In all SFHAs where the base flood elevation data or flood depths have been provided, as set forth in § 155.021, the following provisions are required:
(A) In addition to the requirements of § 155.045, all structures to be located in the SFHA shall be protected from flood damage below the FPG. This building protection requirement applies to the following situations:
(1) Construction or placement of any structure(residential or non-residential).
(2) Addition or improvement made to any existing structure where the cost of the addition or improvement equals or exceeds 40% of the value of the existing structure (excluding the value of the land).
(3) Reconstruction or repairs made to a damaged structure where the costs of restoring the structure to it’s before damaged condition equals or exceeds 40% of the market value of the structure (excluding the value of the land) before damage occurred (the costs of any proposed additions or improvements beyond restoring the damaged structure to its before damaged condition must be included in the cost).
(4) Installing a travel trailer or recreational vehicle on a site for more than 180 days.
(5) Installing a manufactured home on a new site or a new manufactured home on an existing site. This chapter does not apply to returning the existing manufactured home to the same site it lawfully occupied before it was removed to avoid flood damage.
(6) Reconstruction or repairs made to a repetitive loss structure.
(7) Addition or improvement made to any existing structure with a previous repair, addition or improvement constructed since the community’s first floodplain ordinance.
(B) Residential structures (excluding manufactured homes). New construction or substantial improvement of any residential structure shall meet provision described in § 155.046(D).
(1) In Zone A and Zone AE, new construction or substantial improvement of any residential structure (excluding accessory structures) shall have the lowest floor, including basement, elevated to or above the FPG (two feet above the base flood elevation). Should solid foundation perimeter walls be used to elevate a structure, openings sufficient to facilitate the unimpeded movements of floodwaters shall be provided in accordance with the standards of § 155.046(B)(4). Should fill be used to elevate a structure, the standards of § 155.046 must be met.
(2) Fully enclosed areas formed by foundation and other exterior walls below the flood protection grade shall meet the following requirement:
(a) Designed to preclude finished living space and designed to allow for the automatic entry and exit of floodwaters to equalize hydrostatic flood forces on exterior walls. Flood openings must be designed and installed in compliance with criteria set out in FEMA Technical Bulletin 1. Engineered flood openings must be designed and certified by a registered design professional (requires supporting engineering certification or make/model specific ICC-ES Report), or meet the following criteria for non-engineered flood openings:
1. Provide a minimum of two openings on different sides of an enclosure. If more than one enclosed area is present, each must have openings on exterior walls (having a total net area of not less than one square inch for every one square foot of enclosed area);
2. The bottom of all opening shall be no more than one foot above the higher of the final interior grade (or floor) and the finished exterior grade immediately under each opening;
3. If the floor of the enclosure is below the BFE, the openings must be located wholly below the BFE.
4. If the floor of the enclosure is below the BFE, but below FPG, the openings must be located wholly below the FPG;
5. Doors and windows do not qualify as openings;
6. Openings may be equipped with screens, louvers, valves or other coverings or devices provided they permit the automatic flow of floodwaters in both directions;
7. Openings are to be not less than three inches in any direction in the plane of the wall. This requirement applied to the hole in the wall, excluding any device that may be inserted such as typical foundation air vent device.
(b) The floor of such enclosed area must be at or above grade on at least one side.
(c) The interior portion of such enclosed area shall not be partitioned or finished into separate rooms.
(3) A residential structure may be constructed on fill in accordance with the following:
(a) Fill shall be placed in layers no greater than one foot deep before compacting to 95% of the maximum density obtainable with either the Standard or Modified Proctor Test method. The results of the test showing compliance shall be retained in the permit file;
(b) Fill shall extent ten feet beyond the foundation of the structure before sloping below the BFE;
(c) Fill shall be protected against erosion and scour during flooding by vegetative cover, riprap, or bulk heading. If vegetative cover is used, the slopes shall be no steeper than three inches horizontal to one foot vertical;
(d) Fill shall not adversely affect the flow of surface drainage from or onto neighboring properties;
(e) Fill shall be composed of clean granular or earthen material.
(4) A residential structure may be constructed using a stem wall foundation (all called chain wall, raised-slab-on-grade, and slap-on-stem-wall-with-fill) must be backfilled with compacted structural fill, concrete, or gravel that supports the floor slab. No flood openings are required for this type of construction.
(C) Non-residential structures.
