(a) Water and Wastewater Systems. The following standards shall apply to all water supply, sanitary sewerage and waste disposal systems not otherwise regulated by the Ohio Revised Code:
(1) All new and replacement water supply systems shall be designed to minimize or eliminate infiltration of flood waters into the systems;
(2) New and replacement sanitary sewerage systems shall be designed to minimize or eliminate infiltration of flood waters into the systems and discharge from the systems into flood waters; and,
(3) On-site waste disposal systems shall be located to avoid impairment to or contamination from them during flooding.
(b) Subdivisions and Large Developments.
(1) All subdivision proposals shall be consistent with the need to minimize flood damage and are subject to all applicable standards in these regulations;
(2) All subdivision proposals shall have public utilities and facilities such as sewer, gas, electrical, and water systems located and constructed to minimize flood damage;
(3) All subdivision proposals shall have adequate drainage provided to reduce exposure to flood damage;
(4) In all areas of special flood hazard where base flood elevation data are not available, the applicant shall provide a hydrologic and hydraulic engineering analysis that generates base flood elevations for all major (platted) subdivision proposals and other proposed developments at least 5 acres in size;
(6) All preliminary plans for platted subdivisions shall identify the flood hazard area and the elevation of the base flood.
(7) All final subdivision plats will provide the boundary of the special flood hazard area, the floodway boundary, and base flood elevations.
(8) In platted subdivisions, all proposed lots or parcels that will be future building sites shall have a minimum buildable area outside the natural (non-filled) 1% chance annual floodplain. The buildable area shall be large enough to accommodate primary structure and associated structures such as sheds, barns, swimming pools, detached garages, on-site sewage disposal systems, and water supply wells, if applicable.
(9) Approval shall not be given for streets within a subdivision, which would be subject to flooding. All street surfaces must be located at or above the base flood elevation.
(c) Residential Structures.
(1) New construction and substantial improvements shall be anchored to prevent flotation, collapse, or lateral movement of the structure resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy. Where a structure, including its foundation members, is elevated on fill to or above the base flood elevation, the requirements for anchoring under Section 1177.06(c)(1) of the Codified Ordinances and construction materials resistant to flood damage Section 1177.06(c)(2) of the Codified Ordinances are satisfied.
(2) New construction and substantial improvements shall be constructed with methods and materials resistant to flood damage.
(3) New construction and substantial improvements shall be constructed with electrical, heating, ventilation, plumbing and air conditioning equipment and other service facilities that are designed and/or elevated so as to prevent water from entering or accumulating within the components during conditions of flooding.
(4) New construction and substantial improvement of any residential structure, including manufactured homes, shall have the lowest floor, including basement, elevated to or above the flood protection elevation. Where flood protection elevation data are not available the structure shall have the lowest floor, including basement, elevated at least two feet above the highest adjacent natural grade. Support structures and other foundation members shall be certified by a registered professional engineer or architect as designed in accordance with ASCE 24, Flood Resistant Design and Construction.
(5) New construction and substantial improvements, including manufactured homes, that do not have basements and that are elevated to the flood protection elevation using pilings, columns, posts, or solid foundation perimeter walls with openings sufficient to allow unimpeded movement of flood waters may have an enclosure below the lowest floor provided the enclosure meets the following standards:
A. Be used only for the parking of vehicles, building access, or storage; and
B. Be designed and certified by a registered professional engineer or architect to automatically equalize hydrostatic flood forces on exterior walls by allowing for the entry and exit of floodwaters; or
C. Have a minimum of two openings on different walls having a total net area not less than one square inch for every square foot of enclosed area, and the bottom of all such openings being no higher than one foot above grade. The openings may be equipped with screens, louvers, or other coverings or devices provided that they permit the automatic entry and exit of floodwaters.
(6) Manufactured homes shall be affixed to a permanent foundation and anchored to prevent flotation, collapse or lateral movement of the structure resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy. Methods of anchoring may include, but are not limited to, use of over-the-top or frame ties to ground anchors.
