Markham PD6 Water Supply

Client: Regional Municipality of York
Services: Environmental Assessment and Route Selection, Preliminary Design Report, Detailed Design, Contract Administration and Resident Inspection, Post-Construction Services

Key Features:

• 6km of 1050 mm Concrete Pressure Pipe Watermain on McCowan Road from Major MacKenzie Drive to Stouffville Road in the Towns of Markham and Whitchurch-Stouffville.
• The project included 11 valve chambers (6 line valves, 2 line/branch chambers and 3 air release valves), two connections to the local water system, and two high pressure gas pipeline crossings.
• Five major creek crossings (Little Rouge River and Bruce Creek), with “Jack and bore” tunneling used at two creek crossings, including a 6m culvert at Berczy Creek

York Region’s Long Term Water Master Plan update identified the PD6 McCowan Road Watermain and the North Markham PD6 Reservoir, as priority projects to serve the planned growth in north Markham and Whitchurch-Stouffville.

The Class EA process included route selection and the evaluation of alternative designs, alignments, construction methods (e.g. tunnel vs open cut etc.) as well as potential impacts and mitigative measures.

The project also involved a hydrogeological assessment and extensive dewatering to prevent unstable trench conditions in high water table areas. Monitoring and special measures were necessary to ensure private water (well) supplies and the nearby Robinson Wetland Complex (west side of McCowan Road) were not adversely affected.

Watermain construction was coordinated and staged simultaneously with the new reservoir construction as part of a combined project.