In order to prevent excessive flood damage and to allow for the protection of the natural and beneficial floodplain functions, the following provisions shall apply to all development, new construction and substantial improvements to existing structures in all floodplain zones. In the event that a structure is in more than one (1) zone, the more stringent provision shall apply to the entire structure.
In all floodplain zones, any development which proposes to alter a watercourse shall obtain a variance. All conditions for encroachment in the floodway shall be met and adverse impacts to aquatic resources shall be minimized. Adjacent communities and property owners, FEMA and the Maryland Water Resources Administration shall be notified by the applicant prior to any modification of a watercourse. The Water Resources Administration of the Department of Natural Resources may require a waterway construction permit.
A. 
General development shall not occur in the floodplain where alternative locations exist. Before a permit is issued, the applicant shall demonstrate that new structures cannot be located out of the floodplain and that encroachments onto the floodplain are minimized.
B. 
Elevation requirements, residential structures.
(1) 
The elevation of the lowest floor of all new or substantially improved structures, including manufactured homes, shall be elevated to or above one (1) foot above the elevation of the one-hundred-year flood. In nontidal floodplains, horizontal expansions which increase the footprint and that are less than substantial shall also have the lowest floor elevated to or above the flood protection elevation. A registered surveyor or professional engineer shall certify elevation of the lowest floor on the elevation certificate after the lowest floor is in place.
(2) 
Basements are prohibited. Enclosures below the flood protection elevation shall be constructed with water-equalizing vents to meet the specification found in § 182-12B of this chapter.
(3) 
Improvements in tidal floodplains which are less than substantial shall be constructed to minimize damage during flooding or shall be elevated to the greatest extent possible.
C. 
Elevation requirements, nonresidential structures. All new or substantially improved nonresidential structures shall either be elevated as required for residential structures or shall be floodproofed. Horizontal expansions in the nontidal floodplain which increase the footprint and which are less than substantial shall also have the lowest floor elevated to one (1) foot above the flood protection elevation. In nontidal floodplains, basements and floodproofing are prohibited. Floodproofing designs must ensure that areas below the flood protection elevation are watertight with walls substantially impermeable to the passage of water and with structural components capable of resisting hydrostatic and hydrodynamic loads and effects of buoyancy. When the floodproofing option is chosen, a floodproofing certificate must be completed by a registered professional engineer or architect.
D. 
Fill.
(1) 
The placement of more than six hundred (600) cubic yards of fill per parcel in the floodplain is prohibited. Elevating buildings by other methods shall be considered unless six hundred (600) cubic yards of fill or less is required. An applicant shall demonstrate that fill is the only alternative to raising the structure and that the fill will not affect the flood storage capacity or increase flooding onto neighboring properties.
(2) 
In the event that structures on adjacent properties are known or determined to be subject to flooding under current conditions, the planning office may require submission of hydrologic and hydraulic analysis of the effects of the proposed fill. All fill shall meet the standards set forth in § 182-13E of this chapter.
E. 
Subdivisions.
(1) 
Nontidal floodplains. To avoid flood damage and to protect the natural and beneficial floodplain functions, new flood-prone building sites shall not be permitted in nontidal floodplains. Each new lot shall have a suitable building site outside the floodplain. Whenever possible, development should be located outside the floodplain. An access road constructed above the elevation of the one-hundred-year floodplain shall be provided.
(2) 
Tidal floodplains. New subdivisions in tidal floodplains shall be designed to develop land outside the floodplain whenever possible. An access road constructed above the elevation of the one-hundred-year flood shall be provided whenever possible.
A. 
General. Floodways shall be preserved to carry the discharge of the one-hundred-year flood. Floodways present increased risks to human life and property because of their relatively faster and deeper flowing waters.
(1) 
Fill shall not be permitted.
(2) 
New structures shall not be permitted.
(3) 
New development shall not be permitted where alternatives exist elsewhere or if any increase in the water surface elevations of the one-hundred-year flood will occur.
(4) 
A development in the floodway which may result in any increase in water surface elevations or change to the floodway shall be submitted to FEMA for a conditional letter of map revision. Hydrologic and hydraulic analysis on existing floodway models performed in accordance with standard engineering practices and certified by a registered professional engineer must be submitted. Failure to receive this permit shall be grounds for denial of the permit.
B. 
Alternative analysis requirement. An alternative analysis shall be submitted to the Planning Office before a permit shall be issued. The alternative analysis shall demonstrate that:
(1) 
No reasonable alternative exists outside the floodway.
(2) 
Encroachment in the floodway is the minimum necessary.
(3) 
The development will withstand the one-hundred-year flood without significant damage.
(4) 
The development will not increase downstream or upstream flooding or erosion.
C. 
Existing structures. Existing structures in the floodway shall be substantially improved only by variance and if they can be brought into conformance with this chapter without increasing the footprint. Minor additions (less than substantial) must be elevated to the flood protection elevation on pilings or columns. In the event of substantial damage or replacement, the applicant shall submit an alternative analysis to determine if the structure can be relocated to a less hazardous site. Where replacement structures cannot be relocated, they shall be limited to the footprint of the previous structure and must comply with the elevation requirements of this chapter. Permits for incremental improvements and additions shall be tracked by the Planning Office and, if cumulative improvements constitute substantial improvement, no further permits may be issued unless the structure conforms to the provisions of this chapter.
