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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 of Illinois, 615 Illinois Compiled Statutes 5/4.9 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 13-2-7 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 13-2-5 of this chapter.
BUILDING: A structure that is principally aboveground and is enclosed by walls and a roof. The term includes a gas or liquid storage tank, a manufactured home, a mobile home or a prefabricated building. This 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 floodplain. The uncompensated loss of natural floodplain storage can increase off site floodwater elevations and flows.
CONDITIONAL APPROVAL OF A REGULATORY FLOODWAY MAP CHANGE: Preconstruction approval by IDNR/OWR and the federal emergency management agency of a proposed change to the floodway map. This preconstruction approval, pursuant hereto, 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, 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.
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.
DEVELOPMENT: A. Any manmade change to real estate, including:
1. Construction, reconstruction, repair, or placement of a building or any addition to a building.
2. 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.
3. Drilling, mining, installing utilities, construction of roads, bridges, or similar projects.
4. Demolition of a structure or redevelopment of a site.
5. Clearing of land as an adjunct of construction.
6. 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.
7. Any other activity of man that might change the direction, height, or velocity of flood or surface water, including extensive vegetation removal.
B. 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 CERTIFICATE: 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 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 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 MAP (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 three feet (3') 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). The floodplains are those lands within the jurisdiction of the village that are subject to inundation by the base flood or 100-year frequency flood. The SFHAs of the village are generally identified as such on the flood insurance rate map of the village prepared by the federal emergency management agency and dated January 1, 1982 (as may be amended). The SFHAs of those parts of unincorporated DuPage County that are within the extraterritorial jurisdiction of the village or that may be annexed into the village are generally identified as such on the flood insurance rate map prepared for DuPage County by the federal emergency management agency and dated April 15, 1982.
FLOODPROOFING: Any combination of structural and nonstructural additions, changes or adjustments to structures which reduces or eliminates 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 action and unpredictable effects such as those caused by ice or debris jams.
HYDROLOGIC AND HYDRAULIC CALCULATIONS: Engineering analyses which determine expected flood flows and flood elevations based on land characteristics and rainfall events.
IDNR/OWR: Illinois department of natural resources, office of water resources.
LETTER OF MAP AMENDMENT (LOMA): Official determination by FEMA that a specific structure is not in a 100-year 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 is designated for use with or without a permanent foundation when connected to the required utilities. The term manufactured home also includes park trailers, travel trailers and other similar vehicles placed on site for more than 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: 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.
ORDINARY HIGH WATER MARK (OHWM): The point on the bank or shore up to which the presence and action of surface water is so continuous so as to leave a distinctive mark such as by erosion, destruction or prevention of terrestrial vegetation, predominance of aquatic vegetation or other easily recognized characteristics.
PUBLIC FLOOD CONTROL PROJECT: A flood control project which will be operated and maintained by a public agency to reduce flood damages to existing buildings and structures 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.
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 surveyor act, 225 Illinois Compiled Statutes 330/1 et seq.
REGISTERED PROFESSIONAL ENGINEER: An engineer registered in the state of Illinois under the Illinois professional engineering practice act, 225 Illinois Compiled Statutes 325/1 et seq.
REGULATORY FLOODWAY: The channel, including on stream lakes, and that portion of the floodplain adjacent to a stream or watercourse as designated by IDNR/OWR, which is needed to store and convey the existing and anticipated future 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. The regulatory floodways are designated for Armitage Creek on the regulatory floodplain map prepared by FEMA and dated December 16, 2004. The regulatory floodways for those parts of unincorporated DuPage County that are within the extraterritorial jurisdiction of the village that may be annexed into the village are designated for Armitage Creek on the flood boundary and floodway map prepared by FEMA and dated December 16, 2004. 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 dimension 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 or the ground or collected in channels or conduits.
SEDIMENTATION: The processes that deposit soil, debris, and other materials either on other ground surfaces or in bodies of water or watercourses.
SPECIAL FLOOD HAZARD AREA (SFHA): 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, AR, AE, A99, AH, VE, V, X, or D.
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. (Prior ord.; amd. Ord. 2004-49, 6-17-2004; 2011 Code)