(7) 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 is the minimum necessary to preserve the historic character and design of the structure, shall be exempt from the development standards of Section 1177.06(c) of the Codified Ordinances.
(8) Each new residential site shall have direct access to a public roadway or direct access to a walkway/driveway whose surface elevation is not less than the flood protection elevation and such escape route shall lead directly out of the floodplain area.
(d) Nonresidential Structures.
(1) New construction and substantial improvement of any commercial, industrial or other nonresidential structure shall meet the requirements of Section 1177.06(c)(1)-(3) and (c)(5)-(7) of the Codified Ordinances.
(2) New construction and substantial improvement of any commercial, industrial or other non-residential structure shall either have the lowest floor, including basement, elevated to or above the level of the flood protection elevation, or, together with attendant utility and sanitary facilities, shall meet all of the following standards:
A. Be dry floodproofed so that the structure is watertight with walls substantially impermeable to the passage of water to the level of the flood protection elevation;
B. Have structural components capable of resisting hydrostatic and hydrodynamic loads and effects of buoyancy; and
C. Be certified by a registered professional engineer or architect, through the use of a Federal Emergency Management Floodproofing Certificate, that the design and methods of construction are in accordance Section 1177.06(d)(2)A. and B. of the Codified Ordinances.
(3) Where flood protection elevation data are not available, the structure shall have the lowest floor, including basement, elevated at least two feet above the highest adjacent natural grade.
(4) Each new nonresidential site shall have direct access to a walkway, driveway, or roadway whose surface elevation is not less than the flood protection elevation and such escape route shall lead directly out of the floodplain area.
(e) Accessory Structures. Relief to the elevation or dry floodproofing standards may be granted for accessory structures containing no more than 600 square feet. Such structures must meet the following standards:
(1) They shall not be used for human habitation;
(2) They shall be constructed of flood resistant materials;
(3) They shall be constructed and placed on the lot to offer the minimum resistance to the flow of flood waters;
(4) They shall be firmly anchored to prevent flotation;
(5) Service facilities such as electrical and heating equipment shall be elevated or floodproofed to or above the level of the flood protection elevation; and
(6) They shall meet the opening requirements of subdivision C of Section 1177.06(c)(5) of the Codified Ordinances (this Section).
(f) Recreational Vehicles. Recreational vehicles must meet at least one of the following standards:
(1) They shall not be located on sites in special food hazard areas for more than 180 days; or
(2) They must be fully licensed and ready for highway use; or
(g) Above Ground Gas or Liquid Storage Tanks. All above ground gas or liquid storage tanks shall be anchored to prevent flotation or lateral movement resulting from hydrodynamic and hydrostatic loads.
(h) Assurance of Flood Carrying Capacity. Pursuant to the purpose and methods of reducing flood damage stated in these regulations, the following additional standards are adopted to assure that the reduction of the flood carrying capacity of watercourses is minimized:
(1) Development in Floodways.
A. In floodway areas, development shall cause no increase in flood levels during the occurrence of the base flood discharge. Prior to issuance of a floodplain development permit, the applicant must submit a hydrologic and hydraulic analysis, conducted by a registered professional engineer, demonstrating that the proposed development would not result in any increase in the base flood elevation; or
B. Development in floodway areas causing increases in the base flood elevation may be permitted provided all of the following are completed by the applicant:
1. Meet the requirements to submit technical data in Section 1177.08(i)(1) of the Codified Ordinances;
2. An evaluation of alternatives which would not result in increased base flood elevations and an explanation why these alternatives are not feasible;
3. Certification that no structures are located in areas which would be impacted by the increased base flood elevation;
4. Documentation of individual legal notices to all impacted property owners within and outside the community, explaining the impact of the proposed action on their property; and
5. Concurrence of the Village Manager of the Village of Granville and the Chief Executive Officer of any other communities impacted by the proposed actions.
(2) Development in Riverine Areas with Base Flood Elevations but No Floodways.
