§ 6-4012. Special standards and requirements.
A.
Standards for subdivision plats and site plans. .....Preliminary plans, development plans and final subdivision plats of all properties, all or part of which are located within any floodplain management district, must be prepared and sealed by a licensed surveyor or engineer. All proposals shall be consistent with the need to minimize flood damage. The following information, in addition to that which would otherwise be required, shall be provided on the respective plan:
1.
The one-percent annual chance flood boundary, as depicted on the FIRM and the flood hazard zone classification(s) shall be depicted on preliminary plans, development plans, and final plats.
2.
Development plans shall provide topographical information for the site at a maximum contour interval of two (2) feet, provided however that a one-foot contour interval for one (1) foot lesser and one (1) foot greater than the one-percent annual chance flood boundary shall be shown.
3.
The elevation of the finished surface of the ground at each corner of each existing building located within any flood hazard zone shall be shown on development plans and final plats.
4.
The elevation of the lowest floor including basement shall be shown on development plans for new construction or final plats of property with existing structures.
5.
For structures to be floodproofed (nonresidential only), the elevation to which the structure will be floodproofed and certified floodproofed.
6.
In "VE" zones, the elevation (in N.G.V.D.) of the bottom of the lowest horizontal structural member of the lowest floor (excluding pilings or columns).
7.
All subdivision proposals shall have adequate drainage provided to reduce exposure to flood hazards.
8.
Base flood elevation data obtained from other sources or developed using detailed methodologies, hydraulic and hydrologic analysis, comparable to those contained in the flood insurance study for subdivision developments and other proposed development proposals (including manufactured home parks and subdivisions) that exceed fifty (50) lots or five (5) acres, whichever is the lesser, shall be shown.
B.
Standards for utilities. .....All new on replacement utilities, water filtration, and wastewater treatment facilities, installed in the floodplain management district shall be designed to prevent the infiltration of floodwaters into or discharge from said utilities and constructed to minimize the potential for flood damage.
Where private waste disposal systems are to be installed or replaced, they shall be installed so that they will not be permanently contaminated or impaired by a base flood.
C.
Standards for streets and roads. .....Streets and sidewalks should be designed to minimize their potential for increasing and aggravating the levels of flood flow. Drainage openings shall be required to sufficiently discharge flood flows without unduly increasing flood height.
D.
Standards for filling of floodplain areas.
1.
Where fill within the floodplain management district is proposed, the following minimum standards shall apply:
a.
Prior to any fill, the floodway must be determined and no fill shall cause the adjacent base flood elevation to increase more than one (1) foot.
b.
Fill areas shall extend laterally a minimum of fifteen (15) feet beyond building lines from all points.
c.
Fill material shall consist only of soil and small rock materials (must pass through a three-inch opening ASTM standard sieve). Organic materials, such as tree stumps, asphalt, and rubble, shall be prohibited.
d.
Fill areas shall be graded to a finished slope of no steeper than one (1) vertical to three (3) horizontal, unless substantiated data, certified by a licensed engineer, which justifies steeper slopes, is submitted to and approved by the zoning administrator.
e.
The zoning administrator shall impose any additional standards deemed necessary to ensure the safety of the community and properties from additional flood hazard potentials caused by filling within the floodplain management district.
2.
Filling or any other encroachment into a regulatory or other designated floodway which, as determined by the zoning administrator, in any way impairs its flood conveyance shall be prohibited.
3.
Filling or any other encroachment into any channel within the floodplain management district which would, as determined by the zoning administrator, obstruct or unduly restrict water flows through said channel and, in so doing, increase the potential for flood damage, shall be prohibited whether or not such channel lies within the regulatory or other designated floodway.
4.
The filling of any portion of property solely to increase the elevation of the land to meet minimum lot area requirements and thereby create a buildable lot for residential construction within the floodplain management district shall be prohibited.
5.
These standards may be individually waived by the zoning administrator, upon the recommendation of the Isle of Wight County Wetlands Board for approved parks, recreation facilities, shoreline erosion control and beach maintenance projects where sufficient data is presented justifying the project and where it is demonstrated that such actions will not increase flood levels on any properties.
E.
Construction standards for properties in zone A [44 CFR 60.3(b)]:
1.
All new construction and substantial improvements in zone A must comply with all standards applicable to zone AE contained in this section and the floodplain construction provisions of the Virginia Uniform Statewide Building Code.
2.
