HomeMy WebLinkAboutORDINANCE - 3179 - 7/15/2008 - DEVELOPMENT IN SPECIAL FLOOD HAZARD AREAS (Rescinding Ord. 2785)ORDINANCE NO. 3179
AN ORDINANCE ADOPTING REGULATIONS FOR DEVELOPMENT IN
SPECIAL FLOOD HAZARD AREAS AND RESCINDING ORDINANCE NO.
2785 WHICH ESTABLISHED AND AMENDED THE FLOODPLAIN
REGULATIONS OF THE VILLAGE OF ELK GROVE VILLAGE
NOW, THEREFORE, BE IT ORDAINED by the Mayor and Board of Trustees of
the Village of Elk Grove Village, Cook and DuPage Counties, Illinois:
Section 1: That Ordinance No. 2785 Regulations for Development in Special
Flood Hazard Areas, duly passed and approved by the Mayor and Board of Trustees on
October 24, 2000 is hereby repealed:
Section 2: That Regulations for Development in Special Flood Hazard Areas
of the Village of Elk Grove Village be adopted as follows:
SECTION
8-11-1:
Purpose
8-11-2:
Definitions
8-11-3:
How to Use This Ordinance
8-11-4:
Duties of Enforcement Official
8-11-5:
Base flood Elevation
8-11-6:
Occupation and Use of Flood Fringe Areas
8-11-7:
Occupation and Use of Designated Floodways
8-11-8:
Occupation and Use of Special Flood Hazard
Areas Where Floodways Are Not Identified
8-11-9:
Permitting Requirements Applicable to All
Floodplain Areas and Protection of Buildings
8-11 A 0:
Other Development Requirements
8-11-11:
Variances
8-11-12:
Disclaimer of Liability
8-11-13:
Penalty
8-11-14:
Abrogation and Greater Restrictions
8-11-15:
Severability
8-11-16:
Effective Date
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8-11-1 Purpose
This Ordinance is enacted pursuant to the police powers granted to the Village of Elk Grove
Village 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 Elk Grove Village'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:
A. To meet the requirements of 615 ILCS 5/18(g) Rivers, Lakes and Streams Act;
B. To assure that new development does not increase the flood or drainage hazards
to others, or creating unstable conditions susceptible to erosion;
C. To protect new buildings and major improvements to buildings from flood
damage;
D. To protect human life and health from the hazards of flooding;
E. 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; and
F. To make federally subsidized flood insurance available for property in the
. Village by fulfilling the requirements of the National Flood Insurance Program;
G. To comply with the rules and -regulations of the National Flood Insurance
Program codified as 44 CFR 59-79, as amended.
H. To protect, conserve, and promote the orderly development of land and water
resources; and
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.
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8-11-2 Definitions
For the purposes of this Chapter, the following definitions are adopted:
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.
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.
APPLICANT: Any person, firm, corporation or agency which submits an application.
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 8-11-713.
BASE FLOOD: The flood having a one -percent chance of being equaled 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 8-11-5 of this
Ordinance.
BASE FLOOD ELEVATION (BFE): The elevation in relation to mean sea level of the
crest of the base flood.
BASEMENT: That portion of the building having its floor subgrade (below ground level)
on all sides.
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. The term also includes recreational vehicles and travel trailers
installed on a site for more than 180 days per year.
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.
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 involving a significant change in
the channel cross-section and typically involving relocation of the existing channel (e.g.
straightening).
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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 floodplain. The
uncompensated loss of natural floodplain storage can increase off-site floodwater elevations
and flows.
CONDITIONAL APPROVAL OF A DESIGNATED FLOODWAY MAP CHANGE:
Preconstruction approval by IDNWOWR and 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.
CONDITIONAL LETTER OF MAP REVISION (CLOMR): A letter which indicates
that FEMA 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.
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.
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 (chemicals,
petrochemicals, hazardous or toxic substances). Examples of critical facilities where flood
protection is recommended include: sewage treatment plants, water treatment plants, and
pumping stations.
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.
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 stage due to the loss of flood conveyance
or storage, and no more than a 10 percent increase in velocities.
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A. The floodways are designated for on the countywide Flood Insurance Rate Map
of Cook and DuPage Counties prepared by FEMA and dated August 19, 2008
and December 16, 2004. When two floodway maps exist for a waterway, the
more restrictive floodway limit shall prevail.
B. The floodways for those parts of unincorporated Cook and DuPage Counties that
are within the extraterritorial jurisdiction of the Village of Elk Grove Village that
may be annexed into the Village are designated for Salt Creek on the
count},vide Flood Insurance Rate Map prepared by FEMA and dated August
19, 2008 and December 16, 2004.
C. 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.
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 for less than 180
days, it must be fully licensed and ready for highway use.
C. Drilling, mining, installing utilities, construction of roads, bridges, 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,
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plowing, and similar agricultural practices that do not involve filling, grading, or
construction of levees.
ELEVATION CERTIFICATES: A form published by FEMA that is used to certify the
elevation to which a building has been elevated.
EROSION: The general process whereby soils are moved by flowing water or wave
action.
EXEMPT ORGANIZATIONS: Organizations which are exempt from this Ordinance per
Illinois Compiled Statutes (ILCS) including state, federal or local units of government.
EXISTING MANUFACTURED. HOME PARK OR SUBDIVISON: 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.
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).
FEMA: Federal Emergency Management Agency and its regulations at 44 CFR 59-79, as
amended.
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.
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.
FLOOD FRINGE: That portion of the floodplain outside of the designated floodway. See
commentary on "designated floodway':
FLOOD INSURANCE RATE MAPS (FIRM): A map prepared by FEMA that depicts
the Special Flood Hazard Area (SFHA) within a community. This map includes insurance
rate zones and floodplains and may or may not depict floodways.
FLOOD INSURANCE STUDY: An examination, evaluation and determination of flood
hazards and if appropriate, corresponding water surface elevations.
