(A) Interpretation of terms and words.
(1) Words used in the present tense include the future tense.
(2) Words used in the singular number include the plural number and words used in the plural number include the singular number.
(3) The words "shall," "will," and "must" are mandatory, not permissive.
(4) All distances, unless otherwise stated shall be measured horizontally.
(B) Definitions. For the purpose of this chapter, the following definitions shall apply unless the context clearly indicates or requires a different meaning.
ACCESSORY STRUCTURE. A non-habitable building which is on the same parcel of property as the principal building to be insured and the use of which is incidental to the use of the principal building.
ACT. An act in relation to the regulations of the rivers, lakes and streams of the State of Illinois, ILCS Ch. 615, Act 5, §§ 5 et seq.
APPLICANT. Any person, firm, corporation or agency which submits an application.
APPROPRIATE USES. Only uses of the regulatory floodway that are permissible and will be considered for permit issuance. The only uses that will be allowed are as specified in § 151.32(E).
ASCE. American Society of Civil Engineers.
BASE FLOOD. The flood having a 1% chance of being equaled or exceeded in any given year. The BASE FLOOD is also known as the 100-year flood.
BASE FLOOD ELEVATION (BFE). The height in relation to the North American Vertical Datum (NAVD) of 1988 (or other datum where specified) of the crest of the base flood. Application of the BFE at any location is as defined in § 151.30.
BASEMENT. Any area of the building, including any sunken room or sunken portion of a room, having its floor below ground level (subgrade) on all sides.
BEST MANAGEMENT PRACTICE (BMP). A measure used to control the adverse impacts of stormwater discharge on water quality downstream. BMP's include structural devices (e.g. grassed swales, filter strips and detention basins) designed to remove pollutants and reduce runoff volumes and non-structural measures such as public information on proper disposal and use of pesticides and herbicides.
BUFFER. An area of natural vegetation adjacent to channels, wetlands, lakes, ponds or other surface waters to be left in a natural condition for the purpose of eliminating or minimizing adverse impacts to such areas.
BUILDING. 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 includes recreational vehicles and travel trailers to be installed on a site for more than 10 days, unless they are fully licensed and ready for highway use.
BY-PASS FLOW. An approach that routes tributary drainage area runoff around and not through a stormwater control structure or without restriction through the stormwater control structure with an approved overflow facility.
CHANNEL. Any river, stream, creek, brook, branch, natural or artificial depression, ponded area, flowage, slough, ditch, conduit, culvert, gully, ravine, wash, or natural or man-made drainage way, which has a definite bed and banks or shoreline, in or into which surface or groundwater flows either perennially or intermittently.
CHANNEL MODIFICATION. Alteration of a channel by changing the physical dimensions or materials of its bed or banks. CHANNEL MODIFICATION includes damming, rip-rapping (or other armoring), widening, deepening, straightening, relocating, lining and significant removal of native vegetation from the bottom or banks. CHANNEL MODIFICATION does not include the clearing of dead or dying vegetation, debris, or trash from the channel. Channelization is a severe form of CHANNEL MODIFICATION involving a significant change in the channel cross-section and typically involving relocation of the existing channel (e.g., straightening).
COMPENSATORY STORAGE. An artificially excavated, hydraulically equivalent volume of storage within the floodplain used to balance the loss of natural flood storage capacity when artificial fill or structures are placed within the floodplain. The uncompensated loss of natural floodplain storage can increase off-site floodwater elevation and flows.
CONDITIONAL APPROVAL OF DESIGNATED FLOODWAY MAP CHANGE. Preconstruction approval by IDNR/OWR and FEMA of a proposed change to the floodway map. This preconstruction approval, pursuant to 17 Ill. Adm. Code Part 3708, gives assurances to the property owner that once an appropriate use is constructed according to permitted plans, the floodway may can be changed, as previously agreed, upon review and acceptance of as-built plans.
CONDITIONAL LETTER OF MAP AMENDMENT. A FEMA comment letter on a development proposed to be located in, and affecting only that portion of the area of floodplain outside the regulatory floodway and having no impact on the existing regulatory floodway or base flood elevations.
CONDITIONAL LETTER OF MAP REVISION (CLOMR). A letter providing FEMA’s comment on a proposed project that would, upon construction, affect the hydrologic or hydraulic characteristics of a flooding source and thus result in the modification of the existing floodway, the effective BFEs, or the SFHA.
CONTROL STRUCTURE. A structure designed to control the rate of flow that passes through the structure, given a specific upstream and downstream water surface elevation.
