A new model developed by NCCOS-funded researchers shows that parts of Alabama’s coastal highways are likely to become damaged due to high groundwater levels. Decision-makers across coastal states can use the model’s framework, which incorporates localized rainfall and water level data, to guide and inform adaptive management of coastal roadways.
The combined effects of rising sea levels, extreme high tides, storm surges, and moderate to severe rainfall cause groundwater levels to rise, which could compromise road integrity. Over time, high groundwater levels create pressure on underlying roadbeds. Water infiltration into pavement layers can lead to cracks or potholes forming on road surfaces, creating hazards for drivers and resulting in costly road repairs.
Most damage risk models that predict road conditions focus primarily on extreme weather events and often overlook the long-term effects of elevated groundwater. The model in this study incorporated moderate rainfall conditions to better understand near-term saturation conditions that are likely to occur.
Model outputs showed that, under predicted sea level rise scenarios and frequent moderate rainfall, some sections of Alabama’s State Route AL-180 roadbed may remain saturated for extended periods. The areas most at risk for deterioration are those with low elevation, chronically high groundwater levels, and heavy vehicle use on wet pavement after rainfall events. AL-180 serves as the main connector from an outlying peninsula to the mainland and is a key hurricane evacuation route, so understanding and identifying potential vulnerabilities may help local transportation engineers minimize hazardous road conditions.
Additionally, accounting for groundwater saturation risk may inform and guide coastal roadway planning or infrastructure improvements for transportation stakeholders across the United States. By applying similar modeling methods to other locations, engineers can better predict vulnerabilities in coastal roads and highways. With this information, they can then take proactive steps to mitigate damage such as raising sections of road, upgrading roadway drainage systems, or proposing new roadway alignment.
This project is led by Auburn University in partnership with the Alabama Department of Transportation, along with a secondary project led by the University of New Hampshire. The full research teams are listed on the project pages. Both projects are funded through the NCCOS Effects of Sea Level Rise (ESLR) Program.
This work is authorized by the NOAA Authorization Act of 1992, Pub. L. 102-567 (Oct. 29, 1992); sec. 201(c), which authorizes appropriation for the NCCOS Competitive Research Program to augment and integrate existing programs of NOAA, and shall include efforts to improve predictions of coastal hazards to protect human life and personal property.
Citation: De Oliveira Sousa, B. J., Webb, B. M., Wright, D. B., Clement, T. P., & Vasconcelos, J. G. (2025). Conceptual data-driven approach for analyzing the vulnerability of coastal roadways to groundwater level changes. Journal of Environmental Management, 390, 126295. https://doi.org/10.1016/j.jenvman.2025.126295