City of Mission, KS Article IV Provisions For Flood Hazard Reduction

Section 460.140 General Standards.

[Ord. No. 1054 Art. 4 §A, 9-11-2002; Ord. No. 1091 §§1 — 3(App. A §460.140), 9-24-2003; Ord. No. 1288, 2-27-2009]

A. No permit for floodplain development shall be granted for new construction, substantial improvements and other improvements, including the placement of manufactured homes, within any numbered or unnumbered A Zones, AE, AO and AH Zones, unless the conditions of this Section are satisfied.

B. All areas identified as unnumbered A Zones on the FIRM are subject to inundation of the 100-year flood; however, the base flood elevation is not provided. Development within unnumbered A Zones is subject to all provisions of this Chapter. If Flood Insurance Study data is not available, the community shall obtain, review and reasonably utilize any base flood elevation or floodway data currently available from Federal, State or other sources.

C. All new construction, subdivision proposals, substantial improvements, prefabricated structures, placement of manufactured homes and other developments shall require:

1. Design or adequate anchorage to prevent flotation, collapse or lateral movement of the structure resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy;

2. Construction with materials resistant to flood damage;

3. Utilization of methods and practices that minimize flood damages;

4. All electrical wiring, heating, ventilation, plumbing, air-conditioning equipment, and other service facilities be designed and/or located so as to prevent water from entering or accumulating within the mechanical components during conditions of flooding. All outdoor electrical meters shall be installed at the minimum flood protection elevation;

5. New or replacement water supply systems and/or sanitary sewage systems be designed to minimize or eliminate infiltration of floodwaters into the systems and discharges from the systems into floodwaters, and on-site waste disposal systems be located so as to avoid impairment or contamination from them during flooding; and

6. Subdivision proposals and other proposed new development, including manufactured home parks or subdivisions, located within special flood hazard areas are required to assure that:

a. All such proposals are consistent with the need to minimize flood damage;

b. All public utilities and facilities, such as sewer, gas, electrical and water systems, are located and constructed to minimize or eliminate flood damage;

c. Adequate drainage is provided so as to reduce exposure to flood hazards; and

d. All proposals for development, including proposals for manufactured home parks and subdivisions, of five (5) acres or fifty (50) lots, whichever is lesser, include within such proposals base flood elevation data.

D. Storage, Material And Equipment.

1. The storage or processing of materials within the special flood hazard area that are in time of flooding buoyant, flammable, explosive or could be injurious to human, animal or plant life is prohibited.

2. Storage of other material or equipment may be allowed if not subject to major damage by floods, if firmly anchored to prevent flotation, or if readily removable from the area within the time available after a flood warning.

3. Storage of materials or equipment that, in the time of flooding, could become buoyant and pose an obstruction to flow in the identified floodway areas is prohibited.

E. Non-Conforming Use. A structure or the use of a structure or premises that was lawful before the passage or amendment of the Chapter, but which is not in conformity with the provisions of this Chapter, may be continued subject to the following conditions:

1. If such structure, use or utility service is discontinued for six (6) consecutive months, any future use of the building shall conform to this Chapter.

2. If any non-conforming 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 pre-damaged market value of the structure. This limitation does not include the cost of any alteration to comply with existing State or local health, sanitary, building, safety codes, regulations or the cost of any alteration of a structure listed on the National Register of Historic Places, the State Inventory of Historic Places, or Local Inventory of Historic Places upon determination.

F. Compensatory Storage Required For Earthwork Involving Fill.

1. Fill within the area of special flood hazard shall result in no net loss of natural floodplain storage. The volume of the loss of floodwater storage due to filling in the special flood hazard area shall be offset by providing an equal volume of flood storage by excavation or other compensatory measures at or adjacent to the development site.

2. This compensatory storage requirement does not apply to small temporary structures (such as above ground swimming pools) where such projects are located on small lots with existing buildings and where the site does not have sufficient space to provide compensatory storage.

G. Critical Facilities.

1. Critical facilities are those which: are critical to the community's public health and safety; are essential to the orderly functioning of a community; store, or produce highly volatile, toxic or water-reactive materials; or house occupants that may be insufficiently mobile to avoid loss of life or injury. Examples of critical facilities include: jails or other detention facilities, hospitals, schools, police stations, fire and emergency services stations, nursing homes, water plants, wastewater treatment facilities and fuel storage facilities.

2. Critical facilities shall be elevated at least one (1) foot above the 500-year flood elevation or to the highest known historical flood elevation (if records are available), whichever is greater. If no data exists establishing a 500-year flood elevation or the highest known historical flood elevation, the applicant shall provide a hydrologic and hydraulic engineering analysis that generates 500-year flood elevation data.

