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Congaree River Sediment Cleanup

The Congaree River begins in Columbia where the Saluda River and Broad River join together. It is bordered on the east by the City of Columbia and on the west by the Cities of Cayce and West Columbia. It flows for approximately 47 miles until it merges with the Wateree River. Congaree National Park is located about halfway down the river's course.

The Congaree River is a popular area for swimming, canoeing, fishing and other recreational activities. There are two official access points to the river near downtown Columbia. One is on the Cayce side of the river on Old State Road. The other is the Jordan Memorial Boat Ramp located at the west end of Rosewood Drive in Columbia.

The South Carolina Department of Health and Environmental Control (DHEC) has confirmed the presence of a tar-like material (TLM) in the sediments and soils of the Congaree River between the Gervais and Blossom Street bridges. DHEC has been overseeing the investigation and assessment of this site since June 2010.

Four cleanup alternatives have been evaluated by DHEC and a preferred cleanup alternative has been selected. Comments will be accepted on the cleanup alternatives through April 22, 2013. DHEC has determined that the water of the Congaree River is safe for recreational use. A potential human health risk only exists from direct skin contact with the TLM and affected sediments and soils. DHEC metal signs remain in place that warn against swimming or wading in the affected area to prevent any potential human exposure.

This DHEC webpage will serve as a central location to inform interested persons about environmental issues related to the Congaree River sediment cleanup. This webpage will be updated as new information becomes available.
Description: View of the Congaree River looking south from the Gervais Street Bridge
View of the Congaree River looking south from the Gervais Street Bridge

Site History

In June 2010, DHEC responded to a report of tar-like material (TLM) in the sediments of the Congaree River. The affected area begins directly south of the Gervais Street Bridge, extending approximately 200-300 feet into the river from the eastern shoreline, and approximately 2,000 feet south downriver towards the Blossom Street Bridge. At that time, DHEC began an investigation that included collecting surface water and sediment samples. DHEC also posted metal signs warning against swimming or wading in the area as a precautionary measure.

Preliminary sample results indicated that the TLM had similar chemical and physical characteristics as coal tar, a by-product of Manufactured Gas Operations which were common in cities from the late 1800s until the 1950s. Additional research found that the most likely source of the TLM was a former Manufactured Gas Plant (MGP) located northeast of the river at 1409 Huger Street that operated from about 1906 until the mid-1950s. Later this was the location of the city bus terminal until 2008.

MGPs produced a flammable gas from coal that was used for heating, cooking and lighting purposes prior to the construction of interstate natural gas pipelines. The coal tar material was a waste product from coal-gas production. Once the gas was produced, the coal tar by-product was discharged into a former stream which originated at what we know today as Finley Park, past the MGP site, and into the Congaree River just below the Gervais Street Bridge. The Huger Street MGP was operated by predecessor companies of South Carolina Electric & Gas (SCE&G) beginning in the early 1900s and ending in the 1950s, prior to the existence of environmental regulations and permitting.

SCE&G had previously entered into a Voluntary Cleanup Contract (VCC) with DHEC in August 2002 to conduct environmental assessment and cleanup activities at the former Huger Street MGP site. SCE&G has worked proactively and cooperatively with DHEC under its existing VCC to determine the extent of TLM in the Congaree River and to develop a plan for cleanup.