NWIC Upper Plateau Separation Project: Reducing Flood Risk through Innovative Storm Catchment Separation

The community of Sunnyside in Calgary, Alberta, is partially located within the Bow River floodplain. Sunnyside is protected from river flooding by an existing earth berm. The berm also prevents storm flows from being conveyed overland into the Bow River. Following a flood in 2013, the City of Calgary engaged Associated Engineering to complete a drainage study. It examined the drainage system within the community and recommended several drainage improvements. One of the improvements identified was a separate storm trunk to convey storm runoff by gravity, using an inverted siphon, from the Upper Plateau area directly to the Bow River. This new stormwater trunk intends to reduce the risk of stormwater surcharging in Sunnyside during elevated and low river level events on the Bow River. The proposed trunk, together with other improvements, reduces the risk and magnitude of overland flows, due to extreme rainfall events, from entering the community.