Sec. 48-432. - Supplemental building zone map-flood districts.
Sec. 48-436. - Requirements for zoning board of adjustment approval.
The following words, terms and phrases, when used in this division, shall have the meanings ascribed to them in this section, except where the context clearly indicates a different meaning:
Base flood means the flood having a one percent chance of being equalled or exceeded in any given year; sometimes called 100-year flood.
Base flood elevation or base flood level means the height in feet above a known reference level of the water surface of the base flood, as determined by the federal insurance administrator under the National Flood Insurance Program, based upon the Type 15 Flood Insurance Study for the City of Wilmington, Delaware, including the profiles and flood surface elevations contained therein; or where such determination and study has not been made, as determined by the zoning administrator based upon an engineering study certified by a registered professional engineer and submitted as part of an applicant's application for approval of a use.
Coastal flood hazard area means the area subject to tidal flooding accompanied by high velocity waters, including wind-propelled wave wash, based upon the Type 15 Flood Insurance Study for the City of Wilmington, Delaware.
Development means any man-made change to improved or unimproved real estate, including, but not limited to buildings or other structures, mining, dredging, filling, grating, paving, excavation or drilling operations or storage of equipment or materials.
Flood or flooding means:
(1)
A general and temporary condition in which normally dry land areas are covered by either:
a.
The overflow of inland or tidal waters;
b.
The unusual and rapid accumulation or run-off of surface waters from any source; or
c.
Mudslides resulting from accumulations of water on or under the ground.
(2)
The collapse or subsidence of land along a shoreline resulting from erosion or undermining caused by waves or currents of water exceeding anticipated cyclical levels, or suddenly caused by an unusually high water level accompanied by a severe storm or other unforseen natural force or event.
Floodplain means the land area subject to a probability of flooding at least once in 100 years.
Floodway means the channel of a stream and that portion of the adjacent floodplain that must be kept free of encroachments in order that the base flow may be carried without increasing the water surface level of the base flood more than one foot at any point. See F-1, regulatory floodway district.
Floodway fringe means the area between the floodway and the limits of the base flood; the portion of the floodplain that could be completely obstructed without increasing the water surface level of the base flood more than one foot at any point.
Historic structure means any structure that is:
(1)
Listed individually in the National Register of Historic Places (a listing maintained by the U.S. Department of Interior) or preliminarily determined by the secretary of the interior as meeting the requirements for individual listing on the National Register.
(2)
Certified or preliminarily determined by the secretary of the interior as contributing to the historical significance of a registered historic district or a district preliminarily determined by the secretary to qualify as a registered historic district.
(3)
Individually listed on a state inventory of historic places in states with historic preservation programs, which have been approved by the secretary of the interior; or
(4)
Individually listed on a local inventory of historic places in communities with historic preservation programs that have been certified either:
a.
By an approved state program as determined by the secretary of the interior; or
b.
Directly by the secretary of the interior in states without approved programs.
Lowest floor means the lowest floor of the lowest enclosed area (including basement). An unfinished or flood resistant enclosure, useable solely for parking of vehicles, building access or storage in an area other than a basement area is not considered a building's lowest floor; provided that such enclosure is not built so as to render the structure in violation of the applicable non-elevation design requirements of this Code.
Recreational vehicle means a vehicle which is:
(1)
Built on a single-chassis;
(2)
Four hundred square feet or less when measured at the largest horizontal projection;
(3)
Designed to be self-propelled or permanently towable by a light duty truck; and
(4)
Designed primarily not for use as a permanent dwelling, but as temporary living quarters for recreational, camping, travel or seasonal use.
Substantial damage means damage of any origin sustained by a structure, whereby the cost of restoring the structure to its before damaged condition would equal or exceed 50 percent of the market value of the structure before the damage occurred.
