G36-00 CITY OF ELGIN
ORDINANCE NO. G36-00
AN ORDINANCE
AMENDING TITLE 18, OF THE ELGIN MUNICIPAL
CODE, 1976, AS AMENDED, ENTITLED
"STORMWATER MANAGEMENT"
PASSED BY THE
CITY COUNCIL OF THE
CITY OF ELGIN
ON THIS 28TH DAY OF JUNE 2000
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Published in pamphlet form by authority of the
City Council of the City of Elgin, Kane and
Cook Counties, Illinois, on this
30th day of June 2000.
STATE OF ILLINOIS )
) ss.
COUNTY OF KANE )
CERTIFICATE
I, Dolonna Mecum, certify that I am the duly appointed and acting
municipal clerk of the City of Elgin, Cook and Kane Counties, Illinois.
I further certify that on June 28, 2000, the Corporate Authorities of such
municipality passed and approved Ordinance No. G36-00 entitled "An Ordinance
Amending Title 18 of the Elgin Municipal Code, 1976, as Amended, Entitled
"Stormwater Management," which provided by its terms that it should be published in
pamphlet form.
The pamphlet form of Ordinance No. G36-00, including the Ordinance and
r a cover sheet thereof, was prepared, and a copy of such Ordinance was posted in the
municipal building commencing on June 30, 2000, and continuing for at least ten days
thereafter. Copies of such Ordinance were also available for public inspection upon
request in the office of the municipal clerk.
DATED at Elgin, Illinois, on June 30, 2000.
Municipal Clerk
(SEAL)
ORDINANCE NO.: G36-00
AN ORDINANCE
AMENDING THE ELGIN MUNICIPAL CODE, 1976, AS AMENDED,
BY AMENDING TITLE 21, ENTITLED "STORMWATER MANAGEMENT"
WHEREAS, the City of Elgin is a home rule municipality as defined in Article VII,
Section 6A of the 1970 Constitution of the State of Illinois; and
WHEREAS, a home rule unit may exercise any power and perform any function
pertaining to its government and affairs; and
WHEREAS, the City Council of the City of Elgin desires to prevent accelerated soil
erosion and to control stormwater runoff resulting from earth changes proposed within the
city both during and after construction; and
WHEREAS, the City Council of the City of Elgin has determined it is necessary and
desirable to assure that property owners control the volume and rate of stormwater runoff
originating from their property so that surface water and groundwater quality is protected,
soil erosion minimized, and flooding potential reduced; and
WHEREAS,the City Council of the City of Elgin has determined it is necessary and
desirable to preserve and use the natural drainage system for receiving and conveying
stormwater runoff and to minimize the need to construct enclosed, below-grade storm drain
systems; and
WHEREAS, the City Council of the City of Elgin has determined it is necessary and
desirable to preserve natural infiltration and the recharge of groundwater and to maintain
subsurface flows which replenish lakes, streams and wetlands; and
WHEREAS, the City Council of the City of Elgin has determined it is necessary and
desirable to to restrict stormwater runoff entering and leaving development sites to
non-erosive velocities by requiring temporary and permanent soil erosion control
measures; and
WHEREAS, the City Council of the City of Elgin has determined it is necessary and
desirable to assure that soil erosion control and stormwater runoff control systems are
incorporated into site planning at an early stage in the planning and design process; and
WHEREAS, the City Council of the City of Elgin has determined it is necessary and
desirable to prevent unnecessary stripping of vegetation and loss of soils, especially
adjacent to lakes, streams, watercourses, and wetlands; and
WHEREAS, the City Council of the City of Elgin has determined it is necessary and
desirable to prevent construction activity that may cause mass movement, slumping, or
erosion of land surfaces; and
WHEREAS, the City Council of the City of Elgin has determined it is necessary and
desirable to eliminate the need for costly maintenance and repairs to roads,embankments,
ditches, streams, lakes, wetlands, and stormwater control facilities which are the result of
inadequate soil erosion and stormwater runoff control; and
WHEREAS, the City Council of the City of Elgin has determined it is necessary and
desirable to reduce long-term expenses and remedial projects which are caused by
uncontrolled stormwater runoff and soil erosion; and
WHEREAS, the City Council of the City of Elgin has determined it is necessary and
desirable to encourage the design and construction of stormwater control systems which
serve multiple purposes, including but not limited to flood prevention, water quality
protection,wildlife habitat preservation,education, recreation,and wetlands protection;and
WHEREAS, the City Council of the City of Elgin has determined it is necessary and
desirable to reduce the detrimental impacts of stormwater flows on downstream
communities.
WHEREAS, the City Council of the City of Elgin has determined it is necessary and
desirable to assure that all stormwater control facilities will be properly designed,
constructed, and maintained.
NOW, THEREFORE, BE IT ORDAINED by the City Council of the City of Elgin as follows:
Section 1. That Title 21, entitled "Stormwater Management," of the Elgin Municipal
Code, 1976, as amended, be and is hereby amended to read as follows:
21.01 PURPOSE
21.01.010 General
21.01.020 Applicability
21.01.030 Prevention of Damage
21.01.040 Purpose
21.02 RESERVED
21.03 APPLICABILITY
21.03.010 General
21.03.020 Specific Applicability
21.04 SUBMITTAL REQUIREMENTS
21.05 DEFINITIONS
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21.05.010 General
21.05.020 Definitions
21.06 ADMINISTRATION
21.06.010 General
21.06.020 Development Permits
21.06.030 Application Process
21.06.040 Variances
21.06.050 Penalty
21.06.060 Disclaimer
21.06.070 Fees
21.06.080 Bonds
21.06.090 Appeals from Permit Issuance or Denial
21.06.100 Suspension or Revocation of Permit
21.06.110 Exhibits
21.10 FLOODPLAIN MANAGEMENT
21.10.010 General
21.10.020 Floodplain Submittal
21.10.030 Base Flood Elevations
21.10.040 Occupation and Use of Flood Fringe Areas
21.10.050 Occupational and Use of Identified Floodways
21.10.060 Occupation and Use of SFHA Where Floodways Not Identified
21.10.070 Permit Requirements Applicable to All Floodplain Areas
21.20 SOIL EROSION AND SEDIMENTATION CONTROL
21.20.010 General
21.20.030 Soil Erosion and Sediment Control Submittal
21.20.040 Design Standards and Requirements
21.20.050 Construction Procedures and Requirements
21.30 STORMWATER CONTROL
21.30.010 General
21.30.030 Stormwater Management Submittal
rik 21.30.040 Wetland and Riparian Environment Submittal
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21.30.050 Drainage Design Requirements
21.30.060 Stormwater Detention Requirements
21.30.070 Fee-In-Lieu-Of
21.01 PURPOSE
21.01.010 General The provisions of this Title are not intended to repeal, abrogate or
impair any existing easements, covenants, or deed restrictions. Where the
ordinance codified in this Title and other ordinances, easements, covenants, or
deed restrictions conflict or overlap, whichever imposes the more stringent
restrictions shall prevail. The ordinance codified in this Title is intended to repeal
the original ordinance or resolution which was adopted to meet the National Flood
Insurance Program Regulations, but is not intended to repeal the resolution which
the City passed in order to establish initial eligibility for the program.
The provisions of this Title shall be deemed separable and the invalidity of any
portion of the ordinance codified in this chapter shall not affect the validity of the
remainder.
21.01.020 Applicability All development shall comply with the applicable provisions of
this Title 21 regulating floodplain management (Chapter 21.10), soil erosion and
sediment control (Chapter 21.20) and stormwater management (Chapter 21.30).
21.01.030 Prevention of Damage Development shall not:
A. Result in any new or additional expense to any person other than the
developer for flood protection or for lost environmental stream uses and
functions; nor
B. Increase flood elevations or decrease flood conveyance capacity upstream
or downstream of the area under the ownership or control of the developer;
nor
C. Pose any increase in flood velocity or impairment of the hydrologic and
hydraulic functions of streams and floodplains unless a watershed benefit is
realized; nor
D. Violate any provision of this code either during or after construction; nor
E. Degrade surface or groundwater quality.
21.01.040 Purpose It is recognized that runoff from uncontrolled development increases
flooding hazards and damage. The purposes of this Title are, in addition to those
purposes listed in Title 18, as follows:
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A. Prevent additional flood and erosion damages from new development in the
City of Elgin for both existing and future land development conditions;
B. Reduce or eliminate existing flood damages within the City of Elgin for both
existing and future land development conditions;
C. Protect new and existing buildings and major improvements to buildings from
flood damage;
D. Maintain eligibility for federally subsidized flood insurance for property in the
City by fulfilling the requirements of the National Flood Insurance Program;
E. Comply with the rules and regulations of the National Flood Insurance
Program, as amended, codified in the Code of Federal Regulations at 44
CFR 59-79, and the requirements of 18g of the Rivers, Lakes and Streams
Act, as amended (615 ILCS 5/18g).
F. Establish and maintain development regulations which definitively minimize
soil erosion through efficient construction phasing and ongoing stabilization
measures;
rik4 G. Prevent increases in flood damages downstream of the city on the Fox River;
H. Favor stormwater storage over stormwater conveyance as part of the overall
stormwater management strategy for the city;
I. Protect the existing aquatic ecology and water quality of the Fox River and
its tributaries in the city;
J. Increase greenway open space and passive recreation opportunities along
floodplains in the city using stormwater and floodplain management
strategies in conjunction with open space acquisition.
K. Protect human life and health from the hazards of flooding;
L. Lessen the burden on the taxpayer for flood control projects, repairs to flood-
damaged public facilities and utilities, and flood rescue and relief operations;
M. Maintain property values and a stable tax base by minimizing the potential
for creating areas damaged by flood risk, poor water quality, erosion or
degraded natural resources;
N. Provide for orderly growth and development pursuant to the city's official
plans to protect an environment that is especially sensitive to changes from
human activity;
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0. Implement a stormwater and floodplain management program which protects
and utilizes the natural drainage system, consolidates stormwater detention
facilities, and preserves natural areas and associated floodplains,
watercourses, ponds, and wetlands and expands greenways;
P. Conserve and enhance natural areas, encompassing woodlands, ponds,
wetlands, floodplains, watercourses, and areas of steep slope as natural
systems for stormwater control,soil erosion control,wildlife habitats, passive
recreation, and scenic vistas;
21.03 APPLICABILITY
21.03.010 General The contents of this Title supplement Titles 16, 18 and 19 of this code
and the requirements contained in this Title are in addition to the requirements of
such regulations.
21.03.020 Specific Applicability The provisions of this Title shall apply to all
development within the city with the sole exception of parcels for which final plats
of subdivision have been approved by the city and recorded prior to the effective
date of this ordinance and in which storm water control facilities have also been
approved by the city. The development of any parcel annexed to the city after the
effective date of this ordinance shall in all instances comply with all applicable
p1` provisions of this Title.
21.04 SUBMITTAL REQUIREMENTS
Each proposed development subject to this Title shall provide the following
submittals.
1. The name and legal address of the applicant and of the owner of the land;
and
2. The common address and legal description of the site where the
development will take place; and
3. Copies of all other permits or permit applications as required; and
4. A stormwater management submittal (21.30.040); and
5. A floodplain submittal (21.10.020), if development is proposed on a site
containing a floodplain; and
6. A wetland and riparian environment submittal (21.30.047), if development is
proposed on a site with wetlands and/or Waters of the United States; and
7. A soil erosion and sediment control submittal (21.20.030).
Exhibit 21-1 presents a flowchart for Title 21 submittals.
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21.05 DEFINITIONS
21.05.010 General The language set forth in the text of this chapter shall be interpreted
in accordance with the following rules of construction:
A. The singular number includes the plural and the plural the singular.
B. The present tense includes the past and future tenses, and the future
the present.
C. The word "shall" is mandatory, while the word "may" is permissive.
D. The masculine gender includes the feminine and neuter.
E. Whenever a word or term defined hereinafter appears in the text of
this Title, its meaning shall be construed as set forth in the definition
thereof;and any word appearing in parentheses, between a word and
its definition, shall be construed in the same sense as that word.
F. Words herein not defined shall be interpreted in accordance with
definitions contained in the most recent editions of commonly
available dictionaries and in conformance with federal or state laws
or regulations, where applicable.
21.05.020 Definitions For the purposes of this Title the following definitions are adopted.
A. Act means the Illinois "Rivers, Lakes and Stream Act," as amended (615
ILCS 5/4.9 et seq.).
B. Applicant means any person, firm, corporation, agency, business or other
entity which submits an application pursuant to Titles 13, 14, 16, 18, 19 or 21
of the Elgin Municipal Code, 1976, as amended, for any development.
C. Appropriate uses means uses in and of the regulatory floodway which are
permissible and eligible for permit issuance under this Title.
D. Base flood means the flood having a one percent probability of being
equaled or exceeded in any given year. The base flood is also known as the
one hundred-year frequency flood event. Application of the base flood
elevation at any location is as defined in Chapter 21.10.030 of this Title.
E. Base flood elevation (BFE) means the height of the base flood at any point
in relation to the National Geodetic Vertical Datum of 1929.
F. Building means a structure that is principally above ground and is enclosed
by walls and a roof. The term includes a gas or liquid storage tank, a
manufactured home, mobile home or a prefabricated building.This term also
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includes recreational vehicles and travel trailers to be installed on a site for
more than 180 days. If the travel trailer or recreational vehicle is on site for
less than one hundred eighty days, it must be fully licensed and ready for
highway use.
G. Buffer means an area of predominantly vegetated land located adjacent to
channels, wetlands, floodplains, waters of the U.S., lakes or ponds which
provides a reduction contaminants in stormwater that flows to such areas
and protects and enhances wildlife habitat and vegetation and permits
access to the body of water or feature.
H. Compensatory storage means an artificially excavated, hydraulically
equivalent volume of storage within the floodplain used to balance the loss
of existing flood storage within the floodplain. The uncompensated loss of
natural floodplain storage can increase off-site floodwater elevations and
flows.
