Chapter 15.36 FLOOD DAMAGE PREVENTION

The purpose of this article is to diminish threats to public health and safety caused by floodwaters; reduce economic losses to individuals and the community at large; enhance broader social and economic objectives; protect, conserve and promote the orderly development of land and water resources; prevent victimizations and fraud; and to comply with the guidelines for the National Flood Insurance Program as published by the U.S. Department of Housing and Urban Development. The provisions of this article further regulate, guide and control:

A. The use, subdivision, layout and improvement of lands located in floodplains;

B. The excavating, filling and grading of lots and other land parcels or areas located in floodplains and the storing of certain materials thereon;

C. The location, construction and elevation of buildings and other structures or parts or appurtenances thereof, and of sanitary and storm sewers and appurtenances, such as manholes, located in floodplains.

15.36.020 Definitions.

For the purposes of this article, the following definitions are adopted:

A. “Area of special flood hazard” means the land which is subject to a one percent chance of flooding annually. This area may also be identified as that which is subject to the one-hundred-year flood. The area is designated as Zone A, A1-99, AH or AO on the maps provided by the Federal Insurance Administration.

B. “Base flood” means the flood having a one percent chance of being equaled or exceeded in any given year. The base flood is also known as the one-hundred-year flood. If the one-hundred-year flood information is not available, the base flood shall be the flood of record.

C. “Base flood area” means the land area subject to inundation by waters of the base flood.

D. “Base flood elevation” means the highest water surface elevation of the base flood.

E. “Compensatory storage” means an artificially excavated volume of storage within the base flood area 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.

F. “Development” means any manmade change to improved or unimproved real estate, including but not limited to construction of or substantial improvements to buildings or other structures, the placement of mobile homes, mining, dredging, filling, grading, paving, excavation or drilling operations.

G. “Flood” means the condition existing when the waters of any watercourse, pond or depression temporarily rise to a height above their normal levels and overflow the boundaries within which they are ordinarily contained. It also includes the unusual rapid accumulation or runoff of surface waters.

H. “Flood frequency” means a period of years, based on a statistical analysis, during which a flood of a stated magnitude may be expected to be equaled or exceeded.

I. “Flood fringe” means the higher portion of the floodplain, immediately adjacent to and on either side of the floodway, occupied by quiescent or slow-moving waters during floods.

J. “Flood hazard boundary map (FHBM)” means an official map of the village, issued or approved by the Administrator of the Federal Insurance Administration, on which the areas having special flood hazards have been drawn and designated as Zone A.

K. “Flood insurance study (FIS)” means an examination and evaluation of hydraulic data sponsored by the Federal Insurance Administration to determine base flood flows, elevations, areas and floodways. The FIS also determines flows, elevations and areas of floods having lesser and greater frequencies of occurrence.

L. “Flood of record” means an actual historical flood event for which sufficient records are available to establish its extent. No uniform probability of occurrence is associated with floods of record. However, the probability of occurrence may be determined for the event at specific locations.

M. “Floodplain” means the special flood hazard lands adjoining a watercourse, whose surface elevation is lower than the base flood elevation, that are subject to periodic inundation during floods.

N. “Flood profile” means graphical representations of the elevations of the water surface of the one-hundred-year flood along the watercourses of the village.

O. “Floodproofing” means modifications to structures made to reduce flood damages. Those changes may be made to existing structures or incorporated in the design of new structures. In all instances, floodproofing must be watertight and must be adequate without the need for human intervention.

P. “Flood protection elevation” means the elevation to which uses regulated by this article are required to be elevated or floodproofed.

Q. Flood Return Period. Same as “flood frequency.”

R. “Floodway” means the channel of a watercourse and those portions of the adjoining floodplains which are required to carry and discharge the one-hundred-year flood with no significant increase in the base flood elevation.

S. “Floodway encroachment lines” means the lateral boundaries of the floodway which separate it from the flood fringes.

T. “Freeboard” means the 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 may be caused by ice or debris jams.

U. “Hydrostatic uplift” means the upward pressure exerted on floorslabs or an entire structure by standing water or groundwater, which tends to float a structure or crack the floor. It is based on the difference in elevation between the surface level of the water. Hydrostatic pressure may also be horizontal, imposing forces on walls causing them to crack or fail.