3. Critical facilities shall only be constructed in the 500-year floodplain if they are placed on engineered fill and/or if the lowest floor (including basement) is at least one (1) foot above the 500-year flood elevation. A critical facility shall have at least one (1) access drive or road constructed to connect to land higher than the 500-year flood elevation and this drive or road shall be capable of supporting a four thousand (4,000) pound vehicle. The top of the drive or road shall be at or above the 500-year flood elevation.

Section 460.150 Specific Standards.

[Ord. No. 1054 Art. 4 §B, 9-11-2002; Ord. No. 1091 §§1 — 3(App. A §460.150), 9-24-2003; Ord. No. 1288, 2-27-2009]

A. In all areas identified as numbered and unnumbered A Zones, AE and AH Zones, where base flood elevation data have been provided as set forth in Article IV, Section 460.140(B), the following provisions are required:

1. All new construction. A residential or non-residential building, including manufactured housing, shall be constructed on a foundation that meets one (1) or more of the following requirements:

a. The lowest floor, including the basement of the building or building addition, shall be at or above the base flood elevation;

b. When fill is used for the building pad, it shall be placed in layers no greater than twelve (12) inches deep before compacting and should extend beyond the foundation walls at a slope no greater than 3:1. When fill is used, the top layer shall be above the base flood elevation;

c. No fill shall be placed within ten (10) feet of the property line. The prohibition of fill within ten (10) feet of a property line can be waived by a structural engineer's certification that an alternative method will protect the building from damage due to erosion, scour and other hydrological forces.

d. Fill shall not adversely affect the flow or surface drainage from or onto neighboring properties.

2. Residential construction. New construction or substantial improvements of any residential structures, including manufactured housing, shall have the lowest floor, including basements, elevated to at least two (2) feet above the base flood elevation. The elevation of the lowest floor shall be certified by a licensed land surveyor or professional engineer. Such certification shall be provided to the Floodplain Administrator as set forth in Article III, Section 460.120(7 — 9). All new construction located in the area behind a flood levee shall be elevated a minimum of two (2) feet above the lowest adjacent grade.

Each new residential site shall have direct access to a walkway, driveway or street whose surface elevation is at least one (1) foot above the base flood elevation and such escape route shall lead directly out of the floodplain area.

3. Non-residential construction. New construction or substantial improvements of any non-residential structure, including manufactured housing, shall have the lowest floor, including basements, elevated to at least two (2) feet above the base flood elevation or, together with attendant utility and sanitary facilities, be floodproofed to the minimum flood protection elevation so that all areas of the building (including mechanical and utility equipment) below the required elevation are 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 certify that the standards of this Subsection are satisfied. The elevation of the lowest floor shall be certified by a licensed land surveyor or professional engineer. Such certification shall be provided to the Floodplain Administrator as set forth in Article III, Section 460.120(7 — 9). All new construction located in the area behind a flood levee shall be elevated a minimum of two (2) feet above the lowest adjacent grade.

Each new residential site shall have direct access to a walkway, driveway or street whose surface elevation is at least one (1) foot above the base flood elevation and such escape route shall lead directly out of the floodplain area.

4. Require, for all new construction or substantial improvement, that fully enclosed areas below the base flood elevation used solely for parking of vehicles, building access or storage in an area other than a basement and that areas subject to flooding shall be limited to four hundred (400) square feet and 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 and meet or exceed the following minimum criteria:

a. The structure must provide one (1) square inch of venting for every square foot of enclosed area;

b. The structure must provide at least two (2) vents located on different sides of the structure, with one (1) being located on the upstream side of the structure, if possible;

c. The bottom of required vents must be no higher than one (1) foot above grade;

d. The required vents must be freely open with no human interventions required and be equipped with screens, louvers, valves or other coverings or devices provided that they permit automatic entry and exit of floodwaters;

e. The area below the base flood elevation must be unfinished and constructed of flood-resistant materials as the same are defined by FEMA. Sheetrock or drywall used for fire protection is permitted in unfinished areas;

f. All ductwork, heating, ventilation and air-conditioning systems, electrical and hot water heaters included as part of the structure must be elevated a minimum of one (1) foot above the base flood elevation;

g. All of the above required features must be shown on the plan submitted for the floodplain development permit (and, if applicable, the building permit);

h. An elevation certificate must document the venting features included in a structure and be filed with the Floodplain Administrator before the structure is occupied.

