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How Deep is Charleston Harbor?

Ship crossing under the Ravenel Bridge, Charleston Harbor. Photo by Chris Huber.

Charleston Harbor plays a critical role in the South Carolina economy, serving as a major port for containerized cargo, cruise ships, and recreational boaters.

Recently, the Charleston Harbor Deepening Project was completed, which aimed to deepen the harbor to a depth of 52 feet, making it the deepest harbor on the East Coast of the United States.

How Deep is Charleston Harbor?

The entrance channel to the harbor — formerly lit by the Morris Island lighthouse — has been deepened to 54 feet, up from the previous depth of 47 feet, enabling larger vessels to call on the Port of Charleston any time, any tide.

The inner harbor has depths ranging from around 35 feet to 45 feet, with some areas deeper than 50 feet, which provide a deep-water port for military vessels.

Turning basins were also widened in front of both the Wando Welch Terminal and Leatherman Terminal, well past the Ravenel Bridge, enabling ships to more easily pass and turn around while navigating the port.

The depth in specific areas may be affected by sedimentation and dredging activities. Sedimentation occurs naturally as sediment and silt from nearby rivers and streams settle in the harbor, which can reduce the depth of the water in some areas. Dredges come in to combat this, in a never-ending battle with Mother Nature.

The Charleston Harbor Deepening Project

If you look closely, you can see a dolphin jumping at the bow of the ship.

The Charleston Harbor Deepening Project was crucial to maintaining South Carolina’s economic competitiveness as larger ships continue to flow through the Port of Charleston.

The project aimed to deepen the harbor to a depth of 52 feet and the entrance channel to 54 feet, enabling mega container ships to call on the port no matter the tidal conditions.

The project began in 2011 with a study by the U.S. Army Corps of Engineers, which determined the federal interest in the deepening of Charleston Harbor.

The project received Congressional authorization in December 2016 and was fully funded through state and federal dollars, with a total cost of $565 million. The deepening project progressed more quickly than any federal deepening project to date, and in December 2019, the project was fully funded to completion.

The Army Corps awarded five dredging contracts — three to Great Lakes Dredge and Dock Corp., one to Norfolk Dredging Co. and one to Marinex Construction Inc. — and the work was completed in four years.

Benefits of the Deepening Project

The deeper harbor provides a more competitive option for shipping companies, enabling larger vessels to dock at the port. This allows for more efficient cargo transport, increased port productivity, and lower shipping costs.

This is also crucial to South Carolina’s economic success, as it enables SC Ports to remain globally competitive in the face of record cargo volumes and bigger ships. Ultimately it will help to further connect South Carolina to global markets and promote economic success for the region.

Environmental Concerns

There were several environmental concerns associated with the Charleston Harbor Deepening Project, such as the potential impact on water quality, sedimentation, and marine life.

To mitigate these concerns, the project included several environmental monitoring and mitigation measures. For instance, before dredging work began, the project conducted extensive environmental surveys to identify and protect critical habitats and species.

During the project, the dredging work was conducted in phases to minimize the potential impact on marine life, and the dredging contractors used specialized equipment and techniques to reduce the amount of sediment released back into the water.

Additionally, the project included measures to minimize the impact of dredging on water quality, such as using silt curtains and monitoring water quality throughout the project.

Overall, the project aimed to balance the economic benefits of the deepened harbor with the need to protect and preserve the environment. While there were some concerns regarding the potential environmental impact of the project, the measures taken by the project helped to mitigate these concerns and ensure that the project was conducted in an environmentally responsible manner.


The completion of the Charleston Harbor Deepening Project has greatly increased the harbor’s capabilities, further connecting South Carolina to global markets, and promoting economic success for the region.

While it may not have been the ideal thing for the environment, it was conducted with professional standards to ensure that as minimal of an impact as possible was made.

As larger vessels continue to call on the Port of Charleston, the deeper harbor will provide a more competitive option for shipping companies and enable South Carolina to remain a key player in the global marketplace.

The additional revenue generated, at least in part, is likely to translate into upgrades for infrastructure that will benefit not only the shipping companies but also the people living in Charleston, making for a net positive overall.