Under the River and Through the Woods
Prepared for the 2013 NC AWWA-WEA Annual Conference by Jacob VandenBosch, PE, McKim & Creed, Inc.; Mike Osborne, PE, McKim & Creed, Inc.; Rebecca Bowyer, PE, York County, SC
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Abstract
The York County Eastern Water System is located in the northeast corner of York County, SC north of the Catawba River. The water system is supplied through two sources: a connection to Charlotte Mecklenburg Utility Department (CMUD) to the north and the Rock Hill Water Treatment Plant (WTP) to the south. Prior to the completion of this project, finished water was conveyed to York County from Rock Hill through the Fort Mill water distribution system via a 24-inch pipe on a utility bridge spanning the Catawba River. During periods of peak demand, this supply feed was inefficient, and York County relied heavily upon the connection to CMUD.
The goal of this project was to construct a direct feed from the Rock Hill WTP to the Eastern Water System across the Catawba River with the capacity to meet the current and future demands of the system while remaining independent of the connections to CMUD and Fort Mill. The new water main would also provide redundancy to the water systems north of the Catawba River.
The design and construction of the project included approximately 33,600 lineal feet of 30-inch and 24-inch water main with a 12,000-gpm booster station. The water main was installed under the Catawba River by Horizontal Directional Drill (HDD) using approximately 1,000 lineal feet of 36-inch high-density polyethylene (HDPE). As a result of this project, York County will have the capacity to serve the projected demands of the Eastern Water System to the year 2030.
This paper outlines the background of the project and the problems faced by the Eastern Water System, present the determined solution, and provide a synopsis of the design and construction of the water main. Particular emphasis is placed upon the HDD crossing of the Catawba River, including choosing the location and method of the crossing, geotechnical conditions, general design, performed installation by the contractor, and lessons learned.