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The southwest area of Edmonton has experienced a considerable amount of growth over the past few years. To accommodate this growth and meet the increased demand for electricity, we'll be installing new underground distribution circuits in the area. Distribution circuits carry electricity from substations to provide power to local homes and businesses.
Project overview

The route

This project will involve installing two new underground distribution circuits within the Transportation Utility Corridor (TUC) along the north side of Anthony Henday Drive from Maskêkosihk Trail to Rabbit Hill Road (map below.)

The new circuits will be located within the municipal services area of the TUC, which is on the north side of Anthony Henday Drive—approximately three metres from the residential property line. The TUC is an area designated by the Provincial Government for the location of roadways and utilities.

 

Distribution circuit configuration

The duct bank will have the capacity to hold a total of nine plastic pipes. Five of the plastic pipes will be used for distribution circuits. We plan to install two new distribution circuits now, while saving three for future growth in the area. The remaining four pipes will be used for fibre optic and communication cables.

 

Timeline
  • Phase 1 (north of North Saskatchewan River): trenching and duct bank construction, expected completion October 2019
  • Phase 2 (south of North Saskatchewan River to Terwillegar Drive): trenching and duct bank installation, completed September 2019
  • Phase 3 (Terwillegar Drive to Windermere Blvd): directional drilling, expected completion October 2019
  • Phase 4 (south of Terwillegar Drive to Rabbit Hill Road): trenching and duct bank construction, expected completion November 2019
  • Horizontal Directional Drill (under North Saskatchewan River): expected completion January 2020
  • In-service date: March 2020
Construction details

​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.

Construction impacts

​This work will create typical noise associated with construction. There will be two cases where the crew will need to work continuously for up to 36 hours in order to pull the steel liner pipe and plastic pipes underneath the river.

We will take measures to ensure we comply with the City of Edmonton’s Community Standards Bylaw for Noise Control. Should it be necessary to temporarily exceed acceptable noise levels or go past typical construction hours, we will work with the City of Edmonton to obtain the necessary permits.

Workspace

We are committed to public and employee safety.  All construction activities will be in accordance with City of Edmonton bylaws, Occupational Health & Safety requirements, and EPCOR’s strict health, safety and environment procedures and guidelines. The work area will be maintained in a safe and secure manner and fencing will be placed around all excavations and drilling sites.

Equipment

Equipment will include EPCOR vehicles, hydrovac trucks, barricades, fencing, a directional drill rig, backhoes, and other various construction equipment.

Site restoration

Grass areas will be re-seeded after the work is complete. For safety reasons, trees cannot be replanted on top or near the new duct bank as their roots could cause heat buildup and interfere with the functioning of the circuits.

Temporary access road/trail disruptions

A temporary access road (shown in a green dashed line on the map) will be required to allow vehicles to bring equipment to the drilling site. There may be a temporary closure of the trail path that will last up to one day to install the access road. If a trail closure is required, the date will be updated on our website and signs posted at the closure location.

During construction, there will be periodic disruptions to the trail path. Construction flaggers will be present to safely guide vehicles as they cross the path. 

Definitons

​Substations

Substations help convert electricity from higher voltage transmission lines to lower voltages, so it can be used by homes and businesses through distribution lines called circuits.

Distribution circuits

Distribution circuits carry lower voltage electricity from substations to provide power to local homes and businesses.

Duct banks

Duct Banks are used to contain pipes which contain multiple distribution circuits and protect them from being damaged.

Horizontal Directional Drill

Horizontal Directional Drills (HDD) use a surface drilling rig machine to install pipes in an arch underneath the ground. This is usually used to go underneath rivers or roads to minimize impacts  and disruptions.

Project open house

​Find out more information about this project by attending our open house.

 

Date: Tuesday, May 7, 2019
Time: 3:00 p.m. - 8:00 p.m.
Location: Terwillegar Community Church 1751 Towne Centre Blvd NW, Edmonton