Insurance Program codified
as 44 CFR 59-79, as amended;
Sec. 8-1.8 To protect, conserve, and promote the orderly development of land and water resources;
Sec. 8-1.9 To preserve the natural characteristics and functions of watercourses and floodplains in order
to moderate flood and stormwater impacts, improve water quality, reduce soil erosion, protect aquatic
and riparian habitat, provide recreational opportunities, provide aesthetic benefits and enhance
community and economic development.
Sec. 8-1.10 Reserved.
* This Chapter 8 - Development in Special Flood Hazard Areas was formerly Article VIII of
Chapter 7 adopted 3-16-81; Ord. No. 0-81-254; amended in entirety March 4, 1992, Ord. No.
MC-92-570; revised MC-92-579.
* * Cross references - Planning and Zoning generally, Ch. 17; water and sewers, Ch. 26.
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Sec. 8-2.0 Definitions.
For the purposes of this Ordinance, the following definitions are adopted:
Sec. 8-2.1 "Accessory Structure" A non -habitable structure which is on the same parcel of property
as the principal structure to be insured and the use of which is incidental to the use of the principal
structure.
Sec. 8-8.2 "Act" An act in relation to the regulation of the rivers, lakes, and streams of the State of
Illinois, 615 ILCS 5/5 et seq
Sec. 8-2.3 "Applicant" Any person, firm, corporation or agency which submits an application.
Sec. 8-2.4 "Appropriate Use" Only uses of the designated floodway that are permissible and will be
considered for permit issuance. The only uses that will be allowed are as specified in Section 802.0.
Sec. 8-2.5 'Base Flood" The flood having a one -percent probability of being equalled or exceeded in
any given year. The base flood is also known as the 100-year frequency flood event. Application of the
base flood elevation at any location is as defined in Section 8-5.0 of this ordinance.
Sec. 8-2.5a "Base Floor Elevation (BFE" The elevation in relation to mean sea level of the crest of the
base flood.
Sec. 8-2.5b "Basement" That portion of the building having its floor subgrade (below ground level) on
all sides.
Sec. 8-2.5c 'Building" A walled and roofed structure, including gas or liquid storage tank, that is
principally above ground, including manufactured homes, prefabricated buildings, and gas or liquid
storage tanks. This term also includes recreational vehicles and travel trailers installed on a site for more
than 180 days per year.
Sec. 8-2.6 "Channel" Any river, stream, creek, brook, branch, natural or artificial depression, ponded
area, flowage, slough, ditch, conduit, culvert, gully, ravine, wash, or natural or man-made drainageway,
which has a definite bed and banks or shoreline, in or into which surface or groundwater flows, either
perennially or intermittently.
Sec. 8-2.7 "Channel Modification" Alteration of a channel by changing the physical dimensions or
materials of its bed or banks. Channel modification includes damming, rip -rapping or other armoring,
widening, deepening, straightening, relocating, lining and significant removal of native vegetation from
the bottom or banks. Channel modification does not include the clearing of dead or dying vegetation,
debris, or trash from the channel. Channelization is a severe form of channel modification typically
involving a significant change in the channel cross-section and typically involving; relocation of the
existing channel (e.g. straightening).
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Sec. 8-2.8 "Compensatory Storage" An artificially excavated, hydraulically equivalent volume of
storage within the SFHA used to balance the loss of natural flood storage capacity when artificial fill or
structures are placed within the flood plain. The uncompensated loss of natural flood plain storage can
increase off -site floodwater elevations and flows.
Sec. 8-2.9 "Conditional Approval of a Designated Floodway Map Change" Preconstruction approval
by IDNR/IDNR/OWR and the Federal Emergency Management Agency (FEMA) of a proposed change
to the floodway map. This preconstruction approval, pursuant to this Part, gives assurances to the
property owner that once an Appropriate Use is constructed according to permitted plans, the floodway
map can be changed, as previously agreed, upon review and acceptance of as -built plans.
Sec. 8-2.10 "Conditional Letter of Map Revision (CLOMR)" A letter which indicates that the Federal
Emergency Management Agency will revise base flood elevations, flood insurance rate zones, flood
boundaries or floodway as shown on an effective Flood Hazard Boundary Map or Flood Insurance Rate
Map, once the as -built plans are submitted and approved.
Sec. 8-2.11 "Control Structure" A structure designed to control the rate of flow that passes through the
structure, given a specific upstream and downstream water surface elevation.
Sec. 8.2.11a "Critical Facility" Any facility which is critical to the health and welfare of the population
and, if flooded, would create an added dimension to the disaster. Damage to these critical facilities can
impact the delivery of vital services, can cause greater damage to other sectors of the community, or can
put special populations at risk. Examples of critical facilities where flood protection should be required
include: emergency services facilities (such as fire and police stations), schools, hospitals, retirement
homes and senior care facilities, major roads and bridges, critical utility sites (telephone switching
stations or electrical transformers), and hazardous material storage facilities (chemicalls, petrochemicals,
hazardous or toxic substances). Examples of critical facilities where flood protection is recommended
include: sewage treatment plants, water treatment plants, and pumping stations.
Sec. 8-2.12 "Dam" All obstructions, wall embankments or barriers, together with their abutments and
appurtenant works, if any, constructed for the purpose of storing or diverting water or creating a pool.
Dams may also include weirs, restrictive culverts or impoundment structures. Underground water
storage tanks are not included.
Sec. 8-2.12a "Designated Floodway" The channel, including on -stream lakes, and that portion of the
floodplain adjacent to a stream or watercourse, generally depicted on the FEMA FIRM map, which is
needed to store and convey the existing 100-year frequency flood discharge with no more than a 0.1 foot
increase in state due to the loss of flood conveyance or storage, and no more than a 10 percent increase
in velocities.
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The floodways are designated for on the countywide Flood Insurance Rate Map of McHenry County
prepared by FEMA and dated November 16, 2006. When two floodway maps exist for a waterway, the
more restrictive floodway limit shall prevail.
The floodways for those parts of unincorporated McHenry County that are within the extraterritorial
jurisdiction of the City that may be annexed into the City are designated for the Fox River, Boone Creek
and Lakeland Park Drainage Ditch on the countywide Flood Insurance Rate Map prepared by FEMA and
dated November 16, 2006.
To locate the designated floodway boundary on any site, the designated floodway boundary should be
scaled off the designated floodway map and located on a site plan, using reference marks common to both
maps. Where interpretation is needed to determine the exact location of the designated floodway boundary,
IDNR/OWR should be contacted for the interpretation.
See. 8-2.13 "Development" Any man-made change to real estate, including:
(a) Construction, reconstruction, repair, or placement of a building or any addition to a building.
(b) Installing a manufactured home on a site, preparing a site for a manufactured home, or installing a
travel trailer or recreational vehicle on a site for more than 180 days. If the travel trailer or recreational
vehicle is on site for less than 180 days, it must be fully licensed and ready for highway use.
(c) Drilling, mining, installing utilities construction of roads, bridges, storage of equipment or materials,
or similar projects.
(d) Demolition of a structure or redevelopment of a site.
(e) Clearing of land as an adjunct of construction.
(f) Construction or erection of levees, walls, fences, dams; or culverts, channel modification; filling,
dredging, grading, excavating, paving, or other non-agricultural alterations of the ground surface;
storage of materials; deposit of solid or liquid waste.
(g) Any other activity of man that might change the direction, height, or velocity of flood or surface
water, including extensive vegetation removal.
(h) Substantial improvement of an existing building.
Development does not include routine maintenance of existing buildings and facilities such as re -roofing
or re -surfacing of roads when there is no increase in elevation, or gardening, plowing, and similar
agricultural practices that do not involve filling, grading or construction of levees.
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Sec. 8-2.14 "IDNR/OWR" Illinois Department of Transportation, Division of Water Resources.
See.8-2.15 "Elevation Certificates" A form published by the Federal Emergency Management
Agency that is used to certify the elevation to which a building has been elevated.
Sec. 8-2.16 "Erosion" The general process whereby soils are moved by flowing water or wave action.
Sec. 8-2.17 "Exempt Organizations" Organizations which are exempt from this ordinance per the ILCS
including state, federal or local units of government.
Sec. 8-2.17a "Existing Manufactured Home Park or Subdivision" A manufactured home park or
subdivision for which the construction of facilities for servicing the lots on which the manufactured
homes are to be affixed (including, at a minimum, the installation of utilities, the construction of streets,
and either final site grading or the pouring of concrete pads) has been completed before; April 1, 1990.
Sec. 8-2.17b "Expansion to an Existing Manufactured Home Park or Subdivision" The preparation of
additional sites by the construction of facilities for servicing the lots on which the manufactured homes
are to be affixed (including the installation of utilities, the construction of streets, and either final site
grading or the pouring of concrete pads.
Sec. 8-2.18 "FEMA" Federal Emergency Management Agency and its regulations at 44 CFR 59-79 as
amended.
Sec. 8-2.19 "Flood" A general and temporary condition of partial or complete inundation of normally
dry land areas from overflow of inland or tidal waves, or the unusual and rapid accumulation or runoff
of surface waters from any source.
Sec. 8-2.20 "Flood Frequency" A period of years, based on a statistical analysis, during which a flood
of a stated magnitude may be expected to be equaled or exceeded.
Sec. 8-2.21 "Flood Fringe" That portion of the flood plain outside of the designated floodway. See
commentary on designated floodway.
Sec.8-2.22 "Flood Insurance Rate Maps (FIRM)" A map prepared by the Federal Emergency
Management Agency that depicts the Special Flood Hazard Area (SFHA) within a community. This
map includes insurance rate zones and flood plains and may or may not depict floodways.
Sec. 8-2.22a "Flood Insurance Study" An examination, evaluation and determination of flood hazards
and if appropriate, corresponding water surface elevations.
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Sec. 8-2.23 "Flood Plain" That land typically adjacent to a body of water with ground surface
elevations at or below the base flood or the 100-year frequency flood elevation. Flood plains may also
include detached Special Flood Hazard Areas, ponding areas, etc. The flood plain is also known as the
Special Flood Hazard Area (SFHA).
The flood plains are those lands within the jurisdiction of the City that are subject to inundation by the
base flood or 100-year frequency flood. The SFHA's of the City are generally identified as such on
panel numbers 17111CO205J, 17111CO206J, 17111CO207J, 17111CO208J, 17111CO209J,
17111CO217J, 17111CO220J, 17111CO226J, 17111CO230J of the countywide Flood Insurance Rate
Map prepared for McHenry County by the Federal Emergency Management Agency and dated
November 16, 2006.
The SFHA's of those parts of unincorporated McHenry County that are within the extraterritorial
jurisdiction of the City or that may be annexed into the City are generally identified as such on panel
number 17111 CIND OA of the countywide Flood Insurance Rate Map prepared for McHenry County
by the Federal Emergency Management Agency and dated November 16, 2006.
Sec. 8-2.24 "Floodproofing" Any combination of structural and non-structural additions, changes or
adjustments to structures which reduce or eliminate flood damage to real estate or improved real
property, water and sanitary facilities, structures and their contents.
Sec. 8-2.25 "Floodproofing Certificate" A form published by the Federal Emergency Management
Agency that is used to certify that a building has been designed and constructed to be structurally dry
floodproofed to the flood protection elevation.
Sec. 8-2.26 "Flood Protection Elevation (FPE)" The elevation of the base flood or 100-year frequency
flood plus one foot of freeboard at any given location in the SFHA.
Sec. 8-2.26a "Floodway" See Designated Floodway.
Sec. 8-2.27 "Freeboard" An increment of elevation added to the base flood elevation to provide a
factor of safety for uncertainties in calculations, unknown localized conditions, wave actions and
unpredictable effects such as those caused by ice or debris jams.
