A.   Short Title: This chapter of the development control ordinance shall be known and may be cited as the WESTERN SPRINGS FLOODPLAIN AND STORMWATER MANAGEMENT CHAPTER.

   B.   Authorization: The legislature of the State in the compiled statutes has delegated to local government units the authority to adopt regulations designed to control drainage, granted by 65 Illinois Compiled Statutes 5/1-2-1, 5/11-12-5, 5/11-12-6, 5/11-12-12, 5/11-13-1, 5/11-30-2, 5/11-30-8, 5/11-31-2, 5/11-109-1, 5/11-110-1, 5/11-110-2 and 50 Illinois Compiled Statutes 815/1.

   C.   Findings Of Fact:

      1.   The flood hazard areas of the Village are subject to periodic inundation which may result in loss of life and property, health and safety hazards, disruption of commerce and governmental services, extraordinary public expenditures or flood protection and relief, and impairment of the tax base, all of which adversely affect the public health, safety and general welfare.

      2.   These flood losses are caused by the cumulative effect of obstructions on areas of special flood hazards which increase flood heights and velocities and, when inadequately floodproofed, elevated or otherwise protected from flood damage also contributes to the flood loss.

   D.   Purpose: The purpose of this chapter is to maintain this Village's eligibility in the National Flood Insurance Program; to minimize potential losses due to periodic flooding including loss of life, loss of property, health and safety hazards, disruption of commerce and governmental services, extraordinary public expenditures for flood protection and relief, and impairment of the tax base, all of which adversely affect the public health, safety and general welfare; and to preserve and enhance the quality of surface waters, conserve economic and natural values and provide for the wise utilization of water and related land resources. This chapter is adopted in order to accomplish the following specific purposes:

      1.   To meet the requirements of 615 Illinois Compiled Statutes 5/18g, "an Act in relation to the regulation of the rivers, lakes and streams of the State of Illinois", approved June 10, 1911, as amended;

      2.   To assure that new development does not increase the flood or drainage hazards to others, or create unstable conditions susceptible to erosion;

      3.   To protect new buildings and major improvements to buildings from flood damage;

      4.   To protect human life and health from the hazards of flooding;

      5.   To lessen the burden on the taxpayer for flood control projects, repairs to flood damaged public facilities and utilities, and flood rescue and relief operations;

      6.   To make Federally subsidized flood insurance available for property in the Village by fulfilling the requirements of the National Flood Insurance Program;

      7.   To comply with the rules and regulations of the National Flood Insurance Program codified as 44 CFR 59-78, as amended;

      8.   To protect, conserve, and promote the orderly development of land and water resources;

      9.   To preserve the natural characteristics and functions of watercourses and floodplains in order to moderate flood and stormwater impacts, improve water quality, reduce soil erosion, protect aquatic and riparian habitat, provide recreational opportunities, provide aesthetic benefits and enhance community and economic development;

      10.   To preserve the natural characteristics of stream corridors in order to moderate flood and stormwater impacts, improve water quality, reduce soil erosion, protect aquatic and riparian habitat, provide recreational opportunities, provide aesthetic benefits and enhance community and economic development;

      11.   To diminish threats to public health, safety and welfare caused by the inundation of valuable properties by stormwater runoff, the pollution of valuable stream and lake resources by poor stormwater runoff quality and the destruction of valuable resources including aquatic habitat by excessive quantities and rates of stormwater runoff. The cause of increases in stormwater runoff quantity, rate and quality is the development and improvement of land and as such this chapter regulates these activities to prevent adverse impacts resulting from their occurrence.

   E.   Methods Of Reducing Flood Losses: In order to accomplish its purposes, this chapter includes methods and provisions for:

      1.   Restricting or prohibiting uses which are dangerous to health, safety and property due to water or erosion hazards, or which result in damaging increases in erosion or in flood heights or velocities;

      2.   Requiring that uses vulnerable to floods, including facilities which serve such uses, be protected against flood damage at the time of initial construction;

      3.   Controlling the alteration of natural floodplains, stream channels and natural or manmade protective and designated barriers, which help accommodate or channel floodwaters;

      4.   Controlling filling, grading, dredging and other development which may increase flood damage;

      5.   Preventing or regulating the construction of flood barriers which will divert floodwaters or which may increase flood hazards in other areas; and

      6.   Controlling development to assure that new development does not increase the flood or drainage hazards to others, or create unstable conditions susceptible to erosion. (Ord. 17-2866, 1-23-2017)

   A.   Scope Of Provisions:

      1.   This chapter supplements the following ordinances of the Village:

Western Springs subdivision control ordinance

Western Springs zoning ordinance

Western Springs building regulations

      2.   The provisions of this chapter regulate and restrict:

         a.   The subdivision, layout and improvement of land, including drainage, underground utilities and service facilities;

         b.   The excavating, filling and grading of lots and other parcels and areas of floodplains, the storing of certain materials thereon, modifications of streams and other floodwater runoff channels, detention ponds and basins; and

         c.   The location, construction and elevation of buildings and other structures and parts and appurtenances thereof, and the drainage of parking and other paved lots or areas.

   B.   Permits: A Village building permit and/or a development permit shall be obtained before starting any of the work regulated by this chapter. The application for such permit shall comply with the requirements of the regulations set forth in subsection A1 of this section and shall, without limitation, conform to such provisions with respect to submission and approval of preliminary and final subdivision plats, improvement plans providing for inspection, and applications for appeals; and further, such application shall be in accordance with all requirements set forth in this chapter and as required by other ordinances of the Village and the County of Cook, Statutes of the State and regulations of the National Flood Insurance Program.

   C.   Watershed Management Ordinance: The watershed management ordinance ("WMO"), adopted by the Board of Commissioners of the Metropolitan Water Reclamation District of Greater Chicago on October 3, 2013 as ordinance O13-002, as amended, is hereby adopted by reference and made applicable to "developments" and "qualified sewer construction", as defined in, and in accordance with, the terms of the watershed management ordinance, which, together with the additions, insertions, deletions and changes hereinafter set forth, three (3) copies of which have been on file for a period of more than thirty (30) days prior to the effective date hereof, are now on file in the Office of the Village Clerk.

Section 202.3 of the WMO allows the Village to impose more stringent regulations than the WMO on "developments" and "qualified sewer construction" subject to the WMO. The Village hereby exercises its authority under section 202.3 of the WMO to impose a more stringent regulation on the allowable release rate for developments in section 504.3(A) by decreasing the allowable release rate from 0.30 cfs/acre of development therein to 0.15 cfs/acre of development. Also, where there is a discrepancy or conflict between this Code and the WMO, the more stringent regulation shall govern. (Ord. 17-2866, 1-23-2017)

Unless specifically defined below, words or phrases used in this chapter shall be interpreted so as to give them the meanings they have in common usage and to give this chapter its most reasonable application:

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., as amended.

ADVERSE IMPACTS: Any deleterious impact on water resources or wetlands affecting their beneficial uses including recreation, aesthetics, aquatic habitat, quality, and quantity.

APPEAL: A request for a review of the Department of Code Enforcement and/or the Village Engineer's interpretation of any provision of this chapter or a request for a variance.

APPLICANT: Any person, firm, corporation, or governmental agency who executes the necessary forms to procure official approval of a project or permit to carry out construction of a project from the Village of Western Springs.

APPROPRIATE USE: Only uses of the designated floodway that are permissible and will be considered for permit issuance. The only uses that will be allowed are as specified in subsection 10-11-9D of this chapter.

AREA OF SPECIAL FLOOD HAZARD: The land in the floodplain within a community subject to a one percent (1%) or greater chance of flooding in any given year (100-year flood).

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.

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. 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 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 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 a 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 the Federal Emergency Management Agency of a proposed change to the floodway map. This preconstruction approval, pursuant to this definition, 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.

CONDUIT: Any channel, pipe, sewer or culvert used for the conveyance or movement of water, whether open or closed.

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 related 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 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 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.

   A.   The floodways are designated for Flagg Creek on the Countywide flood insurance rate map number 17031C and panels 0458F, 0459F, 0466F and 0467F 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 Village that may be annexed into the Village are designated for Flagg Creek on the Countywide FIRM 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.

DETENTION BASIN: A facility constructed or modified to provide for the temporary storage of stormwater runoff and the controlled release of this runoff at a prescribed rate during and after a flood or storm.

DETENTION TIME: The mean residence time of stormwater in a detention basin.

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 magnitude, frequency, direction, height, or velocity of flood or surface stormwater from properties, 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.

DRAINAGE PLAN: A plan, including engineering drawings and supporting calculations, which describes the existing stormwater drainage system and environmental features as well as the drainage system and environmental features which will be in place after development of a property.

DRY BASIN: A detention basin designed to drain completely after temporary storage of stormwater flows and to normally be dry over the majority of its bottom area.

ELEVATION CERTIFICATE: A form published by FEMA that is used to certify the BFE and the lowest elevation of a building's lowest floor.

EROSION: The general process whereby soils are moved by flowing water, wave action, wind or gravity.

EXEMPT ORGANIZATIONS: Organizations which are exempt from this chapter per the 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 designated floodway.

FLOOD INSURANCE RATE MAP (FIRM): The current version of 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): The current version of the official report in which FEMA has provided flood profile, as well as the flood boundary/floodway map and the water surface elevation of the base flood including its associated FIRMs.

FLOOD PROTECTION ELEVATION (FPE): The elevation of the base flood or 100-year frequency flood plus one foot (1') 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 Village that are subject to inundation by the base flood or 100-year frequency flood. The SFHAs of the Village are generally identified in the Cook County Countywide FIRM map panels 0458J, 0459J, 0466J, 0467J, 0468J and 0469J dated effective August 19, 2008, of the Countywide flood insurance rate map for Cook County prepared by FEMA.

   B.   The SFHAs for those parts of unincorporated Cook County that are within the one and one-half (11/2) mile extraterritorial jurisdiction of the Village and may be annexed into the Village are designated for Flagg Creek in the Cook County Countywide FIRM map panels 0458J, 0459J, 0466J, 0467J, 0468J and 0469J dated effective August 19, 2008 prepared by FEMA.

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: The channel and portion of the floodplain adjacent to a stream or watercourse that is needed to convey the base flood without cumulatively increasing the water surface elevation more than a tenth of a foot.

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.

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.

HYDROGRAPH: A graph showing, for a given location on a stream or conduit, the flow rate with respect to time.

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.

INFILTRATION: The passage or movement of water into the soil surfaces.

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, BFE, flood insurance rate zones, flood boundaries or floodways as shown on an effective FHBM or 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.

MAJOR DRAINAGE SYSTEM: That portion of a drainage system needed to store and convey flows beyond the capacity of the minor drainage system.

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 homes 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.

MINOR DRAINAGE SYSTEM: That portion of a drainage system designed for the convenience of the public. It consists of street gutters, storm sewers, small open channels, and swales and is usually designed to handle the 10-year runoff event or less.

MITIGATION: Those measures necessary to minimize the negative effects which stormwater drainage or floodplain development activities might have on the public health, safety and welfare. Any measures either singly or in combination which are designed to lessen or remedy the impacts of any activity. Examples of mitigation include compensatory storage, soil erosion and sedimentation control, and channel restoration.

NAVD 88: National American Vertical Datum of 1988. NAVD 88 supersedes the National Geodetic Vertical Datum of 1929 (NGVD).

NFIP: National Flood Insurance Program, created by Congress in 1968, administered by the Federal Insurance Administration within FEMA.

NGVD: National Geodetic Vertical Datum of 1988. 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.

NEW CONSTRUCTION: Buildings for which the start of construction was on or after the effective date of a floodplain management regulation adopted by the community, and includes subsequent improvements to such buildings.

100-YEAR EVENT: A runoff, rainfall, or flood event having a one percent (1%) chance of occurring in any given year.

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 hydrophylic vegetation or other easily recognized characteristics.

PEAK FLOW: The maximum rate of flow of water at a given point in a channel or conduit.

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 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.

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; 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 preapproved projects which are considered minor projects that are permissible per IDNR/OWR part 3708 rules for northeastern Illinois regulatory 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.

REPAIR OR REMODELING: 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 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 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 exceeding the infiltration capacity of the soil and 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): 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 insurance rate map as Zone A, AO, A1-30, AE, A99, AH, VO, V1-30, VE, V, M, or E.