(2) In Zone A and Zone AEnew construction or substantial improvement of any commercial, industrial, or non-residential structure(excluding accessory structures) shall either have the lowest floor, including basement, elevated to or above the FPG (two feet above the base flood elevation) or be floodproofed to or above the FPG. Should solid foundation perimeter walls be used to elevate a structure, openings sufficient to facilitate the unimpeded movements of floodwaters shall be provided in accordance with the standards of § 155.046(D). Should fill be used to elevate a structure, the standards of § 155.046(C)(4) must be met.
(3) Fully enclosed areas formed by foundation and other exterior walls below the flood protection grade shall meet the following requirement:
(a) Designed to preclude finished living space and designed to allow for the automatic entry and exit of floodwaters to equalize hydrostatic flood forces on exterior walls. Flood openings must be designed and installed in compliance with criteria set out in FEMA Technical Bulletin 1. Engineered flood openings must be designed and certified by a registered design professional (requires supporting engineering certification or make/model specific ICC-ES Report), or meet the following criteria for non-engineered flood openings:
1. Provide a minimum of two openings on different sides of an enclosure. If more than one enclosed area is present, each must have openings on exterior walls (having a total net area of not less than one square inch for every one square foot of enclosed area);
2. The bottom of all opening shall be no more than one foot above the higher of the final interior grade (or floor) and the finished exterior grade immediately under each opening;
3. If the floor of the enclosure is below the BFE, the openings must be located, wholly below the BFE;
4. If the floor of the enclosure is below the BFE, but below FPG, the openings must be located wholly below the FPG;
5. Doors and windows do not qualify as openings;
6. Openings may be equipped with screens, louvers, valves or other coverings or devices provided they permit the automatic flow of floodwaters in both directions;
7. Openings are to be not less than three inches in any direction in the plane of the wall. This requirement applied to the hole in the wall, excluding any device that may be inserted such as typical foundation air vent device.
(b) The floor of such enclosed area must be at or above grade on at least one side.
(c) The interior portion of such enclosed area shall not be partitioned or finished into separate rooms.
(4) A non-residential structure may be constructed on fill in accordance with the following:
(a) Fill shall be placed in layers no greater than one foot deep before compacting to 95% of the maximum density obtainable with either the Standard or Modified Proctor Test method. The results of the test showing compliance shall be retained in the permit file;
(b) Fill shall extend ten feet beyond the foundation of the structure before sloping below the BFE;
(c) Fill shall be protected against erosion and scour during flooding by vegetative cover, riprap, or bulk heading. If vegetative cover is used, the slopes shall be no steeper than three inches horizontal to one foot vertical;
(d) Fill shall not adversely affect the flow of surface drainage from or onto neighboring properties;
(e) Fill shall be composed of clean granular or earthen material.
(5) A non-residential structure may be floodproofed in accordance with the following:
(a) A registered professional engineer or architect shall certify that the structure has been designed so that below the FPG, the structure and attendant utility facilities are watertight and capable of resisting the effects of the regulatory flood. The structure design shall take into account flood velocities, duration, rate of rise, hydrostatic pressures, and impacts from debris or ice. Such certification shall be provided to the Floodplain Administrator as set forth in § 155.037(B)(22).
(b) Floodproofing measures shall be operable without human intervention and without an outside source of electricity.
(6) A non-residential structure may be constructed using a stem wall foundation (also called chain wall, raised-slab-on-grade, and slab-on-stem-wall-with-fill). Any backfilled stem wall foundation must be backfilled with compacted structural fill, concrete, or gravel that supports the floor slab. No flood openings are required for this type of construction.
(D) Elevated structures.
(1) New construction or substantial improvements of elevated structures shall have the lowest floor at or above the FPG.
(2) Elevated structures with fully enclosed areas formed by foundation and other exterior walls below the flood protection grade shall be designed to preclude finished living space and designed to allow for the entry and exit of floodwaters to automatically equalize hydrostatic flood forces on exterior walls. Designs must meet the following minimum criteria:
(a) Provide a minimum of two openings located in a minimum of two exterior walls (having a total net area of not less than one square inch for every one square foot of enclosed area).
(b) The bottom of all openings shall be no more than one foot above the exterior grade or the interior grade immediately beneath each opening, whichever is higher.
(c) Openings may be equipped with screens, louvers, valves or other coverings or devices provided they permit the automatic flow of floodwaters in both directions.