Sec. 8-2.27.1 Historic Structure" Any structure that is:
(a) Listed individually in the National Register of Historic Places or preliminarily determined by the
Secretary of the Interior as meeting the requirements for individual listing on the National Register;
(b) Certified or preliminarily determined by the Secretary of the Interior as contributing to the historic
district or a district preliminarily determined by the Secretary to qualify as a registered historic district;
(c) Individually listed on the State inventory of historic places that has been certified by the Illinois
Historic Preservation Agency;
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(d) Individually listed on a local inventory of historic places that has been certified by the Illinois
Historic Preservation Agency.
Sec. 8-2.28 "Hydrologic and Hydraulic Calculations" Engineering analysis which determine expected
flood flows and flood elevations based on land characteristics and rainfall events.
Sec. 8-2.28a "IDNR/PWR" Illinois Department of Natural Resources, Office of Water Resources
Sec. 8-2.29 "Letter of Map Amendment (LOMA)" Official determination by FEN/ -[A that a specific
structure is not in a 100-year flood plain; amends the FIRM.
Sec. 8-2.30 "Letter of Map Revision (LOMR)" Letter that revises base flood or 100-year frequency
flood elevations, flood plains, or floodways, as shown on an effective FIRM.
Sec. 8-2.30a "Lowest Floor" The lowest floor of the lowest enclosed area (including basement). An
unfinished or flood resistant enclosure usable solely for parking of vehicles, building access or storage,
in an area other than a basement area is not considered a building's lowest floor, provided that such
enclosure is not built so as to render the structure in violation of the applicable non -elevation design
requirements of this ordinance.
Sec. 8-2.31 "Manufactured Home" A structure, transportable in one or more sections, which is built
on a permanent chassis and is designated for use with or without a permanent foundation when
connected to the required utilities. The term manufactured home also includes park trailers, travel
trailers, and other similar vehicles placed on site for more than 180 consecutive days. The term
manufactured home does not include a "recreational vehicle".
Sec. 8-2.32 "Manufactured Home Park or Subdivision" A parcel (or contiguous parcels) of land
divided into two or more manufactured home lots for rent or sale.
Sec. 8-2.33 "Mitigation" Mitigation includes those measures necessary to minimize the negative
effects which flood plain development activities might have on the public health, safety and welfare.
Examples of mitigation include excavation of compensatory storage, soil erosion and sedimentation
control, and channel restoration. Mitigation may also include those activities taken to reduce a
structure's susceptibility to flooding.
Sec.8.2.33a "NAVD 88" National American Vertical Datum of 1988. NAVD 88 supersedes the
National Geogectic Vertical Datum of 1929
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Sec. 8-2.34 "Natural" When used in reference to channels means those channels formed by the
existing surface topography of the earth prior to changes made by man. A natural stream tends to follow
a meandering path; its flood plain is not constrained by levees; the area near the bank has not been
cleared, mowed or cultivated; the stream flows over soil and geologic materials typical of the area with
no substantial alteration of the course of cross-section of the stream caused by filling or excavating. A
modified channel may regain some natural characteristics over time as the channel meanders and
vegetation is re-established. Similarly, a modified channel may be restored to more natural conditions
by man through re -grading and re -vegetation
Sec. 8-2.34a "New Construction" New Construction means structures for which the start of
construction commenced on or after the effective date of a flood plain management regulation adopted
by a community and includes any subsequent improvements to such structures.
Sec. 8.2.35 "New Manufactured Home Park or Subdivision" Manufactured home park or subdivision
for which the construction of facilities for servicing the lots on which the manufactured homes are to be
affixed (including at a minimum, the installation of utilities, the construction of streets, and either final
site grading or the pouring of concrete pads) has been completed on or after April 1, 19,90.
Sec. 8-2.36 "Ordinary High Water Mark (OHWM)" The point on the bank or shore up to which the
presence and action of surface water is so continuous so as to leave a distinctive mark such as by
erosion, destruction or prevention of terrestrial vegetation, predominance of aquatic vegetation or other
easily recognized characteristics.
Sec. 8-2.37 "Public Flood Control Project" A flood control project which will be operated and
maintained by a public agency to reduce flood damages to existing buildings and structures which
includes a hydrologic and hydraulic study of the existing and proposed conditions of the watershed.
Nothing in this definition shall preclude the design, engineering, construction or financing, in whole or
in part, of a flood control project by persons or parties who are not public agencies.
Sec. 8-2.38 "Public Bodies of Water" All open public streams and lakes capable of being navigated by
watercraft, in whole or in part, for commercial uses and purposes, and all lakes, rivers, and streams
which in their natural condition were capable of being improved and made navigable, or that are
connected with or discharge their waters into navigable lakes or rivers within, or upon the borders of the
State of Illinois, together with all bayous, sloughs, backwaters, and submerged lands that are open to the
main channel or body of water directly accessible thereto.
Sec. 8-2.38a "Recreational Vehicle or Travel Trailer" A vehicle which is:
(a) Built on a single chasis;
(b) 400 sf or less when measured at the largest horizontal projection;
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(c) Designed to be self-propelled or permanently towable by a light duty truck; and
(d) Designed primarily not for use as a permanent dwelling but as temporary living quarters for
recreational, camping, travel or seasonal use.
Sec. 8.2.38b `Regional Permits" Regional permits are offered for pre -approved projects which are
considered minor projects that are permissible per IDNR/OWR Part 3708 rules for Northeastern Illinois
designated floodways. A complete listing of the terms and conditions for specific project types can be
obtained from the IDNR/OWR website.
Sec. 8-2.39 "Registered Land Surveyor" A land surveyor registered in the State of Illinois under The
Illinois Land Surveyors Act (225 ILCS 330/1 et seq).
Sec. 8-2.40 "Registered Professional Engineer" An engineer registered in the State of Illinois, under
The Illinois Professional Engineering Act (225 ILCS 325/1 et seq).
Sec.8-2.41 Reserved
Sec. 8-2.42 "Repair, Remodeling or Maintenance" Development activities which do not result in any
increases in the outside dimensions of a building or any changes to the dimensions of a structure.
Sec. 8-2.42a "Repetitive Loss" Flood -related damages sustained by a structure on two separate
occasions during a ten-year period for which the cost of repairs at the time of each flood event, on the
average, equals or exceeds 25 percent of the market value of the structure before the damage occurred.
Sec. 8-2.43 "Retention/Detention Facility" A retention facility stores stormwater runoff without a
gravity release. A detention facility provides for storage of stormwater runoff and controlled release of
this runoff during and after a flood or storm.
Sec. 8-2.44 "Riverine SFHA" Any SFHA subject to flooding from a river, creek, intermittent stream,
ditch, on -stream lake system or any other identified channel. The term does not include areas subject to
flooding from lakes, ponding areas, areas of sheet flow, or other areas not subject to overbank flooding.
Sec. 8-2.45 "Runoff' The water derived from melting snow or rain falling on the land surface, flowing
over the surface of the ground or collected in channels or conduits.
Sec. 8-2.46 "Sedimentation" The processes that deposit soils, debris, and other materials either on
other ground surfaces or in bodies of water or watercourses.
Sec. 8-2.47 "Special Flood Hazard Area (SFHA)" See Flood Plain.
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Sec. 8-2.47a "Start of Construction" Includes substantial improvement, and means the: date the building
permit was issued, provided the actual start of construction, repair, reconstruction, rehabilitation,
addition placement, or other improvement was within 180 days of the permit date. The actual start
means either the first placement of permanent construction of a structure on a site, such as the pouring of
slab or footings, the installation of piles, the construction of columns, or any work beyond the stage of
excavation; or placement of a manufactured home on a foundation.
Sec. 8-2.47b "Statewide Permits" Statewide permits are offered for pre -approved projects that are
considered minor projects which are permissible per the IDNR/OWR Part 3700 rules. A complete listing
of the statewide permits and permit requirements can be obtained from the IDNR/OWR website.
Sec. 8-2.48 "Structure" See Building.
Sec. 8-2.48a "Substantial Damage" Damage of any origin sustained by a structure whereby the
cumulative percentage of damage subsequent to the adoption of this ordinance equals or exceeds 50
percent of the market value of the structure before the damage occurred regardless of actual repair work
performed. Volunteer labor and materials must be included in this determination. For term Repetitive
Loss Buildings see Repetitive Loss.
Sec. 8-2.49 "Substantial Improvement" Any reconstruction, rehabilitation, addition or improvement of
a structure, taking place subsequent to the adoption of this ordinance in which the cumulative percentage
of improvement equals or exceeds 50 percent of the market value of the stnicture before the
improvement or repair started.
Substantial Improvement is considered to occur when the
other structural part of the building commences, whethe
The term does not, however, include either:
r
(a) any project for improvement of a structure to comply with existing state or local health, sanitary, or
safety code specifications which are solely necessary to assure safe living conditions; or
(b) any alteration of an "historic structure" listed on the National Register of Historic Places or the
Illinois Register of Historic Places, provided that the alteration will not preclude the structure's
continued designation as an historic structure.
Sec. 8-2.50 "Transition Section" Reaches of the stream or floodway where water flows from a narrow
cross-section to a wide cross-section or vice versa.
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Sec. 8-2.51 "Violation" The failure of a structure or other development to be fully compliant with the
community's flood plain management regulations. A structure or other development without the
elevation certificate, other certification, or other evidence of compliance is presumed to be in violation
until such time as that documentation is provided.
Sec. 8-3.0 How to use this ordinance
The Building Officer shall be responsible for fulfilling all of the duties listed in Section 8-4.0.
To fulfill those duties, the Building Officer first should use the criteria listed in Section 8-5.0,
Base Flood Elevations, to determine whether the development site is located within a floodplain. Once
it has been determined that a site is located within a flood plain, the Building Officer must determine
whether the development site is within a flood fringe, a designated floodway, or within a SFHA or flood
plain on which no floodway has been identified. If the site is within a flood fringe, the Building Officer
shall require that the minimum requirements of Section 8-6.0 be met. If the site is within a floodway,
the Building Officer shall require that the minimum requirements of Section 8-7.0 be met. If the site is
located within a SFHA or flood plain for which no detailed study has been completed and approved, the
Building Officer shall require that the minimum requirements of Section 8-8.0 be met.
In addition, the general requirements of Section 8-9.0 shall be met for all developments meeting
the requirements of Section 8-6.0, 8-7.0, or 8-8.0. The Building Officer shall assure that all subdivision
proposals shall meet the requirements of Section 8-10.0.
If a variance is to be granted for a proposal, the Building Officer shall review the requirements of
Section 8-11.0 to make sure they are met. In addition, the Building Officer shall complete all
notification requirements.
In order to assure that property owners obtain permits as required in this Ordinance, the Building
Officer may take any and all actions as outlined in Section 8-13.0.
Sec. 8-4.0 Duties of the Building Officer.
The Building Officer shall be responsible for the general administration and enforcement of this
Ordinance which shall include the following:
Sec. 8-4.1 Determining the flood plain designation. Check all new development sites to determine
whether they are in a Special Flood Hazard Area (SFHA). If they are in a SFHA, determine whether
they are in a floodway, flood fringe or a flood plain on which a detailed study has not been conducted
and which drains more than one (1) square mile.
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Check whether the development is potentially within an extended SFHA (with a drainage area less
than one square mile), indicating that the development would have adverse impacts regarding storage,
conveyance, or inundation which would be the basis for the applicant being required to delineate the
floodplain and floodway and be subject to the remaining Sections of this ordinance.