START OF CONSTRUCTION: The date the building permit was issued provided the actual start of construction, repair, reconstruction, 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 manufactured home on a foundation. Permanent construction does not include land preparation, such as clearing, grading and/or walkways; nor does it include excavation for a basement, footings, piers, or foundations or the erection of temporary forms; nor does it include the installation on the property of accessory buildings such as garages or sheds not occupied as dwelling units or not part of the main structure.

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.

STORM SEWER: A closed conduit for conveying only collected stormwater.

STORMWATER DRAINAGE SYSTEM: All means, natural or manmade, used for conducting stormwater to, through or from a drainage area to the point of final outlet from a property. The stormwater drainage system includes, but is not limited to, any of the following: conduits and appurtenance features, canals, channels, ditches, streams, culverts, streets, storm sewers, detention basins, swales and pumping stations.

STORMWATER RUNOFF: The waters derived from melting snow or rain falling within a tributary drainage basin which are in excess of the infiltration capacity of the soils of that basin, which flow over the surface of the ground or are collected in channels or conduits.

STRUCTURE: See definition of building.

SUBSTANTIAL DAMAGE: Damage of any origin sustained by a structure whereby the cumulative percentage of damage during a ten (10) year period equals or exceeds fifty percent (50%) of the market value of the structure before the damage occurred regardless of actual repair work performed. Volunteer labor and materials must be included in this determination. The term includes repetitive loss buildings (see definition of repetitive loss).

SUBSTANTIAL IMPROVEMENT: Any reconstruction, rehabilitation, addition, or improvement of a structure taking place subsequent to the adoption hereof in which the cumulative percentage of improvements equals or exceeds fifty percent (50%) of the market value of the structure during a ten (10) year period before the improvement or repair is started.

TIME OF CONCENTRATION: The elapsed time for stormwater to flow from the most hydraulically remote point in a drainage basin to a particular point of interest in that watershed.

TRANSITION SECTION: Reaches of the stream or floodway where water flows from a narrow cross section to a wide cross section or vice versa.

TRIBUTARY AREA: All of the land surface area that contributes runoff to a given point.

VARIANCE: A grant of relief from the requirements of this chapter which permits construction in a manner that would otherwise be prohibited by this chapter.

VILLAGE: Village of Western Springs, Cook County, Illinois.

VILLAGE ENGINEER: The officially appointed Village Engineer of the Village or his duly authorized representative.

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.

WET BASIN: A detention basin designed to maintain a permanent pool of water after the temporary storage of stormwater runoff. (Ord. 17-2866, 1-23-2017)

The Village Engineer shall be responsible for fulfilling all of the duties listed in section 10-11-5 of this chapter.

   A.   To fulfill those duties, the Village Engineer should first use the criteria listed in section 10-11-6 of this chapter to determine whether the development site is located within a floodplain. Once it has been determined that a site is located within a floodplain, the Village Engineer must determine whether the development site is within a flood fringe, a designated floodway, or within an SFHA or floodplain for which no floodway has been identified. If the site is within a flood fringe, the Village Engineer shall require that the minimum requirements of section 10-11-7 of this chapter be met. If the site is within a floodway, the Village Engineer shall require that the minimum requirements of section 10-11-9 of this chapter be met. If the site is located within an SFHA or floodplain for which no detailed study has been completed and approved, the Village Engineer shall require that the minimum requirements of section 10-11-10 of this chapter be met. In addition, the general requirements of section 10-11-11 of this chapter shall be met for all developments meeting the requirements of section 10-11-7, 10-11-9, or 10-11-10 of this chapter.

   B.   The Village Engineer shall assure that all subdivision proposals shall meet the requirements of section 10-11-13 of this chapter.

   C.   If a variance is to be granted for a proposal, the Village Engineer shall review the requirements of section 10-11-14 of this chapter to make sure they are met. In addition, the Village Engineer shall complete all notification requirements.

   D.   In order to assure that property owners obtain permits as required in this chapter, the Village Engineer may take any and all actions as outlined in section 10-11-16 of this chapter. (Ord. 17-2866, 1-23-2017)

The Village Engineer shall be responsible for the general administration and enforcement of this chapter, including, but not limited to, the following duties:

   A.   Determining The Floodplain Designation: Check all new development sites to determine whether they are in a special flood hazard area (SFHA). If they are in an SFHA, determine whether they are in a floodway, flood fringe or in a floodplain for which a detailed study has not been conducted and which drains more than one square mile. Check whether the development is potentially within an extended SFHA (with a drainage area less than 1 square mile), indicating that the development would have adverse impacts regarding storage, conveyance, or inundation which would be the basis for the applicant being required to delineate the floodplain and floodway and be subject to the remaining sections of this chapter.

   B.   Professional Engineer Review: If the development site is within a floodway or in a floodplain for which a detailed study has not been conducted and which drains more than one square mile, the permit shall be referred to a licensed professional engineer under the employ or contract of the Village for review to ensure that the development meets the requirements of section 10-11-9 or 10-11-10 of this chapter. In the case of an appropriate use, the PE shall state in writing that the development meets the requirements of section 10-11-9 of this chapter.

   C.   Dam Safety Requirements: Dams are classified as to their size and their hazard/damage potential in the event of failure. The construction or major modification of all Class I (high hazard) and Class II (moderate hazard) dams require an IDNR/OWR dam safety permit. Some Class III (low hazard) dams require an IDNR/OWR dam safety permit, depending on the drainage area to the dam, the height of the dam and the impounding capacity behind the dam. Most off channel detention basins that have an embankment are nonjurisdictional Class III dams. It is not required that IDNR/OWR "sign off" on all nonjurisdictional Class III dams. A consulting engineer with dam safety knowledge can estimate a hazard classification and determine if an IDNR/OWR dam safety permit is required. A permit application submittal must be made to IDNR/OWR for the construction or major modification of jurisdictional dams. Regulated dams may include weirs, restrictive culverts or impoundment structures.

   D.   Other Permit Requirements: Ensure that any and all required Federal, State and local permits are received prior to the issuance of a floodplain development permit.

   E.   Plan Review And Permit Issuance: Ensure that all development activities within the SFHAs of the jurisdiction of the Village meet the requirements of this chapter and issue a floodplain development permit in accordance with the provisions of this chapter and other regulations of this community when the development meets the conditions of this chapter.

   F.   Inspection Review: Inspect all development projects before, during and after construction to assure proper elevation of the structure and to ensure compliance with the provisions of this chapter and schedule on an annual basis an inspection of the floodplain and document the results of the inspection.

   G.   Damage Determinations: Make damage determinations of all damaged buildings in the SFHA after a flood to determine substantially damaged structures, which must comply with section 10-11-3 of this chapter.

   H.   Elevation And Floodproofing Certificates: Maintain in the permit files an elevation certificate certifying the elevation of the lowest floor (including basement) of a residential or nonresidential building subject to section 10-11-12 of this chapter, or the elevation to which a nonresidential building has been floodproofed, using a floodproofing certificate, for all buildings subject to section 10-11-12 of this chapter.

   I.   Records For Public Inspection: Maintain for public inspection and furnish upon request base flood data, SFHA and designated floodway maps, copies of Federal or State permit documents, variance documentation, conditional letter of map revision, letter of map revision, letter of map amendment and "as built" elevation and floodproofing and/or elevation certificates for all buildings constructed subject to this chapter.

   J.   State Permits: Ensure that construction authorization has been granted by IDNR/OWR for all development projects subject to sections 10-11-9 and 10-11-10 of this chapter, unless enforcement responsibility has been delegated to the Village. Upon acceptance of this chapter by IDNR/OWR and FEMA, responsibility is hereby delegated to the Village as per 92 Illinois Administrative Code 708 or as otherwise recodified for construction in the designated floodway and floodplain when floodways have not been defined in sections 10-11-9 and 10-11-10 of this chapter. However, the following review approvals are not delegated to the Village and shall require review or permits from IDNR/OWR:

      1.   Organizations which are exempt from this chapter, as per the Illinois Compiled Statutes;

      2.   Department of Transportation projects, dams or impoundment structures as defined in section 10-11-3 of this chapter and all other State, Federal or local unit of government projects, including projects of the Village and County, except for those projects meeting the requirements of subsection 10-11-9I of this chapter;

      3.   An engineer's determination that an existing bridge or culvert crossing is not a source of flood damage and the analysis indicating the proposed flood profile, per subsection 10-11-9E3 of this chapter;

      4.   An engineer's analysis of the flood profile due to subsection 10-11-9E4 of this chapter;

      5.   Alternative transition sections and hydraulically equivalent compensatory storage as indicated in subsections 10-11-9E1, E2, and E8 of this chapter;

      6.   Permit issuance of structures within or over publicly navigable rivers, lakes and streams;

      7.   Any changes in the base flood elevation or floodway locations; and

      8.   Base flood elevation determinations where none now exist.

   K.   Cooperation With Other Agencies: Cooperate with State and Federal floodplain management agencies to improve base flood or 100-year frequency flood and floodway data and to improve the administration of this chapter. Submit data to IDNR/OWR and the Federal Emergency Management Agency for proposed revisions of a regulatory map. Submit reports as required for the National Flood Insurance Program. Notify the Federal Emergency Management Agency of any proposed amendments to this chapter.

   L.   Promulgate Regulations: Promulgate rules and regulations as necessary to administer and enforce the provisions of this chapter, subject however to the review and approval of IDNR/OWR and FEMA for any chapter changes. (Ord. 17-2866, 1-23-2017)

This chapter's protection standard is based on the flood insurance study for the Village. If a base flood elevation or 100-year frequency flood elevation is not available for a particular site, then the protection standard shall be according to the best existing data available from Federal, State or other sources. When a party disagrees with the best available data, they shall submit a detailed engineering study needed to replace existing data with better data and submit it to IDNR/OWR and FEMA for review and consideration prior to any development of the site.

   A.   The base flood or 100-year frequency flood elevation for the SFHAs of Flagg Creek shall be as delineated on the 100-year flood profiles in the applicable FIS of Cook County prepared by FEMA dated August 19, 2008, and such amendments to such study and maps as may be prepared from time to time.

   B.   The base flood or 100-year frequency flood elevation for the SFHAs of those parts of unincorporated Cook County that are within the extraterritorial jurisdiction of the Village or that may be annexed into the Village shall be as delineated on the 100-year flood profiles in the FIS of Cook County prepared by FEMA and dated August 19, 2008, and such amendments or revisions to such study and maps as may be prepared from time to time.

   C.   The base flood or 100-year frequency flood elevation for each SFHA delineated as an "AH Zone" or "AO Zone" shall be that elevation (or depth) delineated on the Countywide flood insurance rate map of Cook County.

   D.   The base flood or 100-year frequency flood elevation for each of the remaining SFHAs delineated as an "A Zone" on the Countywide flood insurance rate map of Cook County shall be according to the best existing data available from Federal, State or other sources. Should no other data exist, an engineering study must be financed by the applicant to determine base flood elevations. When no base flood or 100-year frequency flood elevation exists, the base flood or 100-year frequency flood elevation for a riverine SFHA shall be determined from a backwater model, such as HEC-II, HEC-RAS, or a dynamic model such as HIP. The flood flows used in the hydraulic models shall be obtained from a hydrologic model, such as HEC-HMS, HEC-1, TR-20, or HIP, or by techniques presented in various publications prepared by the United States Geological Survey for estimating peak flood discharges. For a nonriverine SFHA, the base flood elevation shall be the historic flood of record plus three feet (3'), unless calculated by a detailed engineering study. For an unmapped extended SFHA (with a drainage area less than 1 square mile) which has been identified by the Village Engineer pursuant to section 10-11-5 of this chapter, the base flood elevation shall be determined by the applicant utilizing a method as approved in this section. (Ord. 17-2866, 1-23-2017)

Development in and/or filling of the flood fringe will be permitted if protection is provided against the base flood or 100-year frequency flood by proper elevation, and compensatory storage and other provisions of this chapter are met. No use will be permitted which adversely affects the capacity of drainage facilities or systems. Developments located within the flood fringe shall meet the requirements of this section, along with the requirements of section 10-11-12 of this chapter.

   A.   Development Permit: No person, firm, corporation, or governmental body not exempted by State law shall commence any development in the SFHA without first obtaining a development permit from the Village.

