Kiawah Island Utility Directionally Drills Water Main under Wetlands and Kiawah River

摘要

The existing Kiawah Island Utility (KIU) water system consists of one 16-inch ductile iron main installed in the late 1970s, connecting Kiawah Island to potable water provided by St. Johns Water Company on Johns Island, South Carolina. Over time, the exposure to the harsh salt environment hastened corrosion of the water supply line causing increasingly frequent leaks in the past several years. A major break would cut off the potable water supply and fire protection to Kiawah Island, prompting KIU to install a new 16-inch line.The new line was designed to connect from an existing 24-inch water main installed on Johns Island in 2007. That 2007 installation also included a 4,440-foot directional drill of 24-inch fused polyvinyl chloride pipe (FPVCP) under the Stono River. The new 16-inch redundant line crosses under the Kiawah River, then connects to the existing Down Island Pump Station on Kiawah Island. Ground conditions along the alignment required creek, river, pond, wetland, and marsh crossings, compelling KIU to directional drill multiple pipe segments, including a record-breaking 7,000-foot drill of 16-inch FPVCP water line under the Kiawah River.