A. In riverine special flood hazard areas identified by FEMA where base flood elevation data are provided but no floodways have been designated, the cumulative effect of any proposed development, when combined with all other existing and anticipated development, shall not increase the base flood elevation more than 1.0 (one) foot at any point. Prior to issuance of a floodplain development permit, the applicant must submit a hydrologic and hydraulic analysis, conducted by a registered professional engineer, demonstrating that this standard has been met; or
B. Development in riverine special flood hazard areas identified by FEMA where base flood elevation data are provided but no floodways have been designated causing more than 1.0 (one) foot increase in the base flood elevation may be permitted provided all of the following are completed by the applicant:
1. An evaluation of alternatives which would result in an increase of 1.0 (one) foot or less of the base flood elevation and an explanation why these alternatives are not feasible;
(3) Alterations of a Watercourse. For the purpose of these regulations, a watercourse is altered when any change occurs within its banks. The extent of the banks shall be established by a field determination of the "bankfull stage." The field determination of "bankfull stage" shall be based on methods presented in Chapter 7 of the USDA Forest Service General Technical Report RM-245, Stream Channel Reference Sites: An Illustrated Guide to Field Technique or other applicable publication available from a Federal, State, or other authoritative source. For all proposed developments that alter a watercourse, the following standards apply:
A. The bankfull flood carrying capacity of the altered or relocated portion of the watercourse shall not be diminished. Prior to the issuance of a floodplain development permit, the applicant must submit a description of the extent to which any watercourse will be altered or relocated as a result of the proposed development, and certification by a registered professional engineer that the bankfull flood carrying capacity of the watercourse will not be diminished.
B. Adjacent communities, the U.S. Army Corps of Engineers, and the Ohio Department of Natural Resources, Division of Water, must be notified prior to any alteration or relocation of a watercourse. Evidence of such notification must be submitted to the Federal Emergency Management Agency.
C. The applicant shall be responsible for providing the necessary maintenance for the altered or relocated portion of said watercourse so that the flood carrying capacity will not be diminished. The Floodplain Administrator may require the permit holder to enter into an agreement with the Village of Granville specifying the maintenance responsibilities. If an agreement is required, it shall be made a condition of the floodplain development permit.
D. The applicant shall meet the requirements to submit technical data in Section 1177.08(i)(1)A.3. of the Codified Ordinances when an alteration of a watercourse results in the relocation or elimination of the special flood hazard area, including the placement of culverts.
(4) Compensatory Storage Required for Fill. 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 as follows: 1) on-site; or 2) on other property, as determined by a hydrologic and hydraulic analysis submitted to and approved by the Floodplain Manager and/or engineer with jurisdiction over that property.
(i) Critical Development.
(1) Critical development is that which is 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 development include jails, hospitals, schools, fire stations, service facilities, nursing homes, wastewater treatment facilities, water plants, and gas/oil/ propane storage facilities.
(2) Critical developments shall be elevated to the 500-year flood elevation or be elevated to the highest known historical flood elevation (where records are available) or two feet above the (100 year) base flood elevation, whichever is greater. If no data exists establishing the 500-year flood elevation or highest known historical flood elevation, the applicant shall provide a hydrologic and hydraulic engineering analysis that generates 500-year flood elevation data.
(j) Fill. The following standards apply to all fill activities in special flood hazard areas:
(1) Fill sites, upon which structures will be constructed or placed, must be compacted to 95 percent of the maximum density obtainable with the Standard Proctor Test method or an acceptable equivalent method.
(2) Fill slopes shall not be steeper than one foot vertical to two feet horizontal.
(3) Adequate protection against erosion and scour is provided for fill slopes. When expected velocities during the occurrence of the base flood of five feet per second armoring with stone or rock protection shall be provided. When expected velocities during the base flood are five feet per second or less protection shall be provided by covering them with vegetative cover.
(4) Fill shall be composed of clean granular or earthen material.
(k) Storage of Materials. Storage of material or equipment not otherwise prohibited in Section 1177.05 (b) shall be firmly anchored to prevent flotation.
(Ord. 02-09. Passed 3-18-09.)