Subaqueous Utility Crossing in South Carolina

When new SCDOT regulations made it impossible to reattach electrical conductors to the Keowee School Road bridge, our customer needed a new path forward. The existing distribution circuits serving the area had to cross Lake Keowee somehow, and with Blue Granite, one of the most challenging rock formations in the country, sitting beneath the surface, the answer was a 2,600 foot bore drilled 160 feet below the lake bed.

The scope was significant: install a 20″ HDPE casing housing nine 3″ conduits the full length of the bore, then pull over 16,000 feet of 750 KCMIL copper conductor through six of them. Infratech crews worked seven days a week on 12–16 hour shifts, navigating rock formations that slowed progress and generated substantial noise and vibration for the surrounding community, a neighborhood with a large retired population that needed to be brought along, not just notified. Infratech supervisors went door to door, set expectations, answered questions, and built sound barriers around the work zones before the first drill ever turned.

The project was expected to be a 12 month effort. Through constant customer collaboration, weekly reporting, and a team that knew how to adapt when the rock pushed back, Infratech brought it in on time and within budget. Three of the nine conduits were left empty, capacity built in for whatever comes next.

• 2,600 foot bore drilled 160 feet below Lake Keowee through Blue Granite rock
• 20″ HDPE casing installed housing nine 3″ inner-duct conduits
• Over 16,000 feet of 750 KCMIL copper conductor pulled through six conduits
• Three conduits left empty for future capacity
• Completed on time and within budget