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Sebago Maine Town Seal
This table is used for column layout.
 
Floodplain Management - Article VI
Development Standards
All developments in areas of special flood hazard shall meet the following applicable standards:

A.      New construction or substantial improvements of any structure shall:

1.      be designed or modified and adequately anchored to prevent flotation, collapse or lateral movement of structure resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy:
2.      use construction materials that are resistant to flood damage;
3.      use construction methods and practices that will minimize flood damage; and,
4.      use electrical, heating, ventilations, 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 flooding conditions.

B.      All new and replacement water supply systems shall be designed to minimize or eliminate infiltration of flood waters into the systems.

C.      All new and replacement sanitary sewage systems shall be designed and located to minimize or eliminate  infiltration of flood waters into the system and discharge from the system into flood waters.

D.      On-site waste disposal systems shall be located and constructed to avoid impairment to them or contamination from them during floods.

E.      All development shall be constructed and maintained in such a manner that no reduction occurs in the flood carrying capacity of any watercourse.

F.      New construction or substantial improvement of any residential structure located within:

1.      Zones A1-30, AE and AH shall have the lowest floor (including basement) elevated to at least one foot above the base flood elevation.
2.      Zones AO and AH shall have adequate drainage paths around structures on slopes, to guide floodwater away from the proposed structures.
3.      Zone AO shall have the lowest floor (including basement) elevated above the highest adjacent grade:

a.      at least one foot higher than the depth specified in feet on the community’s Flood Insurance Rate Map; or,
b.      at least three feet if no depth number is specified.
4.      Zone A shall have the lowest floor (including basement) elevated to at least one foot above the base flood elevation utilizing information obtained pursuant to Article III. G.1.b.; Article V.B; or Article VIII.D.

G.      New construction or substantial improvement of any non-residential structure located within;

1.      Zones A1-30, AE, and AH shall have the lowest floor (including basement)elevated to at least one foot above the base food elevation, or together with attendant utility and sanitary facilities shall:

a.      be floodproofed to at least one foot above the base flood level so that below that elevation the structure is watertight with walls substantially impermeable to passage of water;
b.      have structural components capable of resisting hydrostatic and hydrodynamic loads and the effects of buoyancy; and,
c.      be certified by a registered professional engineer or architect that the design and methods of construction are in accordance with accepted standards of practice for meeting the provisions of this section.  Such certification shall be provided with the application for a Flood Hazard Development Permit, as required by Article III.J and shall include a record of the elevation above mean sea level of the lowest floor including basement.

2.      Zones AO an AH hall have adequate drainage paths around structures on slopes, to guide floodwater away from them.

3.      Zone AO shall have the lowest floor (including basement) elevated above the highest adjacent grade:

a.      at least one foot higher than the depth specified in feet on the community’s Flood Insurance Rate Map; or,
b.      at least three feet if no depth number is specified; and,
c.      together with attendant utility and sanitary facilities be floodproofed to meet the elevations requirements of this section and floodproofing standards of Article VI, paragraph G.1.

4.      Zone A shall have the lowest floor (including basement) elevated to at least one foot above the base flood elevation utilizing information obtained pursuant to Article III.G.1.b; Article V.B; or Article VIII.D.

H.      New or substantially improved manufactured homes located within:

1.      Zones A1-30, AE, or AH shall:
a.      be elevated on a permanent foundation so that the lowest floor is at least one foot above the base flood elevation; and,
b.      be securely anchored to an adequately anchored foundation system to resist flotation, collapse, or lateral movement.  Methods of anchoring may include, but are not limited to:
(1)     over-the-top ties anchored to the ground at the four corners of the manufactured home, plus two additional ties per side at intermediate points (homes less than 40 feet long require one additional tie per side); or by,
(2)     frame ties at each corner of the home, plus five additional ties along each side at intermediate points (homes less than 50 feet long require four additional ties per side).
(3)     All components of the anchoring system described in Article VI.H.1 shall be capable of carrying a force of 4800 pounds.

2.      Zones AO and AH shall have adequate drainage paths around structures on slopes, to guide floodwater away from them.

3.      Zone AO shall have the lowest floor (including basement) elevated above the highest adjacent grade:
a.      at least one foot higher that the depth specified in feet on the community’s Flood Insurance Rate Map; or,
b.      at least three feet if no depth number is specified; and,
c.      meet the requirements of Article VI.H.1. (a) (b).

4.      Zone A shall have the lowest floor (including basement) elevated to at least one foot above the base flood elevation utilizing information obtained pursuant to Article III.G.1.b.; Article V.B; or Article VIII.D.

I.      Floodways

1.      In Zones A1-30 and AE encroachments, including fill, new construction, substantial improvement, and other development shall not be permitted in riverine areas, for which a regulatory floodway is designated on the community’s “Flood Boundary and Floodway Map,” unless a technical evaluation certified by a registered professional engineer is provided demonstrating that such encroachments will not result in any increase in flood levels within the community during the occurrence of the base flood discharge.

2.      In Zones A1-30 and AE riverine areas, for which no regulatory floodway is designated, encroachments, including fill, new construction, substantial improvement, and other development shall not be permitted unless a technical evaluation certified by a registered professional engineer is provided demonstrating that the cumulative effect of the proposed development, when combined with all other existing development and anticipated development will not increase the water surface elevation of the base flood more than one foot at any point within the community; and,


3.      In Zone A riverine areas, in which the regulatory floodway is determined to be the channel of the river or other water course and the adjacent land areas to a distance of one half the width of the floodplain as measured from the normal high water mark to the upland limit of the floodplain, encroachments, including fill, new construction, substantial improvement, and other development shall not be permitted unless a technical evaluation certified by a registered professional engineer is provided meeting the requirements of Article VI, paragraph I.2.

J.      New construction or substantial improvement of any structure in Zones A1-30, AE, AO, AH and A that meets the development standards of Article VI, including the elevation requirements of Article VI, paragraphs F,G, or H and is elevated on posts, columns, piers, piles, “stilts,” or crawlspaces less than three feet in height may be enclosed below the elevations requirements provided all the following criteria are net or exceeded:
                
1.      Walls, with the exception of crawlspaces less than three feet in height, shall not be part of the structural support of the building; and,
2.      Enclosed areas are not “basements” as defined in Article XIII; and,
3.      Enclosed areas shall be designed to automatically equalize hydrostatic flood forces on exterior walls by allowing for the entry and exit of floodwater.  Designs for meeting this requirement must either:      

a.      be certified by a registered professional engineer or architect; or,
b.      meet or exceed the following minimum criteria;
(1)     a minimum of two openings having a total net area or not less than one square inch for every square foot of the enclosed area;
(2)     the bottom of all openings shall be no higher that one foot above the lowest grade; and,
(3)     openings may be equipped with screens, louvers, valves, or other coverings or devices provided that they permit the entry and exit of flood waters automatically without any external influence or control such as human intervention, including the use of electrical and other non-automatic mechanical means; and,

4.      The enclosed area shall not be used for human habitation; and,

5.      The enclosed area may be used for building maintenance, access, parking vehicles, or storing of articles and equipment used for maintenance of the building.