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Unless specifically defined below, words or phrases used in this chapter shall be interpreted to give them the meaning they have in common usage and to give this chapter its most reasonable application.
APPEAL BOARD: The planning and zoning commission of the City of Mitchell.
AREA OF FUTURE CONDITIONS FLOOD HAZARD: The land area that would be inundated by the one percent (1%) annual chance (100-year) flood based on future conditions hydrology.
AREA OF SHALLOW FLOODING: A designated AO, AH, AR/AO, AR/AH, or VO zone on a community's flood insurance rate map (FIRM) with a one percent (1%) or greater annual chance of flooding to an average depth of one to three feet (3') where a clearly defined channel does not exist, where the path of flooding is unpredictable, and where velocity flow may be evident. Such flooding is characterized by ponding or sheet flow.
AREA OF SPECIAL FLOOD HAZARD: The land in the floodplain within a community subject to a one percent (1%) or greater chance of flooding in any given year. The area may be designated as zone A on the FHBM. After detailed ratemaking has been completed in preparation for publication of the flood insurance rate map, zone A usually is refined into zones A, AO, AH, A1-30, AE, A99, AR, AR/A1-30, AR/AE, AR/AO, AR/AH, AR/A, VO, or V1-30, VE, or V. For purposes of these regulations, the term "special flood hazard area" is synonymous in meaning with the phrase "area of special flood hazard".
AREA OF SPECIAL FLOOD RELATED EROSION HAZARD: The land within a community which is most likely to be subject to severe flood related erosion losses. The area may be designated as zone E on the flood hazard boundary map (FHBM). After the detailed evaluation of the special flood related erosion hazard area; in preparation for publication of the FIRM, zone E may be further refined.
BASE FLOOD: The flood having a one percent (1%) chance of being equaled or exceeded in any given year.
BASE FLOOD ELEVATION (BFE): The water surface elevation of the one percent (1%) annual chance flood. The height in relation to mean sea level expected to be reached by the waters of the base flood at pertinent points in the floodplains of coastal and riverine areas.
BASEMENT: Any area of the building having its floor subgrade (below ground level) on all sides.
BREAKAWAY WALL: A wall that is not part of the structural support of the building and is intended through its design and construction to collapse under specific lateral loading forces, without causing damage to the elevated portion of the building or supporting foundation system.
BUILDING: See definition of Structure.
CONDITIONAL LETTER OF MAP REVISION (CLOMR): A statement from FEMA that if a project is constructed as planned, a letter of map revision can be issued later.
DEVELOPMENT: Any manmade change to improved or unimproved real estate, including, but not limited to, buildings or other structures, mining, dredging, filling, grading, paving, excavation or drilling operations or storage of equipment or materials.
EROSION: The process of the gradual wearing away of land masses. This peril is not per se covered under the program.
EXISTING CONSTRUCTION: For the purposes of determining rates, structures for which the "start of construction" commenced before the effective date of the FIRM or before January 1, 1975, for FIRMs effective before that date. "Existing construction" may also be referred to as "existing structures".
EXISTING MANUFACTURED HOME PARK OR SUBDIVISION: A manufactured home park or subdivision for which the construction of facilities for servicing the lots on which the manufactured homes are to be affixed (including, at a minimum, the installation of utilities, the construction of streets, and either final site grading or the pouring of concrete pads) is completed before the effective date of the floodplain management regulations adopted by a community.
EXISTING STRUCTURES: See definition of Existing Construction.
EXPANSION TO AN EXISTING MANUFACTURED HOME PARK OR SUBDIVISION: The preparation of additional sites by the construction of facilities for servicing the lots on which the manufactured homes are to be affixed (including the installation of utilities, the construction of streets, and either final site grading or the pouring of concrete pads).
FLOOD ELEVATION DETERMINATION: A determination by the administrator of the water surface elevations of the base flood, that is, the flood level that has a one percent (1%) or greater chance of occurrence in any given year.
FLOOD INSURANCE RATE MAP (FIRM): An official map of a community, on which the administrator has delineated both the special hazard areas and the risk premium zones applicable to the community.
