Southwest Distribution Project

​Construction

The distribution circuits will be installed using different installation methods based on the project terrain. This will include using a horizontal directional drill (HDD) to go under the North Saskatchewan River (marked in purple), an auger bore to cross under Anthony Henday Drive and Terwillegar Drive (marked in yellow) and an open cut trench method of construction for the duct bank (marked in light blue).

Horizontal Directional Drill (HDD)

The crossing under the North Saskatchewan River will be completed using a Horizontal Directional Drill (HDD) method of construction. The drill will be approximately 820 metres in length and be completed using the following steps:

1. Drilling a 25 centimetre pilot hole approximately 40 metres below the bottom of the river (see image 1).
2. Expanding the hole using a back reamer until the diameter of the hole reaches 1.2 metres (see image 2).
3. Pulling a 0.9 metre diameter steel liner pipe through the hole (see image 3).
4. Pulling a bundle of plastic pipes, which will contain the distribution circuits, into the steel liner pipe.
5. Filling the steel pipe with grout to stabilize the plastic bundle of pipes within the liner.

The process of installing both the steel liner pipe and the plastic bundle are time consuming activities and will require up to 36 hours of continuous work for each installation. This work will be noisy at times because large equipment is required to lift and move both the steel liner pipe and plastic bundle as they are installed underneath the river. The steel liner pipe and the plastic bundle will both be assembled within the municipal services area of the TUC prior to installation.

Directional bore hole/auger bore

A smaller direction drill called an auger bore will be used to cross under Anthony Henday Drive, Terwillegar Drive, and to install one distribution circuit south along Terwillegar Drive. It is a similar to the HDD process, just done on a smaller scale with a smaller pipe.

Open cut duct bank

For all other areas we will be installing the circuits in a duct bank. This will involve digging a 0.8 metre by 2.0 metre trench and placing the circuits in a concrete casing called a duct bank. Duct banks protect the distribution circuits from being damaged.

Environmental considerations

The environment is important to us and our construction practices have procedures in place to minimize potential impacts to the environment. For this project we have an Environmental Protection Plan in place to ensure proper environmental practices are followed. This includes full time environmental monitoring for the duration of the project and an archaeologist on site to monitor the HDD process.

Tree removal

To adhere to provincial and federal regulations regarding bird nesting season, we completed all the required tree removal in early April. This was done under the supervision of environmental experts.