I. Conditional approval of a regulatory floodway map change means
preconstruction approval by the city, IDNR-OWR and FEMA of a proposed
change to the floodway map. This preconstruction approval, 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.
J. Conditional letter of map revision (CLOMR) means a letter from FEMA
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.
K. Dam means 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. Underground water storage
tanks are not included.
L. Depressional Floodplain means any depression which stores more than
one acre-foot of runoff during the 100-year, 24-hour rainfall.
M. Designated Floodway means the channel, including on-stream lakes, and
that portion of the floodplain adjacent to a stream or watercourse as
designated by Elgin or IDNR-OWR or FEMA, which is needed to store and
convey the base 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 ten
percent increase in velocities.
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N. Detention Area means an area of land which provides for the temporary
storage of stormwater runoff.
0. Development means any completion of a plat, replat or manmade change
to real estate by any public or private entity, including:
1. Construction, substantial improvement or placement of a building or any
addition to a building;
2. Installation of a manufactured home on a site, preparation of a site for a
manufactured home or installation of a travel trailer or recreational vehicle
on a site for more than one hundred eighty days;
3. Drilling which is not part of an investigative study;
4. Mining, installation of utilities, construction of roads, bridges, or similar
projects valued at more than one thousand dollars;
5. Redevelopment of real estate;
6. Construction or erection of levees, walls, fences, dams, culverts or
channel modifications;
7. Filling, clearing, dredging, grading, excavating, paving, or other
nonagricultural alterations of the ground surface;
8. Storage of equipment, materials or deposit of solid, semi-solid or liquid
waste;
9. Any other activity that might change the direction, height, or velocity of
flood or surface water.
Development does not include the following:
1. Maintenance of existing buildings,
2. Resurfacing of pavement when there is no increase greater than four
inches in elevation and width, or
3. Gardening, plowing, and similar agricultural practices that do not involve
filling, grading, or construction of levees.
P. Director means the general services manager or designee.
Q. Elevation certificate means a form published by FEMA that is used to
certify the base flood elevation and the lowest elevation of useable space to
which a building has been constructed.
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R. Exempt organizations means organizations which are exempt from this
Title under state or federal law.
S. Engineering division means the Engineering Division of the Department of
Public Works of the City of Elgin.
T. Existing manufactured home park or subdivision means 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 paving of concrete pads)has been completed before
April 1, 1990.
U. Expansion to an existing manufactured home park or subdivision
means 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).
V. FEMA means the Federal Emergency Management Agency and its
regulations codified in the Code of Federal Regulations at 44 CFR 59-79, as
effective as of September 29, 1989. This incorporation does not include any
later editions or amendments to 44 CFR 59-79 since September 29, 1989.
W. Flood means a general and temporary condition of partial or complete
inundation of normally dry land from the unusual and rapid accumulation of
runoff or surface waters from any source.
X. Flood fringe means that portion of the floodplain outside of the regulatory
floodway.
Y. Flood Insurance Rate Map (FIRM) means 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.
Z. Floodplain means that land within the jurisdiction of the city subject to
inundation by the base flood with ground surface elevations at or below the
base flood elevation including special flood hazard areas (SFHAs), major
drainage systems, watercourses and depressional floodplains.
AA. Floodproofing means any combination of structural and nonstructural
additions, changes or adjustments to structures as permitted by this chapter
which reduce or eliminate flood damage to real estate or improved real
property, water and sanitary facilities, structures and their contents.
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AB. Floodproofing certificate means a form published by FEMA certifying that
a building has been designed and constructed to be structurally dry
floodproofed to the flood protection elevation.
AC. Flood protection elevation (FPE) means the elevation of the base flood
plus two feet of freeboard at any given location in the floodplain.
AD. Freeboard means an increment of elevation added to the base flood
elevation to provide a factor of safety for uncertainties in calculations,
unknown localized conditions, wave actions and unpredictable effects such
as those caused by ice or debris jams.
AE. Historic structure means any structure that is:
1. Listed individually in the National Register of Historic Places or
preliminarily determined by the Secretary of the Interior as meeting the
requirements for individual listing on the National Register;
2. Certified or preliminarily determined by the Secretary of the Interior as
contributing to the historic district;
3. Individually listed on the State Inventory of Historic Places by the
Illinois Historic Preservation Agency;
4. Individually listed on a local inventory of historic places that has been
certified by the Illinois Historic Preservation Agency.
5. Designated as a landmark by ordinance of the Elgin City Council
pursuant to the procedures set forth in Title 20 of this code.
AF. Hydrologic and hydraulic calculations means an engineering analysis by
a registered professional engineer to determine expected flood flows and
flood elevations based on land characteristics and rainfall events.
AG. Hydraulically equivalent means having the same volume of flood storage
between normal water elevation and the 10-year event elevation and
between the 10-year event elevation and the BFE for any floodplain
modification.
AH. IDNR-OWR means Illinois Department of Natural Resources-Office of Water
Resources.
Al. Letter Of Map Amendment(LOMA) means official determination by FEMA
that a specific structure or legally described parcel of land is not in a one
hundred-year flood zone; amends the FHBM or FIRM.
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AJ. Letter Of Map Revision (LOMR) means a letter that revises base flood or
one hundred-year frequency flood elevations, flood insurance rate zones,
flood boundaries or floodways as shown on an effective FHBM or FIRM.
AK. Major Drainage System means that portion of the stormwater management
system needed to store and convey the base flood beyond the capacity of
the minor drainage system
AL. Manufactured home means 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" does not include a "recreation
vehicle or travel trailer."
AM. Manufactured home park or subdivision means a parcel (or contiguous
parcels) of land divided into two or more manufactured home lots, sites or
zoning lots, for rent or sale.
AN. Minor Drainage System means that portion of the stormwater management
system consisting of street gutters, storm sewers, small open channels,
swales, and similar facilities designed to convey runoff from the 10 -year
eisk flood event or less.
AO. Mitigation Measures taken to eliminate or minimize damage from
development activities, such as construction in wetlands or regulatory
floodplain filling by replacement of the resource.
AP. Native Vegetation means wild plants within the Chicago Metropolitan region
prior to European settlement that are suited for the soil and geologic
attributes within the area of the Fox Valley which the city is located.
AQ. New manufactured home park or subdivision means 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) if completed on or after
April 1, 1990.
AR. NGVD means the National Geodetic Vertical Datum of 1929. NGVD plus
19.96 feet equals Elgin City Datum.
AS. NPDES means National Pollutant Discharge Elimination System permits
issued to insure that water quality standards are met.
fir• AT. Parcel means contiguous land under single ownership or control.
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AU. Public bodies of water means all open public rivers, streams, and lakes
specifically designated by IDNR-OWR that are capable of being navigated
by watercraft, in whole or in part, for commercial uses and purposes, or
which in their natural condition were capable of being improved and made
navigable, or that are connected with or discharged their waters into
navigable lakes or rivers within, or upon, the borders of the State of Illinois,
together with all bayous, sloughs, backwaters, lakes that are open to the
main channel or body of water and directly accessible thereto.
AV. Public flood control project means a flood control project which will be
operated and maintained by a public agency to reduce flood damages to
existing buildings and structures which includes a hydrologic and hydraulic
study of the existing and proposed conditions of the watershed. Nothing in
this definition shall preclude the design, engineering, construction or
financing, in whole or in part, of a flood control project by persons or parties
who are not public agencies.
AW. Recreational vehicle or travel trailer means a vehicle which is:
A. Built on a single chassis;
B. Four hundred 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 as temporary living quarters for recreation camping,
travel, or seasonal use and not for use as a permanent dwelling.
AX. Redevelopment means grading clearing or construction of a structure on a
platted parcel upon which a structure had been demolished.
AY. Registered land surveyor means a land surveyor registered in the state of
Illinois, under the Illinois Land Surveyors Act, as amended (225 ILCS
330/0.01 et seq.).
AZ. Registered professional engineer means an engineer registered in the
state of Illinois, under the Illinois Professional Engineering Act, as amended
(225 ILCS 325/0.01 et seq.).
BA. Repair, remodeling or maintenance development means development
activities which do not result in any increases in the outside dimensions of
building or any changes to the dimensions of a structure.
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BB. Riparian environment means land bordering a waterway that provides
habitat or amenities dependent on the proximity to water.
BC. Riverine SFHA means 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.
BD. Special Flood Hazard Area (SFHA) means any base flood area subject to
flooding from a river, creek, intermittent stream, ditch, or any other identified
channel or ponding as shown on a Flood Insurance Rate Map as Zone A,
AO, A1-30, AE, A99, AH, VO, V1-30, VE, V, M, or E. The SFHAs for Elgin
are shown in Exhibit 21-2 of this Title.
BE. Structure means the results of a manmade change to the land constructed
on or below the ground, including the construction, reconstruction or
placement of a building or any addition to a building; installing manufactured
home on a site; preparing a site for a manufactured home or installing a
travel trailer on a site for more than one hundred eighty days, unless they are
fully licensed and ready for highway use.
BF. Substantial improvement means any repair, reconstruction, rehabilitation,
addition or improvement of a structure, the cost of which equals or exceeds
fifty percent of the market value of the structure either, (a) before the
improvement or repair is started, or (b) if the structure has been damaged
from any source, and is being restored, before the damage occurred. This
term includes structures which were damaged whereby the cost of restoring
the structure to its predamaged condition would equal or exceed fifty percent
of the market value before the damage occurred, regardless of the actual
repair work performed. For the purposes of this definition "substantial
improvement" is considered to occur when the first alteration of any wall,
ceiling, floor, or other structural parts of the building commences, whether or
not that alteration affects the external dimensions of the structure. 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," provided that the alteration will not
preclude the structure's continued designation as a "historic structure."
BG. Transition section means reaches of the stream or floodway where water
flows from a narrow cross-section to a wide cross-section or vice versa.
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BH. Watercourse means any conveyance for surface runoff with a watershed
greater than 100 acres.
BI. Water Quality Best Management Practices means measures incorporated
into the stormwater management system to trap and assimilate stormwater
runoff pollutants. The preferred water quality best management practice in
Elgin is wetland detention.
BJ. Wetland Detention means a stormwater detention facility which supports
perennial wetland vegetation over at least two thirds of its surface area.
21.06 ADMINISTRATION
21.06.010 General The general services manager (Director) shall be responsible for
the general administration and enforcement of the provisions of this Title. The
powers and duties of the Director include, but are not limited to, the following:
A. Rules and Regulations. Adopt rules and regulations governing the
applications of these provisions, provided such rules shall not conflict with
any City ordinance, or any state or federal regulation.
B. Development Review. Review and direct modification for any development
as set forth in this Title.
C. Procedures. Establish procedures for application and review of permit
requests under this Title.
D. Floodplain and Floodway Determination. Require all new development to
determine whether it is in a floodplain.
E. State Floodplain Permit. Ensure that a development within a floodway or in
a floodplain which drains more than one square mile for which a detailed
study has not been conducted has obtained a permit from IDNR-OWR.
F. Other Permits. Insure that all required federal, state and local permits
governing development within a floodplain have been obtained; that a dam
safety permit has been issued, or a letter indicating no dam safety permit is
required has been obtained, if the proposed development activity includes
construction of a dam as defined in Section 21.10.020(L). Regulated dams
may include weirs, restrictive culverts or impoundment structures.
H. Plan Review and Permit Issuance. Ensure that all development within the
floodplains of the jurisdiction of the City meet the requirements of this Title
and issue a development permit in accordance with the provisions of this
Title and other regulations of this community when the development meets
the conditions of this and other Titles;
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I. Inspection Review. Inspect all development before, during and after
construction to assure they comply with the provisions of this chapter;
J. Elevation and Floodproofing Certificates. Maintain in the permit files
Elevation Certificates certifying the elevation of the lowest floor (including
basement)of a residential or nonresidential building or the elevation to which
a nonresidential building has been floodproofed, using a Floodproofing
Certificate,for all buildings subject to Section 21.10.070 of this Title for public
inspection and provide copies of same;
K. Records for Public Inspection. Maintain for public inspection and furnish
upon request base flood data, SFHA and regulatory floodway maps, copies
of federal or state permit documents, variance documentation, Conditional
Letter of Map Revision (CLOMR), Letter of Map Revision (LOMR), Letter of
a Map Amendment (LOMA) and "as built" elevation and floodproofing or
elevation and floodproofing certificates for all buildings constructed subject
to this chapter;
L. State Permits. Ensure that construction authorization has been granted by
the IDNR-OWR, for all development subject to Chapters 21.10.050 and
21.10.060 of this chapter. Upon acceptance of the ordinance codified in this
elk chapter by IDNR-OR and FEMA, responsibility is delegated to the City in
accordance with the provisions of 92 III. Adm. Code 708, as amended, for
construction in the floodway and floodplain when floodways have not been
defined in Sections 21.10.050 and 21.10.060 of this chapter. The following
review approvals are not delegated to the city and shall require review or
permits from IDNR-OWR.
1. Organizations which are exempt from this chapter under Illinois law;
2. IDNR-OWR projects, dams or impoundment structures as defined in
21.05.020 K and all other state, federal or local unit of government
projects, including projects of the City and county, except for those
projects meeting the requirements of Section 21.10.050 G;
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 Section 21.10.050 C. 5;
4. An engineer's analysis of the flood profile due to Section 21.10.050 C. 4;
5. Alternative transition sections and hydraulically equivalent compensatory
storage as indicated in Sections 21.10.050( C)(1)(2) and 8;
6. Permit issuance of structures within or over publicly navigable rivers,
lakes and streams;
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7. Any changes in the Base Flood Elevation for watercourses with a
drainage greater than one square mile or floodway locations; and
8. Base Flood Elevation determinations for watercourses with greater than
one square mile of drainage where none now exist.