For these areas in zone A, the base flood elevations and floodway information from federal, state, and other acceptable sources shall be used, when available. Where the specific one-percent annual chance flood elevation cannot be determined for this area using other sources of data, such as the U.S. Army Corps of Engineers Floodplain Information Reports, U.S. Geological Survey Flood-Prone Quadrangles, etc., then the applicant for the proposed use, development and/or activity shall determine this base flood elevation. For development proposed in the approximate floodplain the applicant must use technical methods that correctly reflect currently accepted practices, such as point on boundary, high water marks, or detailed methodologies, hydrologic and hydraulic analyses. Studies, analyses, computations, etc. shall be submitted in sufficient detail to allow a thorough review by the floodplain administrator.
3.
The floodplain administrator reserves the right to require a hydrologic and hydraulic analysis for any development. When such base flood elevation is used, the lowest floor shall be elevated to or above the base flood level plus eighteen (18) inches.
4.
During the permitting process, the floodplain administrator shall obtain:
a.
The elevation of the lowest floor (in relation to mean sea level), including the basement, of all new and substantially improved structures; and
b.
If the structure has been floodproofed in accordance with the requirements of this article, the elevation (in relation to mean sea level) to which the structure has been floodproofed.
5.
Base flood elevation data shall be obtained from other sources or developed using detailed methodologies comparable to those contained in a FIS for subdivision proposals and other proposed development proposals (including manufactured home parks and subdivisions) that exceed fifty (50) lots or five (5) acres, whichever is the lesser.
F.
Construction standards for properties in zone AE. .....Until a regulatory floodway is designated, no new construction, substantial improvements, or other development (including fill) shall be permitted with the areas of special flood hazard, designated as zones AE on the 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 (1) foot at any point within Isle of Wight County. In addition, the following provisions shall apply [44 CFR 60.3(c)]:
1.
All new and replacement electrical equipment, and heating, ventilating, air conditioning and other service facilities shall be installed at least one and one-half (1½) feet above the base flood elevation or otherwise designed and located so as to prevent water from entering or accumulating within the components during conditions of flooding.
2.
All electrical distribution panels shall be installed at least three (3) feet above the base flood elevation or otherwise designed and located so as to prevent inundation.
3.
In all cases, elevation of the lowest floor of the structure, including basements, to at least one and one-half (1½) feet above the base flood elevation or, in the case of nonresidential structures, floodproofing to at least that level. All new and substantially improved structures shall be constructed according to the VA USBC, and anchored to prevent flotation, collapse or lateral movement of the structure. The lowest floor elevation of any new residential structure, including basements, constructed within a floodplain area shall be at least one and one-half (1½) feet above base flood elevation. The lowest floor elevation of any new nonresidential structure constructed within a floodplain area shall be at least one (1) foot above base flood elevation, unless such structure is floodproofed. In addition, no existing structure shall be modified, expanded or enlarged unless the new construction complies with this standard.
4.
Manufactured homes that are placed or substantially improved on sites shall be elevated on a permanent foundation such that the lowest floor of the manufactured home is elevated a least one and one-half (1½) feet above base flood level and be securely anchored to an adequately anchored foundation system to resist floatation, collapse and lateral movement.
5.
Recreational vehicles placed on sites shall either:
a.
Be on the site for fewer than one hundred eighty (180) consecutive days, be fully licensed and 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 has no permanently attached additions; or meet the permit requirements for placement and the elevation and anchoring requirements for manufactured homes in subsection F.4. of this section.
6.
New construction and substantial improvements shall be constructed with materials and utility equipment resistant to flood damage.
7.
New construction and substantial improvements shall be constructed by methods and practices that minimize flood damage.
8.
New development shall not be permitted unless it is demonstrated that the cumulative effect of all past and projected development will not increase the base flood elevation by more than one (1) foot.
9.
For floodproofed nonresidential structures, a licensed professional engineer or architect must certify the structure has been floodproofed.
10.
Where base flood elevation data has been utilized and obtained, as required by this ordinance, the floodplain administrator shall obtain, record, and maintain the actual finished construction elevations of the lowest floor and floodproofing elevations. This information shall be recorded on a current FEMA Elevation Certificate signed and sealed by a professional licensed land surveyor.
11.
Fully enclosed areas of new construction or substantially improved structures, which are below regulatory flood protection elevation shall:
a.
Not be designed or used for human habitation, but shall only be used for parking of vehicles, building access or limited storage of maintenance equipment used in connection with the premises. Access to the enclosed area shall be the minimum necessary to allow for parking of vehicles (garage door) or limited storage of maintenance equipment (standard exterior door), or entry to the living area (stairway or elevator);
b.
Be constructed entirely of flood-resistant materials below the regulatory floor protection elevation;
c.
Include measures to automatically equalize hydrostatic flood forces on walls by allowing for the entry and exit of floodwaters. To meet this requirement, the openings must either be certified by a professional engineer or architect or meet the following minimum design criteria:
i.
Provide a minimum of two (2) openings on different sides of each enclosed area subject to flooding.
ii.
