1.   Authority. The Legislature of the State has in Chapter 414 of the Code of Iowa, as amended, delegated the power to cities to enact zoning regulations to secure safety from flood and to promote health and the general welfare.

   2.   Findings of Fact.

      A.   The flood hazard areas of the City are subject to periodic inundation which can result in loss of life and 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 of the community.

      B.   These flood losses, hazards, and related adverse effects are caused by:

         (1)   The occupancy of flood hazard areas by uses vulnerable to flood damages which create hazardous conditions as a result of being inadequately elevated or otherwise protected from flooding; and

         (2)   The cumulative effect of obstructions on the floodplain causing increases in flood heights and velocities.

      C.   This chapter relies upon engineering methodology for analyzing flood hazards which is consistent with the standards established by the Department of Natural Resources.

   3.   Statement of Purpose. It is the purpose of this chapter to protect and preserve the rights, privileges and property of the City and its residents and to preserve and improve the peace, safety, health, welfare, and comfort and convenience of its residents by minimizing those flood losses described in Subsection 2(A) of this section with provisions designed to:

      A.   Reserve sufficient floodplain area for the conveyance of flood flows so that flood heights and velocities will not be increased substantially.

      B.   Restrict or prohibit uses which are dangerous to health, safety, or property in times of flood or which cause excessive increases in flood heights or velocities.

      C.   Require that uses vulnerable to floods, including public facilities which serve such uses, be protected against flood damage at the time of initial construction or substantial improvement.

      D.   Protect individuals from buying lands which may not be suited for intended purposes because of flood hazard.

      E.   Assure that eligibility is maintained for property owners in the community to purchase flood insurance through the National Flood Insurance Program.

   1.   Lands to Which Chapter Apply. The provisions of this chapter shall apply to all lands within the jurisdiction of the City shown on the Official Floodplain Zoning Map as being within the boundaries of the Floodway Overlay, Floodway Fringe Overlay, and General Floodplain Overlay Districts, as established in Section 11-5-1 of this title.

   2.   Establishment of Official Floodplain Zoning Map. The Flood Insurance Rate Map (FIRM) for Polk County and Incorporated Areas, City, panels 19153C0165F, 0305F, 0310F, 0326F, 0327F dated February 1, 2019, which were prepared as part of the Flood Insurance Study for Polk County, is (are) hereby adopted by reference and declared to be the Official Floodplain Zoning Map. The flood profiles and all explanatory material contained with the Flood Insurance Study are also declared to be a part of this chapter.

   3.   Rules for Interpretation of District Boundaries. The boundaries of the zoning district areas shall be determined by scaling distances on the Official Floodplain Zoning Map. When an interpretation is needed as to the exact location of a boundary, the Community Development Director shall make the necessary interpretation.

   4.   Interpretation. In their interpretation and application, the provisions of this chapter shall be held to be minimum requirements and shall be liberally construed in favor of the governing body and shall not be deemed a limitation or repeal of any other powers granted by State statutes.

   5.   Warning and Disclaimer of Liability. The standards required by this chapter are considered reasonable for regulatory purposes. This chapter does not imply that areas outside the designated Floodplain District areas will be free from flooding or flood damages. This chapter shall not create liability on the part of the City or any officer or employee thereof for any flood damages that result from reliance on this chapter or any administrative decision lawfully made thereunder.

   6.   Abrogation and Greater Restrictions. It is not intended by this chapter to repeal, abrogate, or impair any existing easements, covenants, or deed restrictions. However, where this chapter imposes greater restrictions, the provisions of this chapter shall prevail. All other ordinances inconsistent with this chapter are hereby repealed to the extent of the inconsistency only.

   7.   Severability. If any section, clause, provision, or portion of this chapter is adjudged unconstitutional or invalid by a court of competent jurisdiction, the remainder of this chapter shall not be affected thereby.