M. Cooperation with Other Agencies. Cooperate with state and federal
floodplain management agencies to improve base flood or one hundred-year
frequency flood and floodway data and to improve the administration of this
Title. Submit data to IDNR-OWR and FEMA for proposed revisions of a
regulatory map. Submit responses as required for the National Flood
Insurance Program. Notify FEMA of any proposed amendments to this
chapter.
21.06.020 Development Permits No person,firm,corporation,or governmental body not
exempted by state law shall commence any development without first obtaining
a development permit from the Director. Each application for a Title 21
development permit shall indicate which of the following approvals are being
requested.
Stormwater Submittal (21.30)
Stormwater Submittal with Wetland Submittal (21.30.040)
Soil Erosion and Sediment Control Submittal (21.20)
Floodplain Submittal (21.10.020)
Floodplain Submittal for Occupation and Use of Flood Fringes (21.10.040)
Floodplain Submittal for Occupation and Use of Floodway (21.10.050)
Floodplain Submittal for Occupation and Use of SFHAs Where Floodways Are Not
Identified (21.10.060)
21.06.030 Application Process Upon receipt of a development permit application, the
Director shall compare the elevation of the site to the base flood elevation. Any
development located on land that can be shown to be higher than the base flood
elevation as of the site's first floodplain identification and has not been filled
without a permit is not in the floodplain and, therefore, not subject to the
requirements of Section 21.10. The Director shall maintain documentation of the
existing ground elevation at the development and certification that this ground
elevation existed prior to the date of the site's first floodplain identification.
21.06.040 Variances
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A. General No variances shall be granted to any development located in a
designated floodway as defined in Section 21.05.010(M). However, when a
development proposal is located outside of a designated floodway, and
whenever the standards of this chapter place undue hardship on a specific
development proposal,the applicant may apply to the Director for a variance.
The Director shall review the applicant's request for a variance and shall
submit its recommendation to the city council.
B. Standards No variance shall be granted unless the applicant demonstrates
that:
1. The development activity cannot be located outside the SFHA;
2. An exceptional hardship would result if the variance were not granted;
3. The relief requested is the minimum necessary;
4. There will be no additional threat to public health and safety or creation
of a nuisance;
5. There will be no additional public expense for flood protection, rescue or
relief operations, policing, or repairs to roads, utilities, or other public
facilities;
elibh
6. The provisions of Sections 21.10.050(A)and 21.10.070(B)of this chapter
shall still be met;
7. The activity is not in a regulatory floodway.
8. The applicant's circumstances are unique and do not represent a general
problem.
C. Notice The Director shall notify an applicant in writing that a variance from
the requirements of this chapter that would lessen the degree of protection
to a building will:
1. Result in increased premium rate for flood insurance up to amounts as
high as $25.00 for$100.00 of insurance coverage;
2. Increase the risks to life and property; and
3. Require that the applicant proceed with knowledge of these risks and that
he will acknowledge in writing that he assumes the risk and liability.
D. Historical Structures Variances requested in connection with restoration
of a historic site or historic structure may be granted using criteria more
permissive than the requirements of Section 21.10.080(B), subject to the
conditions that:
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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.
21.06.050 Penalty
A. Failure to comply with the requirements of a permit or conditions of a
variance resolution shall be deemed to be a violation of this chapter. Upon
due investigation,the Director may determine that a violation of the minimum
standards of this chapter exist. The Director shall notify the owner in writing
of such violation.
B. If such owner fails after ten days notice to correct the violation:
1. The city may make application to the circuit court for an injunction
requiring conformance with this chapter or make such other order as the
court deems necessary to secure compliance with the chapter.
2. Any person who violates the ordinance codified in this chapter shall,upon
conviction thereof, be fined not less than $50.00 or more than $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 city may record a notice of violation on the chapter to the property.
C. The Director 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.
D. Nothing herein shall prevent the city from taking such other lawful action to
prevent or remedy any violations. All costs connected therewith shall accrue
to the person or persons responsible.
21.06.060 Disclaimer The degree of flood protection required by this chapter is
considered reasonable for regulatory purposes and is based on available
information derived from engineering and scientific methods of study. Larger
floods may occur or flood heights may be increased by manmade or natural
causes. This chapter does not imply that development either inside or outside of
the floodplain will be free from flooding or damage. This chapter does not create
liability on the part of the city or any officer or employee thereof for any flood
damage that results from reliance on this chapter or any administrative decision
made thereunder.
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21.06.070 Fees Filing fees for site development permits and services shall be set from
time to time by the city council as shown in Exhibit A.
21.06.080 Bonds The owner or his agent shall file with the Director a performance bond,
letter of credit or other improvement security satisfactory to the city, in the amount
of one hundred and ten percent (110%) of the design engineer's opinion of cost
or other amount deemed sufficient by the Director. This is to cover all the costs of
improvements, landscaping, maintenance of improvements and landscaping, soil
erosion and sediment control measures, and construction engineering and
construction observation costs for a period equal to the estimated time to
complete the work as specified under the site development permit plus one year.
The performance bond or letter-of-credit shall contain language which states that
the bond cannot expire without the city receiving written notice, by certified mail,
60 days prior to the expiration date.
21.06.090 Appeals from Permit Issuance or Denial The Director's decision regarding
any site development application is considered final.
21.06.100 Suspension or Revocation of Permit In the event any permittee holding a
development permit pursuant to this ordinance violates the terms of the permit, or
carries on site development in such a manner as to adversely affect the health,
welfare, or safety of persons residing or working in the area of the development
"'' site or so as to be materially detrimental to the public welfare or injurious to
property or improvements in the area, the Director may suspend or revoke the
development permit.
Suspension of a permit shall be a written stop-work order issued by the Director
and delivered to the permittee or agent or the person performing the work. The
stop-work order shall be effective immediately, shall state the specific violations,
and shall state the conditions under which work may be resumed. A stop-work
order will remain in effect until the applicant can demonstrate to the satisfaction
of the Director that all conditions of the above stop work order have been
corrected.
21.06.110 Exhibits
Exhibit A
Fees
Filing fees for development permits and services shall be as follows:
1. Less than one acre of disturbance $100.00
2. One to five acres of disturbance $150.00
3. Disturbed areas of more than five acres $200.00
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Re-examination fees shall be as follow:
1. Less than one (1) acre-where the first site development plan is rejected
due to inadequate or unacceptable design, and additional fee of fifty
dollars ($50.00) shall be paid before a second review is made. Where a
site development plan is rejected a second time due to inadequate or
unacceptable design, an additional fee of seventy-five dollars ($75.00)
shall be paid before the third review or each succeeding review is made.
2. One (1)to five(5)acres-where the first site development plan is rejected
due to inadequate or unacceptable design, and additional fee of seventy-
five dollars($75.00)shall be paid before a second review is made.Where
a site development plan is rejected a second time due to inadequate or
unacceptable design, an additional fee of one hundred dollars ($100.00)
shall be paid before the third review or each succeeding review is made.
3. Areas of more than five (5) acres -where the first site development plan
is rejected due to inadequate or unacceptable design, and additional fee
of one hundred dollars ($100.00)shall be paid before a second review is
made. Where a site development plan is rejected a second time due to
inadequate or unacceptable design, an additional fee of one hundred
twenty-five dollars ($125.00)shall be paid before the third review or each
re' succeeding review is made.
21.10 FLOODPLAIN MANAGEMENT
21.10.010 General In an effort to clearly define pre- and post-development risk of
flooding due to the base flood,the city shall require floodplain mapping as follows:
Pre-Development
Watercourses
Depressional Floodplain
SFHAs
Floodways
Post Development
Watercourses
Depressional Floodplain
Major Drainage Systems
SFHAs
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ribk
Floodways
21.10.020 Floodplain Submittal Application fora development permit shall be made on
a form provided by the Director.The floodplain submittal shall include the following
items:
A. General Data Applicable to All Submittals
1. A delineation of the pre-and post-development floodplains and floodway
consistent with the requirements of Chapter 21.10.030 of this Title; and
2. Elevation survey drawings of all structures located on or near the site,
showing all structures including the lowest floor, point of entry, and
floodproofing elevations. This survey shall be prepared, signed, and
sealed by a land surveyor or professional engineer registered in the State
of Illinois.
B. Additional Submittals for Occupation and Use of Flood Fringe Areas. The
application shall include drawings of the site, drawn to scale, showing
property line dimensions and a legal description for the property sealed by
a licensed engineer or land surveyor, existing grade elevations at one-foot
contour intervals in NGVD and all changes in grade resulting from excavation
el,,, or filling; the location and dimensions of all development and all floodway
and floodplains as mapped from any FIRM and also based on the
appropriate BFE and site topography. For all proposed buildings, the
elevation of the lowest floor, including basement, lowest opening,and lowest
adjacent grade shall be shown on the submitted plans and the development
will be subject to the requirements of Section 21.10.070 of this chapter.
C. Additional Submittals for Occupation and Use of Identified Floodways. The
application shall include the following information:
1. Name and address of applicant;
2. Site location, including legal description of the property, drawn to
scale, on the regulatory floodway map indicating whether it is
proposed to be in an incorporated or unincorporated area;
3. Name of stream or body of water affected;
4. Description of proposed activity;
5. Statement of purpose of proposed activity;
6. Anticipated dates of initiation and completion of activity;
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7. Name and mailing address of the owner of the subject property if
different from the applicant;
8. Signature of applicant or the applicant's agent;
9. If the applicant is a corporation, the president or other authorized
officer shall sign the application form;
10. If the applicant is a partnership,each partner shall sign the application
form;
11. 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;
12. 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 any
waterbodies boundary lines, names of roads in the vicinity of
the site, graphic or numerical scale, one-foot contour intervals
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 in NGVD
adjacent property lines and ownership, drainage and flood
control easements, distance between proposed activity and
navigation channel (when the proposed construction is near a
commercially navigable body of water), regulatory floodway
limit, floodplain limits, channel modifications, location and
orientation of cross-sections, north arrow, and a graphic or
numerical scale;
c. Cross-section views of the project and hydrologic and hydraulic
calculations showing existing and proposed conditions
including principal dimensions of the work as shown in plan
view, existing and proposed elevations, normal water
elevation, ten-year frequency flood elevation, one hundred-
year frequency flood elevation, floodway limits and graphic or
numerical scales (horizontal and vertical);
d. A copy of the regulatory floodway map, marked to reflect any
proposed change in the regulatory floodway location.
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13. Any and all other local, state and federal permits or approval letters
that may be required for this type of development.
14. Engineering hydrologic and hydraulic and other calculations and
supporting data shall be submitted showing that the proposed work
will meet the permit criteria of Section 21.10.050(c).
15. If the regulatory floodway delineation or base 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 regulatory floodway map change. No structures may
be built until a letter of map revision has been approved by FEMA;
16. The application for a structure shall be accompanied by drawings of
the site,drawn to scale showing property line dimensions and existing
ground elevations in one-foot contours and all changes in grade
resulting from any proposed excavation or filling, and floodplain and
floodway limits; sealed by a registered professional engineer, or
registered land surveyor, the location and dimensions of all buildings
and additions to buildings; and the elevation of the lowest floor
(including basement) and lowest opening of all proposed buildings
subject to the requirements of Chapter 21.10.070 of this chapter.
D. Additional Submittals for Occupation and Use of Floodplains Where
Floodways Are Not Identified.
1. The application shall be accompanied by drawings of the site, drawn to
scale showing property line dimensions; and existing grade elevations
and all changes in grade resulting from excavation or filling, sealed by a
licensed engineer, architect or surveyor, the location and dimensions of
all buildings and additions to buildings; and the elevation at the lowest
floor (including basement) of all proposed buildings subject to the
requirements of Section 21.10.070 of this chapter.
2. The application for a development permit shall also include the following
information:
a. A detailed description of the proposed activity, its purpose, and
intended use;
b. Site location (including legal description) of the property, drawn to
scale, on the SFHA maps;
c. Anticipated dates of initiation and completion of activity;
r
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d. Plans of the proposed activity shall be provided which include as
minimum:
(1) A vicinity map showing the site of the activity, name of
waterbodies, 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 in NGVD, adjacent property
lines and ownership, drainage and flood control easements,
distance between proposed activity and navigation channel(when
the proposed construction is near a commercially navigable body
of water), floodplain limits, location and orientation of cross-
sections, north arrow, and a graphical 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, ten-year frequency
flood elevation, one hundred-year frequency flood elevation, and
graphical or numerical scales (horizontal and vertical);
e. Engineering calculations and supporting data shall be submitted
showing that the proposed work will meet the criteria of Section
21.10.060;
f. Any and all other local state and federal permits or approvals that may
be required for this type of development.
21.10.030 Base Flood Elevations and Floodways
A. Base Flood Elevation This chapter's protection standard is based on the
following floodplain sources for the City. All development with watercourses,
SFHAs or depressional floodplain must map a pre-development 100-year
floodplain using a base flood elevation from the following sources. All
development also must map post-development floodplains for watercourses,
SFHAs, depressional floodplain, and major drainage systems. Floodways
also shall be mapped for pre- and post-development conditions where they
have been identified.
B. Designated Rivers and Creeks. The base flood elevation for the SFHAs of the
Fox River, Tyler Creek (except as noted below), Randall Road Tributary,
Lords Park Tributary, Otter Creek and Poplar Creek, shall be as delineated
on the one hundred-year flood profiles in the Flood Insurance Study of the
City prepared by FEMA (or the Department of Housing and Urban
25
Development)and dated September 1, 1981, and such amendments to such
study and maps as may be prepared from time to time. Exhibit 21-2 presents
a list of these studies. The base flood elevation for the floodplains of those
parts of unincorporated Cook County and Kane County that are within the
extraterritorial jurisdiction of the City or that may be annexed into the City
shall be as delineated on the one hundred-year flood profiles in the Flood
Insurance Study of the county prepared by FEMA and dated September 1,
1981 for Kane County and December 4, 1984 for Cook County and such
amendments or revisions to such study and maps as may be prepared from
time to time. The base flood elevation for Tyler Creek in the Elgin Facilities
Planning Area shall be as delineated on the 100-year profiles in the Tyler
Creek Floodplain Mapping Report dated August 18, 1998.
