(b) Standards.
(1) New construction or substantial improvements of residential structures shall have the lowest floor, including the basement, elevated one foot above the base flood elevation.
(2) All new construction and substantial improvements of residential structures with basements within Zones A5 and A6 on the City's Federal Insurance Rate Map may be designed so that any basement area, together with attendant utilities and sanitary facilities below the regulatory flood elevation, is watertight with walls that are impermeable to the passage of water without human intervention. Basement walls shall be built with the capability to resist hydrostatic and hydrodynamic loads and the effects of buoyancy resulting from flooding which is one foot above the 100-year frequency flood and shall be designed so that minimal structural damage will occur if this design is exceeded. In addition, it is required that:
A. The bottom of the lowest basement openings, such as doors and windows, shall be placed at least one foot above the regulatory flood elevation.
B. All floodproofed residential basements shall be designed using the undrained or barge system.
C. The land around the entire foundation shall be filled at least to the regulatory flood elevation.
D. A floodproofed basement shall not be constructed within the floodway. E. Basements constructed in accordance with this paragraph shall not be used for sleeping purposes.
F. A registered professional engineer or architect shall certify that the standards of this paragraph are incorporated in the building plans and specifications. This certification shall include the specific elevation, in relation to mean sea level, to which the structure is floodproofed.
G. The City Inspector, or his or her authorized representative, shall make or require inspections of the basement construction work to ascertain compliance with this paragraph.
(3) A garage or storage building used exclusively for the storage of motor vehicles or of other items readily removable in the event of a flood warning may have the lowest floor below flood elevation, provided that the building structure is capable of withstanding hydrostatic and hydrodynamic forces caused by the 100-year flood, and provided, further, that no utilities are installed in the building, except elevated or floodproofed electrical fixtures. If the building is converted to another use, it must be brought into full compliance with the requirements of this chapter governing such use.
(4) New construction or substantial improvements of nonresidential structures shall have the lowest floor, including the basement, elevated one foot above the base flood elevation or, together with attendant utility and sanitary facilities, shall be floodproofed so that below such level the structure 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 the effects of buoyancy. A registered professional engineer or architect shall certify that the standards of this subsection are satisfied. Such certification shall be provided to the enforcement official as set forth in Section 1430.04(g).
(5) For all new construction and substantial improvements, 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 shall 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 not 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.
(6) Within AH Zones, adequate drainage paths around structures on slopes shall be required in order to guide floodwaters around and away from proposed structures.
(7) A. All manufactured homes shall be anchored to resist flotation, collapse or lateral movement. Manufactured homes shall be anchored in accordance with local building codes or FEMA guidelines. If over-the-top frame ties to ground anchors are used, the following specific requirements (or, their equivalent) shall be met:
1. Over-the-top ties shall be provided at each of the four corners of the manufactured home and two additional ties shall be provided per side at intermediate locations. Manufactured homes less than fifty feet long require one additional tie per side.
2. Frame ties shall be provided at each corner of the home and five additional ties shall be provided per side at intermediate points. Manufactured homes less than fifty feet long require four additional ties per side.
3. All components of the anchoring system shall be capable of carrying a force of 4,800 pounds.
B. All manufactured homes shall be placed within Zones A1-30 , AH and AE on the City's Flood Insurance Rate Map (FIRM), shall be elevated on a permanent foundation such that the lowest floor of the manufactured home is one foot above the base flood elevation, and shall be securely anchored to an adequately anchored foundation system in accordance with paragraph (b)(7)A. hereof.
(8) Located within the areas of special flood hazard established in Section 1430.03 are areas designed as AO Zones. Such areas have special flood hazards associated with base flood depths of one to three feet where a clearly defined channel does not exist and the path of flooding is unpredictable and indeterminate. The following provisions apply within AO Zones:
A. All new construction and substantial improvements of residential structures shall have the lowest floor (including the basement) elevated above the highest adjacent grade at least as high as the depth number specified in feet on the City's Flood Insurance Rate Map (at least two feet if no depth number is specified).
B. All new construction and substantial improvements of nonresidential structures shall:
1. Have the lowest floor (including the basement) elevated above the highest adjacent grade at least as high as the depth number specified in feet on the City's Flood Insurance Rate Map (at least two feet if no depth number is specified); or
2. Together with attendant utility and sanitary facilities, be completely floodproofed to or above the level provided for in paragraph (b)(8)B .1 hereof, so that any space below such 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 official as set forth in Section 1430.04(g).
C. Adequate drainage paths around structures on slopes shall be required in order to guide flood waters around and away from proposed structures.
(Ord. 1114. Passed 2-23-88.)