Sec. 27-248.  Floodway fringe overlay district.

 

(a)  Permitted uses.  Any use permitted in Sec. 27-249 shall be permitted in the Floodway Fringe Overlay District.  No use shall be permitted in the district unless the standards of Sec. 27-247 are met.

 

(b)  Standards for the floodway fringe overlay district.

 

(1)       Require new construction or substantial improvements of residential structures to have the lowest floor, including basement elevated one foot above the base flood elevation.

 

(2)       Require new construction or substantial improvements of nonresidential structures to have the lowest floor, including basement, elevated one foot above the base flood elevation or, together with attendant utility and sanitary facilities be floodproofed so that below such a level the structure is water tight with walls substantially impermeable to the passage of water and with structural components having the capability of resisting hydrostatic and hydrodynamic loads and effects of buoyancy.  A registered professional engineer or architect shall certify that the standards of this subsection are satisfied. 

 

(3)       Require for all new construction and substantial improvements that fully enclosed areas below the lowest floor that are subject to flooding shall be designed to automatically equalize hydrostatic flood forces on exterior walls by allowing for the entry and exit of floodwaters.  Designs for meeting this requirement must either be certified by a registered professional engineer or architect or meet or exceed the following minimum criteria:

 

a.         A minimum of two openings having a total net area of not less than one square inch for every square foot of enclosed area subject to flooding shall be provided. 

 

b.         The bottom of all openings shall be no higher than one foot above grade. 

 

c.         Openings may be equipped with screens, louvers, valves, or other coverings or devices provided that they permit the automatic entry and exit of floodwaters.

 

(4)       Within AH zones, adequate drainage paths around structures on slopes shall be required in order to guide floodwaters around and away from proposed structures.

 

(5)        Appurtenant structures used exclusively for storage of vehicles and storage of other items readily removable in the event of a flood warning may have their lowest floor below one foot above the base flood elevation provided the structure is capable of withstanding hydrostatic and hydrodynamic forces caused by the base flood, or the structure is designed to automatically equalize hydrostatic flood forces on exterior walls by allowing for the entry and exit of floodwaters and provided that no utilities are installed in the structure except elevated or floodproofed electrical fixtures.  The designs for meeting the equalization of hydrostatic flood forces must either be certified by a registered professional engineer or architect or meet or exceed the following minimum criteria:

 

a.         A minimum of two openings having a total net area of not less than one square inch for every square foot of enclosed area subject to flooding shall be provided. 

 

b.         The bottom of all openings shall be no higher than one foot above grade; and 

 

c.         Openings may be equipped with screens, louvers, valves, or other coverings or devices provided that they permit the automatic entry and exit of floodwaters.

 

            If the structure is converted to another use, it must be brought into full compliance with the minimum standards governing such use. 

 

(c)  Mobile homes.

 

(1)       All mobile homes shall be anchored to resist flotation, collapse, or lateral movement.  Mobile homes must be anchored in accordance with local building codes or FEMA guidelines.  In the event that over-the-top frame ties to ground anchors are used, the following specific requirements (or their equivalent) shall be met:

 

a.         Over-the-top ties be provided at each of the four corners of the mobile home, with two additional ties per side at intermediate locations and mobile homes less than 50 feet long requiring one additional tie per side;

 

b.         Frame ties be provided at each corner of the home with five additional ties per side at intermediate points and mobile homes less than 50 feet long requiring four additional ties per side;

 

c.         All components of the anchoring system be capable of carrying a force of 4,800 pounds; and

 

d.         Any additions to the mobile home be similarly anchored.

 

(2)       Require that all mobile homes placed within Zones A1-30, AH and AE on the community's FIRM, be elevated on a permanent foundation such that the lowest floor of the mobile home is at or above the base flood elevation; and be securely anchored to an adequately anchored foundation system in accordance with the provisions of this section.

 

(d)  Located within the areas of special flood hazard established in Sec. 27-244 are areas designated as AO Zones.  These areas have special flood hazards associated with base flood depths of 1 to 3 feet where a clearly defined channel does not exist and where the path of flooding is unpredictable and indeterminate; therefore, the following provisions apply within AO Zones:

 

(1)       All new construction and substantial improvements of residential structures shall have the lowest floor (including basement) elevated above the highest adjacent grade at least as high as one foot above the depth number specified in feet on the community's FIRM or if no depth number is specified, at least two feet above the highest adjacent grade.

 

(2)       All new construction and substantial improvements of nonresidential structures shall:

 

a.         Have the lowest floor (including basement) elevated above the highest adjacent grade at least as high as one foot above the depth number specified in feet on the community's FIRM or if no depth number is specified, at least two feet above the highest adjacent grade; or

 

b.         Together with attendant utility and sanitary facilities be completely floodproofed to or above that level so that any space below that level is watertight with walls substantially impermeable to the passage of water and with structural components having the capability of resisting hydrostatic and hydrodynamic loads and effects of buoyancy.  Such certification shall be provided to the enforcement officer as set forth in Sec. 27-245.

 

(3)        Adequate drainage paths around structures on slopes shall be required in order to guide floodwaters around and away from structures. 

 

Source:  Ord. No. 4603, 1, 9-16-02; Ord. No. 5434, 3, 10-3-16