Substantial improvement means any repair, reconstruction or improvement of a structure, the cost of which equals or exceeds 50 percent of the market value of the structure either before the improvement or repair is started, or if the structure has been damaged and is being restored, before the damage occurred. For the purposes of this definition, "substantial improvement" is considered to occur when the first alteration of any wall, ceiling, floor or other structural part of the building commences, whether or not that alteration affects the external dimensions of the structure. The term does not, however, include either any project for improvement of a structure to comply with existing state or local health, sanitary or safety code specifications which are solely necessary to assure safe living conditions or any alteration of a structure listed on the National Register of Historic Places.
(Code 1968, § 48-50.1; Ord. No. 96-074, § 1, 12-19-96)
Cross reference— Definitions and rules of construction generally, § 1-2.
Sec. 48-432. - Supplemental building zone map-flood districts.
(a)
The various flood districts are as shown, defined and bounded on the Supplemental Building Zone Map-Flood Districts, dated April 17, 1996, referred to in this chapter as the flood zone map, and are on file in the office of the zoning administrator in the department of licenses and inspections. This map is based upon the 100-year flood as delineated in the flood insurance study prepared by the Federal Emergency Management Agency; any changes to this data must be approved by the federal insurance administrator.
(b)
Such map and all explanatory matter thereon are hereby declared to be a part of this chapter, and shall be interpreted in the same manner as the zoning map. The districts so designated and the use and other regulations applicable to them are in addition to all other regulations applicable under this chapter.
(c)
For purposes of this Code, the identified floodplain area shall be those areas of the city which are subject to the 100-year flood as shown on the floodway map or flood insurance rate map (FIRM) and described in the flood insurance study (FIS) prepared for the city by the Federal Emergency Management Agency (FEMA), dated April 17, 1996, or the most recent revision thereof.
(d)
The granting of a permit or approval of a subdivision or development plan in any identified flood-prone area, shall not constitute a representation, guarantee or warranty of any kind by the city, or by any official or employee thereof of the practicability or safety of the proposed use, and shall create no liability upon the part of the city.
(Code 1968, § 48-50.2; Ord. No. 91-080, § 1, 12-19-91; Ord. No. 96-074, § 1, 12-19-96)
(a)
Purpose. The F-1 district, watercourse channels and floodways, is designed to protect watercourse channels and the adjacent floodway and to preserve the capacity of the floodway to discharge the base flood without substantial increase in the water surface elevation of the base flood.
(b)
Uses permitted under zoning board of adjustment approval. The following uses are permitted in an F-1 district under zoning board of adjustment approval, subject to the requirements of section 48-435
(1)
Agriculture.
(2)
Recreation not requiring structures for human habitation.
(3)
Privately owned open space.
(4)
Dams, bulkheads, docks and similar water-related structures.
(5)
Streets, railroads, bridges, pipelines, electrical lines.
(6)
The development of property for any use that is otherwise permitted by the provisions of this chapter applicable to the underlying zoning district classification for which the F-1 classification is an overlay, subject to the applicable requirements of section 48-551 and to the following:
a.
The owner or agent for the owner of the subject property provides a detailed physiographic and hydrologic study prepared by a registered professional engineer certifying that the proposed development will not result in any increase in flood levels within the city during the occurrence of the base flood discharge;
b.
Each such study shall be submitted to the zoning administrator not less than 60 days prior to the scheduled review by the zoning board of adjustment;
c.
The proposed development will not endanger the safety and welfare of its occupants or the general public; and
d.
The proposed development will not endanger the quality or quantity of the city's water source.
In addition to such requirements, the engineer's study required by this subsection shall also be forwarded by the developer or agent for the developer to engineers of the Federal Emergency Management Agency for review and approval by the same.
(Code 1968, § 48-50.3)
(a)
Purpose. The F-2 district, floodway fringes and approximate floodplain, is designed to encourage appropriate development within floodway fringe and approximated floodplain areas while minimizing flood damage resulting from either increased flood elevations or inadequate design or construction.
(b)
Uses permitted under zoning board of adjustment approval. All uses permitted under other provisions of this chapter are permitted in an F-2 district under zoning board of adjustment approval, subject to the requirements of section 48-551.