C. Floodways. The regulatory floodways are designated for the Fox River, dated
February 17, 1980, March 1, 1982 and April 17, 1984; Otter Creek, dated June
4, 1996; Randall Road Tributary, dated March 1, 1982; Tyler Creek, dated March
1, 1982 (except as designated below); and, Lords Park Tributary dated March 1,
1982 on the Flood Boundary and Floodway Map prepared by FEMA. Poplar Creek
floodway shall be as designated on the Regulatory Floodplain Map prepared by
IDNR-OWR and dated July 1, 1977. The regulatory floodways for those parts of
incorporated Cook County and Kane County that are within the extraterritorial
.. jurisdiction of the City that may be annexed into the City are designated for the
Fox River, Randall Road Tributary, Tyler Creek, Lords Park Tributary and Poplar
Creek on the Flood Boundary and Floodway map prepared by FEMA (or
Department of Housing and Urban Development) and dated March 1, 1982 for
Kane County and December 4, 1984 for Cook County. The regulatory floodway
for the Tyler Creek within the Elgin Facilities Planning Area shall be taken from the
Tyler Creek Floodplain Mapping Report dated August 18, 1998. Exhibit 21-2
summarizes these sources. To locate the regulatory floodway boundary on any
site, the regulatory floodway boundary should be scaled off the regulatory
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
regulatory floodway boundary, IDNR-OWR should be contacted for the
interpretations.
D. Base Flood Elevation Data Not Available The following sources, in order, shall
be used to determine a base flood elevation where a detailed study as
described above is not available.
1. The base flood elevation for each SFHA delineated as an "AH Zone" or
"AO Zone" shall be that elevation (or depth) delineated on the FIRM of
the city.
26
2. The base flood elevation according to the best existing data available in
the Illinois State Water Survey Floodplain Information Repository.
3. Hydrologic and hydraulic calculations sufficient to establish a base flood
elevation for the 100-year event for the critical duration storm using Huff
rainfall distributions, Bulletin 70 Rainfall Depths, and a model accepted
by FEMA. Along any watercourses draining more than one square mile,
the above analyses shall be submitted to IDNR-OWR for approval, once
approved it must be submitted to the Illinois State Water Survey
Floodplain Information Repository for filing.
4. The historic flood of record plus three feet, may be used to determine the
BFE for non-riverine SFHA and depressional floodplain.
21.10.040 Occupation and Use of Flood Fringe Area
A. Occupation and Use of Flood Fringe Areas Generally Development in
and/or filling of the flood fringe will be permitted if protection is provided
against the base flood or one hundred-year frequency flood by proper
elevation,and compensatory storage and other provisions of this chapter are
met. No use will be permitted which adversely affects the capacity of
drainage facilities or systems. Developments located within the flood fringe
shall meet the requirements of this section, along with the requirements of
Section 21.10.070.
B. Use of Fill If fill is being used to elevate the development above the base
flood elevation for a SFHA, the applicant shall submit sufficient data and
obtain a CLOMR and then a LOMR from FEMA for the purpose of removing
the development from the SFHA.
C. Compensatory Storage 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 elevation shall be compensated for and
balanced by a hydraulically equivalent volume of excavation taken from
below the base flood elevation. The excavation volume shall be equal to 150
(one hundred fifty) percent of the total volume of storage lost due to the fill
or structure. In the case of SFHAs and watercourses, such excavation shall
be made opposite or adjacent to the areas so filled or occupied unless
certified by a Professional Engineer that they are Hydraulically equivalent.
All floodplain storage lost below the existing ten-year flood elevation shall be
replaced below the proposed ten-year flood elevation. All floodplain storage
lost between the existing ten-year flood elevation and 100-year flood
elevation shall be replaced between the proposed ten-year flood elevation
and 100-year flood elevation. All such excavations shall be constructed to
drain freely and openly to the channel.
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21.10.050 Occupation and Use of Identified Floodways
A. General This section applies to proposed development within a floodway.
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 Chapter 21.10.070.
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. Only those appropriate
uses codified at 17 Illinois Administrative Code 3708, as amended, will be
allowed. Appropriate uses do not include the construction or placement of
any new structures, fill, building additions, buildings on stilts, fencing
(including landscaping or planting designed to act as a fence) and storage
of materials except as specifically defined below as an appropriate use. The
approved appropriate uses are as follows:
1. Flood control structures,dikes,dams and other public works or private
improvements relating to the control of drainage, flooding, erosion,
water quality or habitat for fish and wildlife;
2. 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;
3. Storm and sanitary sewer outfalls;
4. Underground and overhead utilities;
5. Recreational facilities such as playing fields and trail systems
including any related fencing (at least fifty percent open when viewed
from any one direction)built parallel to the direction of flood flows, and
including open air pavilions;
6. Detached garages, storage sheds, or other nonhabitable accessory
structures without toilet facilities to existing buildings that will not block
flood flows, nor reduce floodway storage;
7. Bridges, culverts, roadways, sidewalks, railways, runways and any
modification thereto;
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8. Parking lots and any modifications thereto(where depth of flooding at
the hundred-year frequency flood event will not exceed 1.0 foot) and
aircraft parking aprons built at or below ground elevation;
9. Floodway regrading, without fill to create a positive nonerosive slope
toward a watercourse;
10. Floodproofing activities to protect previously existing lawful structures
including the construction of watertight window wells, elevating
structures, or construction of floodwalls around residential,
commercial or industrial principal structures where the outside toe of
the floodwall shall be no more than ten feet away from the exterior
wall of the existing structure, and, which are not considered
substantial improvements to the structure;
11. In the case of damaged or replacement buildings, reconstruction or
repairs made to a building that are valued at less than fifty percent of
the market value of the building before it was damaged or replaced,
and which do not increase the outside dimensions of the building;
12. Additions to existing buildings above the BFE that do not increase the
building's footprint and are valued at less than fifty percent of the
market value of the building.
C. Criteria for Construction Within the regulatory floodway as identified on
the regulatory floodway maps designated by IDNR-OWR, the construction
of an appropriate use will be considered permissible provided that the
proposed project meets the following engineering criteria and is so stated in
writing with supporting plans, calculations and data by a registered
professional engineer and provided that any structure meets the protection
requirements of Section 21.10.070 of this chapter:
1. 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 regulatory floodway
conveyance lost due to the project will be replaced for all flood events up
to and including the one hundred-year frequency flood. In calculating
effective regulatory floodway conveyance, the following factors shall be
taken into consideration:
a. Regulatory floodway conveyance: k = (1.486/n) (AR 2/3)
where "n" is Manning's roughness factor, "A" is the effective area of
the cross-section, and "R" is the ratio of the area to the wetted
perimeter. (See, Open Channel Hydraulics, Ven Te Chow, 1959,
McGraw-Hill Book Company, New York).
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b. 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 nonvegetative land cover.
c. Transition sections shall be provided and used in calculations of
effective regulatory 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:
(i) When water is flowing from a narrow section to a wider section,
the water should be assumed to expand no faster than at a rate of
one foot horizontal for every four feet of the flooded stream's
length.
(ii) When water is flowing from a wide section to a narrow section, the
water should be assumed to contract no faster than at a rate of
one foot horizontal for every one foot of the flooded stream's
length.
(iii)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.
(iv)Transition sections shall be provided between cross-sections with
rapid expansions and contractions and when meeting the
regulatory floodway delineation on adjacent properties.
(v) All cross-sections used in the calculations shall be located
perpendicular to flood flows.
2. Preservation of Floodway Storage So As Not to Increase Downstream
Flooding. Compensatory storage shall be provided for any 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.
Compensatory storage for fill or structures shall be 150 (one hundred
fifty) percent of the volume of floodway storage lost. The compensatory
regulatory floodway storage shall be placed between the proposed
normal water elevation and the proposed one hundred-year flood
elevation.All regulatory floodway storage lost below the existing ten-year
flood elevation shall be replaced below the proposed ten-year flood
elevation.All regulatory floodway storage lost above the existing ten-year
30
flood elevation shall be replaced above the proposed ten-year flood
elevation. All such excavations shall be constructed to drain freely and
openly. If the compensatory storage will not be placed at the location of
the proposed construction, the applicant's engineer shall demonstrate to
IDNR-OWR through a determination of flood discharges and water
surface elevations that the compensatory storage is hydraulically
equivalent.
3. Preservation of Floodway Velocities So As Not to Increase Stream
Erosion or Flood Heights. For all appropriate uses, except bridges or
culverts or on-stream structures, the proposed work will not result in an
increase in the average channel or regulatory floodway velocities.
However, 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.
4. Construction of New Bridges or Culvert Crossings and Roadway
Approaches. The proposed structure shall not result in an increase of
upstream flood stages greater than 0.1 foot when compared to the
existing conditions for all flood events, up to and including the one
hundred-year frequency event,or the upstream flood stage increases will
be contained within the channel banks (or within existing vertical
extensions of the channel banks) such as within the design protection
grade of existing levees or flood walls or within recorded flood
easements. If the proposed construction will increase upstream flood
stages greater than 0.1 feet, the developer must contact IDNR-OWR,
Dam Safety Section for a dam safety permit 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 21.10.030
of this chapter. Culverts must be analyzed using the U.S. DOT, FHWA
Hydraulic Chart for the Selection of Highway Culverts or equivalent
accepted by IDNR-OWR. Bridges must be analyzed using the U.S.
DOT/Federal Highway Administration Hydraulics of Bridge Waterways
calculation procedures or equivalent accepted by IDNR-OWR.
b. Lost floodway storage must be compensated for per subsection
21.10.050(C)(2)of this section.
c. Velocity increases must be mitigated per subsection 21.10.050(C)(3)
of this section.
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d. If the crossing is proposed over a public waterway 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 IDNR-OWR for concurrence that a CLOMR is not
required by Section 21.10.050.
f. All excavations for the construction of the crossing shall be designed
per subsection 21.10.050(C)(8) of this section.
5. Reconstruction or Modification of Existing Bridges, Culverts, and
Approach Roads.
a. 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 one hundred-year event, if the existing structure
is not a source of flood damage.
b. 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, but this shall not adversely
affect the flood stages or damages on upstream and downstream
properties.
c. 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 the Department of Natural Resources regulations
codified at 17 Illinois Administrative Code, Chapter 1, Subchapter h,
Part 3708 ("Floodway Construction in Northeastern Illinois"), as
amended, and submitted to OWR for review and concurrence before
a permit is issued.
6. On-Stream Structures Built for the Purpose of Backing Up Water. Any
increase in upstream flood stages greater than 0.0 foot when compared
to the existing conditions, for all flood events up to and including the one
hundred-year frequency event shall be contained within the channel
banks (or within existing vertical extensions of the channel banks) such
as within the design protection grade of existing levees or flood walls or
within recorded flood easements. A permit or letter indicating a permit is
not required must be obtained from IDNR-OWR, Dam Safety Section for
a dam safety permit or waiver for any structure built for the purpose of
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backing up water in the stream during normal or flood flow. All dams and
impoundment structures as defined in Section 21.05 shall meet the
permitting requirements codified at 17 Illinois Administrative Code 3702
("Construction and Maintenance of Dams"), as amended.
7. Floodproofing of Existing Habitable, Residential and Commercial
Structures. If construction is required beyond the outside dimensions of
the existing building, the outside perimeter of the floodproofing
construction shall be placed no further than ten feet from the outside of
the building. Compensation of lost storage and conveyance will not be
required for floodproofing activities.
8. Excavation in the Floodway. When excavation is proposed in design of
bridges and culvert openings, including the modifications to, and
replacement of, existing bridge and culvert structures, or to compensate
for lost conveyance for other appropriate uses, transition sections shall
be provided for the excavation. The following expansion and contraction
ratios shall be used unless an applicant's engineer can prove to IDNR-
OWR through engineering calculations or model tests that more abrupt
transitions may be used with the same efficiency:
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 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;
c. When expanding or contracting flows in a vertical direction, a
minimum of one foot vertical transition for every ten feet of a stream
length shall be used;
d. Erosion/scour protection shall be provided inland upstream and
downstream of the transition sections.
9. Mitigation Plan. For all activities located in a floodway, an ecological
mitigation plan shall be submitted by the applicant. The ecological
mitigation plan shall demonstrate measures to be included in the
construction plans to preserve and enhance existing terrestrial and
aquatic ecology, water quality, and native vegetation. The requirements
of Chapter 21.20 shall be met.
10.Public Flood Control Projects. For public flood control projects, the
permitting requirements of this section will be considered met if the
applicant can demonstrate to IDNR-OWR through hydraulic and
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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 one
hundred-year frequency event.
11. General Criteria for Analysis of Flood Elevations.
a. The flood profiles, flows and floodway data referenced in Section
21.10.030 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.
b. If the one hundred-year regulatory floodway elevation at the site of the
proposed construction is affected by backwater from a downstream
receiving stream with a larger drainage area, the proposed
construction shall be shown to meet the requirements of this section
for the one hundred-year frequency flood elevations of the regulatory
floodway conditions and conditions with the receiving stream at
normal water elevations.
c. 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.
12. Conditional Letter of Map Revision. If the appropriate use would result in
a change in the regulatory floodway location or the one hundred-year
frequency flood elevation, the applicant shall submit to IDNR-OWR and
to FEMA all the information, calculations and documents necessary to be
issued a conditional regulatory floodway map revision and receive from
IDNR-OWR a conditional approval of the regulatory floodway change
before a permit is issued. However,the final regulatory floodway map will
not be changed by FEMA until as-built plans or record drawings are
submitted and accepted by FEMA and IDNR-OWR. In the case of
nongovernment projects, the municipality in incorporated areas and the
county in unincorporated areas shall concur with the proposed conditional
regulatory floodway map revision before IDNR-OWR approval can be
given. No filling, grading, dredging or excavating shall take place until a
conditional approval is issued. No further development activities shall
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take place until a final letter of map revision (LOMR) is issued by FEMA
and IDNR-OWR.