FLOOD INSURANCE STUDY OR FLOOD ELEVATION STUDY: An examination, evaluation and determination of flood hazards and, if appropriate, corresponding water surface elevations, or an examination, evaluation and determination of mudslide (i.e., mudflow) and/or flood related erosion hazards.
FLOOD OR FLOODING:
A. A general and temporary condition of partial or complete inundation of normally dry land areas from:
1. The overflow of inland or tidal waters.
2. The unusual and rapid accumulation or runoff of surface waters from any source.
3. Mudslides (i.e., mudflows) which are proximately caused by flooding as defined in subsection A1 of this definition and are akin to a river of liquid and flowing mud on the surfaces of normally dry land areas, as when earth is carried by a current of water and deposited along the path of the current.
B. The collapse or subsidence of land along the shore of a lake or other body of water as a result of erosion or undermining caused by waves or currents of water exceeding anticipated cyclical levels or suddenly caused by an unusually high water level in a natural body of water, accompanied by a severe storm, or by an unanticipated force of nature, such as flash flood or an abnormal tidal surge, or by some similarly unusual and unforeseeable event which results in flooding as defined in subsection A1 of this definition.
FLOODPLAIN OR FLOOD PRONE AREA: Any land area susceptible to being inundated by water from any source (see definition of Flood Or Flooding).
FLOODPROOFING: Any combination of structural and nonstructural additions, changes, or adjustments to structures which reduce or eliminate flood damage to real estate or improved real property, water and sanitary facilities, structures and their contents.
FLOODWAY: See definition of Regulatory Floodway.
FLOODWAY ENCROACHMENT LINES: The lines marking the limits of floodways on federal, state and local floodplain maps.
FREEBOARD: A factor of safety usually expressed in feet above a flood level for purposes of floodplain management. "Freeboard" tends to compensate for the many unknown factors that could contribute to flood heights greater than the height calculated for a selected size flood and floodway conditions, such as wave action, bridge openings, and the hydrological effect of urbanization of the watershed.
FUNCTIONALLY DEPENDENT USE: A use which cannot perform its intended purpose unless it is located or carried out in close proximity to water. The term includes only docking facilities, port facilities that are necessary for the loading and unloading of cargo or passengers, and ship building and ship repair facilities, but does not include long term storage or related manufacturing facilities.
HIGHEST ADJACENT GRADE: The highest natural elevation of the ground surface prior to construction next to the proposed walls of a structure.
HISTORIC STRUCTURE: Any structure that is:
A. Listed individually in the national register of historic places (a listing maintained by the department of interior) or preliminarily determined by the secretary of the interior as meeting the requirements for individual listing on the national register;
B. Certified or preliminarily determined by the secretary of the interior as contributing to the historical significance of a registered historic district or a district preliminarily determined by the secretary to qualify as a registered historic district;
C. Individually listed on a state inventory of historic places in states with historic preservation programs which have been approved by the secretary of the interior; or
D. Individually listed on a local inventory of historic places in communities with historic preservation programs that have been certified either:
1. By an approved state program as determined by the secretary of the interior or
2. Directly by the secretary of the interior in states without approved programs.
LETTER OF MAP REVISION (LOMR): An official revision to a FEMA map done by describing the property affected.
LETTER OF MAP REVISION BASED ON FILL (LOMR-F): An official revision to a FEMA map done by describing the property affected with new fill.
LEVEE: A manmade structure usually an earthen embankment, designed and constructed in accordance with sound engineering practices to contain, control, or divert the flow of water so as to provide protection from temporary flooding.
LEVEE SYSTEM: A flood protection system which consists of a levee, or levees, and associated structures, such as closure and drainage devices, which are constructed and operated in accordance with sound engineering practices.
LOWEST FLOOR: The lowest floor of the lowest enclosed area (including basement). An unfinished or flood resistant enclosure, usable solely for parking of vehicles, building access or storage in an area other than a basement area is not considered a building's lowest floor; provided, that such enclosure is not built so as to render the structure in violation of the applicable nonelevation design requirements of CFR section 60.3.