CRITICAL FACILITY. Any facility which is critical to the health and welfare of the population and, if flooded, would create an added dimension to the disaster. Damage to these CRITICAL FACILITIES can impact the delivery of vital services, can cause greater damage to the other sectors of the community, or can put special populations at risk.
DAM. All obstructions, wall embankments or barriers, together with their abutments and appurtenant works, if any, constructed for the purpose of storing or diverting water or creating a pool. DAMS may also include weirs, restrictive culverts or impoundment structures. Underground water storage tanks are not included.
DELEGATED COMMUNITY. A community delegated state permitting authority for construction in the floodway under 17 Ill. Adm. Part 3708 by IDNR/OWR.
DESIGNATED FLOODWAY.
(a) The channel, including on-stream lakes, and that portion of the floodplain adjacent to a stream or watercourse, generally depicted on the FEMA FIRM map, which is needed to store and convey the existing 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 10% increase in velocities.
(b) The floodway area designated for on the countywide FIRM of Cook County prepared by FEMA and listed in Appendix A of Ord. O-16-19, passed October 15, 2019. When two floodway maps exist for a waterway, the more recent effective floodway limit shall prevail.
(c) The floodways for those parts of unincorporated Cook County that are within the extraterritorial jurisdiction of the city that may be annexed into the city are designated on the countywide FIRM of Cook County prepared by FEMA and listed in Appendix A of Ord. O-16-19, passed October 15, 2019.
(d) To locate the DESIGNATED FLOODWAY boundary on any site, the DESIGNATED FLOODWAY boundary should be scaled off the FIRM map and located on a site plan, using reference marks common to both maps. Where interpretation is needed to determine the exact location of the DESIGNATED FLOODWAY boundary, IDNR/OWR should be contacted for the interpretation.
DETENTION BASIN. A man-made structure for the temporary storage of stormwater runoff with controlled release rate during and immediately following a storm.
DEVELOPMENT.
(a) Any man-made change to real estate, including:
1. Construction, reconstruction, repair, or placement of a Building or any addition to a building;
2. Substantial improvement of an existing building;
3. Installing a manufactured home on a site, preparing a site for a manufactured home, or installing a travel trailer or recreational vehicle on a site for more than 180 consecutive days. If a travel trailer or recreational vehicle is on site for more than 180 consecutive days it must be fully licensed and ready for highway use;
4. Installing utilities, construction of roads, bridges, or similar projects;
5. Demolition of a building, re-development of a site, clearing of land as an adjunct of construction;
6. Construction or erection of levees, walls, fences, dams, culverts, or channel modifications;
7. Filling, dredging, grading, excavating, paving, drilling, mining or other agricultural alterations of the ground surface;
8. Storage of materials including the placement of gas and liquid storage tanks, and any other activity that might change the direction, heights, or velocity of flood or surface waters;
9. Any other activity of man that might change the direction, heights, or velocity of flood or surface water, including extensive vegetation removal.
(b) DEVELOPMENT does not include such activities as re-surfacing of pavement when there is no increase in elevation, or gardening, plowing, and similar agricultural practices that do not involve filling, grading, or construction of levees.
ELEVATION CERTIFICATES. A form published by the Federal Emergency Management Agency that is used to certify the base flood elevation and the lowest elevation of usable space to which a building has been constructed.
EMERGENCY OVERFLOW. The structure in a detention or retention basin designed to protect the basin and direct excess flow from the basin to minimize impacts in the event of a malfunction of the primary outlet or a storm event greater than the basin design storm.
EROSION. The general process whereby soils are moved by flowing water or wave action.
EXCAVATION. Any act by which organic matter, earth, sand, gravel rock or any other similar material is cut into, dug, quarried, uncovered, removed, displaced, relocated or bulldozed. The term shall therefore include the conditions resulting therefrom.
EXCEPTIONAL FUNCTIONAL VALUE WETLAND. Any wetland that either (1) meets the Illinois Natural Area Inventory's definition for determining exceptional functional value or (2) is located in an Illinois Natural Area Inventory site.
EXEMPT ORGANIZATIONS. Organizations which are exempt from this chapter per the ILCS include state, federal, or local units of government such as the Metropolitan Water Reclamation District of Greater Chicago.
EXISTING GRADE. The vertical location of the existing ground surface prior to excavation or filling.
EXISTING MANUFACTURED HOME PARK OR SUBDIVISION. A manufactured home park or subdivision for which the construction of facilities for servicing the lots on which the manufactured homes are to be affixed or buildings to be constructed (including, at a minimum, the installation of utilities, the construction of streets, and either final site grading or the pouring of concrete pads) is completed before the effective date of the city’s initial floodplain management regulations.