FLOODPLAIN: 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. Floodplains
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may also include detached Special Flood Hazard Areas, ponding areas, etc. The floodplain
is also known as the Special Flood Hazard Area (SFHA).
A. The floodplains are those lands within the jurisdiction of the Village of Elk
Grove Village that are subject to inundation by the base flood or 100 -year
frequency flood. The SFHAs of the Village of Elk Grove Village are generally
identified as such on panel numbers 0193, 0194, 0211, 0213, 0214, 0216, 0218,
0331, 0332, 0351; and 302, 303 of the countywide Flood Insurance Rate Map of
the Village prepared by the Federal Emergency Management Agency and dated
August 19, 2008 and December 16, 2004.
B. The SFHAs of those parts of unincorporated Cook and DuPage Counties that are
within the extraterritorial jurisdiction of the Village of Elk Grove Village or that
may be annexed into the Village are generally identified as such on panel
numbers 0193, 0194, 0211, 0213, 0214, 0216, 0218, 0331, 0332, 0351; and 302,
303 of the county ride Flood Insurance Rate Map prepared for Cook and
DuPage Counties by the Federal Emergency Management Agency and dated
August 19, 2008 and December 16, 2004.
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.
FLOODPROOFING CERTIFICATE: A form published by FEMA that is used to certify
that a building has been designed and constructed to be structurally dry floodproofed to the
flood protection elevation.
FLOOD PROTECTION ELEVATION (FPE): The elevation of the base flood or 100 -
year frequency floods plus onefoot offreeboard at any given location in the SFHA.
FLOODWAY: See Designated Floodway.
HISTORIC STRUCTURE: Any structure that is:
A. Listed individually in the National Register of Historic Places or preliminary
determined by the Secretary of the Interior as meeting the requirements for
individual listing on the National Register;
B. Certified or preliminary determined by the Secretary of the Interior as
contributing to the historic district or a district preliminary determined by the
Secretary to qualify as a registered historic district;
C. Individually listed on the State inventory of historic places 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.
HYDROLOGIC AND HYDRAULIC CALCULATIONS: Engineering analysis which
determine expected flood flows and flood elevations based on land characteristics and
rainfall events.
IDNR/OWR: Illinois Department of Natural Resources, Office of Water Resources.
LETTER OF MAP AMENDMENT (LOMA): Official determination by FEMA that a
specific structure is not in a 100 -year floodplain; amends the FIRM.
LETTER OF MAP REVISION (LOMR): Letter that revises base flood or 100 -year
frequency flood elevations, floodplains or floodways as shown on an effective FIRM.
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 buildings 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.
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 attached 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''.
MANUFACTURED HOME PARK OR SUBDIVISION: A parcel (or contiguous
parcels) of land divided into two or more manufactured home lots for rent or sale.
MITIGATION: Mitigation includes those measures necessary to minimize the negative
effects which floodplain 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.
NEW CONSTRUCTION: New construction means structures for, which the start of
construction commenced on or after the effective date of a floodplain management
regulation adopted by a community and includes any subsequent improvements to such
structures.
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,
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the construction of streets, and either final site grading or the pouring of concrete pads) has
been completed on or after April 1, 1990.
NAVD 88: National American Vertical Datum of 1988. NAVD 88 supersedes the National
Geodetic Vertical Datum of 1929 (NGVD).
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 floodplain 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 or 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 regrading
and revegetation.
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.
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, including 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.
PUBLIC BODIES OF WATERS: 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.
RECREATION VEHICLE OR TRAVEL TRAILER: A vehicle which is:
A. Built on a single chassis;
B. 400 square feet or less when measured at the largest horizontal projection;
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.
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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 regulatory floodways. A complete listing of the terms and conditions
for specific project types can be obtained from the IDNR/OWR website.
REGISTERED LAND SURVEYOR: A land surveyor registered in the State of Illinois,
under The Illinois Land Surveyors Act. (225 ILCS 330/1, et seq.)
REGISTERED OR LICENSED PROFESSIONAL ENGINEER: An engineer
registered in the State of Illinois, under The Illinois Professional Engineering Practice Act.
(225 ILCS 325/1 et seq.)
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.
REPETITIVE LOSS: Flood -related damages sustained by a structure on two separate
occasions during a 10 -year period for which the cost of repairs at the time of each such flood
event, on the average, equals or exceeds 25 percent of the market value of the structure
before the damaged occurred.
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.
RIVERINE SFHA: Any SFHA subject to flooding from a river, creek, intermittent stream,
ditch, on -stream lake system or any other identified channel. This term does not include
areas subject to flooding from lakes, ponding areas; areas of sheet flow, or other areas not
subject to overbank flooding.
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.
SEDIMENTATION: The processes that deposit soils, debris, and other materials either on
other ground surfaces or in bodies of water or watercourses.
SPECIAL FLOOD HAZARD AREA(SFHA): See "Floodplain".
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.
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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.
STRUCTURE: See "'Building".
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. The term- includes Repetitive Loss Buildings See
"Repetitive Loss".
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 improvements equals or exceeds 50 percent of the
market value of the structure before the improvement or repair is started.
A. "Substantial Improvement" is considered to occur when the first alteration of any
wall, ceiling, floor, or other structural part of the building commences, whether
or not that alteration affects the external dimensions of the building. This term
includes structures which have incurred repetitive loss or substantial damage,
regardless of the actual work done.
B. The term does not, however, include either:
1. 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
2. any alteration of a "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 a historic
structure.
TRANSITION SECTION: Reaches of the stream or floodway where water flows from a
narrow cross-section to a wide cross-section or vice versa.
- VIOLATION: The failure of a structure or other development to be fully compliant with
the community's floodplain management regulations. A structure or other development
without the elevation certificate, other certifications, or other evidence of compliance is
presumed to be in violation until such time as that documentation is provided.
8-11-3 How to Use This Ordinance
The Director of Engineering & Community Development shall be responsible for fulfilling
all of the duties listed in Section 8-114 of this Chapter
To fulfill those duties, the Director of Engineering & Community Development should first
use the criteria listed in Section 8-11-5, 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 floodplain, the Director of
Engineering & Community Development must determine whether the. development site is
within a flood fringe, a designated floodway, or within a SFHA or floodplain for which no
floodway has been identified.