Sec. 8-4.2 Professional engineer review. If the development site is within a floodway or in a flood plain
on which a detailed study has not been conducted and which drains more than one (1) square mile, the
permit shall be referred to a registered professional engineer (P.E.) under the employ or contract of the
City for review to ensure that the development meets the requirements of Section 8-7.0 or Section 8-8.0.
In the case of an Appropriate Use, the P.E. shall state in writing that the development meets the
requirements of Section 8-7.0.
Sec. 8-4.3 Dam safety requirements. Dams are classified as to their size and their hazard damage
potential in the event of failure. The construction or major modification of all Class I (high hazard) and
Class II (moderate hazard) dams requires an IDNR/OWR dam safety permit. Some Class III (low
hazard) dams require an IDNR/OWR dam safety permit, depending on the drainage area to the dam, the
height of the dam and the impounding capacity behind the dam. Most off -channel detention basins that
have an embankment are non jurisdictional Class III dams. It is not required that IDNRLOWR sign off on
all non jurisdictional Class III dams.
A consulting engineer with dam safety knowledge can estimate a hazard classification and determine if
an IDNR/OWR dam safety permit is required. A permit application submittal must be made to
IDNR/OWR for the construction or major modification of jurisdictional dams. Regulated dams may
include weirs, restrictive culverts or impoundment structures.
Sec. 8-4.4 Other permit requirements. Ensure that any and all required federal, state and local permits
are received prior to the issuance of a flood plain development permit.
Sec. 8-4.5 Plan review and permit issuance. Ensure that all development activities within the SFHAs of
the jurisdiction of the City meet the requirements of this ordinance and issue a flood 1 lain development
permit in accordance with the provisions of this ordinance and other regulations of this community when
the development meets the conditions of this ordinance.
Sec. 8-4.6 Inspection review. Inspect all development projects before, during and after construction to
assure proper elevation of the structure and to ensure they comply with the provisions of this Ordinance.
Schedule on an annual basis an inspection of the flood plain and document the results of the inspection.
Sec. 8-4.6a Damage Determinations. Make damage determinations of all damaged buildings in the
SFHA after a flood to determine substantially damaged structures which must comply with Section
8.9.0.
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Sec. 8-4.7 Elevation and floodproofing certificates. Maintain in the permit files including:
(a) an Elevation Certificate certifying the elevation of the lowest floor (including basement) of a
residential or non-residential building subject to Section 8.9.0; and/or
(b) the elevation to which a non-residential building has been floodproofed, using a Floodproofing
Certificate, for all buildings subject to Section 8-9.0 of this ordinance.;
Sec. 8-4.8 Records for public inspection. Maintain for public inspection and furnish capon request base
designated floodway maps, copies of federal or state permit documents, variance documentation,
Conditional Letter of Map Revision, Letter of Map Revision, Letter of Map Amendment, and "as built"
elevation and floodproofing and/or elevation certificates for all buildings constructed subject to this
ordinance.
Sec. 8-4.9 State permits. Ensure that construction authorization has been granted by the IDNR, for all
development projects subject to Sections 8-7.0 and 8-8.0 of this ordinance, unless enforcement
responsibility has been delegated to the City. However, the following review approvals are not delegated
to the City and shall require review or permits from IDNR/OWR:
(a) Organizations which are exempt from this ordinance, as per the ILCS,
(b) IDNR/OWR projects, dams or impoundment structures as defined in Section 8-2.12 and all other
state, federal or local unit of government projects, including projects of the City and County, except for
those projects meeting the requirements of Sec. 8-7.9.
(c) An engineer's determination that an existing bridge or culvert crossing is not a source of flood
damage and the analysis indicating the proposed flood profile, per Section 8-7.5(e).
(d) An engineer's analysis of the flood profile due to Section 8-7.5(d);
(e) Alternative transition sections and hydraulically equivalent compensatory storage as indicated in
Section 8-7.5(a, b and h);
(f) Permit issuance of structures within, under or over publicly navigable rivers, lakes and streams;
(g) Any changes in the mapped floodway or published flood profiles.
Sec. 8-4.10 Cooperation with other agencies. Cooperate with state and federal flood plain management
agencies to improve base flood or 100-year frequency flood and floodway data and to improve the
administration of this ordinance. Submit data to IDNR/OVWR and FEMA for proposed revisions of a
designated map within six months whenever a modification of the floodplain may change the base flood
elevation or result in a change in the floodplain map.. Submit reports as required for -the National Flood
Insurance Program. Notify FEMA of any proposed amendments to this ordinance.
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See. 8-4.11 Promulgate regulations. Promulgate rules and regulations as necessary -to administer and
enforce the provisions of this ordinance, subject however to the review and approval of IDNR/OWR and
FEMA for any ordinance changes.
Sec. 8-5.0 Base flood elevation
This Ordinance's protection standard is based on the Flood Insurance Study for the City. If a base
flood elevation or 100-year frequency flood elevation is not available for a particular site, then the
protection standard shall be according to the best existing data available from federal, state or other
sources. When a party disagrees with the best available data, they shall submit a detailed engineering
study needed to replace existing data with better data and submit it to IDNR/OWR and FEMA for
review and consideration prior to any development of the site.
See. 8-5.1 The base flood or 100-year frequency flood elevation for the SFHSAs of Fox River, Boone
Creek, and the Lakeland Park drainage ditch, shall be as delineated on the 100-year flood profiles in the
Flood Insurance Study of the City prepared by FEMA and dated November 16, 2006, and such
amendments to such study and maps as may be prepared from time to time.
Sec. 8-5.2 The base flood or 100-year frequency flood elevation for the SFHAs of those parts of
unincorporated McHenry County that are within the extra -territorial jurisdiction of the City, or that may
be annexed into the City shall be as delineated on the 100-year flood profiles in the Flood Insurance
Study of McHenry County prepared by FEMA and dated November 16, 2006, and such amendments or
revisions to such study and maps as may be prepared from time to time.
See. 8-5.3 The base flood or 100-year frequency flood elevation for each SFHA delineated as an "AH
Zone" or "AO Zone" shall be that elevation (or depth) delineated on the Flood Insurance Rate Map of
McHenry County.
Sec. 8-5.4 The base flood or 100-year frequency flood elevation for each of the remaining SFHAs
delineated as an "A Zone" on the Flood Insurance Rate Map of McHenry County shall be according to
the best existing data available from federal, state or other sources. Should no other data exist, an
engineering study must be financed by the applicant to determine base flood elevations.
When no base flood or 100-year frequency flood elevation exists, the base flood or 100-year frequency
flood elevation for a riverine SFHA shall be determined from a backwater model, such as HEC-H, HEC-
RAS or a dynamic model such as HIP.
The flood flows used in the hydraulic models shall be obtained from a hydrologic model, such as
HEC-HMS, HEC-I, TR-20 or HIP, or by techniques presented in various publications prepared by the
United States Geological Survey for estimating peak flood discharges.
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For a non-riverine SFHA, the Base Flood Elevation shall be the historic Flood of Record plus three (3)
feet, unless calculated by a detailed engineering study.
For an unmapped extended SFHA (with drainage area less than one square mile) which has been
identified by the Building Officer pursuant to Section 8.4, the base flood elevation shall be determined
by the applicant utilizing a method as approved in Section 8.5.
See. 8-6.0 Occupation and use of flood fringe areas
Development in and/or filling of the flood fringe will be permitted if protection is provided
against the base flood or 100-year frequency flood by proper elevation, and compensatory storage and
other applicable provisions of this ordinance are met. No use will be permitted which adversely affects
the capacity of drainage facilities or systems. Developments located within the flood fringe shall meet
the requirements of this section, along with the requirements of Section 8-9.0.
See. 8-6.1 Development permit. No person, firm, corporation, or governmental body not exempted by
state law shall commence any development in the SFHA without first obtaining a development permit
from the Building Officer.
Sec. 8-6.2 Application for a development permit shall be made on a form provided by the Building
Officer. The application shall be accompanied by drawings of the site, drawn to scale, showing property
line dimensions and legal description of the property and sealed by a licensed engineer, architect or land
surveyor; existing grade elevations using the North American Vertical Datum of 1988, and all changes
in grade resulting from excavation or filling; the location and dimensions of all buildings and additions
to buildings. For all proposed buildings, the elevation of the lowest floor (including basement) and
lowest adjacent grade shall be shown on the submitted plans and the development will be subject to the
requirements of Section 8-9.0 of this ordinance.
Section 8-6.3 Upon receipt of a development permit application, the Building Officer shall compare the
elevation of the site to the base flood or 100-year frequency flood elevation of the site; to the base flood
or 100-year frequency flood elevation. Any development located on land that can be shown to be higher
than the base flood elevation of the current Flood Insurance Rate Map and which has not been filled
after the date of the site's first Flood Insurance Rate Map without a permit as required by this ordinance
is not in the SFHA and, therefore, not subject to the requirements of this ordinance. Conversely, any
development located on land shown to be below the base flood elevation and hydraulically connected,
but show on the current Flood Insurance Rate Map is subject to the provisions of this ordinance.. The
Building Official shall maintain documentation of the existing ground elevation at the; development site
and certification that this ground elevation existed prior to the date of the site's first Flood Insurance
Rate Map identification.
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Sec. 8-6.4 A soil erosion and sedimentation control plan for disturbed areas shall be submitted. This
plan shall include a description for the sequence of grading activities and the temporary sediment and
erosion control measures to be implemented to mitigate their effects. This plan shall also include a
description of final stabilization and revegetation measures, and the identification of a responsible party
to ensure post -construction maintenance.
Sec. 8-6.5 The Building Officer shall be responsible for obtaining from the applicant, copies of all other
local, state and federal permits, approvals or waivers that may be required for this type of activity. The
Building Officer shall not issue a permit unless all other local, state and federal permits have been
obtained.
Sec. 8-6.6 Preventing increased damages. No development in the flood fringe shall create a threat to
public health and safety.
Sec. 8-6.7 If fill is being used to elevate the site above the base flood or 100-year frequency flood
elevation, the applicant shall submit sufficient data and obtain a Letter of Map Revision (LOMR) from
FEMA for the purpose of removing the site from the flood plain.
Sec. 8-6.8 Compensatory storage. Whenever any portion of a flood plain is authorized for use, the
volume of space which will be occupied by the authorized fill or structure below the base flood or
100-year frequency flood elevation shall be compensated for and balanced by a hydraulically equivalent
volume of excavation taken from below the base flood or 100-year frequency flood elevation. The
excavation volume shall be at least equal to 1.5 times the volume of storage lost due to the fill or
structure. In the case of streams and watercourses, such excavation shall be made opposite or adjacent
to the areas so filled or occupied. All flood plain storage lost below the existing 10-year flood elevation
shall be replaced below the proposed 10-year flood elevation. All flood plain storage lost above the
existing 10-year flood elevation shall be replaced above the proposed 10-year flood elevation. All such
excavations shall be constructed to drain freely and openly to the watercourse.
Sec. 806.9 Construction of the Lowest Floor below the Base Flood Elevation (BFE).
A person who has obtained a Letter of Map Revision Based on Fill that removes a site in the flood fringe
from the floodplain due to the use of fill to elevate the site above the BFE, may apply for a permit from
the City to construct the lowest floor of a residential building below the BFE in the flood fringe. The
Building Officer shall not issue such a permit unless the applicant has complied with all the criteria set
forth in the following subsection.
(a) Compensatory storage shall be provided per Section 8-6.8
(b) The elevation of the lowest opening in the basement wall (i.e., window wells, access ways) shall be
at or above the Flood Protection Elevation (FPE).
