§ 31-21. FP floodplain districts.
(a)
Statement of intent: The purpose of these districts is to prevent the loss of life and property, the creation of health and safety hazards, the disruption of commerce and governmental services, the extraordinary and unnecessary expenditure of public funds for flood protection and relief, and the impairment of the tax base by:
(1)
Regulating uses, activities, and development which, alone or in combination with other existing or future uses, activities, and development, will cause unacceptable increases in flood heights, velocities and frequencies.
(2)
Restricting or prohibiting certain uses, activities, and development from locating within areas subject to flooding.
(3)
Requiring all those uses, activities, and developments that do occur in flood-prone areas to be protected and/or floodproofed against flooding and flood damage.
(4)
Protecting individuals from buying lands and structures which are unsuited for intended purposes because of flood hazards.
(b)
Basis of districts:
(1)
The various floodplain districts shall include areas subject to inundation by waters of the one hundred-year flood. The basis for the delineation of these districts shall be the flood insurance study for Prince William County, Virginia and incorporated areas, including the City of Manassas Park, prepared by the Federal Emergency Management Agency Federal Insurance Administration, dated March 11, 1978.
(2)
The floodway District is delineated for purposes of this chapter using the criteria that a certain area within the floodplain must be capable of carrying the waters of the one hundred-year flood without increasing the water surface elevation of that flood more than one (1) foot at any point. These areas included in this district are specifically defined in Table No. 9 of the above referenced flood insurance study and shown on the accompanying flood boundary and floodway map or flood insurance rate map.
(3)
The floodway-fringe district shall be that area of the one hundred-year floodplain not included in the floodway district. The basis for the outermost boundary of this district shall be the one hundred-year flood elevations contained in the flood profiles of the above referenced flood insurance study and as shown on the accompanying flood boundary and floodway map or flood insurance rate map.
(4)
The approximated floodplain district shall be that floodplain area for which no detailed flood profiles or elevations are provided, but where a one hundred-year floodplain boundary has been approximated. Such areas are shown as Zone A on the maps accompanying the flood insurance study. For these areas, the one hundred-year flood elevations and floodway information from federal, state, and other acceptable sources shall be used, when available. Where the specific one hundred-year flood elevation cannot be determined for this area using other sources of data such as the U.S. Corps of Engineers floodplain information reports, the U.S. Geological Survey floodprone quadrangles, etc., then the applicant for the proposed use, development and/or activity shall determine this elevation in accordance with hydrologic and hydraulic engineering techniques. Hydrologic and hydraulic analyses shall be undertaken only by professional engineers or others of demonstrated qualifications, who shall certify that the technical methods used correctly reflect currently accepted technical concepts. Studies, analyses, computations, etc., shall be submitted in sufficient detail to allow a thorough review by the city.
(5)
The floodplain districts described above shall be overlays to the existing underlying districts as shown on the official zoning map, and as such, the provisions for the floodplain districts shall serve as a supplement to the underlying district provisions.
(6)
Where there happens to be any conflict between the provisions or requirements of any of the floodplain districts and those of any underlying district the more restrictive provisions and/or those pertaining to the floodplain districts shall apply.
(7)
In the event any provision concerning a floodplain district is declared inapplicable as a result of any legislation or administrative actions or judicial decision, the basic underlying provisions shall remain applicable.
(c)
Official zoning map:
(1)
The boundaries of the floodplain districts are established as shown on the flood boundary and floodway map and the flood insurance rate map which are declared to be a part of this chapter and which shall be kept on file at the office of the zoning administrator.
(2)
The delineation of any of the floodplain districts may be revised by the city council where natural or manmade changes have occurred and/or more detailed studies conducted or undertaken by the U.S. Army Corps of Engineers or other qualified agency or individual documents the need or possibility for such change. However, prior to any such change, approval must be obtained from the Federal Insurance Administration.
(d)
Interpretation of district boundaries: Initial interpretations of the boundaries of the floodplain districts shall be made by the zoning administrator. Should a dispute arise concerning the boundaries of any of the districts, the board of zoning appeals shall make the necessary determination. The person questioning or contesting the location of the district boundary shall be given a reasonable opportunity to present his case to the board and to submit his own technical evidence, if he so desires.