   1.   Appointment, Duties, and Responsibilities of Local Official.

      A.   The Community Development Director is hereby appointed to implement and administer the provisions of this chapter and will herein be referred to as the Administrator.

      B.   Duties and responsibilities of the Administrator shall include, but not necessarily be limited to, the following:

         (1)   Review all floodplain development applications to assure that the provisions of this chapter will be satisfied.

         (2)   Review floodplain development applications to assure that all necessary permits have been obtained from federal, State, and local governmental agencies including approval when required from the Department of Natural Resources for floodplain construction.

         (3)   Record and maintain a record of:

            a.   The elevation (in relation to North American Vertical Datum 1988) of the lowest floor (including basement) of all new or substantially improved structures or

            b.   The elevation to which new or substantially improved structures have been floodproofed.

         (4)   Notify adjacent communities/counties and the Department of Natural Resources prior to any proposed alteration or relocation of a watercourse and submit evidence of such notifications to the Federal Emergency Management Agency.

         (5)   Keep a record of all permits, appeals and such other transactions and correspondence pertaining to the administration of this chapter.

         (6)   Notify the Federal Insurance Administration of any annexations or modifications to the community's boundaries.

         (7)   Review subdivision proposals to insure such proposals are consistent with the purpose of this chapter and advise the Planning and Zoning Commission of potential conflict.

         (8)   Maintain the accuracy of the community's Flood Insurance Rate Maps when;

            a.   Development placed within the Floodway Overlay District results in any of the following:

               i.   An increase in the base flood elevations, or

               ii.   Alteration to the floodway boundary;

            b.   Development placed in Zones A, AE, AH, and A1-30 that does not include a designated floodway that will cause a rise of more than one foot in the base elevation; or

            c.   Development relocates or alters the channel.

         Within six months of the completion of the development, the applicant shall submit to FEMA all scientific and technical data necessary for a Letter of Map Revision.

         (9)   Perform site inspections to ensure compliance with the standards of this chapter.

         (10)   Forward all requests for variances to the Board of Adjustment for consideration.

   2.   Floodplain Development Permit.

      A.   Permit Required. A Floodplain Development Permit issued by the Administrator shall be secured prior to any floodplain development.

      B.   Application for Permit. Application shall be made on forms furnished by the Administrator and shall include the following:

         (1)   Description of the work to be covered by the permit for which application is to be made.

         (2)   Description of the land on which the proposed work is to be done that will readily identify and locate the work to be done.

         (3)   Location and dimensions of all buildings and building additions.

         (4)   Indication of the use or occupancy for which the proposed work is intended.

         (5)   Elevation of the base flood.

         (6)   Elevation of the lowest floor, including the basement, of buildings or of the level to which a building is to be floodproofed.

         (7)   For buildings being improved or rebuilt, the estimated cost of improvements and market value of the building prior to the improvements.

         (8)   Such other information as the Administrator deems reasonably necessary for the purpose of this chapter.

      C.   Action on Permit Application. The Administrator shall, within a reasonable time, make a determination as to whether the proposed floodplain development meets the applicable standards of this chapter and shall approve or disapprove the application. For disapprovals, the applicant shall be informed, in writing, of the specific reasons therefor. The Administrator shall not issue permits for variances except as directed by the Board of Adjustment.

      D.   Construction and Use to be as Provided In Application and Plans. Floodplain Development Permits based on the basis of approved plans and applications authorize only the use, arrangement, and construction set forth in such approved plans and applications and no other use, arrangement, or construction. Any use, arrangement, or construction in conflict with that approved permit shall be deemed a violation of this chapter. The applicant shall be required to submit certification by a professional engineer or land surveyor, as appropriate, registered in the State, that the finished fill, building floor elevations, floodproofing, or other flood protection measures were accomplished in compliance with the provisions of this chapter, prior to the use or occupancy of any structure.

