Abstract Manager

Range Line Road is a two-lane road located in a residential area in the Town of Ajax, Ontario. Under existing conditions, it has a rural cross section on the west portion and an urbanized cross section on the east. Stormwater runoff drains toward Lake Ontario carried by ditches and culverts in the rural west portion, and by storm sewers in the urbanized east. With Carruthers Creek to the north and Lake Ontario to the south, a section of the road is within Toronto and Region Conservation Authority’s (TRCA) regulatory floodplain limit. Consultation with TRCA and local residents reveal that water from Lake Ontario can overtop Range Line Road during heavy rainfalls. Site investigations show there is minimal slope in the existing ditches and that groundwater levels are high. This is evident from culverts heaving up and cracking in the existing pavement along Range Line Road and adjacent driveways.

After consultation with the public the Town reaffirmed their decision to rehabilitate the road pavement and to extend the existing sidewalk on Range Line Road through the rural west section as part of their ongoing effort to improve road safety and active transportation network connectivity. The sidewalk extension will fill in the existing ditches to minimize grading impacts onto adjacent residential properties. Normally, storm flows drained by gravity sewers would be proposed but this will not work here because of the limited ground cover available due to the minimal difference in elevation between the road and the lake. Without a viable drainage system to drain water away from the road, the new pavement will not reach its expected service life and the new culverts will continue to heave up against the new pavement.

Through extensive collaboration with the Town and a well-known manufacturer, the project team delivered a design that achieved the Town’s objective in extending the sidewalk while utilizing a unique slot-drain system along the new curb and gutter in lieu of the conventional stormsewer and catchbasin system to facilitate drainage and thus improve the new pavement’s chances of reaching its expected service life. While the same product has been used before on one of MTO’s Highway 401 projects, the Town of Ajax is one of the first municipalities in Ontario to use it on their roads. Main design challenges include demonstrating the product’s durability, constructability, and maintenance effort to Town’s Road Operations. All construction work was completed in December 2023.