(Code 1968, § 48-50.4)
(a)
Purpose. The F-3 district, coastal flood hazard areas, is designed to encourage appropriate use or development in areas subject to flooding from tidal waters, while minimizing risk of loss or damage.
(b)
Uses permitted under zoning board of adjustment approval. All uses permitted under other provisions of this chapter are permitted in an F-3 district, under zoning board of adjustment approval, subject to the provisions of section 48-435
(Code 1968, § 48-50.5)
Sec. 48-436. - Requirements for zoning board of adjustment approval.
(a)
Generally. Within the various floodplain districts, F-1, F-2 and F-3, a use may be approved only if:
(1)
All necessary permits have been received from those governmental agencies from which approval is required by federal or state law, including section 404 of the Federal Water Pollution Control Act Amendments of 1972, 33 USC, 1334.
(2)
All proposed new development is consistent with the need to minimize flood damage; all public utilities and facilities, such as sewer, gas, electrical and water systems will be located and constructed to minimize or eliminate flood damage; and adequate drainage is provided to reduce exposure to flood hazards.
(3)
New and replacement water supply systems are designed to minimize or eliminate infiltration of floodwaters into the systems.
(4)
New and replacement sanitary sewer systems are designed to minimize or eliminate infiltration of floodwaters into the systems and discharges from the systems into floodwaters.
(5)
Before approving any alteration or relocation of a watercourse in a riverine situation, the zoning administrator shall notify, through the building official, adjacent communities and the state office designated by the governor to assist in implementation of the National Flood Insurance Program and submit copies of such notifications to the federal flood insurance administrator. In such cases, the flood-carrying capacity of the altered or relocated watercourse must be assured.
(b)
Within districts F-1 and F-2. Within the regulatory floodway (F-1) and within the floodway fringe and approximated floodplain (F-2), comprising districts F-1 and F-2, any use for which an alteration to the existing grade, or the erection, installation or substantial improvement is proposed or required, may be approved only if, in addition to the requirements of subsection (a) of this section:
(1)
All new construction and substantial improvements of residential structures will have the lowest floor, including basement, elevated to one foot above the base flood level.
(2)
All new construction and substantial improvements of nonresidential structures will have the lowest floor, including basement, elevated to one foot above the base flood level, or be so designed to meet the standards of the building code for floodproofing of structures.
(3)
A detailed development plan, showing existing and proposed topography and location, area and bulk of existing and proposed structures, has been submitted to the board.
(4)
Every structure for residential or commercial use is set back at least ten feet from the boundary of any stream, bank or floodway boundary.
(5)
Approval of the use is conditional upon development in accordance with the development plan.
(c)
Within district F-1. Within the F-1 district, floodways, a use that requires or proposes any structure, other than a water control or water supply structure, may be approved only if every part of the structure except piers, pilings or similar supporting members is located above the base flood elevation, and no increase in flood levels will occur during the base flood discharge. No variance or special exceptions shall be granted for any development in the floodway that will result in any increase in flood levels within the city during the occurrence of the base flood. As used in this section, "development" means any manmade change to improved or unimproved real estate, including but not limited to buildings or other structures, mining, dredging, filling, grading, paving, excavation or drilling operations.
(d)
Within district F-2. Within the F-2 district, if the base flood elevation has not been determined, a use may be approved only if:
(1)
A registered professional engineer has provided to the board a certification, based upon a detailed hydraulic and hydrologic study that the effect of the proposed use, 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 point within the city.
(e)
Within district F-3. Within the F-3 district the coastal flood hazard area, a use may be approved only if:
(1)
All new construction is located landward of the reach of mean high tide.
(2)
All new construction and substantial improvements meet the requirements of the building code for construction within coastal flood hazard areas.
(Code 1968, § 48-50.6; Ord. No. 91-080, § 1, 12-19-91)
FOOTNOTE(S):
(145) Cross reference— Sediment and stormwater management, § 11-36 et seq. (Back)