Sea Level Rise and Delaware’s Bridges

• Vivian Whoriskey, Environmental Engineering, Yale University

• Jennifer McConnell, Civil Engineering, University of Delaware

The purpose of this paper is to investigate how sea level rise (SLR) affects Delaware’s civil infrastructure, specifically, its bridges, and how that will impact the public. A State of Delaware report on SLR labeled their roads and bridges as a resource that is at “high risk” due to SLR. However, there has been no further effort to identify which bridges are most at risk. This paper takes a first step of identifying which bridges are at most risk, and the impact to the public on the closure of these bridges, to inform government officials and community members in preparing for SLR. This research used Python and ArcGIS to create a map of Delaware’s bridges overlaid with a SLR map to conduct a visual analysis of which bridges will be inundated at 1 and 3 feet of SLR. Additionally, this work collected and analyzed data from: (1) the CDC’s Social Vulnerability Index (SVI), which uses census data to rank the vulnerability of different census tracts and (2) traffic data from the National Bridge Inventory. This data was used to allow for a more informed decision to be made about at-risk bridges based on local community demographics and bridge usage. The results of this analysis found 30 bridges will be permanently inundated with 1 foot of SLR, affecting an average of 48,972 vehicles daily if preventative action is not taken now. The data collected in this paper can be used to help government officials make a decision about what approach is best for these bridges: managed retreat, or adaptation.