(e)
Floodplain districts generally:
(1)
Permit requirement. All uses, activities, and development occurring within any floodplain district shall be undertaken only upon approval of the required site plan and/or building permit. Such development shall be undertaken only in strict compliance with the provisions of this article and with all other applicable codes and ordinances, such as the Uniform Statewide Building Code and the City of Manassas Park subdivision ordinance. [5] Prior to the approval of a required site plan, and/or building permit, the zoning administrator shall require all applications to include compliance with all applicable state and federal laws.
(2)
Interference with floodways. Under no circumstances shall any use, activity, and/or development adversely affect the capacity of the channels or floodways of any watercourse, drainage ditch, or any other drainage facility or system.
(3)
Alteration or relocation of watercourse. Prior to any proposed alteration of any channels, or of any watercourse, stream, etc., within this jurisdiction; a permit shall be obtained from the U.S. Corps of Engineers, the Virginia Department of Environmental Quality, and the Virginia Marine Resources Commission (a joint permit application is available for any of these organizations). Furthermore, notification of the proposal shall be given by the applicant to all affected adjacent jurisdictions, the Department of Conservation and Recreation (Division of Soil and Water Conservation) and the Federal Insurance Administration.
(4)
Filling or grading in floodplains prohibited. No filling or grading, either temporary or permanent, shall be allowed within any areas (floodplains) inundated by the one hundred-year frequency flood, unless it can be demonstrated, through detailed engineering analysis that such filling or grading will have no effect on the one hundred-year frequency flood level or that satisfactory channel improvements will be made to compensate for the filling or grading such that the one hundred-year frequency flood level is not changed.
(5)
Drainage facilities. Storm drainage facilities shall be designed to convey the flow of stormwater runoff in a safe and efficient manner. The system shall insure proper drainage along streets, and provide positive drainage away from buildings. The system shall also be designed to prevent the discharge of excess runoff onto adjacent properties.
(6)
Site plans and permit applications. All applications for development in the floodplain district and all building permits issued for the floodplain shall incorporate the following information:
a.
For structures to be elevated, the elevation of the lowest floor (including basement).
b.
For structures to be floodproofed (nonresidential only), the elevation to which the structure will be floodproofed.
c.
The elevation of the one hundred-year flood.
d.
Topographic information showing existing and proposed ground elevations.
(7)
Recreational vehicles. 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; [6] or
b.
Meet the permit requirements for placement and the elevation and anchoring requirements for manufactured homes as contained in the Virginia Uniform Statewide Building Code.
(8)
Definitions.
a.
Base flood/one-hundred year flood. A flood, that, on the average, is likely to occur once every one hundred (100) years (i.e., that has a one (1) percent chance of occurring each year, although the flood may occur in any year).
b.
Base Flood Elevation (BFE). The Federal Emergency Management Agency designated one hundred-year water surface elevation, plus one (1) foot.
c.
Basement. Any area of the building having its flood subgrade (below ground level) on all sides.
d.
Board of zoning appeals. The board appointed to review appeals made by individuals with regard to decisions of the Zoning Administrator in the interpretation of his section.
e.
Development. 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 or storage of equipment or materials.
f.
Floodplain. Any land area susceptible to being inundated by water from any source.
g.
Floodway. The channel of a river or other watercourse and the adjacent land areas that must be reserved in order to discharge the base flood without cumulatively increasing the water surface elevation more than a designated height.
h.
Freeboard. A factor of safety usually expressed in feet above a flood level for purposes of floodplain management.
i.
Lowest flood. The lowest floor of the lowest enclosed area (including basement).
j.
Recreational vehicle. A vehicle which is:
1.
Built on single chassis;
2.
Four hundred (400) 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;
4.
Designed primarily not for use as a permanent dwelling but as temporary living quarters for recreational camping, travel, or seasonal use.
k.
Substantial damage. Damage of any origin sustained by a structure whereby the cost of restoring the structure to its before-damaged condition would equal or exceed fifty (50) percent of the market value of the structure before the damage occurred.
l.
Substantial improvement. Any reconstruction, rehabilitation, addition, or other improvement of a structure, the cost of which equals or exceeds fifty (50) percent of the market value of the structure before the start of construction of the improvement. This term included structures which have incurred substantial damage regardless of the actual repair work performed. The term does not, however, include either: (1) Any project for improvement of a structure to correct existing violations of state or local health, sanitary, or safety code specifications which have been identified by the local code enforcement official and which are the minimum necessary to assure safe living conditions; or (2) Any alteration of an historic structure, provided that the alteration will not preclude the structure's continued designation as an historic structure.
