About the research
This pilot project is one among many efforts by the Iowa Department of Transportation (DOT) and the Iowa Highway Research Board (IHRB) to develop and enhance a risk-based transportation asset management plan (TAMP). This project specifically focused on flooding and developed a suite of methodologies and proxy indicators to assess the risk of transportation assets to this hazard.
Multiple flood events were simulated on a segment of the transportation network to predict bridge closures based on overtopping in order to determine areas that may be especially vulnerable and the effects of this vulnerability on the transportation network.
Bridge sensitivity to flooding was analyzed using easily accessible data on bridge parameters and condition ratings to determine the structural condition of Iowa’s bridges, the geomorphic sensitivity of the channels, and the importance of each bridge for the transportation network. Data were reviewed from historical flood events that have resulted in damage to bridges, and a statistical analysis was performed of the potential correlations between flood damage and bridge features.
An analysis of road sensitivity was conducted using different road segments with different elevations and pavement types. The potential for closures was determined for different flooding scenarios based on the likelihood of overtopping, and the potential for damage to different pavement types was analyzed based on historical data.
Lastly, a segment of the transportation network was overlaid with different flooding scenarios to show subnetwork vulnerabilities.
In addition to moving towards a risk-based TAMP, it is expected that these methodologies and the resulting vulnerability indices and proxy indicators will feed into other parallel efforts to assess and enhance the resiliency of Iowa’s transportation infrastructure.