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Phase 3 Project Details
Phase 3: Tunnels & Working Shafts

Update 14 July 2017
: In order to construct the Coming St access/retrieval shaft, the King St ramp from I-26 eastbound will be closed for the duration of the project, estimated to be July 2019.  
Click here for a link to the map showing alternate routes. 


  • Shaft construction and excavation continues at the Harmon Field shaft site and Coming St shaft site.  The tunnel excavation began on 10 July 2017.  
  • Complete work at Lockwood St Shaft Site:  February 2018
  • Substantial Completion:  June 2019
  • Final Completion: July 2019

Phase 3 of the US17 Spring/Fishburne Drainage Improvement Project will include the construction of deep tunnels and working shafts. There will be 4 working shafts constructed as part of this phase. Two of the shafts will be 20-ft internal diameter (Coming Street/King Street off-ramp and President St & Cannon St). The wetwell shaft between the Ashley River Bridges and the Harmon Field working shaft will be 30-ft internal diameter. The tunnel connecting the Coming Street shaft and wetwell shaft (under the Crosstown) will be approximately 5,400 LF (linear feet) in length and up to 12-ft in internal diameter. The tunnel connecting the Cannon St/President St and the Harmon Field shafts will be approximately 2,100 LF in length and a minimum of 8-ft in internal diameter. These tunnels will intersect approximately 140 feet below grade at the intersection of the Crosstown and President Street. There will also be a smaller 500 LF 8-ft diameter tunnel connecting the Cherry St drop shaft to the Crosstown tunnel. 

Note:  Completion of the work at the Lockwood St shaft site is significant as that will allow the commencement of Phase 4 of the project, construction of the wetwell and outfall.