The total net area of all openings must be at least one (1) square inch for each square foot of enclosed area subject to flooding.
iii.
If a building has more than one (1) enclosed area, each area must have openings to allow floodwater to automatically enter and exit.
iv.
The bottom of all required openings shall be no higher than one (1) foot above the adjacent grade.
v.
Openings may be equipped with screens, louvers, or other opening coverings or devices, provided they permit the automatic flow of floodwaters in both directions.
vi.
Foundation enclosures made of flexible skirting are not considered enclosures for regulatory purposes, and, therefore, do not require openings. Masonry or wood underpinning, regardless of structural status, is considered an enclosure and requires openings as outlined above.
12.
Development activities in zone AE on the Isle of Wight County FIRMs which increase the water surface elevation of the base flood by more than one (1) foot may be allowed, provided that the applicant first applies - with Isle of Wight County's endorsement - for a conditional letter of map revision and receives the approval of the Federal Emergency Management Agency.
G.
Construction standards for properties in coastal A zones. .....All new construction and substantial improvements in coastal A zones of the floodplain management area shall comply with the provisions of the AE zone as set forth in section 6-4012.F. In addition, buildings and structures within this zone shall have the lowest floor elevated to or above the base flood elevation plus eighteen (18) inches of freeboard.
H.
Construction standards for properties in coastal high hazard area. .....All new construction and substantial improvements in the V-zones of the floodplain management area shall occur in accordance with the applicable floodplain construction provisions contained in the Virginia Uniform Statewide Building Code. The zoning administrator shall satisfy himself that all applicable provisions have been complied with prior to issuing building permits or temporary or permanent certificates of occupancy. In addition, the following standards shall apply [44 CFR 60.3(e)]:
1.
All new construction shall be located landward of the reach of mean high tide.
2.
There shall be no fill used as structural support.
3.
There shall be no alteration of sand dunes, watercourses or banks, which would increase potential flood damage.
4.
Within V-zones on the flood insurance rate map, obtain the elevation (in relation to mean sea level) of the bottom of the lowest horizontal structural member of the lowest floor (excluding pilings and columns) of all new and substantially improved structures.
5.
All new construction and substantial improvements elevated on pilings and columns must have the bottom of the lowest horizontal structural member of the lowest floor (excluding the pilings or columns) elevated at least one and one-half (1½) feet above the base flood level and the pile or column foundation and structure attached thereto must be anchored to resist flotation, collapse and lateral movement due to the effects of wind and water loads acting simultaneously on all building components. Water-loading values used shall be those associated with the base flood. Wind-loading values used shall be those required by applicable state or local building standards. A registered professional engineer or architect shall develop or review the structural design and methods of construction and shall certify that design and methods of construction to be used are in accordance with accepted standards.
6.
Provide that all new construction and substantial improvements, within zones VE, V1-30 and V on the community's FIRM, have the space below the lowest floor either free of obstruction or constructed with non-supporting breakaway walls, open wood lattice-work, or insect screening intended to collapse under wind and water loads without causing collapse, displacement, or other structural damage to the elevated portion of the building or supporting foundation system. For the purpose of this section, a breakaway wall shall have a design safe-loading resistance of not less than ten (10) and no more than twenty (20) pounds per square foot. Use of breakaway walls which exceed a design safe-loading resistance of twenty (20) pounds per square foot (either by design or when so required by local or state codes) may be permitted only if a registered professional engineer or architect certifies that the designs proposed meet the following conditions:
a.
The elevated portion of the building and supporting foundation system shall not be subject to collapse, displacement, or other structural damage due to the effects of wind and water loads acting simultaneously on all building components (structural and nonstructural). Water-loading values used shall be those associated with the base flood.
b.
Wind-loading values used shall be those required by applicable state or local building standards. Such enclosed space shall be usable solely for parking of vehicles, building access or storage.
7.
All recreational vehicles placed in V-zones shall be:
a.
On site for fewer than one hundred eighty (180) consecutive days; and
b.
Be fully licensed and ready for highway use; or
c.
Meet the same standards as for conventional housing in V-zones.
8.
All new and replacement electrical equipment, and heating, ventilating, air conditioning and other service facilities shall be installed at least three (3) feet above the base flood elevation or otherwise designed and located so as to prevent water from entering or accumulating within the system.
9.
All electrical distribution panels shall be installed at least three (3) feet above the base flood elevation or otherwise located so as to prevent inundation.
10.
In all cases, elevation of the lowest horizontal structural member of the lowest floor of the structure, excluding pilings or columns, to at least one and one-half (1½) feet above the base flood elevation and may result in a reduction of flood insurance premiums.
11.
Manufactured homes that are placed or substantially improved on sites shall meet the same standards as conventional housing in V-zones. (11-19-15; 7-19-18.)