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(c) The lowest adjacent grade to the foundation shall be at or above the FPE, for a minimum distance of
ten (10) feet beyond the outside face of the structure. However, if site conditions are such that this
requirement cannot be met, the Building Officer may waive the ten (10) foot minimum setback if an
Illinois Registered Professional Engineer certify that an alternative method to protect the building from
damage due to hydrostatic pressures has been met. The certifications shall be in the form of a detailed
soils and structural design analysis, which shall be submitted to the Building Officer for review. The
Building Officer may require such additional documentation as necessary to prove that the proposed
shorter setback distance will keep the structure reasonably safe. In no case shall the setback distance be
less than four (4) feet.
(d) The grade around the perimeter of the structure, measured at a distance of twenty (20) feet from the
structure, shall be above the BFE. However, if site conditions are such that this requirement cannot be
obtained, the Building Officer may waive the twenty (20) foot minimum setback distance if an Illinois
Registered Professional Engineer certifies that an alternative method to protect the building from
damages due to hydrostatic pressures have been met. A detailed soils analysis and structural design
proving that a shorter setback distance will keep the structure reasonably safe from flooding, shall be
submitted to the City for review. In no case shall the setback distance be less than four (4) feet.
(e) The ground around the building shall be compacted fill that meets all requirements of this subsection
and is at least five (5) feet thick under the basement floor slab. Nothing in this subsection shall be
interpreted to require the removal or replacement of fill that was placed as part of a LOMR-F, if such fill
consists of material, including soils of similar classification and degree permeability, such as those
classified as CH, CL, SC or ML according to ASTM standard D-2487, Classification of Soils for
Engineering Purposes.
(f) The fill material must be homogeneous and isotropic; that is, the soil must be all of one material, and the
engineering priorities must be in the same direction.
(g) All fill material and compaction shall be designed, certified and inspected by an Illinois Registered
Professional Engineer, as warranted by the site conditions.
(h) The basement floor shall be at an elevation that is no more than five (5) below the BFE.
(i) There shall be a granular drainage layer beneath the floor slab, and minimum of one quarter ('/4)
horsepower sump pump with a backup power supply shall be provided to remove seepage flow. The pump
shall be rated at four (4) times the estimated seepage rate and shall discharge above the BFE and away from
the building in order to prevent flooding of the basement or uplift of the floor under the effect of the
seepage pressure.
0) The drainage system shall be equipped with a positive means of preventing backflow.
(k) All foundation elements shall be designed to withstand hydrostatic pressure in accordance with accepted
engineering practices
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(1) If the applicant is unable to meet all of the requirements set forth in the preceding paragraphs of this
subsection, the Building Officer may allow the construction of a basement below the BFE only if the
applicant demonstrates that the proposed fill and structure meet the guidelines and requirements set forth in
FEMA Technical Bulletin 10-01 and are reasonably safe from flooding. In order to demonstrate that the
proposed structure is reasonably safe from flooding, the applicant shall submit a detailed engineering
analysis of the proposed fill and foundation wall. The engineered basement study shall be completed in
accordance with the latest edition of FEMA Technical Bulletin 10-01, with the analysis of the fill being
prepared by an Illinois Registered Professional Engineer.
(m) In order to provide the required compensatory storage on site, in no case shall the depth of excavation
in the front and side yards of the lot exceed eighteen (18) inches, as measured from the previously existing
natural grade. The rear yard shall be permitted to have a greater depth of excavation, if necessary. All such
excavation shall be constructed to drain freely and openly to the watercourse or storm sewer system. The
use of mechanical means to drain the compensatory storage area will not be permitted.
Sec. 8-7.0 Occupation and use of identified floodways
This section applies to proposed development, redevelopment, site modification or building
modification within a designated floodway. The designated floodway for the Fox River, Boone Creek,
and the Lakeland Park drainage ditch shall be as delineated on the countywide Flood Insurance Rate
Map of McHenry County and referenced in Section 8-2.41. Only those uses and structures will be
permitted which meet the criteria in this section. All floodway modifications shall be the minimum
necessary to accomplish the purpose of the project. The development shall also meet. the requirements
of Section 8-9.0.
Sec. 8-7.1 Development permit. No person, firm, corporation or governmental body not exempted by
state law shall commence any development in a floodway without first obtaining a development permit
from the Building Officer and IDNR/OWR.
Sec. 8-7.2 Application for a development permit shall be made on a form provided by the Building
Officer. The application shall include the following information:
(a) Name and address of applicant;
(b) Site location (including legal description) of the property, drawn to scale, on the designated
floodway map, indicating whether it is proposed to be in an incorporated or unincorporated area,
(c) Name of stream or body of water affected;
(d) Description of proposed activity;
(e) Statement of purpose of proposed activity;
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(f) Anticipated dates of initiation and completion of activity;
(g) Name and mailing address of the owner of the subject property if different from the applicant;
(h) Signature of applicant or the applicant's agent;
(i) If the applicant is a corporation, the president or other authorized officer shall sign the application
form;
0) If the applicant is a partnership, each partner shall sign the application form;
(k) If the applicant is a land trust, the trust officer shall sign the name of the trustee by him (her) as trust
officer. A disclosure affidavit shall be filed with the application, identifying each beneficiary of the trust
by name and address and defining the respective interests therein;
(1) Plans of the proposed activity shall be provided which include as a minimum:
(i) A vicinity map showing the site of the activity, name of the waterway, boundary lines, names
of roads in the vicinity of the site, graphic or numerical scale, and north arrow;
(ii) A plan view of the project and engineering study reach showing existing and proposed
conditions including principal dimensions of the structure or work, elevations,, using the North
American Vertical Datum of 1988, adjacent property lines and ownership, drainage and flood
control easements, location of any channels and any existing or future access roads, distance
between proposed activity and navigation channel (when the proposed construction is near a
commercially navigable body of water), designated floodway limit, flood plain limit,
specifications and dimensions of any proposed channel modifications, location and orientation of
cross -sections, north arrow, and a graphic or numerical scale;
(iii) cross-section views of the project and engineering study reach showing existing and
proposed conditions including principal dimensions of the work as shown in plan view, existing
and proposed elevations, normal water elevation, 10-year frequency flood elevation, 100-year
frequency flood elevation, and graphic or numerical scales (horizontal and vertical).
(iv) A soil erosion and sedimentation control plan for disturbed areas. This plan shall include a
description for the sequence of grading activities and the temporary sediment and erosion control
measures to be implemented to mitigate their effects. This plan shall also include a description
of final stabilization and revegetation measures, and the identification of a responsible party to
ensure post -construction maintenance.
(v) A copy of the designated floodway map, marked to reflect any proposed change in the
designated floodway location.
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(m) Any and all other local, state and federal permits or approval letters that may be required for this
type of development.
(n) Engineering calculations and supporting data shall be submitted showing that the proposed work will
meet the permit criteria of Section 8-7.4.
(o) If the designated floodway delineation, base flood or 100 year frequency flood elevation will change
due to the proposed project, the application will not be considered complete until IDNR/OVWR has
indicted conditional approval of the designated floodway map change. No structures may be built until
a Letter of Map Revision has been approved by FEMA.
(p) The application for a structure shall be accompanied by drawings of the site, drawn to scale showing
property line dimensions and existing ground elevations and all changes in grade resulting from any
proposed excavation or filling, and flood plain and floodway limits; sealed by a registered professional
engineer, licensed architect or registered land surveyor; the location and dimensions of all buildings and
additions to buildings; and the elevation of the lowest floor (including basement) of all proposed
buildings subject to the requirements of Section 8-9.0 of this ordinance.
(q) If the proposed project involves a channel modification, the applicant shall submit the following
information:
(i) A discussion of the purpose of and need for the proposed work;
(ii) A discussion of the feasibility of using alterative locations or methods to accomplish the
purpose of the proposed work;
(iii) An analysis of the extent and permanence of the impacts each feasible alternative identified in
Section 8.7 would have on the physical and biological conditions of the body of water affected;
(iv) An analysis of the extent and permanence of the impacts each feasible alternative identified in
8-7.5 (d)(i) of this Section would have on the physical and biological conditions of the body of
water affected; and
(v) An analysis of the impacts of the proposed project, considering cumulative effects on the
physical and biological conditions of the body of water affected.
Sec. 8-7.3 The Building Officer shall be responsible for obtaining from the applicant copies of all other
local, state, and federal permits and approvals that may be required for this type of activity.
The Building Officer shall not issue the development permit unless all required federal and state
permits have been obtained. A Registered Professional Engineer, under the employ or contract of the
City shall review and approve applications reviewed under this Section.
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Sec. 8-7.4 Preventing increased damages and a list of Appropriate Uses. The only development in a
floodway which will be allowed are Appropriate Uses, which will not cause a rise in the base flood
elevation, and which will not create a damaging or potentially damaging increase in flood heights or
velocity or be a threat to public health and safety and welfare or impair the naturELI hydrologic and
hydraulic functions of the floodway or channel, or permanently impair existing water quality or aquatic
habitat.. Construction impacts shall be minimized by appropriate mitigation methods as called for in
this ordinance. Only those Appropriate Uses listed in 17 Ill. Adm. Code Part';708 will be allowed.
The approved Appropriate Uses are as follows:
(a) Flood control structures, dikes, dams and other public works or private improvements relating to the
control of drainage, flooding, erosion, or water quality or habitat for fish and wildlife.
(b) Structures or facilities relating to the use of, or requiring access to, the water or shoreline, such as
pumping and treatment facilities and facilities and improvements related to recreational boating,
commercial shipping and other functionally water dependent uses;
(c) Storm and sanitary sewer outfalls;
(d) Underground and overhead utilities;
(e) Recreational facilities such as playing fields and trail systems including any related fencing (at least
50% open when viewed from any one direction) built parallel to the direction of flood flows, and
including open air pavilions and toilet facilities (four -stall maximum) that will not block flood flows nor
reduce floodway storage;
(f) Detached garages, storage sheds, or other non -habitable accessory structures that will not block flood
flows, nor reduce floodway storage;
(g) Bridges, culverts, roadways, sidewalks, railways, runways and taxiways and any modification
hereto;
(h) Parking lots built at or below existing grade where either:
(i) the depth of flooding at the 100-year frequency flood event will not exceed 1.0'; or
(ii) the applicant of a short-term recreational use facility parking lot formally agrees to restrict
access during overbank flooding events and accepts liability for all damage caused by vehicular
access during all overbank flooding events;
(i) Designated floodway regrading, without fill, to create a positive non -erosion slope toward a
watercourse.
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0) Flood proofing activities to protect previously existing lawful structures including the construction of
water tight window wells, elevating structures, or construction of floodwalls around residential,
commercial or industrial principal structures where the outside toe of the floodwall shall be no more
than ten (10) feet away from the exterior wall of the existing structure, and, which are not considered
substantial improvements to the structure.
(k) The replacement, reconstruction or repair of a damaged building, provided that the outside
dimensions are not increased, and if the building was damaged to fifty percent (500i6) or more of the
market value before the damage occurred, the building will be protected from flooding to the flood
protection elevation.
(1) Modifications to an existing building that would not increase the enclosed floor area of the building
below the 100-year frequency flood elevation, and which will not block flood flows including but not
limited to, fireplaces, bay windows, decks, patios, and second story additions. If the building is
improved to fifty percent (501/o) or more of the market value before the modification occurred (i.e. a
substantial improvement), the building will be protected from flooding to the flood protection elevation.
Sec. 8-7.4a Appropriate uses do not include the construction or placement of any new structures, fill,
building additions, building on stilts, excavation or channel modifications done to accommodate
otherwise non -appropriate uses in the floodway, fencing (including landscaping or planting designed to
act as a fence) and storage of materials except as specifically defined above as an Appropriate Use.
