In October 2018, the Army Corps of Engineers initiated a three-year, $3 million feasibility study to investigate coastal storm risks on the Charleston peninsula and develop a feasible plan to mitigate these risks. The study concludes with a final report in 2021.
On April 20, the Corps released the Charleston Peninsula Coastal Flood Risk Management Study’s initial 18 months of analysis in a draft report. The report details the peninsula’s complex coastal storm risks and describes the outlines of a potential engineering solution. The Corps kicked off the study’s public comment period on April 20. The community is encouraged to provide initial feedback and ask questions through June 19.
Here are 5 things you should know about the study.
1. The Charleston peninsula is vulnerable to major coastal storms.
Resting on low-lying, often reclaimed land, the Charleston peninsula has seen an increase in higher tidal activity, more severe and precipitous storms and relative sea level rise. In the last few years, the peninsula has experienced the city’s highest-ever recorded tides. Sea level, which has risen more than a foot since the harbor gauge was installed 100 years ago, is projected to continue rising through the next century.
2. The medical district and historic areas are most at risk during coastal storm events.
The peninsula is home to some of state’s oldest historic structures and a comprehensive medical district. There are 12,095 structures on the peninsula with a structural value of $8.5 billion and a content value of $5.5 billion. During previous major coastal storm events, these areas saw some of the greatest surge inundations and subsequent damages. In some cases, hospitals were pushed to extreme measures, resorting to johnboats and tactical vehicles to transport critical patients, limiting facility access and reducing operating room capacity. Today, the only transplant center in South Carolina, a Level I trauma center and a regionally-servicing children’s hospital are built on these flood-prone areas.
3. The current storm surge wall alignment and elevation are conceptual.
As part of the feasibility review process, the Army Corps works with local stakeholders to develop and then narrow down several alternatives into a feasible, comprehensive solution. During the public comment period, the Corps encourages input on the selected alternative and uses feedback to inform the remaining study analysis. Currently, the selected plan includes three key features: a perimeter storm surge wall with 12-foot NAVD88 elevation, a breakwater structure in the harbor, and nonstructural measures. At this stage of the study, the storm surge wall’s exact alignment and elevation, as well as many other specifics, remain conceptual and require further review.
4. The plan will mitigate coastal storm risks for all low-income housing on the peninsula.
The study area spans approximately 8,000 square miles along the Charleston peninsula, stretching from the Battery to the city’s border with North Charleston. The plan takes all structures and resources in the area into account, including all low-income housing and ongoing and permitted development. The plan recommends various risk mitigation features based on an area’s topography and storm surge risk factors. Areas and structures outside the storm surge wall’s conceptual alignment generally rest on higher elevation or have more robust structural elevation features. For these areas, the plan recommends supportive measures that are more unique to each area’s needs, such as ring dikes, temporary barriers and home raising. Structures on the southern end of the peninsula rest on lower, reclaimed land and therefore are more susceptible to storm surges and require significant mitigation measures, such a storm surge wall. Regardless the strategy, the final plan would mitigate coastal storm risks for all communities across the entire study area.
5. The Corps encourages the public to provide initial feedback and questions through June 19.
Public input is critical to the study process. To encourage everyone to review the draft report, the Army Corps extended the public comment period from 30 to 60 days. All feedback is addressed in the final report. To provide feedback, complete the digital comment form or mail written comments to the Environmental & Planning Office at 69A Hagood Ave, Charleston, SC 29412. View the study’s interactive website here.