If the site is within a flood fringe, the Director of Engineering & Community Development
shall require that the minimum requirements of Section 8-11-6 be met.
If the site is within a floodway, the Director of Engineering & Community Development
shall require that the minimum requirements of Section 8-11-7 be met.
If the site is located within a SFHA or floodplain for which no detailed study has been
completed and approved, the Director of Engineering & Community Development shall
require that the minimum requirements of Section 8-11-8 be met.
In addition, the general requirements of Section 8-11-9 shall be'met for all developments
meeting the requirements of Section 8-11-6, 8-11-7, or 8-11-8.
The Director of Engineering & Community Development shall assure that all subdivision
proposals shall meet the requirements of Section 8-11-10.
If a variance is to be granted for a proposal, the Director of Engineering & Community
Development shall review the requirements of Section 8-11-11 to make sure they are met.
In addition, the Director of Engineering & Community Development shall complete all
notification requirements.
In order to assure that property owners obtain permits as required in this Ordinance, the
Director of Engineering & Community Development may take any and all actions as
outlined in Section 8-11-13.
8-11-4 Duties of the Director of Engineering & Community Development
A. Determining the Floodplain Designation.
1. Check all new development sites to determine whether they are in a Special
Flood Hazard Area (SFHA).
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2. If they are in a SFHA, determine whether they are in a floodway, flood
fringe or in a floodplain for which a detailed study has not been conducted
and which drains more than one (1) square mile.
3. 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.
B. Professional Engineer Review.
If the development site is within a floodway or in a floodplain for which a
detailed study has not been conducted and which drains more than one
square mile, the permit shall be referred to a licensed professional engineer
under the employ or contract of the Village for review to ensure that the
development meets Sections 8-11-7 or 8-11-8.
2. In the case of an Appropriate Use, the P.E. shall state in writing that the
development meets the requirements of Section 8-11-7.
C. Dam Safety. Requirements.
1. Dams are classified as to their size and their hazard/damage potential in the
event of failure.
2. The construction or major modification of all Class I (high hazard) and Class
II (moderate hazard) dams require an IDNR/OWR dam safety permit.
3. 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 dam.
It is not required that IDNR/OWR "sign off' on all non -jurisdictional
Class III dams.
4. A consulting engineer with dam safety knowledge can estimate a hazard
classification and determine if an IDNR/OWR dam safety permit is required.
5. A permit application submittal must be made to IDNR/OWR for the
construction or major modification of jurisdictional dams.
6. Regulated dams may include weirs, restrictive culverts or impoundment
structures.
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D. Other permit requirements.
Ensure any and all required federal, state and local permits are received prior to
the issuance of a floodplain development permit.
E. Plan Review and Permit Issuance.
1. Ensure that all development activities within the SFHAs of the jurisdiction of
the Village of Elk Grove Village meet the requirements of this Ordinance,
and;
2. Issue a floodplain 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.
F. Inspection Review.
1. Inspect all development projects before, during and after construction to
assure proper elevation of the structure and to ensure compliance with the
provisions of this Ordinance; and
2. Schedule on an annual basis an inspection of the floodplain and
document the results of the inspection.
G. 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 8-11-9.C.3.
H. Elevation and Floodproofing Certificates.
Maintain permit files including:
1. An Elevation Certificate certifying the elevation of the lowest floor
(including basement) of a residential or non-residential building subject to
Section 8-11-9 of this Ordinance, and/or;
2. The elevation to which a non-residential building has been floodproofed,
using a Floodproofing Certificate, for all buildings subject to Section 8-11-9
of this Ordinance.
I. Records for Public Inspection.
Maintain for public inspection and furnish upon request base flood data, SFHA
and designated floodway maps, copies of federal or state permit documents,
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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.
J. State Permits.
Ensure that construction authorization has been granted by IDNR/OWR, for all
development projects subject to Sections 8-11-7 and 8-11-8 of this Ordinance,
unless enforcement responsibility has been delegated to the Village of Elk
Grove Village. However, the following review approvals are not delegated to
the Village of Elk Grove Village and shall require review or permits from
IDNR/OWR:
1. Organizations which are exempt from this Ordinance, as per the Illinois
Compiled Statutes;
2. IDNR/OWR projects, dams or impoundment structures as defined in Section
8-11-2 and all other state, federal or local unit of government projects,
including projects of the Village of Elk Grove Village and County, except
for those projects meeting the requirements of Subsection 8-11-7137;
3. 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 Subsection 8-11-713-3d;
4. An engineer's analysis of the flood profile due to Subsection 8-11-713-3d;
5. Alternative transition sections and hydraulically equivalent compensatory
storage as indicated in Subsection 8-11-713-3a, b & h;
6. Permit issuance of structures within, under, or over publicly navigable rivers,
lakes and streams;
7. Any changes in the mapped floodway or published flood profiles. .
K. Cooperation with Other Agencies.
1. Cooperate with state and federal floodplain management agencies to
improve base flood or 100 -year frequency flood and floodway data and to
improve the administration of this Ordinance;
2. Submit data to IDNR/OWR and FEMA for proposed revisions of a
regulatory map within 6 months whenever a modification of the floodplain
may change the base flood elevation or result in a change to the floodplain
map;
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3. Submit reports as required for the National Flood Insurance Program; and
4. Notify FEMA of any proposed amendments to this Ordinance.
L. 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.
8-11-5 Base Flood Elevation
This Ordinance's protection standard is based on the Flood Insurance Study for the
Village of.Elk Grove Village. 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
IDNRIOWR and FEMA for review and consideration prior to any development of
the site.