5. Development. Any development, including fill, new construction, substantial improvements or other types of encroachment, is prohibited within a floodway.

Section 460.160 Manufactured Homes.

[Ord. No. 1054 Art. 4 §C, 9-11-2002; Ord. No. 1091 §§1 — 3(App. A §460.160), 9-24-2003; Ord. No. 1288, 2-27-2009]

A. All manufactured homes to be placed within all unnumbered and numbered A Zones, AE and AH Zones on the community's FIRM shall be required to be installed using methods and practices that 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 manufactured homes that are placed or substantially improved within unnumbered or numbered A Zones, AE and AH Zones 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 mobile home park or subdivision or whenever a manufactured home has incurred substantial damage as the result of a flood, the replacement manufactured home shall be elevated on a permanent foundation so the lowest floor of the manufactured home is at least two (2) feet above the base flood elevation (BFE) and securely attached to an adequately anchored foundation system to resist flotation, collapse and lateral movement. The elevation of the lowest floor shall be certified by a licensed land surveyor or professional engineer.

C. Require that manufactured homes to be placed or substantially improved on sites in an existing manufactured home park within all unnumbered and numbered A Zones, AE and AH Zones on the community's FIRM, and not subject to the provisions of Article IV, Section 460.160(B) of this Chapter, be elevated so the lowest floor of the manufactured home is at least two (2) feet above the base flood elevation (BFE). The elevation of the lowest floor shall be certified by a licensed land surveyor or professional engineer.

Section 460.170 Areas of Shallow Flooding (AO and AH Zones).

[Ord. No. 1054 Art. 4 §D, 9-11-2002; Ord. No. 1091 §§1 — 3(App. A §460.170), 9-24-2003; Ord. No. 1288, 2-27-2009]

A. Located within the areas of special flood hazard as described in Article II, Section 460.040 are areas designated as AO Zones. These areas have special flood hazards associated with base flood depths of one (1) to three (3) feet where a clearly defined channel does not exist and where the path of flooding is unpredictable and indeterminate. The following provisions apply:

1. AO Zones.

a. All new construction and substantial improvements of residential structures, including manufactured homes, shall 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 two (2) feet if no depth number is specified).

b. All new construction and substantial improvements of any commercial, industrial or other non-residential structures, including manufactured homes, shall 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 two (2) feet if no depth number is specified) or, together with attendant utilities and sanitary facilities, be completely floodproofed to that level so that 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.

c. Adequate drainage paths shall be required around structures on slopes in order to guide floodwaters around and away from proposed structures.

2. AH Zones.

a. The specific standards for all areas of special flood hazard where base flood elevation has been provided shall be required as set forth in Article IV, Section 460.150.

b. Adequate drainage paths shall be required around structures on slopes in order to guide floodwaters around and away from proposed structures.

Section 460.180 Floodway.

[Ord. No. 1054 Art. 4 §E, 9-11-2002; Ord. No. 1091 §§1 — 3(App. A §460.180), 9-24-2003; Ord. No. 1288, 2-27-2009]

A. Located within areas of special flood hazard established in Article II, Section 460.040 are areas designated as floodways. Since the floodway is an extremely hazardous area due to the velocity of floodwaters that carry debris and potential projectiles, the following provisions shall apply:

1. The community shall select and adopt a regulatory floodway based on the principle that the area chosen for the regulatory floodway must be designed to carry the waters of the base flood without increasing the water surface elevation of that flood more than one (1) foot at any point.

2. Any encroachments, including fill, new construction, substantial improvements or other development, within the adopted regulatory floodway is prohibited.

3. If Article IV, Section 460.180(2) is satisfied, all new construction and substantial improvements shall comply with all applicable flood hazard reduction provisions of Article IV.

4. In unnumbered A Zones, the community shall obtain, review and reasonably utilize any base flood elevation or floodway data currently available from Federal, State or other sources as set forth in Article IV, Section 460.140(B).

Section 460.190 Recreational Vehicles.

[Ord. No. 1054 Art. 4 §F, 9-11-2002; Ord. No. 1091 §§1 — 3(App. A §460.190), 9-24-2003; Ord. No. 1288, 2-27-2009]

A. Require that recreational vehicles placed on sites within all unnumbered and numbered A Zones, AE, AH and AO Zones on the community's FIRM either:

1. Be on the site for fewer than one hundred eighty (180) consecutive days; or

2. Be fully licensed and ready for highway use*; or

3. Meet the permitting, elevation and anchoring requirements for manufactured homes of this Chapter.

* 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.