Williston City Zoning Code
SECTION 7
F-H: Flood Hazard Overlay District.
[Ord. No. 613, Ord. No. 703, Ord. No. 716, Ord. No. 850; Ord. No. 1092]
A.
Intent. This district is intended to be an overlay district and includes lands subject to a 1% or greater chance of flooding in any given year. These lands (known as special flood hazard areas) include, but are not limited to, those identified by the Federal Emergency Management Agency in a scientific and engineering report entitled "The Flood Insurance Study for the City of Williston, dated August 5, 2010," with an accompanying Flood Insurance Rate Map and all subsequent revisions thereto. This map is hereby adopted by reference and declared to be a part of this ordinance. It is intended to discourage unwise and incompatible development in special flood hazard areas so as to protect the natural environment and to prevent loss of life and property due to flooding.
B.
Permitted uses. Uses permitted in this district shall be restricted to those conforming with allowable uses in the underlying districts and to those which meet the regulations of this section.
C.
Permit procedures. Before development begins within any special flood hazard area, a permit shall be obtained from the City Building Official. The permit shall specifically include:
1.
Elevation in relation to mean sea level, of the lowest floor (including basement) of all proposed structures.
2.
Elevation in relation to mean sea level to which any structure will be floodproofed.
3.
Certification by a registered professional engineer or architect that the floodproofing methods for any non-residential structure meet the floodproofing criteria in the Specific Standards Subsection G.2.
4.
Description of the extent to which any watercourse will be altered or relocated as a result of proposed development.
D.
Use of other base flood data. When base flood elevation data has not been provided for the City of Williston and its extra-territorial jurisdiction, the Building Official shall coordinate with the City Engineer to obtain, review, and reasonable utilize any base flood elevation and floodway data available from a Federal, State, or other source, in order to administer the provisions of this ordinance.
E.
Review procedures. All permit applications shall be reviewed (using the best available base flood elevation data from any Federal, State, or local source) to: assure sites are reasonably safe from flooding; determine that all necessary permits have been obtained from those Federal State, or local agencies from which prior approval is required; and to determine if the proposed development adversely affects the flood-carrying capacity of a flood-prone area. For the purposes of this ordinance, "adversely affects" means 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 foot at any time.
1.
If it is determined that there is not an adverse effect and the development is not subject to other provisions of this ordinance, then the permit shall be granted without further considerations.
2.
If it is determined that there is an adverse effect, then technical justification (i.e., a registered professional engineer) for the proposed development shall be required.
3.
If it is determined there is no adverse effect, then the following provisions shall apply.
F.
General standards. All new development and substantial improvements including the placement of prefabricated buildings and mobile homes (manufactured homes) shall conform to the following standards:
1.
All new construction and substantial improvements (including additions) shall be anchored to prevent flotation, collapse, or lateral movement of the structure.
2.
All mobile homes (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.
3.
All new construction and substantial improvements shall be constructed with materials and utility equipment resistant to flood damage.
4.
All 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 located so as to prevent water from entering or accumulating within the components during conditions of flooding.
5.
All new and replacement water supply systems shall be designed to minimize or eliminate infiltration of flood waters into the system.
6.
New and replacement sanitary sewage systems shall be designed to minimize or eliminate infiltration of flood waters into the systems and discharge from the systems into flood waters.
7.
On-site waste disposal systems shall be located to avoid impairment to them or contamination from them during flooding.
8.
All subdivision proposals shall be consistent with the need to minimize flood damage; shall have public utilities and facilities such as sewer, gas, electrical, and water systems located and constructed to minimize flood damage; and shall have adequate drainage provided to reduce exposure to flood damage.
9.
Base flood elevation data shall be provided for subdivision proposals and other proposed developments which contain at least 50 lots or five acres (whichever is less).
10.
Encroachments, including fill, new construction, substantial improvements, and other development shall be prohibited in any floodway unless a technical evaluation demonstrates that the encroachments will not result in any increase in flood levels during the occurrence of the flood discharge.
G.
Specific standards. Where base flood elevation data is available, the following standards shall be met.
1.
Residential construction.
a.
New construction and substantial improvement of any residential structure shall have the lowest floor, including basement, elevated to or above base flood elevation.
b.
Mobile homes (manufactured homes) shall be placed so that the lowest floor is elevated on fill to or above the base flood elevation.
2.
Nonresidential construction. New construction and substantial improvement of any commercial, industrial or other nonresidential structure shall either have the lowest floor, including basement, elevated to the level of the base flood elevation; or, together with attendant utility and sanitary facilities, shall:
a.
Be floodproofed so that below the base flood level the structure is watertight with walls substantially impermeable to the passage of water. A registered professional engineer or architect shall develop and/or review structural design, specifications, and plans for the construction, and shall certify that the design methods of construction are in accordance with accepted standards of practice.
b.
Have structural components capable of resisting hydrostatic and hydrodynamic loads and effects of buoyancy.
c.
Be certified by a registered professional engineer or architect that the standards of this subsection are satisfied. Such certification shall be provided to the City Building Official as set forth in the Administrative Requirements Subsection H.2.b.
H.
Administrative requirements. In all special flood hazard area, the City Building Official shall:
1.
Obtain and record the actual elevation (in relation to mean sea level) of the lowest habitable floor (including basement) of all new or substantially improved structures, and whether or not the structure contains a basement.
3.
Maintain for public inspection all records pertaining to the provisions of this ordinance.
4.
Notify nearby communities, water resource districts and the North Dakota State Engineer, as necessary, prior to any alteration or relocation of a watercourse, and submit evidence of such notification to the Federal Management Agency; and
5.
Require that maintenance is provided within the altered or relocated portion of said watercourse so that the flood carrying capacity is not diminished.