D. 
Maintenance of natural channel. The natural watercourse shall be maintained for protection of aquatic resources. A variance is required for alteration of watercourses. Any variance issued must assure that the conditions for encroachment in the floodway are met, adverse impacts to aquatic resources are minimized and the public good outweighs the adverse impacts. The provisions of § 182-8, pertaining to altering a watercourse, shall be met.
E. 
Obstructions. Structures or fill which may impede, retard or change the direction of the flow of floodwaters or any materials that may be carried downstream to cause damage shall not be placed in the floodway. Fences, except two (2) wire fences, shall not be placed in the floodway.
A. 
New development shall not be permitted in the coastal high hazard area where the action of wind and waves, in addition to tidal flooding, is a factor unless the applicant demonstrates that:
(1) 
No reasonable alternative exists outside the coastal high hazard area.
(2) 
The encroachment into the coastal high hazard area is the minimum necessary.
(3) 
The development will withstand the one-hundred-year wind and water loads without damage.
(4) 
The development will not create an additional hazard to existing structures.
(5) 
Any natural dune system will not be disturbed.
B. 
New and substantially improved structures.
(1) 
All new or substantially improved structures shall be elevated on adequately anchored pilings or columns to resist flotation, collapse and lateral movement due to the effect of the one-hundred-year water loads and wind loads acting simultaneously on all building components. Water-loading values shall be those associated with the base flood and wind-loading values shall be those required by local building standards. The bottom of the lowest horizontal structural member supporting the lowest floor shall be elevated one (1) foot above the base flood elevation. Building designs and elevations must be certified by a registered professional engineer or architect that the building has been designed to withstand the water and wind loads and to be anchored properly. The use of slabs or other at-grade foundation systems shall be prohibited.
(2) 
The space below the flood protection elevation shall be free of obstruction or may be enclosed with open wood lattice, insert screening or breakaway walls.
(3) 
Breakaway walls shall be designed to collapse under a wind and water load less than would occur during the one-hundred-year flood and have a design safe loading resistance of not less than ten (10) pounds and not more than twenty (20) pounds per square foot. Glass walls shall not be considered breakaway walls. Enclosed areas below the flood protection elevation shall be used solely for the parking of vehicles, limited storage and building access. If such areas are enclosed, a nonconversion agreement shall be signed.
C. 
Manufactured homes and recreational vehicles. Manufactured homes shall not be permitted in the coastal high hazard area. Recreational vehicles shall meet the requirements of § 182-10 of this chapter.
D. 
Fill and excavation. Fill shall not be used for the structural support of buildings. Excavation under existing structures or excavation within any enclosed space shall be prohibited.
E. 
Location of structures. New construction within the reach of mean high tide is prohibited. Alteration of the dune system is prohibited.
F. 
Existing structures. Existing structures shall not be substantially improved or expanded vertically or horizontally unless the entire foundation system is certified by a professional engineer or architect as capable of supporting the existing building and the proposed improvement during the one-hundred-year storm as specified in § 182-11B. Permits for incremental improvements shall be tracked and, when cumulative improvements constitute substantial improvement, the entire building shall comply with § 182-11B.
In addition to the regulations found in §§ 182-7 through 194-11, the following specific standards shall be applied:
A. 
Placement of building and materials. In general, buildings and accessory structures should be located entirely out of the floodplain, out of the flood protection setback or on land that is least susceptible to flooding. All structures permitted in the floodplain shall be oriented so as to offer the least resistance to the flow of floodwaters. Materials which are buoyant, flammable, explosive, hazardous to health or which at times of flooding may be injurious to human, animal or plant life shall not be stored below the flood protection elevation.
B. 
Enclosures below lowest floor. Buildings which have been elevated and have fully enclosed areas below the flood protection elevation, as well as garages and accessory structures which are not elevated, shall be constructed with water-equalizing vents which meet or exceed the following standards:
(1) 
A minimum of two (2) openings on different walls having a total net area of not less than one (1) square inch for every square foot of enclosed area subject to flooding shall be provided.
(2) 
The bottom of all openings shall be no higher than one (1) foot above grade.
(3) 
Openings may be equipped with screens, louvers, valves or other coverings or devices, provided that they permit the automatic entry and exit of floodwaters to equalize hydrostatic forces on the walls.
(4) 
Fully enclosed areas below the flood protection elevation shall be used solely for parking of vehicles, access to the building or storage. If such areas are enclosed, a nonconversion agreement shall be signed by the applicant.
(5) 
In coastal high hazard areas, enclosures below the flood protection elevation shall comply with the provisions of § 182-11 of this chapter.
C. 
Manufactured homes and manufactured home parks.
