For the purpose of this chapter, the following definitions are adopted:
ACCESSORY STRUCTURE: A nonhabitable structure which is on the same parcel of property as the principal structure to be insured and the use of which is incidental to the use of the principal structure.
ACT: An act in relation to the regulation of the rivers, lakes and streams of the state of Illinois, 615 Illinois Compiled Statutes 5/5 et seq.
APPLICANT: Any person, firm, corporation or agency which submits an application.
APPROPRIATE USE: Only uses of the designated floodway are permissible and will be considered for permit issuance. The only uses that will be allowed are as specified in subsection 14-1-7B 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 defined in section 14-1-5 of this chapter.
BASE FLOOD ELEVATION (BFE): The elevation in relation to mean sea level of the crest of the base flood.
BASEMENT: That portion of the building having its floor subgrade (below ground level) on all sides.
BUILDING: A structure that is principally aboveground and is enclosed by walls and a roof. This 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 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 DESIGNATED FLOODWAY MAP CHANGE: Preconstruction approval by IDNR/OWR and FEMA 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 FEMA will revise base flood elevations, flood insurance rate zones, flood boundaries or floodway as shown on an effective flood hazard boundary map or flood insurance rate map, once the as built plans are submitted and approved.
CONTROL STRUCTURE: A structure designed to control the rate of flow that passes through the structure, given a specific upstream and downstream water surface elevation.
CRITICAL FACILITY: Any facility which is critical to the health and welfare of the population and, if flooded, would create an added dimension to the disaster. Damage to these critical facilities can impact the delivery of vital services, can cause greater damage to other sectors of the community, or can put special populations at risk. Examples of critical facilities where flood protection should be required include emergency services facilities (such as fire and police stations), schools, hospitals, retirement homes and senior care facilities, major roads and bridges, critical utility sites (telephone switching stations or electrical transformers), and hazardous material storage facilities (chemicals, petrochemicals, hazardous or toxic substances). Examples of critical facilities where flood protection is recommended include sewage treatment plants, water treatment plants, and pumping stations.
DAM: All obstructions, wall embankments or barriers, together with their abutments and appurtenant works, if any, constructed for the purpose of storing or diverting water or creating a pool. Dams may also include weirs, restrictive culverts or impoundment structures. Underground water storage tanks are not included.
DESIGNATED FLOODWAY: The channel, including on stream lakes, and that portion of the floodplain adjacent to a stream or watercourse, generally depicted on the FEMA FIRM map, which is needed to store and convey the existing 100-year frequency flood discharge with no more than a 0.1 foot increase in stage due to the loss of flood conveyance or storage, and no more than a 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 Des Plaines that may be annexed into the city of Des Plaines are designated for the Des Plaines River, Prairie Creek, Farmers Creek, Willow Creek, Weller Creek, and Feehanville Ditch 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.
DETACHED SINGLE-FAMILY GARAGE AND SHED: A structure or structures used for the storage of motor vehicles or other storage incidental to the principal use and which is independent, freestanding and not structurally attached to the principal structure.
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 or recreational vehicle on a site for more than one hundred eighty (180) days. If the travel trailer or recreational vehicle is on site for more than one hundred eighty (180) days, it must be fully licensed and ready for highway use;
C. Drilling, mining, installing utilities, construction of roads, bridges, or similar projects;
D. Demolition of a structure or redevelopment of a site;
E. Clearing of land as an adjunct of construction;
F. Construction or erection of levees, walls, fences, dams, or culverts; channel modification; filling, dredging, grading, excavating, paving, or other 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;
H. Substantial improvement of an existing building;
I. Development does not include routine maintenance of existing buildings and facilities such as reroofing or resurfacing of roads or driveway replacement 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 FEMA that is used to certify the elevation to which a building has been elevated. Required with any development within the 100-year floodplain that requires the issuance of a building permit by the city or as directed by the director of public works and engineering.
EROSION: The general process whereby soils are moved by flowing water or wave action.
EXEMPT ORGANIZATIONS: Organizations which are exempt from this chapter per Illinois Compiled Statutes including state, federal or local units of government.
