Author(s): Colin Rennie, Jonathan Slaney
Linked Author(s): Colin Rennie
Keywords: River; Flood; Morphodynamics; ADcp; Spatially Distributed Depth Averaged Water Velocity;
Abstract: The city of Calgary is situated at the confluence of Bow River and Elbow River, both of which are wandering gravel-bed rivers. In June 2013 the catastrophic Alberta flood inundated the downtown core of Calgary. The flood caused five deaths, required evacuation of 100,000 people, and resulted in an unprecedented $5B-$6B in estimated damages. The flood caused extensive channel morphodynamic change due to mobilization of both bank and bed sediments. Pre- and post-flood bathymetric surveys of Bow River have been used to assess morphodynamic changes induced by the flood, which included extensive bank retreat and accumulation of new gravel bars upstream of flow obstructions such as bridges. These new gravel bars may exacerbate flooding during future events. Consequently, on the recession limb of the flood in September and October 2013, an extensive hydrodynamic survey of Bow River through Calgary was completed using an M9 acoustic Doppler current profiler (aDcp). This paper describes this data set. Aspects of particular interest include: distribution of flow around islands and mid-channel bars, flow acceleration in the vicinity of infrastructure, and secondary circulation in channel bends. The hydrodynamic data will be used to calibrate and validate morphodynamic numerical models of the reach, which will be used to assess various in-channel engineered mitigation flood works to minimize the consequences of future flood events.