(1) 
New manufactured homes and manufactured home parks shall be prohibited in the coastal high hazard area and in the floodway. In other floodplain zones, all new, replacement or substantially improved manufactured homes, whether in a manufactured home park or not, shall comply with § 182-9B of this chapter.
(2) 
Methods of anchoring shall include use of over the top and frame ties to ground anchors. Pilings or columns shall be used to maintain the storage capacity of the floodplain. Concrete block support pilings shall be reinforced by placing reinforcing bars inside and extending them into the footing, filling the hollows with cement and using mortar to cement the blocks together. FEMA Publication 85, Manufactured Home Installation in Flood Hazard Areas, should be consulted for specific recommendations.
(3) 
Manufactured homes repaired or replaced due to substantial flooding or other causes shall be considered new structures and shall fully comply with § 182-9B of this chapter.
(4) 
Owners of manufactured home parks or subdivisions that are partially or fully within the floodplain shall file an evacuation plan with the Director of Emergency Management. New manufactured home parks shall provide an access road elevated to the flood protection elevation.
D. 
Anchoring. All structures shall be firmly anchored in accordance with acceptable engineering practices to prevent flotation, collapse and lateral movement during flooding. All air ducts, large pipes and storage tanks located below the flood protection elevation shall be firmly anchored to resist flotation.
E. 
Utilities.
(1) 
Electric. Distribution panel boxes shall be installed at least two (2) feet above the flood protection elevation. All outlets and electrical installations, such as heat pumps, air conditioners, water heaters, furnaces, generators and distribution systems shall be installed at or above the flood protection elevation.
(2) 
Plumbing. Toilets, sinks, showers, water heaters, pressure tanks, furnaces and other permanent plumbing installations shall be installed at or above the flood protection elevation.
(3) 
Gas. Gas meters and gas appliances shall be installed at or above the flood protection elevation.
(4) 
Water supply and sanitary facilities. Water supply distribution and sanitary disposal collection systems shall be designed to minimize or eliminate the infiltration of floodwaters into the systems or discharges from the systems into floodwaters and shall be located and constructed so as minimize or eliminate flood damage. On-site sewage disposal systems shall meet these same standards.
A. 
Where feasible, accessory structures and garages shall be located out of the floodplain or elevated to or above the flood protection elevation. When these measures are not feasible, the following shall apply:
(1) 
The floor of the structure shall be at or above grade.
(2) 
The structures shall be located, oriented and constructed so as to minimize flood damage.
(3) 
The structure shall be firmly anchored to prevent flotation.
B. 
Attached garage.
(1) 
Attached garages, used solely for parking of vehicles, storage or building access and no more than six hundred (600) square feet in size, are exempt from the elevation requirement but shall be elevated to the greatest extent possible. Attached garages shall meet the venting requirements found in § 182-12B of this chapter. All interior walls, ceilings and floors below the flood protection elevation shall be unfinished.
(2) 
No machinery, electrical devices or appliances shall be located below the flood protection elevation. A nonconversion agreement shall be signed by the property owner.
C. 
Detached garages and accessory structures.
(1) 
Accessory structures or detached garages, if less than three hundred (300) square feet in size and used solely for the parking of vehicles and limited storage, are exempt from the elevation requirements. No machinery, electric devices or appliances shall be located below the flood protection elevation. All interior walls, ceilings and floors located below the flood protection elevation shall remain unfinished. A nonconversion agreement shall be signed by the property owner.
(2) 
Accessory structures or detached garages between three hundred (300) square feet and six hundred (600) feet in size may be constructed below the flood protection elevation under the conditions of § 182-19 of this chapter.
(3) 
An accessory structure or garage larger than six hundred (600) square feet in size shall be elevated to the proper flood protection elevation.
D. 
Recreational vehicles.
(1) 
Recreational vehicles located within the floodplain may be exempt from the elevation and anchoring requirements, provided that they are:
(a) 
Located on the site less than one hundred eighty (180) consecutive days per year.
(b) 
Fully licensed and ready for highway use.
(c) 
Properly permitted.
(2) 
A recreational vehicle is ready for highway use if it is on its wheels and jacking system, is attached to the site only by quick-disconnect-type utilities and securing devices and has no permanently attached additions. If it cannot meet all of these criteria, the recreational vehicle shall be considered a manufactured home and is subject to the elevation and construction standards of this chapter.
E. 
Fill.
(1) 
Fill shall not be placed in the floodway. Fill shall not be used for structural support in the coastal high hazard area.
(2) 
Fill shall consist of soil and rock materials only. Dredge material shall be used as fill only upon certification of suitability by a registered professional geotechnical engineer. Landfill, rubble fills, dumps and sanitary fills shall not be permitted in the floodplain.
(3) 
Fill used to support structures shall be compacted to ninety-five percent (95%) of the maximum density obtainable by the Standard Proctor Test (ASTM Standard D-698) and its suitability to support structures certified by a registered professional engineer. Fill slopes shall be no greater than two horizontal to one vertical (2:1). Flatter slopes may be required where velocities may result in erosion.
(4) 
The use of fill shall not increase flooding onto or interfere with drainage from neighboring properties.