Wet Floodproofing: Flood Adaptation Measure


Wet-floodproofing scheme on pier shed. ©Port of San Francisco


PHYSICAL INFRASTRUCTURE
SHORELINE LOCATION:
Asset Specific




DESIGN LIFE
ADAPTABILITY
IMPACT ON THE WATERFRONT
CONSTRUCTION COST
N/A
N/A
Living with Water
TBD


COASTAL FLOOD HAZARDS MITIGATED:
Sea Level Rise
Storm Surge
Groundwater
Waves
Erosion


MEASURES COMPATABILITY
ECOSYSTEM SERVICES: Measure may affect these shoreline values
Flood
Seismic
All
All
Aquatic Habitat
Terrestrial Habitat
Water Quality
Carbon Storage


DESCRIPTION:
The space below the design flood elevation is constructed with flood-damage resistant materials in combination with flood vents to allow water to enter the structure and allow hydrostatic pressures to equalize. The enclosed space is built with flood damage resistant materials that do not need to be replaced if flooded, including pressure-treated plywood, concrete, and cement board. Flood vents are installed in the walls of the enclosure to let flood waters enter and leave by gravity, which allows forces on either side of the structure’s walls to equalize. This prevents the structure and foundation from collapsing in the event of a flood.


CONSIDERATIONS:
ADVANTAGES:
DISADVANTAGES:
  • NEED CONTENT
  • Wet floodproofing is generally less expensive than dry flood-proofing.
  • Wet floodproofing, unlike dry floodproofing, does not rely on advanced planning or preparation.
  • Allows internal and external hydrostatic pressures to equalize, lessening the loads on walls and floors.
  • Extensive cleanup may be necessary if the structure becomes wet inside and possibly contaminated by sewage, chemicals, and other materials borne by floodwaters.
  • Pumping floodwaters out too soon after a flood may lead to structural damage.
  • Periodic maintenance may be required.
  • Does not minimize the potential damage from high-velocity flood flow and wave action.


CONSTRUCTION IMPACTS TO THE PUBLIC:
SEA LEVEL RISE ADAPTATION OPPORTUNITIES:
CASE STUDIES:
  • NEED CONTENT
  • NEED CONTENT
  • NEED CONTENT


DESIGN OPPORTUNITIES:
Ecological Enhancements
Urban Design
Form
  • N/A
  • N/A
  • N/A


INSTALLATION AND CONSTRUCTABILITY CONSIDERATIONS:

  • If the duration of the flood is longer than 1 day, wet floodproofing is not a reasonable approach to protecting a structure.
  • Flood vents must be engineered to comply with energy code requirements for the building envelope.
  • If basement utilities cannot be relocated to a higher level, they can be protected by being placed in a watertight room or enclosure made of impermeable material such as concrete.

OPERATION AND MAINTENANCE CONSIDERATIONS:

  • Wet floodproofed spaces require extensive cleaning and/or replacement of finishes following flooding, and may present exposure to sewage, chemical, or other hazardous materials in floodwaters.
  • Annual maintenance of wet proofing equipment is required to ensure proper performance.


Download the Wet Floodproofing Factsheet.

Learn about other types of measures from our Measures Explorer page.


Wet-floodproofing scheme on pier shed. ©Port of San Francisco


PHYSICAL INFRASTRUCTURE
SHORELINE LOCATION:
Asset Specific




DESIGN LIFE
ADAPTABILITY
IMPACT ON THE WATERFRONT
CONSTRUCTION COST
N/A
N/A
Living with Water
TBD


COASTAL FLOOD HAZARDS MITIGATED:
Sea Level Rise
Storm Surge
Groundwater
Waves
Erosion


MEASURES COMPATABILITY
ECOSYSTEM SERVICES: Measure may affect these shoreline values
Flood
Seismic
All
All
Aquatic Habitat
Terrestrial Habitat
Water Quality
Carbon Storage


DESCRIPTION:
The space below the design flood elevation is constructed with flood-damage resistant materials in combination with flood vents to allow water to enter the structure and allow hydrostatic pressures to equalize. The enclosed space is built with flood damage resistant materials that do not need to be replaced if flooded, including pressure-treated plywood, concrete, and cement board. Flood vents are installed in the walls of the enclosure to let flood waters enter and leave by gravity, which allows forces on either side of the structure’s walls to equalize. This prevents the structure and foundation from collapsing in the event of a flood.


CONSIDERATIONS:
ADVANTAGES:
DISADVANTAGES:
  • NEED CONTENT
  • Wet floodproofing is generally less expensive than dry flood-proofing.
  • Wet floodproofing, unlike dry floodproofing, does not rely on advanced planning or preparation.
  • Allows internal and external hydrostatic pressures to equalize, lessening the loads on walls and floors.
  • Extensive cleanup may be necessary if the structure becomes wet inside and possibly contaminated by sewage, chemicals, and other materials borne by floodwaters.
  • Pumping floodwaters out too soon after a flood may lead to structural damage.
  • Periodic maintenance may be required.
  • Does not minimize the potential damage from high-velocity flood flow and wave action.


CONSTRUCTION IMPACTS TO THE PUBLIC:
SEA LEVEL RISE ADAPTATION OPPORTUNITIES:
CASE STUDIES:
  • NEED CONTENT
  • NEED CONTENT
  • NEED CONTENT


DESIGN OPPORTUNITIES:
Ecological Enhancements
Urban Design
Form
  • N/A
  • N/A
  • N/A


INSTALLATION AND CONSTRUCTABILITY CONSIDERATIONS:

  • If the duration of the flood is longer than 1 day, wet floodproofing is not a reasonable approach to protecting a structure.
  • Flood vents must be engineered to comply with energy code requirements for the building envelope.
  • If basement utilities cannot be relocated to a higher level, they can be protected by being placed in a watertight room or enclosure made of impermeable material such as concrete.

OPERATION AND MAINTENANCE CONSIDERATIONS:

  • Wet floodproofed spaces require extensive cleaning and/or replacement of finishes following flooding, and may present exposure to sewage, chemical, or other hazardous materials in floodwaters.
  • Annual maintenance of wet proofing equipment is required to ensure proper performance.


Download the Wet Floodproofing Factsheet.

Learn about other types of measures from our Measures Explorer page.