West Ashley Transmission, Charleston, SC

Subaqueous Drilling in the Charleston Peninsula

Slated for completion in late 2018, the project scope generally consists of the design and construction of a water transmission main between North Charleston and West of the Ashley River. The project replaces a 24-inch waterline that was taken out of service approximately a decade ago due to persistent leaks. The project consists of extending approximately 15,067 LF of 36-inch diameter water main from the existing 24-inch diameter water main located along West Montague Avenue to the existing 36-inch diameter water main located along Hwy 61 and continue to the Bees Ferry Water Storage Facility in West Ashley – stretching approximately 2.8 miles total. Approximately 4,700 LF of the project consists of 36-inch steel waterline installed via HDD under the Ashley River from West Ashley to North Charleston and approximately 600 LF of steel casing was installed via jack & bore under major road ways and protected trees.

The new water line will improve reliability in the system and provide for future growth. Project features numerous design innovations, equipment and material selection such as:

  • Planning for the future; design provisions for growth in West Ashley; short and long-term utility goal identification;
  • Selection of eco-sensitive materials;
  • Environmental and public considerations/impacts, river and wetlands; accountability;
  • Resiliency measures; impressed current cathodic protection system and accountability meter vault, redundancy between North Charleston and West Ashley;
  • Public outreach/communication; traffic/road closures, utility impacts, etc.; and
  • Subaqueous drilling in a coastal community.

AECOM, in association with Hussey Gay Bell, provided engineering design, plan preparation, permitting, assisted with easement acquisition, pre-qualifying contractors, bidding, award, and construction administration and observation.

West Ashley Transmission
Charleston, SC

To enhance fire protection and adequately handle growth-related demand for water resources in the increasingly populated West Ashley Area, Charleston Water System elected to install a 36-inch diameter transmission main across the Ashley River – one of the most traveled rivers in the region – via horizontal directional drilling to minimize ecological impacts to the river and marsh. Stretching approximately 2.8 miles, from near the corner of Montague Avenue and Dorchester Road in North Charleston, to near the intersection of Ashley River Road and Bees Ferry Road in West Ashley, the new waterline increases resiliency for the region through its impressed current cathodic protection system and accountability meter vault, providing redundancy between North Charleston and West Ashley.