V. “Mobile home” means a structure transportable in one or more sections, which is built on a permanent chassis and designed to be used with or without a permanent foundation when connected to the required utilities. It does not include recreational vehicles or travel trailers.

W. “Mobile home park” means a parcel or contiguous parcels of land which has been so designed and improved that it contains two or more mobile home lots available to the general public for sale or rent and the placement thereon of mobile homes for occupancy.

X. “One-hundred-year flood” means a flood magnitude with a one percent statistical chance of being equaled or exceeded during any year. A flood this large would be reached once during a one-hundred-year period, on the average. However, the occurrence of such an event does not diminish the chance of its recurring again at any time.

Y. “Risk premium rate zones” means flood hazard areas designated according to the degree of flooding they would experience during the base flood. The symbols used to designate these zones are as follows:


Zone Symbol
A	Area of special flood hazard without water surface elevations determined.
A1-99	Area of special flood hazard with water surface elevations determined.
AH	Area of special flood hazards having a level water surface (ponding) with water depths between one and three feet.
AO	Area of special flood hazards having a sloping water surface (sheet runoff) with water depths between one and three feet.
VO	Area of special flood hazards having shallow water depths and/or unpredictable flow paths between one and three feet and with velocity.
B	Area of moderate flood hazards.
C	Area of minimal hazards.

Z. “Riverine” means relating to, formed by, or resembling a river (including tributaries), stream, creek or brook.

AA. “Structure” means a walled or roofed building, including a gas or liquid storage tank, that is principally above ground, as well as a mobile home.

BB. “Substantial improvement” means any repair, reconstruction or improvement of a structure, the cost of which equals or exceeds fifty percent of the market value of the structure either before the improvement or repair is started, or if the structure has been damaged and is being restored, before the damage occurred. The term does not, however, include either: (1) any project for improvement of a structure to comply with existing state or local health, sanitary or safety code specifications which are solely necessary to assume safe living conditions, or (2) any alteration of a structure or site documented as deserving preservation by the Illinois Department of Conservation or listed on the National Register of Historic Places.

CC. “Watercourse” means any river, stream, creek, brook, branch or other drainage in or into which storm water runoff and floodwaters flow either regularly or intermittently.

15.36.030 Compliance with other applicable regulations.

Before starting any of the work regulated by this article, an applicant shall comply with the requirements set forth in other applicable ordinances with respect to the submission and approval of preliminary and final subdivision plats, improvement plans, building and zoning permits, inspections, appeals and similar matters, along with those set forth in this article and as may be required by federal or state laws and the regulations of any department of the state. Where provisions of this article are more restrictive than other requirements, this article shall apply.

15.36.040 General conditions.

The general conditions set out in RMC 15.36.050 through 15.36.270 shall apply in RMC 15.36.280 through 15.36.420.

15.36.050 Floodways.

In floodways which have been identified in RMC 15.36.130 as elements of floodplains associated with the flood having a one-hundred-year recurrence interval, fill, encroachments and new construction and substantial improvements of existing structures, which would result in any increase in flood heights, shall be prohibited. The location of any portion of a new mobile home park, of any expansion to an existing mobile home park, and of any mobile home not in a mobile home park shall be prohibited in the floodway.

15.36.060 Flood fringes.

In flood fringes which have been identified in RMC 15.36.130 as elements of the floodplains associated with floods having a one-hundred-year recurrence interval, construction, filling or use of those low-lying lands may be permitted under the conditions specified in RMC 15.36.280 through 15.36.420.

15.36.070 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 elevation shall be compensated for and balanced by at least an equal volume of excavation taken from below the base flood elevation. In the case of streams or watercourses, such excavation shall be made opposite or immediately adjacent to the areas so filled or occupied. All such excavations should be constructed to drain freely and openly to the watercourse.

15.36.080 Watercourse alteration.

In riverine situations, the village board shall notify adjacent communities, the Illinois Division of Water Resources and the Federal Insurance Administration prior to any alteration or relocation of a watercourse within the municipality’s jurisdiction by any person or agencies. The village commission shall assure that the flood carrying capacity within the altered or relocated portion of any watercourse be maintained.