Sec. 8-7.5 Within the designated floodway, the construction of an Appropriate Use, will be considered
permissible provided that the proposed project meets the following engineering and mitigation criteria
and is so stated in writing with supporting plans, calculations and data by a registered professional
engineer and provided that any structure meets the protection requirements of Section 8.9 of this
ordinance:
(a) Preservation of Flood Conveyance, so as not to increase flood stages upstream. For appropriate uses
other than bridge or culvert crossings, on -stream structures or dams, all effective designated floodway
conveyance lost due to the project will be replaced for all flood events up to and including the 100-year
frequency flood. In calculating effective designated floodway conveyance, the following factors shall
be taken into consideration-
(i) Designated floodway conveyance, "K" + (1.486/n)(AR2/3) where "n" is Manning's
roughness factor, "A" is the effective flow area of the cross-section, and "R" is the ratio of the area to
the wetted perimeter. (See Ven Te Chow, Open Channel Hydraulics, McGraw-Hill, New York 1959)
(ii) The same Manning's "n" value shall be used for both existing and proposed conditions
unless a recorded maintenance agreement with a federal, state, or local unit of government can assure
the proposed conditions will be maintained or the land cover is changing from a vegetative to a
non -vegetative land cover.
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(iii) Transition sections shall be provided and used in calculations of effi-Ictive designated
floodway conveyance. The following expansion and contraction ratios shall be used unless an
applicant's engineer can prove to IDNR/OWR through engineering calculations or model tests that more
abrupt transitions may be used with the same efficiency:
(1) When water is flowing from a narrow section to a wider section, the water should
be assumed to expand no faster than at a rate of one foot horizontal for every four feet of
the flooded stream's length.
(2) When water is flowing from a wide section to a narrow section, the water should be
assumed to contract no faster than at a rate of one foot horizontal for every one foot of the
flooded stream's length.
(3) When expanding or contracting flows in a vertical direction, a minimum of one
foot vertical transition for every ten feet of stream length shall be used.
(4) Transition sections shall be provided between cross -sections with rapid expansions
and contractions and when meeting the designated floodway delineation on adjacent
properties.
(5) All cross -sections used in the calculations shall be located perpendicular to flood
flows.
(b) Preservation of floodway storage so as not to increase downstream flooding.
(i) Compensatory storage shall be provided for any designated floodway storage lost due to the
proposed work from the volume of fill or structures placed and the impact of any related flood
control projects.
(ii) Compensatory storage for fill or structures shall be equal to at least 1.5 times the volume of
flood plain storage lost.
(iii) Artificially created storage lost due to a reduction in head loss behind a bridge shall not be
required to be replaced.
(iv) The compensatory designated floodway storage shall be placed between the proposed
normal water elevation and the proposed 100-year flood elevation. All designated floodway
storage lost below the existing 10-year flood elevation shall be replaced below the proposed
10-year flood elevation. All designated floodway storage lost above the existing 10-year flood
elevation shall be replaced above the proposed 10-year flood elevation. All such excavations
shall be constructed to drain freely and openly to the watercourse.
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(v) If the compensatory storage will not be placed at the location of the proposed construction,
the applicant's engineer shall demonstrate through a determination of flood discharges and water
surface elevations that the compensatory storage is hydraulically equivalent.
(vi) There shall be no reduction in floodway surface area as a result of a floodway modification,
unless such modification is necessary to reduce at existing structure.
(c) Preservation of floodway velocities so as not to increase stream erosion or flood heights.
For all Appropriate Uses, except bridges or culverts or on -stream structures, the proposed work
will not result in an increase in the average channel or designated floodway velocities or stage, for all
flood events up to and including the 100-year frequency event.
In the case of bridges or culverts or on -stream structures built for the purpose of backing up water
in the stream during normal or flood flows, velocities may be increased at the structure site if scour,
erosion and sedimentation will be avoided by the use of rip -rap or other design measures.
(d) Construction of new bridges or culvert crossings and roadway approaches. The proposed structure
shall not result in an increase of upstream flood stages greater than 0.1 foot when compared to the
existing conditions for all flood events up to and including the 100-year frequency event; or the
upstream flood stage increases will be contained within the channel banks (or within existing vertical
extensions of the channel banks) such as within the design protection grade of existing levees or flood
walls or within recorded flood easements. If the proposed construction will increase upstream flood
stages greater than 0.1 feet, the developer must contact IDNR/OWR to obtain a permit for a dam or
waiver.
(i) The engineering analysis of upstream flood stages must be calculated using the flood study
flows, and corresponding flood elevations for tailwater conditions for the flood study specified in
Section 8-5.0 of this Ordinance. Bridges and culverts must be analyzed using any commonly
accepted FEMA approved hydraulic models
(ii) Lost floodway storage must be compensated for per Section 8-7.5(b).
(iii) Velocity increases must be mitigated per Section 8-7.5(c)
(iv) If the crossing is proposed over a public water that is used for recreational or commercial
navigation, an IDNNR/OWR permit must be received.
(v) The hydraulic analysis for the backwater caused by the bridge showing the existing
condition and proposed regulatory profile must be submitted to IDNR/OWR for concurrence that a
CLOMR is not required by Section 8-7.4.
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(vi) All excavations for the construction of the crossing shall be designed per Section 8-7.5(h).
(e) Reconstruction or modification of existing bridges, culverts, and approach roads.
(i) The bridge or culvert and roadway approach reconstruction or modification shall be
constructed with no more than 0.1 foot increase in backwater over the existing flood profile for all
flood frequencies up to and including the ] 00-year event, if the existing structure is not a source of
flood damage.
(ii) If the existing bridge or culvert and roadway approach is a source of flood damage to
buildings or structures in the upstream flood plain, the applicant's engineer shall evaluate the
feasibility of redesigning the structure to reduce the existing backwater, taking into consideration
the effects on flood stages on upstream and downstream properties.
(iii) The determination as to whether or not the existing crossing is a source of flood damage
and should be redesigned must be prepared in accordance with 17 I11 Adm Code Part 3708
(Floodway Construction in Northeastern Illinois) and submitted to IDNR/OWR for review and
concurrence before a permit is issued.
(f) On -stream structures built for the purpose of backing up water.
Any increase in upstream flood stages greater than 0.0 foot when compared to the existing
conditions, for all flood events up to and including the 100-year frequency event shall be contained
within the channel banks (or within existing vertical extensions of the channel banks) such as within the
design protection grade of existing levees or flood walls or within recorded flood easements.
A permit or letter indicating a permit is not required must be obtained from IDNR/OWR for any
structure built for the purpose of backing up water in the stream during normal or flood flow.
All dams and impoundment structures as defined in Section 8-2.12 shall meet the permitting
requirements of 17 IL Adm. Code Part 3702 (Construction and Maintenance of Dams). If the proposed
activity involves a modification of the channel or floodway to accommodate an impoundment, it shall be
demonstrated that:
(i) The impoundment is determined to be in the public interest by providing flood control,
public recreation, or regional stormwater detention;
(ii) The impoundment will not prevent the migration of indigenous fish species, which require
access to upstream areas as part of their cycle, such as for spawning..
(iii) The impoundment will not cause or contribute to degraded water quality or habitat
conditions. Impoundment design should include gradual bank slopes, appropriate bank
stabilization measures and a pre -sedimentation basin.
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(iv) A non -point source control plan has been implemented in the upstream watershed to
control the effects of sediment runoff as well as minimize the input of nutrients, oil and grease,
metals and other pollutants. If there is more than one municipality in the upstream watershed, the
municipality in which the impoundment is constructed should coordinate with upstream
municipalities to ensure comprehensive watershed control.
(v) The project otherwise complies with the requirements of Section 8-7.0
(g) Flood proofing of existing habitable, residential and commercial structures. If construction is
required beyond the outside dimensions of the existing building, the outside perimeter of the
floodproofing construction shall be placed no further than 10 feet from the outside of the building.
Compensation of lost storage and conveyance will not be required for floodproofing activities.
(h) Excavation in the floodway. When excavation is proposed in the design of bridges and culvert
openings, including the modifications to and replacement of existing bridge and culvert structures, or to
compensate for lost conveyance for other Appropriate Uses, transition sections shall be provided for the
excavation. The following expansion and contraction ratios shall be used unless an applicant's engineer
can prove to IDNR/OWR through engineering calculations or model tests that more abrupt transitions
may be used with the same efficiency:
(i) When water is flowing from a narrow section to a wider section, the water should be
assumed to expand no faster than at a rate of one foot horizontal for every four feet of the flooded
stream's length;
(ii) When water is flowing from a wide section to a narrow section, the water should be
assumed to contract no faster than at a rate of one foot horizontal for every one foot of the flooded
stream's length; and
(iii) When expanding or contracting flows in a vertical direction, a minimum of one foot
vertical transition for every ten feet of steam length shall be used.
(iv) Erosion/scour protection shall be provided inland upstream and downstream of the
transition sections.
(i). If the proposed activity involves a channel modification, it shall be demonstrated that:
(i) There are no practicable alternatives to the activity which would accomplish its purpose
with less impact to the natural conditions of the body of water affected. Possible alternatives
include levees, bank stabilization, flood proofing of existing structures, removal of structures from
the flood plain, clearing the channel, high flow channel, or the establishment of a stream side
buffer strip or green belt. Channel modification is acceptable if the purpose is to restore natural
conditions and improve water quality and fish and wildlife habitat.
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(ii) Water quality, habitat, and other natural functions would be significantly improved by the
modification and not significant habitat area may be destroyed, or the impacts are offset by the
replacement of an equivalent degree of natural resource values.
(iii) The activity has been planned and designed and will be constructed in a way which will
minimize its adverse impacts on the natural conditions of the body of water affected, consistent
with the following criteria:
(1) The physical characteristics of the modified channel shall match as closely as possible
those of the existing channel in length, cross-section, slope and sinuosity. If the existing
channel has been previously modified, restoration of more natural physical conditions
should be incorporated into channel modification design, where practical.
(2) Hydraulically effective transitions shall be provided at both the upstream and
downstream ends of the project designed such that they will prevent erosion.
(3) One-sided construction of a channel shall be used when feasible. Removal of
streamside (riparian) vegetation should be limited to one side of the channel, where
possible, to preserve the shading and stabilization effects of the vegetation.
(4) Clearing of stabilizing vegetation shall be limited to that which is essential for
construction of the channel.
(5) Channel banks shall be constructed with a side slope no steeper than 3:1 horizontal to
vertical, wherever practicable. Native vegetation and gradual side slopes are the preferred
methods for bank stabilization. Where high velocities or sharp bends necessitate the use of
alternative stabilization measures, soil bio-engineering techniques, natural rock or rip -rap
are preferred approaches. Artificial materials such as concrete, gabions, or construction
rubble should be avoided unless there are no practicable alternatives.
(6) All disturbed areas associated with the modification shall be seeded or otherwise
stabilized as soon as possible upon completion of construction. Erosion blanket or an
equivalent material shall be required to stabilize disturbed channel banks prior to
establishment of the vegetative cover.
(7) If the existing channel contains considerable bottom diversity such as deep pools, riffles
and other similar features, such features shall be provided in the new channel. Spawning
and nesting areas and flow characteristics compatible with fish habitat shall also be
established, where appropriate.
(8) A sediment basin shall be installed at the downstream end of the modification to reduce
sedimentation and degradation of downstream water quality.
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(9) New or relocated channels should be built in the dry, and all items of construction,
including vegetation, should be completed prior to diversion of water into the new channel.
(10) There shall be no increases in stage or velocity as the channel enters or leaves the
project site for any frequency flood unless necessitated by a public flood control project or
unless such an increase is justified as part of a habitat improvement or erosion control
project.
