For many the idea of sea level rise and its associated impacts are thought of as future events. But, here in Charleston it’s already a part of life. Coastal flooding is a major issue that the city faces. All it takes is just the right tide, or even worse, an extreme high tide paired with a torrential downpour during rush hour, and Charleston’s streets become fingers of the Atlantic Ocean that no car can ford. It’s not hard to fathom that these flooded streets will one day become creeks and marshes. And in many cases that is what they once were.
As far back as the 18th century, Charlestonians have made a practice of expanding the city’s footprint by filling creeks and marshes. Alfred O. Halsey’s Historic Charleston on a Map provides an amazing illustration of the change to the peninsula’s landscape (Preservation Society of Charleston [PSOC]). The map shows that many areas that frequently flood are atop man made land.
The aptly named Water Street in the South of Broad neighborhood was originally Vanderhorst Creek, until it was filled in 1792. Many are familiar with the images of kayakers paddling through the City Market after wayward bands from Hurricane Isaac flooded the city. This could have been a common sight if what was once Governor’s Creek wasn’t filled in to create Market Street in first decade of the 19th century. Both the Charleston Village and Cannonborough neighborhoods were filled in during the mid 1800s and both are notorious for their flood problems. The city has continued to alter the coastline as late as the 1960s. During this time, Lockwood Boulevard was constructed which resulted in cutting off the Charleston Municipal Yacht Basin from the Ashley River and converted it into a placid pond (Thompson 2013).
With all this in mind, I became curious to see what the future may have in store for the Holy City. Using data from our Sea Level Rise and Coastal Flooding Impacts Viewer and a historic map of the Charleston Harbor from the NOAA Office of Coast Survey’s Historical Map and Chart Collection, I created a map that compares Charleston’s past shoreline to areas that could potentially become inundated if coastal waters rise three feet above mean higher high water. This was a fairly simple process that involved georeferencing the historic map and then overlaying a layer that depicts areas that are susceptible to inundation at three feet of sea level rise. As it turns out, the areas shown as water or marsh on the map match up rather well with the areas that are vulnerable to inundation at this scenario.
If you’d like to explore the map, please check out The History Behind Flooding in Charleston, South Carolina story map in the NOAA GeoPlatform Map Gallery. This interactive map allows you to use a ‘spyglass’ to explore the relationship between Charleston’s historic shorelines and areas of future flood vulnerability.
Preservation Society of Charleston. “Hasley Map”. Hasley Map Preservation Research Project. Preservation Society of Charleston, 2014. 2 May 2014.
Thompson, Evan R. “The Historical Reason why Charleston’s Streets Flood”. Charleston City Paper 21 August 2013. Web. 3 May 2014. <http://www.charlestoncitypaper.com/charleston/the-historical-reason-why-charlestons-streets-flood/Content?oid=4706751>