EXPANSION TO AN EXISTING MANUFACTURED HOME PARK OR SUBDIVISION. The preparation of additional sites by the construction of facilities for servicing the lots on which the manufactured homes are to be affixed (including the installation of utilities, the construction of streets, and either final site grading or the pouring of concrete pads).
FEMA. Federal Emergency Management Agency and its regulations at 44 CFR 59-79 effective as of October 1, 1986. This incorporation does not include any later editions or amendments.
FLOOD.
(a) A general and temporary condition of partial or complete inundation of normally dry land areas from overflow of inland or tidal waters, or from the unusual and rapid accumulation or runoff of surface waters from any source.
(b) FLOOD also includes the collapse or subsidence of land along the shore of a lake or other body of water as a result of erosion or undermining caused by waves or currents of water exceeding anticipated cyclical levels or suddenly caused by an unusually high water level in a natural body of water, accompanied by a severe storm, or by an unanticipated force of nature, such as flash flood or abnormal tidal surge, or by some similarly unusual and unforeseeable event which results in a general and temporary condition of partial or complete inundation of normally dry land areas from the overflow of inland or tidal waters.
FLOOD FREQUENCY. A period of years based on a statistical analysis, during which a flood of a stated magnitude may be expected to be equaled or exceeded.
FLOOD FRINGE. That portion of the floodplain outside the designated floodway.
FLOOD INSURANCE RATE MAP (FIRM). A map prepared by FEMA that depicts the floodplain or special flood hazard area within a community. This map includes insurance rate zones and floodplains and may or may not depict floodways and show BFE.
FLOOD PROTECTION ELEVATION (FPE). The elevation of the base flood plus one foot of freeboard at any given location in the floodplain.
FLOODPLAIN (OR SPECIAL FLOOD HAZARD AREA (SFHA).
(a) For purpose of this chapter, these two terms are synonymous.
(b) Any land area susceptible to being inundated by water from any source.
(c) FLOODPLAIN also includes those areas of known flooding as identified by the community.
(d) The FLOODPLAINS are those lands within the jurisdiction of the city that are subject to inundation by the base flood. The FLOODPLAINS of the city are generally identified as such on panel number(s) listed in (Appendix A floodplain map panel number(s)) of the countywide FIRM for Cook County as prepared by the FEMA.
(e) The FLOODPLAINS of those parts of unincorporated Cook County that are within the extraterritorial jurisdiction of the city, or that may be annexed into the city, that are subject to inundation by the base flood. The FLOODPLAINS are generally identified as such on panel number(s) listed in (Appendix A) of the countywide FIRM for Cook County.
FLOODPROOFING. Any combination of structural and non-structural additions, changes or adjustments to buildings that reduce or eliminate flood damage to real estate or improved real property, water and sanitary facilities, buildings, and their contents.
FLOODPROOFING CERTIFICATE. A form published by the Federal Emergency Management Agency that is used to certify that a building has been designed and constructed to be structurally dry flood proofed to the flood protection elevation.
FLOODWAY. See DESIGNATED FLOODWAY.
FREEBOARD. An increment of elevation added to the BFE to provide a factor of safety for uncertainties in calculations, future watershed development, unknown localized conditions, wave actions and unpredictable effects such as those caused by ice or debris jams.
HISTORIC STRUCTURE. Any structure that is:
(a) Listed individually in the National Register of Historic Places or preliminarily determined by the Secretary of the Interior as meeting the requirements for individual listing on the National Register,
(b) Certified or preliminarily determined by the Secretary of the Interior as contributing to historic district or a district preliminarily determined by the Secretary to qualify as a registered historic district;
(c) Individually listed on the state inventory of historic places by the Illinois Historic Preservation Agency;
(d) Individually listed on a local inventory of historic places that has been certified by the Illinois Historic Preservation Agency.
HYDROLOGIC AND HYDRAULIC CALCULATIONS. Engineering analysis which determines expected flood flows and flood elevations based on land characteristics and rainfall events.
IDNR/OWR. The Illinois Department of Natural Resources, Office of Water Resources, the agency responsible for administering ILCS Ch. 615, Act 5, § 18(g), the River, Lakes and Streams Act.
LETTER OF MAP AMENDMENT (LOMA). Official determination by FEMA that a specific building, area of land or a parcel of land, where there has not been any alteration of the topography since the date of the first NFIP map showing the property within the floodplain, was inadvertently included within the floodplain and that the building, area of land or a parcel of land is removed from the floodplain.