15.36.090 Freeboard.

All structures located in base flood areas shall be required to be so sited on fill or be otherwise designed and constructed so as to include a freeboard of at least one foot between the lowest floor and the base flood elevation, except as provided for in RMC 15.36.450 through 15.36.510.

15.36.100 Base flood.

Wherever the areas expected to be inundated by the base flood have been specifically identified, it is the intention of this article to provide protection in those areas against the high waters of that flood.

15.36.110 Historical flood of record.

In the absence of specific information pertaining to the base flood, it is the intention of this article to provide protection in the low-lying areas of the community against the high waters of the historical flood of record.

15.36.120 Land use controls.

This floodplain article is not intended to reduce or eliminate existing flooding, nor is it intended to impose a complete prohibition of construction in base flood areas. On the contrary, these regulations are designed to guide and control development in such a manner as to lessen the damaging effects of floods on developments proposed for the low-lying areas of the community.

15.36.130 Village maps.

Official maps which depict the floodplains, floodways, floodway fringes and floodway encroachment lines are available for inspection in the offices of the village, are identified as parts of this article, are incorporated herein and are identified as follows:

A. Certified HUD Flood Insurance Studies (FIS);

B. Illinois Department of Transportation – Division of Water Resources Regulatory Floodplain Maps and Profiles;

C. Soil Conservation Services (SCS) – Metropolitan Sanitary District of Greater Chicago (MSDGC) Floodplain Information Maps and Profiles.

15.36.140 Flood profiles.

Flood profiles describing the expected elevation of floods along the centerlines of the principal watercourses of the village are available for inspection in the offices of the village, are identified as parts of this article, are incorporated herein and are identified as follows:

A. Certified HUD Flood Insurance Studies (FIS);

B. Illinois Department of Transportation – Division of Water Resources Regulatory Floodplain Maps and Profiles;

C. Soil Conservation Services (SCS) – Metropolitan Sanitary District of Greater Chicago (MSDGC) Floodplain Information Maps and Profiles;

D. USGS Maps of Flood-Prone Areas;

E. USGS-NIPC Hydrologic Investigation Atlases (Floods of Record).

15.36.150 Conflicts between maps and profiles.

In the event a conflict arises between the information depicted by the official floodplain maps and the official village profiles, and in the absence of any overriding information to the contrary, the data prescribed by the profiles will govern.

15.36.160 Official elevations.

The system of official benchmarks and elevations already established in the area by the U.S. Coast and Geodetic Survey (first order level network) or the U.S. Geological Survey shall hereafter be taken by engineers, surveyors, architects and contractors when making topographical surveys and maps, and when setting grades and elevations of buildings, pavements, drainage facilities and other structures or works publicly constructed or regulated by the village.

15.36.170 Determination of base flood area location and elevations.

The official maps described in this section shall be used as an aid in determining whether a specific parcel of land lies within the base flood area. The final decision, however, shall be based on the relation of the surveyed ground elevation and the base flood elevation. For the purposes of this article, the base flood elevation applicable to a specific parcel of land, if not otherwise depicted by the official maps and profiles described in RMC 15.36.130 and 15.36.140, shall be that elevation established for an adjoining stream or channel measured at right angles to the general direction of flow in that stream or channel. In riverine situations where a bend in the stream exists and more than one line can be placed at right angles to the parcel of land, the highest base flood elevation determined shall prevail.

15.36.180 Unnumbered A zones.

In unnumbered A zones, in the absence of FIA base flood elevation data, consider other available data as the basis for elevating residential structures to or above base flood level, and floodproofing or elevating nonresidential structures to or above base flood level. The “other available data” shall be the maps listed in RMC 15.16.140, and are listed in descending order of preference.

15.36.190 Encroachment limit.

The regulatory floodways depicted on the official maps have designated an encroachment limit which will not increase the base flood elevation more than one-tenth foot.

15.36.200 Variances – Generally.

The village board may grant variances from the regulatory standards of this article in accordance with the requirements of RMC 15.36.210 through 15.36.240.