13. Professional Engineer's Supervision. All engineering analyses shall be
performed by, or under the supervision of, a registered professional
engineer.
14. After receipt of conditional approval of the regulatory floodway change
and issuance of a permit and a conditional letter of map revision,
construction as necessary to change the regulatory 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 regulatory
floodway map is changed and a final letter of map revision is received.
The regulatory floodway map will be revised upon acceptance and
concurrence by IDNR-OWR and FEMA of the "as built" plans.
D. State Review For those projects listed below located in a floodway, the
following criteria shall be submitted to IDNR-OWR for their review and
concurrence prior to the issuance of a permit:
1. An engineer's analysis of the flood profile due to a proposed bridge
pursuant to Section 21.10.050(C)(4).
( 2. 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 21.10.050(C.)(5).
3. The alternative transition section and hydraulically equivalent storage
pursuant to Section 21.10.050(C)(1), (2) and (8).
4. The construction of any IDNR-OWR projects,dams,as defined in Section
21.05, and all other state, federal or local units of government projects,
including projects of the municipality or county.
5. An engineer's determination that a proposed bridge affected by
backwater from a downstream receiving stream may be built with a
smaller opening.
6. Projects which revise or establish the floodway and/or flood profiles.
7. Projects in public bodies of water.
E. Other Permits In addition to the other requirements of this chapter, 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 GIS ILCS 515 et
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seq. No permit from IDNR-OWR shall be required if the division has
delegated this responsibility to the City.
F. Dam Safety Permits. Any work involving the construction, modification or
removal of a dam as defined in Section 21.05, as amended, and further
regulated in 17 Illinois Administrative Code 3702 ("Rules for Construction of
Dams")shall obtain an IDNR-OWR Dam Safety permit prior to the start of
construction of a dam. If the Director finds a dam that does not have an
IDNR-OWR permit, the Director shall immediately notify the IDNR-OWR,
Northeastern Illinois Regulatory Program Section. If the Directorfinds a dam
which is believed to be in unsafe condition, the Director shall immediately
notify the owner of the dam IDNR-OWR, Northeastern Illinois Regulatory
Program Section and the Illinois Emergency Management Agency (IEMA).
G. Activities That Do Not Require a Registered Professional Engineer's
Review. The following activities may be permitted without a registered
professional engineer's review. Such activities shall still meet the other
requirements of this chapter, including the mitigation requirements.
1. Underground and overhead utilities that:
a. Do not result in any increase in existing ground elevation, or
b. Do not require the placement of above ground structures in the
floodway, or
c. In the case of underground stream crossings, the top of the pipe or
encasement is buried a minimum of three feet below the existing
stream bed, and
d. In the case of overhead utilities, no supporting towers are placed in
the floodplain and are designed in such a fashion as not to catch
debris.
e. Disturbance of streamside vegetation shall be kept to minimum during
construction to prevent erosion and sedimentation. All disturbed
floodway areas, including the stream banks shall be restored to their
original contours and seeded with native vegetation or otherwise
stabilized upon completion of construction.
f. A utility crossing carrying material which may cause water pollution as
defined by the Illinois Environmental Protection Act (415 ILCS 5/1 et
seq.), as amended, shall be provided with shut-off valves on each
side of the body of water to be crossed.
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g. All rules and regulations promulgated by the Illinois Commerce
Commission shall be satisfied and the city, state, and federal
requirements for clearance must be satisfied.
2. Storm and sanitary sewer outfalls that:
a. Do not extend riverward or lakeward of the existing adjacent natural
bank slope, and
b. Do not result in an increase in ground elevation, and
c. Are designed so as not to cause stream erosion at the outfall location.
3. Construction of sidewalks, athletic fields (excluding fences), properly
anchored playground equipment and patios at grade;
4. Construction of shoreline and streambank protection that:
a. Does not exceed one thousand feet in length,
b. Materials are not placed higher than the existing top of bank,
c. Materials are placed so as not to reduce the cross-sectional area of
the stream channel or bank of the lake;
5. Temporary stream crossings in which:
a. The approach roads will be 0.5' (one-half foot) or less above natural
grade;
b. The crossing will allow stream flow to pass without backing up the
water above the stream bank vegetation line or above any drainage
tile or outfall invert;
c. The top of the roadway fill in the channel will be at least two feet
below the top of the lowest bank. Any fill in the channel shall be non-
erosive material, such as rip-rip or gravel;
d. All disturbed stream banks will be seeded or otherwise stabilized as
soon as possible upon installation and again upon removal of
construction;
e. The access road and temporary crossings will be removed within one
year after authorization.
21.10.060 Occupation and Use of SFHA Areas Where Floodways Are Not Identified
A. General In SFHAs where no floodways have been identified and no base
flood or one hundred-year frequency flood elevations have been established
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by FEMA, 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 obstruct flood flows or increase potential flood
damage outside the development due to increased flood heights, velocities
or loss of floodplain storage.
B. Comparison of Elevation Based on the best available existing data
according to the Illinois State Water Survey's Floodplain Information
Repository, the Director shall review the applicant's comparison of the
elevation of the site to the base flood or one hundred-year frequency flood
elevation. Should no elevation information exist for the site, the applicant
shall calculate the elevation according to Section 21.10.030. Any
development located on land that can be shown to have been higher than
the current base flood elevation as of the sites first Flood Insurance Rate
Map Identification is not in the SFHA and, therefore, not subject to the
requirements of this chapter. The building official shall maintain
documentation of the existing ground elevation at the development site and
certification that this ground elevation existed prior to the date of the site's
first Flood Insurance Rate Map identifications.
C. Standards Within Riverine SFHA Within all riverine SFHAs where the
floodway has not been determined, the following standards shall apply:
1. The developer shall have a registered professional engineer state in
writing and show through supporting plans,calculations,and data that the
project meets the engineering requirements of Section 21.10.050(C)(1)
through (14) for the entire SFHA as calculated under the provisions of
Section 21.10.030 of this Title. As an alternative, the developer should
have an engineering study performed to determine a floodway and
submit that engineering study to IDNR-OWR for acceptance as a
regulatory floodway. Upon acceptance of their floodway by IDNR-OWR,
the developer shall then demonstrate that the project meets the
requirement of Section 21.10.050 for the regulatory floodway. The
floodway shall be defined according to the definition in Section 21.05 of
this chapter.
2. A development permit shall not be issued unless the applicant first
obtains a permit from IDNR-OWR or written documentation that a permit
is not required from IDNR-OWR.
3. No permit from IDNR-OWR shall be required if permit responsibility has
been delegated to the city by IDNR-OWR in accordance with the
regulations codified at 17 Illinois Adminstrative Code, Part 3708
(Regulatory Flood ways), as amended.
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Ammlwam
4. Dam Safety Permit
a. Any work involving the construction, modification or removal of a dam
as defined in Section 21.05 and further regulated at 17 Illinois
Adminstrative Code Part 3702 (Rules for Construction of Dams), as
amende, shall obtain an IDNR-OWR permit prior to the start of
construction of dam.
b. If the Director finds a dam that does not have an IDNR-OWR permit,
he shall immediately notify the IDNR-OWR Schaumburg office.
c. If the Director finds a dam which is believed to be in unsafe condition,
he shall immediately notify the owner of the dam, the IDNR-OWR
Schaumburg office, and the Illinois Emergency Management Agency
(IEMA).
5. The following activities may be permitted without a registered
professional engineer's review or calculation of a base flood elevation
and regulatory floodway. Such activities shall still meet the other
requirements of this chapter:
a. Underground and overhead utilities that:
e'" (i) Do not result in any increase in existing ground elevations, or
(ii) Do not require the placement of above ground structures in the
floodway, or
(iii) In the case of underground stream crossings, the top of the pipe
or encasement is buried a minimum of three feet below the
existing stream bed, and
(iv) Overhead utility lines shall be constructed above the estimated
100-year frequency flood elevation or attached above the low
chord of an existing bridge (with the permission of the bridge
owner). No supporting towers shall be placed in the watercourse
and shall be designed so as to not catch debris.
(v) Disturbance of streamside vegetation shall be kept to minimum
during construction to prevent erosion and sedimentation.
(vi) A utility crossing carrying material which may cause water
pollution as defined by the Environmental Protection Act (415
ILCS 5/1 et seq.), as amended, shall be provided with shut-off
valves on each side of the body of water to be crossed.
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(vii) All Illinois Commerce Commission, National Electric Safety
Codes,state,and federal requirements for clearance must be met.
b. Storm and sanitary sewer outfalls that:
(i) Do not extend riverward or lakeward of the existing adjacent
natural bank slope, and
(ii) Do not result in an increase in ground elevation, and
(iii)Are designed so as not to cause stream bank erosion at the outfall
location.
c. Construction of shoreline and stream bed protection that:
(i) Does not exceed one thousand feet in length or two cubic yards
per lineal foot of stream bed,
(ii) Materials are not placed higher than the existing top of bank,
(iii) Materials are placed so as not to reduce the cross-sectional area
of the stream channel by more than ten percent.
d. Temporary stream crossings in which:
(i) The approach roads will be 0.5' (one-half foot) or less above
natural grade,
(ii) The crossing will allow stream flow to pass without backing up the
water above the stream bank vegetation line or above any
drainage tile or outfall invert,
(iii) The top of the roadway fill in the channel will be at least two feet
below the top of the lowest bank,
(iv) All disturbed stream banks will be seeded or otherwise stabilized
as soon as possible upon installation and again upon removal of
construction,
(v) The access road and temporary crossings will be removed within
one year after authorization.
e. The construction of light poles, sign posts and similar structures;
f. The construction of sidewalks, driveways, athletic fields (excluding
fences), patios and similar surfaces which are built at grade;
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6. The g. The
flood construction carrying of properly capacity within anchoredany altered, unor walled, open relocated structures watercourse
such as playground equipment, pavilions, and carports built at or
below existing grade that would not obstruct the flow of flood waters;
h. The placement of properly anchored buildings not exceeding seventy
(70) square feet in size, nor ten (10) feet in any one dimension (e.g.,
animal shelters and tool sheds);
i. The construction of additions to existing buildings which do not
increase the first floor area by more than twenty percent, which are
located on the upstream or downstream side of the existing building,
and which do not extend beyond the sides of the existing building that
are parallel to the flow of floodwaters;
j. Minor maintenance dredging of a stream channel where:
(i) The affected length of stream is less than one thousand feet,
(ii) The work is confined to reestablishing flows in natural stream
channels, or
(iii)The cross-sectional area of the dredged channel conforms to that
of the natural channel upstream and downstream of the site.
rift
shall be maintained.
D. Compensatory Storage Whenever any portion of a SFHA is authorized for
use, the volume of space which will be occupied by the authorized fill or
structure below the base flood or one hundred-year frequency flood elevation
shall be compensated for and balanced by a hydraulically equivalent volume
of excavation taken from below the base flood or one hundred-year
frequency flood elevation. The excavation volume shall be at least one
hundred fifty (150) percent of the volume of storage lost due to the fill or
structure. In the case of riverine SFHAs, such excavation shall be made
opposite or adjacent to the areas so filled or occupied. All storage lost below
the existing ten-year flood elevation shall be replaced below the proposed
ten-year flood elevation. All storage lost above the existing ten-year flood
elevation shall be replaced above the proposed ten-year flood elevation. All
such excavations shall be constructed to drain freely and openly.
21.10.070 Permit Requirements Applicable to All Floodplain Areas
A. General In addition to the requirements found in Sections 21.10.040,
21.10.050 and 21.10.060 for development in flood fringes, floodways and
SFHAs where no floodways have been identified (Zones A,AO,AH,AE,A1-
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A30, A99,VO,V1-30, VE,V, M or E)the following requirements shall be met
for all other floodplains:
B. Free Flow In all floodplains not defined as SFHAs no development shall be
permitted which would significantly impede or increase the flow and passage
of flood flows or significantly increase the BFE.
C. BFE Review The Director shall review the applicant's calculation of BFEs.
For SFHAs and watersheds greater than 640 acres, IDNR-OWR shall review
the calculations as well.
D. Development Permit A development permit shall not be issued unless
applicant obtains a permit from IDNR-OWR or a letter stating no permit is
required.
E. Compensatory Storage 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 one hundred-year frequency flood elevation
shall be compensated for and balanced by a hydraulically equivalent volume
of excavation taken from below the base flood or one hundred-year
frequency flood elevation. The excavation volume shall be at least one
hundred fifty (150) percent of the volume of storage lost due to the fill or
structure for SFHAs and one hundred (100) percent for watercourses. In the
case of riverine SFHAs and watercourses, such excavation shall be made
opposite or adjacent to the areas so filled or occupied. The volume of
excavation for depression storage shall be at least one hundred (100)
percent of the volume lost due to a fill or structure.
F. Storage of Hazardous Materials No developments in the floodplain shall
include locating or storing chemicals, explosives, buoyant materials, animal
wastes, fertilizers, flammable liquids, pollutants, or other hazardous or toxic
materials below the FPE.
G. Water and Sanitary Systems 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.
H. Carrying Capacity and Notification For all projects involving channel
modification,fill or involving stream maintenance(including levees),the flood
carrying capacity of the watercourse shall be maintained. In addition,the City
shall notify adjacent communities in writing thirty days prior to the issuance
of a permit for the alteration or relocation of the watercourse.
I. Protecting Buildings
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1. All buildings located within the floodplain shall be protected from flood
damage below the FPE. However, existing buildings located within a
floodway shall also meet the more restrictive appropriate use standards
included in Section 21.10.050. This building protection criteria applies to
the following situations:
a. Construction or placement of a new building;
b. A structural alteration to an existing building that either increases the
first floor area by more than twenty percent or the building's market
value by more than fifty percent(i.e.,a substantial improvement).This
alteration shall be figured cumulatively, beginning with any alteration
which has taken place subsequent to April 1, 1990;
c. Installing a manufactured home on a new site or a new manufactured
home on an existing site. This building protection requirement does
not apply to returning a mobile home to the same site it lawfully
occupied before it was removed to avoid flood damage; and
d. Installing a travel trailer on a site for more than one hundred eighty
days.