LETTER OF MAP REVISION (LOMR). Letter that revises BFEs, floodplains or floodways as shown on an effective FIRM.
LOWEST FLOOR. The lowest floor of the lowest enclosed area (including basement). An unfinished or flood resistant enclosure usable solely for parking of vehicles, building access or storage, in an area other than a basement area is not considered a building’s LOWEST FLOOR; provided that such enclosure is not built so as to render the building in violation of the applicable non-elevation design requirements of this chapter.
MANUFACTURED HOME. A structure, transportable in one or more sections, which is built on a permanent chassis and is designed for use with or without a permanent foundation when attached to the required utilities. The term MANUFACTURED HOME does not include a recreational vehicle.
MANUFACTURED HOME PARK OF SUBDIVISION. A parcel (or contiguous parcels) of land divided into two or more manufactured home lots for rent or sale.
MINOR DRAINAGE SYSTEM. That portion of a drainage system designed to safely convey the 10-year storm event or less. It includes street gutters, storm sewers, small open channels, and swales.
MITIGATION. Mitigation includes those measures necessary to minimize the negative effects which flood plain development activities might have on the public health, safety and welfare. Examples of mitigation include compensatory storage, soil erosion and sedimentation control, and streambank restoration.
MWRDGC. The Metropolitan Water Reclamation District of Greater Chicago.
NATIONAL GEODETIC VERTICAL DATUM OF 1929 (NGVD). Reference surface set by the National Geodetic Survey deduced from a continental adjustment of all existing adjustment in 1929.
NATURAL. When used in reference to channels means those channels formed by the existing surface topography of the earth prior to changes made by man. A natural stream tends to follow a meandering path; its flood plain is not contained by levees; the area near the bank has not been cleared, mowed or cultivated; the stream flows over soil and geologic minerals typical of the area with no substantial alteration of the course or cross-section of the stream caused by filling or excavating. A modified channel may regain some natural characteristics over time as the channel meanders and vegetation is re-established. Similarly, a modified channel may be restored to more natural conditions by man through regrading and revegetation.
NAVD 88. North American Vertical Datum of 1988. NAVD 88 supersedes the National Geodetic Vertical Datum of 1929 (NGVD).
NEW MANUFACTURED HOME PARK OR SUBDIVISION. Manufactured home park or subdivision for which the construction of facilities for servicing the lots on which the manufactured homes are to be affixed (including at a minimum, the installation of utilities, the construction of streets, and either final site grading or the pouring of concrete pads) is completed on or after the effective date of the city’s initial floodplain management regulations.
ORDINARY HIGH WATER MARK (OHWM). The point on the bank or shore up to which the presence and action of surface water is so continuous so as to leave a distinctive mark such as by erosion, destruction or prevention of terrestrial vegetation, predominance of aquatic vegetation or other easily recognized characteristics.
OVERLAND FLOW PATH. An area of land which conveys stormwater for all events up to and including the base flood event. The overland flow path can be determined using topographical information and shall take into account all on-site and off-site tributary areas.
PUBLIC BODY OF WATER. All open public streams and lakes capable of being navigated by watercraft, in whole or in part, for commercial uses and purposes, and all lakes, rivers, and streams which in their natural condition were capable of being improved and made navigable lakes or rivers within, or upon the borders of the State of Illinois, together with all bayous, sloughs, backwaters, and submerged lands that are open to the main channel or body of water directly accessible thereto, as identified in 17 Ill. Adm. Code Part 3704.
PUBLIC FLOOD CONTROL PROJECT. A flood control project which will be operated and maintained by a public agency to reduce flood damages to existing buildings and structures which includes a hydrologic and hydraulic study of the existing and proposed conditions of the watershed. Nothing in this definition shall preclude the design, engineering, construction or financing, in whole or in part, of a flood control project by persons or parties who are not public agencies.
PUBLIC NAVIGABLE WATERS. All streams and lakes capable of being navigated by watercraft.
RECREATIONAL VEHICLE OR TRAVEL TRAILER. A vehicle which is:
(a) Built on a single chassis;
(b) 400 square feet or less when measured at the largest horizontal projection;
(c) Designed to be self-propelled or permanently towable by a light duty truck; and
(d) Designed primarily not for use as a permanent dwelling but as temporary living quarters for recreational, camping, travel, or seasonal use.
REGIONAL PERMITS. Offered for pre-approved projects which are considered minor projects that are permissible per IDNR/OWR Part 3708 rules for Northeastern Illinois designated floodways. A complete listing of the terms and conditions for specific project types can be obtained from the IDNR/OWR website.
