Why does it flood in Charleston?

Charleston City Market after a rainstorm
Charleston City Market after a rainstorm | Photo by Brian Kussard

Charleston’s Department of Stormwater Management created a report that details the complexity of local flooding with the purpose of educating the public about this persistent issue.

The Charleston area is low, flat, and next to the ocean, which has caused flooding issues for 300+ years and presented significant drainage challenges. It’s called the Lowcountry for a reason. 

However, the challenges the area faces are both natural and manmade. Natural factors include tides, duration of storms, and terrain. Manmade factors include inlets, system size, trash, and impervious surfaces. 

Follow a raindrop through Charleston. 💧 

What happens when it rains? 

  • Rain falls and runs off impervious surfaces
  • Stormwater runs into storm grates + collects in catch basins
  • Water flows from catch basins to stormwater pipes
  • Stormwater flows through pipes to the outfall into a body of water

Each step takes time. The system can slow down at any point when rain falls faster than the time each step takes. This causes standing water. Charleston’s drainage system can accommodate slow to moderate storms, but is overwhelmed by intense ones.

This issue persists partly because many of the pipes are too small to accommodate intense storms. Why doesn’t the city install larger pipes? The reasons are impracticality, limited space + extreme cost.

Charleston is currently working toward cost-effective solutions to flooding, including installing pump stations. According to the city, the issue is complex, so the solutions take time.

What can residents do to help?

  • Take an active role in keeping trash and debris off the streets and sidewalks
  • Take responsibility of drains in front of your home and business
  • Be on the lookout for anything that could clog a storm drain
  • Keep trash cans and dumpsters properly secured to prevent overturning
  • Try to remove the trash and debris from clogged drains once storms have passed
  • Call the Stormwater Department at 843-724-7367 to report clogged drains
  • Adopt a local storm drain

Dive into the full report.