(11) Unless the modification is for a public flood control project, there shall be no
reduction in the volume of floodwater storage outside the floodway as a result of the
modification; and
(iv) The project otherwise complies with the requirements of Section 8-7.0.
0) Seeding and stabilization plan. For all activities located in a floodway, a seeding and stabilization
plan shall be submitted by the applicant.
(k) Soil erosion and sedimentation measures. For all activities in the floodway, including grading,
filling, and excavation, in which there is potential for erosion of exposed soil, soil erosion and
sedimentation control measures shall be employed consistent with the following criteria:
(i) The construction area shall be minimized to preserve the maximum vegetation possible.
Construction shall be scheduled to minimize the time soil is exposed and unprotected. In no case
shall the existing natural vegetation be destroyed, removed, or disturbed more than 15 days prior to
the initiation of improvements.
(ii) Temporary and/or permanent soil stabilization shall be applied to denuded areas as soon as
possible. As a minimum, soil stabilization shall be provided within 15 days after final grade is
reached on any portion of the site, and within 15 days to denuded areas which may not be at final
grade but will remain undisturbed for longer than 60 days.
(iii) Sedimentation control measures shall be installed before any significant grading or filling is
initiated on the site to prevent the movement of eroded sediments off site or into the channel.
Potential sediment control devices include filter fences, straw bale fences, check dams, diversion
ditches, and sediment traps and basins.
(iv) A vegetated buffer strip of at least 25 feet in width shall be preserved and/or re-established,
where possible, along existing channels. Construction vehicle use of channels shall be minimized.
Temporary stream crossings shall be constructed where necessary, to minimize erosion. Necessary
construction in or along channels shall be re -stabilized immediately.
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(v) Soil erosion and sedimentation control measures shall be designed and implemented consistent
with "Procedures and Standards for Urban Soil Erosion and Sedimentation Control in Illinois"
(1988) also known as the "Green Book" and "The Illinois Urban Manual" (NRCS, 1995)
(1) Public flood control projects. For public flood control projects, the permitting requirements of this
section will be considered met if the applicant can demonstrate to IDNR/OWR through hydraulic and
hydrologic calculations that the proposed project will not singularly or cumulatively result in increased
flood heights outside the project right-of-way or easements for all flood events up to and including the
100-year frequency event.
(m) General criteria for analysis of flood elevations:
(i) The flood profiles, flows and floodway data in the designated floodway study, referenced in
Section 8-5.0, must be used for analysis of the base conditions. If the study data appears to be in
error or conditions have changed, IDNR/OWR shall be contacted for approval and concurrence on
the appropriate base conditions data to use.
(ii) If the 100-year designated floodway elevation at the site of the proposed construction is
affected by backwater from a downstream receiving stream with a larger drainage area, the
proposed construction shall be shown to meet the requirements of this section for the 100-year
frequency flood elevations of the designated floodway conditions and conditions with the
receiving stream at normal water elevations.
(iii) If the applicant learns from IDNR/OWR, local governments, or a private owner that a
downstream restrictive bridge or culvert is scheduled to be removed, reconstructed, modified, or a
regional flood control project is scheduled to be built, removed, constructed or modified within the
next five years, the proposed construction shall be analyzed and shown to meet the requirements of
this section for both the existing conditions and the expected flood profile conditions when the
bridge, culvert or flood control project is built.
(n)Conditional Letter of Map Revision.
(i) If the Appropriate Use would result in a change in the designated floodway location or the
100-year frequency flood elevation, the applicant shall submit to IDNR/OWR and to FEMA all the
information, calculations and documents necessary to be issued a conditional designated floodway
map revision and receive from IDNR/OWR a conditional concurrence of the designated floodway
change before a permit is issued.
(ii) The final designated floodway map will not be changed by FEMA until as -built plans or record
drawings of initial filling, grading, dredging, or excavating activities are submitted and accepted
by FEMA and IDNR/OWR.
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(iii) In the case of non -government projects, the municipality in incorporated areas and the county
in unincorporated areas shall concur with the proposed conditional designated floodway map
revision before IDNR/OWR approval can be given.
(iv) No filling, grading, dredging or excavating shall take place until a conditional approval is
issued.
(v) After initial filling, grading, dredging, or excavating, no activities shall take place until a final
Letter of Map Revision (LOMR) is issued by FEMA with concurrence from IDNR/OWR.
(o) Professional engineer's supervision. All engineering analyses shall be performed by or under the
supervision of a registered professional engineer.
(p) For all activities in the floodway involving construction within 25 feet of the channel, the following
criteria shall be met:
(i) A natural vegetation buffer strip shall be preserved within at least 25 feet of the ordinary high
water mark of the channel.
(ii) Where it is impossible to protect this buffer strip during the construction of an Appropriate
Use, a vegetated buffer strip shall be established upon completion of construction.
(q) After receipt of conditional approval of the designated floodway change and issuance of a permit and
a Conditional Letter of Map Revision, construction as necessary to change the designated floodway
designation may proceed but no buildings or structures or other construction that is not an Appropriate
Use may be placed in that area until the designated floodway map is changed and a final Letter of Map
Revision is received. The designated floodway map will be revised upon acceptance; and concurrence
by IDNR/OWR and FEMA of the "as built" plans.
See. 8-7.6 Development Activities in delegated communities requiring state review. For those projects
listed below located in a designated floodway, the following criteria shall be submitted to IDNR/OWR
for their review and concurrence and/or permit prior to the issuance of a permit by a community or
county delegated state permitting authority in the floodway:
(a) An engineer's analysis of the flood profile due to a proposed bridge pursuant to Section 8-7.5(d).
(b) An engineer's determination that an existing bridge or culvert crossing is not a source of flood
damage and the analysis indicating the proposed flood profile, pursuant to Section 8-7.5(e).
(c) Alternative transition sections and hydraulically equivalent storage pursuant to Section 8-7.5 (a, b
and h).
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(d) The construction of any IDNR/OWR projects, dams (as defined in Section 8-2.12) and all other state,
federal or local units of government projects, including projects of the municipality or county.
(e) An engineer's determination that a proposed bridge affected by backwater from a downstream
receiving stream may be built with a smaller opening.
(f) Projects which revise or establish the floodway and/or flood profiles.
(g) Projects in public bodies of water.
Sec. 8-7.7 Other permits.
(a) In addition to the other requirements of this ordinance, a development permit for a site located in a
floodway shall not be issued unless the applicant first obtains a permit or written documentation that a
permit is not required from IDNR/OWR, issued pursuant to 615 ILCS 5/5 et seq.
(b) No correspondence from IDNR/OWR shall be required if the project meets the requirements of
Regional Permit 3.
(c) No permit from IDNR/OWR shall be required if IDNR/OWR has delegated this responsibility to the
City.
Sec. 8-7.8 Permits for Dams.
(a) Any work involving the construction, modification or removal of a dam as defined in Section 8-2.12
per 17 IL Adm Code Part 3702(Rules for Construction of Dams) shall obtain an IDNR/OWR permit
prior to the start of construction of a dam.
(b) If the Building Officer finds a dam that does not have an IDNR/OWR permit, the Building Officer
shall immediately notify the IDNR/OWR Bartlett Office.
(c) If the Building Officer finds a dam which is believed to be in unsafe condition, the Building Officer
shall immediately notify the owner of the dam, IDNR/OWR Bartlett Office, and the Illinois Emergency
Management Agency (IEMA).
Sec. 8-7.9 Activities that do not require a registered professional engineer's review. The following
activities may be permitted without a registered professional engineers review. Such activities shall still
meet the other requirements of this ordinance, including the mitigation requirements.
(a) Regional Permit 3 which authorizes, for example, underground and overhead utilities, storm and
sanitary sewer outfalls, sidewalks, patios, athletic fields, playground equipment and streambank
protection activities.
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Sec. 8-8.0 Occupation and use of SFHA areas where floodways are not identified.
In SFHA or flood plains, (including AE Zones, AH Zones, AO Zones, and Un-numbered A
Zones) where no floodways have been identified and no base flood or 100-year frequency flood
elevations have been established by FEMA, and draining more than a square mile, no development shall
be permitted unless the cumulative effect of the proposals, when combined with all other existing and
anticipated uses and structures, shall not significantly impede or increase the flow and passage of the
floodwaters nor significantly increase the base flood or 100-year frequency flood elevation.
Sec. 8-8.1 Development permit. No person, firm, corporation, or governmental body;, not exempted by
state law, shall commence any development in a SFHA or flood plain without first obtaining a
development permit from the Building Officer. Application for a development permit shall be made on
a form provided by the Building Officer. The application shall be accompanied by drawings of the site,
drawn to scale showing property line dimensions; and existing grade elevations and all changes in grade
resulting from excavation or filling, sealed by a licensed engineer, architect or surveyor; the location and
dimensions of all buildings and additions to buildings; and the elevation of the lowest floor (including
basement) of all proposed buildings subject to the requirements of Section 8-9.0 of this Ordinance.
The application for a development permit shall also include the following information:
(a) A detailed description of the proposed activity, its purpose, and intended use;
(b) Site location (including legal description) of the property, drawn to scale, on the designated
floodway maps, indicating whether it is proposed to be in an incorporated or unincorporated area;
(c) Anticipated dates of initiation and completion of activity;
(d) Plans of the proposed activity shall be provided which include as a minimum:
(i) A vicinity map showing the site of the activity, name of the waterway, boundary I ines, names of
roads in the vicinity of the site, graphic or numerical scale, and north arrow;
(ii) A plan view of the project and engineering study reach showing existing and proposed
conditions including principal dimensions of the structure or work, elevations using the North
American Vertical Datum of 1988, adjacent property lines and ownership, drainage and flood
control easements, distance between proposed activity and navigation channel (when the proposed
construction is in or near a commercially navigable body of water), flood plain limit, location and
orientation of cross -sections, north arrow, and a graphical or numerical scale;
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(iii) Cross-section views of the project perpendicular to the flow of floodwater and engineering
study reach showing existing and proposed conditions including principal dimensions of the work
as shown in plan view, existing and proposed elevations, normal water elevation, 10-year
frequency flood elevation, 100-year frequency flood elevation, and graphical or numerical scales
(horizontal and vertical); and
(iv) A soil erosion and sedimentation control plan for disturbed areas. This plan shall include a
description of the sequence of grading activities and the temporary sediment and erosion control
measures to be implemented to mitigate their effects. This plan shall also include a description of
final stabilization and revegetation measures, and the identification of a responsible party to ensure
post -construction maintenance.
(e) Engineering calculations and supporting data shall be submitted showing that the proposed work will
meet the criteria of Section 8-8.4.
(f) Any and all other local, state and federal permits or approvals that may be required for this type of
development.
See. 8-8.2 Based on the best available existing data according to federal, state or other sources, the
Building Officer shall compare the elevation of the site to the base flood or 100-Year frequency flood
elevation.
(a) Should no elevation information exist for the site, the developer's engineer shall calculate the
elevation according to Section 8-5.4.
(b) Any development located on land that can be shown to have been higher than the base flood
elevation of the current Flood Insurance Rate Map identification is not in the SFHA and, therefore, not
subject to the requirements of this ordinance.
(c) The Building Officer shall maintain documentation of the existing ground elevation at the
development site and certification that this ground elevation existed prior to the date of the site's first
Flood Insurance Rate Map identification.
(d) The Building Officer shall be responsible for obtaining from the applicant copies of all other federal,
state and local permits, approvals, or waivers that may be required for this type of activity. The Building
Officer shall not issue the development permit unless all required federal, state, and local permits have
been obtained.