15.36.210 Variances – Required conditions.

No variance shall be granted unless the applicant for the variance can demonstrate that:

A. An exceptional economic hardship would result without the variance;

B. The relief granted is the minimum necessary;

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

D. No additional public expense will result.

15.36.220 Variances to lower protection levels.

In addition to the requirements of RMC 15.36.210, a variance from the requirements of RMC 15.36.450 through 15.36.510 that would result in a structure not being protected to the elevation of the base flood shall also meet the following requirements:

A. The structure is to be located on a lot one-half acre or less in size contiguous to and surrounded by lots with existing structures constructed below the base flood level;

B. The village board notifies the applicant in writing that the variance will result in increased premium rates for flood insurance up to amounts as high as twenty-five dollars for one hundred dollars of insurance coverage;

C. The village board notifies the applicant in writing that such construction below the base flood level will increase the risks to life and property and that the applicant proceeds with knowledge of these risks; and

D. The village board notifies the applicant that if the variance is issued, it is contingent upon the applicant obtaining approval from other agencies having jurisdiction when the variance violates the requirements of such agencies.

15.36.230 Variances to increase flood heights.

In addition to the requirements of RMC 15.36.210, a variance from the requirements of RMC 15.36.280 or 15.36.290 that would significantly impede or increase the flow and passage of floodwaters shall also meet the following requirements, except that no variance will be granted that would result in an increased flood height greater than nine-tenths foot within the designated regulatory floodway:

A. The resulting increase in the base flood elevation will not affect any existing structures or utilities;

B. The owners of the properties affected by the increased base flood elevation are compensated for the resulting effect on property values and give their written agreement to granting the variance;

C. The resulting increased flood elevations will not affect any flood protection structures.

15.36.240 Variances – Historical structures.

Variances requested in connection with the reconstruction, rehabilitation or restoration of structures listed on the National Register of Historical Places or documented as worthy of preservation by the Illinois Department of Conservation may be granted using criteria more permissive than the requirements of RMC 15.36.210 or 15.36.220.

15.36.250 Nonconforming structures.

Nonconforming structures may remain in use subject to the following regulations:

A. Alterations. A nonconforming structure shall not be enlarged, replaced or structurally altered. A nonconforming structure accidentally damaged may be restored unless the damage exceeds fifty percent of its replacement value, in which case it must thereafter conform to this article. The building inspector shall determine the amount of damage.

B. Building Permit Issued Prior to Adoption or Amendment of the Zoning Ordinance. Proposed structures for which building permits have been issued prior to their designation as nonconforming by adoption or amendment of the zoning ordinance may be completed and used as originally intended subject to the nonconforming provisions of this article.

15.36.260 Nonconforming uses.

Nonconforming uses may be continued subject to the following regulations:

A. Extensions. A nonconforming use shall not be expanded or moved to occupy any portion of the premises, either land or structure, which was not originally occupied by the nonconforming use.

B. Discontinuance. Whenever a nonconforming use of any premises has been discontinued for a period of twelve months, it may not be reestablished.

C. Changes. A nonconforming use shall not be changed to another or different nonconforming use.

15.36.270 Appeals of administrative decisions.

Appeals to the decisions of any administrative body of the village in the interpretation of this article may be made to the village board by any aggrieved person or governmental unit within thirty days of approval or rejection. A further appeal may be made to any decision rendered by the village board within thirty days of approval or rejection before the board of trustees in accordance with existing procedures. Grounds for approval or rejection of all such appeals will be stated in writing.

15.36.280 Floodways identified.

In base flood areas where the floodways have been identified, the following provisions shall prevail:

A. Occupation and Use of Floodways. In floodways which have been identified in RMC 15.36.130 as elements of the floodplains of the base flood, only those uses and structures will be permitted which will not impede or increase the flow and passage of floodwaters. Furthermore, any encroachment in the regulatory floodway which would cause any increase in the base flood level is prohibited. All such uses and structures shall meet applicable zoning requirements for the area.

B. Occupation and Use of Nonfloodway Areas. Development in and use or filling of nonfloodway areas including flood fringes will be permitted if protection is provided against the base flood by proper elevation, compensatory storage and other provisions of this article. No use will be permitted which will adversely affect the capacity of channels, the floodway or drainage facilities or systems. All uses and structures shall meet applicable zoning requirements for the area.

