Florida Keys Study Ranks Roads in Need of Flood Mitigation

• Our team conducted a roadway vulnerability assessment for 311 miles of roadway in Monroe County.
• The study yielded an adaptation list of 83 potential project areas.
• We gave the roadways a ranking so county officials know which roads need to be addressed first and which can wait until 2040 and beyond.
• Using the results of our study, Monroe County has won several grants to help fund road improvement projects. 

Monroe County, home of the Florida Keys, is a limestone archipelago that extends 115 miles from a point south of Miami westward to Key West in the Gulf of Mexico. The county is among the most vulnerable communities in the nation to rising sea levels and ranks among the highest areas in the country for impacts from tidal flooding. 

Even on sunny days, the Keys have experienced record “king tides.” Ocean water flows into drainage systems and inundates streets and yards. Once flooded, those neighbourhoods may remain flooded for weeks to months, preventing people from accessing their neighbourhoods and cutting those areas off from services like waste collection and even emergency services. 

Hoping to make the county more resilient, Monroe County engaged our team to conduct a roadway vulnerability assessment for the 311 miles of county-maintained roadways. The long-term roads adaptation plan sought to mitigate the impacts of sea level rise, provide high level conceptual design and cost estimates.

In the scope of our study, we evaluated the 311 miles of roadway and approximately 1,200 locations. To identify the vulnerability of the roads, we gathered data on future sea level rise conditions (provided by our coastal hydrology team), king tide predictions, elevation, the location of environmentally sensitive areas, pavement conditions and modelled the impact of extreme events to see what the roadways would look like, giving us a full picture of the areas of concern. 

The study, which was completed in 2023, yielded an adaptation list which identified 83 potential project areas in the county that need to be addressed at varying levels of urgency — some within the next year and others delayed until 2040 and beyond. At public meetings, we got feedback from the community which validated the areas of concern we identified in the study as most urgent.

Next, we worked with Monroe County officials to look at the location of critical facilities, evacuation routes and the number of homes along roadways.

This two-step process allowed us to identify the vulnerability and criticality of each road and give the roads a score on a scale of one to five. With these scores, Monroe officials now have a list of which areas in the county will be impacted and when, allowing them to prioritize funding for road projects. The county officials have also been able to apply for and receive grants for the projects using our study results as supporting documentation. 

To further help Monroe County, we developed planning level cost estimates for the affected roadways and provided supporting technical information to facilitate the projects. We are now working on several of the identified projects and performing similar studies in other parts of the Florida Keys.