MANUFACTURED HOME: A structure, transportable in one or more sections, which is built on a permanent chassis and is designed for use with or without a permanent foundation when attached to the required utilities. The term "manufactured home" does not include a "recreational vehicle".
MANUFACTURED HOME PARK OR SUBDIVISION: A parcel (or contiguous parcels) of land divided into two (2) or more manufactured home lots for rent or sale.
MAP: The flood hazard boundary map (FHBM) or the flood insurance rate map (FIRM) for a community issued by the agency.
MEAN SEA LEVEL: For purposes of the national flood insurance program, the national geodetic vertical datum (NGVD) of 1929 or other datum, to which base flood elevations shown on a community's flood insurance rate map are referenced.
NEW CONSTRUCTION: For the purposes of determining insurance rates, structures for which the "start of construction" commenced on or after the effective date of an initial FIRM or after December 31, 1974, whichever is later, and includes any subsequent improvements to such structures. For floodplain management purposes, new construction means structures for which the start of construction commenced on or after the effective date of a floodplain management regulation adopted by a community and includes any subsequent improvements to such structures.
NEW MANUFACTURED HOME PARK OR SUBDIVISION: A manufactured home park or subdivision for which the construction of facilities for servicing the lots on which the manufactured homes are to be affixed (including at a minimum, the installation of utilities, the construction of streets, and either final site grading or the pouring of concrete pads) is completed on or after the effective date of floodplain management regulations adopted by a community.
RECREATIONAL VEHICLE: A vehicle which is:
A. Built on a single chassis;
B. Four hundred (400) square feet or less when measured at the largest horizontal projection;
C. Designed to be self-propelled or permanently towable by a light duty truck; and
D. Designed primarily not for use as a permanent dwelling but as temporary living quarters for recreational, camping, travel, or seasonal use.
REGULATORY FLOODWAY: The channel of a river or other watercourse and the adjacent land areas that must be reserved in order to discharge the base flood without cumulatively increasing the water surface elevation more than a designated height.
SPECIAL FLOOD HAZARD AREA: See definition of Area Of Special Flood Hazard.
SPECIAL HAZARD AREA: An area having special flood, mudslide (i.e., mudflow), or flood related erosion hazards, and shown on an FHBM or FIRM as zone A, AO, A1-30, AE, AR, AR/A1-30, AR/AE, AR/AO, AR/AH, AR/A, A99, AH, VO, V1-30, VE, V, M, or E.
START OF CONSTRUCTION (For Other Than New Construction Or Substantial Improvements Under The Coastal Barrier Resources Act (Pub. L. 97-348)): Includes substantial improvement, and means the date the building permit was issued, provided the actual start of construction, repair, reconstruction, rehabilitation, addition placement, or other improvement was within one hundred eighty (180) days of the permit date. The actual start means either the first placement of permanent construction of a structure on a site, such as the pouring of slab or footings, the installation of piles, the construction of columns, or any work beyond the stage of excavation; or the placement of a manufactured home on a foundation. Permanent construction does not include land preparation, such as clearing, grading and filling; nor does it include the installation of streets and/or walkways; nor does it include excavation for a basement, footings, piers, or foundations or the erection of temporary forms; nor does it include the installation on the property of accessory buildings, such as garages or sheds not occupied as dwelling units or not part of the main structure. For a substantial improvement, the actual start of construction means the first alteration of any wall, ceiling, floor, or other structural part of a building, whether or not that alteration affects the external dimensions of the building.
STRUCTURE: For floodplain management purposes, a walled and roofed building, including a gas or liquid storage tank, that is principally aboveground, as well as a manufactured home. Structure, for insurance purposes, means:
A. A building with two (2) or more outside rigid walls and a fully secured roof, that is affixed to a permanent site;
B. A manufactured home ("a manufactured home", also known as a mobile home, is a structure: built on a permanent chassis, transported to its site in one or more sections, and affixed to a permanent foundation); or
C. A travel trailer without wheels built on a chassis and affixed to a permanent foundation, that is regulated under the community's floodplain management and building ordinances or laws.