Sec. 8-8.3 Reserved
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Sec. 8-8.4 Preventing increased damages. No development in the SFHA, where a floodway has not
been determined shall create a damaging or potentially damaging increase in flood heights or velocity or
threat to public health, safety and welfare or impair the natural hydrologic and hydraulic firnctions of the
floodway or channel, or impair existing water quality or aquatic habitat. Construction impacts shall be
minimized by appropriate mitigation methods as called for in this ordinance.
Sec. 8-8.5 Within all riverine SFHA's where the floodway has not been determined, the following
standards shall apply:
(a) The developer shall have a Registered Professional Engineer state in writing and show through
supporting plans, calculations and data that the project meets the engineering requirements of Section 8-
7.5(a) through (1) for the entire flood plain as calculated under the provisions of Section 8-5.4 of this
Ordinance.
(i) As an alternative, the developer should have an engineering study performed to determine a
floodway and submit that engineering study to IDNR/OWR and FEMA for acceptance as a
designated floodway.
(ii) Upon acceptance of the floodway by IDNR/OWR and FEMA, the developer shall then
demonstrate that the project meets the requirements of Section 8-7.0 for the designated floodway.
The floodway shall be defined according to the definition in Section 8-2.41 of this Ordinance.
(b) A development permit shall not be issued unless the applicant first obtains an IDNR/OWR permit or
a determination has been made that an IDNR/OWR permit is not required.
(c) Permits for Dams.
(i) Any work involving the construction, modification or removal of a dam as defined in Section 8-
2 II Adm Code Part 3702 (Rules for Construction of Dams) shall obtain an IDNR/OWR permit
prior to the start of construction of a dam.
(ii) If the Building Officer finds a dam that does not have an IDNR/OWR permit, the Building
Officer shall immediately notify the IDNR/OWR Bartlett office.
(iii) If the Building Officer finds a dam which is believed to be unsafe condition, the Building
Officer shall immediately notify the owner of the dam, the IDNR/OWR Bartlett office, and the
Illinois Emergency Management Agency.
(d) The following activities may be permitted without a Registered Professional Engineer's review or
calculation of a base flood elevation and designated floodway. Such activities shall still meet the other
requirements of this ordinance:
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(i) Bridge and culvert crossings of streams in rural areas meeting conditions of IDNR/OWR
Statewide Permit Number 2
(ii) Barge fleeting facilities meeting conditions of IDNR/OWR Statewide Permit No 3
(iii) Aerial utility crossings meeting conditions of IDNR/OWR Statewide Permit No. 4
(iv) Minor boat docks meeting conditions of IDNR/OWR Statewide Permit No 5
(v) Minor, non -obstructive activities meeting conditions of IDNR/OWR Statewide Permit No 6;
activities (not involving fill or positive change in grade) are covered by this permit.
(vi) Outfall structures and drainage ditch outlets meeting conditions of IDNR/OWR Statewide
Permit No 7
(vii) Underground pipeline and utility crossings meeting the conditions of IDNR/OWR Statewide
Permit No 8
(viii) Bank stabilization projects meeting the conditions of IDNR/OWR Statewide Permit No 9
(ix) Accessory structures and additions to existing residential buildings meeting the conditions of
IDNR/OWR Statewide Permit No 10
(x) Minor maintenance dredging activities meeting conditions of IDNR/OWR Statewide Permit No
11
(xi) Bridge and culvert replacement structures and bridge widenings meeting conditions of
IDNR/OWR Statewide Permit No 12
(xii) Temporary construction activities meeting conditions of IDNR/OWR Statewide Permit No 13
(xiii) Special Uses of Public Waters meeting conditions of IDNR/OWR Statewide Permit No 14
(ix) Any development determined by IDNR/OWR to be located entirely within a flood fringe area
shall be exempt from state floodway permit requirements.
See. 8-8.5a The flood carrying capacity within any altered or relocated watercourse shall be maintained.
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Sec. 8-8.6 Compensatory storage.
(a) Whenever any portion of a flood plain is authorized for use, the volume of space which will be
occupied by the authorized fill or structure below the base flood or 100-year frequency flood elevation
shall be compensated for and balanced by a hydraulically equivalent volume of excavation taken from
below the base flood or 100-year frequency flood elevation.
(b) The excavation volume shall be at least equal to 1.5 times the volume of storage lost due to the fill or
structure.
(c) In the case of streams and watercourses, such excavation shall be made opposite or adjacent to the
areas so filled or occupied.
(d) All flood plain storage lost below the existing 10-year a flood elevation shall be replaced below the
proposed 10-year flood elevation. All flood plain storage lost above the existing 10-year flood elevation
shall be replaced above the proposed 10-year flood elevation. All such excavations shall be constructed
to drain freely and openly to the watercourse.
Sec. 8-9.0 Permitting requirements applicable to all flood plain areas.
In addition to the requirements found in Sections 8-6.0, 8-7.0 and 8-8.0 for development in flood
fringes, designated floodways, and SFHA or flood plains where no floodways have been identified, the
following requirements shall be met.
Sec. 8-9.1 Public health standards.
Sec. 8-9.2 No developments in the SFHA shall include locating or storing chemicals, explosives,
buoyant materials, animal wastes, fertilizers, flammable liquids, pollutants, or other hazardous or toxic
materials below the FPE unless such materials are stored in a floodproofed and anchored storage tank
and certified by a professional engineer or floodproofed building constructed according to the
requirements of section 8-9 of this ordinance
Sec. 8-9.2a Public utilities and facilities such as sewer, gas and electric shall be located and constructed
to minimize or eliminate flood damage.
Sec. 8-9.2b Public sanitary sewer systems and water supply systems shall be located and constructed to
minimize or eliminate infiltration of flood waters into the systems and discharges from the systems into
flood waters.
Sec. 8-9.3 New and replacement water supply systems, wells, sanitary sewer lines and on -site waste
disposal systems may be permitted providing all manholes or other above ground openings located
below the FPE are watertight.
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Sec. 8-9.2c All other activities defined as development shall be designed so as not to alter flood flows or
increase potential flood damages.
Sec. 8-9.4 Carrying capacity and notification. For all projects involving channel modification, fill, or
stream maintenance (including levees), the flood carrying capacity of the watercourse shall be
maintained. In addition, the City shall notify adjacent communities in writing 30 days prior to the
issuance of a permit for the alteration or relocation of the watercourse.
Sec. 8-9.5 Protecting buildings. All buildings located within a 100-year flood plain also known as a
SFHA, shall be protected from flood damage below the flood protection elevation. This building
protection criteria applies to the following situations:
(a)Construction or placement of a new building or alteration or addition to an existing building valued at
more than one thousand dollars ($1,000) or seventy (70) square feet.
(b) Substantial improvements or structural alterations made to an existing building that increase the floor
area by more than 20% or equal or exceed' the market value by fifty percent (50%). Alteration shall be
figured cumulatively subsequently to the adoption of this ordinance. If substantially improved, the
existing structure and the addition must meet the flood protection standards of this section.
(c) Repairs made to a substantially damaged building. These repairs shall be figured cumulatively
subsequent to the adoption of this ordinance. If substantially damaged the entire structure must meet the
flood protection standards of this section.
(d) Installing a manufactured home on a new site or a new manufactured home on an existing site. The
building protection requirements do not apply to returning a manufactured home to the same site it
lawfully occupied before it was removed to avoid flood damage
(e) Installing a travel trailer or recreational vehicle on a site for more than 180 days per year; and
(f) Repetitive loss to an existing building as defined in Section 8-2. This building protection requirement
may be met by one of the following methods.
Sec. 8-9.6 A residential or non-residential building, when allowed, may be constructed on permanent
land fill in accordance with the following:
(a) The lowest floor, (including basement) shall be at or above the flood protection elevation; and
(b) The fill shall be placed in layers no greater than six inches deep before compaction and should
extend at least ten (10) feet beyond the foundation of the building before sloping below the flood
protection elevation; and
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(c) The top of the fill shall be above the flood protection elevation. However, the ten (10) foot minimum
may be waived if a structural engineer certifies an alternative method to protect the building from
damages due to hydrostatic pressures; and
(d) The fill shall be protected against erosion and scour during flooding by vegetative cover, riprap or
other structural measure; and
(e) The fill shall be composed of rock or soil and not incorporate debris or refuse materials; and
(f) The fill shall not adversely affect the flow or surface drainage from or onto neighboring properties,
and when necessary, stormwater management techniques such as swales or basins shall be incorporated.
See. 8-9.7 A residential or non-residential building may be elevated in accordance with the following:
(a) The building or improvements shall be elevated on crawl space, stilts, piles, walls, or other
foundation that is permanently open to flood waters and not subject to damage by hydrostatic pressures
of the base flood or 100-year frequency flood. Designs must either be certified by a registered
professional engineer or architect or the permanent openings, one on each wall, shall be not more than
one foot above existing grade, and consist of a minimum of two openings. The openings must have a
total net area of not less than one square inch for every one square foot of enclosed area subject to
flooding below the Base Flood Elevation; and
(b) The foundation and supporting members shall be anchored and aligned in relation to flood flows and
adjoining structures so as to minimize exposure to known hydrodynamic forces such as current, waves,
ice and floating debris; and
(c) All areas below the flood protection elevation shall be constructed of materials resistant to flood
damage. The lowest floor (including basement) and all electrical, heating, ventilating, plumbing, and air
conditioning equipment and utility meters shall be located at or above the flood protection elevation.
Water and sewer pipes, electrical and telephone lines, submersible pumps, and other waterproofed
service facilities may be located below the flood protection elevation.
(i) The lowest floor (including basement) and all electrical, heating, ventilating, plumbing, and air
conditioning equipment and utility meters shall be located at or above the flood protection
elevation; and
(ii) Water and sewer pipes, electrical and telephone lines, submersible pumps, and other
waterproofed service facilities may be located below the flood protection elevation provided they
are waterproofed; and
(d) The areas below the flood protection elevation may only be used for the parking of vehicles, building
access or storage in an area other than a basement and not later modified or occupied as habitable
space; and
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(e) In lieu of the above criteria, the design methods to comply with these requirements may be certified
by registered professional engineer or architect.
(f) Manufactured homes and travel trailers to be installed on a site for more than 180 days, shall be
elevated to or above the flood protection elevation; and, shall be anchored to resist flotation, collapse, or
lateral movement by being tied down in accordance with the Rules and Regulations for the Illinois
Mobile Home Tie -Down Act issued pursuant to 77 IL Adm. Code Part 870. In addition, all
manufactured homes shall meet the following elevation requirements:
(i) In the case of manufactured homes placed or substantially improved (1) outside of a
manufactured home park or subdivision, (2) in a new manufactured home park or subdivision, (3)
in an expansion to an existing manufactured home park or subdivision, or (4) in an existing
manufactured home park or subdivision on which a manufactured home has incurred substantial
damage from a flood, the top of the lowest floor shall be elevated to or above the flood protection
elevation.
(ii) In the case of manufactured homes placed or substantially improved in an existing
manufactured home park or subdivision, the manufactured home shall be elevated to that either the
top of the lowest floor is above the base flood elevation or the chasis is at least 36 inches in height
above grade and supported by reinforced piers or other foundations of equivalent strength,
whichever is less.
(g) Recreational vehicles or travel trailers shall be required to meet the elevation and anchoring
requirements of Subsection 8-9.7b above unless:
(i) They are on site for fewer than 180 consecutive days; and
(ii) They are fully licensed, ready for highway use, and used only for recreation, camping, travel
or seasonal use rather than as a permanent dwelling. A recreational vehicle is ready for highway
use if it is on its wheels or jacking system, is attached to the site only by quick disconnect type
utility and service devices, and has no permanently attached additions.
Sec. 8-9.8A. Only a non-residential building may be structurally dry floodproofed (in lieu of elevation)
provided that:
(a) A registered professional engineer or architect shall certify that the building has been structurally dry
floodproofed below the flood protection elevation, the structure and attendant utility facilities are
watertight and capable of resisting the effects of the base flood or 100-year frequency flood.