   B.   Application For Development Permit: Application for a development permit shall be made on a form provided by the Village. The application shall be accompanied by drawings of the site, drawn to scale, showing property line dimensions and legal description for the property and sealed by a licensed engineer, architect or land surveyor; existing grade elevations in MSL, 1929 adjustment datum or NGVD and all changes in grade resulting from excavation or filling; the location and dimensions of all buildings and additions to buildings. For all proposed buildings, the elevation of the lowest floor (including basement) and lowest adjacent grade shall be shown on the submitted plans and the development will be subject to the requirements of section 10-11-12 of this chapter.

   C.   Review Of Application By Village Engineer: Upon receipt of a development permit application, the Village shall compare the elevation of the site to the base flood or 100-year frequency flood elevation. Any development located on land that can be shown to be higher than the base flood elevation of the current flood insurance rate map and which has not been filled after the date of the site's first flood insurance rate map without a permit as required by this chapter is not in the SFHA and, therefore, not subject to the requirements of this chapter. Conversely, any development located on land shown to be below the base flood elevation and hydraulically connected, but shown on the current flood insurance rate map is subject to the provisions of this chapter. The Village shall maintain documentation of the existing ground elevation at the development site and certification that this ground elevation existed prior to the date of the site's first flood insurance rate map identification. A soil erosion and sediment control plan for disturbed areas shall be submitted. This plan shall include a description of the sequence of grading activities and the temporary sediment and erosion control measures to be implemented to mitigate their effects. This plan shall also include a description of final stabilization and revegetation measures, and the identification of a responsible party to ensure postconstruction maintenance. The Village shall be responsible for obtaining from the applicant copies of all other Federal, State, and local permits, approvals or waivers that may be required for this type of activity. The Village shall not issue a permit unless all other Federal, State, and local permits have been obtained.

   D.   Soil Erosion And Sedimentation Control Plan: A soil erosion and sedimentation control plan for disturbed areas shall be submitted. This plan shall include a description of the sequence of grading activities and the temporary sediment and erosion control measures to be implemented to mitigate their effects. This plan shall also include a description of final stabilization and revegetation measures, and the identification of a responsible party to ensure postconstruction maintenance.

   E.   Copies Of Other Required Permits: The Department of Code Enforcement shall be responsible for obtaining from the applicant, copies of all other local, State and Federal permits, approvals or permit-not-required letters that may be required for this type of activity. The Village shall not issue a permit unless all other local, State and Federal permits have been obtained.

   F.   Preventing Increased Damages: No development in the flood fringe shall create a threat to public health and safety.

   G.   Elevation Of Site: If fill is being used to elevate the site above the base flood or 100-year frequency flood elevation, the applicant shall submit sufficient data and obtain a letter of map revision (LOMR) from FEMA for the purpose of removing the site from the floodplain.

   H.   Compensatory Storage: Whenever any portion of a floodplain is authorized for use, the volume of space which will be occupied by the authorized fill or structure below the base flood or 100-year frequency flood elevation shall be compensated for and balanced by a hydraulically equivalent volume of excavation taken from below the base flood or 100-year frequency flood elevation. The excavation volume shall be at least equal to 1.5 times the volume of storage lost due to the fill or structure. In the case of streams and watercourses, such excavation shall be made opposite or adjacent to the areas so filled or occupied. All floodplain storage lost below the existing 10-year flood elevation shall be replaced below the proposed 10-year flood elevation. All floodplain storage lost above the existing 10-year flood elevation shall be replaced above the proposed 10-year flood elevation. All such excavations shall be constructed to drain freely and openly to the watercourse. (Ord. 17-2866, 1-23-2017)

A person who has obtained a letter of map revision based on fill that removes a site in the flood fringe from the floodplain due to the use of fill to elevate the site above the BFE, may apply for a permit from the Village to construct the lowest floor of a residential building below the BFE in the flood fringe. The Village shall not issue such a permit unless the applicant has complied with all the criteria set forth in the following subsections:

   A.   Compensatory storage shall be provided per subsection 10-11-7H of this chapter.

   B.   The elevation of the lowest opening in the basement wall (i.e., window wells, accessways) shall be at or above the flood protection elevation (FPE).

   C.   The lowest adjacent grade to the foundation shall be at or above the FPE, for a minimum distance of ten feet (10') beyond the outside face of the structure. However, if site conditions are such that this requirement cannot be met, the Village may waive the ten foot (10') minimum setback if an Illinois licensed professional engineer certifies that an alternative method to protect the building from damage due to hydrostatic pressures has been met. The certifications shall be in the form of a detailed soils and structural design analysis, which shall be submitted to the Village for review. The Village may require such additional documentation as necessary to prove that the proposed shorter setback distance will keep the structure reasonably safe. In no case shall the setback distance be less than four feet (4').

   D.   In the case of new construction that includes a basement complying with the requirements of a simplified approach of seepage flow analysis under FEMA Technical Bulletin 10-01, the grade around the perimeter of the structure, measured at a distance of twenty feet (20') from the structure, shall be above the BFE. However, if site conditions are such that this requirement cannot be obtained, the Village may waive the twenty foot (20') minimum setback distance if an Illinois licensed professional engineer certifies that an alternative method to protect the building from damages due to hydrostatic pressures has been met using the engineered basement option of Technical Bulletin 10-01. A detailed soils analysis and structural design proving that a shorter setback distance will keep the structure reasonably safe from flooding shall be submitted to the Village for review. In no case shall the setback distance be less than four feet (4').

   E.   The ground around the building shall be compacted fill that meets all requirements of this section and is at least five feet (5') thick under the basement floor slab. Nothing in this section shall be interpreted to require the removal or replacement of fill that was placed as part of an LOMR-F, if such fill consists of material, including soils of similar classification and degree permeability, such as those classified as CH, CL, SC or ML according to ASTM standard D-2487, classification of soils for engineering purposes.

   F.   The fill material must be homogeneous and isotropic; that is, the soil must be all of one material, and the engineering properties must be the same in all the directions.

   G.   All fill material and compaction shall be designed, certified and inspected by an Illinois licensed professional engineer, as warranted by the site conditions.

   H.   The basement floor shall be at an elevation that is no more than five feet (5') below the BFE.

   I.   There shall be a granular drainage layer beneath the floor slab, and minimum of one-fourth (1/4) horsepower sump pump with a backup power supply shall be provided to remove seepage flow. The pump shall be rated at four (4) times the estimated seepage rate and shall discharge above the BFE and away from the building in order to prevent flooding of the basement or uplift of the floor under the effect of the seepage pressure.

   J.   The drainage system shall be equipped with a positive means of preventing backflow.

   K.   All foundation elements shall be designed to withstand hydrostatic pressure in accordance with accepted engineering practices.

   L.   If the applicant is unable to meet all of the requirements set forth in the preceding subsections of this section, the Village may allow the construction of a basement below the BFE only if the applicant demonstrates that the proposed fill and structure meet the guidelines and requirements set forth in FEMA Technical Bulletin 10-01 and are reasonably safe from flooding. In order to demonstrate that the proposed structure is reasonably safe from flooding, the applicant shall submit a detailed engineering analysis of the proposed fill and foundation wall. The engineered basement study shall be completed in accordance with the latest edition of FEMA Technical Bulletin 10-01, with the analysis of the fill being prepared by an Illinois licensed professional engineer.

   M.   In order to provide the required compensatory storage on site, in no case shall the depth of excavation in the front and side yards of the lot exceed eighteen inches (18"), as measured from the previously existing natural grade. The rear yard shall be permitted to have a greater depth of excavation, if necessary. All such excavation shall be constructed to drain freely and openly to the watercourse or storm sewer system. The use of mechanical means to drain the compensatory storage area will not be permitted. (Ord. 17-2866, 1-23-2017)

This section applies to proposed development, redevelopment, site modification or building modification within a designated floodway. The designated floodway for Flagg Creek shall be as delineated on the designated floodway maps designated by IDNR/OWR according and referenced in section 10-11-3 of this chapter and by the Cook County Countywide FIRM and FIS approved August 19, 2008. Only those uses and structures will be permitted which meet the criteria in this section. All floodway modifications shall be the minimum necessary to accomplish the purpose of the project. The development shall also meet the requirements of section 10-11-12 of this chapter.

   A.   Development Permit: No person, firm, corporation or governmental body not exempted by State law shall commence any development in a floodway without first obtaining a development permit from the Village.

   B.   Application For Permit; Contents: Application for a development permit shall be made on a form provided by the Village. The application shall include the following information:

      1.   Name and address of applicant.

      2.   Site location (including legal description) of the property, drawn to scale, on the designated floodway map, indicating whether it is proposed to be in an incorporated or unincorporated area.

      3.   Name of stream or body of water affected.

      4.   Description of proposed activity.

      5.   Statement of purpose of proposed activity.

      6.   Anticipated dates of initiation and completion of activity.

      7.   Name and mailing address of the owner of the subject property if different from the applicant.

      8.   Signature of applicant or the applicant's agent.

      9.   If the applicant is a corporation, the president or other authorized officer shall sign the application form.

      10.   If the applicant is a partnership, each partner shall sign the application form.

      11.   If the applicant is a land trust, the trust officer shall sign the name of the trustee by him (her) as trust officer. A disclosure affidavit shall be filed with the application, identifying each beneficiary of the trust by name and address and defining the respective interests therein.

      12.   Plans of the proposed activity shall be provided which include as a minimum:

         a.   A vicinity map showing the site of the activity, name of the waterway, boundary lines, names of roads in the vicinity of the site, graphic or numerical scale, and north arrow;

         b.   A plan view of the project and engineering study reach showing existing and proposed conditions including principal dimensions of the structure or work, elevations in mean sea level (1929 adjustment) datum or NGVD, adjacent property lines and ownership, drainage and flood control easements, location of any channels and any existing or future access roads, distance between proposed activity and navigation channel (when the proposed construction is near a commercially navigable body of water), designated floodway limit, floodplain limit, specifications and dimensions of any proposed channel modifications, location and orientation of cross sections, north arrow, and a graphic or numerical scale;

         c.   Cross section views of the project and engineering study reach showing existing and proposed conditions including principal dimensions of the work as shown in plan view, existing and proposed elevations, normal water elevation, 10-year frequency flood elevation, 100-year frequency flood elevation, and graphic or numerical scales (horizontal and vertical);

         d.   A soil erosion and sedimentation control plan for disturbed areas. This plan shall include a description of the sequence of grading activities and the temporary sediment and erosion control measures to be implemented to mitigate their effects. This plan shall also include a description of final stabilization and revegetation measures, and the identification of a responsible party to ensure postconstruction maintenance;

         e.   A copy of the designated floodway map, marked to reflect any proposed change in the designated floodway location.

      13.   Any and all other local, State and Federal permits or approval letters that may be required for this type of development.

      14.   Engineering calculations and supporting data shall be submitted showing that the proposed work will meet the permit criteria of subsection D of this section.

      15.   If the designated floodway delineation, base flood or 100-year frequency flood elevation will change due to the proposed project, the application will not be considered complete until IDNR/OWR has indicated conditional approval of the designated floodway map change. No structures may be built until a letter of map revision has been approved by FEMA.

      16.   The application for a structure shall be accompanied by drawings of the site, drawn to scale showing property line dimensions and existing ground elevations and all changes in grade resulting from any proposed excavation or filling, and floodplain and floodway limits; sealed by a registered professional engineer, licensed architect or registered land surveyor; the location and dimensions of all buildings and additions to buildings; and the elevation of the lowest floor (including basement) of all proposed buildings subject to the requirements of section 10-11-12 of this chapter.

      17.   If the proposed project involves a channel modification, the applicant shall submit the following information:

         a.   A discussion of the purpose of and need for the proposed work;

         b.   A discussion of the feasibility of using alternative locations or methods to accomplish the purpose of the proposed work;

         c.   An analysis of the extent and permanence of the impacts the project would have on the physical and biological conditions of the body of water affected;

         d.   An analysis of the extent and permanence of the impacts each feasible alternative identified in subsection E of this section would have on the physical and biological conditions of the body of water affected;

         e.   An analysis of the impacts of the proposed project, considering cumulative effects on the physical and biological conditions of the body of water affected.

   C.   Copies Of Other Required Permits: The Department of Code Enforcement shall be responsible for obtaining from the applicant copies of all other local, State and Federal permits and approvals that may be required for this type of activity. The Village shall not issue the development permit unless all required Federal and State permits have been obtained. A registered professional engineer under the employ or contract of the Village shall review and approve applications reviewed under this section.

