Building transportation resiliency

Storm Surge flood zoneTampa Bay has always been vulnerable to tropical storms and hurricanes. A Category 3 storm with winds of 111 to 129 mph could send water up to 21 feet deep surging inland. Even our monsoon-like summer rainstorms regularly floods low-lying roads. Adding to these hazards in the coming decades is sea level rise, which could increase Tampa Bay’s tides by 14 inches by 2040.

To deal with these risks, the MPO has been looking at ways to make our transportation system more resilient. Aided by a federal grant, and with the help of Hillsborough County’s Hazard Mitigation Section, FDOT, the University of Florida’s GeoPlan Center, the University of South Florida, and the Tampa Bay Regional Planning Council, the MPO has identified transportation links that are subject to inundation in the Vulnerability Assessment and Adaption Study. Hillsborough County’s Local Mitigation Strategy Working Group served as a sounding board for the study.

Some of the most critical and vulnerable segments identified in the study include:

 

  • Increasing the capacity of storm water systems to drain away water more quickly
  • Raising the profile of low-lying road segments to decrease exposure to flooding
  • Strengthening roadway bases or install wave attenuating devices to protect against erosion
  • Ensuring that parallel or secondary roads provide redundant access and capacity

No one can predict when it might occur, but what would happen if a Category 3 storm took the same path as our last direct hit by a hurricane (1921) on top of the expected sea level rise by 2040? We could experience gaps in road and rail networks due to portions being underwater, along with erosion, washouts, and other damage to road bases. Recovery of the transportation network could to take up to two months. Significant disruption to the transportation system could force drivers to travel longer distances, experience delays, or simply not be able to make their normal daily trips. In fact, TBRPC’s modeling estimates that each week of such disruption to the transportation system alone potentially causes economic losses of over $200 million in Hillsborough County.

So, what can be done to guard against such risks? Over time and ideally in the course of normal maintenance and rehabilitation, strategies include:

  • Increasing the capacity of storm water systems to drain away water more quickly
  • Raising the profile of low-lying road segments to decrease exposure to flooding
  • Strengthening roadway bases or install wave attenuating devices to protect against erosion
  • Ensuring that parallel or secondary roads provide redundant access and capacity

Investing in a more resilient transportation system is a choice the public will be asked to make in the 2040 Plan. The vulnerability study found that an investment of $37 million in larger drainage capacity, shoreline armoring and wave attenuation could cut Hillsborough County’s economic loss by 46 percent and shave two weeks off the transportation system’s recovery time.

The results of this pilot project will be shared as a national case study for of FHWA Climate Change Vulnerabilities Assessment Pilot program. For more information view the MPO’s project website or contact Allison Yeh at yeha@plancom.org or 813/273-3774 x351.

Top