Markets / Flood Resiliency

Spring/Fishburne US 17 Drainage Improvements

South Carolina

US 17 in Downtown Charleston, known as the Crosstown, is a major artery for the City and has been plagued with flooding for many years. It is critical that this route remain an efficient lifeline for emergency response vehicles, commuters, and those evacuating in times of imminent hurricanes.

This drainage project will offer a solution to alleviate frequent flooding that causes property damage and heavy traffic along this critical corridor.  It will improve drainage in an area that covers approximately 20% of the City of Charleston.

In previous phases of the project, new stormwater pipe was installed and new tunnels were installed beneath the US 17 / Crosstown corridor.

Conti is working on Phase 4 of this project, which consists of the construction of a pump station / wet well structure and a cast-in-place triple box culvert outfall structure into the Ashley River.

Once all phases are complete, the new pump station between the Ashley River Bridges will be equipped with three pumps each capable of pumping 120,000 gallons per minute, three 850 horsepower diesel engines to power the pumps (thereby eliminating the need for electricity to run the pumps), and one back-up diesel generator to run the electrical and control systems in the event of a power failure.

Once the project is complete and the pump station is online, the Crosstown and surrounding areas should remain passable in all but the very worst storm events.


City of Charleston

Scope of Work:
  • Installation of 530’ x 40’ trestle in marsh and river
  • Installation and excavation of 530’ x 40’ x 15’ cofferdam for outfall construction and 150’ x 60’ x 40’ cofferdam for pump station installation
  • Driving of seventy-seven 42-inch dia. steel pipe piles
  • Driving of nine hundred 16” steel H-piles
  • Driving of seventy-four 12” and 14” prestressed concrete piles
  • Construction of 530’ long cast-in-place concrete outfall structure consisting of 3 parallel 8’ x 10’ box culvert sections below grade
  • Construction of 3-story 135’ x 55’ pump station 40 feet below grade, consisting of cast-in-place concrete and structural steel framing, to house three 66-inch diesel pumps
  • Placement of 8,000 cubic yards of concrete
  • Installation of dewatering pumps, tunnel drain pumps, silt pumps, sump agitation pumps, mechanical bar screens, conveyors, and flap gates
  • Installation of 4” to 36” ductile iron pipe
  • Instrumentation, lighting, HVAC, and plumbing

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