A. The base flood or 100 -year frequency flood elevation for the SFHAs of Salt
Creek, the Elk Grove Boulevard Drainage Ditch, the Unnamed Creek, the West
Branch of Salt Creek, and the tributary to the West Branch of Salt Creek shall be
as delineated on the 100 -year flood profiles in the Flood Insurance Study of the
Cook County prepared by FEMA dated August 19; 2008 and for the DuPage
County portions of the Village, the 100 -year profiles are shown in the DuPage
County Flood Insurance Study dated December 16, 2004, and such amendments
to such study and maps as may be prepared from time to time.
B. The base flood or 100 -year frequency flood elevation for the SFHAs of those
parts of unincorporated Cook and DuPage Counties that are within the
extraterritorial jurisdiction of the Village of Elk Grove Village or that may be
annexed into the Village shall be as delineated on the 100 -year flood profiles in
the Flood Insurance Study of Cook and DuPage Counties prepared by FEMA
and dated August 19, 2008 and December 16, 2004 and such amendments or
revisions to such study and maps as may be prepared from time to time.
C. 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 countywide Flood Insurance Rate Map of Cook and DuPage Counties.
D. The base flood or 100 -year frequency flood elevation for each of the remaining
SFHAs delineated as an "A Zone" on the countywide Flood Insurance Rate Map
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of Cook and DuPage Counties 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.
1. 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 -II, HEC -RAS, or a
dynamic model such as HIP.
2. The flood flows used in the hydraulic models shall be obtained from a
hydrologic model, such as HEC -HMS, HEC -1, TR -20, or HIP, or by
techniques presented in various publications prepared by the United States
Geological Survey for estimating peak flood discharges.
3. For a non-riverine SFHA, the Base Flood Elevation shall be the historic
Flood of Record plus three .feet (3), unless calculated by a detailed
engineering study.
4. For an unmapped extended SFHA (with a drainage area less than one
square mile) which has been identified by the Director of Engineering &
Community Development pursuant to Section 8-11-4A-3, the base flood
elevation shall be determined by the applicant utilizing a method as
approved in this Section 8-11-5.
8-11-6 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. 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 8-11-9.
A. Development Permit.
1. No person, firm, corporation, or governmental body not exempted by law
shall commence any development in the SFHA without first obtaining a
development permit from the Director . of Engineering & Community
Development.
2. Application for a development permit shall be made on a form provided by
the Director of Engineering & Community Development.
a. The application shall be accompanied by drawings of the site, drawn to
scale, showing property line dimensions and legal description for the
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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.
b. 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
8-11-9 of this Ordinance.
3. Upon receipt of a development permit application, the Director of
Engineering & Community Development shall compare the elevation of the
site to the base flood or 100 -year frequency flood elevation.
a. 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.
b. The Director of Engineering & Community Development 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.
4. A soil erosion and sediment control plan for disturbed areas shall be
submitted. 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.
5. The Director of Engineering & Community Development 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 Director of Engineering & Community Development shall not
issue a permit unless all other federal, state, and local permits have been
obtained.
B. Preventing Increased Damages.
No development in the flood fringe shall create a threat to public health and
safety.
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1. 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 floodplain.
2. Compensatory Storage.
a. Whenever any portion of a floodplain 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 tines 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 floodplain storage lost below the existing 10 -year flood elevation
shall be replaced below the proposed 10 -year flood elevation. All
floodplain storage lost above the existing 10 -year flood elevation shall be
replaced above the proposed 10 -year flood elevation.
e. All, such excavations shall be constructed to drain freely and openly to
the watercourse.
C. 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 Village of Elk
Grove Village to construct the lowest floor of a residential building below the
BFE in the flood fringe. The Director of Engineering & Community
Development shall not issue such a permit unless the applicant has complied
with all the criteria set forth in the following subsection. .
1. Compensatory storage shall be provided per Section 8-11-6 B.2.
2. he 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).
3. 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
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structure.. However, if site conditions are such that this requirement
cannot be met, the Director of Engineering & Community Development
may waive the ten (10) foot minimum setback if an Illinois Licensed
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 Director of Engineering &
Community Development for review. The Director of Engineering &
Community Development 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.
4. 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
Director of Engineering & Community Development may waive the
twenty (20) foot minimum setback distance if an Illinois Licensed
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 Village of Elk Grove Village for review. In no case shall
the setback distance be less than four (4) feet.
5. 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.
6. 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.
7. All fill material and compaction shall be designed, certified and inspected by
an Illinois Licensed Professional Engineer, as warranted by the site
conditions.
8. The basement floor shall be at an elevation that is no more than five (5)
below the BFE.
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9. There shall be a granular drainage layer beneath the floor slab, and minimum
of one quarter ('l4) 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.
10. The drainage system shall be equipped with a positive means of preventing
backflow.
11. All foundation elements shall be designed to withstand hydrostatic pressure
in accordance with accepted engineering practices.
12. If the applicant is unable to meet all of the requirements set forth in the
preceding paragraphs of this subsection, the Director of Engineering &
Community Development 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 Licensed Professional
Engineer.
13. 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.
8-11-7 Occupation and Use of Designated Floodways
This section applies to proposed development, redevelopment, site modification or
building modification within a designated floodway. The designated floodway for
Salt Creek, the Elk Grove Boulevard Drainage Ditch, the Unnamed Creek, the West
Branch of Salt Creek and the tributary to the West Branch of Salt Creek shall be as
delineated on the countywide Flood Insurance Rate Map of Cook County and
referenced in Section 8-11-2. 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 8-11-9.
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A. 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 Director of Engineering & Community
Development and IDNR/OWR.
Application for a development permit shall be made on a form provided by
the Director of Engineering & Community Development. 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;
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 the applicant or the applicant's agent;
i. If the applicant is a corporation, the president or other authorized officer
shall sign the application form;
j. If the applicant is a partnership, each partner shall sign the application
form; and
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:
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(1) 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;
(2) 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,
floodplain limit, specifications and dimensions of any proposed
channel modifications, location and orientation of cross-sections,
north arrow, and a graphic or numerical scale;
(3) 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);
(4) A soil erosion and sediment 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.