2. This building protection requirement may be met by one of the following
t methods contained in Sections 21.10.070(J) through (N).
J. Construction Requirements A residential or nonresidential building,when
allowed, may be constructed on permanent land fill in accordance with the
following:
1. The lowest floor (including basement) shall be at or above the flood
protection elevation.
2. The fill shall be placed in layers no greater than one foot deep before
compaction and should extend at least ten feet beyond the foundation of
the building before sloping below the flood protection elevation. The top
of the fill shall be above the flood protection elevation. However, the ten
foot minimum may be waived if a structural engineer certifies an
alternative method to protect the building from damages due to
hydrostatic pressures. The fill shall be protected against erosion and
scour. The fill shall not adversely effect the flow or surface drainage from
or onto neighboring properties.
K. Building Elevation Requirements A residential or nonresidential building
may be elevated in accordance with the following:
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1. 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.
The permanent openings shall be no more than one foot above 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.
2. 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.
3. All areas below the flood protection elevation shall be constructed of
materials resistant to flood damage. The lowest floor (including
basement) and all electrical, heating, ventilating, plumbing, and air
conditioning equipment and utility meters shall be located at or above the
flood protection elevation. Water and sewer pipes, electrical and
telephone lines, submersible pumps, and other waterproofed service
facilities may be located below the flood protection elevation.
4. The areas below the flood protection elevation may only be used for the
parking of vehicles, building access or storage of items not covered by
the standard flood insurance policy in an area other than a basement.
5. Manufactured homes and travel trailers to be installed on a site for more
than 180 days, shall be elevated to or above the FPE 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 Illinois Administrative
Code 870, as amended. In addition, all manufactured homes shall meet
the following elevation requirements:
a. In the case of manufactured homes placed or substantially improved
(a) outside of a manufactured home park or subdivision, (b) in a new
manufactured home park or subdivision, (c) in an expansion to an
existing manufactured home park or subdivision, or(d) 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.
b. 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
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lowest floor is above the base flood elevation or the chassis is at least
thirty-six inches in height above grade and supported by reinforced
piers or other foundations of equivalent strength, whichever is less.
6. Recreational vehicles or travel trailers shall be required to meet the
elevation and anchoring requirements of subsection (5) of this section
unless:
a. They are on site for less than one hundred eighty consecutive days;
and
b. They are fully licensed and ready for highway use. 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.
L. Dry Floodproofing Only a nonresidential building may be structurally dry
floodproofed (in lieu of elevation) provided that a registered professional
engineer 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 one hundred-year frequency flood. 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. 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.)
M. Tool Sheds and Detached Garages Tool sheds and detached garages on
an existing single-family platted lot, may be constructed with the lowest floor
below the flood protection elevation in accordance with the following:
1. The building is not used for human habitation;
2. All areas below the base flood or one hundred-year frequency flood
elevation shall be constructed with waterproof material. Structures
located in a regulatory 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 21.10.040. In addition, all
other requirements of Sections 21.10.040,21.10.050 and 21.10.060 must
be met;
3. The structure shall be anchored to prevent flotation;
4. Service facilities such as electrical and heating equipment shall be
elevated or floodproofed to the flood protection elevation;
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45
5. The building shall be evaluated at less than five thousand dollars and be
less than five hundred square feet in floor size;
6. The building shall be used only for the storage of vehicles or tools and
may not contain other rooms, workshops, green houses or similar uses.
N. Nonconforming Structures Nonconforming structures located in a
regulatory floodway may remain in use, and may only be enlarged, replaced
or structurally altered in accordance with Section 21.10.050. A
nonconforming structure damaged by flood, fire, wind or other natural or
manmade disaster may be restored unless the damage exceeds fifty percent
of its market value before it was damaged, in which case it shall conform to
this chapter.
O. Land Use Regulations The City council shall take into account flood
hazards, to the extent that they are known, in all official actions related to
land management, use and development.
1. New subdivisions, manufactured home parks, annexation agreements,
and planned unit development (PUDs) within the floodplain shall be
reviewed to assure that the proposed developments are consistent with
Sections 21.10.040,21.10.050,21.10.060 and 21.10.070 of this Chapter
and the need to minimize flood damage. Plats or plans for new
subdivisions, manufactured home parks and planned unit developments
(PUDs) shall include a signed statement by a registered professional
engineer that the plat or plans account for changes in the drainage of
surface waters in accordance with the Plat At (765 ILCS 205/0.01 et
seq.), as amended.
2. Proposals for new subdivisions, manufactured home parks, travel trailer
parks, planned unit developments (PUDs), additions to manufactured
home parks and additions to subdivisions shall include base flood
elevation data and floodway delineations. Where this information is not
available from an existing study filed with the IDNR-OWR, Illinois State
Water Survey or the City of Elgin, the applicant's engineer shall be
responsible for calculating the base flood elevation for all floodplains, per
Section 21.10.030;the floodway delineation for SFHAs, per the definition
in Section 21.05; and submitting it to the IDNR-OWR for watersheds
greater than one square mile and to the City for watersheds greater than
100 acres and depressional floodplain for review and approval as best
available regulatory data.
3. Streets, blocks, lots, parks and other public grounds shall be located and
laid out in such a manner as to preserve and utilize natural streams and
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channels. Wherever possible, the floodplains shall be included within
parks or other public grounds and linked to existing greenways.
4. The City council 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 chapter.
21.20 SOIL EROSION AND SEDIMENT CONTROL
21.20.010 General The following general principles shall apply to any movement of
earth and site development plan and the granting of a permit for the execution of
said site development plan as herein provided:
A. Site development shall be related to the topography and soils of the site so
as to create the least potential for erosion. Areas of steep slopes where
excavations and fills may be required shall be avoided wherever possible,
and natural contours shall be followed as closely as possible.
B. Natural vegetation shall be retained and protected wherever possible.
C. Areas within or immediately adjacent to natural swales, streams, lakes,
ponds,and wetlands shall be left undisturbed,wherever possible.Temporary
crossings, when permitted, must include appropriate stabilization and
sediment control measures.
D. All activities on the site shall be conducted on the smallest practical area of
land, in a logical and phased sequence to minimize the area of bare soil
exposed at any one time.
E. Sediment basins or traps, diversions, filter barriers, forebays and any other
appropriate measures shall be installed prior to beginning land disturbing
activity and maintained to remove sediment from runoff waters from land
undergoing development.
F. The selection of erosion and sediment control measures shall be based on
assessment of the probable frequency of climatic and other events likely to
contribute to erosion, and on evaluation of the risks, costs, and benefits
involved.
G. Provide for aesthetics and continual operation and maintenance in the
design of all erosion control facilities and practices.
H. Provisions shall be made to accommodate the increased run-off caused by
changed soil and surface conditions during and after development.
Drainageways and other erosion control facilities shall be designed so that
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their final gradients and the resultant velocities and rates of discharge will not
create additional erosion on-site or downstream.
I. Temporary vegetation or, where appropriate, mulching or other nonviable
cover shall be used to protect areas exposed during development.
J. Permanent vegetation and structures shall be installed and functional as
soon as practical during development.
K. Those areas being converted from agricultural purposes to other land uses
shall be vegetated with an appropriate protective cover prior to development.
L. All waste generated as a result of site development activity shall be properly
disposed of and shall be prevented from being carried off-site by either wind
or water.
M. Each site shall contain measures to prevent sediment from being tracked
onto public or private roadways. Included with these measures shall be the
removal of any material tracked on the roadways.
21.20.030 Soil Erosion and Sedimentation Control Submittal Each application shall
be accompanied by the following information:
fek A. Legend, scale, north arrow, project name, vicinity sketch, acreage of site,
and name address, phone number of owner(s), developer(s) and
engineer(s), engineer's signature and seal.
B. Existing and proposed topography at minimum two (2) foot contours
extending one hundred (100)feet beyond site boundaries. The Director may
require one (1) foot contours and additional spot elevations, for flat areas,
and areas within floodplains or drainageways, etc.Areas with slopes greater
than four percent (4%) shall be highlighted on the existing topography by
shading. Top of foundation or finished floor elevation shall also be provided
for existing structures. Show entire site on one sheet and on additional
sheets at a minimum scale of 1 " = 100'.
C. Predominant soil types and existing vegetative cover from actual field
identification.
D. Existing and proposed road ditches, drainageways, field tiles, storm drains,
culverts, and outfalls.
E. Location of existing and proposed buildings, structures, utilities, water
bodies, floodplains, wetlands, trees and shrubs, drainage facilities, paved
areas, right-of-way, easements and any other significant natural and man-
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made features on the site and adjacent land within one hundred (100) feet
of the site boundary.
F. Existing and proposed septic tank seepage fields and wells.
G. Limits of disturbance by clearing, grading, dredging, excavating, filling,
trenching, etc.
H. Delineate areas of permanent and temporary stabilization. Include seeding
mixtures and rates, sod specifications and method of anchoring, method of
seedbed preparation, expected seeding dates,type and rate of fertilizer and
lime application, and type and recommended method of mulching for both
temporary and permanent vegetative control measures, and types of non-
vegetative stabilization measures.
I. Location of all proposed sediment control measures.
J. Design specifications of all runoff control measures, including sediment
basins and traps, diversions, forebays, waterways, and outlets.
K. Standard details of all sediment control measures, including computations
for sediment basin and trap efficiencies and runoff volumes.
L. Design specifications to prevent tracking of soil off site from the land
disturbing activity, including temporary gravel surfaced staging areas and
access driveway.
M. Location of stockpile(s) and recommended method of stabilization.
N. Off-site waste or borrow quantities, location, and recommended methods of
stabilization.
O. Phasing of development site including:
1. Clearing and stripping,
2. Rough grading and underground construction,
3. Paving and final grading, and
4. Landscaping.
Phasing should identify the areas of the site being disturbed and sequence
of disturbance, the expected date in which clearing of each area will begin,
the estimated duration of exposure of cleared areas, the sequence of
installation and removal of temporary sediment control measures,installation
of storm drainage, paving streets and parking areas, establishment of
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temporary and permanent vegetative cover, and any other phases important
to the project.
P. Engineer's opinion of probable cost for stabilization, erosion and sediment
control measures and maintenance.
Q. Name, address, and phone number of the person who will have legal
responsibility for maintenance of erosion control structures and measures
during development until site is stabilized.
R. The submittal should be prepared in accordance with the standards and
requirements contained in the following publications and which should also
be referenced to on the plans:
1. "Procedures and Standards for Soil Erosion and Sedimentation Control
in Northeastern Illinois," (latest edition) prepared by the Northeastern
Illinois Erosion and Sedimentation Control Steering Committee.
2. `Standards and Specifications for Soil Erosion and Sediment Control, "
(latest edition) prepared by the Illinois Environmental Protection Agency.
3. "Standard Specifications for Road and Bridge Construction," (latest
edition), prepared by the Illinois Department of Transportation.
The City may waive specific requirements for the content of submissions
upon finding that the information submitted is sufficient to show that the work
will comply with the objectives and principles of this ordinance.
21.20.040 Design Standards and Requirements
A. Erosion and Other Pollutant Control Requirements
1. For disturbed areas draining less than one (1) acre, filter barriers
(including rock check dams, filter fences, straw bales, or equivalent
control measures) shall be constructed to control all runoff from the site
as specified in referenced handbooks. Vegetative filter strips, with a
minimum width of twenty-five (25) feet, may be used as an alternative
only where runoff in sheet flow is expected.
2. For disturbed areas draining more than one (1) but less than five (5)
acres,a sediment trap or equivalent control measure shall be constructed
at the down slope point of the disturbed area.
3. For disturbed areas draining more than five (5) acres, a sediment basin
or equivalent control measure shall be constructed at the down slope
point of the disturbed area.
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4. Sediment traps, barriers and basins shall be constructed and functional
prior to initiating land disturbing activity. Earthen structures such as
dams, dikes, and diversions must be seeded and mulched within seven
(7) days of installation.
5. Sediment basin and sediment trap designs shall provide for both
detention storage and sediment storage. The detention storage shall be
composed of equal volumes of "wet" detention storage and "live"
detention storage and shall be sized for the two (2)year,twenty-four(24)
hour runoff from the site under maximum runoff conditions during
construction. The release rate of the basin shall be the rate required to
achieve minimum detention times of at least ten (10)hours.The elevation
of the outlet structure shall be placed such that the outlet discharges at
a stable location.
6. The sediment storage shall be sized to store the estimated sediment load
generated from the site over the duration of the construction period with
a minimum storage equivalent to the volume of sediment generated in
one (1) year. For construction periods exceeding one (1) year, a yearly
sediment load and sediment removal schedule may be substituted.
7. Stormwater conveyance channels, including ditches, swales, and
diversions, and the outlets of all channels and pipes shall be designed
and constructed to withstand the expected flow velocity from the design
storm without erosion. All constructed or modified channels shall be
stabilized within forty-eight (48) hours, with the following standards:
a. For grades up to four percent (4%), seeding in combination with
mulch, erosion blanket or mat, or an equivalent control measure shall
be applied. Sod or erosion blanket or mat shall be applied to the
bottom of the channel.
b. For grades of four to eight percent (4% to 8%), sod or an equivalent
control measure shall be applied in the channel.
c. For grades greater than eight percent (8%), rock riprap or an
equivalent control measure shall be applied, or the grade shall be
effectively reduced using drop structures or rock ditch checks.
8. Disturbed areas shall be stabilized with temporary or permanent
measures within seven (7) calendar days following the end of active
disturbance, consistent with the following criteria:
a. Appropriate temporary or permanent stabilization measures shall
include seeding, mulching,sodding,and/or non-vegetative measures.