REGISTERED LAND SURVEYOR. A land surveyor registered in the state under The Illinois Land Surveyors Act.
REGISTERED PROFESSIONAL ENGINEER. An engineer registered in the state under The Illinois Professional Engineering Act.
REPAIR, REMODELING, OR MAINTENANCE. Development activities which do not result in any increases in the outside dimensions of a building or any changes to the dimensions of a structure.
REPETITIVE LOSS. Flood-related damages sustained by a building on two separate occasions during a ten-year period for which the cost of repairs at the time of each such flood event, on the average, equals or exceeds 25% of the market value of the building before the damage occurred.
RETENTION/DETENTION FACILITY. A retention facility stores stormwater runoff without a gravity release. A detention facility provides for storage of stormwater runoff and controlled release of this runoff during and after a flood or storm.
RIVERINE FLOODPLAIN. Any floodplain or 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.
RIVERINE SFHA. Any SFHA subject to flooding from a river, creek, intermittent stream, ditch, on stream lake system or any other identified channel. This term does not include areas subject to flooding from lakes, ponding areas, areas of sheet flow, or other areas not subject to overbank flooding.
RUNOFF. The water derived from melting snow or rain falling on the land surface, flowing over the surface of the ground or collected in channels or conduits.
SEDIMENTATION. The processes that deposit soils, debris, and other materials either on other ground surfaces or in bodies of water or watercourses.
SPECIAL FLOOD HAZARD AREA (SFHA). See FLOODPLAIN.
START OF CONSTRUCTION. Includes substantial improvement and means the date the building permit was issued, provided the actual start of construction, repair, reconstruction, rehabilitation, addition placement or other improvement, was within 180 days of the permit date. The ACTUAL START means either the first placement of permanent construction of a building on a site, such as the pouring of slab or footings, the installation of piles, the construction of columns or any work beyond the state of excavation or the placement of a manufactured home on a foundation. For a substantial improvement, ACTUAL START OF CONSTRUCTION means the first alteration of any wall, ceiling, floor or other structural part of a building whether or not that alteration affects the external dimensions of the building.
STRUCTURE. The results of a man-made 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 a manufactured home on a site; preparing a site for a manufactured home or installing a travel trailer on a site for more than 180 days, unless they are fully licensed and ready for highway use.
SUBSTANTIAL IMPROVEMENT. Any repair, reconstruction, rehabilitation, addition or improvement of a structure, the cost of which equals or exceeds 50% of the market value of the structure either, (a) before the improvement of 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 pre-damaged condition would equal or exceed 50% of the market value before the damage occurred, regardless of the actual repair work performed. For the purpose of this definition, substantial improvement is considered to occur when the first alteration of any wall, ceiling, floor, or other structural parts of a building commences, whether or not that alteration affects the external dimensions of the structure. The term does not, however, include either any project for improvement of a structure to comply with any existing state or local health, sanitary, or safety code specifications which are solely necessary to assure safe living conditions or any alteration of a historic structure, provided that the alteration will not preclude the structure's continued designation as a historic structure.
TRANSITION SECTION. Reaches of the stream of floodway where water flows from a narrow cross-section to a wide cross-section or vice versa.
WATERS OF THE UNITED STATES. Those waters under the authority of the Corps of Engineers under the Clean Water Act and defined in 33 CFR Part 328, as amended. This includes most lakes, rivers, streams, ponds, and wetlands.
WATERSHED. All land area drained by, or contributing water to, the same stream, lake, or stormwater facility.
WETLAND. A wetland is land that is inundated or saturated by surface or ground water at a frequency and duration sufficient to support, under normal conditions, a prevalence of vegetation adapted for life in saturated soil conditions (known as hydrophytic vegetation). A wetland is identified based on three attributes: 1) hydrology, 2) soils, and 3) vegetation as mandated by the federal wetland determination methodology.
WETLAND IMPACT. Any development activity within the boundary of a delineated wetland. Final determination of wetland impact is performed by the U.S. Environmental Protection Agency and the U.S. Corps of Engineers based on 33 CFR Part 320-Section 404(b)(1) and 33 CFR Parts 320 through 330, as amended.
(Ord. 92-23, passed 6-16-92; amend. Ord. O-13-97, passed 6-3- 97; amend. Ord. O-7-01, passed 1-16-01); amend. Ord. O-14-03, passed 2-18-03; amend. Ord. O-19-08, passed 8-5-08; amend. Ord. O-16-19, passed 10-15-19)