(5) A copy of the designated floodway map, marked to reflect any
proposed change in the designated floodway location.
m. Any and all other federal, state, and local 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 Subsection B of
this section.
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/OWR has indicated
conditional approval of the designated floodway map change. No
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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 floodplain and floodway limits; sealed by a
licensed professional engineer, licensed architect or licensed 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 8-11-9 of
this Ordinance.
q. If the proposed project involves a channel modification, the applicant
shall submit the following information:
(1) A discussion of the purpose of and need for the proposed
work;
(2) A discussion of the feasibility of using alternative locations or
methods (see 8-11-7.B.i.) to accomplish the purpose of the proposed
work;
(3) An analysis of the extent and permanence of the impacts each
feasible alternative identified in 8-11-7.B.i. of this Section would
have on the physical and biological conditions of the body of water
affected; and
(4) An analysis of the impacts of the proposed project, considering
cumulative effects on the physical and biological conditions of the
body of water affected.
2. The Director of Engineering & Community Development shall be
responsible for obtaining from the applicant copies of all other federal,
state, and local permits and approvals that may be required for this type of
activity.
a. The Director of Engineering & Community Development shall not issue
the development permit unless all required federal and state permits have
been obtained.
b. A Licensed Professional Engineer, under the employ or contract of the
Village of Elk Grove Village shall review and approve applications
reviewed under this Section
24
B. 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
natural 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 3708 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 relief outfalls;
d. Underground and overhead utilities;
e. Recreational facilities such as playing fields and trail systems, including
any related fencing (at least 50 percent open when viewed from any one
direction) built parallel to the direction of flood flows, and including
open air pavilions and toilet facilities (4 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 thereto;
h. Parking lots built at or below existing grade where either:
(1) The depth of flooding at the 100 -year frequency flood event will not
exceed 1.0 foot; or
(2) 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.
25
Designated floodway regrading, without fill, to create a positive non-
erosive slope toward a watercourse.
Floodproofing 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 floodwal
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 (50%) percent 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 (50%) percent 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.
2. Appropriate uses do not include the construction or placement of any new
structures, fill, building additions, buildings 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.
3. 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 licensed professional engineer
and provided that any structure meets the protection requirements of Section
8-11-9 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
26
designated floodway conveyance, the following factors shall be taken
into consideration:
(1) Designated floodway conveyance, "K" = (1.486/n)(ARB) 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).
(2) 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.
(3) Transition sections shall be provided and used in calculations of
effective 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:
(A) 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.
(B) When water is flooring 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.
(C) 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.
(D) Transition sections shall be provided between cross-sections with
rapid expansions and contractions and when meeting the
designated floodway delineation on adjacent properties.
(E) 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.
27
(1) 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.
(2) Compensatory storage for fill or structures shall be equal to at least
1.5 times the volume of floodplain storage lost.
(3) Artificially created storage lost due to a reduction in head loss behind
a bridge shall not be required to be replaced.
(4) 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.
(5) 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.
(6) There shall be no reduction in floodway surface area as a result of a
.floodway modification, unless such modification is necessary to
reduce flooding at existing structure.
c. Preservation of Floodway Velocities so as Not to Increase Stream
Erosion or Flood Heights.
(1) 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.
(2) 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.
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(1) 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.
(2) 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.
(A) 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 8-11-5 of this Ordinance. Bridges and Culverts must be
analyzed using any commonly accepted FEMA approved
hydraulic models.
(B) Lost floodway storage must be compensated for per Section 8-
11-7.B.b.
(C) Velocity increases must be mitigated per Subsection c of this
section.
(D) If the crossing is proposed over a public water that is used for
recreational or commercial navigation, an IDNR/OWR permit
must be received.
(E) 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 B.-
(F)
:
(F) All excavations for the construction of the crossing shall be
designed per Section B.3.h.
e. 'Reconstruction or Modification of Existing Bridges, Culverts, and
Approach Roads.
(1) 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 100 -year event, if the existing structure is not
a source of flood damage.
29
(2) If the existing bridge or culvert and roadway approach is a source of
flood damage to buildings or structures in the upstream floodplain,
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.
(3) 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 Ill. 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.
(1) 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.
(2) A permit'or letter indicating a permit is not required must be obtained
from II)NR/OWR for any structure built for the purpose of backing
up water in the stream during normal or flood flow.
(3) All dams and impoundment structures .as defined in Section 8-11-2
shall meet the permitting requirements of 17 Ill. 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:
(A) The impoundment is determined to be in the public interest by
providing flood control, public recreation, or regional stormwater
detention;
(B) The impoundment will not prevent the migration of indigenous fish
species, which require access to upstream areas as part of their life
cycle, such as for spawning;
(C) 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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(D) 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; .
(E) The project otherwise complies with the requirements of Section 8-
11-7.
g. Flood Proofing of Existing Habitable, Residential and Commercial
Structures.
(1) 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.
(2) Compensation of lost storage and conveyance will not be required
for floodproofing activities.
h. Excavation in the Floodway.
(1) 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
or other Appropriate Uses, transition sections shall be provided for
the excavation.
(2) 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:
(A)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; and
(B)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
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(C)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; and
(D)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:
(1) 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,
ankstabilization, flood proofing of existing structures, removal of
structures from the floodplain, 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:
(2) Water quality, habitat, and other natural functions would be
significantly improved by the modification and no significant habitat
area may be destroyed, or the impacts are offset by the replacement
of an equivalent degree of natural resource values;
(3) 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:
(A) 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.
(B) Hydraulically effective transitions shall be provided at both the
upstream and downstream ends of the project, designed such that
they will prevent erosion.
(C) 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.
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(D) Clearing of stabilizing vegetation shall be limited to that which is
essential for construction of the channel.
(E) 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
bioengineering 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.
(F) 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.
(G) 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.
(H) A sediment basin shall be installed at the downstream end of the
modification to reduce sedimentation and degradation of
downstream water quality.
(I) 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.
(J) 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.
(K) 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
(4) The project otherwise complies with the requirements of Section 8-
11-7
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J. 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:
(1) 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.