For the latter purpose, "structure" does not mean a recreational vehicle or a park trailer or other similar vehicle, except as described in subsection C of this definition, or a gas or liquid storage tank.
SUBSTANTIAL DAMAGE: Damage of any origin sustained by a structure whereby the cost of restoring the structure to its before damaged condition would equal or exceed fifty percent (50%) of the market value of the structure before the damage occurred.
SUBSTANTIAL IMPROVEMENT: Any reconstruction, rehabilitation, addition, or other improvement of a structure, the cost of which equals or exceeds fifty percent (50%) of the market value of the structure before the "start of construction" of the improvement. This term includes structures which have incurred "substantial damage", regardless of the actual repair work performed. The term does not, however, include either:
A. Any project for improvement of a structure to correct existing violations of state or local health, sanitary, or safety code specifications which have been identified by the local code enforcement official and which are the minimum necessary to assure safe living conditions or
B. Any alteration of a "historic structure", provided that the alteration will not preclude the structure's continued designation as a "historic structure".
VARIANCE: A grant of relief by a community from the terms of a floodplain management regulation.
VIOLATION: The failure of a structure or other development to be fully compliant with the community's floodplain management regulations. A structure or other development without the elevation certificate, other certifications, or other evidence of compliance required in CFR sections 60.3(b)(5), (c)(4), (c)(10), (d)(3), (e)(2), (e)(4), or (e)(5) is presumed to be in violation until such time as that documentation is provided.
WATER SURFACE ELEVATION: The height, in relation to the national geodetic vertical datum (NGVD) of 1929 (or other datum, where specified), of floods of various magnitudes and frequencies in the floodplains of coastal or riverine areas. (Ord. 2342, 9-20-2010; amd. Ord. O2019-14, 8-19-2019)
A. Lands To Which This Chapter Applies: This chapter shall apply to all areas of special flood hazard within the city of Mitchell and extraterritorial zoning jurisdiction.
B. Basis For Establishing The Areas Of Special Flood Hazard: The areas of special flood hazard identified by the federal emergency management agency in a scientific and engineering report entitled, "The Flood Insurance Study For The City Of Mitchell", dated September 29, 2010, with accompanying flood insurance rate maps (FIRM), dated September 29, 2010, and any revisions thereto are hereby adopted by reference and declared to be a part of this chapter.
C. Establishment Of Development Permit: A development permit shall be required to ensure conformance with the provisions of this chapter.
D. Compliance: No structure or land shall hereafter be located, altered, or have its use changed without full compliance with the terms of this chapter and other applicable regulations.
E. Abrogation And Greater Restrictions: This chapter is not intended to repeal, abrogate, or impair any existing easements, covenants, or deed restrictions. However, where this chapter and another ordinance, easement, covenant, or deed restriction conflict or overlap, whichever imposes the more stringent restrictions shall prevail.
F. Interpretation: In the interpretation and application of this chapter, all provisions shall be:
1. Considered as minimum requirements;
2. Liberally construed in favor of the governing body; and
3. Deemed neither to limit nor repeal any other powers granted under state statutes.
G. Warning And Disclaimer Or Liability: The degree of flood protection required by this chapter is considered reasonable for regulatory purposes and is based on scientific and engineering considerations. On rare occasions greater floods can and will occur and flood heights may be increased by manmade or natural causes.
This chapter does not imply that land outside the areas of special flood hazards or uses permitted within such areas will be free from flooding or flood damages. This chapter shall not create liability on the part of the community or any official or employee thereof for any flood damages that result from reliance on this chapter or any administrative decision lawfully made thereunder. (Ord. 2342, 9-20-2010)
A. Designation Of The Floodplain Administrator: The city of Mitchell director of public works or his/her designee is to administer and implement the provisions of this chapter and other appropriate sections of 44 CFR (national flood insurance program regulations) pertaining to floodplain management.
