York Durham Sewage System Forcemain Twinning Project (York Region Contract No. T-18-131)

The York Durham Sewage System (YDSS) was originally built in the 1980s as a single forcemain by the Province of Ontario and its ownership was subsequently transferred to the Regional Municipality of York in the 1990s. Local sewer systems throughout the Town of Newmarket (located in York Region) connect to the YDSS which then conveys effluent to the Duffin Creek treatment plant located approximately 60 kilometers (km) to the south. In 2016, York Region’s water and wastewater master plan identified that the YDSS was reaching capacity in the Town of Newmarket and required an upgrade. The resulting forcemain twinning project included the addition of a secondary forcemain. This upgrade was challenging as the new forcemain had to be installed through a dense urban environment and a floodplain of the East Holland River which runs north to south through Newmarket. Microtunneling installation of the 5.5 km long forcemain through Newmarket required 11 river crossings, 3 railway crossings, numerous street crossings, and work within and below city parks. The forcemain was installed in two passes. For the first pass, full face slurry microtunnel boring machines (MTBM) were used to install precast microtunnel pipe (casing pipe), manufactured to CAN/CSA A257.2 (ASTM C76). For the second pass, AWWA C301(E) prestressed concrete cylinder pipe (PCCP) was used as the carrier pipe and was installed and grouted in place within the casing pipe.