(2) 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.
(3) 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.
(4) A vegetated buffer strip of at least 25 feet in width shall be preserved
and/or re-established, where possible, along existing channels (See 8-
11-7.B.3.p.). 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 restabilized immediately.
(5) 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"
(MRCS, 1995).
1. Public Flood Control Projects.. For public flood control projects, the
permitting requirements of this section will be considered met if the
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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.
(1) The flood profiles, flows and floodway data in the designated
floodway study, referenced in Section 8-11-5, 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.
(2) 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:
(A) The requirements of this section for the 100 -year frequency flood
elevations of the designated floodway conditions; and
(B) Conditions with the receiving stream at normal water elevations.
(3) 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.
(1) 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 FEMA all 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.
(2) The final designated floodway map will not be changed by FEMA
until as -built plans or record drawings of initial filling, grading,
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dredging, or excavating activities are submitted and accepted by
FEMA and IDNR/OWR.
(3) 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.
(4) No filling, grading, dredging or excavating shall take place until a
conditional approval is issued.
(5) 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 licensed professional engineer.
p. For all activities in the floodway involving construction within 25 feet of
the channel, the following criteria shall be met:
(1) A natural vegetation buffer strip shall be preserved within at least 25
feet of the ordinary high water mark of the channel.
(2) 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 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.
4. 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.
Im
a. An engineer's analysis of the flood profile due to a proposed bridge
pursuant to Section 8-11-7B.3.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 8-11-7B.3.e.
c. Alternative transition sections and hydraulical equivalent storage
pursuant to Section 8-11-713.3.a, b. and h.
d. The construction of any IDNR/OWR projects, darns (as defined in
Section 8-11-2) and all other federal, state, 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.
5. 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 IDNWOWR shall be required if IDNWOWR has
delegated this responsibility to the Village of Elk Grove Village.
6. Permits for Dams.
a. Any work involving the construction, modification or removal of a dam
as defined in Section 8-11-2 per 17 I11. Adm. Code Part 3702 (Rules for
Construction of Dams) shalt obtain an IDNR/OWR permit prior to the
start of construction of a dam.
b. If the Director of Engineering & Community Development finds a dam
that does not have an IDNR/OWR permit, the Director of Engineering &
Community Development shall immediately notify the IDNR/OWR
Bartlett office.
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c. If the Director of Engineering & Community Development finds a dam
which is believed to be in unsafe condition, the Director of Engineering
& Community Development shall immediately notify the owner of the
dam, the IDNR/OWR Bartlett office, and the Illinois Emergency
Management Agency (IEMA).
7. Activities That Do Not Require a Licensed Professional Engineer's
Review.
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 may be permitted without a licensed professional engineer's
review. Such activities shall still meet the other requirements of this
Ordinance, including the mitigation requirements.
8-11-8 Occupation and Use of SFHA Areas Where Floodways Are Not Identified.
In SFHA or floodplains, (including AE, AH, AO and Unnumbered 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.
A. Development Permit.
1. No person, firm, corporation, or governmental body, not exempted by state
law, shall commence any development in a SFHA or floodplain without first
obtaining a development permit from the Director of Engineering &
Community Development.
2. Application for a development permit shall be made on a form provided by
the Director of Engineering & Community Development.
a. 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 elevations of the lowest
floor (including basement) of all proposed buildings subject to the
requirements of Section 8-1.1-9 of this Chapter.
b. The application for a development permit shall also include the
following information:
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(1) A detailed description of the proposed activity, its purpose, and
intended use;
(2) 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;
(3) Anticipated dates of initiation and completion of activity;
(4) Plans of the proposed activity shall be provided which include as a
minimum:
(A) 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;
(B) 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), floodplain
limit, location and orientation of cross-sections, north arrow, and
a graphical. or numerical scale;
(C) 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
(D) 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.
c. Engineering calculations and supporting data shall be submitted showing
that the proposed work will meet the criteria of Subsection B of this
Section.
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d. Any and all other federal, state, and local permits or approvals that may
be required for this type of development.
3. Based on the best available existing data according to federal, state or other
sources, the Director of Engineering & Community Development 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 8-11-5.D.
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 Director of Engineering & Community Development 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.
4. The Director of Engineering & Community Development 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 Director of Engineering & Community Development shall not
issue the development permit unless all required federal, state, and local
permits have been obtained.
B. Preventing Increased Damages.
1. No development in the SFHA inhere 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 functions of the floodway or channel, or impair
existing rater quality or aquatic habitat. Construction impacts shall be
minimized by appropriate mitigation methods as called for in this
Ordinance.
2. Within all riverine SFHAs where the floodway has not been determined, the
following standards shall apply:
a. The developer shall have a Licensed Professional Engineer state in
writing and show through supporting plans, calculations, and data that
the project meets the engineering requirements of Section 8-11-7.B.3.a.
.O
through 8-11-7.B.3.i. for the entire floodplain as calculated under the
provisions of Section 8-11-5.D.of this Ordinance.
(1) 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.
(2) Upon acceptance of the floodway by IDNR/OWR and FEMA, the
developer shall then demonstrate that the project meets the
requirements of Section 8-11-7 for the designated floodway. The
floodway shall be defined according to the definition in Section 8-
11-2 of this Chapter.
b. A development permit shall not be issued unless the applicant first
obtains a IDNR/OWR permit or a determination has been made that an
IDNR/OWR permit is not required.
c. Permits for Dams
(1) Any work involving the construction, modification or removal of a
dam as defined in Section 8-11-2 per 17 Ill. Adm. Code Part 3702
(Rules for Construction of Dams) shall obtain an IDNR/OWR permit
prior to the start of construction of a dam.
(2) If the Director of Engineering &.Community Development finds a
dam that does not have an IDNR/OWR permit, the Director of
Engineering & Community Development shall immediately notify
the IDNR/OWR Bartlett office.