(d) Access to the enclosed area shall be the minimum necessary to allow for parking for vehicles (garage door) or limited storage of maintenance equipment used in connection with the premises (standard exterior door) or entry to the living area (stairway or elevator).
(e) The interior portion of such enclosed area shall not be partitioned or finished into separate rooms.
(f) The interior grade of such enclosed area shall be at an elevation at or higher than the exterior grade.
(g) Openings are to be not less than three inches in any direction in the plane of the wall. This requirement applies to the hole in the wall, excluding any device that may be inserted such as typical foundation air vent device.
(h) Property owners shall be required to execute a flood openings/venting affidavit acknowledging that all openings will be maintained as flood vents, and that the elimination or alteration of the openings in any way will violate the requirements of § 155.046(D). Periodic inspections will be conducted by the Floodplain Administrator to ensure compliance. The affidavit shall be recorded, along with the deed, in the office of the Adams County Recorder.
(i) Property owners shall be required to execute and record with the structure's deed a non-conversion agreement declaring that the area below the lowest floor (where the interior height of the enclosure exceeds six feet) shall not be improved, finished or otherwise converted; the community will have the right to inspect the enclosed area. The non-conversion agreement shall be recorded in the office of the Adams County Recorder.
(E) Standards for manufactured homes and recreational vehicles. Manufactured homes and recreational vehicles to be installed or substantially improved on a site for more than 180 days must meet one of the following requirements:
(1) These requirements apply to all manufactured homes to be placed on a site outside a manufactured home park or subdivision; in a new manufactured home park or subdivision; in an expansion to an existing manufactured home park or subdivision; or in an existing manufactured home park or subdivision on which a manufactured home has incurred substantial damage as a result of a flood:
(a) The manufactured home shall be elevated on a permanent foundation such that the lowest floor shall be at or above the FPG and securely anchored to an adequately anchored foundation system to resist flotation, collapse, and lateral movement.
(b) Fully enclosed areas formed by foundation and other exterior walls below the FPG shall be designed to preclude finished living space and designed to allow for the entry and exit of floodwaters to automatically equalize hydrostatic flood forces on exterior walls as required for elevated structures in § 155.046(D).
(c) Flexible skirting and rigid skirting not attached to the frame or foundation of a manufactured home are not required to have openings.
(F) Recreational vehicles placed on a site shall either:
(1) Be on site for less than 180 days;
(2) Be fully licensed and ready for highway use (defined as being 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); or
(3) Meet the requirements for manufactured homes as stated earlier in this section.
(G) Freestanding pavilions, gazebos, decks, carports, and similar development. Within SFHAs, new construction or placement of pavilions, gazebos, decks, carports, and similar development must meet the following standards:
(1) Shall have open sides (having more than one rigid wall);
(2) Shall be anchored to prevent flotation or lateral movement;
(3) Shall be constructed of flood resistant materials below the FPG;
(4) Any electrical, heating, plumbing, and other service facilities shall be located at/above the FPG;
(5) Shall not have subsequent additions or improvements that would preclude the development from its continued designation as a pavilion, gazebo, carport, or similar open-sided development.
(H) Accessory structures. Relief to the elevation or dry floodproofing standards may be granted for accessory structures. Such structures must meet the following standards:
(1) Shall not be used for human habitation.
(2) Shall have a floor area of 400 square feet or less.
(3) Use shall be limited to parking of vehicles and limited storage.
(4) Shall be constructed of flood resistant materials.
(5) Shall be constructed and placed on the lot to offer the minimum resistance to the flow of floodwaters.
(6) Shall be firmly anchored to prevent flotation.
(7) Service facilities such as electrical and heating equipment shall be elevated or floodproofed to or above the FPG.
(8) Shall be designed to allow for the entry and exit of floodwaters to automatically equalize hydrostatic flood forces on exterior walls as required for elevated structures in § 155.046(D).
(9) Shall not have subsequent additions or improvements that would preclude the structure from its continued designation as an accessory structure.
(I) Above ground gas or liquid storage tanks. Within SFHAs designated as Zone A, AE on the community’s FIRM, all newly placed aboveground gas or liquid storage tanks shall meet the requirements for a non-residential structure as required in § 155.046.
(Ord. 2017-7, passed 8-15-2017; Ord. 2022-10, passed 6-21-2022)