   D.   Preventing Increased Damages And A List Of Appropriate Uses: The only development in a floodway which will be allowed are appropriate uses, which will not cause a rise in the base flood elevation, and which will not create a damaging or potentially damaging increase in flood heights or velocity or be a threat to public health and safety and welfare or impair the natural hydrologic and hydraulic functions of the floodway or channel, or permanently impair existing water quality or aquatic habitat.

Construction impacts shall be minimized by appropriate mitigation methods as called for in this chapter. Only those appropriate uses listed in 92 Illinois Administrative Code 708 or as otherwise recodified will be allowed.

Appropriate uses do not include the construction or placement of any new structures, fill, building additions, buildings on stilts, excavation or channel modifications done to accommodate otherwise nonappropriate uses in the floodway, fencing (including landscaping or planting designed to act as a fence) and storage of materials except as specifically defined above as an appropriate use. The approved appropriate uses are as follows:

      1.   Flood control structures, dikes, dams and other public works or private improvements relating to the control of drainage, flooding, erosion, or water quality or habitat for fish and wildlife;

      2.   Structures or facilities relating to the use of, or requiring access to, the water or shoreline, such as pumping and treatment facilities, and facilities and improvements related to recreational boating, commercial shipping and other functionally water dependent uses;

      3.   Storm and sanitary sewer outfalls;

      4.   Underground and overhead utilities;

      5.   Recreational facilities such as playing fields and trail systems including any related fencing (at least 50 percent open when viewed from any 1 direction) built parallel to the direction of flood flows, and including open air pavilions;

      6.   Detached garages, storage sheds, or other nonhabitable accessory structures without toilet facilities to existing buildings that will not block flood flows, nor reduce floodway storage;

      7.   Bridges, culverts, roadways, sidewalks, railways, runways and taxiways and any modification thereto;

      8.   Parking lots and any modifications thereto (where depth of flooding at the 100-year frequency flood event will not exceed 1.0 feet) and aircraft parking aprons built at or below ground elevation;

      9.   Designated floodway regrading, without fill, to create a positive nonerosive slope toward a watercourse;

      10.   Floodproofing activities to protect previously existing lawful structures including the construction of watertight window wells, elevating structures, or construction of floodwalls around residential, commercial or industrial principal structures where the outside toe of the floodwall shall be no more than ten feet (10') away from the exterior wall of the existing structure, and, which are not considered substantial improvements to the structure;

      11.   In the case of damaged or replacement buildings, reconstruction or repairs made to a building that are valued at less than fifty percent (50%) of the market value of the building before it was damaged or replaced, and which do not increase the outside dimensions of the building;

      12.   Additions to existing buildings above the BFE that do not increase the building's footprint and are valued at less than fifty percent (50%) of the market value of the building.

   E.   Engineering And Mitigation Criteria: Appropriate uses do not include the construction or placement of any new structures, fill, building additions, buildings on stilts, excavation or channel modifications done to accommodate otherwise nonappropriate uses in the floodway, fencing (including landscaping or planting designed to act as a fence) and storage of materials except as specifically defined above as an appropriate use.

      1.   Preservation Of Flood Conveyance, So As Not To Increase Flood Stages Upstream: For appropriate uses other than bridge or culvert crossings, on stream structures or dams, all effective designated floodway conveyance lost due to the project will be replaced for all flood events up to and including the 100-year frequency flood. In calculating effective designated floodway conveyance, the following factors shall be taken into consideration:

         a.   Designated floodway conveyance,

   "K" = (1.486A*(R^2/3))/n

where "n" is Manning's roughness factor, "A" is the effective area of the cross section, and "R" is the ratio of the area to the wetted perimeter. (See "Open Channel Hydraulics" by Ven Te Chow, 1959, McGraw-Hill Book Company, New York.)

         b.   The same Manning's "n" value shall be used for both existing and proposed conditions unless a recorded maintenance agreement with a Federal, State, or local unit of government can assure the proposed conditions will be maintained or the land cover is changing from a vegetative to a nonvegetative land cover.

         c.   Transition sections shall be provided and used in calculations of effective designated floodway conveyance. The following expansion and contraction ratios shall be used unless an applicant's engineer can prove to IDNR/OWR through engineering calculations or model tests that more abrupt transitions may be used with the same efficiency:

            (1)   When water is flowing from a narrow section to a wider section, the water should be assumed to expand no faster than at a rate of one foot (1') horizontal for every four feet (4') of the flooded stream's length.

            (2)   When water is flowing from a wide section to a narrow section, the water should be assumed to contract no faster than at a rate of one foot (1') horizontal for every one foot (1') of the flooded stream's length.

            (3)   When expanding or contracting flows in a vertical direction, a minimum of one foot (1') vertical transition for every ten feet (10') of stream length shall be used.

            (4)   Transition sections shall be provided between cross sections with rapid expansions and contractions and when meeting the designated floodway delineation on adjacent properties.

            (5)   All cross sections used in the calculations shall be located perpendicular to flood flows.

      2.   Preservation Of Floodway Storage So As Not To Increase Downstream Flooding: Compensatory storage shall be provided for any designated floodway storage lost due to the proposed work from the volume of fill or structures placed and the impact of any related flood control projects. Compensatory storage for fill or structures shall be equal to at least 1.5 times the volume of floodplain storage lost. Artificially created storage lost due to a reduction in head loss behind a bridge shall not be required to be replaced. The compensatory designated floodway storage shall be placed between the proposed normal water elevation and the proposed 100-year flood elevation. All designated floodway storage lost below the existing 10-year flood elevation shall be replaced below the proposed 10-year flood elevation. All designated floodway storage lost above the existing 10-year flood elevation shall be replaced above the proposed 10-year flood elevation. All such excavations shall be constructed to drain freely and openly to the watercourse.

If the compensatory storage will not be placed at the location of the proposed construction, the applicant's engineer shall demonstrate to IDNR/OWR through a determination of flood discharges and water surface elevations that the compensatory storage is hydraulically equivalent. Finally, there shall be no reduction in floodway surface area as a result of a floodway modification, unless such modification is necessary to reduce flooding at existing structure.

      3.   Preservation Of Floodway Velocities So As Not To Increase Stream Erosion Or Flood Heights: For all appropriate uses, except bridges or culverts or on stream structures, the proposed work will not result in an increase in the average channel or designated floodway velocities or stage for all flood events up to and including the 100-year frequency event. However in the case of bridges or culverts or on stream structures built for the purpose of backing up water in the stream during normal or flood flows, velocities may be increased at the structure site if scour, erosion and sedimentation will be avoided by the use of riprap or other design measures.

      4.   Construction Of New Bridges Or Culvert Crossings And Roadway Approaches: The proposed structure shall not result in an increase of upstream flood stages greater than one-tenth of one foot (0.1') when compared to the existing conditions for all flood events up to and including the 100-year frequency event; or the upstream flood stage increases will be contained within the channel banks (or within existing vertical extensions of the channel banks) such as within the design protection grade of existing levees or floodwalls or within recorded flood easements. If the proposed construction will increase upstream flood stages greater than one-tenth of one foot (0.1'), the developer must contact IDNR/OWR, dam safety section for a dam safety permit or waiver.

         a.   The engineering analysis of upstream flood stages must be calculated using the flood study flows, and corresponding flood elevations for tailwater conditions for the flood study specified in section 10-11-6 of this chapter. Culverts must be analyzed using U.S. DOT, FHWA hydraulic chart for the selection of highway culverts. Bridges must be analyzed using the U.S. DOT/Federal Highway Administration hydraulics of bridge waterways calculation procedures.

         b.   Lost floodway storage must be compensated for per subsection E2 of this section.

         c.   Velocity increases must be mitigated per subsection E3 of this section.

         d.   If the crossing is proposed over a public water that is used for recreational or commercial navigation, a Department of Transportation permit must be received.

         e.   The hydraulic analysis for the backwater caused by the bridge showing the existing condition and proposed designated profile must be submitted to IDNR/OWR for concurrence that a CLOMR is not required by subsection E14 of this section.

         f.   All excavations for the construction of the crossing shall be designed per subsection E8 of this section.

      5.   Reconstruction Or Modification Of Existing Bridges, Culverts, And Approach Roads:

         a.   The bridge or culvert and roadway approach reconstruction or modification shall be constructed with no more than one-tenth of one foot (0.1') increase in backwater over the existing flood profile for all flood frequencies up to and including the 100-year event, if the existing structure is not a source of flood damage.

         b.   If the existing bridge or culvert or roadway approach is a source of flood damage to buildings or structures in the upstream floodplain, the applicant's engineer shall evaluate the feasibility of redesigning the structure to reduce the existing backwater, taking into consideration the effects of flood stages on upstream and downstream properties.

         c.   The determination as to whether or not the existing crossing is a source of flood damage and should be redesigned must be prepared in accordance with the Department of Transportation rules, 92 Illinois Administrative Code 708 (floodway construction in northeastern Illinois), or as otherwise recodified, and submitted to the division for review and concurrence before a permit is issued.

      6.   On Stream Structures Built For The Purpose Of Backing Up Water: Any increase in upstream flood stages greater than 0.0 feet when compared to the existing conditions, for all flood events up to and including the 100-year frequency event shall be contained within the channel banks (or within existing vertical extensions of the channel banks) such as within the design protection grade of existing levees or floodwalls or within recorded flood easements. A permit or letter indicating a permit is not required must be obtained from IDNR/OWR, dam safety section for a dam safety permit or waiver for any structure built for the purpose of backing up water in the stream during normal or flood flow. All dams and impoundment structures as defined in section 10-11-3 of this chapter shall meet the permitting requirements of 92 Illinois Administrative Code 702 (construction and maintenance of dams), or as otherwise recodified. If the proposed activity involves a modification of the channel or floodway to accommodate an impoundment, it shall be demonstrated that:

         a.   The impoundment is determined to be in the public interest by providing flood control, public recreation, or regional stormwater detention.

         b.   The impoundment will not prevent the migration of indigenous fish species, which require access to upstream areas as part of their life cycle, such as for spawning.

         c.   The impoundment will not cause or contribute to degraded water quality or habitat conditions. Impoundment design should include gradual bank slopes, appropriate bank stabilization measures, and a presedimentation basin.

         d.   A nonpoint source control plan has been implemented in the upstream watershed to control the effects of sediment runoff as well as minimize the input of nutrients, oil and grease, metals, and other pollutants.

If there is more than one municipality in the upstream watershed, the municipality in which the impoundment is constructed should coordinate with upstream municipalities to ensure comprehensive watershed control.

         e.   The project otherwise complies with the requirements of this section.

      7.   Floodproofing Of Existing Habitable, Residential And Commercial Structures: If construction is required beyond the outside dimensions of the existing building, the outside perimeter of the floodproofing construction shall be placed no farther than ten feet (10') from the outside of the building. Compensation of lost storage and conveyance will not be required for floodproofing activities.

      8.   Excavation In The Floodway: When excavation is proposed in the design of bridges and culvert openings, including the modifications to and replacement of existing bridge and culvert structures, or to compensate for lost conveyance for other appropriate uses, transition sections shall be provided for the excavation. The following expansion and contraction ratios shall be used unless an applicant's engineer can prove to IDNR/OWR through engineering calculations or model tests that more abrupt transitions may be used with the same efficiency:

         a.   When water is flowing from a narrow section to a wider section, the water should be assumed to expand no faster than at a rate of one foot (1') horizontal for every four feet (4') of the flooded stream's length;

         b.   When water is flowing from a wide section to a narrow section, the water should be assumed to contract no faster than at a rate of one foot (1') horizontal for every one foot (1') of the flooded stream's length; and

         c.   When expanding or contracting flows in a vertical direction, a minimum of one foot (1') vertical transition for every ten feet (10') of stream length shall be used.

         d.   Erosion/scour protection shall be provided inland upstream and downstream of the transition sections.

      9.   Channel Modifications; When Allowed: If the proposed activity involves a channel modification, it shall be demonstrated that:

         a.   There are no practicable alternatives to the activity which would accomplish its purpose with less impact to the natural conditions of the body of water affected. Possible alternatives include levees, bank stabilization, floodproofing of existing structures, removal of structures from the floodplain, clearing the channel, high flow channel or the establishment of a stream side buffer strip or greenbelt.

