For the purpose of this Chapter, the following definitions are adopted:
ACT: "An Act" in relation to the regulation of the rivers, lakes and streams of the State, 615 Illinois Compiled Statutes 5/5 et seq.
APPLICANT: Any person, firm, corporation or agency which submits an application.
APPROPRIATE USE: 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 Section 7-1-8-2 of this Chapter.
BASE FLOOD: The flood having a one percent (1%) probability of being equaled or exceeded in any given year. The base flood is also known as the 100-year frequency flood event. Application of the base flood elevation at any location is as defined in Section 7-1-6 of this Chapter.
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. The term also includes recreational vehicles and travel trailers to be installed on a site for more than one hundred eighty (180) days.
CHANNEL: Any river, stream, creek, brook, branch, natural or artificial depression, ponded area, flowage, slough, ditch, conduit, culvert, gully, ravine, wash or natural or manmade drainageway, which has a definite bed and banks or shoreline, in or into which surface or ground water 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, riprapping or other armoring, widening, deepening, straightening, relocating, lining and significant removal of bottom or woody vegetation. Channel modification does not include the clearing of dead or dying vegetation, debris, or trash from the channel. Channelization is a severe form of channel modification typically involving relocation of the existing channel (e.g., straightening).
COMPENSATORY STORAGE: An artificially excavated, hydraulically equivalent volume of storage within the SFHA used to balance the loss of natural flood storage capacity when artificial fill or structures are placed within the flood plain. The uncompensated loss of natural flood plain storage can increase off-site floodwater elevations and flows.
CONDITIONAL APPROVAL OF A REGULATORY FLOODWAY MAP CHANGE: Preconstruction approval by DWR and the Federal Emergency Management Agency of a proposed change to the Floodway Map. This preconstruction approval, pursuant to this Chapter, gives assurances to the property owner that once an appropriate use is constructed according to permitted plans, the Floodway Map can be changed, as previously agreed, upon review and acceptance of as-built plans.
CONDITIONAL LETTER OF MAP REVISION (CLOMR): A letter which indicates that the Federal Emergency Management Agency will revise base flood elevations, flood insurance rate zones, flood boundaries or floodway as shown on an effective Flood Hazard Boundary Map or Flood Insurance Rate Map, once the as- built plans are submitted and approved.
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.
DWR: Illinois department of natural resources, office of water resources.
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. Underground water storage tanks are not included.
DESIGNATED FLOODWAY: The channel, including on stream lakes, and that portion of the floodplain adjacent to a stream or watercourse, generally depicted on the FEMA FIRM, which is needed to store and convey the existing 100-year frequency flood discharge with no more than a 0.1 foot increase in stage due to the loss of flood conveyance or storage, and no more than a ten percent (10%) increase in velocities.
A.The floodways are designated for on the countywide flood insurance rate map of Cook County prepared by FEMA and dated August 19, 2008. When two (2) floodway maps exist for a waterway, the more restrictive floodway limit shall prevail.
B.The floodways for those parts of unincorporated Cook County that are within the extraterritorial jurisdiction of the city of Prospect Heights that may be annexed into the city are designated for McDonald Creek and the Des Plaines River on the countywide flood insurance rate map prepared by FEMA and dated August 19, 2008.
C.To locate the designated floodway boundary on any site, the designated floodway boundary should be scaled off the designated floodway map and located on a site plan, using reference marks common to both maps. Where interpretation is needed to determine the exact location of the designated floodway boundary, IDNR/OWR should be contacted for the interpretation.
DEVELOPMENT: Any manmade change to real estate, including:
A.Construction, reconstruction, repair or placement of a building or any addition to a building.
B.Installing a manufactured home on a site, preparing a site for a manufactured home, or installing a travel trailer on a site for more than one hundred eighty (180) days.
C.Drilling, mining, installing utilities, construction of roads, bridges or similar projects.
D.Demolition of a structure or redevelopment of a site.
E.Clearing of land as an adjunct of construction.
F.Construction or erection of levees, walls, fences, dams, or culverts; channel modification; filling, dredging, grading, excavating, paving, or other nonagricultural alterations of the ground surface; storage of materials; deposit of solid or liquid waste.
G.Any other activity of man that might change the direction, height, or velocity of flood or surface water, including extensive vegetation removal.
