Design and Construction Standards. In order to prevent excessive damage to buildings, structures and related utilities and facilities, the following restrictions apply to all development, subdivision proposals, manufactured home parks, and new construction and to construction of substantial improvements to existing structures occurring in the Floodplain Area.
(a) Basement and lowest floors.
(1) All new construction, relocation and substantial improvements of residential structures must have the lowest floor (including basement) elevated to one foot six inches above the Base Flood Elevation.
(2) All new construction, relocation and substantial improvements of nonresidential structures must have the lowest floor (including basement) elevated to one foot six inches above the Base Flood Elevation; or, together with attendant utility and sanitary facilities, be designed so that below the Base Flood Elevation plus one foot and six inches of freeboard the structure is floodproofed in accordance with Section 1741.05(c)(2).
(3) For all new construction, relocation and substantial improvements, those fully enclosed areas below the lowest floor that are usable solely for parking of vehicles, building access or storage in an area other than basement and which are subject to flooding shall be designed to automatically equalize hydrostatic flood forces on exterior walls by allowing for 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 openings having a total net area of not less than one square inch for every foot of enclosed area subject to flooding shall be provided.
B. The bottom of all openings shall be no higher than one foot above grade.
C. Openings may be equipped with the screens, louvers, valves, or other coverings or device provided that they permit the automatic entry and exit of floodwaters.
(b) Manufactured home placement. Manufactured homes to be placed or substantially within the floodplain area shall:
(1) When manufactured home is placed or substantially improved by a Licensed Manufactured Home installer.
A. Be elevated on reinforced piers or other foundation elements of at least equivalent strength on a permanent foundation so that the lowest floor of the manufactured home is elevated to one foot six inches above the Base Flood Elevation and,
B. Be securely anchored to an adequately anchored foundation system to resist flotation, collapse and lateral movement.
(2) When a manufactured home is placed or substantially improved by a Licensed Manufactured Home Installer. Comply with the requirements of 42 CSR Series 19, Sections 10.1, 10.2 and 10b as authorized by West Virginia Code 21-9. Any one of three methods are authorized for use when installing a Manufactured Home.
A. Manufacturer's installation manual. This method may be used only if the Manufacturer's manual explicitly states that the installation design it contains is approved for use in a flood hazard or floodplain area.
B. ANSI 225.1 standard installation method. This standard is for use only outside of flood hazard areas. The specifications explicitly state that a registered professional engineer's design is required to install a manufactured home in a Floodplain.
C. Installation using a design approved and sealed by registered professional engineer for use in a flood hazard area.
(3) Regardless of the method chosen for installation, all Manufactured Homes must be securely anchored to an adequately anchored foundation system to resist flotation, collapse and lateral movement.
(c) Appurtenant structures.
(1) Where feasible, appurtenant structures and detached and attached garages shall be located out of the floodplain area or elevated one foot six inches above the Base Flood Elevation.
(2) Where necessary structures are to be located on sites below the Base Flood Elevation, the following flood damage reduction provisions apply:
A. Structures shall be no more than 600 square reduction provisions apply:
B. Floors shall be at or above grade.
C. Structures shall be located, oriented and constructed to minimize flood damage.
D. Structures shall be designed (or modified) and adequately anchored to prevent flotation, collapse, or lateral movement of the structure resulting from hydrodynamic loads, including the effects of buoyancy.
E. Flood resistant materials such as those listed in FEMA Technical Bulletin 2-93 (FIA-TB-2) shall be used in the construction of the structure to at least two feet above the Base Flood Elevation.
F. Machinery, electric devices or appliances and all utilities shall be located at least two feet above the base flood elevation.
G. The venting requirements contained in subsection (a) hereof are applicable and shall be strictly adhered to.
(3) A Nonconversion Agreement shall be signed by the applicant stating that the use of accessory structure or detached or attached garage shall not be changed from the use permitted, acknowledging that the structure may be subject to greater flood risk and that higher flood insurance premiums may be possible, and that a change in use may require full compliance with this article. It shall be the responsibility of the applicant to have the agreement referenced in and recorded with the deed of the subject property before a permit can be issued.
(d) Recreational vehicle placement . Recreational vehicles to be placed within any floodplain area shall either:
(1) Be on site for fewer than 180 consecutive days and
(2) Be fully licensed and ready for highway use or meet the provision of subsection (b)(1) and (3) hereof. A recreational vehicle is ready for highways use if it is on its wheels or jacking system, is attached to the site only by quick disconnect utilities and security devices, and has no permanently attached additions.