B. Duties And Responsibilities Of The Floodplain Administrator: Duties and responsibilities of the floodplain administrator shall include, but not be limited to, the following:
1. Maintain and hold open for public inspection all records pertaining to the provisions of this chapter.
2. Review permit application to determine whether proposed building site, including the placement of manufactured homes, will be reasonably safe from flooding.
3. Review, approve or deny all applications for development permits required by adoption of this chapter.
4. Review permits for proposed development to assure that all necessary permits have been obtained from those federal, state or local governmental agencies (including section 404 of the federal water pollution control act amendments of 1972, 33 USC 1334) from which prior approval is required.
5. Where interpretation is needed as to the exact location of the boundaries of the areas of special flood hazards (for example, where there appears to be a conflict between a mapped boundary and actual field conditions) the floodplain administrator shall make the necessary interpretation.
6. Notify, in riverine situations, adjacent communities and the state coordinating agency which is South Dakota emergency management, prior to any alteration or relocation of a watercourse, and submit evidence of such notification to the federal emergency management agency.
7. Assure that the flood carrying capacity within the altered or relocated portion of any watercourse is maintained.
8. When base flood elevation data has not been provided in accordance with subsection 12-1-3B of this section, the floodplain administrator shall obtain, review and reasonably utilize any base flood elevation data and floodway data available from a federal, state or other source, in order to administer the provisions of this chapter.
9. When a regulatory floodway has not been designated, the floodplain administrator must require that no new construction, substantial improvements, or other development (including fill) shall be permitted within zones A1-30 and AE on the community's FIRM, unless it is demonstrated that the cumulative effect of the proposed development, when combined with all other existing and anticipated development, will not increase the water surface elevation of the base flood more than one foot (1') at any point within the community.
10. Under the provisions of 44 CFR chapter 1, section 65.12, of the national flood insurance program regulations, a community may approve certain development in zones A1-30, AE, AH, on the community's FIRM which increases the water surface elevation of the base flood by more than one foot (1'), provided that the community first applies for a conditional FIRM revision through FEMA (conditional letter of map revision).
C. Permit Procedures:
1. Application for a development permit shall be presented to the floodplain administrator on forms furnished by him/her and may include, but not be limited to, plans in duplicate drawn to scale showing the location, dimensions, and elevation of proposed landscape alterations, existing and proposed structures, including the placement of manufactured homes, and the location of the foregoing in relation to areas of special flood hazard. Additionally, the following information is required:
a. Elevation (in relation to mean sea level), of the lowest floor (including basement) of all new and substantially improved structures;
b. Elevation in relation to mean sea level to which any nonresidential structure shall be floodproofed;
c. A certificate from a registered professional engineer or architect that the nonresidential floodproofed structure shall meet the floodproofing criteria of subsection 12-1-5B of this chapter;
d. Description of the extent to which any watercourse or natural drainage will be altered or relocated as a result of proposed development;
e. Maintain a record of all such information.
2. Approval or denial of a development permit by the floodplain administrator shall be based on all of the provisions of this chapter and the following relevant factors:
a. The danger to life and property due to flooding or erosion damage;
b. The susceptibility of the proposed facility and its contents to flood damage and the effect of such damage on the individual owner;
c. The danger that materials may be swept onto other lands to the injury of others;
d. The compatibility of the proposed use with existing and anticipated development;
e. The safety of access to the property in times of flood for ordinary and emergency vehicles;
f. The costs of providing governmental services during and after flood conditions including maintenance and repair of streets and bridges, and public utilities and facilities such as sewer, gas, electrical and water systems;
g. The expected heights, velocity, duration, rate of rise and sediment transport of the floodwaters and the effects of wave action, if applicable, expected at the site;
h. The necessity to the facility of a waterfront location, where applicable;
i. The availability of alternative locations, not subject to flooding or erosion damage, for the proposed use;
j. The relationship of the proposed use to the comprehensive plan for that area.
D. Variance Procedures: The appeal board shall hear and render judgement on requests for variances from the requirements of this chapter.
