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A. Permitted Uses: All development within the Floodway Fringe District shall be permitted to the extent that they are not prohibited by any other ordinance (or underlying zoning district) and provided they meet applicable performance standards of the Floodway Fringe District.
B. Performance Standards: All development must be consistent with the need to minimize flood damage and meet the following applicable performance standards. Until a regulatory floodway is designated, no development may increase the base flood elevation more than one foot (1'). The applicant will be responsible for providing the Department of Natural Resources with sufficient technical information to make such determination.
1. All development shall:
a. Be designed and adequately anchored to prevent flotation, collapse or lateral movement.
b. Use construction methods and practices that will minimize flood damage.
c. Use construction materials and utility equipment that are resistant to flood damage.
2. Residential Structures: All new or substantially improved residential structures shall have the lowest floor, including basement, elevated a minimum of one foot (1') above the base flood elevation. Construction shall be upon compacted fill which shall, at all points, be no lower than one foot (1') above the base flood elevation and extend at such elevation at least eighteen feet (18') beyond the limits of any structure erected thereon. Alternate methods of elevating (such as piers or extended foundations) 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. 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 (1') 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 of Iowa 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. All 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 (2) openings, with positioning on at least two (2) walls, having a total net area of not less than one (1) 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 (1') 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.
(4) Such areas shall be used solely for parking of vehicles, building access and low damage potential storage.
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 and other service facilities (including ductwork) elevated to a minimum of one foot (1') above the base flood elevation.
5. Factory-Built Homes:
a. All new and substantially improved 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 (1') above the base flood elevation.
b. All new and substantially improved factory-built homes, including those placed in existing factory-built home parks or subdivisions, shall be anchored to resist flotation, collapse, or lateral movement. Anchorage systems 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 wastewater 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 flood waters into the system as well as the discharge of effluent into flood waters. Wastewater treatment facilities (other than on-site systems) shall be provided with a level of flood protection equal to or greater than one foot (1') above the base flood elevation.
c. New or replacement water supply systems shall be designed to minimize or eliminate infiltration of flood waters 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 (1') 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.
7. Storage of materials and equipment that are flammable, explosive or injurious to human, animal or plant life is prohibited unless elevated a minimum of one foot (1') above the base flood elevation. Other material and equipment must either be similarly elevated or: (i) not be subject to major flood damage and be anchored to prevent movement due to flood waters; or (ii) be readily removable from the area within the time available after flood warning.
8. Flood control structural works such as levees, flood walls, etc. shall provide, at a minimum, protection from the base flood with a minimum of three feet (3') of design freeboard and shall provide for adequate interior drainage. In addition, the Department of Natural Resources shall approve structural flood control works.
9. Watercourse alterations or relocations 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 (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 Section 16-6-4. 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 (5) acres or fifty (50) lots (whichever is less) shall include base flood elevation data for those areas located within the Floodway Fringe (Overlay) 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 six hundred (600) sq. ft. in size. Those portions of the structure located less than one foot (1') above the base flood elevation 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 prevent flotation, collapse, and lateral movement which may result in damage to other structures.
(5) The structure's service facilities such as electrical and heating equipment shall be elevated or floodproofed to at least one foot (1') above the base flood elevation.
(6) The structure's walls shall include openings that satisfy the provisions of Section 16-6-4-7B.4.a. of Title 16 Unified Development Code.
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 Section 16-6-4-7B.5. of Title 16 Unified Development Code 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 one hundred eighty (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 one hundred eighty (180) consecutive days or are not ready for highway use must satisfy requirements of Section 16-6-4-7B.5. of Title 16 Unified Development Code regarding anchoring and elevation of factory-built homes.
13. 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 Development: All new or substantially improved maximum damage potential development shall have the lowest floor (including basement) elevated a minimum of one foot (1') 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 of Iowa 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% annual chance flood; and that the structure, below the 0.2% 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% 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. (Ord. 24-21, 6-21-2021)
A. Permitted Uses:
1. All development within the General Floodplain District shall be permitted to the extent that they are not prohibited by any other ordinance (or underlying zoning district) and provided they meet the applicable performance standards of the General Floodplain District.
2. Any development which involves 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: (i) whether the land involved is either wholly or partly within the floodway or floodway fringe; and (ii) the base flood elevation. The applicant shall be responsible for providing the Department of Natural Resources with sufficient technical information to make the determination.
3. Review by the Iowa Department of Natural Resources is not required for the proposed construction of new or replacement bridges or culverts where:
a. The bridge or culvert is located on a stream that drains less than two (2) square miles; and
b. The bridge or culvert is not associated with a channel modification that constitutes a channel change as specified in 567-71.2(2), Iowa Administrative Code.
B. Performance Standards:
1. All development, 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 16-6-4-6.
2. All development, or portions thereof, to be located in the floodway fringe as determined by the Department of Natural Resources shall meet the applicable provisions and standards of the Floodway Fringe (Overlay) District Section 16-6-4-7. (Ord. 24-21, 6-21-2021)
A. Appointment And Duties Of Board Of Adjustment: A Board of Adjustment is hereby established which shall hear and decide: (i) appeals; and (ii) requests for variances to the provisions of Section 16-6-4, and shall take any other action which is required of the Board.
