15.68.020   Definitions.
   Terms used in this chapter mean as follows:
   "Act" means "An Act in Relation to the Regulation of the Rivers, Lakes and Streams of the State of Illinois," Illinois Revised Statutes 1991, Chapter 19, Paragraph 52, et seq.
   "Applicant" means any person, firm, corporation or agency which submits an application pursuant to this chapter.
   "Appropriate use" means a use of the regulatory floodway that is listed in 17 Illinois Administrative Code 3708 and that will not cause a rise in the base flood elevation and will not create a damaging or potentially damaging increase in flood heights or velocity or be a threat to public health and safety. Approved appropriate uses are specified in Section 15.68.060(D) of this chapter.
   “Average Lot Grade” means the mathematical average of the ground elevation as measured at all of the corners of the buildable area of a parcel of land.  As used in this definition, the term “buildable area” shall have the same definition as provided in Section 17.04.020 (B)(6) of this Code.
   "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 (100) year frequency flood event. Application of the base flood elevation (BFE) at any location is as defined in Section 15.68.040 of this chapter.
   "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.
   "Channel" means any river, stream, creek, brook, branch, natural or artificial depression, ponded areas, flowage, slough, ditch, conduit, culvert, gully, ravine, wash, or natural or man-made drainageway, which has a definite bed and banks or shoreline, in or into which surface or groundwater flows, either perennially or intermittently.
   "Channel modification" means 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, as well as 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 typically involving relocation of the existing channel (e.g., straightening).
   "Compensatory storage" means an artificially excavated, hydraulically equivalent volume of storage within the Special Flood Hazard Area used to balance the loss of natural flood storage capacity when artificial fill or structures are placed within the floodplain.
   "Conditional approval of a regulatory floodway map change" means preconstruction approval by the Illinois Department of Natural Resources, Office of Water Resources and the Federal Emergency Management Agency 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.
   "Conditional Letter of Map Revision (CLOMR)" means 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" means a structure designed to control the rate of flow that passes through the structure, given a specific upstream and downstream water surface elevation.
   "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.
   “Detention facility”  means a facility that provides for storage of stormwater runoff and controlled release of this runoff during and after a flood or storm.
   "Development" means any engineered 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 or preparing a site for a manufactured home;
      3.   Drilling, mining, installing utilities, construction of roads, bridges, or similar projects;
      4.   Demolition of a structure or redevelopment of a site;
      5.   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; deposits of solid or liquid waste;
      6.   Any other human activity 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 re-roofing or re-surfacing 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.
   "Director" or "Director of Engineering” means the Director of Engineering of the Village. The Director performs the duties of Village Engineer pursuant to Section 2.64.010(D) of this Winnetka Village Code.
   "Elevation Certificate" means a form published by the Federal Emergency Management Agency that is used to certify the elevation to which a building has been elevated.
   "Erosion" means the general process where soils are moved by flowing water or wave action.
   "Exempt organizations" means organizations which are exempt from the operation of this chapter pursuant to state law including state, federal or local units of government.
   "FEMA" means Federal Emergency Management Agency and its regulations at 44 C.F.R. 59-79, effective as of October 1, 2000. This incorporation does not include any later editions or amendments.
   "Flood" means 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" means 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" means that portion of the floodplain outside of the regulatory floodway.
   "Flood Insurance Rate Maps (FIRM)" means a map prepared by the Federal Emergency Management Agency that depicts the Special Flood Hazard Area within a community. This map includes insurance rate zones and floodplains and may or may not depict floodways.
   "Floodplain" means 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, and the like. The floodplain is also known as the Special Flood Hazard Area (SFHA).
      1.   "Floodplains" are those lands within the jurisdiction of the Village of Winnetka that are subject to inundation by the base flood or 100-year frequency flood. The SFHA's of the Village are generally identified as such on Map Number 17031C, Panels 0113J, 0232J, 0234J, 0251J, 0253J, and 0255J, dated August 19, 2008, of the countywide Flood Insurance Rate Map for Cook County, Illinois prepared by the Federal Emergency Management Agency.
      2.   The SFHA's for those parts of unincorporated Cook County that are within the 1½ mile extraterritorial jurisdiction of the Village of Winnetka and that may be annexed into the Village are designated for the Skokie River on Map Number 17031C, Panels 0113J, 0232J, 0234J, 0251J, 0253J, and 0255J, dated August 19, 2008, of the countywide Flood Insurance Rate Map for Cook County, Illinois, prepared by the Federal Emergency Management Agency.
   "Floodproofing" means 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" means a form published by FEMA that is used to certify that a building has been designed and constructed to be structurally dry floodproofed to the flood protection elevation.
   "Flood protection elevation (FPE)" means the elevation of the base flood or one hundred (100) year frequency flood plus two feet of freeboard at any given location in the Special Flood Hazard Area.
   "Freeboard" means an increment of elevation added to the based flood elevation to provide a factor of safety of uncertainties in calculations, unknown localized conditions, wave actions and unpredictable effects such as those caused by ice or debris jams.
   "Hydrologic and hydraulic calculations" means engineering analysis which determine expected flood flows and flood elevations based on land characteristics and rainfall events.
