This project is located along an estimated 370 metre-long stretch of German Mills Creek, within German Mills Settlers Park. The project area is situated west of Don Mills Road between John Street and Steeles Avenue East, in the City of Markham. A York Region sanitary sewer line and the Lake to Lake multiuse trail run parallel to the east bank of the watercourse in the park. In some places, the sanitary line also crosses the watercourse.

The Leslie Collector sanitary sewer was installed within German Mills Settlers Park in 1970. Since then, German Mills Creek naturally migrated within the floodplain. The creek has eroded its banks and shifted close to, or over top of, the sanitary sewer in places. As a result, the sewer is now at risk of exposure in six distinct locations in the park.

In 2018, TRCA began a Schedule B Municipal Class Environmental Assessment for Water and Wastewater Projects. Greck was retained to assess three alternative solutions to protect the sanitary sewer infrastructure. The public was consultated as part of a A Municipal Class Environmental Assessment (MCEA).

Once the preffered alternative was chosen, Greck prepared the necessary design drawings and overseed construction to realign the watercourse to a historical channel alignment, which is further from the sewer and trail. Different types of bank protection were provided including, vegetated stone revetments, live staking plants directly in the bank, brush layering, and reconstruction of an existing armourstone wall. Additionally, habitat features for native wildlife were incorporated including woody debris which provides cover for aquatic species. Two oxbow wetlands will also be connected to the watercourse, of which one will be newly created.

Replacement of the old crossing with a new 30 metre pedestrian bridge was also included as part of the project. A portion of the recreational trail will be realigned to meet the new bridge.

Corbett Creek Watershed Study and Floodplain Mapping

Oshawa