Record 4,800 LF Horizontal Directional Drill Completed Using 24" Fusible C-905® Pipe Beneath Lake Oahe in South Dakota
In August 2009, King Contracting of Lincoln, NE completed a record-breaking horizontal directional drill (HDD) of 4,800 LF of 24" Fusible C-905® pipe under Lake Oahe near Wakpala, SD. The HDD crossing was part of an 80-mile raw water transmission pipeline being constructed by the Standing Rock Rural Water Sioux Indian Tribe. The project also includes the construction of a new water treatment plant and water distribution system.
| Pipeline Details and Project Summary | |
|---|---|
| Project: | Raw Water Pipeline Phase 1, Contract 3-3 |
| Location: | Lake Oahe near Mobridge, SD |
| Owner: | Standing Rock Rural Water |
| Engineer: | Bartlett & West (Bismarck, ND office) |
| General Contractor: | S.J. Louis Construction, Inc. |
| HDD Contractor: | King Contracting Inc. (KCI) |
| Pipe: | 4,800 LF 24" DR18 Fusible C-905® |
| UGSI Contact: | Patrick Laidlaw, P.E.: (801) 699-2804 plaidlaw@undergroundsolutions.com |
Crossing Lake Oahe was one of the most challenging aspects of constructing the new transmission line due to the length and depth of the lake, which is formed by a large dam along the Missouri River just north of Pierre, SD. The original design called for a 3,660 LF HDD installation beneath one of the major tributaries of the lake. Due to a depth of nearly 100', the design required either 24" DR18 Fusible C-905® pipe or 30" DR7.3 HDPE to accommodate the earth load and provide similar hydraulic capability. Fusible C-905® pipe provided the lowercost, lower-risk option because it combined a smaller borehole with lower pipe weight (less than half of HDPE) and higher tensile strength. Four of five bidders (including the three low bidders) selected Fusible C-905® pipe.
When construction was set to commence, the lake level rose to more than 30 feet above the level of the previous season, requiring the drill length to be increased to 4,800 LF. Installing temporary culverts allowed the entire length of Fusible C-900® pipe to be fused together in a single string along Highway 1806. Pipe pullback took approximately 14 hours, with a maximum pull force of 220,000 lbs measured at the American Auger 625 drill rig. The line was successfully pressure tested to 235 psi two weeks following pull-in.
Jeremy King, President of King Contracting, commented: "The high tensile strength and smaller bore hole coupled with my comfort level with UGSI's fusion joint warranty were critical in going with Fusible PVC™ pipe."
Jerry Shae, Project Engineer with Bartlett & West, noted: "Fusible PVC™ pipe fit the need nicely for this project because it has a relatively narrow wall thickness yet it can be pressure-classed relatively highly. It also has favorable cost-savings when compared to other pipe options."
 Pipe Insertion |
 Fused Pipe Layout on Highway 1806 |
 Entry & Lake |