City of Spokane

Spokane Municipal Code

Home
Title 17E
Chapter 17E.030
Section 17E.030.140
 

Title 17E Environmental Standards

Chapter 17E.030 Floodplain Management

Section 17E.030.140 Specific Standards

In all areas of special flood hazards where base flood elevation data has been provided as set forth in this chapter, the following provisions are required:

  1. Residential Construction.
    1. New construction and substantial improvement of any residential structure shall have the lowest floor, including basement, elevated two feet above the base flood elevation.
    1. Fully enclosed areas below the lowest floor that are subject to flooding are prohibited, or 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 shall meet or exceed the following minimum criteria:
      1. 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 must be provided.
      1. The bottom of all openings must be no higher that one foot above grade.
      1. Openings may be equipped with screens, louvers, or other coverings or devices provided that they permit the automatic entry and exit of floodwaters.
  1. Nonresidential Construction.

New construction and substantial improvement of any commercial, industrial or other nonresidential structure shall either have the lowest floor, including basement, elevated two feet above the base flood elevation; or, together with attendant utility and sanitary facilities, shall:

    1. be floodproofed so that below two feet or more above the base flood level the structure is watertight with walls substantially impermeable to the passage of water;
    1. have structural components capable of resisting hydrostatic and hydrodynamic loads and effects of buoyancy;
    1. 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 provisions of this subsection based on their development and/or review of the structural design, specifications and plans. Such certifications shall be provided to the local administrator as set forth in SMC 17E.030.080;
    1. nonresidential structures that are elevated, not floodproofed, must meet the same standards for space below the lowest floor as described in subsection (A) of this section;
    1. applicants who are floodproofing nonresidential buildings shall be notified that flood insurance premiums will be based on rates that are one foot below the floodproofed level (e.g., a building floodproofed to the base flood level is rated as one foot below).
  1. Manufactured Homes.
    1. All manufactured homes to be placed or substantially improved within zones A1-A30, AH , AO and AE on the City’s flood insurance rate map on sites:
      1. outside of a manufactured home park or subdivision;
      1. in a new manufactured home park or subdivision;
      1. in an expansion to an existing manufactured home park or subdivision, or
      1. in an existing manufactured home park or subdivision on which a manufactured home has incurred “substantial damage” as the result of a flood;

shall be elevated on a permanent foundation such that the lowest floor of the manufactured home is elevated two feet above the base flood elevation and be securely anchored to an adequately anchored foundation system to resist flotation, collapse and lateral movement.

    1. Manufactured homes to be placed or substantially improved on sites in an existing manufactured home park or subdivision within zones A1-30, AH, AO and AE on the City’s flood insurance rate map that are not subject to the above manufactured home provisions shall be elevated so that either:
      1. the lowest floor of the manufactured home is elevated two feet or more above the base flood elevation; or
      1. the manufactured home chassis is supported by reinforced piers or other foundation elements of at least equivalent strength that are no less that thirty-six inches in height above grade and is securely anchored to an adequately anchored foundation system to resist flotation, collapse, and lateral movement.
  1. Recreational Vehicles.

Recreational vehicles placed on sites within zones A1-30, AH, AO and AE on the City’s flood insurance rate map are required to either:

    1. be on the site for fewer that one hundred and eighty consecutive days;
    1. be fully licensed and ready for highway use, 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; or
    1. meet the requirements of subsection (C) of this section and the elevation and anchoring requirements for manufactured homes.

Date Passed: Monday, February 21, 2005

Effective Date: Wednesday, March 30, 2005

ORD C33583 Section 2