B. Appeals: Where it is alleged there is any error in any order, requirement, decision, or determination made by an administrative official in the enforcement of Section 16-6-4, the aggrieved party may appeal such action. The notice of appeal shall be filed with the Board of Adjustment and with the official from whom the appeal is taken and shall set forth the specific reason for the appeal. The official from whom the appeal is taken shall transmit to the Board of Adjustment all the documents constituting the record upon which the action appealed from was taken.
C. Variance: The Board of Adjustment may authorize upon request in specific cases such variances from the terms of Section 16-6-4 that will not be contrary to the public interest where, owing to special conditions, a literal enforcement of the provisions of Section 16-6-4 will result in unnecessary hardship. Variances granted must meet the following applicable standards:
1. Variances shall only be granted upon: (i) a showing of good and sufficient cause; (ii) a determination that failure to grant the variance would result in exceptional hardship to the applicant; and (iii) a determination that the granting of the variance will not result in increased flood heights, additional threats to public safety, extraordinary public expense, create nuisances, cause fraud on or victimization of the public or conflict with existing local codes or ordinances.
2. Variances shall not be issued within any designated floodway if any increase in flood levels during the base flood would result. 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.
3. Variances shall only be granted upon a determination that the variance is the minimum necessary, considering the flood hazard, to afford relief.
4. In cases where the variance involves a lower level of flood protection for structures than what is ordinarily required by Section 16-6-4, the applicant shall be notified in writing over the signature of the Administrator that: (i) the issuance of a variance will result in increased premium rates for flood insurance up to amounts as high as twenty-five dollars ($25.00) for one hundred dollars ($100.00) of insurance coverage; and (ii) such construction increases risks to life and property.
5. All variances granted shall have the concurrence or approval of the Department of Natural Resources.
D. Hearings And Decisions Of The Board Of Adjustment:
1. Hearings: Upon the filing with the Board of Adjustment of an appeal or a request for a variance, the Board shall hold a public hearing. The Board shall fix a reasonable time for the hearing and give public notice thereof, as well as due notice to parties in interest. At the hearing, any party may appear in person or by agent or attorney and present written or oral evidence. The Board may require the appellant or applicant to provide such information as is reasonably deemed necessary and may request the technical assistance and/or evaluation of a professional engineer or other expert person or agency, including the Department of Natural Resources.
2. Decisions: 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 Section 16-6-4, 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 Section 16-6-4 and may prescribe such conditions as contained in Section 16-6-4-9B.2.
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 Section 16-6-4 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 flood water 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; and
(13) Such other factors which are relevant to the purpose of Section 16-6-4.
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 Section 16-6-4. 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; and
(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 Section 16-6-4.
(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.
(6) Appeals To The Court: Any person or persons, jointly or severally, aggrieved by any decision of the Board of Adjustment may present to a court of record a petition, duly verified, setting forth that such decision is illegal, in whole or in part, specifying the grounds of the illegality. Such petition shall be presented to the court within thirty (30) days after the filing of the decision in the office of the Board. (Ord. 24-21, 6-21-2021)
1. If such use is discontinued for six (6) consecutive months, any future use of the building premises shall conform to Section 16-6-4.
2. Uses or adjuncts thereof that are or become nuisances shall not be entitled to continue as nonconforming uses.
3. If any nonconforming use or structure is destroyed by any means, including flood, it shall not be reconstructed if the cost is more than fifty percent (50%) of the market value of the structure before the damage occurred, unless it is reconstructed in conformity with the provisions of Section 16-6-4. This limitation does not include the cost of any alteration to comply with existing state or local health, sanitary, building or safety codes or regulations or the cost of any alteration of a structure listed on the National Register of Historic Places, provided that the alteration shall not preclude its continued designation.
B. Except as provided in subsection A.2. of this section, any use which has been permitted as a variance shall be considered a conforming use. (Ord. 24-21, 6-21-2021)
Violations of the provisions of Unified Development Code Section 16-6-4 or failure to comply with any of the requirements (including violations of conditions and safeguards established in connection with grants of variances) shall constitute a misdemeanor. Any person who violates Section 16-6-4 or fails to comply with any of its requirements shall upon conviction thereof be fined not more than five hundred dollars ($500.00) or be imprisoned for not more than thirty (30) days. Each day such violation continues shall be considered a separate offense. Nothing herein contained shall prevent the City of Dubuque from taking such other lawful action as is necessary to prevent or remedy the violation. (Ord. 24-21, 6-21-2021)
The regulations and standards set forth in Unified Development Code Section 16-6-4 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. (Ord. 24-21, 6-21-2021)
A. The OTN is characterized by older building stock and a mix of densely developed commercial and residential structures built on small lots served by alleys. The OTN includes Dubuque's historic downtown core, the Central Avenue and Rhomberg Avenue business corridors, older neighborhood commercial nodes often located on corner lots and a mix of single- and multi-family housing located on separate lots or as upper story apartments.
B. The purpose and intent of the OTN is to conserve the character and integrity of historic building stock in areas of the city where strict application of site design standards for new commercial and multi-family residential development are difficult to apply due to the dense development patterns of these older areas. Often, application of such "suburban style" standards may lead to demolition of existing structures or may limit redevelopment of commercial and multi-family structures or properties in the OTN. (Ord. 52-09, 10-19-2009)
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