1. Any person or persons aggrieved by the decision of the appeal board may appeal such decision in the courts of competent jurisdiction.
2. The floodplain administrator shall maintain a record of all actions involving an appeal and shall report variances to the federal emergency management agency and the state office of emergency management upon issuing a variance.
3. Variances may be issued for new construction and substantial improvements to be erected on a lot of one-half (1/2) acre or less in size contiguous to and surrounded by lots with existing structures constructed below the base flood level, providing the relevant factors in subsection C of this section have been fully considered. As the lot size increases beyond the one-half (1/2) acre, the technical justification required for issuing the variance increases.
4. Upon consideration of the factors noted above and the intent of this chapter, the appeal board may attach such conditions to the granting of variances as it deems necessary to further the purpose and objectives of this chapter.
5. Variances shall not be issued within any designated floodway if any increase in flood levels during the base flood discharge would result.
6. Variances may be issued for the repair or rehabilitation of historic structures upon a determination that the proposed repair or rehabilitation will not preclude the structure's continued designation as a historic structure and the variance is the minimum necessary to preserve the historic character and design of the structure.
7. Prerequisites for granting variances:
a. Variances shall only be issued upon a determination that the variance is the minimum necessary, considering the flood hazard, to afford relief.
b. Variances shall only be issued upon:
(1) Showing a good and sufficient cause;
(2) A determination that failure to grant the variance would result in exceptional hardship to the applicant; and
(3) A determination that the granting of a 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 laws or ordinances.
Any applicant to whom a variance is granted shall be given written notice that the structure will be permitted to be built with the lowest floor elevation below the base flood elevation, and that the cost of flood insurance will be commensurate with the increased risk resulting from the reduced lowest floor elevation.
8. Variances may be issued by a community for new construction and substantial improvements and for other development necessary for the conduct of a functionally dependent use provided that:
a. The criteria outlined in subsections D1 through D7 of this section are met, and
b. The structure or other development is protected by methods that minimize flood damages during the base flood and create no additional threats to public safety.
9. A CLOMR is required only for those projects that will:
a. BFE/No floodway (demonstrate <1.0 foot increase):
(1) A project on a stream or river that has been studied through detailed hydrologic and hydraulic analyses and for which base flood elevations (BFEs) have been specified, but a floodway has not been designated. If the developer/property owner/community proposes to allow development that would result in more than a 1.0 foot increase in the BFE, a CLOMR must first be obtained.
(2) 44 CFR 60.3(c)(10): Result in an increase in the base flood water surface elevation (WSEL) of greater than 1.00 foot for streams with BFEs specified but no regulatory floodway designated.
b. BFE/Floodway (no rise):
(1) The second situation requiring a CLOMR is for a project on a stream or river for which detailed analyses have been conducted and BFEs and a floodway have been designated. If the community proposes to allow development totally or partially within the floodway that would result in any (greater than 0.0 foot) increase in the BFE, a CLOMR must be obtained.
(2) 44 CFR 60.3(d)(3): Result in any base flood WSEL increase from proposed construction within a regulatory floodway.
LOMRs are required under 44 CFR 65.3; optional for community to add language to ordinance. (Ord. 2342, 9-20-2010; amd. Ord. O2019-14, 8-19-2019)
A. General Standards: In all areas of special flood hazards the following provisions are required for all new construction and substantial improvements:
1. All new construction or substantial improvements shall 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;
2. All new construction or substantial improvements shall be constructed by methods and practices that minimize flood damage;
3. All new construction or substantial improvements shall be constructed with materials resistant to flood damage;
4. All new construction or substantial improvements shall be constructed with electrical, heating, ventilation, plumbing, and air conditioning equipment and other service facilities that are designed and/or located so as to prevent water from entering or accumulating within the components during conditions of flooding;
5. All new and replacement water supply systems shall be designed to minimize or eliminate infiltration of floodwaters into the system;
6. New and replacement sanitary sewage systems shall be designed to minimize or eliminate infiltration of floodwaters into the system and discharge from the systems into floodwaters; and
7. On site waste disposal systems shall be located to avoid impairment to them or contamination from them during flooding.