Channel modification is acceptable if the purpose is to restore natural conditions and improve water quality and fish and wildlife habitat.

         b.   Water quality, habitat, and other natural functions would be significantly improved by the modification and no significant habitat area may be destroyed, or the impacts are offset by the replacement of an equivalent degree of natural resource values.

         c.   The activity has been planned and designed and will be constructed in a way which will minimize its adverse impacts on the natural conditions of the body of water affected, consistent with the following criteria:

            (1)   The physical characteristics of the modified channel shall match as closely as possible those of the existing channel in length, cross section, slope and sinuosity. If the existing channel has been previously modified, restoration of more natural physical conditions should be incorporated into channel modification design, where practical.

            (2)   Hydraulically effective transitions shall be provided at both the upstream and downstream ends of the project, designed such that they will prevent erosion.

            (3)   One sided construction of a channel shall be used when feasible. Removal of streamside (riparian) vegetation should be limited to one side of the channel, where possible, to preserve the shading and stabilization effects of the vegetation.

            (4)   Clearing of vegetation shall be limited to that which is essential for construction of the channel.

            (5)   Channel banks shall be constructed with a side slope no steeper than three to one (3:1) horizontal to vertical, wherever practicable. Natural vegetation and gradual side slopes are the preferred methods for bank stabilization. Where high velocities or sharp bends necessitate the use of alternative stabilization measures, natural rock or riprap are preferred materials. Artificial materials such as concrete, gabions, or construction rubble should be avoided unless there are no practicable alternatives.

            (6)   All disturbed areas associated with the modification shall be seeded or otherwise stabilized as soon as possible upon completion of construction. Erosion blanket or an equivalent material shall be required to stabilize disturbed channel banks prior to establishment of the vegetative cover.

            (7)   If the existing channel contains considerable bottom diversity such as deep pools, riffles, and other similar features, such features shall be provided in the new channel. Spawning and nesting areas and flow characteristics compatible with fish habitat shall also be established, where appropriate.

            (8)   A sediment basin shall be installed at the downstream end of the modification to reduce sedimentation and degradation of downstream water quality.

            (9)   New or relocated channels should be built in the dry and all items of construction, including vegetation, should be completed prior to diversion of water into the new channel.

            (10)   There shall be no increases in stage or velocity as the channel enters or leaves the project site for any frequency flood unless necessitated by a public flood control project or unless such an increase is justified as part of a habitat improvement or erosion control project.

            (11)   Unless the modification is for a public flood control project, there shall be no reduction in the volume of floodwater storage outside the floodway as a result of the modification.

         d.   The project otherwise complies with the requirements of this section.

      10.   Seeding And Stabilization Plan: For all activities located in a floodway, a seeding and stabilization plan shall be submitted by the applicant.

      11.   Soil Erosion And Sedimentation Measures: For all activities in the floodway, including grading, filling, and excavation in which there is potential for erosion of exposed soil, soil erosion and sedimentation control measures shall be employed consistent with the following criteria:

         a.   The construction area shall be minimized to preserve the maximum vegetation possible. Construction shall be scheduled to minimize the time soil is exposed and unprotected. In no case shall the existing natural vegetation be destroyed, removed, or disturbed more than fifteen (15) days prior to the initiation of improvements.

         b.   Temporary and/or permanent soil stabilization shall be applied to denuded areas as soon as possible. As a minimum, soil stabilization shall be provided within fifteen (15) days after final grade is reached on any portion of the site, and within fifteen (15) days to denuded areas which may not be at final grade but will remain undisturbed for longer than sixty (60) days.

         c.   Sedimentation control measures shall be installed before any significant grading or filling is initiated on the site to prevent the movement of eroded sediments off site or into the channel. Potential sediment control devices include filter fences, straw bale fences, check dams, diversion ditches and sediment basins.

         d.   A vegetated buffer strip of at least twenty five feet (25') in width shall be preserved and/or reestablished, where possible, along existing channels (see subsection E9 of this section). Construction vehicle use of channels shall be minimized. Temporary stream crossings shall be constructed, where necessary, to minimize erosion. Necessary construction in or along channels shall be restabilized immediately.

         e.   Soil erosion and sedimentation control measures shall be designed and implemented consistent with "Procedures and Standards for Urban Soil Erosion and Sedimentation Control in Illinois" (1988 and as amended) also known as the "Green Book" and "Standards and Specifications for Soil Erosion and Sediment Control" (IEPA, 1987 and as amended).

      12.   Public Flood Control Projects: For public flood control projects, the permitting requirements of this section will be considered met if the applicant can demonstrate to IDNR/OWR through hydraulic and hydrologic calculations that the proposed project will not singularly or cumulatively result in increased flood heights outside the project right-of-way or easements for all flood events up to and including the 100-year frequency event.

      13.   General Criteria For Analysis Of Flood Elevations:

         a.   The flood profiles, flows and floodway data in the designated floodway study, referenced in section 10-11-6 of this chapter, must be used for analysis of the base conditions. If the study data appears to be in error or conditions have changed, IDNR/OWR shall be contacted for approval and concurrence on the appropriate base conditions data to use.

         b.   If the 100-year designated floodway elevation at the site of the proposed construction is affected by backwater from a downstream receiving stream with a larger drainage area, the proposed construction shall be shown to meet the requirements of this section for the 100-year frequency flood elevations of the designated floodway conditions and conditions with the receiving stream at normal water elevations.

         c.   If the applicant learns from IDNR/OWR, local governments, or a private owner that a downstream restrictive bridge or culvert is scheduled to be removed, reconstructed, modified, or a regional flood control project is scheduled to be built, removed, constructed or modified within the next five (5) years, the proposed construction shall be analyzed and shown to meet the requirements of this section for both the existing conditions and the expected flood profile conditions when the bridge, culvert or flood control project is built.

      14.   Conditional Letter Of Map Revision: If the appropriate use would result in a change in the designated floodway location or the 100-year frequency flood elevation, the applicant shall submit to IDNR/OWR and to FEMA all the information, calculations and documents necessary to be issued a conditional designated floodway map revision and receive from IDNR/OWR a conditional approval of the designated floodway change before a permit is issued. However, the final designated floodway map will not be changed by IDNR/OWR until as built plans or record drawings are submitted and accepted by FEMA and IDNR/OWR.

In the case of nongovernment projects, the municipality in incorporated areas and the county in unincorporated areas shall concur with the proposed conditional designated floodway map revision before IDNR/OWR approval can be given. No filling, grading, dredging or excavating shall take place until a conditional approval is issued. No further development activities shall take place until a final letter of map revision (LOMR) is issued by FEMA and IDNR/OWR.

      15.   Professional Engineer's Supervision: All engineering analyses shall be performed by or under the supervision of a registered professional engineer.

      16.   Construction Near Channel; Criteria: For all activities in the floodway involving construction within twenty five feet (25') of the channel, the following criteria shall be met:

         a.   A natural vegetation buffer strip shall be preserved within at least twenty five feet (25') of the ordinary high water mark of the channel.

         b.   Where it is impossible to protect this buffer strip during the construction of an appropriate use, a vegetated buffer strip shall be established upon completion of construction.

         c.   The use of native riparian vegetation is preferred in the buffer strip. Access through this buffer strip shall be provided, when necessary, for stream maintenance purposes.

After receipt of conditional approval of the designated floodway change and issuance of a permit and a conditional letter of map revision, construction as necessary to change the floodway designation may proceed but no buildings or structures or other construction that is not an appropriate use may be placed in that area until the designated floodway map is changed and a final letter of map revision is received. The designated floodway map will be revised upon acceptance and concurrence by IDNR/OWR and FEMA of the "as built" plans.

   F.   State Review: For those projects listed below located in a designated floodway, the following criteria shall be submitted to IDNR/OWR for their review and concurrence and/or permit prior to the issuance of a permit by a community or County delegated State permitting authority in the floodway:

      1.   IDNR/OWR will review an engineer's analysis of the flood profile due to a proposed bridge pursuant to subsection E of this section.

      2.   IDNR/OWR will review an engineer's determination that an existing bridge or culvert crossing is not a source of flood damage and the analysis indicating the proposed flood profile, pursuant to subsection E of this section.

      3.   IDNR/OWR will review alternative transition sections and hydraulically equivalent storage pursuant to subsection E of this section.

   G.   Other Permits: In addition to the other requirements of this chapter, a development permit for a site located in a floodway shall not be issued unless the applicant first obtains a permit or written documentation that a permit is not required from IDNR/OWR, issued pursuant to 615 Illinois Compiled Statutes 5/5 et seq. No permit from IDNR/OWR shall be required if the division has delegated this responsibility to the Village.

   H.   Dam Safety Permits: Any work involving the construction, modification or removal of a "dam" as defined in section 10-11-3 of this chapter per 92 Illinois Administrative Code 702 (rules for construction of dams) or as otherwise recodified shall obtain an Illinois Division of Water Resources dam safety permit prior to the start of construction of a dam. If the Village finds a dam that does not have an IDNR/OWR permit, the Village shall immediately notify the dam safety section of the Division of Water Resources.

If the Village finds a dam which is believed to be in unsafe condition, the Village shall immediately notify the owner of the dam, IDNR/OWR, dam safety section in Bartlett and the Illinois Emergency Management Agency (IEMA).

   I.   Activities That Do Not Require A Registered Professional Engineer's Review: The following activities may be permitted without a registered professional engineer's review. Such activities shall still meet the other requirements of this chapter, including the mitigation requirements.

      1.   Underground and overhead utilities that:

         a.   Do not result in any increase in existing ground elevations, or

         b.   Do not require the placement of aboveground structures in the floodway, or

         c.   In the case of underground stream crossings, the top of the pipe or encasement is buried a minimum of three feet (3') below the existing streambed, and

         d.   In the case of overhead utilities, no supporting towers are placed in the watercourse and are designed in such a fashion as not to catch debris.

      2.   Storm and sanitary sewer outfalls that:

         a.   Do not extend riverward or lakeward of the existing adjacent natural bank slope, and

         b.   Do not result in an increase in ground elevation, and

         c.   Are designed so as not to cause stream erosion at the outfall location.

      3.   Construction of sidewalks, athletic fields (excluding fences), properly anchored playground equipment and patios at grade.

      4.   Construction of shoreline and stream bank protection that:

         a.   Does not exceed one thousand feet (1,000') in length.

         b.   Materials are not placed higher than the existing top of bank.

         c.   Materials are placed so as not to reduce the cross sectional area of the stream channel or bank of the lake.

         d.   Vegetative stabilization and gradual side slopes are the preferred mitigation methods for existing erosion problems. Where high channel velocities, sharp bends or wave action necessitate the use of alternative stabilization measures, natural rock or riprap are preferred materials. Artificial materials such as concrete, construction rubble and gabions should be avoided unless there are no practicable alternatives.

      5.   Temporary stream crossings in which:

         a.   The approach roads will be one-half foot (0.5') or less above natural grade.

         b.   The crossing will allow stream flow to pass without backing up the water above the stream bank vegetation line or above any drainage tile or outfall invert.

         c.   The top of the roadway fill in the channel will be at least two feet (2') below the top of the lowest bank. Any fill in the channel shall be nonerosive material, such as riprap or gravel.

         d.   All disturbed stream banks will be seeded or otherwise stabilized as soon as possible upon installation and again upon removal of construction.

         e.   The access road and temporary crossings will be removed within one year after authorization. (Ord. 17-2866, 1-23-2017)

In SFHAs or floodplains, where no floodways have been identified and no base flood or 100-year frequency flood elevations have been established by FEMA, and draining more than a square mile, no development shall be permitted unless the cumulative effect of the proposals, when combined with all other existing and anticipated uses and structures, shall not significantly impede or increase the flow and passage of the floodwaters nor significantly increase the base flood or 100-year frequency flood elevation.

   A.   Development Permit: No person, firm, corporation, or governmental body, not exempted by State law, shall commence any development in an SFHA or floodplain without first obtaining a development permit from the Village. Application for a development permit shall be made on a form provided by the Village.

The application shall be accompanied by drawings of the site, drawn to scale showing property line dimensions; and existing grade elevations and all changes in grade resulting from excavation or filling, sealed by a licensed engineer, architect or surveyor; the location and dimensions of all buildings and additions to buildings; and the elevation of the lowest floor (including basement) of all proposed buildings subject to the requirements of section 10-11-12 of this chapter.

The application for a development permit shall also include the following information:

      1.   A detailed description of the proposed activity, its purpose, and intended use.

      2.   Site location (including legal description) of the property, drawn to scale, on the designated floodway maps, indicating whether it is proposed to be in an incorporated or unincorporated area.

