The City of Edmonton as improved the level of flood protection in the Prince Rupert neighbourhood in north-central Edmonton by constructing a stormwater management facility, new storm sewers, and catchbasin improvements. The Prince Rupert SWMF is located at Prince Rupert Elementary School Park with a dry pond incorperating an LID bioretention feature.

Sameng was retained by the City of Edmonton in 2013 to provide preliminary design, detailed design, tender services, general engineering during construction, and project commissioning for the project. The project also involved geotechnical engineering by Thurber Engineering, landscape architecture work by EDA Consulting Inc., stakeholder meetings and public consultations, and a risk assessment, value engineering and constructability workshop.

For this project, Sameng developed a detailed combined stormwater and sanitary model using Mike Urban. Sameng constructed a new computer model using the most up-to-date trunk models and local pipe information from the City’s DRAINS database. Sameng built the model to include a coupled minor system (sewers) and major system (surface drainage). The integration of surface drainage flows allowed the model to provide a more accurate representation of the surface flooding mechanism and sewer flows during large rainfall events.

Using the detailed computer model, Sameng made improvement recommendations on the conceptual design to provide flood protection for a greater number of residences in the neighbourhood. The proposed design included the cost-effective use of catchbasin flow restrictors to direct flow towards newly installed storm sewers and prevent surcharge in the existing combined sewers. Simulation results of the improved system show a minimum 1-in-100 year level of flood protection throughout the study area. A catchbasin improvement plan was also developed for the area, to allow capture of the 100 year event into the new storm sewers and into the SWMF.

he project team worked with the City of Edmonton to design a LID bioswale design at the bottom of the SWMF, from the inlets to the outlet. This would provide low-flow conveyance and quality treatment for some of the new storm sewers in the neighbourhood. The pond acts as a storage facility during larger events.

Construction of the Prince Rupert SWMF located at Prince Rupert Elementary School Park concluded in Fall of 2015. The completed construction of the SWMF with LID bioswale feature, installed seperated strom sewer from the combined storm and sanitary sewers and installation of the recommended catch basin flow restrictures will together mitigate any future flooding in the Prince Rupert neighbourhood.