B. Specific Standards: In all areas of special flood hazards where base flood elevation data has been provided the following provisions are required:
1. Residential Construction: New construction and substantial improvement of any residential structure shall have the lowest floor (including basement), elevated to one foot (1') above the base flood elevation. A registered professional engineer, architect, or land surveyor shall submit a certification to the floodplain administrator that the standards of this chapter are satisfied.
2. Nonresidential Construction: New construction and substantial improvements of any commercial, industrial or other nonresidential structure shall either have the lowest floor (including basement) elevated to one foot (1') above the base flood level or together with attendant utility and sanitary facilities, be designed so that below the base flood level the structure is watertight with walls substantially impermeable to the passage of water and with structural components having the capability of resisting hydrostatic and hydrodynamic loads and effects of buoyancy. A registered professional engineer or architect shall develop and/or review structural design, specifications, and plans for the construction, and shall certify that the design and methods of construction are in accordance with accepted standards of practice as outlined in this subsection. A record of such certification which includes the specific elevation (in relation to mean sea level) to which such structures are floodproofed shall be maintained by the floodplain administrator.
3. Enclosures: New construction and substantial improvements, with fully enclosed areas below the lowest floor that are usable solely for parking of vehicles, building access or storage in an area other than a basement and which 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 architect or meet or exceed the following minimum criteria:
a. A minimum of two (2) openings 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.
b. The bottom of all openings shall be no higher than one foot (1') above grade.
c. Openings may be equipped with screens, louvers, valves, or other coverings or devices provided that they permit the automatic entry and exit of floodwaters.
4. Manufactured Homes:
a. Require that all manufactured homes to be placed within zone A on a community's FHBM or FIRM shall be installed using methods and practices which minimize flood damage. For the purposes of this requirement, manufactured homes must be elevated and 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. This requirement is in addition to applicable state and local anchoring requirements for resisting wind forces.
b. Require that manufactured homes that are placed or substantially improved within zones A1-30, AH, and AE on the community's FIRM on sites: 1) outside of a manufactured home park or subdivision, 2) in a new manufactured home park or subdivision, 3) in an expansion to an existing manufactured home park or subdivision, or 4) in an existing manufactured home park or subdivision on which a manufactured home has incurred "substantial damage" as a result of a flood, be elevated on a permanent foundation such that the lowest floor of the manufactured home is elevated to or above the base flood elevation and be securely anchored to an adequately anchored foundation system to resist flotation, collapse, and lateral movement.
c. In A1-30, AH, and AE zones, require that manufactured homes to be placed or substantially improved in an existing manufactured home park to be elevated so that the lowest floor is at or above the base flood elevation; or the chassis is supported by reinforced piers no less than thirty six inches (36") in height above grade and securely anchored.
5. Recreational Vehicles: Require that recreational vehicles placed on sites within zones A1-30, AH, and AE on the community's FIRM either:
a. Be on the site for fewer than one hundred eighty (180) consecutive days,
b. Be fully licensed and ready for highway use, or
c. Meet the permit requirements of subsection 12-1-4C of this chapter and the elevation and anchoring requirements for "manufactured homes" of this section. A recreational vehicle is ready for highway use if it is on its wheels or jacking system, is attached to the site only by quick disconnect type utilities and security devices, and has no permanently attached additions.
C. Standards For Subdivision Proposals:
1. All subdivision proposals including the placement of manufactured home parks and subdivisions shall be consistent with the provisions of this chapter.
2. All proposals for the development of subdivisions including the placement of manufactured home parks and subdivisions shall meet development permit requirements of this chapter.
3. Base flood elevation data shall be generated for subdivision proposals and other proposed development including the placement of manufactured home parks and subdivisions which is greater than fifty (50) lots or five (5) acres, whichever is lesser.
4. All subdivision proposals including the placement of manufactured home parks and subdivisions shall have adequate drainage provided to reduce exposure to flood hazards.