15.36.290 Open storage of floatable materials.

Logs, wastes, lumber, lumber products and other floatable materials or containers shall not be placed, displayed or stored in the floodway and may be stored in flood fringes only upon the issuance of special use permits.

15.36.300 Open storage of other materials.

The open storage or display on a flood fringe of inoperable motor vehicles and similar nonmovable machinery and other nonfloatable materials and products, where permitted by the regulations of the zoning district applicable to such land, shall be considered the same as the placement of fill on the floodplain and shall be subject to the regulations of this article relating to compensatory storage.

15.36.310 Open storage of hazardous materials.

The open storage of materials anywhere in the base flood area which are flammable, explosive, toxic or which could be otherwise injurious to human, animal or plant life is prohibited.

15.36.320 Information required to accompany preliminary subdivision plans.

Accompanying the preliminary plans of each proposed subdivision which involves any portion of a base flood area as described by the official maps of the village, there shall be furnished the following information and data:

A. Contour Map. A topographic map with two-foot interval contours of the land to be subdivided and such adjoining land whose topography may affect the layout or drainage of the subdivision. On such a map, there shall be shown the following:

1. The location of streams and other floodwater runoff channels, their normal channels, the extent of their floodplains at the established high-water elevations, and the limits of the floodway, all properly identified,

2. The normal shoreline of lakes, ponds, swamps and detention basins, their floodplains and lines of inflow and outflow, if any,

3. The location of farm drains and their inlets and outlets,

4. Storm, sanitary and combined sewers and any sewer outfalls,

5. Septic tank systems and outlets, if any,

6. Seeps, springs and flowing and other wells,

7. Location of existing structures that will remain,

8. One-hundred-year flood elevation and limits, including floodway data, for that portion of a subdivision or development which is in the base flood area;

B. Channel Profiles. Profile drawings of each stream channel, pond and basin showing elevations of the following:

1. The streambed,

2. Channel banks, if any,

3. Waterway openings of existing culverts and bridges within and near the tract,

4. Size and elevation of sewer and drain outlets into the stream channel or basin,

5. The base flood elevations established by this article.

15.36.330 Subdivision design generally.

The rules set out in RMC 15.36.340 through 15.36.410 shall govern the design of land improvements with respect to floods.

15.36.340 Subdivisions – Review of proposals within base flood area.

All proposed subdivision and other developments within the base flood area shall be reviewed to assure that the proposed developments are consistent with the need to minimize flood damage, that all public utilities and facilities (such as sewer, gas, electrical and water systems) are located and constructed to minimize or eliminate flood damage and that adequate drainage is provided.

15.36.350 Subdivisions – Layout of streets and other public grounds.

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

15.36.360 Subdivisions – Channel straightening.

Sharply meandering streams or channels may be partially straightened and minor changes made in other channels, subject to the approval of the village engineer, provided:

A. The hydraulic capacity of the floodway is maintained;

B. The volume of floodwater storage outside the floodway is not reduced;

C. Provision is made to stabilize the banks of the modified channel to control erosion; and

D. Any additional permits for this work that are required by the Illinois Department of Transportation and the Corps of Engineers are obtained.

15.36.370 Subdivisions – Lots in base flood area.

Land lying wholly or partially in the base flood area may be laid out and platted as building lots or parcels, provided a building site not lower than the base flood elevation plus one foot: (A) exists on the high part of the lot or parcel, or (B) will be built up during execution of the subdivision improvement plan through general excavation or filling, or (C) can be provided with excavation taken from within the area of the lot or parcel.

15.36.380 Subdivisions – Compensatory storage.

Such filling as may be required or permitted by this article for a building site, or as may otherwise be done in a floodplain, shall be compensated for and balanced by at least an equal volume of excavation taken from below the high water elevation. In the case of streams and channels, such excavation shall be made opposite or immediately adjacent to the areas so filled or occupied and shall be constructed to drain freely and openly to the watercourse.

15.36.390 Subdivisions – Streets and roads.

When failure or interruption of service of streets or roads would endanger public health or safety, streets and roads shall be protected to the base flood elevation. In other instances, protection shall be provided to the extent practical.

