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Project Phasing
Project Phasing


Phase 1 (COMPLETED):
  With the completion of the first phase of the project (TIGER 1), significant improvements have been made to pedestrian safety, vehicular safety, and traffic efficiency along and directly adjacent to the Septima Clark Parkway from Spring St to Coming St.  While more than 175 stormwater structures and 5,500 linear feet of pipe ranging from 18-in diameter to 48-in diameter have been installed in this same stretch of roadway, significant work still needs to be completed before the drainage problems can be more fully alleviated.  Additional phases are planned with project completion estimated for 2023. 

Phase 2 (COMPLETED):  Additional work on Spring and Cannon Streets from the western terminus of Phase 1 to Lockwood Blvd, President St south of the Crosstown to Cannon St, President St north of the Crosstown to Fishburne St, Fishburne St from Harmon Field to Ashley Ave, and Ashley Ave from Fishburne St to Sumter St.  More than 12,000 LF of new stormwater pipe ranging in size from 15-in to 54-in and more than 300 stormwater structures (catch basins, inlets, junction boxes, conflict structures, etc.) were installed.  Eight drop shafts with vortex boxes were also constructed during this phase that connect to the deep tunnel system (Phase 3).  Crowder Construction Company (Charlotte, NC) began work on 1 June 2015 and completed this phase of the project on 20 December 2017. 

Phase 3 (underway):  This phase will see the construction of 8,232 linear feet of 12-ft diameter tunnel up to 150-ft below the ground surface, two 30-ft diameter working shafts, and two 20-ft diameter exit shafts.  The main line tunnel is approximately 1 mile long running east-west under US17 from between the Ashley River bridges to Coming St.  The President St tunnel is approximately 1/2 mile north-south running under President St from Harmon Field to Cannon Street and intersecting the main line tunnel more than 140 feet below the intersection of US17 and President St.  Jay Dee Construction, Inc. out of Livonia, MI mobilized in early July 2016 and is expected to complete this phase by July 2019.   
Phase 4:  Construction of the wet well for the large stormwater pumps and the triple box culvert outfall into the Ashley River.  With completion of Phase 4 of the project, some drainage improvements should be realized.  It is estimated that construction for Phase 4 will begin in  fall of 2018 (depending on when the Crosstown tunnel is complete and Jay Dee has demobilized from the Ashley River Bridges site) and be completed in 2022.

Phase 5:  A new pump station between the Ashley River Bridges with three pumps each capable of pumping 120,000 gallons per minute, three 850 h.p. diesel engines to power the pumps (thereby eliminating the need for electricity to run the pumps in the event of a power failure), and one back-up diesel generator to run the electrical and control systems in the event of a power failure.  Once Phase 5 is complete and the pump station is on-line, the Crosstown and surrounding areas should remain passable in all but the very worst storm events.  (Due to the topography and layout of the City of Charleston, the pump station will not be able to accommodate tropical storm events with storm surge that inundates the City.)  It is estimated that construction for the pump station will begin at the completion of Phase 4 (2022) and be brought on-line sometime in 2023. 

Steven A. Kirk, P.E.
Senior Engineering Project Manager

2 George Street
Suite 2100
Charleston, SC 29401

Ph: 843-579-7682
Fx: 843-973-7261