(e) Fill. Ripley officially recognizes the natural and beneficial functions of the floodplain thus placement of fill in the floodplain area is discouraged and shall be minimized. In the floodway, no fill shall be permitted unless it meets the requirements of Section 1741.04(a). Any fill proposed to be deposited in the floodway must be shown to have some beneficial purpose, as demonstrated by a plan submitted by the owner showing the uses to which the filled land will be put and the final dimensions of the proposed fill or other materials. All fill placed in the floodplain shall meet or exceed the following standards.
(1) Fill shall be used only to the extent to which it does not adversely affect adjacent properties. The County may require the applicant to show through hydrologic and hydraulic engineering techniques that proposed fill will not adversely affect adjacent properties. Hydrologic and hydraulic analyses shall be undertaken only by registered professional engineers or others of demonstrated qualifications, who shall certify that the technical methods used correctly reflect currently accepted technical concepts. The resultant study shall include a cover letter, signed by the responsible professional, providing a statement of findings in layman's terms. In addition the County shall submit studies, analyses, computations, etc., in sufficient detail to allow a thorough technical review.
(2) Fill shall be used only to the extent to which it does not adversely affect the capacity of channels or floodways to any tributary to the main stream, drainage ditch, or any other drainage facility or system.
(3) Fill shall extend beyond a structure for sufficient distance to provide acceptable access. For residential structures, fill shall extend latterly fifteen (15) feet beyond the building line shall be provided to a minimum of twenty-five (25) percent of the perimeter of a nonresidential structure.
(4) Fill shall consist of soil or rock material only. Sanitary landfills shall not be permitted.
(5) Fill material shall be compacted to provide the necessary stability and resistance to erosion, scouring or settling.
(6) Fill slopes shall be no steeper than one (1) vertical on two (2) horizontal, unless substantiating data justifying steeper are submitted to and approved by the Floodplain Administrator.
(7) Fill shall be protected against erosion by rip-rap, vegetation cover, or bulkheading.
(f) Placement of buildings. All buildings and structures shall be constructed and placed on the lot as to offer the minimum obstruction to the flow of water and shall be designed to have a minimum obstruction effect upon the flow and height of floodwater.
(1) Whenever possible, structures shall be constructed with the longitudinal axis parallel to the direction of flood flow, and
(2) So far as practicable, structures shall be placed approximately on the same flood-flow lines as those of adjoining structures.
(g) Anchoring.
(1) All buildings and structures shall be firmly anchored in accordance with accepted engineering practices to prevent flotation, collapse, and lateral movement, thus reducing the threat to life and property and decreasing the possibility of the blockage of bridge openings and other restricted sections of the watercourse.
(2) All air ducts, large pipes and storage tanks located at or below the Base Flood Elevation shall be firmly anchored to resist flotation.
(3) All manufactured homes shall be in compliance with the requirements of 42 CSR Series 19, Sections 10.1, 10.2 and 10b as authorized by West Virginia Code Chapter 21-9. This anchoring shall be adequate to resist flotation, collapse or lateral movement. Methods of anchoring may include but are not limited to the over-the-top and frame ties to ground anchors such as the following:
A. Over-the-top ties shall be provided at each of the four corners of the manufactured home, with two additional ties per side for manufactured homes less than 50 feet long requiring four additional ties per side.
B. Frame ties shall be provided at each corner of the home with five additional ties per side at intermediate points, with manufactured homes less than 50 feet long requiring four additional ties per side.
C. All components of the anchoring system shall be capable of carrying a force of 4,800 pounds.
D. Any additions to a manufactured home shall be similarly anchored This requirement is in addition to applicable State and local anchoring requirements for resisting wind forces.
(h) Storage.
(1) No materials that are buoyant, flammable, explosive, or in times of flooding could be injurious to human, animal, or plant life, shall be stored below Base Flood Elevation.
(2) Storage of other material or equipment may be allowed if not subject to major damage by floods and firmly anchored to prevent flotation or readily removable from the area within the time available after flood warning.
(i) Utility and facility requirements.
(1) All new or replacement water systems whether public or private, shall be designed to minimize or eliminate infiltration of floodwaters into the systems and discharges from the systems.
(2) All new or replacement sanitary disposal systems, whether public or private, shall be designed to minimize or eliminate infiltration of floodwaters into the systems and discharges from the systems into floodwaters.
(3) All other new or replacement public and/or private utilities and facilities shall be located and constructed to minimize or eliminate flood damage. This included locating ductwork above BFE or sealing it to prevent infiltration of floodwater.
(4) On site waste disposal systems shall be located to avoid impairment to them or contamination from them during flooding.
(j) Drainage. Adequate drainage shall be provided to reduce exposure to flood hazard.
(k) Backflow preventers. Back flow prevention valves are required to be used for all enclosed structures with sewage or drainage facilities located in the floodplain.
(1-6-04)
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