15.36.400 Subdivisions – Drainageways.

Whenever the plans call for the passage and/or storage of surface runoff or excess storm water on lots, the grading of all such lots shall be prescribed and established as part of the subdivision plat. The areas so designated for the passage and/or storage of such waters shall not be obstructed. The limits of the high water levels resulting from the passage and/or storage of surface runoff or excess storm water on lots shall be recorded on the plat of record and shall be covered by an easement.

15.36.410 Subdivisions – Manholes.

All sanitary sewer manholes constructed in a floodplain must have a rim elevation of a minimum of one foot above the base flood elevation or be provided with a locking watertight manhole cover.

15.36.420 Water supply and sanitary sewer systems.

The design of water supply and sanitary sewer systems to be located in the floodplain shall minimize or eliminate the discharges from the system into the floodwaters and the infiltration of floodwaters into the system. On-site waste disposal systems shall be located so as to avoid impairment of them or contamination from them during or subsequent to flooding.

15.36.430 Building permits.

Building permits are required for all proposed construction, substantial improvements or other development, including placement of mobile homes, within floodplain areas having special flood hazards. Such permits shall assume that all other necessary permits have been received from those governmental agencies from which approval is required by federal or state law. The building permit applications will be reviewed to assure that any proposed construction is: (1) designed and anchored to prevent flotation, collapse or lateral movement of the structure; (2) constructed with materials and utility equipment resistant to flood damage; and (3) constructed by methods and practices that minimize flood damage. At the time of issuing a building permit, the following information will be noted and recorded by the village:

A. Elevation of the lowest floor, including basement;

B. Where the elevation of the lowest floor is below grade on one or more sides, the elevation of the floor immediately above;

C. Where a structure has been floodproofed, the elevation to which the structure was floodproofed.

15.36.440 Building site.

Each main building or structure that is built on fill shall have or shall be provided with a site, area or yard that is not lower than the established base flood elevation plus one foot and which shall extend beyond the outside walls for a distance of at least five feet. The finished grade or surface of this area beyond the aforesaid five-foot distance shall be graded or surfaced so as to drain away from the walls over a distance of not less than five additional feet.

15.36.450 Building design generally.

The general design criteria set out in RMC 15.36.460 through 15.36.510 shall apply to all new construction and substantial improvements which may be authorized in floodplains.

15.36.460 Building design – Residential structures.

The lowest floor, including the basement, of residential structures must be at an elevation not less than that of the base flood elevation plus one foot, unless they are adequately floodproofed and the village has been granted an exception from the Federal Insurance Administration for placing the lowest floor of the structures at a lower elevation. Within any AO zone, all new construction and substantial improvements of residential structures shall have the lowest floor, including basement, elevated above the crown of the nearest street to or above the depth number specified on the community’s FIRM.

15.36.470 Building design – Nonresidential structures.

The lowest floor, including the basement, of nonresidential structures must be elevated or floodproofed to an elevation not less than that of the base flood elevation plus one foot. Within any AO zone, all new construction and substantial structures shall: (A) have the lowest floor, including basement, elevated above the crown of the nearest street to or above the depth number specified on the FIRM; or (B) together with attendant utility and sanitary facilities shall be completely floodproofed to or above that level to Federal Insurance Administration (FIA) standards.

15.36.480 Building design – Walls.

The walls, foundations and other features which may be authorized for construction or installation at an elevation below that of the base flood elevation plus one foot must be designed to resist appropriate hydrostatic pressures.

15.36.490 Building design – Anchoring.

All authorized structures, including underground and above ground tanks, shall be firmly anchored to prevent flotation. Anchoring materials should be rust resistant.

15.36.500 Building design – Service facilities.

To the maximum extent feasible, all service facilities, such as electrical and heating equipment, shall be installed, constructed or otherwise protected so as to remain operational should floodwaters reach the base flood elevation plus one foot. Water supply and wastewater collection and treatment systems shall be designed and constructed so as to prevent the entrance of floodwaters.