5 All subdivision proposals including the placement of manufactured home parks and subdivisions shall have public utilities and facilities such as sewer, gas, electrical and water systems located and constructed to minimize or eliminate flood damage.
D. Standards For Areas Of Shallow Flooding (AO/AH Zones): Located within the areas of special flood hazard established in subsection 12-1-3B of this chapter, are areas designated as shallow flooding. These areas have special flood hazards associated with base flood depths of one to three feet (3') where a clearly defined channel does not exist and where the path of flooding is unpredictable and where velocity flow may be evident. Such flooding is characterized by ponding or sheet flow; therefore, the following provisions apply:
1. All new construction and substantial improvements of residential structures have the lowest floor (including basement) elevated above the highest adjacent grade at least as high as the depth number specified in feet on the community's FIRM (at least 2 feet if no depth number is specified).
2. All new construction and substantial improvements of nonresidential structures:
a. Have the lowest floor (including basement) elevated above the highest adjacent grade at least as high as the depth number specified in feet on the community's FIRM (at least 2 feet if no depth number is specified), or
b. Together with attendant utility and sanitary facilities be designed so that below the base flood level the structure is watertight with walls substantially impermeable to the passage of water and with structural components having the capability of resisting hydrostatic and hydrodynamic loads of effects of buoyancy.
3. A registered professional engineer or architect shall submit a certification to the floodplain administrator that the standards of this section, as proposed in subsection 12-1-4C1a of this chapter, are satisfied.
4. Require within zones AH or AO adequate drainage paths around structures on slopes, to guide floodwaters around and away from proposed structures.
E. Floodways: Floodways located within areas of special flood hazard established in section 12-1-3 of this chapter, are extremely hazardous areas due to the velocity of floodwaters which carry debris, potential projectiles and erosion potential, the following provisions shall apply:
1. Designate a regulatory floodway which will not increase the base flood level more than one foot (1').
2. Encroachments are prohibited, including fill, new construction, substantial improvements and other development within the adopted regulatory floodway unless it has been demonstrated through hydrologic and hydraulic analyses performed in accordance with standard engineering practice that the proposed encroachment would not result in any increase in flood levels within the community during the occurrence of the base flood discharge.
3. All new construction and substantial improvements shall comply with all applicable flood hazard reduction provisions of this section.
4. Under the provisions of 44 CFR chapter 1, section 65.12, of the national flood insurance regulations, a community may permit encroachments within the adopted regulatory floodway that would result in an increase in base flood elevations, provided that the community first applies for a conditional FIRM and floodway revision through FEMA.
F. Penalties For Noncompliance: In accordance with section 59.2(b) of CFR 44, chapter 1, of the national flood insurance program (NFIP) regulation, to qualify for the sale of federally subsidized flood insurance, a community must adopt floodplain management regulations that meets or exceeds the minimum standards of section 60. "These regulations must include effective enforcement provisions." In accordance with section 60.1(b) of CFR 44, chapter 1, of the NFIP regulations, "These regulations must be legally enforceable, applied uniformly throughout the community to all privately and publicly owned land within flood prone (i.e., mudflow) or flood related erosion areas, and the community must provide that the regulations take precedence over less restrictive conflicting local laws, ordinances or codes."
No structure or land shall hereafter be constructed, located, extended, converted, or altered without full compliance with the terms of this chapter and other applicable regulations. Violation of the provisions of this chapter by failure to comply with any of its requirements (including violations of conditions and safeguards established in connection with conditions) shall constitute a misdemeanor. Any person who violates this chapter or fails to comply with any of its requirements shall upon conviction thereof be fined not to exceed the current maximum penalty for conviction of a class 2 misdemeanor from time to time in effect under South Dakota code or imprisoned for not more than thirty (30) days, or both, for each violation, and in addition shall pay all costs and expenses involved in the case. Nothing herein contained shall prevent the city of Mitchell from taking such other lawful action as is necessary to prevent or remedy any violation. (Ord. 2342, 9-20-2010)
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