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 (including, at a minimum, the installation of utilities, the construction of streets, and either final site grading or the pouring of concrete pads) has been completed before April 1, 1990.
EXPANSION TO AN EXISTING MANUFACTURED HOME PARK OR SUBDIVISION: The preparation of additional sites by the construction of facilities for servicing the lots on which the manufactured homes are to be affixed (including the installation of utilities, the construction of streets, and either final site grading or the pouring of concrete pads).
FEMA: Federal emergency management agency and its regulations at 44 CFR 59 - 79, as amended.
FLOOD: A general and temporary condition of partial or complete inundation of normally dry land areas from overflow of inland or tidal waves, or the unusual and rapid accumulation or runoff of surface waters from any source.
FLOOD FREQUENCY: A period of years, based on a statistical analysis, during which a flood of a stated magnitude may be expected to be equaled or exceeded.
FLOOD FRINGE: That portion of the floodplain outside of the regulatory floodway.
FLOOD INSURANCE RATE MAP (FIRM): A map prepared by FEMA that depicts the special flood hazard area (SFHA) within a community. This map includes insurance rate zones and floodplains and may or may not depict floodways.
FLOOD INSURANCE STUDY (FIS): An examination, evaluation and determination of flood hazards and, if appropriate, corresponding water surface elevations.
FLOOD PROTECTION ELEVATION (FPE): The elevation of the base flood or 100-year frequency floods plus two feet (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). 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 of Des Plaines are generally identified as such on map 17031C panels 0208J, 0209J, 0212J, 0214J, 0216J, 0217J, 0218J, 0219J, 0236J, 0238J, 0356J, 0357J, 0376J dated August 19, 2008, respectively, of the countywide flood insurance rate map for Cook County prepared by the federal emergency management agency.
The SFHAs for those parts of unincorporated Cook County that are within the one and one-half (11/2) mile extraterritorial jurisdiction of Des Plaines and may be annexed into the city of Des Plaines are designated for Weller Creek, Des Plaines River, Prairie Creek and Farmers Creek on map 17031C and panels 0207J, 0228J, 0229J dated August 19, 2008, respectively, of the countywide flood insurance rate map for Cook County prepared by the federal emergency management agency.
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.
FLOODWAY: See definition of Designated Floodway.
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 the 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.
HYDRAULICALLY EQUIVALENT COMPENSATORY STORAGE: Compensatory storage that can be shown by hydrologic and hydraulic analysis to offset the increase in flood elevations caused by a development.
HYDROLOGIC AND HYDRAULIC CALCULATIONS: Engineering analysis, which determines 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 AMENDMENTS (LOMA): Official determination by FEMA that a specific structure is not in a 100-year flood zone; amends the effective 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 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 structure in violation of the applicable nonelevation design requirements of this chapter.
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) days. The term "manufactured home" does not include a "recreational vehicle".
MANUFACTURED HOME PARK OR SUBDIVISION: A parcel (or contiguous parcels) of land divided into two (2) or more manufactured home lots for rent or sale.
MARKET VALUE: Current value of building only, as determined by an Illinois licensed appraiser.
MITIGATION: Includes those measures necessary to minimize the negative effects which floodplain development activities might have on the public health, safety and welfare. Examples of mitigation include excavation of compensatory storage, soil erosion, sedimentation control, and channel restoration. Mitigation may also include those activities taken to reduce a structure's susceptibility to flooding.
NAVD 88: National American vertical datum of 1988. NAVD 88 supersedes the national geodetic vertical datum of 1929 (NGVD).
NATURAL: When used in reference to channels means those channels formed by the existing surface topography of the earth prior to changes made by man. A natural stream tends to follow a meandering path; its floodplain is not constrained by levees; the area near the bank has not been cleared, mowed or cultivated; the stream flows over soil and geologic materials typical of the area with no substantial alteration of the course or cross section of the stream caused by filling or excavating. A modified channel may regain some natural characteristics over time as the channel meanders and vegetation is reestablished. Similarly, a modified channel may be restored to more natural conditions by man through regrading and revegetation.
NEW CONSTRUCTION: Structures for which the start of construction commenced on or after the effective date of a floodplain management regulation adopted by a community and includes any subsequent improvements to such structures.