15.36.510 Building design – Floodproofing.

Where the lowest floor elevation, including basement, is below the base flood elevation plus one foot, the structure, with the attendant utility and sanitary facilities, shall be floodproofed to a level of one foot above the base flood elevation. Where floodproofing is required, a registered professional engineer or structural engineer shall certify that the floodproofing methods employed are adequate to withstand the flood depths, pressures, velocities, impact and uplift forces and other factors associated with the base flood, and a record of such certificates indicating the specific elevation to which such structures are floodproofed shall be maintained by the village.

15.36.520 Existing, new and reconstructed mobile home facilities.

Within areas of special flood hazard for new mobile homes, new mobile home parks, and mobile home subdivisions, and for existing mobile home parks where the repair, reconstruction or improvement of streets, utilities and pads equals or exceeds fifty percent of the value of the streets, utilities and pads before the repair, reconstruction or improvement has commenced, the following provisions are required:

A. Ground Anchors. Mobile homes to be placed within areas of special flood hazard shall be anchored to resist flotation, collapse or lateral movement by providing over-the-top and frame ties to ground anchors. Specific requirements shall be that:

1. Over-the-top ties be provided at each of the four corners of the mobile home, with two additional ties per side at intermediate locations and mobile homes less than fifty feet long requiring one additional tie per side;

2. Frame ties be provided at each corner of the home with five additional ties per side at intermediate points and mobile homes less than fifty feet long requiring four additional ties per side;

3. All components of the anchoring system be capable of carrying a force of four thousand eight hundred pounds; and

4. Any additions to the mobile home be similarly anchored.

B. Floor Elevations. Stands or lots shall be elevated on compacted fill or on piers so that the lowest floor of the home will be at an elevation not less than that of the base flood elevation plus one foot.

C. Drainage. Adequate surface drainage and easy access for a hauler shall be provided.

D. Piers. Where piers are used, steps to the home shall be able to be provided and piers shall be placed on stable soil no more than ten feet apart. Steel reinforcement shall be provided for piers more than six feet high.

15.36.530 Administration.

The administration of this article shall be the responsibility of the village board of trustees. Wherever specific provisions of this article fall within the purview of any other commission or agency of the village, responsibility is hereby transferred; provided, that:

A. Variances. No variance shall be issued without the prior concurrence of the village board.

B. Special Use Permit. No special use permit shall be issued without the prior concurrence of the village board.

C. Official Maps and Profiles. Responsibility for all changes to official maps and profiles remains with the village board.

15.36.540 Interpretation.

In the interpretation and application of this article, the provisions expressed herein shall be held to be the minimum requirements and shall be liberally construed in favor of the village and shall not be deemed a limitation or repeal of any other powers granted by state statutes.

15.36.550 Abrogation and greater restrictions.

It is not intended by this article to repeal, abrogate or impair any existing easements, covenants or deed restrictions. However, where this article imposes greater restrictions, the provision of this article shall prevail.

15.36.560 Disclaimer of liability.

The degree of flood protection required by this article is considered reasonable for regulatory purposes and is based on historical records, engineering and scientific methods of study. Larger floods may occur or flood heights may be increased by manmade or natural causes. This article does not imply that areas outside the prescribed floodplain boundaries or land uses permitted within such floodplains will be free from flooding or flood damages. This article shall not create liability on the part of the village or any officer or employee thereof for any flood damage which may result from reliance on this article or on any administrative decision lawfully made thereunder.

15.36.570 Judicial appeals.

Any party shall have the right to appeal decisions of the village before the circuit court of Cook County.

15.36.580 Violation – Penalty.

Violation of the provisions of this article or failure to comply with any of its requirements, including conditions and safeguards established in connection with variances or special use permits, shall constitute a misdemeanor. Any person who violates this article or fails to comply with any of its requirements shall upon conviction thereof be fined not more than five hundred dollars and in addition shall pay all costs and expenses involved in the case. Each day such violation continues shall be considered a separate offense.

15.36.590 Corrective actions.

Nothing contained in this article shall prevent the village from taking such other lawful action as is necessary to prevent or remedy any violation. All such costs in connection therewith shall accrue to the person or persons responsible.

