The City of Edmonton has improving the level of flood protection in the Duggan neighbourhood in south-central Edmonton by constructing a stormwater management facility and corresponding sewer upgrades. The Duggan SWMF is located at Charles Anderson Park. The improvements should improve the level of service to a 1:100 year rainfall event in the vicinity of the facility.

Sameng was retained by the City of Edmonton in 2012 to provide preliminary design, detailed design, contractor procurement, general engineering during construction and project commissioning of these components. The project also involve geotechnical

engineering by Thurber Engineering, landscaping design by EDA Collaborative Ltd., value engineering and risk assessments, as well as stakeholder meetings and public consultations. Detailed design of the project was completed in 2013.

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

Sameng made improvement recommendations that would reduce construction costs and provide an additional level of flood protection compared to the previous conceptual validation study. Furthermore, Sameng developed a cost-benefiting conveyance improvement that would see flooding to the northeast of the neighbourhood reduced significantly; an area that saw several flood reports in the past. Simulation results of the improved system shows a minimum 1-in-100 year level of flood protection in the vicinity of the SWMF. A catchbasin improvement plan was also developed for the area, to allow capture of the 100 year flood event.

After a public consultation, which a majority of residents were in favour of a naturalized landscaping design concept, our project team designed a LID bioswale design at the bottom of the SWMF, from the inlets to the outlet. This would provide low-flow conveyance of some reconnected catchbasins to the facility and provide quality enhancement. The pond would act as a surge pond during larger events.

Construction of the Duggan SWMF located at Charles Anderson Park concluded in Fall of 2015. The completed construction of the SWMF with LID bioswale feature, newly installed storm sewers and recommended catch basin improvements will together mitigate any future flooding in the Duggan neighbourhood.