   1.   Permitted Uses. The following uses, having a low flood damage potential and not obstructing flood flow, shall be permitted within the Floodway Overlay District to the extent that they are not prohibited by any other ordinance or statute, and provided they do not require structures, fill, fences, or storage of materials or equipment, excavation, or alteration of a watercourse. In addition, no use shall adversely affect the capacity or flow of Walnut Creek or North Walnut Creek or the channels or floodways of any tributary to Walnut Creek or North Walnut Creek or any other drainage facility or system. All other uses permitted within the underlying zoning district shall be expressly prohibited unless otherwise noted herein.

      A.   Agricultural uses such as, but not limited to, general farming, nurseries, horticulture, truck farming, and sod farming.

      B.   Private and public recreational uses such as, but not limited to: golf courses, archery ranges, parks, picnic grounds, tennis courts, hiking, and biking trails.

      C.   Parks and public recreational uses, and structures accessory to such uses, by the City.

      D.   Such other open space uses similar in nature to the above uses, as determined by the Community Development Director.

      E.   Utility transmission lines, including poles and towers.

   2.   Performance Standards. All Floodway Overlay District uses allowed as a permitted use shall meet the following standards:

      A.   No use shall be permitted in the Floodway Overlay District that would result in any increase in the base flood elevation. Consideration of the effects of any development on flood levels shall be based upon the assumption that an equal degree of development would be allowed for similarly situated lands.

      B.   All uses within the Floodway Overlay District shall:

         (1)   Be consistent with the need to minimize flood damage.

         (2)   Use construction methods and practices that will minimize flood damage.

         (3)   Use construction materials and utility equipment that are resistant to flood damage.

      C.   No use shall affect the capacity or conveyance of the channel or floodway of any tributary to the mainstream, drainage ditch, or any other drainage facility or system.

      D.   Structures, buildings, and sanitary and utility systems, if permitted, shall meet the applicable performance standards of the Floodway Fringe Overlay District, and shall be constructed or aligned to present the minimum possible resistance to flood flows.

      E.   Buildings, if permitted, shall have a low flood damage potential and shall not be for human habitation.

      F.   Storage of materials or equipment that are buoyant, flammable, explosive or injurious to human, animal or plant life is prohibited. Storage of other material may be allowed if readily removable from the Floodway Overlay District within the time available after flood warning.

      G.   Watercourse alterations or relocations (channel changes and modifications) must be designed to maintain the flood carrying capacity within the altered or relocated portion. In addition, such alterations or relocations must be approved by the Department of Natural Resources.

      H.   Any fill allowed in the floodway must be shown to have some beneficial purpose and shall be limited to the minimum amount necessary.

      I.   Pipeline river or stream crossings shall be buried in the streambed and banks or otherwise sufficiently protected to prevent rupture due to channel degradation and meandering or due to the action of flood flows.

   1.   Permitted Uses. All uses within the Floodway Fringe Overlay District shall be permitted to the extent that they are not prohibited by any other chapter (or underlying zoning district) and provided they meet applicable performance standards of the Floodway Fringe Overlay District.

   2.   Performance Standards. All uses must be consistent with the need to minimize flood damage and meet the following applicable performance standards. Where base flood data has not been provided on the Flood Insurance Rate Map, the Iowa Department of Natural Resources shall be contacted to compute such data. The applicant will be responsible for providing the Department of Natural Resources with sufficient technical information to make such determination.

      A.   All Structures. All structures shall:

         (1)   Be adequately anchored to prevent flotation, collapse, or lateral movement of the structure.

         (2)   Use construction methods and practices that will minimize flood damage.

         (3)   Use construction materials and utility equipment that are resistant to flood damage.

      B.   Residential Structures.

         (1)   Residential Structures without Basements. All new or substantially improved residential structures shall have the lowest floor elevated a minimum of one foot above the base flood elevation. Construction shall be upon compacted fill which shall, at all points, be no lower than one foot above the base flood elevation and extend at such elevation at least 18 feet beyond the limits of any structure erected thereon. Subject to approval by the Administrator, alternate methods of elevating may be allowed where existing topography, street grades, or other factors preclude elevating by fill. In such cases, the methods used must be adequate to support the structure as well as withstand the various forces and hazards associated with flooding.

