Raised Roadway: Flood Adaptation Measure - TYPE TEMPLATE




Example of raised roadway in Miami ©image credit


PHYSICAL INFRASTRUCTURE
SHORELINE LOCATION: Upland




DESIGN LIFE
ADAPTABILITY
IMPACT ON THE WATERFRONT
CONSTRUCTION COST
75+ Years
Low
Major Intervention
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
Structure Elevation
Floodproofing
Raised Structures
Soil Buttress
Liquefaction
Mitigation
Aquatic Habitat
Terrestrial Habitat
Water Quality
Carbon Storage


DESCRIPTION:
Elevated roadways will raise the street above an expected flood elevation. This requires the raising sections of the streets with additional material. The higher elevation of the street can also provide flood protection for assets and infrastructure on the landside of the street.


CONSIDERATIONS:
ADVANTAGES:
DISADVANTAGES:
  • Significant design and engineering required to elevate sections of roadways
  • Not suitable to low-lying areas
  • Provides physical protection from flooding for transportation assets on roadway
  • Protect inland areas from coastal flooding
  • Opportunity for improvement of utilities and infrastructure as part of project
  • High capital investment cost
  • Significant construction impacts
  • Existing utilities and transit will be disrupted or reconfigured


CONSTRUCTION IMPACTS TO THE PUBLIC:
SEA LEVEL RISE ADAPTATION OPPORTUNITIES:
CASE STUDIES:
  • Installation would be a significant construction project with considerable impacts
  • Construction will require rerouting and detours of traffic and pedestrian routes
  • Once installed, this measure would not be adaptable to various levels without retrofitting or coordination with other measures, such as raised barriers and raised features.
  • Purdy Street, Miami, Florida


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


DESIGN CONSIDERATIONS:

  • Significant design and engineering considerations would be required to elevate sections of the Southern Waterfront, though areas that are less developed would be more desirable.
  • Elevated sites will need to be engineered to resolve drainage issues or negative impacts to adjacent lower elevation areas.

SITE-SPECIFIC CONSIDERATIONS:

  • Not suitable for low-lying areas that are vulnerable to surge.

URBAN DESIGN CONSIDERATIONS:

  • Raised roadways would be a major re-design of public rights-of-way that will impact the relationship between streets and the surrounding properties and require significant urban design features.

INSTALLATION AND CONSTRUCTABILITY CONSIDERATIONS:

  • Elevated sites would need to be engineered to resolve any potential drainage issues or negative impacts to adjacent, lower elevation areas.
  • Constructability would also be complex depending on the limits of the recommended project.


Download the Raised Roadway Factsheet.

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




Example of raised roadway in Miami ©image credit


PHYSICAL INFRASTRUCTURE
SHORELINE LOCATION: Upland




DESIGN LIFE
ADAPTABILITY
IMPACT ON THE WATERFRONT
CONSTRUCTION COST
75+ Years
Low
Major Intervention
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
Structure Elevation
Floodproofing
Raised Structures
Soil Buttress
Liquefaction
Mitigation
Aquatic Habitat
Terrestrial Habitat
Water Quality
Carbon Storage


DESCRIPTION:
Elevated roadways will raise the street above an expected flood elevation. This requires the raising sections of the streets with additional material. The higher elevation of the street can also provide flood protection for assets and infrastructure on the landside of the street.


CONSIDERATIONS:
ADVANTAGES:
DISADVANTAGES:
  • Significant design and engineering required to elevate sections of roadways
  • Not suitable to low-lying areas
  • Provides physical protection from flooding for transportation assets on roadway
  • Protect inland areas from coastal flooding
  • Opportunity for improvement of utilities and infrastructure as part of project
  • High capital investment cost
  • Significant construction impacts
  • Existing utilities and transit will be disrupted or reconfigured


CONSTRUCTION IMPACTS TO THE PUBLIC:
SEA LEVEL RISE ADAPTATION OPPORTUNITIES:
CASE STUDIES:
  • Installation would be a significant construction project with considerable impacts
  • Construction will require rerouting and detours of traffic and pedestrian routes
  • Once installed, this measure would not be adaptable to various levels without retrofitting or coordination with other measures, such as raised barriers and raised features.
  • Purdy Street, Miami, Florida


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


DESIGN CONSIDERATIONS:

  • Significant design and engineering considerations would be required to elevate sections of the Southern Waterfront, though areas that are less developed would be more desirable.
  • Elevated sites will need to be engineered to resolve drainage issues or negative impacts to adjacent lower elevation areas.

SITE-SPECIFIC CONSIDERATIONS:

  • Not suitable for low-lying areas that are vulnerable to surge.

URBAN DESIGN CONSIDERATIONS:

  • Raised roadways would be a major re-design of public rights-of-way that will impact the relationship between streets and the surrounding properties and require significant urban design features.

INSTALLATION AND CONSTRUCTABILITY CONSIDERATIONS:

  • Elevated sites would need to be engineered to resolve any potential drainage issues or negative impacts to adjacent, lower elevation areas.
  • Constructability would also be complex depending on the limits of the recommended project.


Download the Raised Roadway Factsheet.

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