(3) If the Director of Engineering & Community Development finds a
dam which is believed to be in unsafe condition, the Director of
Engineering & Community Development shall immediately notify
the owner of the dam, the IDNWOWR Bartlett office, and the
Illinois Emergency Management Agency (IEMA).
3. The following activities may be permitted without a Licensed Professional
Engineer's review or calculation of base flood elevation and designated
floodway. Such activities shall still meet the other requirements of this
Ordinance.
a. Bridge and culvert crossings of streams in rural areas meeting conditions
of IDNR/OWR Statewide Permit number 2;
b. Barge fleeting facilities meeting conditions of IDNR/OWR
Statewide Permit No. 3;
:1l
c. Aerial utility crossings meeting conditions of IDNR/OWR Statewide
Permit No. 4
d. Minor boat docks meeting conditions of IDNR/OWR Statewide Permit
No. 5;
e. 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:
f. Outfall structures and drainage ditch outlets meeting conditions of
IDNR/OWR Statewide Permit No. 7;
g. Underground pipeline and utility crossings meeting the conditions of
IDNR/OWR Statewide Permit No. 8;
h. Bank stabilization projects meeting the conditions of IDNR/OWR
Statewide Permit No. 9;
i.' Accessory structures and additions to existing residential buildings
meeting the conditions of IDNR/OWR Statewide Permit No. 10;
j. Minor maintenance dredging activities meeting conditions of
DNR/OWR Statewide Permit No. 11;
k. Bridge and culvert replacement structures and bridge widenings meeting
conditions of IDNR/OWR Statewide Permit No. 12;
1. Temporary construction activities meeting conditions of IDNR/OWR
Statewide Permit No. 13;
m. Special Uses of Public Waters. meeting conditions of IDNR/OWR
Statewide Permit No. 14; and
n. Any development determined by IDNR/OWR to be located entirely
within a flood fringe area shall be exempt from State Floodway permit
requirements.
4. The flood carrying capacity of any altered or relocated watercourse shall be
maintained.
5. Compensatory Storage.
a. Whenever any portion of a floodplain 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 floodplain storage lost below the existing 10 -year flood elevation
shall be replaced below the proposed 10 -year flood elevation. All
floodplain 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.
8-11-9 Permitting Requirements Applicable to All Floodplain Areas.
In addition to the requirements found in Sections 8-11-6, 8-11-7 and 8-11-8 for
development in flood fringes, designated floodways, and SFHA or floodplains where
no floodways have been identified, the following requirements shall be met.
A. Public Health Standards
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 flood protection
elevation (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
1003 of this ordinance.
2. Public utilities and facilities such as sewer, gas and electric shall be located
and constructed to minimize or eliminate flood damage.
3. 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.
4. 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.
5. All other activities defined as development shall be designed so as not to alter
flood flows or increase potential flood damages
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B. Carrying Capacity and Notification
1. For all projects involving channel modification, fill, or stream maintenance
(including levees), the flood carrying capacity of the watercourse shall be
maintained.
2. In addition, the Village of Elk Grove Village shall notify adjacent
communities in writing 30 days prior to the issuance of a permit for the
alteration or relocation of the watercourse.
C. Protecting Buildings.
1. All buildings located within a 100 -year floodplain, 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. Substantial improvements or structural alterations made to an existing
building that increase the floor area by more than twenty percent (20%) or
equal or exceed the market value by fifty percent (50%). Alteration shall
be figured cumulatively subsequent to the adoption of this ordinance. If
substantially improved, the existing structure and the addition must meet
the flood protection standards of this section.
b. 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.
c. 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).
d. Installing a travel trailer or recreational vehicle on a site for more than
180 days per year; and
e. Repetitive loss to an existing building as defined in Section 8-11-2. This
building protection requirement may be met by one of the methods
identified in Subsections 2 through 8 of this Subsection.
2. 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
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b. Fill Requirements:
(1) The fill shall be placed in layers no greater than six (6) 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
(2) 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
(3) The fill shall be protected against erosion and scour during flooding
by vegetative cover, riprap or other structural measure; and
(4) The fill shall be composed of rock or soil and not incorporate debris
or refuse materials; and
(5) 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.
3. 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 licensed
professional engineer or architect or the permanent openings, one on each
wall, shall be no more than one foot above existing grade, and consists 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; and
45
(1) 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
(2) 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
e. In lieu of the above criteria, the design methods to comply with these
requirements may be certified by licensed 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 Ill. Adm. Code Part 870. In addition, all manufactured homes shall
meet the following elevation requirements:
(1) 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.
(2). In the case of manufactured homes placed or substantially improved
in an existing manufactured home park or subdivision, the
manufactured home shall be elevated so that either the top of the
lowest floor is above the base flood elevation or the chassis 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 31 above unless:
(1) They are on site for fewer than 180 consecutive days; and,
(2) 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.
4. Only a non-residential building may be structurally dry floodproofed (in
lieu of elevation) provided that:
a. A licensed 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.
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).
5. A building may be constructed with a crawlspace located below the flood
protection elevation provided that the following conditions are met:
a. 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
b. 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
c. The interior grade of the crawlspace below the flood protection
elevation must not be more than 2 feet below the lowest adjacent
exterior grade; and
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d. The interior height of the crawlspace measured from the interior grade
of the crawl to the top of the foundation wall must not exceed 4 feet at
any point; and
e. 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
f. Portions of the building below the flood protection elevation must be
constructed with materials resistant to flood damage; and
g.' Utility systems within the crawlspace must be elevated above the
flood protection elevation.
6. 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 routes elevated to or above the level of the base flood elevation
shall be provided to all critical facilities.
7. Tool sheds, 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:
a. The building is not used for human habitation; and
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 8-11-7. In addition, all other
requirements of Section 8-11-6, 8-11-7 and 8-11-8 must be met; and
c. The structure shall be anchored to prevent flotation; and
d. Service facilities such as electrical and heating equipment shall be
elevated or floodproofed to the flood protection elevation; and
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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-
11-9.c.(3).(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.