(b) The building design shall take into account flood velocities, duration, rate of rise, hydrostatic and
hydrodynamic forces, the effects of buoyancy, and impacts from debris or ice.
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(c) Floodproofing measures shall be operable without human intervention and without an outside source
of electricity (Levees, berms, floodwalls and similar works are not considered floodproofing for the
purpose of this subsection).
Sec. 8-9.8B A building may be constructed with a crawlspace located below the flood protection
elevation provided that the following conditions are met:
(i) The building must be designed and adequately anchored to resist flotation, collapse, and lateral
movement of the structure resulting from hydrodynamic and hydrostatic loads, including the
effects of buoyancy; and
(ii) Any enclosed area below the flood protection elevation shall have openings that equalize
hydrostatic pressures by allowing for the automatic entry and exit of floodwaters. A minimum of
one opening on each wall having a total net area of not less than one square inch per one square
foot of enclosed area. The openings shall be no more than one (1) foot above grade; and
(iii) The interior grade of the crawlspace below the flood protection elevation must not be more
than two (2) feet below the lowest adjacent exterior grade; and
(iv) The interior height of the crawlspace measured from the interior grade of the crawl to the top
of the foundation wall must not exceed four (4) feet at any point; and
(v) An adequate drainage system must be installed to remove floodwaters from the interior area of
the crawlspace within a reasonable period of time after a flood event; and
(vi) Portions of the building below the flood protection elevation must be constructed with
materials resistant to flood damage; and
(vii) Utility systems within the crawlspace must be elevated above the flood protection elevation.
Sec. 8-9.8C Construction of new or substantially improved critical facilities shall be located outside the
limits of the floodplain. Construction of new critical facilities shall be permissible within the floodplain
if no feasible alternative site is available. Critical facilities constructed within the SFHA shall have the
lowest floor (including basement) elevated or structurally dry floodproofed to the 500-year flood
frequency elevation or three feet above the level of the 100-year flood frequency elevation, whichever is
greater. Floodproofing and sealing measures must be taken to ensure that toxic substances will not be
displaced by or released into floodwaters. Access routs elevated to or above the level of the base flood
elevation shall be provided to all critical facilities.
Sec. 8-9.8D Tool sheds and detached garages and other minor accessory structures on an existing
single-family platted lot, may be constructed with the lowest floor below the flood protection elevation
in accordance with the following:
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(a) The building is not used for human habitation.
(b) All areas below the base flood or 100-year frequency flood elevation shall be constructed with
waterproof material. Structures located in a designated floodway shall be constructed and placed on a
building site so as not to block the flow of flood waters and shall also meet the Appropriate Use criteria
of Section 8-7.0. In addition, all other requirements of Section 8-6, 8-7 and 8-8 must be met.
(c) The structure shall be anchored to prevent flotation.
(d) Service facilities such as electrical and heating equipment shall be elevated or floodproofed to the
flood protection elevation; and
(e) The building shall be valued at less than $10,000 and be less than 500 square feet in floor size; and
(f) The building shall be used only for the storage of vehicles or tools and may not contain other rooms,
workshops, greenhouses or similar uses and cannot be modified later into another use; and
(g) The building shall meet the permanent opening criteria of Section 8-9.7(a);
(h) All flammable or toxic materials (gasoline, paint, insecticides, fertilizers, etc.) shall be stored above
the flood protection elevation; and
(i) The lowest floor elevation should be documented and the owner advised of the flood insurance
implications.
Sec. 8-9.9 Existing buildings located within a designated floodway shall also meet the more restrictive
Appropriate Use standards included in Section 8-7.4. Non -conforming structures located in a designated
floodway may remain in use and may only be enlarged, replaced or structurally altered in accordance
with Section 8-7.5. A non -conforming structure damaged by flood, fire, wind or other natural or man-
made disaster may be restored unless the damage exceeds fifty percent (50%) of its market value before
it was damaged, in which case it shall conform to this ordinance.
Sec. 8-10.0 Other development requirements.
The City Council shall take into account flood hazards, to the extent that they are known in all official
actions related to land management, use and development.
Sec. 8-10.1 New subdivisions, manufactured home parks, annexation agreements, and Integrated
Development Districts (IDDs) within the SFHA shall be reviewed to assure that the proposed
developments are consistent with Sections 8-6.0, 8-7.0, 8-8.0 and 8-9.0 of this ordinance and the need to
minimize flood damage. Plats or plans for new subdivisions, manufactured home parks and IDD's shall
include a signed statement by a Registered Professional Engineer that the plat or plans account for
changes in the drainage of surface waters in accordance with the Plat Act (765 ILCS 205/2).
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Sec. 8-10.2 Proposals for new subdivisions, manufactured home parks, travel trailer parks, IDD's and
additions to manufactured home parks and additions to subdivisions shall include base flood or 100-year
frequency flood elevation data and floodway delineations.
(a) Where this information is not available from an existing adopted study, the applicant's engineer shall
be responsible for calculating the base flood or 100-year frequency flood elevation per Section 8-5.4 and
the floodway delineation per the definition in Section 8-2.41.
Sec. 8-10.3 Streets, blocks, lots, parks and other public grounds shall be located and laid out in such a
manner as to preserve and utilize natural streams and channels. Wherever possible, the flood plains
shall be included within parks or other public grounds.
Sec. 8-10.4 The City Council shall not approve any IDD or plat of subdivision located outside the
corporate limits unless such agreement or plat is in accordance with the provisions of this ordinance.
Sec. 8-11.0 All other activities defined as development shall be designed so as not to alter flood flows or
increase potential flood damages.
Sec.8-11.1 Variances.
No variances shall be granted to any development located within a designated floodway as defined in
Section 8.2.12a.
(a) Whenever the standards of this ordinance place undue hardship on a specific development proposal,
the applicant may apply to the City Council for a variance.
(b) The City Council shall review the applicant's request for a variance and shall submit its
recommendation to the City Council. The City may attach such conditions to granting a variance as it
deems necessary to further the flood protection intent of this ordinance.
Sec. 8-11.2 No variance shall be granted unless the applicant demonstrates that all of the following
conditions are met:
(a) The development activity cannot be located outside the SFHA; and
(b) An exceptional hardship would result if the variance were not granted; and
(c) The relief requested is the minimum necessary; and
(d) There will be no additional threat to public health, safety, beneficial stream uses and functions,
especially aquatic habitat, or creation of a nuisance; and
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(e) There will be no additional public expense for flood protection, lost environmental stream uses and
functions, rescue or relief operations, policing, or repairs to streambeds and banks, roads, utilities, or
other public facilities; and
(f) The provisions of Sections 8-6 and 8-8 of this ordinance shall still be met;
(g) The activity is not in a designated floodway; and
(h) The applicant's circumstances are unique and do not establish a pattern inconsistent with the intent
of the NFIP; and
(i) The granting of the variance will not alter the essential character of the area involved including
existing stream uses; and
0) All other required state and federal permits or waivers have been obtained.
Sec. 8-11.3 The Building Officer shall notify an applicant in writing that a variance from the
requirements of Section 8-9.0 that would lessen the degree of protection to a building will:
(a) Result in increased premium rates for flood insurance up to amounts as high as $25 for $100 of
insurance coverage; and
(b) Increase the risks to life and property; and
(c) Require that the applicant proceed with knowledge of these risks and that the applicant will
acknowledge in writing that he assumes the risk and liability.
Sec. 8-11.4 Variances requested in connection with restoration of an historic site or historic structure as
defined in Subsection 8-2-27.1, Historic Structures, may be granted using criteria more permissive than
the requirements of Section 8-11.1 and 8-11.2, subject to the conditions that:
(a) The repair or rehabilitation is the minimum necessary to preserve the historic character and design of
the structure; and,
(b) The repair or rehabilitation will not result in the structure being removed as a certified historic
structure.
Sec. 8-12.0 Disclaimer of liability.
The degree of flood protection required by this ordinance is considered reasonable for regulatory
purposes and is based on available information derived from engineering and scientific methods of
study. Larger floods may occur or flood heights may be increased by man-made or natural causes.
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This ordinance does not imply that development, either inside or outside of the SFHA, will be free from
flooding or damage.
This ordinance does not create liability on the part of the City, or any officer or employee thereof for any
flood damage that results from reliance on this ordinance or any administrative decision made lawfully
thereunder.
Sec. 8-13.0. Penalty.
If such owner fails after ten days notice to correct the violation:
(a) The City may make application to the Circuit Court of McHenry County, Illinois for an injunction
requiring conformance with this ordinance or make such other order as the Court deems necessary to
secure compliance with the ordinance.
(b) Any person who violates this Ordinance shall, upon conviction thereof, be fined not less than Fifty
Dollars ($50.00) or more than One -Thousand Dollars ($1,000.00) for each offense.
(c) A separate offense shall be deemed committed upon each day during or on which a violation occurs
or continues.
(d) The City shall record a notice of violation on the title to the property.
Sec. 8-13.1 The Building Officer shall inform the owner that any such violation is considered a willful
act to increase flood damages and, therefore, may cause coverage by a Standard Flood Insurance Policy
to be suspended.
(a) The Building Officer is authorized to issue an order requiring suspension of the subject development.
The stop -work order shall be in writing, shall indicate the reason for the issuance, and shall order the
action, if necessary, to resolve the circumstances requiring the stop -work order. The stop -work order
constitutes a suspension of the permit.
(b) No site development permit shall be permanently suspended to revoked until a hearing is held by the
City Council. Written notice of such hearing shall be served on the permittee and shall state:
(i) the grounds for complaint or reasons for suspension or revocation; and
(ii) the time and place of hearing.
(c) At such hearing, the permittee shall be given an opportunity to present evidence on his/her behalf.
(d) At the conclusion of the hearing, the City Council shall determine whether the permit shall be
suspended or revoked.
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Sec. 8-13.3 Nothing herein shall prevent the City from taking such other lawful action to prevent or
remedy any violations. All costs connected therewith shall accrue to the person or persons responsible.
Sec. 8-14.0 Abrogation and greater restrictions.
This ordinance is not intended to repeal, abrogate or impair any existing easements, covenants, or deed
restrictions. Where this ordinance and other ordinance, easements, covenants, or deed restrictions
conflict or overlap, whichever imposes the more stringent restrictions shall prevail.
This Ordinance is intended to repeal the original ordinance or resolution which was adopted to meet the
National Flood Insurance Program regulations, but is not intended to repeal the resolution which the
City passed in order to establish initial eligibility for the program.
Sec.8-15.0 Separability.
The provisions and sections of this ordinance shall be deemed separable and the invalidity of any portion
of this ordinance shall not affect the validity of the remainder.
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SECTION 2: If any section, paragraph, subdivision, clause, sentence or provision
of this ordinance shall be adjudged by any Court of competent jurisdiction to be invalid,
such judgment shall not affect, impair, invalidate or nullify the remainder thereof, which
remainder shall remain and continue in full force and effect.
Section 3: All ordinances or parts thereof in conflict are hereby repealed to the
extend of such conflict.
Section 4: This ordinance shall be in full force and effect upon its passage,
approval and publication in pamphlet form as provided by law.
Voting Aye:
Santi, Glab, Schaefer, Murgatroyd, Wimmer, Peterson, Condon.
Voting Nay:
None.
Not Voting:
None.
Abstaining:
None.
Absent:
None.
Passed and Approved this 6 h day of November, 2006
APPROVED.
a —
Mayor
i tie. C. ntb�
ATTEST:----------- --- ---------- 0- ------------------------
City Clerk