   "IDNR/OWR"  means the Illinois Department of Natural Resources/Office of Water Resources.
   "Letter of Map Amendment (LOMA)" means official determination by FEMA that a specific structure is not in a one hundred (100) year flood zone; amends the effective Flood Hazard Boundary Map or FIRM.
   "Letter of Map Revisions (LOMR)" means letter from FEMA that revises base flood or one hundred (100) year frequency flood elevations, flood insurance rate zones, flood boundaries or floodways as shown on an effective FBFM or FIRM.
   "Minimum Average Lot Grade" is the number arrived at by applying the following formula: (FPE-2') – [(Total Required Side Yard-12') x 0.0833].
   "Mitigation" means and 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.
   "NAVD" means North American Vertical Datum of 1988; reference surface set by the National Geodetic Survey is the vertical control datum based upon the General Adjustment of the North American Datum of 1988, established in 1991 by the minimum-constraint adjustment of geodetic leveling observation in Canada, the United States, and Mexico.
   "Natural," when used in reference to channels, means those channels formed by the existing surface topography of the Earth prior to engineered changes. 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 soiled 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 re-established. Similarly, a modified channel may be restored to more natural conditions through regrading and revegetation.
   "New construction"  means structures for which the start of construction commenced on or after the effective date of a floodplain management regulation adopted by the Village and includes any subsequent improvements to such structures.
   "Ordinary high water mark (OHWM)" means 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" 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.
   "Publicly navigable waters" means all streams and lakes capable of being navigated by watercraft.
   "Registered land surveyor" means a land surveyor registered in the state of Illinois, under the Illinois Professional Land Surveyors Act of 1989, 225 ILCS 330/1 through 330/49.
   "Registered professional engineer" means an engineer registered in the state of Illinois, under the Illinois Professional Engineering Practice Act of 1989, 225 ILCS 325/1 through 325-49.
   "Regulatory floodway" means 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 one hundred (100) year frequency flood discharge with no more than a one-tenth (0.1) foot increase in stage due to the loss of flood conveyance or storage, and no more than a ten (10) percent increase in velocities.
      1.   The floodways are designated for the Skokie River on Map Number 17031C, Panels 0013J, 0232J, 0234J, 0251J, 0253J, and 0255J, dated August 19, 2008, of the countywide Flood Insurance Rate Map for Cook County, Illinois, prepared by the Federal Emergency Management Agency.
      2.   The floodways for those parts of unincorporated Cook County that are within the 1½ mile extraterritorial jurisdiction of the Village of Winnetka and that may be annexed into the Village are designated for the Skokie River on Map Number 17031C, Panels 0013G, 0232G, 0234G, 0251G, 0253G, and 0255G, dated August 19, 2008, of the countywide Flood Insurance Rate Map for Cook County, Illinois, prepared by the Federal Emergency Management Agency.
      3.   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, to both maps. Where interpretation is needed to determine the exact location of the designated floodway boundary, IDNR/OWR should be contacted for interpretation.
   "Repair, remodeling or maintenance" means development activities that do not result in any increases in the outside dimensions of a building or any changes to the dimensions of a structure.
   "Retention facility"  means a facility that stores stormwater runoff without a gravity release.
   "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.
   "Runoff" means 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" means 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)" means 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 Boundary and Floodway Map, Flood Hazard Boundary Map or Flood Insurance Rate Map as Zone A, AO, A1-30, AE, A99, AH, VO, V30, VE, V, M, E or X.
   "Structure" means the results of a human change to the land construction on or below the ground, including the construction, reconstruction or placement of a building or any addition to a building, the installation of a manufactured home on a site or the preparation of a site for a manufactured home.
   "Substantial improvement" means any repair, reconstruction or improvement of a structure, the cost, as substantiated by an executed contract that outlines the entire scope of work, of which equals or exceeds, individually or in the aggregate, fifty (50) percent of the market value of the structure either (1) before the improvement or repair is started; or (2) 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 the alteration affects the external dimensions of the structure. The term does not, however, include either any improvement necessary to make a structure comply with existing state or local health, sanitary, or safety code specifications which are solely necessary to assure safe living conditions, or any alteration of a structure listed on the National Register of Historic Places or a State Inventory of Historic Places.
   "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.
   "Village Engineer" means a registered professional engineer appointed by the Village Manager.
   "WMO" or "Watershed Management Ordinance" means the Metropolitan Water Reclamation District of Greater Chicago Countywide Watershed Management Ordinance, October 2013, as amended, and as adopted by reference in Section 15.08.040(J) of this code. (Prior code § 28.02)
(MC-5-2020, § 31, Amended 11/17/2020; MC-7-2019, Amended, 08/20/2019; MC-5-2018, Amended, 08/07/2018, reflects new FEMA maps and new formula for Minimum Average Lot Grade; MC-5-2014 §§ 13-15, 04/17/2014; MC-2-2008, Amended, 05/06/2008; MC-4-2006, Amended, 07/18/2006, Added definitions: Average Lot Grade and Minimum Average Lot Grade; MC-5-2001, Amended, 08/21/2001; MC-3-2000, Amended, 09/05/2000, IDNR/OWR replaces DWR, Regulatory Floodway redefined, reflects new FEMA maps)