(f)
FW Floodway district: The Floodway District (FW) is delineated for the purpose of this article in subsection (b) of this section, "Basis of districts."
(g)
Same—Use regulations: In floodway districts:
(1)
No development shall be permitted except where the effect of such development on flood heights is fully offset by accompanying improvements which have been approved by all appropriate local and/or state authorities as required above.
(2)
No encroachments, including fill, new construction, substantial improvements, or other development shall be permitted unless it has been demonstrated through hydrologic and hydraulic analyses performed in accordance with standard engineering practices that the proposed encroachment would not result in any increase in the one hundred-year flood elevation.
(h)
Same—Permitted uses: In the floodway district, the following uses and activities are permitted, provided that they are in compliance with the provisions of the underlying district and are not prohibited by any other ordinance and provided that they do not require structures, fill, or storage of materials and equipment:
(1)
Agricultural uses, such as general farming, pasture, grazing, outdoor plant nurseries, horticulture, truck farming, forestry, sod farming, and wild crop harvesting.
(2)
Public and private recreational uses and activities, such as parks, day camps, picnic grounds, golf courses, boat launching, and swimming areas, hiking, and horseback riding trails, wildlife and nature preserves.
(3)
Accessory residential uses, such as yard areas, gardens, play areas, and pervious parking areas.
(4)
Accessory industrial and commercial uses, such as yard areas, pervious parking and loading areas, airport land strips, etc.
(i)
Same—Uses permitted by special exception: The following uses and activities may be permitted by special exception granted by the board of zoning appeals, provided that they are in compliance with the provisions of the underlying district and are not prohibited by this chapter or any other ordinance:
(1)
Structures, except for mobile homes, accessory to the uses and activities in (h) above.
(2)
Utilities and public facilities and improvements, such as railroads, streets, bridges, transmission lines, pipe lines, water and sewage treatment plants, and other similar or related uses.
(3)
Water-related uses and activities, such as marinas, docks, wharves, piers, etc.
(4)
Temporary uses, such as circuses, carnivals, and similar activities.
(5)
Storage of materials and equipment, provided that they are not buoyant, flammable or explosive, and are not subject to major damage by flooding, or provided that such material and equipment is firmly anchored to prevent flotation or movement, and/or can be readily removed from the area within the time available after flood warning.
(6)
Other similar uses and activities provided they cause no increase in flood height and/or velocities. All uses, activities, and structural developments shall be undertaken in strict compliance with the floodproofing provisions contained in all other applicable codes and ordinances.
(j)
Same—Prohibited uses: In the floodway district, the following uses and activities are prohibited:
(1)
The placement of any manufactured home, within the floodway district is specifically prohibited.
(k)
FF Flood fringe and AF approximated floodplain districts: The Flood Fringe District (FF) and Approximated Floodplain District (AF), are delineated for the purposes of this article in subsection (b) of this section, "Basis of districts."
(l)
Same—Use regulations: Flood Fringe District and Approximated Floodplain Districts:
(1)
The development and/or use of land shall be permitted in accordance with the regulations of the underlying district provided that all such uses, activities, and/or development shall be undertaken in strict compliance with the floodproofing and related provisions contained in the Virginia Uniform Statewide Building Code and all other applicable codes and ordinances.
(2)
Within the Approximated Floodplain District, proposals for all new subdivisions, manufactured home parks/subdivisions (greater than fifty (50) lots or five (5) acres, whichever is lesser), shall include base flood elevation data. The applicant shall also delineate a floodway area based on the requirement that all existing and future development not increase the one hundred-year flood elevation more than one (1) foot at any one (1) point. The engineering principal, equal reduction of conveyance, shall be used to make the determination of increased flood heights.
(3)
Within the floodway area delineated by the applicant, the provisions of subsection (g) of this section "Use regulations" shall apply.
(m)
Same—Additional factors for special exceptions and variances: In the passing upon applications for special exceptions and variances, the board of zoning appeals shall consider all relevant factors and procedures specified in other sections of this chapter and the following factors:
(1)
Applications for a special exception or variance from the provisions of this article shall be made to the board of zoning appeals, under the provisions of article VII.
