Shawinigan HDD

The Challenge

In 2018, the city of Shawinigan, Quebec was experiencing a period of growth. To accommodate this new population they needed to expand their water and sewer system. The plan was for a new 400mm water pipeline to be installed directly below the St. Maurice River, which is almost 1 kilometer wide.

The Solution

Horizontal directional drilling (HDD) is a minimal-impact trenchless method of installing underground utilities such as pipe, conduit, or cables in a relatively shallow arc or radius along a prescribed underground path using a surface-launched drilling rig. HDD offers significant environmental advantages over traditional cut and cover pipeline/utility installations. The technique is routinely used when conventional trenching or excavating is not practical or when minimal surface disturbance is required.

HDD is generally accomplished in three principle phases. First, a small diameter pilot hole is drilled along a directional path from one surface point to another. Next, the bore created during pilot hole drilling is enlarged to a diameter that will facilitate installation of the desired pipeline. Lastly, the pipeline is pulled into the enlarge hole, thus creating a continuous segment of pipe underground and exposed only at the two initial end points.

At over 1 kilometer, this project was a very long bore almost entirely through rock. Rock bores of that length require an experienced speciality contractor like Marathon Underground with the proper equipment, skilled operators and expert project managers to ensure the project is completed on time and on budget.