Flood Zones Design Requirements in St. Tammany Parish

Flood Zones Design Requirements in St. Tammany Parish

Hierarchical interpretation of the codes:

• Louisiana Uniform Construction Code, with amendments through November 2015: http://lsuccc.dps.louisiana.gov/pdf/Title_17_UCC.pdf .
  • Building Code of St. Tammany (STP Government-specific code provisions amending the 2006 building codes, from http://www.stpgov.org/files/Development-%20Permits/Building_Code_Of_St__Tammany_(1).pdf , where and if not otherwise addressed in the LSUCC noted above.
  • IRC 2012 as adopted and amended above.

Summary by zone (based on IRC R322):

1. VE zones (Coastal high-hazard) per IRC 322.3
   1. Design open structure below the first floor (or blow-out walls).
   2. First floor needs to be above BFE to bottom of framing (or 1’ above BFE to bottom of framing where framing is perpendicular to the wave direction).
   3. Columns, piling, etc. to be designed to resist wave loading and scour (simultaneous with wind loading).
   4. All structural documents to be sealed by a PE.
2. Coastal AE zone (a portion of AE zone, adjacent to VE zone, in which potential exist for 1.5’ to 3’ waves as determined by stillwater depths of 2’ to 4’ and absence of obstructions to block waves) per IRC 322.2.
   1. Lowest floor must be above 1’ above BFE and be at least 12” above the street and curb high point.
   2. If enclosed below BFE, it must be for parking only and with minimum specified openings, use flood-resistant materials, and not use fill.
3. AE zones (inside the Special Flood Hazard Area with specific BFE defined).
   1. Lowest floor must be above BFE and be at least 12” above the street and curb high point.
   2. If enclosed below BFE, it must be for parking only and with minimum specified openings, use flood-resistant materials, and not use fill.
4. A zones (inside the SPHA but no specific BFE is defined; approximated).
   1. Lowest floor must be at least 12” above the street and curb.
   2. If enclosed below BFE, it must be for parking only and with minimum specified openings, use flood-resistant materials, and not use fill.
   3. [A0 zones should be at least 24” above surrounding grade.]
5. Shaded X zones (moderate flood hazard inside the 500-year flood area, in B zone in older FIRM maps).
   1. Lowest floor must be at least 12” above the street and curb[, and surrounding grade at least 12”.]
6. Unshaded X zones (minimal flood hazard, in C zone in older FIRM maps).
   1. Lowest floor must be at least 12” above the street and curb.

Other related provisions:

1. Lots less than 90’ wide can have no more than 24” fill unless in a subdivision with approved fill plans.
2. Fill placed in A zones must be mitigated.

A typical transect schematic found in many FEMA documents. From http://www.region2coastal.com/resources/coastal-mapping-basics/ .

Flood map for St. Tammany: http://maps.lsuagcenter.com/floodmaps/?FIPS=22103

St. Tammany unincorporated outside of Mandeville: effective data is 1980-1999 as shown.

Mandeville only: the effective data is the 2008 data shown in blue.

The “proposed” layer for information only, such as understanding what may be useful to considering in planning a new project, but not officially binding yet