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b. Areas having slopes of greater than twelve percent (12%) shall be
stabilized with sod, erosion blanket or mat in combination with
seeding, or equivalent.
9. Land disturbing activities in stream channels shall be avoided, where
possible. If disturbance activities are unavoidable, the following
requirements shall be met:
a. Construction vehicles shall be kept out of the stream channel to the
maximum extent practicable. Where construction crossings are
necessary, temporary crossings shall be constructed of non-erosive
material, such as riprap or gravel.
b. The time and area of disturbance of stream channels shall be kept to
a minimum. The stream channel, including bed and banks, shall be
stabilized within forty-eight (48) hours after channel disturbance is
completed, interrupted, or stopped.
c. Whenever channel relocation is necessary, the new channel shall be
constructed and fully stabilized before flow is diverted.
10. Storm sewer inlets and culverts shall be protected by sediment traps or
filter barriers meeting accepted design standards and specifications.
11. Soil storage piles containing more than ten (10) cubic yards of material
shall not be located with a down slope drainage length of less than
twenty-five (25)feet to a roadway, drainage channel or water body. Filter
barriers, including filter fence, straw bales or equivalent, shall be installed
immediately on the down slope side at the base of the piles. If remaining
for more than fifteen (15) days, they shall be stabilized by vegetative
cover, mulching, or other means.
12. If dewatering devices are used, discharge locations shall be protected
from erosion. All pumped discharges shall be routed through
appropriately designed sediment traps or basins, or equivalent.
13. Each site shall have graveled (or equivalent) entrance roads, access
drives and parking areas of sufficient width and length to prevent
sediment from being tracked onto public or private roadways. Any
sediment reaching a public or private road shall be removed by street
cleaning (not flushing) before the end of each workday and transported
to a controlled sediment disposal area.
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14. All temporary and permanent erosion and sediment control practices
must be maintained and repaired as needed to assure effective
performance of their intended function.
15. All temporary erosion and sediment control measures shall be disposed
of within thirty (30) days after final site stabilization is achieved with
permanent soil stabilization measures. Trapped sediment and other
disturbed soils resulting from the disposition of temporary measures
should be permanently stabilized to prevent further erosion and
sedimentation.
B. Standards Adopted by Reference The submissions shall be prepared in
accordance with the standards and specifications contained in the following
publications:
1. "Illinois Urban Manual," latest edition.
2. "Procedures and Standards for Urban Soil Erosion and Sedimentation
Control in Illinois" (Revised July 1988 or latest edition) prepared by The
Urban Committee of the Association of Illinois Soil and Water Conservation
Districts".
3. "Standards and Specifications for Soil Erosion and Sediment Control"
(1987 or latest edition) prepared by the Illinois Environmental Protection
Agency.
4. "Standard Specifications for Road and Bridge Construction", (latest
edition) prepared by the Illinois Department of Transportation.
These publications are hereby incorporated into this ordinance and made a
part hereof by reference, for the purpose of exemplifying the considerations
and factors which should enter into the preparation of a site development
plan. In the event of conflict between provisions of said manuals and of this
ordinance, the more restrictive provisions shall govern.
C. Applicability of Provisions The requirements of this section shall not be
applicable to any site application filed prior to the effective date of this
ordinance.
21.20.050 Construction Procedures and Requirements
A. Applicability All land disturbing activity not specifically exempted by the
provisions of this ordinance shall be subject to the applicable standards and
requirements set forth in this ordinance.
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rik
B. Maintenance of Control Measures All soil erosion and sediment control
measures necessary to meet the requirements of this ordinance shall be
maintained, periodically in accordance with acceptable schedule by the
applicant or subsequent landowner during the period of land disturbance and
development of the site, in a satisfactory manner to ensure adequate
performance.
C. Construction Observations The Director and/or designer shall observe
and inform the applicant of deficiencies for that portion of work that fails to
comply with the site development plan as approved. Where it is found by
observation that conditions are not substantially as stated or shown in said
plan,the Director may stop further work until a revised site development plan
conforming to the existing conditions is found to be acceptable to the city.
Observations shall be in accordance with the following schedule, and the
permittee shall notify the Director at least two (2) working days before said
observation is to be made:
1. Prior to proceeding with any land disturbance and upon completion of
installation of sediment and runoff control measures (including perimeter
controls and diversions);
2. After stripping and clearing;
3. After rough grading;
4. After final grading;
5. After seeding and landscaping deadlines; and
6. After final stabilization and landscaping, prior to removal of sediment
controls.
If land disturbing activities are to be done in phases or areas, the permittee
shall give notice and request construction observation at completion of each
of the above work stages in each phase or area. If an observation is not
made and notification of the results given within ten (10)working days after
notice is received by the city from the permittee, the permittee may continue
work at their own risk,without presuming acceptance by the city. Notification
of the results of the inspection shall be given in writing at the site.
D. Special Precautions
1. If at any stage of site development the Director determines by
observation that the nature of the site is such that further work as
authorized by an existing permit is likely to imperil any property, public
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way, watercourse, stream, lake, wetland, or drainage structure, the
Director shall advise, and may require as a condition of allowing the work
to continue, that certain reasonable special precautions be taken as is
considered advisable to avoid the likelihood of such peril. "Special
precautions" may include, but shall not be limited to, specifying a more
level exposed slope;construction of additional erosion control or drainage
facilities, berms, terracing, compaction, or cribbing; installation of plant
materials for erosion control; and obtaining and implementing the
recommendations of a soils engineer, engineering geologist or biologist.
2. Where it appears that storm damage may result because the grading on
the development site is not adequate, work may be stopped and the
permittee required to install temporary structures or take such measures
as may be required to protect adjoining property or the public safety. On
large developments or where unusual site conditions prevail,the Director,
may specify the time of grading and time of completion or may require
that the operations be conducted in specific stages so as to insure
completion of protective measures or devices prior to the advent of
seasonal rains.
E. Retention of Plans and Permit Site development plans bearing the
approval of the Director, shall be maintained on the site during the progress
of the work. The permittee shall post the permit issued in a location visible
during construction.
F. Amendment of Plans Major amendments of the site development plans
shall be submitted to the Director and shall be processed and accepted or
disapproved in the same manner as the original plans. Field modifications of
a minor nature may be authorized by the Director, by written authorization to
the permittee.
21.30 STORMWATER CONTROL
21.30.010 General This chapter supplements Titles 16, 18, 19 and 21 of this code and
the requirements contained in this chapter are in addition to the requirements of
such regulations.
21.30.020 Reserved
21.30.030 Stormwater Management Submittal A stormwater management submittal
is required for all development.
A. The stormwater management submittal shall include:
1. A site stormwater plan; and
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rik 2. Site runoff calculations; and
3. Site runoff storage calculations; and
4. Information describing off-site conditions; and
5. A sediment and erosion control plan (meeting Chapter 21.20); and
6. Description of water quality best management practices incorporated in
the development.
B. The site stormwater plan shall include:
1. A site topographic map depicting both existing and proposed contours of
the entire site, the area to be disturbed during development and all areas
100 feet beyond the site, or as required by the Engineering Division of
Public Works. The map shall be at a scale of at least one inch equals 100
feet or less (e.g., one inch to 50 feet), with a minimum contour interval of
one foot with accuracy equal to 0.5 foot of elevation; and
2. A plan view drawing of all existing and proposed stormwater facilities
features, at an appropriate scale, including all of the following:
a. Boundaries for watersheds tributary to all significant stormwater
facilities (i.e., channels, bridges, inlets, and the like), and all
watersheds 100 acres in size or greater along with their location; and
b. Major and minor stormwater systems(i.e.,storm water pipes,culverts,
inlets, and storage and infiltration facilities, and flooding limits under
base flood conditions for the major stormwater system); and
c. Roadways, structures, parking lots, driveways, sidewalks, and other
impervious surfaces; and
d. The nearest base flood elevations; and
e. All watercourses; and
f. All depressional floodplain.
3. Design details for all proposed stormwater facilities (i.e., major and minor
stormwater systems, storage basins, and outlet works, and the like); and
4. A scheduled maintenance program for the stormwater facilities, including:
a. Planned maintenance tasks; and
b. Identification of the person or persons responsible for performing the
maintenance tasks; and
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c. A description of the p ermanent
public access maintenance
easements granted or dedicated to, and accepted by Elgin; and
5. A schedule of implementation of the site stormwater plan; and
6. Upon completion of development, mylar record of the site stormwater
plan shall be submitted to the Engineering Department. Such drawings
shall be prepared, signed, and sealed by a land surveyor or professional
engineer and shall include calculations showing the "as-built" volume of
any compensatory and site-runoff storage.
C. The site runoff calculations shall include:
1. Water surface elevations underthe design and base flood condition of all
watercourses and the major stormwater systems, including cross section
data for open channels.
2. Documentation identifying the procedures, assumptions, and data used
to calculate hydrologic and hydraulic conditions for sizing both major and
minor stormwater systems.
3. Mapping of all existing conditions depressional floodplain areas which
store more than one-acre foot during the 100-year, 24-hour event; and
4. Mapping of the base flood for existing conditions for all mapped
floodplains and all watercourses.
D. The site detention calculations shall include:
1. Documentation identifying the procedures, assumptions, and data used
to calculate hydrologic and hydraulic conditions and to determine that the
allowable release rate and related storage volume requirements have
been met; and
2. Elevation-area-storage and elevation-discharge data for storage systems.
3. Information describing the off-site conditions shall include sufficient
information to allow evaluation of off-site impacts to, and resulting from,
the proposed development. Such information shall include:
a. A vicinity topographic map using, at a minimum, Elgin's most current
aerial topographic mapping covering (1) the entire upstream
watershed that drains to or through the site (2) the entire watershed
including the site to the point of known or assumed discharge, and (3)
water surface elevation; and
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b. A plan view drawing of existing and proposed stormwater facilities, at
the same scale as the vicinity topographic map or smaller, including:
(i) Watershed boundaries for areas draining through or from the
development; and
(ii) The location of the development within the watershed planning
area; and
(iii) Soil types, vegetation, and land cover conditions affecting
runoff upstream of the development site for any area draining
through or to the site.
(iv) Water table data, where available.
E. A sediment and erosion control submittal shall be provided to conform with
the requirements of Section 21.20 of this Title.
F. Information describing how best management practices are incorporated into
the site design. Such information shall include:
1. A description of best management practices that are incorporated into the
site design and how they will function. Include applicable design criteria
such as soil type, vegetation, and land cover conditions draining to the
e''' best management practice along with appropriate calculations; and
2. A description of the maintenance requirements.
3. A copy of the stormwater NPDES permit Notice of Intent(NOI)and Storm
Water Pollution Prevention Plan (SWPPP) submitted to the Illinois
Environmental Protection Agency.
21.30.040 Wetland and Riparian Environmental Submittal Development which
contains waters of the United States, including wetlands, shall prepare a wetland
and riparian environment submittal. The wetland and riparian environment
submittal shall include:
A. A delineation of Waters of the United States and wetlands consistent with the
requirements for wetland delineation by the Corps of Engineers and the
Natural Resources Conservation Service where appropriate; and
B. A functional assessment of the Waters of the United States and wetlands as
described in Chapter 21.30.050; and
C. The mitigation plan proposed to the Corps of Engineers for any Waters of the
United States or wetland impacts; and
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D. A plan for the continued management, operation, and maintenance of any
mitigation measures, including the designation of the person or persons
responsible for long term operation and maintenance and dedicated funding
sources.
E. All Section 404 and Section 10 permits and 401 certification (33 USC 403
and 1344).
21.30.050 Drainage Design Requirements The following requirements shall govern
the design for drainage of stormwater runoff:
A. Streets, lots, parks, and other areas shall be located and laid out in such a
manner as to conserve natural stream channels and detention areas.
B. Generally acceptable locations of the major drainage system in the design
of a subdivision include the following:
1. In a depressed median of a boulevard or parkway, provided the median
is wide enough to permit 4 (four) horizontal to 1 (one) vertical or flatter
side slopes;
2. Centered on the rear lot lines in a block, or entirely within the rear yards
of a single row of lots or parcels, provided in either case, the lots are
large enough to permit 4 (four) horizontal to 1 (one)vertical or flatter side
slopes along the major drainageway and a building site above the BFE
plus one foot exists on the front part of the lot.
3. In each of the foregoing cases, a drainage easement as determined by
the Director, shall be provided and shall conform substantially with the
lines of the major drainageway and shall be shown on the plat. The
easement shall permit necessary public channel maintenance and
improvement work and access of equipment; however, the easement
shall prohibit obstructing structures thereon by the owner.
C. Within-block Drainage. A continuous easement shall be provided along all
rear lot lines and drawn on the subdivision plat within which utility lines and
drainage may be located and maintained, but on which no accessory
buildings may be located or built. The utility-drainage easement shall be at
least ten feet wide.
D. Street Pavements Near Floodplain.The crown of street pavements hereafter
built or reconstructed adjoining or near floodplain shall not be lower than the
base flood elevation, minus six (6) inches.
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E. Storm sewers shall be designed to flow just full for the ten-year intensity-
duration-frequency curve. The maximum allowable width of the street gutter
flow from the face of the curb shall be limited to eight feet.
F. An overall drainage area layout plan showing the limits of the contributing
runoff broken down into areas contributing to each drainage pickup point,
shall be submitted with the paving and drainage plans. Drainage design with
the development shall be adequate to handle the entire contributing
watershed area,and its existing, proposed and probable future development,
and not the area under submission only.
G. Whenever a minor drainage system for a proposed subdivision or
commercial development is designed to outlet into an existing storm sewer
system, the existing storm sewer must be shown by calculations to be
adequate to carry the proposed flow.
H. Open channels used as part of a major drainage system shall be designed
with a minimum freeboard of two feet and a product of maximum velocity in
feet per second and depth in feet of four or less for the base flood.
I. The outlet for storm sewers shall have an appropriate outfall energy
dissipator.