(2)
The board of zoning appeals, in passing upon applications for special exceptions and variances, shall consider, in addition to those factors specified in article VII, the following:
a.
The danger to life and property due to increased flood heights or velocities caused by encroachments. No special exception or variance shall be granted for any proposed use, development, or activity within the floodway district that will cause any increase in flood levels during the one hundred-year flood.
b.
The danger that materials may be swept on to other lands or downstream to the injury of others.
c.
The proposed water supply and sanitation systems and the ability of these systems to prevent disease, contaminations, and unsanitary conditions.
d.
The susceptibility of the proposed facility and its contents to flood damage and the effect of such damage on the individual owners.
e.
The importance of the services provided by the proposed facility to the community.
f.
The requirements of the facility for a waterfront location.
g.
The availability of alternative locations not subject to flooding for the proposed use.
h.
The compatibility of the proposed use with existing development and development anticipated in the foreseeable future.
i.
The relationship of the proposed use to the comprehensive plan and floodplain management program for the area.
j.
The safety of access to the property, in time of flood, of ordinary and emergency vehicles.
k.
The expected heights, velocity, duration, rate of rise, and sediment transport of the floodwaters expected at the site.
l.
Such other factors which are relevant to the purposes of this chapter.
(3)
The board of zoning appeals may refer any application and accompanying documentation pertaining to any request for a special exception or variance to any engineer or other qualified person or agency for technical assistance in evaluating the proposed project in relation to flood heights and velocities, and the adequacy of the plans for protection and other related matters.
(4)
Special exceptions and/or variances shall only be issued after the board of zoning appeals has determined that the granting of such will not result in:
a.
Unacceptable or prohibited increases in flood heights;
b.
Additional threats to public safety;
c.
Extraordinary public expense;
d.
Create nuisances;
e.
Cause fraud or victimization of the public; or
f.
Conflict with local laws or ordinances.
(5)
Special exceptions and/or variances shall only be issued after the board of zoning appeals has determined that the special exceptions and/or variance will be the minimum reliefs to any hardship.
(6)
The board of zoning appeals shall notify the applicant for a special exception and/or variance, in writing, that the issuance of a special exception and/or variance to construct a structure below the one hundred-year flood elevation increases the risks to life and property, and will result in increased premium rates for flood insurance.
(7)
A record of the above notification as well as all variance actions, including justification for their issuance, shall be maintained and any variances which are issued shall be noted in the annual report submitted to the federal insurance administrator.
(n)
Existing structures in floodplain districts: A structure or use of a structure or premises which lawfully existed before the enactment of these provisions, but which is not in conformity with these provisions may be continued subject to the following conditions:
(1)
Existing structures and/or uses located in any floodway district shall not be expanded or enlarged, unless the effect of the proposed expansion or enlargement on flood heights is fully offset by accompanying improvements.
(2)
Any modification, alteration, repair, reconstruction, or improvement of any kind to a structure and/or use located in any floodplain district to an extent or amount of less than fifty (50) percent of its market value, shall be elevated and/or flood proofed to the greatest extent possible.
(3)
The modification, alteration, repair, reconstruction, or improvement of any kind to a structure and/or use regardless of its location in a floodplain district to an extent or amount of fifty (50) percent or more of its market value shall be undertaken only in full compliance with the provisions of the Virginia Uniform Statewide building Code. [7]
(4)
Uses or adjuncts thereof which are, or become, nuisances shall not be permitted to continue.
(o)
Municipal liability:
(1)
The degree of flood protection sought by the provisions of this chapter is considered reasonable for regulatory purposes and is based on acceptable engineering methods of study. Larger floods may occur on rare occasions. Flood heights may be increased by manmade or natural causes, such as ice jams and bridge openings restricted by debris. This chapter does not imply that areas outside the floodplain districts, or that land uses permitted within such districts, will be free from flooding or flood damages.
(2)
This chapter shall not create liability on the part of the City of Manassas Park or any officer or employee thereof for any flood damages that result from reliance on this chapter or any administrative decision lawfully made thereunder.
(Ord. No. 82-1700-192, 4-20-82)
Footnotes:--- (5) ---Cross reference— Building Code, § 7-16 et seq.; subdivision ordinance, Ch. 21.
--- (6) ---A recreational vehicle is 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 security devices, and has no permanently attached additions.
--- (7) ---Cross reference— Building Code, § 7-16 et seq.