         (2)   Residential Structures with Basements.

            a.   All new or substantially improved residential structures with basements shall have the basement, together with attendant utility and sanitation systems, floodproofed to a level at least one foot above the base flood elevation. Construction of floodproofed basements shall:

               i.   Take place within a compacted fill berm which shall, at all points, be no lower than one foot above the base flood elevation and extend at such elevation at least 18 feet beyond the limits of any structure erected thereon;

               ii.   Be constructed such that the lowest part of all basement external openings, such as doors and windows, are placed at least one foot above the base flood elevation;

               iii.   Be designed and constructed so that the structure, below one foot above the base flood elevation, is watertight with walls substantially impermeable to the passage of water, and with the capability to resist hydrostatic and hydrodynamic loads and the effects of buoyancy associated with the base flood; and

               iv.   Be designed so that minimal structural damage will occur if this design is exceeded.

            b.   A professional engineer registered in the State shall certify that the floodproofed basement has been designed in accordance with the above provisions. A record of the certification indicating the specific elevation (in relation to North American Vertical Datum 1988) to which any structures are floodproofed shall be maintained by the Community Development Director. All basements constructed in accordance with these provisions shall not be used for sleeping purposes and shall require the approval and recording of an agreement that indicates the restriction.

            c.   All new residential structures located in areas that would become isolated due to flooding of surrounding ground shall be provided with a means of access that will be passable by wheeled vehicles during the base flood. However, this criterion shall not apply where the Administrator determines there is sufficient flood warning time for the protection of life and property. When estimating flood warning time, consideration shall be given to the criteria listed in 567-75.2(3), Iowa Administrative Code.

   3.   Non-Residential Structures. All new or substantially improved non-residential structures shall have the lowest floor (including basement) elevated a minimum of one foot above the base flood elevation, or together with attendant utility and sanitary systems, be floodproofed to such a level. When floodproofing is utilized, a professional engineer registered in the State shall certify that the floodproofing methods used are adequate to withstand the flood depths, pressures, velocities, impact, and uplift forces and other factors associated with the base flood; and that the structure, below the base flood elevation is watertight with walls substantially impermeable to the passage of water. A record of the certification indicating the specific elevation (in relation to North American Vertical Datum 1988) to which any structures are floodproofed shall be maintained by the Administrator.

   4.   New and Substantially Improved Structures.

      A.   Fully enclosed areas below the “lowest floor” (not including basements) that are subject to flooding shall be designed to automatically equalize hydrostatic flood forces on exterior walls by allowing for the entry and exit of floodwaters. Designs for meeting this requirement must either be certified by a registered professional engineer or meet or exceed the following minimum criteria:

         (1)   A minimum of two openings, with positioning on at least two walls, having a total net area of not less than one square inch for every square foot of enclosed area subject to flooding shall be provided.

         (2)   The bottom of all openings shall be no higher than one foot above grade.

         (3)   Openings may be equipped with screens, louvers, valves, or other coverings or devices provided they permit the automatic entry and exit of floodwaters.

Where the distance between the floor and ceiling of the fully enclosed area below the “lowest floor” is five feet or more, the applicant shall be required to sign and record with the County Recorder a Non-Conversion Agreement that ensures the lower enclosed area remains compliant with the criteria outlined in this subsection.

      B.   New and substantially improved structures must be designed (or modified) and adequately anchored to prevent flotation, collapse, or lateral movement of the structure resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy.

      C.   New and substantially improved structures shall be constructed with electrical, heating, ventilation, plumbing, air conditioning equipment, duct work, and other service facilities elevated or floodproofed to a minimum of one foot above the base flood elevation.