      3.   Anticipated dates of initiation and completion of activity.

      4.   Plans of the proposed activity shall be provided which include as a minimum:

         a.   A vicinity map showing the site of the activity, name of the waterway, boundary lines, names of roads in the vicinity of the site, graphic or numerical scale, and north arrow;

         b.   A plan view of the project and engineering study reach showing existing and proposed conditions including principal dimensions of the structure or work, elevations in mean sea level (1929 adjustment) datum or NGVD, adjacent property lines and ownership, drainage and flood control easements, distance between proposed activity and navigation channel (when the proposed construction is near a commercially navigable body of water), floodplain limit, location and orientation of cross sections, north arrow, and a graphical or numerical scale;

         c.   Cross section views of the project and engineering study research showing existing and proposed conditions including principal dimensions of the work as shown in plan view, existing and proposed elevations, normal water elevation, 10-year frequency flood elevation, 100-year frequency flood elevation, and graphical or numerical scales (horizontal and vertical); and

         d.   A soil erosion and sedimentation control plan for disturbed areas. This plan shall include a description of the sequence of grading activities and the temporary sediment and erosion control measures to be implemented to mitigate their effects. This plan shall also include a description of final stabilization and revegetation measures, and the identification of a responsible party to ensure postconstruction maintenance.

      5.   Engineering calculations and supporting data shall be submitted showing that the proposed work will meet the criteria of subsection D of this section.

      6.   Any and all other local, State and Federal permits or approvals that may be required for this type of development.

   B.   Development Site Elevation: Based on the best available existing data according to the Illinois State Water Survey's floodplain information repository, the Village Engineer shall compare the elevation of the site to the base flood or 100-year frequency flood elevation. Should no elevation information exist for the site, the developer's engineer shall calculate the elevation according to subsection 10-11-6D of this chapter. Any development located on land that can be shown to have been higher than the base flood elevation as of the site's first flood insurance rate map identification is not in the SFHA and, therefore, not subject to the requirements of this chapter. The Department of Code Enforcement shall maintain documentation of the existing ground elevation at the development site and certification that this ground elevation existed prior to the date of the site's first flood insurance rate map identification.

   C.   Copies Of Other Required Permits: The Department of Code Enforcement shall be responsible for obtaining from the applicant copies of all other local, State, and Federal permits, approvals or permit-not-required letters that may be required for this type of activity. The Village shall not issue the development permit unless all required local, State and Federal permits have been obtained.

   D.   Preventing Increased Damages: No development in the SFHA, where a floodway has not been determined shall create a damaging or potentially damaging increase in flood heights or velocity or threat to public health, safety and welfare or impair the natural hydrologic and hydraulic functions of the floodway or channel, or impair existing water quality or aquatic habitat. Construction impacts shall be minimized by appropriate mitigation methods as called for in this chapter.

   E.   Riverine SFHAs; Standards: Within all riverine SFHAs where the floodway has not been determined, the following standards shall apply:

      1.   Engineering Requirements: The developer shall have a registered professional engineer state in writing and show through supporting plans, calculations, and data that the project meets the engineering requirements of subsections 10-11-9E1 through E13 of this chapter, for the entire floodplain as calculated under the provisions of subsection 10-11-6D of this chapter. As an alternative, the developer should have an engineering study performed to determine a floodway and submit that engineering study to IDNR/OWR for acceptance as a designated floodway. Upon acceptance of their floodway by the department, the developer shall then demonstrate that the project meets the requirements of section 10-11-9 of this chapter for the designated floodway. The "floodway" shall be defined according to the definition in section 10-11-3 of this chapter.

      2.   IDNR/OWR Permit: A development permit shall not be issued unless the applicant first obtains a permit from IDNR/OWR or written documentation that a permit is not required from IDNR/OWR.

      3.   IDNR/OWR Permit Requirement Exception: No permit from IDNR/OWR shall be required if the division has delegated permit responsibility to the Village per 92 Illinois Administrative Code, part 708 or as otherwise recodified for designated floodways, per IDNR/OWR Statewide permit entitled "construction in floodplains with no designated floodways in northeastern Illinois".

      4.   Dam Safety Permits: Any work involving the construction, modification or removal of a "dam" as defined in section 10-11-3 of this chapter shall obtain an IDNR/OWR permit prior to the start of construction of a dam. If the Village finds a dam that does not have an IDNR/OWR permit, the Village shall immediately notify the IDNR/OWR Bartlett Office. If the Village finds a dam which is believed to be in unsafe condition, the Village shall immediately notify the owner of the dam, the IDNR/OWR Bartlett Office, and the Illinois Emergency Management Agency (IEMA).

      5.   Activities Allowed Without Engineer Review: The following activities may be permitted without a licensed professional engineer's review or calculation of base flood elevation and designated floodway. Such activities shall still meet the other requirements of this chapter.

         a.   Bridge and culvert crossings of streams in rural areas meeting conditions of IDNR/OWR Statewide permit number 2.

         b.   Barge fleeting facilities meeting conditions of IDNR/OWR Statewide permit number 3.

         c.   Aerial utility crossings meeting conditions of IDNR/OWR Statewide permit number 4.

         d.   Minor boat docks meeting conditions of IDNR/OWR Statewide permit number 5.

         e.   Minor, nonobstructive activities meeting conditions of IDNR/OWR Statewide permit number 6; activities (not involving fill or positive change in grade) are covered by this permit.

         f.   Outfall structures and drainage ditch outlets meeting conditions of IDNR/OWR Statewide permit number 7.

         g.   Underground pipeline and utility crossings meeting the conditions of IDNR/OWR Statewide permit number 8.

         h.   Bank stabilization projects meeting the conditions of IDNR/OWR Statewide permit number 9.

         i.   Accessory structures and additions to existing residential buildings meeting the conditions of IDNR/OWR Statewide permit number 10.

         j.   Minor maintenance dredging activities meeting conditions of IDNR/OWR Statewide permit number 11.

         k.   Bridge and culvert replacement structures and bridge widenings meeting conditions of IDNR/OWR Statewide permit number 12.

         l.   Temporary construction activities meeting conditions of IDNR/OWR Statewide permit number 13.

         m.   Special uses of public waters meeting conditions of IDNR/OWR Statewide permit number 14.

         n.   Any development determined by IDNR/OWR to be located entirely within a flood fringe area shall be exempt from State floodway permit requirements.

         o.   The flood carrying capacity of any altered or relocated watercourse shall be maintained.

   F.   Compensatory Storage: Whenever any portion of a floodplain is authorized for use, the volume of space which will be occupied by the authorized fill or structure below the base flood or 100-year frequency flood elevation shall be compensated for and balanced by a hydraulically equivalent volume of excavation taken from below the base flood or 100-year frequency flood elevation. The excavation volume shall be at least equal to one and one-fourth (1.25) times the volume of storage lost due to the fill or structure. In the case of streams and watercourses, such excavation shall be made opposite or adjacent to the areas so filled or occupied. All floodplain storage lost below the existing 10-year flood elevation shall be replaced below the proposed 10-year flood elevation. All floodplain storage lost above the existing 10-year flood elevation shall be replaced above the proposed 10-year flood elevation. All such excavations shall be constructed to drain freely and openly to the watercourse. (Ord. 17-2866, 1-23-2017)

This section applies to all proposed development, redevelopment, site modification, building modification or grading within the Village of Western Springs that do not meet the requirements for submittal under article 3 of the WMO. Activities not covered by the requirements of this section include, but are not limited to: driveway repair, fence construction and deck construction under one hundred (100) square feet. A proposed development, redevelopment, site modification, building modification or grading subject to this chapter, but not the WMO, shall not be approved until and unless a grading plan and erosion control plan are submitted and approved as set forth in this section.

   A.   Grading Plan: A stormwater management grading plan showing the proposed grading of the site will be required for all development, redevelopment, site modification, building modification or grading of any property within the Village. The proposed grading of the site must be designed and constructed incorporating Best Management Practices into the site design to minimize increased runoff rates, volumes, and pollutant loads so as to assure that the proposed grading: 1) does not increase the flood or drainage hazards to others; 2) does not create unstable conditions susceptible to erosion; 3) does not increase flood damage to existing and proposed buildings due to stormwater; and 4) accomplishes the other specific purposes listed in subsection 10-11-1D of this chapter.

      1.   A development permit is required for development, redevelopment, site modification, building modification or grading as provided for in this section in the Village.

      2.   An application for a development permit shall be made on a form provided by the Village. An application which does not involve restricting the release rate of stormwater from the site should be accompanied by a stormwater management grading plan.

      3.   The submittal shall include sufficient information to evaluate the environmental characteristics of the property, the potential adverse impacts of the proposed development, redevelopment, site modification, building modification or grading on site water resources both upstream and downstream, and on the adjacent properties; and the effectiveness of the proposed drainage plan with the incorporation of Best Management Practices in managing stormwater runoff and to assure that site modification does not increase the drainage or flood hazard to other properties. "Best Management Practices" are defined as design, construction, and maintenance practices and criteria for stormwater facilities that minimize the impact of stormwater runoff rates and volume, prevent erosion, and capture pollutants.

      4.   The applicant shall certify on the drawings that all clearing, grading, drainage, and construction shall be accomplished in strict conformance with the stormwater management grading plan.

      5.   An application which involves restricting the release rate of stormwater from the site shall be accompanied by both a stormwater management grading plan as described above and a stormwater management detention plan. The stormwater management detention plan shall include design plans and calculations conforming to the requirements listed in subsections B through F of this section. The Village Engineer may impose a site volume control condition on any permit granted pursuant to this section.

   B.   Erosion Control Plan: All applications for a development permit shall be accompanied by a soil erosion and sedimentation control plan for disturbed areas. This plan shall include a description of the sequence of grading activities and the temporary sediment and erosion control measures to be implemented to mitigate their effects. This plan shall also include a description of final stabilization and revegetation measures, and the identification of a responsible party to ensure postconstruction maintenance, and shall also include the following:

      1.   Topographic Map:

         a.   Survey: A topographic survey of the property and areas upstream and downstream necessary to determine off site impacts of the proposed drainage plan at one foot (1') contours. The map shall be keyed to the USGS datum.

         b.   Official Bench Mark System: There is hereby established a system of points or marks of known elevations above the mean sea datum of New York City (NAVD 1988) from which elevations shall hereafter be taken by engineers, surveyors, architects and contractors when making topographical surveys and maps and setting grade and elevations for buildings, pavements, drainage facilities and other structures or work publicly built or regulated by the Village. Those bench marks shall be clearly shown on any pertinent drawings submitted to the Village. It shall be the responsibility of the applicant for a building permit to establish and certify these points unless already established by the Village.

      2.   Environmental Features: A depiction of environmental features of the property and immediate vicinity including the following:

         a.   The limits of wetland areas;

         b.   Any designated natural areas; and

         c.   Any proposed environmental mitigation features.

      3.   Drainage System: A depiction of existing and proposed drainage system features of the property and immediate vicinity including the following information, if applicable:

         a.   The banks and centerline of streams and channels;

         b.   Shoreline of lakes, ponds, and detention basins;

         c.   Farm drains and tiles;

         d.   Watershed boundaries within the property;

         e.   The property's location within stream or river watersheds;

         f.   Location, size and slope of stormwater conduits;

         g.   Sanitary or combined sewers;

         h.   Depressional storage areas;

         i.   Delineation of upstream and downstream drainage features and watersheds which might be affected by the development;

         j.   Detention facilities;

         k.   Roads and streets and associated stormwater inlets;

         l.   Base flood elevation, and designated floodway where identified for the property; and

         m.   Basis of design for the final drainage network components.

   C.   Detention:

      1.   The maximum available storage to be provided in a detention basin shall be based on the runoff from the 100-year, 24-hour event and reservoir (also called modified plus or level pool) routing or equivalent.

         a.   Wet Basins: Wet detention basins shall be designed to remove stormwater pollutants, to be safe, to be aesthetically pleasing, and as much as feasible to be available for recreational use.

            (1)   Wet Basin Depths: Wet basins shall be at least three feet (3') deep, excluding nearshore banks and safety ledges. If fish habitat is to be provided they shall be at least ten feet (10') deep over twenty five percent (25%) of the bottom area to prevent winter freeze out.

            (2)   Permanent Pool Volume: The permanent pool volume in a wet basin at normal depth shall be equal to the runoff volume from its watershed for the 2-year event.

