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WEB-BASED HANDBOOK (Legacy Edition). CLICK HERE to submit comments.
Because of staff changes and Randolph Langenbach's retirement from FEMA, these handbooks were never published on the FEMA website.  These are the only copies available.


Chapter 4:



Damage to buildings from flooding is caused by three factors: saturation, velocity, and hydrostatic forces. All retrofits of building structures must allow the accommodation of hydrostatic forces.

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Water saturation damage can include:

  • Inundation of buildings and their contents, or
  • Slope failures and instability.

Damage from high velocity flows might include:

  • Destruction of buildings and other structures;
  • Erosion/scouring of embankments, slopes, levees, and foundations; or
  • Drainage facility damage (i.e., dislodged or moved culverts).

Damage due to hydrostatic forces might include:

  • Destruction of buildings, foundations, and other structures, or
  • Soil erosion and/or subsoil movement.

In addition to direct damage, collateral damage might include:

  • Contamination of wells and other facilities inundated by sewage, hazardous materials, and other contaminants in the floodwater;
  • Debris from damaged homes, vegetation, orphaned drums, etc., causing debris dams or exacerbating velocity damage as projectiles impact structures; or
  • Siltation of ditches, roadways, drainage facilities, etc.

Actions taken during restoration can help buildings to resist flotation, collapse, and lateral movement during a flood event. The use of sealants to reduce seepage, installation of pumps and/or check valves to reduce interior water levels, and the elevation of building components can all protect buildings and their contents to varying degrees.


NOTE:  None of the mitigation measures in these Handbooks should be considered ‘pre-approved’ or otherwise automatically eligible for FEMA funding. Only FEMA staff can determine eligibility, once they have determined that an applicant is eligible and they have reviewed a project proposal.

FEMA HAZARD MITIGATION HANDBOOKS                                                                        Updated: June 13, 2002