   5.   Factory-Built Homes.

      A.   All factory-built homes, including those placed in existing factory-built home parks or subdivisions, shall be elevated on a permanent foundation such that the lowest floor of the structure is a minimum of one foot above the base flood elevation.

      B.   All factory-built homes, including those placed in existing factory-built home parks or subdivisions, shall be anchored to resist flotation, collapse, or lateral movement. Methods of anchoring may include, but are not limited to, use of over-the-top or frame ties to ground anchors as required by the State Building Code.

   6.   Utility and Sanitary Systems:

      A.   On-site waste disposal and water supply systems shall be located or designed to avoid impairment to the system or contamination from the system during flooding.

      B.   All new and replacement sanitary sewage systems shall be designed to minimize or eliminate infiltration of floodwaters into the system as well as the discharge of effluent into floodwaters. Wastewater treatment facilities (other than on-site systems) shall be provided with a level of flood protection equal to or greater than one foot above the base flood elevation.

      C.   New or replacement water supply systems shall be designed to minimize or eliminate infiltration of floodwaters into the system. Water supply treatment facilities (other than on-site systems) shall be provided with a level of protection equal to or greater than one foot above the base flood elevation.

      D.   Utilities such as gas or electrical systems shall be located and constructed to minimize or eliminate flood damage to the system and the risk associated with such flood damaged or impaired systems.

      E.   The utilization of septic sanitary sewer systems shall be prohibited within the Floodway Fringe Overlay District.

   7.   Hazardous Material. Storage of materials and equipment that are flammable, explosive, or injurious to human, animal, or plant life is prohibited unless elevated or protected to a minimum of one foot above the 500-year flood elevation.

   8.   Flood Control Structures. Structural works such as levees, flood walls, etc., shall provide, at a minimum, protection from the base flood with a minimum of three feet of design freeboard and shall provide for adequate interior drainage. In addition, the Department of Natural Resources shall approve structural flood control works.

   9.   Changes in Watercourse. Alterations or relocations to the watercourse must be designed to maintain the flood carrying capacity within the altered or relocated portion. In addition, the Department of Natural Resources must approve such alterations or relocations.

   10.   Subdivisions. Subdivisions (including factory-built home parks and subdivisions) shall be consistent with the need to minimize flood damages and shall have adequate drainage provided to reduce exposure to flood damage. Development associated with subdivision proposals (including the installation of public utilities) shall meet the applicable performance standards of this chapter. Subdivision proposals intended for residential use shall provide all lots with a means of access which will be passable by wheeled vehicles during the base flood. Proposals for subdivisions greater than five acres or 50 lots (whichever is less) shall include base flood elevation data for those areas located within the Floodplain District.

   11.   Accessory Structures to Residential Uses.

      A.   Detached garages, sheds, and similar structures that are incidental to a residential use are exempt from the base flood elevation requirements where the following criteria are satisfied.

         (1)   The structure shall be designed to have low flood damage potential. Its size shall not exceed 600 square feet in size. Those portions of the structure located less than one foot above the BFE must be constructed of flood- resistant materials.

         (2)   The structure shall be used solely for low flood damage potential purposes such as vehicle parking and limited storage. The structure shall not be used for human habitation.

         (3)   The structure shall be constructed and placed on the building site so as to offer minimum resistance to the flow of floodwaters.

         (4)   The structure shall be firmly anchored to resist flotation, collapse, and lateral movement.

         (5)   The structure’s service facilities such as electrical and heating equipment shall be elevated or floodproofed to at least one foot above the base flood elevation.

         (6)   The structure’s walls shall include openings that satisfy the provisions of Subsection 4(A) of this section.

      B.   Exemption from the base flood elevation requirements for such a structure may result in increased premium rates for flood insurance coverage of the structure and its contents.

   12.   Recreational Vehicles.

      A.   Recreational vehicles are exempt from the requirements of Subsection 5 of this section regarding anchoring and elevation of factory-built homes when the following criteria are satisfied.