8. Existing buildings located within a designated floodway shall also meet
the more restrictive Appropriate Use standards included in Section 8-11-
7. 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 8-11-7.B. 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.
8-11-10 ' Other Development Requirements
The Mayor and Board of Trustees shall take into account flood hazards, to the
extent that they are known in all official actions related to land management, use
and development.
A. New subdivisions, manufactured home parks, annexation agreements, and
Planned Unit Developments (PUDs) within the SFHA shall be reviewed to
assure that the proposed developments are consistent with Sections 8-11-6, 8-
11-7, 8-11-8 and 8-11-9 of this Ordinance and the need to minimize flood
damage. Plats or plans for new subdivisions, mobile home parks and Planned
Unit Developments (PUDs) shall include a signed statement by a Licensed
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).
B. Proposals for new subdivisions, manufactured home parks, travel trailer
parks, planned unit developments (PUDs) and additions to manufactured
home parks and additions to subdivisions shall include base flood or 100 -year
frequency flood elevation data and floodway delineations.
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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 8-11-5.1) and the floodway
delineation per the definition in Section 8-11-2.
C. 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 floodplains shall be included within parks or other
public grounds.
D. The Mayor and Board of Trustees shall not approve any Planned Unit
Development (PUD) or plat of subdivision located outside the corporate
limits unless such agreement or plat is in accordance with the provisions of
this Ordinance.
E. All other activities defined as development shall be designed so as not to alter
flood flows or increase potential flood damages.
8-11-11 Variances
No variances shall be granted to any development located in a designated
floodway as defined in Section 8-11-2. Whenever the standards of this
Ordinance place undue hardship on a specific development proposal, the
applicant may apply to the Department of Engineering & Community
Development for a variance. The Department of Engineering & Community
Development shall review the applicant's request for a variance and shall submit
its recommendation to the Mayor and Board of Trustees. The Village of Elk
Grove Village may attach such conditions to granting of a variance as it deems
necessary to further the flood protection intent of this ordinance.
A. No variance shall be granted unless the applicant demonstrates that all of the
following conditions are met:
1. The development activity cannot be located outside the SFF A; and
2. An exceptional hardship would result if the variance were not granted;
and
3. The relief requested is the minimum necessary; and
4. There will be no additional threat to public health, safety, beneficial
stream uses and functions, especially aquatic habitat, or creation of a
nuisance; and
5. There will be no additional public expense for flood protection, lost
environmental stream uses and functions, rescue or relief operations,
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policing, or repairs to streambeds and banks, roads, utilities, or other
public facilities; and
6. The provisions of Sections 8-11-6.13. and 8-11-8.13. of this Ordinance
shall still be met; and
7. The activity is not in a designated floodway; and
8. The applicant's circumstances are unique and do not establish a pattern
inconsistent with the intent of the NFIP; and
9. The granting of the variance will not alter the essential character of the
area involved including existing stream uses; and
10. All other required state and federal permits or waivers have been obtained
B. The Director of Engineering & Community Development shall notify an
applicant in writing that a variance from the requirements of Section 8-11-9
that would lessen the degree of protection to a building will:
1. Result in increased premium rates for flood insurance up to amounts as
high as $25 per $100 of insurance coverage; and
2. ,Increase the risks to life and property; and
3. Require that the applicant proceed with knowledge of these risks and that
the applicant will acknowledge in writing the assumption of the risk and
liability.
C. Variances requested in connection with restoration of a historic site or historic
structure as defined in 8-11-2 "Historic Structures", may be granted using
criteria more permissive than the requirements of Subsections 8-11-11.A and
B, subject to the conditions that:
1. The repair or rehabilitation is the minimum necessary to preserve the
historic character and design of the structure; and
2. The repair or rehabilitation will not result in the structure being removed
as a certified historic structure.
8-11-12 Disclaimer of Liability
A. 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.
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B. Larger floods may occur or flood heights may be increased by man-made or
natural causes.
C. This Ordinance does not imply that development, either inside or outside of
the SFHA, will be free from flooding or damage.
D. This Ordinance does not create liability on the part of the Village of Elk
Grove Village or any officer or employee thereof for any flood damage that
results from reliance on this Ordinance or any administrative decision made
lawfully thereunder.
8-11-13 Penalty
A. If such owner fails after ten days notice to correct the violation:
1. The Village of Elk Grove Village may make application to the Circuit
Court for an injunction requiring conformance with this Ordinance or
make such other order as the Court deems necessary to secure compliance
with this Ordinance.
2. 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.
3. A separate offense shall be deemed committed upon each day during or
on which a violation occurs or continues.
4. The Village of Elk Grove Village shall record a notice of violation on the
title to the property.
B. The Director of Engineering & Community Development 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.
The Director of Engineering & Community Development is authorized to
issue an order requiring the 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.
C. Nothing herein shall prevent the Village of Elk Grove Village from taking
such other lawful action to prevent or remedy any violations. All costs
connected therewith shall accrue to the person or persons responsible.
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8-11-14 Abrogation and Greater Restrictions
A. This Ordinance is not intended to repeal, abrogate or impair any existing
easements, covenants, or deed restrictions.
B. Where this Ordinance and other ordinance, easements, covenants, or deed
restrictions conflict or overlap, whichever imposes the more stringent
restrictions shall prevail.
C. 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 Village of
Elk Grove Village passed in order to establish initial eligibility for the
program.
8-11-15 Severability
The provisions and sections of this Ordinance shall be deemed separable and the
invalidity of any portion of this Ordinance shall not affect the validity of the
remainder.
8-11-16 Effective Date
This Ordinance shall be in full force and effect from and after its passage and
approval and publication, as required by law.
VOTE: AYES: 5 NAYS: 0 ABSENT:.1
PASSED this 151h day of July 2008.
APPROVED this 15`h day of July 2008.
APPROVED:
Mayor Crain B. Johnson
Village of Elk Grove Village
ATTEST:
Ann I. Walsh, Villalze Clerk
PUBLISHED this 18`h day of July, 2008, in pamphlet form.
Floodplainordina=2008 final.
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