            (3)   Nuisance Control: Wet basins shall be designed in a manner which will reduce as much as practicable nuisance problems such as algae and waterfowl.

         b.   Dry Basins: Dry basins shall be designed to remove stormwater pollutants, to be safe, to be aesthetically pleasing and as much as feasible to be available for multiple uses.

            (1)   Dry Basin Drainage: Dry basins shall be designed so that eighty percent (80%) of their bottom area shall have standing water no longer than seventy two (72) hours for any runoff event less than the 100-year event. Underdrains directed to the outlet control shall be used if required to accomplish this requirement.

            (2)   Dry Basin Water Quality: All dry detention basins shall be designed to remove stormwater pollutants. Peak dry detention basin release rate shall be no greater than ten one-hundredths (0.10) cfs per acre for all runoff volumes less than or equal to the runoff from the 100-year, 24-hour rainfall for the developed property.

      2.   Streets: Streets are not to be used for the storage of excess stormwater, ponding depths shall not encroach more than three feet (3') on the adjacent traffic lane and shall not remain flooded for more than eight (8) hours for any event less than or equal to the 100-year event.

      3.   Safety: The drainage system components, especially all detention basins, shall be designed to protect the safety of any children or adults coming in contact with the system during runoff events.

         a.   Shorelines: The shorelines of all detention basins at 100-year capacity shall be as level as practicable to prevent accidental falls into the basin and for stability and ease of maintenance. Shorelines shall not have greater than three to one (3:1) (horizontal to vertical) slope.

         b.   Banks: The side slopes of the banks of both wet and dry detention basins shall not be steeper than three to one (3:1).

         c.   Safety Ledge: All wet detention basins shall have a level safety ledge extending ten feet (10') into the basin from the shoreline and three feet (3') below the normal water depth. The ledge shall be pitched to the shoreline at four percent (4%).

         d.   Velocity: Velocities throughout the drainage system shall be controlled to safe levels taking into consideration rates and depths of flow.

         e.   Overflow Structures: All stormwater detention basins shall be provided with an overflow structure capable of safely passing flows from the probable maximum storm. The elevation of the overflow structure shall be at six inches (6") above the high water level of the basin. The elevations of emergency overflow structure shall be nine inches (9") above the high water level.

      4.   Infiltration Practices: Infiltration practices including basins, trenches, and porous pavement shall only be allowed in soils considered "A" or "B" by the U.S. Soil Conservation Service. Infiltration practices shall not be located within seventy five feet (75') of a water supply well or a building foundation. A sediment settling basin shall be provided to remove coarse sediment from stormwater flows before they reach infiltration basins or trenches. Stormwater shall not be allowed to stand more than seventy two (72) hours over eighty percent (80%) of a dry basin's bottom area for the maximum design event to be exfiltrated. The bottom of infiltration facilities shall be a minimum of four feet (4') above seasonally high ground water and bedrock.

      5.   Detention In Floodplains: The placement of detention basins within the floodplain is strongly discouraged because of questions about their reliable operation during flood events. However, the stormwater detention requirements of this chapter may be fulfilled by providing detention storage within flood fringe areas on the project site provided the following provisions are met:

         a.   Detention In Flood Fringe Areas: The placement of a detention basin in a flood fringe area shall require compensatory storage for one and one-fourth (1.25) times the volume below the base flood elevation occupied by the detention basin including any berms. The release from the detention storage provided shall still be controlled consistent with the requirements of subsection C1b(2) of this section.

The applicant shall certify its operation for all stream flow and floodplain backwater conditions. Excavations for compensatory storage along streams and watercourses shall be opposite or adjacent to the area occupied by detention. All floodplain storage lost below the 10-year flood elevation shall be replaced below the 10-year flood elevation. All floodplain storage lost above the existing 10-year flood elevation shall be replaced above the proposed 10-year flood elevation. All compensatory storage excavations shall be constructed to drain freely and openly to the watercourse.

         b.   Detention Basins In Floodways: Detention basins shall not be placed in the floodway.

         c.   On Stream Detention: On stream detention basins are allowable if they provide regional public benefits and if they meet the other provisions of this chapter with respect to water quality and control of the events less than or equal to the 100-year, 24-hour event from the property. Further discussion is presented in subsection C6 of this section. If on stream detention is used for watersheds larger than one square mile, it is recommended that the applicant use dynamic modeling to demonstrate that the design will not increase stage for any properties upstream or downstream of the property. Also, impoundment of the stream as part of on stream detention:

            (1)   Shall not prevent the migration of indigenous fish species, which require access to upstream areas as part of their life cycle, such as for spawning;

            (2)   Shall not cause or contribute to the degradation of water quality or stream aquatic habitat;

            (3)   Shall include a design calling for gradual bank slopes, appropriate bank stabilization measures, and a presedimentation basin; and

            (4)   Shall comply with 92 Illinois Administrative Code part 708 or as otherwise recodified and the other appropriate sections of this chapter.

      6.   Water Quality:

         a.   Length To Width Ratio: All detention basins shall have a length to width ratio of at least three to one (3:1) as measured along the longitudinal axis of flow.

         b.   Inlet And Outlet Orientation: As much as feasible, the distance between detention inlets and outlets shall be maximized. If possible, they should be at opposite ends of the basin.

         c.   Velocity Dissipation: Baffles or berms should be placed perpendicular to the direction of flow through a detention basin to reduce velocity and prevent scour.

      7.   Maintenance: The stormwater drainage system shall be designed to minimize and facilitate maintenance. Turfed side slopes shall be designed to allow lawn mowing equipment to easily negotiate them. Wet basins shall be provided with alternate outflows which can be used to completely drain the pool for sediment removal. Presedimentation basins shall be considered for localizing sediment deposition and removal. Access for heavy equipment shall be provided.

      8.   Detention In Wetlands:

         a.   Modifications; Compliance With Regulations: Existing wetlands shall not be modified for the purposes of stormwater detention unless it is demonstrated that the existing wetland is low in quality and the proposed modifications will maintain or improve its habitat and water quality.

            (1)   In addition, fill shall not be placed in the wetland and a long term monitoring and maintenance agreement shall be established to ensure that the modified wetland/detention facility continues to provide wetland functions.

         b.   Protection Of Wetlands: Wetlands shall be protected from the adverse changes in runoff quality and quantity associated with land developments. In addition to the other requirements of this chapter, the following mitigation criteria shall be met for all developments whose drainage flows into wetlands:

            (1)   The existing wetland shall be protected during construction by appropriate soil erosion and sediment control measures and shall not be filled.

            (2)   All runoff from the development shall be routed through a preliminary detention/sedimentation basin designed to capture the 2-year, 24-hour event and hold it for at least twenty four (24) hours, before being discharged to the wetland. This basin shall be constructed before property grading begins. In addition, the drainage hierarchy defined in subsection 10-11-1E of this chapter should be followed to minimize runoff volumes and rates being discharged to the wetland.

            (3)   A buffer strip of at least twenty five feet (25') in width, preferably vegetated with native plant species, shall be maintained around the periphery of the wetland.

   D.   Flows From Tributary Areas: Stormwater runoff from areas tributary to the property shall be considered in the design of the property's drainage system.

      1.   Upstream Areas Not Meeting Requirements Of This Chapter: When there are areas not meeting the storage and release rates of this chapter, tributary to the applicant's property, regionalized detention on the applicant's property shall be explored by the applicant. The following steps shall be followed:

         a.   The applicant shall compute the storage volume needed for his property using the release rates of subsection C1b(2) of this section, the applicant's property area and the procedures described in subsection 10-11-7H, 10-11-9E2 or 10-11-10F of this chapter as applicable.

         b.   Areas tributary to the applicant's property, not meeting the storage and release rate requirements of this chapter shall be identified.

         c.   Using the areas calculated in subsections D1a and D1b of this section shall be added together to determine total storage required.

Allowable release rates shall be computed using the combined property areas. Storage shall be computed as described in subsection C of this section. If tributary areas are not developed, a reasonable fully developed land cover shall be assumed for the purposes of computing storage.

Once the necessary combined storage is computed, the Village may choose to pay for oversizing the applicant's detention basin to accommodate the regional flows. The applicant's responsibility will be limited to the storage for his property as computed in subsection D1a of this section.

If regional storage is selected by the Village, then the design produced in subsection D1c of this section shall be implemented.

If regional storage is rejected by the Village the applicant must route them through his basin. The peak release rate for the applicant's property will not be exceeded given the combined inflow of the areas determined in subsection D1b of this section plus the applicant's property until the required storage calculated in subsection D1a of this section has been provided. The overflow structure must be designed to accommodate the maximum bypass flows after the required storage has been provided.

      2.   Upstream Areas Meeting Requirements Of This Chapter: When there are areas which meet the storage and release rate requirements of this chapter tributary to the applicant's property, the upstream flows shall either be bypassed around the applicant's detention basin or be routed through the applicant's detention basin at the discretion of the Village. Storage needed for the applicant's property shall still be computed as described in subsection D1a of this section. However, if the Village decides to route tributary area flows through an applicant's basin, the design stormwater final releases shall be based on the combined total of the applicant's restricted releases plus tributary areas restricted releases.

   E.   Early Completion Of Detention Facilities: Where detention, retention, or depressional storage areas are to be used as part of the drainage system for a property, they shall be completed before general property grading begins. This is to ensure that if soil erosion and sediment control practices are not adequately implemented, any eroded sediment will be captured in these areas and will have to be removed by the applicant before project completion.

   F.   Maintenance: Maintenance of stormwater drainage facilities located on private property shall be the responsibility of the owner of that property. Before the appropriate permit is obtained from the Village, the applicant shall execute a maintenance agreement with the Village guaranteeing that the applicant and all future owners of the property will maintain its stormwater drainage system.

The maintenance agreement shall also specifically authorize representatives of the Village to enter onto the property for the purpose of inspections of the drainage system. Such agreement shall be recorded with the Recorder of Deeds of Cook County. The maintenance agreement shall include a schedule for regular maintenance of each aspect of the property's stormwater drainage system and shall provide for access to the system for inspection by authorized personnel of the Village. The maintenance agreement shall also stipulate that if the appropriate authorized personnel of the Village notify the property owner in writing of maintenance problems which require correction, the property owner shall make such corrections within thirty (30) calendar days of such notification. If the corrections are not made within this time period, the Village may have the necessary work completed and assess the cost to the property owner.

The Village has the option of requiring a bond to be filed by the property owner for maintenance of the stormwater drainage system.

   G.   Inspections During Construction: General site grading shall not begin until the Department of Code Enforcement of the Village has certified in writing to the applicant that any necessary detention facilities are in place and operational. The Department of Code Enforcement or his representative will also conduct periodic inspections of the work in progress to be certain that the drainage system is being built as designed. If any violations of the provisions or requirements of this chapter are noted during such inspections, the Village shall notify the property owner in writing of the items needing correction.

The property owner shall have ten (10) calendar days to make such corrections unless given a specific extension of time in writing by the Village. Failure to complete such corrections within the specified time period shall constitute a violation of this chapter.

   H.   Final Inspection: Upon notification by the applicant that the drainage system is completed, the Department of Code Enforcement shall conduct a final inspection. If the drainage system is found to contain deficiencies which require correction, the Department of Code Enforcement shall notify the property owner of the necessary corrections. The property owner shall correct such deficiencies within ten (10) calendar days unless given a specific extension of time in writing by the Department of Code Enforcement. Failure to make necessary corrections within the specified time period shall constitute a violation of this chapter. Upon finding that the drainage system meets the provisions and requirements of this chapter, the Department of Code Enforcement shall issue in writing a notice of drainage system completion to the property owner.

   I.   Routine Inspections: All privately owned drainage systems shall be inspected by representatives of the Village not less often than once per year. A written report shall be filed of the results of any inspection and a copy sent to the property owner detailing any problems which need correction. (Ord. 17-2866, 1-23-2017)

In addition to the requirements found in sections 10-11-7, 10-11-9, and 10-11-10 of this chapter for development in flood fringes, designated floodways, and SFHA or floodplains where no floodways have been identified (Zones A, AO, AH, AE, A1-A30, A99, VO, V1-30, VE, V, M, E, D or X), the following requirements shall be met:

   A.   Public Health Standards:

      1.   No developments in the SFHA shall include locating or storing chemicals, explosives, buoyant materials, animal wastes, fertilizers, flammable liquids, pollutants or other hazardous or toxic materials below the FPE.