J. The minimum pipe size for culverts and storm sewers as part of the minor
drainage system shall be twelve inches inside diameter,except the minimum
pipe size connecting one catchbasin with another catchbasin or manhole
may be ten inches inside diameter. The minimum clean-out velocity for all
pipes shall be two feet per second. Sewer design shall consider the need for
grates to prevent ingress but not egress from sewers greater than 10 inches
diameter. Storm sewer pipe materials shall meet State Standards and shall
be water tight.
K. Manhole and/or catch basin spacing between straight runs of pipe shall be
limited to a maximum spacing of three hundred feet for sewers thirty-six
inches or less in diameter, a maximum of five hundred feet for sewers over
thirty-six inches in diameter. Manhole and catch basin shall meet State
Standards, shall be precast concrete and shall be water tight unless
otherwise approved by the Director.
L. Stormwater facilities shall be designed so that runoff exits the site at a point
where flows will not damage adjacent property.
M. Minor drainage systems shall be sized to convey runoff from the tributary
watershed under fully developed conditions for the ten-year event of critical
duration.
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N. Major drainage systems shall be sized to carry at least the base flood with
appropriate consideration for larger events.
0. Design runoff rates shall be calculated by using event hydrograph methods.
HEC-1 SCS runoff method, TR-20, or TR-55 tabular method shall be used.
Discharge rates for watersheds smaller than 20 acres may use the Rational
Method. Event methods must incorporate the following assumptions:
1. Antecedent moisture condition = 2; and
2. Huff rainfall distribution.
P. Design runoff rate methods shall use tabular Illinois State Water Survey
Bulletin 70 northeast sectional rainfall statistics and shall calculate flow from
all tributary area upstream of the point of design.
Q. Major and minor stormwater systems shall be located within easements or
rights-of-way at least ten feet wide explicitly providing for public access for
their maintenance.
R. Maximum flow depths on any roadway shall not exceed six inches at the
roadway crown during the base flood condition.
•. S. Transfers of waters between watersheds shall be prohibited.
T. Stormwater facilities for runoff upstream of regional storage facilities shall
provide for conveyance or storage of flood waters without increased potential
for damage to real or personal property during base flood conditions.
U. Development shall incorporate water quality best management practices into
the site design to minimize increases in runoff rates, volumes, and pollutant
loads. Development shall attempt to incorporate the following criteria:
1. Preserve streams mapped on the Hydrological Atlases for Elgin and their
associated floodplains and wetlands.
2. Minimize impervious surfaces in development and redevelopment.
3. Prefer the use of vegetated swales and existing natural channels where
practical instead of storm sewers.
4. Infiltrate site runoff when practicable and necessary engineering features
to preserve infiltration capacity are provided.
5. Utilize wetland detention basins wherever possible and wet detention in
all other cases except for infiltration basins.
V. A field tile survey shall be required for any development in agricultural areas.
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W. The development plans shall address what opportunities exist for
preservation and/or establishment of greenways within the context of
stormwater management and site layout.
X. Development plans shall characterize the functional value of wetlands and
Waters of the United States.The following functional values shall be reported
at a minimum.
1. Plant list with characterization of native plant diversity using the Floristic
Quality Assessment as defined by Swink and Wilhelm current edition.
2. IDNR statement regarding plant and wildlife habitat for state and federally
endangered species.
3. IDNR statement regarding presence of Illinois Natural Areas Inventory or
Illinois Nature Preserves Commission sites.
4. Illinois Environmental Protection Agency stream classification from the
latest 305(b) report (33 USC 466). If no specific designation exists the
classification shall be the classification of the stream to which it is
tributary.
5. Drainage area for all streams.
Y. Buffers shall be provided for floodplain, Waters of the U.S. and wetlands
from the edge of their jurisdictional limit as follows.
1. 50-foot Buffer: Identification of Waters of the U.S. and wetlands as ADID
by USEPA and the Corps of Engineers, presence of state or federal
threatened or endangered species,designation as Natural Area or Nature
Preserve, classification by IEPA as an A or B stream segment, or a
tributary to such stream segment, or identification as a wetland with an
FQA greater than 20.
2. 30-foot Buffer: A stream segment classified by IEPA as C, or tributary to
such a segment or a wetland with an FQA greater than 10.
3. In no case shall a buffer be less than the width of the floodplain. If
floodplain fills meeting Section 21.10 are approved the buffer shall not be
less than the post-development floodplain. No buffers are required for
major drainage systems not meeting the definition of a watercourse.
4. Buffers may be disturbed only for the following activities:
a. Placement of underground utilities;
b. Detention or compensatory storage excavation;
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eimk c. Floodplain fills meeting the requirements of 21.10 provided that in no
case shall the buffer be less than required by 21.30.050 Y. 1 and 2.
d. Removal of predominantly non-native vegetation.
5. If buffers are disturbed, they shall be replanted in native vegetation. In no
case shall buffers be disturbed closer than 15 feet from the jurisdictional
boundary for Waters of the U.S. or wetland.
6. A 50-foot building setback shall be provided from all buffers.
Z. Mitigation for impacts to Waters of the U.S. and wetlands shall take place on-
site unless impracticable in the Director's opinion, and unless water quality
functional value is preserved.
AA. Design channel velocities shall not exceed the velocity in feet per second
obtained by dividing the number 4 (four) by the depth of flow in feet for the
base flood.
AB. No buildable lots shall contain floodplain, wetlands or Waters of the United
States.
21.30.060 Stormwater Detention Requirements
A. Sufficient storage shall be provided such that the probability of the post
development release rate exceeding 0.10 cfs/acre of development shall be
less than one percent (1.0%) per year and the probability of the post
development release rate exceeding 0.04 cfs/acre of development shall be
less than fifty percent (50%) per year. The Director may specify more
restrictive release rates where downstream conditions warrant.
B. Event hydrograph methods shall be used to calculate design runoff volumes.
They must be either HEC-1, SCS runoff method with reservoir routing option;
XP-SWMM SCS runoff method with either steady state or dynamic analysis;
TR-20 with reservoir routing option, or TR-55 tabular method with reservoir
routing. Event methods shall incorporate the following assumptions:
1. Antecedent moisture condition = 2,
2. Huff rainfall distribution, and
3. Twenty-four (24) hour duration storm with a one percent probability of
occurrence in any one year specified by Illinois Sate Water Survey
Bulletin 70 tabular northeast sectional rainfall statistics.
C. For sites where the undeveloped release rate is less than the maximum
allowable release rate in Paragraph A of this section, the developed release
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rate and corresponding site runoff storage volume shall be based on the
existing undeveloped release rate for the development site.
D. All hydrologic and hydraulic computations must be verified under a range of
expected downstream water surface elevations, from low flow through the
base flood elevations.
E. Responsibility for maintenance of all detention facilities shall be designated
on the final plat of subdivision or other recorded documents and final plans.
F. Detention facilities shall be designed and constructed with the following
characteristics:
1. A minimum of two feet of freeboard above the base flood elevation shall
be provided around the perimeter of the detention facility with the
exception of the overflow structure. Water surface elevations two feet
above the base flood elevation shall not damage the detention facility.
2. The detention facilities shall be accessible and easily maintained.
3. All outlet works shall function without human intervention or outside
power and shall operate with minimum maintenance.
., 4. Detention facilities shall facilitate sedimentation and catchment of floating
material.
5. Detention facilities shall minimize impacts of stormwater runoff on water
quality by incorporating best management practices. Storage equivalent
to 0.50 inches of runoff from the site shall be provided below the outlet
invert. A permanent pool, wetland or engineering to provide infiltration
shall be provided. Permanent pools shall generally be three feet deep.
6. Detention facilities shall provide an overflow structure and overflow path
that can safely pass excess flows through the development site. The
minimum design rate shall be 1.0 cfs/acre of area tributary to the storage
facility.
7. Detention facilities shall have a safety ledge appropriate to their design
and shall provide an assured means for egress under base flood and
normal water conditions.
8. Detention basin side slopes shall be 4:1 (horizontal : vertical) or flatter.
9. Maximum allowable water level fluctuation shall be 5 feet.
G. Detention facilities located within the regulatory floodplain shall
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1. Conform to all applicable requirements specified in Chapter 21.10 of this
Title; and
2. Store the required site runoff under all streamflow and backwater
conditions up to the base flood elevation; and
3. Not allow design release rates to be exceeded under any stream
elevation less than the base flood elevation.
H. Detention facilities located within the regulatory floodway shall
1. Meet the requirements for locating storage facilities in the regulatory
floodplain; and
2. Be evaluated by performing hydrologic and hydraulic analysis
consistent with the standards and requirements for Watershed Plans;
and
3. Provide a watershed benefit.
I. Developments with detention facilities that have off-site flow tributary to the
site shall meet the following requirements.
1. If the off-site area is less than 640 acres and the ratio of off-site to on-
site area is less than two, then the development either shall provide
25 percent more detention to accommodate runoff from the off-site
tributary watershed and the site, or shall store the site runoff and
convey off-site flows through the development while preserving the
existing flow and storage of the site.
2. If off-site area is greater than 640 acres or the ratio of off-site to on-
site area is greater than two, the development shall convey off-site
flows through the development while preserving the existing flow and
storage of the site.
3. The one-percent release rate in all instances shall remain at 0.10 cfs
per acre of development excluding off-site watersheds.
21.30.070 Fee-In-Lieu-Of
A. General The city has determined that detention for small development is
often impractical except where needed to protect downstream properties.
The small size of the detention facilities and very small outlets needed to
meet this Title can result in detention facilities which are difficult to maintain
and which often do not function as intended. To address this concern, the
city has implemented a fee-in-lieu-of detention option for small developments
and redevelopment.
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B. Applicability Development less than three acres in size for single family
residential uses, and less than one acre in size for all other uses, and all
redevelopment may request approval from the Director for fee-in-lieu-of
detention. Fee-in-lieu-of shall not be used to offset compensatory storage
requirements.
C. Criteria For Approval The Engineering Division of the Public Works
Department shall approve fee-in-lieu-of detention for development meeting
Section 21.30.070 B unless one or more of the following conditions are met:
1. Failure to provide on-site detention would create a drainage problem
on subservient properties as determined by the Director.
2. Inadequate minor and major drainage systems capacity exists
downstream of the development without the use of on-site detention.
3. Water quality best management practices in the form of on-site
detention are needed to protect receiving waters.
D. Fee New development shall pay a fee of $10,000 per acre of a parcel
cleared of vegetation or graded. If ten percent of the development is placed
in a deed restricted continuous greenway planted in native vegetation the fee
shall be reduced to$6,000 per acre.Acres cleared and graded but replanted
with native vegetation shall not be charged a fee.
Redevelopment shall pay a fee of $3,000 per acre of parcel.
If ten percent of the surface area of a development or redevelopment is
devoted to detention water quality best management practices designed to
store the 2-year, 24-hour runoff event then the fee shall be $3,000 per acre
for new development and $1,500 per acre for redevelopment.
Exhibit 21-1 (flow chart)
Exhibit 21-2
List of Current Flood Insurance Study Data
Item Panel Number Effective Date
F.I.S. 09/01/81
FIRM Panels Index 02/17/89
170087-0003C 03/01/82
170087-0004C 03/01/82
170087-0006D 04/17/84
170087-0007D 04/17/84
170087-0008C 03/01/82
_ 170087-0010E 02/17/89
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EXHIBIT 21-1
APPLICATION PROCESS
DEVEL OPMENT
STORtNI-WATER
WETLAND SOIL EROSION
FLOODPLAN
SUBMITTAL , RIPARLAN SUBMITTALS SED fN'T
ENVIRONMENTAL CONTROL
SUBMITTAL SFHA SUBMITTAL
PRESENT
ACRES
NO LESS THAN YES MEET 21.20
3 ACRES REQUIREMENTS
NO
YES
FLOOD-
WAY WAY - -
PRESENT
• DOWNSTREAM
YES _ DRANAGE
ISSUES NO
DEPRESSIONAL DEFINE BFE
NO FLOODPLAN -, YES - AND MAP
PRESENT FLOODPLAIN
NO FEE N
LIEU OF
NO
YES
WATER- FLOODPLAN
COURSE _ YES I PACTS
MEET 21.30 PRESENT
REQUIREMENTS
---- NO
YES
• WETLANDS OR FILL IMPACT FILL SFHA
NO
RIPARIAN DEPRESSIONAL
. FLOOD FLOOD-
FRINGE WAY FLOODPLAIN
PRESENT OR
NO WATERCOURSE
SUBMITTAL
MEET MEET I
YES 21.10.040 21.10.050 MEET
REQUIRE- REQUIRE- 21.10.060
NIENTS MENTS REQUIRE-
MEET 21.30.047 MENTS
REQUIREMENTS MAP POST DEVELOPMENT
FLOODPL AIN
AND FLOODWAY
I NO
INCLUDING MAJOR
DRAINAGE SYSTEM
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170087-0013C 03/01/82
Floodway Panels Index 02/17/89
170087-0003 03/01/82
170087-0004 03/01/82
170087-0006 03/01/82
170087-0007 03/01/82
170087-0008 03/01/82
170087-0010 02/17/89
LOMR 170087-0010E 12/27/91
170087-0003C 10/29/97
03/17/99
09/03/99
170087-0006D 03/17/99
LOMA-LOMR-F 1700087-0003C 04/21/92
03/08/94
Section 2. Severability. Should a court of competent jurisdiction determine that one
or more sections or subsections of this ordinance is or are invalid, the remaining sections
and subsections hereof shall remain in full force and effect.
Section 3. Repealer. Any and all ordinances, sections or subsections of ordinances
in conflict with the provisions of this ordinance are hereby repealed.
Section 4. Effective Date. This ordinance shall become effective upon its passage
and publication as required by law.
//
Ed Schock, Mayor
Presented: June 28, 2000
Passed: June 28, 2000
Vote: Yeas 7 Nays 0
Recorded: June 29 , 2000
Published: June 30, 2000
Attest:
Dolonna Mecum, City Clerk
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