Development does not include maintenance of existing buildings and facilities such as reroofing or resurfacing of roads when there is no increase in elevation, or gardening, plowing, and similar agricultural practices that do not involve filling, grading, or construction of levees.
ELEVATION CERTIFICATES: A form published by the federal emergency management agency that is used to certify the elevation to which a building has been elevated.
EROSION: The general process whereby the soils are moved by flowing water or wave action.
EXEMPT ORGANIZATIONS: Organizations which are exempt from this chapter per the Illinois Compiled Statutes including state, federal or local units of government.
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 general and temporary condition of partial or complete inundation of normally dry land areas from overflow of inland or tidal waves, or the unusual and rapid accumulation or runoff of surface waters from any source.
FLOOD FREQUENCY: A period of years, based on a statistical analysis, during which a flood of a stated magnitude may be expected to be equaled or exceeded.
FLOOD FRINGE: That portion of the floodplain outside of the regulatory floodway.
FLOOD INSURANCE RATE MAPS (FIRM): A map prepared by the federal emergency management agency that depicts the special flood hazard area (SFHA) within a community. This map includes insurance rate zones and floodplains and may or may not depict floodways.
FLOOD PROTECTION ELEVATION (FPE): The elevation of the base flood or 100-year frequency flood plus two and one-half feet (21/2') of freeboard at any given location in the SFHA.
FLOODPLAIN: That land typically adjacent to a body of water with ground surface elevations at or below the base flood or the 100-year frequency flood elevation. Floodplains may also include detached special flood hazard areas, ponding areas, etc. The floodplain is also known as the special flood hazard area (SFHA).
A.The floodplains are those lands within the jurisdiction of the city that are subject to inundation by the base flood or 100-year frequency flood. The SFHAs of the city are generally identified as such on panel numbers 0201, 0202, 0206, 0207, 0208 of the countywide flood insurance rate map of the city prepared by the federal emergency management agency and dated August 19, 2008.
B.The SFHAs of those parts of unincorporated Cook County that are within the extraterritorial jurisdiction of the city or that may be annexed into the city are generally identified as such on panel numbers 0201, 0202, 0206, 0207, 0208 of the countywide flood insurance rate map prepared for Cook County by the federal emergency management agency and dated August 19, 2008.
FLOODPROOFING: Any combination of structural and nonstructural additions, changes or adjustments to structures which reduce or eliminate flood damage to real estate or improved real property, water and sanitary facilities, structures and their contents.
FLOODPROOFING CERTIFICATE: A form published by the federal emergency management agency that is used to certify that a building has been designed and constructed to be structurally dry floodproofed to the flood protection elevation.
FREEBOARD: An increment of elevation added to the base flood elevation to provide a factor of safety for uncertainties in calculations, unknown localized conditions, wave actions and unpredictable effects such as those caused by ice or debris jams.
HYDROLOGIC AND HYDRAULIC CALCULATIONS: Engineering analysis which determines expected flood flows and flood elevations based on land characteristics and rainfall events.
LETTER OF MAP AMENDMENT (LOMA): Official determination by FEMA that a specific structure is not in a 100-year flood zone; amends the effective flood hazard boundary map or FIRM.
LETTER OF MAP REVISION (LOMR): Letter that revises base flood or 100-year frequency flood elevations, flood insurance rate zones, flood boundaries or floodways as shown on an effective FHBM or FIRM.
MANUFACTURED HOME: A structure, transportable in one or more sections, which is built on a permanent chassis and designed to be used with or without a permanent foundation when connected to the required utilities. The term manufactured homes also includes park trailers, travel trailers and other similar vehicles placed on a site for more than one hundred eighty (180) consecutive days.
MANUFACTURED HOME PARK OR SUBDIVISION: A parcel (or contiguous parcels) of land divided into two (2) or more manufactured home lots for rent or sale.
MITIGATION: Includes those measures necessary to minimize the negative effects which floodplain development activities might have on the public health, safety and welfare. Examples of mitigation include compensatory storage, soil erosion and sedimentation control, and channel restoration.
NGVD: National geodetic vertical datum of 1929. Reference surface set by the national geodetic survey deduced from a continental adjustment of all existing adjustments 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 floodplain is not constrained by levees; the area near the bank has not been cleared, mowed or cultivated; the stream flows over soil and geologic materials typical of the area with no substantial alteration of the course or cross section of the stream caused by filling or excavating. A modified channel may regain some natural characteristics over time as the channel meanders and vegetation is reestablished. Similarly, a modified channel may be restored to more natural conditions by man through regrading and revegetation.