OWR: Illinois department of natural resources, office of water resources.
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 BODIES OF WATERS: All open public streams and lakes capable of being navigated by watercraft, in whole or in part, for commercial uses and purposes, and all lakes, rivers, and streams which in their natural condition were capable of being improved and made navigable, or that are connected with or discharge their waters into navigable lakes or rivers within, or upon the borders of the state of Illinois, together with all bayous, sloughs, backwaters, and submerged lands that are open to the main channel or body of water directly accessible thereto.
PUBLIC FLOOD CONTROL PROJECT: A flood control project, which will be operated and maintained by a public agency to reduce flood damages to existing buildings and structures, including a hydrologic and hydraulic study of the existing and proposed conditions of the watershed. Nothing in this definition shall preclude the design, engineering, construction or financing, in whole or in part, of a flood control project by persons or parties who are not public agencies.
RECREATIONAL VEHICLE OR TRAVEL TRAILER: A vehicle, which is:
A. Built on a single chassis.
B. Four hundred (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.
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 preapproved 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 of Illinois, under the Illinois land surveyors act.
REGISTERED OR LICENSED PROFESSIONAL ENGINEER: An engineer registered in the state of Illinois, under the Illinois professional engineering practice act.
REGULATORY FLOODWAY: See definition of Designated Floodway.
REPAIR, REMODELING OR MAINTENANCE: Developing activities which do not result in any increases in the outside dimensions of a building or any changes to the dimensions of a structure.
REPETITIVE LOSS: Flood related damages sustained by a structure on two (2) separate occasions during a ten (10) year period for which the cost of repairs at the time of each such flood event, on the average, equals or exceeds twenty five percent (25%) of the market value of the structure 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 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 definition of 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 one hundred eighty (180) days of the permit date. The "actual start" means either the first placement of permanent construction of a structure on a site, such as the pouring of slab or footings, the installation of piles, the construction of columns, or any work beyond the stage of excavation; or placement of a manufactured home on a foundation.
STATEWIDE PERMITS: Offered for preapproved projects that are considered minor projects, which are permissible per the IDNR/OWR part 3700 rules. A complete listing of the statewide permits and permit requirements can be obtained from the IDNR/OWR website.
STRUCTURE: 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 DAMAGE: Damage of any origin sustained by a structure whereby the cumulative percentage of damage incurred during a ten (10) year period measured from the date of the most recent damage, and dating back to no earlier than January 1, 2009 (the effective date of this title), equals or exceeds fifty percent (50%) of the market value of the structure before the damage occurred, regardless of actual value of the repair work performed. The value of volunteer labor, donated materials, and other in-kind contributions, must be included in the calculation of substantial damage. This term includes repetitive loss buildings. (See definition of Repetitive Loss.)
SUBSTANTIAL IMPROVEMENT: Any repair, reconstruction, rehabilitation, addition, or improvement of a structure taking place during a ten (10) year period measured from the date of the most recent damage, and dating back to no earlier than January 1, 2009 (the effective date of this title), in which the cumulative percentage of improvements equals or exceeds fifty percent (50%) of the market value of the structure before the improvement or repair is conducted or installed. The value of volunteer labor, donated materials, and other in-kind contributions, must be included in the calculation of substantial improvement.
A. "Substantial improvement" is considered to occur when the first alteration of any wall, ceiling, floor, or other structural part of the building commences, whether or not that alteration affects the external dimensions of the building. This term includes structures, which have incurred repetitive loss or substantial damage, regardless of the actual work done.
B. "Substantial improvement" does not, however, include any project for improvement of a structure to comply with existing federal, state, or local health, sanitary, or safety code specifications that are solely necessary to assure safe living conditions.
TRANSITION SECTION: Reaches of the stream or floodway where water flows from a narrow cross section to a wide cross section or vice versa.
VIOLATION: The failure of a structure or other development to be fully compliant with the community's floodplain management regulations. A structure or other development without the elevation certificate, other certifications, or other evidence of compliance is presumed to be in violation until such time as that documentation is provided. (Ord. M-15-16, 6-6-2016)