Work activities during water construction projects

​Micro-tunneling

Micro-Tunneling is a method used to construct new drainage sewer tunnels. First a large shaft (about 9-12 metres in diameter) is built which will facilitate lowering of a Tunnel Boring Machine (TBM) into the ground. The TBM then grinds through soil and other ground conditions underground along the alignment of the new tunnel. Pipe is then installed behind the micro-tunneling machine to create the tunnel.

The tunneling process occurs underground; however, shafts are required along the alignment and placed in engineered distances at start and end points (used to retrieve or turn the TBM). During tunneling, it may appear not much work is occurring; however, this is being done underground.

Due to the size of the shaft locations, impacts usually include road/sidewalk closures.

​Open trench construction / excavation

Open trench construction is a method in which surface area is excavated to install new infrastructure. Most of the work for this project will include this type of construction, including the installation of underground power infrastructure and water main relocations.

Because open trench construction requires a large trenched area, impacts usually include road and/or sidewalk closures. Due to the amount of material required, there is often a laydown area that needs to be incorporated onto the site, which may cause a large portion of a road and/or sidewalk to be closed, or disrupt a greenspace area which may be used for public recreation.