Article II. Construction Within the Floodplain

15.36.700 Issuance of permit.

No permit will be issued for sewer construction within any municipality lying totally or partially within a floodplain unless the municipality shall have adopted a floodplain ordinance which has been filed with and approved by the district as to minimum requirements for the protection of the health and welfare of the public.

15.36.710 Minimum requirements – Generally.

Floodplain ordinances adopted by the municipality shall include the minimum requirements set out in RMC 15.36.720 through 15.36.780.

15.36.720 Minimum elevations and limits.

High water elevations and limits of the floodplain shall be established by the ordinance based on the one-hundred-year flood, as determined by the most recent and best available data listed in RMC 15.36.800. If the one-hundred-year flood information is not available, the regulatory base flood shall be the flood of record. When data of higher order becomes available, data of lower order shall not be used for regulatory purposes.

15.36.730 Building openings.

A door sill, window sill, top of foundation or the bottom of any other opening in the outer walls of a building or structure shall be constructed at an elevation not lower than twelve inches above the established high water elevation of the one-hundred-year flood and not lower than twelve inches above the high water elevation of the flood of record, if the one-hundred-year flood information is not available.

15.36.740 Overhead sewers.

When the building wall encloses open space that is below the base flood elevation, gravity storm and sanitary sewer connections are specifically prohibited and overhead sewers are required for the sanitary connections and sumps for the storm sewer connections.

15.36.750 Connection of existing buildings to sewer system.

Existing buildings to be connected into a proposed sewer system within a floodplain must have sanitary connections designed to protect the sewer system from flooding.

15.36.760 Floodways.

Adequate flood channel provisions should be provided. The width of the floodway should be determined in the field and should be protected from encroachment by the zoning ordinance and by the use of building setbacks. Floodway easements should be provided which permit necessary public channel maintenance and improvement work.

15.36.770 Floodproofing.

That part of the structure constructed within floodplain areas below the high water elevation must be floodproofed. The design must include measures to cope with sewer backup, groundwater seepage and hydrostatic pressure.

15.36.780 Sanitary sewer manholes.

All sanitary sewer manholes constructed in the floodplain must be provided with watertight, lock-type covers, or the rims must be raised to an elevation not lower than twelve inches above the high water elevation.

15.36.790 Conformance with floodplain ordinance.

All projects constructed within a floodplain area shall conform to the requirements of the floodplain ordinance adopted by the local government having jurisdiction over the area in which the project is located. The portion of the project lying within the floodplain shall be delineated and the limits of the floodplain shall be clearly indicated on the overall plans submitted to the district as part of the permit application.

15.36.800 Data to be used for review of sewer permits.

A. In reviewing submittals for sewer permits, the district will base its review on the high water elevations and limits of the one-hundred-year flood as established by the most recent and best available data. If the one-hundred-year flood information is not available, the review will be based on the flood of record data. The data which will be used by the district is listed in this section in descending order of overall accuracy, completeness and currentness. When data of higher order becomes available, data of lower order will not be used.

1. HUD Flood Insurance Studies (FIS), if certified by Illinois Department of Transportation, Division of Water Resources (IDOT-DWR);

2. IDOT-DWR Regulatory Floodplain Maps and Profiles;

3. Soil Conservation Service – Metropolitan Sanitary District of Greater Chicago (SCS-MSDGC) Floodwater Management Plans, using the “without project” data shown therein;

4. Other detailed one-hundred-year flood studies, if certified by IDOT-DWR;

5. HUD Flood Hazard Boundary Maps (FHBM) and Approximate FIS Data;

6. USGS Maps of Flood-Prone Areas;

7. USGS-NIPC Hydrologic Investigation Atlases (Floods of Record).

B. When either the HUD Flood Hazard Boundary Maps or the USGS Maps of Flood-Prone Areas are used to determine the limits of the floodplain, then regulatory high water elevations shall be those of the flood of record.

15.36.810 Construction to meet state requirements.

All construction in the floodplain must meet the requirements of the Rules and Regulations issued by the Illinois Department of Transportation, Division of Water Resources, pursuant to 615 ILCS 5/5 through 5/29a, specifically 5/18f (Rivers, Lakes, and Streams Act), and a permit from the Department must be obtained for such construction.