         (1)   The recreational vehicle shall be located on the site for less than 180 consecutive days, and,

         (2)   The recreational vehicle must be fully licensed and ready for highway use. A recreational vehicle is ready for highway use if it is on its wheels or jacking system and is attached to the site only by quick disconnect type utilities and security devices and has no permanently attached additions.

      B.   Recreational vehicles that are located on the site for more than 180 consecutive days or are not ready for highway use must satisfy the requirements of Subsection 5 of this section regarding anchoring and elevation of factory-built homes.

   13.   River and Stream Crossings. Pipeline river and stream crossings shall be buried in the streambed and banks, or otherwise sufficiently protected to prevent rupture due to channel degradation and meandering.

   14.   Maximum Damage Potential Uses. All new or substantially improved maximum damage potential uses shall have the lowest floor (including basement) elevated a minimum of one foot above the elevation of the 500-year flood, or together with attendant utility and sanitary systems, be floodproofed to such a level. When floodproofing is utilized, a professional engineer registered in the State shall certify that the floodproofing methods used are adequate to withstand the flood depths, pressures, velocities, impact, and uplift forces and other factors associated with the 0.2 percent annual chance flood; and that the structure, below the 0.2 percent annual chance flood elevation is watertight with walls substantially impermeable to the passage of water. A record of the certification indicating the specific elevation (in relation to North American Vertical Datum 1988) to which any structures are floodproofed shall be maintained by the Administrator. Where 0.2 percent chance flood elevation data has not been provided in the Flood Insurance Study, the Iowa Department of Natural Resources shall be contacted to compute such data. The applicant will be responsible for providing the Department of Natural Resources with sufficient technical information to make such determinations.

   15.   Outdoor Storage. The storage of goods, materials, equipment, or any other products outside of an approved structure shall be prohibited within the Floodway Fringe Overlay District.

   1.   Permitted Uses.

      A.   All uses within the General Floodplain Overlay District shall be permitted to the extent that they are not prohibited by any other chapter (or underlying zoning district) and provided they meet the applicable performance standards of the General Floodplain Overlay District.

      B.   Any uses which involve placement of structures, factory-built homes, fill or other obstructions, storage of materials or equipment, excavation or alteration of a watercourse shall be reviewed by the Department of Natural Resources to determine:

         (1)   Whether the land involved is either wholly or partly within the Floodway Overlay or Floodway Fringe Overlay; and

         (2)   The base flood elevation. The applicant shall be responsible for providing the Department of Natural Resources with sufficient technical information to make the determination.

      C.   Review by the Iowa Department of Natural Resources is not required for the proposed construction of new or replacement bridges or culverts where:

         (1)   The bridge or culvert is located on a stream that drains less than 100 square miles, and

         (2)   The bridge or culvert is not associated with a channel modification that constitutes a channel change as specified in 567-71.2(1)b, Iowa Administrative Code.

   2.   Performance Standards.

      A.   All uses, or portions thereof, to be located in the floodway as determined by the Department of Natural Resources shall meet the applicable provisions and standards of the Floodway Overlay District,Section 11-11-4 of this chapter.

      B.   All uses, or portions thereof, to be located in the Floodway Fringe Overlay as determined by the Department of Natural Resources shall meet the applicable provisions and standards of the Floodway Fringe Overlay District,Section 11-11-5 of this chapter.

   1.   Decisions of the Board of Adjustment. The Board shall arrive at a decision on an appeal or variance within a reasonable time. In passing upon an appeal, the Board may, so long as such action is in conformity with the provisions of this chapter, reverse or affirm, wholly or in part, or modify the order, requirement, decision, or determination appealed from, and it shall make its decision, in writing, setting forth the findings of fact and the reasons for its decision. In granting a variance, the Board shall consider such factors as contained in this section and all other relevant sections of this chapter and may prescribe such conditions as contained in Subsection (1)(B) of this section.

