Vegetated Crib Walls: Flood Adaptation Measure


©Prof. Victor Yepes Piqueras, Universitat Politecnica de Valencia



ECOLOGICAL INFRASTRUCTURE
WATER LEVEL RANGE: Intertidal to supratidal

SHORELINE LOCATION: Shoreline



DESIGN LIFE
ADAPTABILITY
IMPACT ON THE WATERFRONT
CONSTRUCTION COST
Decades
Medium
Minor Intervention
TBD


COASTAL FLOOD HAZARDS MITIGATED:
Enhancements can provide flood protection when combined with other physical infrastructure
Sea Level Rise
Storm Surge
Groundwater
Waves
Erosion


MEASURES COMPATIBILITY
ECOSYSTEM SERVICES: Measure may affect these shoreline values
Flood
Seismic
/
/
Seawalls, Levees
N/A
Aquatic Habitat
Terrestrial Habitat
Water Quality
Carbon Storage


DESCRIPTION:
Concrete crib walls are made of a concrete retaining wall framework filled with compacted backfill, which allows for vegetation to grow in crib wall openings. The vegetation prevents erosion and the crib wall openings can increase the effective roughness of the wall and, therefore, can reduce wave runup.


CONSIDERATIONS:
ADVANTAGES:
DISADVANTAGES:
  • Should be designed to account for future anticipated sea level rise.
  • Most suitable in low wave energy environments with a high tidal range.
  • Enhances aesthetics
  • Can improve riparian and fish habitats
  • Mostly successful only for bank protection in fluvial environments, limiting use in coastal applications.
  • Potential need to remove invasive species and debris, and trim vegetation.


CONSTRUCTION IMPACTS TO THE PUBLIC:
SEA LEVEL RISE ADAPTATION OPPORTUNITIES:
CASE STUDIES:
  • Landside access necessary. Access to the shoreline will be constricted due to construction, and may impact parts of the Promenade.
  • Plantings should be compatible with design high water levels and tide range.
  • Future sea level rise will submerge intertidal vegetation requiring re-planting or migration of the plants up the wall.
  • None cited


DESIGN OPPORTUNITIES:
Ecological Enhancements
Urban Design
Form
  • Native/local plant species should be installed to maximize habitat.
  • Vegetation improves aesthetics of seawalls and levees. Measures should be taken to prevent climbing over the wall.
  • Form accommodates flood requirements and spatial constrictions.


DESIGN CONSIDERATIONS:

  • Works best in areas with low wave and weak current conditions. Allows for high vegetation diversity in areas with a large tidal range.

SITE-SPECIFIC CONSIDERATIONS:

  • Water levels, waves, currents conditions and soil characteristics should be well defined.
  • Mostly used in terrestrial, rivers and bays with low wave and weak current conditions.

URBAN DESIGN CONSIDERATIONS:

  • Measures should be employed to discourage people from climbing the wall.

INSTALLATION AND CONSTRUCTABILITY CONSIDERATIONS:

  • Management of stormwater infiltration required.
  • Planting in an existing wall would be more difficult than in a new one because of existing vegetation may need to be removed.
  • Planting difficulty would be a function of wall height.

OPERATIONS AND MAINTENANCE CONSIDERATIONS:

  • Watering may be necessary initially for vegetation planted above high water and subsequently if the site experiences dry conditions.
  • Less maintenance is required over time once the vegetation becomes established (after up to 3 years).
  • Maintenance may be required to re-plant after storm damage, remove invasive species, trim the vegetation if it grows too much, or collects floating debris.


Download the Vegetated Crib Walls Factsheet.

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



©Prof. Victor Yepes Piqueras, Universitat Politecnica de Valencia



ECOLOGICAL INFRASTRUCTURE
WATER LEVEL RANGE: Intertidal to supratidal

SHORELINE LOCATION: Shoreline



DESIGN LIFE
ADAPTABILITY
IMPACT ON THE WATERFRONT
CONSTRUCTION COST
Decades
Medium
Minor Intervention
TBD


COASTAL FLOOD HAZARDS MITIGATED:
Enhancements can provide flood protection when combined with other physical infrastructure
Sea Level Rise
Storm Surge
Groundwater
Waves
Erosion


MEASURES COMPATIBILITY
ECOSYSTEM SERVICES: Measure may affect these shoreline values
Flood
Seismic
/
/
Seawalls, Levees
N/A
Aquatic Habitat
Terrestrial Habitat
Water Quality
Carbon Storage


DESCRIPTION:
Concrete crib walls are made of a concrete retaining wall framework filled with compacted backfill, which allows for vegetation to grow in crib wall openings. The vegetation prevents erosion and the crib wall openings can increase the effective roughness of the wall and, therefore, can reduce wave runup.


CONSIDERATIONS:
ADVANTAGES:
DISADVANTAGES:
  • Should be designed to account for future anticipated sea level rise.
  • Most suitable in low wave energy environments with a high tidal range.
  • Enhances aesthetics
  • Can improve riparian and fish habitats
  • Mostly successful only for bank protection in fluvial environments, limiting use in coastal applications.
  • Potential need to remove invasive species and debris, and trim vegetation.


CONSTRUCTION IMPACTS TO THE PUBLIC:
SEA LEVEL RISE ADAPTATION OPPORTUNITIES:
CASE STUDIES:
  • Landside access necessary. Access to the shoreline will be constricted due to construction, and may impact parts of the Promenade.
  • Plantings should be compatible with design high water levels and tide range.
  • Future sea level rise will submerge intertidal vegetation requiring re-planting or migration of the plants up the wall.
  • None cited


DESIGN OPPORTUNITIES:
Ecological Enhancements
Urban Design
Form
  • Native/local plant species should be installed to maximize habitat.
  • Vegetation improves aesthetics of seawalls and levees. Measures should be taken to prevent climbing over the wall.
  • Form accommodates flood requirements and spatial constrictions.


DESIGN CONSIDERATIONS:

  • Works best in areas with low wave and weak current conditions. Allows for high vegetation diversity in areas with a large tidal range.

SITE-SPECIFIC CONSIDERATIONS:

  • Water levels, waves, currents conditions and soil characteristics should be well defined.
  • Mostly used in terrestrial, rivers and bays with low wave and weak current conditions.

URBAN DESIGN CONSIDERATIONS:

  • Measures should be employed to discourage people from climbing the wall.

INSTALLATION AND CONSTRUCTABILITY CONSIDERATIONS:

  • Management of stormwater infiltration required.
  • Planting in an existing wall would be more difficult than in a new one because of existing vegetation may need to be removed.
  • Planting difficulty would be a function of wall height.

OPERATIONS AND MAINTENANCE CONSIDERATIONS:

  • Watering may be necessary initially for vegetation planted above high water and subsequently if the site experiences dry conditions.
  • Less maintenance is required over time once the vegetation becomes established (after up to 3 years).
  • Maintenance may be required to re-plant after storm damage, remove invasive species, trim the vegetation if it grows too much, or collects floating debris.


Download the Vegetated Crib Walls Factsheet.

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