      2.   New and replacement water supply systems, wells, sanitary sewer lines and on site waste disposal systems may be permitted providing all manholes or other aboveground openings located below the FPE are watertight.

   B.   Carrying Capacity And Notification: For all projects involving channel modification, fill, or stream maintenance (including levees), the flood carrying capacity of the watercourse shall be maintained. In addition, the Village shall notify adjacent communities in writing thirty (30) days prior to the issuance of a permit for the alteration or relocation of the watercourse.

   C.   Protecting Buildings: All new construction located within a 100-year floodplain, also known as an SFHA, shall be protected from flood damage below the flood protection elevation. New construction located within a designated floodway shall also meet the more restrictive appropriate use standards included in section 10-11-9 of this chapter. All new construction in or within one hundred feet (100') of an SFHA shall upon completion submit to the Village, an NFIP elevation certificate, in accordance with the NFIP guidelines.

      1.   This building protection criteria applies to the following situations:

         a.   Construction or placement of a new building;

         b.   A structural alteration to an existing building that either increases the first floor area by more than twenty percent (20%) or the building's market value by more than fifty percent (50%);

         c.   Installing a manufactured home on a new site or a new manufactured home on an existing site. This building protection requirement does not apply to returning a mobile home to the same site it lawfully occupied before it was removed to avoid flood damage; and

         d.   Installing a travel trailer on a site for more than one hundred eighty (180) days.

      2.   This building protection requirement may be met by one of the following methods:

         a.   A residential or nonresidential building, when allowed, may be constructed on permanent landfill in accordance with the following:

            (1)   The lowest floor, (including basement) shall be at or above the flood protection elevation.

            (2)   The fill shall be placed in layers no greater than one foot (1') deep before compaction and should extend at least ten feet (10') beyond the foundation of the building before sloping below the flood protection elevation. The top of the fill shall be above the flood protection elevation. However, the ten foot (10') minimum may be waived if a structural engineer certifies an alternative method to protect the building from damages due to hydrostatic pressures. The fill shall be protected against erosion and scour. The fill shall not adversely affect the flow or surface drainage from or onto neighboring properties.

         b.   A residential or nonresidential building may be elevated in accordance with the following:

            (1)   Building or improvements shall be elevated on crawl space, stilts, piles, walls or other foundation that is permanently open to floodwater and not subject to damage by hydrostatic pressures of the base flood or 100-year frequency flood.

            (2)   The permanent openings shall be no more than one foot (1') above grade, and consists of a minimum of two (2) openings. The openings must have a total net area of not less than one square inch for every one square foot of enclosed area subject to flooding below the base flood elevation.

            (3)   The foundation and supporting members shall be anchored and aligned in relation to flood flows and adjoining structures so as to minimize exposure to known hydrodynamic forces such as current, waves, ice and floating debris.

            (4)   All areas below the flood protection elevation shall be constructed of materials resistant to flood damage. The lowest floor (including basement) and all electrical, heating, ventilating, plumbing, and air conditioning equipment and utility meters shall be located at or above the flood protection elevation. Water and sewer pipes, electrical and telephone lines, submersible pumps, and other waterproofed service facilities may be located below the flood protection elevation provided they are waterproofed.

            (5)   No area below the flood protection elevation shall be used for storage of items or materials.

            (6)   Manufactured homes and travel trailers to be installed on a site for more than one hundred eighty (180) days, shall be elevated to or above the flood protection elevation; and, shall be anchored to resist flotation, collapse, or lateral movement by being tied down in accordance with the rules and regulations for the Illinois Mobile Home Tiedown Act issued pursuant to 77 Illinois Administrative Code 870.

         c.   Only a nonresidential building may be structurally floodproofed (in lieu of elevation) provided that a registered professional engineer shall certify that the building has been structurally dry floodproofed below the flood protection elevation, the structure and attendant utility facilities are watertight and capable of resisting the effects of the base flood or 100-year frequency flood.

            (1)   The building design shall take into account flood velocities, duration, rate of rise, hydrostatic and hydrodynamic forces, the effects of buoyancy, and impacts from debris or ice.

            (2)   Floodproofing measures shall be operable without human intervention and without an outside source of electricity. (Levees, berms, floodwalls and similar works are not considered floodproofing for the purpose of this subsection.)

         d.   Nonconforming structures located in a designated floodway may remain in use, but may not be enlarged, replaced or structurally altered. A nonconforming structure damaged by flood, fire, wind or other natural or manmade disaster may be restored unless the damage exceeds fifty percent (50%) of its market value before it was damaged, in which case it shall conform to this chapter. (Ord. 17-2866, 1-23-2017)

The Village Board shall take into account flood hazards to the extent that they are known in all official actions related to land management, use and development.

   A.   New subdivisions, manufactured home parks, annexation agreements, and planned unit developments (PUDs) within the SFHA shall be reviewed to assure that the proposed developments are consistent with sections 10-11-7 through 10-11-12 of this chapter and the need to minimize flood damage. Plats or plans for new subdivisions, mobile home parks and planned unit developments (PUDs) shall include a signed statement by a registered professional engineer that the plat or plans account for changes in the drainage of surface waters in accordance with the Plat Act.

   B.   Proposals for new subdivisions, manufactured home parks, travel trailer parks, planned unit developments (PUDs) and additions to manufactured home parks and additions to subdivisions shall include base flood or 100-year frequency flood elevation data and floodway delineations. Where this information is not available from an existing study filed with the Illinois State Water Survey, the applicant's engineer shall be responsible for calculating the base flood or 100-year frequency flood elevation per subsection 10-11-6D of this chapter and the floodway delineation per the definition in section 10-11-3 of this chapter and submitting it to the State Water Survey and IDNR/OWR for review and approval as best available regulatory data.

   C.   Streets, blocks, lots, parks and other public grounds shall be located and laid out in such a manner as to preserve and utilize natural streams and channels. Wherever possible, the floodplains shall be included within parks or other public grounds.

   D.   The Village Board shall not approve any planned unit development (PUD) or plat of subdivision located outside the corporate limits unless such agreement or plat is in accordance with the provisions of this chapter. (Ord. 17-2866, 1-23-2017)

No variances from the WMO shall be granted by the Village without district approval. No variances from this chapter shall be granted by the Village to any development located in a "designated floodway" as defined in section 10-11-3 of this chapter. However, when a development proposal is located outside of a designated floodway, and whenever the standards of this chapter place undue hardship on a specific development proposal, the applicant may apply to the Zoning Board of Appeals for a variance. The Zoning Board of Appeals shall review the applicant's request for a variance and shall submit its recommendation to the Village Board.

   A.   Appeal Board:

      1.   The Western Springs Zoning Board as established by the Village shall hear requests for variances from the requirements of this chapter or instances in which it is alleged there is an error in any requirement, decision or determination made by the Village Engineer in the enforcement or administration of this chapter and shall make a recommendation regarding such variance to the Village Board.

      2.   In passing upon such applications, the Western Springs Zoning Board and Village Board shall consider all technical evaluations, all relevant factors, standards specified in other sections of this chapter, and the:

         a.   Danger that materials may be swept into other lands to the injury of others;

         b.   Danger to life and property due to flooding or erosion damage;

         c.   Susceptibility of the proposed facility and its contents to flood damage and the effect of such damage on the individual owner;

         d.   Importance of the services provided by the proposed facility to the community;

         e.   Necessity to the facility of a waterfront location, where applicable;

         f.   Availability of alternative locations for the proposed use which are not subject to flooding or erosion damage;

         g.   Compatibility of the proposed use with existing and anticipated development;

         h.   Relationship of the proposed use of the Comprehensive Plan and Floodplain Management Program of that area;

         i.   Safety of access to the property in times of flood for ordinary and emergency vehicles;

         j.   Expected heights, velocity, duration, rate of rise, and sediment transport of the floodwaters and the effects of wave action, if applicable, expected at the site; and the

         k.   Costs of providing governmental services during and after flood conditions, including maintenance and repair of public utilities and facilities such as sewer, gas, electrical and water systems, and streets and bridges.

      3.   Upon consideration of the factors of subsection A2 of this section and the purpose of this chapter, the Western Springs Zoning Board may recommend and the Village Board may attach such conditions to the granting of variances as it deems necessary to further the purpose of this chapter.

      4.   The Village Engineer shall maintain the records of all appeal actions, including technical information, and report any variances to the Federal Insurance Administration upon request.

   B.   Conditions For Variances:

      1.   Generally, variances may be issued for new construction and substantial improvements to be erected on a lot of record one- half (1/2) acre or less in size, contiguous to and surrounded by lots with existing structures constructed below the base flood level, providing items in this section have been fully considered. As the lot increases beyond one-half (1/2) acre, the technical justification required for issuing the variance increases.

      2.   Variances may be issued for the reconstruction, rehabilitation or restoration of structures listed in the National Register of Historic Places or the State Inventory of Historic Places, without regard to the procedures set forth in the remainder of this section.

      3.   Variance shall not be granted unless the applicant demonstrates that:

         a.   The development activity cannot be located outside the SFHA;

         b.   An exceptional hardship would result if the variance were not granted;

         c.   The relief requested is the minimum necessary;

         d.   There will be no additional threat to public health or safety or creation of a nuisance;

         e.   There will be no additional public expense for flood protection, rescue or relief operations, policing, or repairs to roads, utilities, or other public facilities;

         f.   The provisions of subsection 10-11-7F of this chapter are met; and

         g.   The provisions of subsection 10-11-10D of this chapter are met.

      4.   The Village shall notify an applicant in writing that a variance from the requirements of this chapter that would lessen the degree of protection to a building will:

         a.   Result in increased premium rates for flood insurance up to amounts that may be as high as twenty five dollars ($25.00) for one hundred dollars ($100.00) of insurance coverage;

         b.   Increase the risks to life and property; and

         c.   Require that the applicant proceed with knowledge of these risks and that the applicant acknowledge in writing the assumption of the risk and liability.

Variances requested in connection with restoration of a site or building listed on the National Register of Historical Places or documented as worthy of preservation by the Illinois Historic Preservation Agency may be granted using criteria more permissive than the requirements of subsections A and B of this section. (Ord. 17-2866, 1-23-2017)

The degree of flood protection required by this chapter is considered reasonable for regulatory purposes and is based on available information derived from engineering and scientific methods or study. Larger floods may occur or flood heights may be increased by manmade or natural causes. This chapter does not imply that development, either inside or outside of the SFHA, will be free from flooding or damage. This chapter does not create liability on the part of the Village or any officer or employee thereof for any flood damage that results from reliance on this chapter or any administrative decision made lawfully thereunder. (Ord. 17-2866, 1-23-2017)

Failure to comply with the requirements of this chapter or to obtain a permit for development in the SFHA or failure to comply with the requirements of a permit or conditions of a variance resolution shall be deemed to be a violation of this chapter. Upon due investigation, the Village Attorney may determine that a violation of the minimum standards of this chapter exist. The Village Attorney shall notify the owner in writing of such violation.

   A.   If such owner fails after ten (10) days' notice to correct the violation:

      1.   The Village may make application to the Circuit Court for an injunction requiring conformance with this chapter or make such other order as the court deems necessary to secure compliance with this chapter.

      2.   Any person who violates this chapter shall upon conviction thereof be fined not less than fifty dollars ($50.00) nor more than one thousand dollars ($1,000.00).

      3.   A separate offense shall be deemed committed upon each day during or on which a violation occurs or continues.

      4.   The Village may record a notice of violation of this chapter to the property.

   B.   The Village shall inform the owner that any such violation is considered a willful act to increase flood damages and, therefore, may cause coverage by a standard flood insurance policy to be suspended.

   C.   Nothing herein shall prevent the Village from taking such other lawful action to prevent or remedy any violations. All costs connected therewith shall accrue to the person or persons responsible. (Ord. 17-2866, 1-23-2017)

This chapter is not intended to repeal, abrogate or impair any existing easements, covenants, or deed restrictions. Where this chapter and other chapters, easements, covenants or deed restrictions conflict or overlap, whichever imposes the more stringent restrictions shall prevail. This chapter is intended to repeal the original chapter or resolution which was adopted to meet the National Flood Insurance Program regulations, but is not intended to repeal the resolution which the Village passed in order to establish initial eligibility for the program. (Ord. 17-2866, 1-23-2017)