OHWM (ORDINARY HIGH WATER MARK): The point on the bank or shore up to which the presence and action of surface water is so continuous so as to leave a distinctive mark such as by erosion, destruction or prevention of terrestrial vegetation, predominance of aquatic vegetation or other easily recognized characteristics.
PUBLIC FLOOD CONTROL PROJECT: A flood control project which will be operated and maintained by a public agency to reduce flood damages to existing buildings and structures 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 part, of a flood control project by persons or parties who are not public agencies.
PUBLICLY NAVIGABLE WATERS: All streams and lakes capable of being navigated by watercraft.
REGISTERED LAND SURVEYOR: A land surveyor registered in the state of Illinois, under the Illinois land surveyors act 1 .
REGISTERED PROFESSIONAL ENGINEER: An engineer registered in the state of Illinois, under the Illinois professional engineering act 2 .
REGULATORY FLOODWAY: The channel, including on stream lakes and that portion of the floodplain adjacent to a stream or watercourse as designated by DWR, which is needed to store and convey the existing and anticipated future 100-year frequency flood discharge with no more than a one-tenth foot (0.1') increase in stage due to the loss of flood conveyance or storage, and no more than a ten percent (10%) increase in velocities.
The regulatory floodways are designated for the McDonald Creek and its tributaries on map number 17031C and panels 0201F, 0202F, 0206F, 0207F and 0208F dated November 6, 2000, of the countywide flood insurance rate map for Cook County prepared by FEMA and the regulatory floodplain map prepared by DWR and dated October 1, 1978. The regulatory floodways for those parts of unincorporated Cook County that are within the extraterritorial jurisdiction of the city that have been or may be annexed into the city are designated for the Des Plaines River and McDonald Creek and its tributaries on map number 17031C and panels 0069F and 0226F, November 6, 2000, of the countywide flood insurance rate map for Cook County prepared by FEMA and the regulatory floodplain map prepared by DWR and dated October 1, 1978. 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, the division should be contacted for the interpretation.
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.
RETENTION/DETENTION FACILITY: A retention facility stores stormwater runoff without a gravity release. A detention facility provides for storage of stormwater runoff and controlled release of this runoff during and after a flood or storm.
RIVERINE SFHA: Any SFHA subject to flooding from a river, creek, intermittent stream, ditch, on stream lake system or any other identified channel. This term does not include areas subject to flooding from lakes, ponding areas, areas of sheet flow, or other areas not subject to overbank flooding.
RUNOFF: The water derived from melting snow or rain falling on the land surface, flowing over the surface of the ground or collected in channels or conduits.
SFHA (SPECIAL FLOOD HAZARD AREA): Any base flood area subject to flooding from a river, creek, intermittent stream, ditch, or any other identified channel or ponding and shown on a flood hazard boundary map or flood insurance rate map as zone A, AO, A1-30, AE, A99, AH, VO, V30, VE, V, M, or E.
SEDIMENTATION: The process that deposits soils, debris, and other materials either on other ground surfaces or in bodies of water or watercourses.
STRUCTURE: 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 a 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 (180) days.
SUBSTANTIAL IMPROVEMENT: Any repair, reconstruction or improvement of a structure, the cost of which equals or exceeds fifty percent (50%) of the market value of the structure either: a) before the improvement or repair is started, or b) if the structure has been damaged, and is being restored, before the damage occurred.
For the purposes of this definition "substantial improvement" is considered to occur when the first alteration of any wall, ceiling, floor, or other structural part of the building commences, whether or not that alteration affects the external dimensions of the structure.
The term does not, however, include either: a) any project for improvement of a structure to comply with existing state or local health, sanitary, or safety code specifications which are solely necessary to assure safe living conditions, or b) any alteration of a structure listed on the national register of historic places or a state inventory of historic places.
TRANSITION SECTION: Reaches of the stream or floodway where water flows from a narrow cross section to a wide cross section or vice versa. (Ord. 0-90-37, 8-20-1990; amd. Ord. 0-00-27, 10-16-2000, eff. 10-26-2000; Ord. 0-08-27, 7-8-2008, eff. 7-19-2008)
Notes
| 1 | 1. 225 ILCS 330/1 et seq. |
| 2 | 2. 225 ILCS 325/1 et seq. |