Phase 4 of US 17 Spring/Fishburne Drainage Improvements Completed

Davis & Floyd recently completed Phase 4 of US 17 Spring/Fishburne Drainage Improvements in Charleston, South Carolina. This phase included the construction of the outfall and wetwell. The 500’-long outfall releases into the Ashley River with a design ensuring no erosion and will be hidden below low tide. A cofferdam was installed for outfall construction and a pump station installation for the final phase.

Construction was completed of the 135’ x 55’ wetwell, 40’ below grade, consisting of cast-in-place concrete and structural steel framing, to house three 66” diesel pumps. Once fully functional, these three diesel pumps will be capable of pumping water 360,000 gallons per minute. Installation also included dewatering pumps, tunnel drain pumps, silt pumps, sump agitation pumps, mechanical bar screens, conveyors, and flap gates. A total of 8,000 cubic yards of concrete were placed in this project phase.

Though several milestones of construction were achieved, Phase 4 under $50 million rather than the original budget of $65.3 million.

Phase 5, which will soon begin, includes completing the pump as well as engine installation of the diesel engines and fuel system.

The building to house the pumps along with mechanical and electrical components will also be completed. This drainage system will serve approximately 500 acres (20%) of peninsular Charleston and drastically reduce flooding.