      A.   Factors Upon which the Decision of the Board of Adjustment Shall be Based. In passing upon applications for variances, the Board shall consider all relevant factors specified in other sections of this chapter and:

         (1)   The danger to life and property due to increased flood heights or velocities caused by encroachments.

         (2)   The danger that materials may be swept on to other land or downstream to the injury of others.

         (3)   The proposed water supply and sanitation systems and the ability of these systems to prevent disease, contamination, and unsanitary conditions.

         (4)   The susceptibility of the proposed facility and its contents to flood damage and the effect of such damage on the individual owner.

         (5)   The importance of the services provided by the proposed facility to the City.

         (6)   The requirements of the facility for a floodplain location.

         (7)   The availability of alternative locations not subject to flooding for the proposed use.

         (8)   The compatibility of the proposed use with existing development and development anticipated in the foreseeable future.

         (9)   The relationship of the proposed use to the Comprehensive Plan and floodplain management program for the area.

         (10)   The safety of access to the property in times of flood for ordinary and emergency vehicles.

         (11)   The expected heights, velocity, duration, rate of rise, and sediment transport of the floodwater expected at the site.

         (12)   The cost of providing governmental services during and after flood conditions, including maintenance and repair of public utilities (sewer, gas, electrical, and water systems), facilities, streets, and bridges.

         (13)   Such other factors which are relevant to the purpose of this chapter.

      B.   Conditions Attached to Variances. Upon consideration of the factors listed above, the Board of Adjustment may attach such conditions to the granting of variances as it deems necessary to further the purpose of this chapter. Such conditions may include, but not necessarily be limited to:

         (1)   Modification of waste disposal and water supply facilities.

         (2)   Limitation of periods of use and operation.

         (3)   Imposition of operational controls, sureties, and deed restrictions.

         (4)   Requirements for construction of channel modifications, dikes, levees, and other protective measures, provided such are approved by the Department of Natural Resources and are deemed the only practical alternative to achieving the purpose of this chapter.

         (5)   Floodproofing measures shall be designed consistent with the flood protection elevation for the particular area, flood velocities, duration, rate of rise, hydrostatic and hydrodynamic forces, and other factors associated with the regulatory flood. The Board of Adjustment shall require that the applicant submit a plan or document certified by a registered professional engineer that the floodproofing measures are consistent with the regulatory flood protection elevation and associated flood factors for the particular area. Such floodproofing measures may include, but are not limited to, the following:

            a.   Anchorage to resist flotation and lateral movement.

            b.   Installation of watertight doors, bulkheads, shutters, or similar methods of construction.

            c.   Reinforcement of walls to resist water pressures.

            d.   Use of paints, membranes, or mortars to reduce the seepage of water through walls.

            e.   Addition of mass or weight structures to resist flotation.

            f.   Installation of pumps to lower water levels in structures.

            g.   Pumping facilities or comparable practices for subsurface drainage systems for buildings to relieve external foundation wall and basement flood pressures.

            h.   Construction of water supply and waste treatment systems so as to prevent the entrance of floodwaters.

            i.   Construction to resist rupture or collapse caused by water pressure or floating debris.

            j.   Installation of valves or controls on sanitary and storm drains which will permit the drains to be closed to prevent backup of sewage and stormwater into buildings or structures.

            k.   Location of all electrical equipment, including circuits and installed electrical appliances, in a manner that will assure they are not subject to flooding.

   2.   Variances. No variance shall be granted for any development within the Floodway Overlay District that would result in any increase in floods during the occurrence of the base flood. Consideration of the effects of any development on flood levels shall be based upon the assumption that an equal degree of development would be allowed for similarly situated lands. All variances granted affecting the Floodway Overlay or Floodway Fringe Overlay Districts shall have approval of the Iowa Department of Natural Resources.

   The regulations and standards set forth in this chapter may, from time to time be amended, supplemented, changed, or repealed. No amendment, supplement, change, or modification shall be undertaken without prior approval of the Department of Natural Resources.