Sea Level Rise Impacts Transportation Infrastructure
Expenditures of public funds for transportation infrastructure should consider the risk of local sea level rise.
Transportation infrastructure in U.S. coastal areas is increasingly vulnerable to local sea level rise. Given the high population density near the coasts, the potential exposure of transportation infrastructure to flooding is immense.
Northern Gulf of Mexico
Along the Northern Gulf Coast, an estimated 2,400 miles of major roadway and 246 miles of freight rail lines are at risk of permanent flooding within 50 to 100 years as relative sea level is expected to rise in the range of 4 feet (Figure 1). The Gulf Coast is particularly at risk to service disruptions due to a transportation network that is interdependent and relies on minor roads and other low-lying infrastructure. The Gulf Coast is home to seven of the ten largest commercial ports (by tons of traffic) in the country. The region also hosts a significant portion of the U.S. oil and gas industry, with its offshore drilling platforms, refineries, and pipelines. Roughly two-thirds of all U.S. oil imports pass through the Gulf. Sea level rise would potentially affect commercial transportation activity valued in the hundreds of billions of dollars annually through inundation of area roads, railroads, airports, seaports, and pipelines (U.S. Global Change Research Program, 2009). Figure 1 shows the Gulf Coast area roads at risk from sea-level rise.
Under current conditions, 1,900 miles of California's roadways are vulnerable to a 100-year flood event. This risk is projected to almost double to 3,500 miles if sea level rises 1.4 meters. Approximately one half of these roads are found in and around San Francisco Bay. (Pacific Institute, 2009). Figure 2 shows California roadways that are vulnerable to a 100-year coastal flood with 1.4 meter sea level rise.
Figure 1: View Larger Image Figure 2: View Larger Image
For further information:
U.S. Geological Survey National Assessment of Coastal Vulnerability to Sea Level Rise
NOAA Tides and Currents - Sea Level Online
NOAA Climate Services
U.S. Global Change Research Program