Calgary Bow River Weir Project – Harvie Passage Preliminary Hydraulic Design & Physical Model Studies

CLIENT: Alberta Transportation

The proposed Calgary Bow River Weir Project – Harvie Passage on the Bow River in Calgary, Alberta, was intended to remove the existing safety hazard created by the weir, provide recreational opportunities and improve fish passage at the site, while maintaining the weir’s ability to divert water to the Western Irrigation District canal without increasing upstream flood levels.

NHC, as a sub-consultant to Golder Associates Ltd., conducted physical model studies for the preliminary design of the Harvie Passage. The main objectives of the studies were to observe and document hydraulic conditions near the modified weir and downstream channel and to refine the design of the channel features to provide a safe facility for recreational users and fish passage. A "comprehensive model" was constructed at a scale of 1:50 to provide an overall assessment of how the facility will perform, and a "flume model" was constructed at a larger scale to better understand flow characteristics at specific in-channel drop structures.

Model testing indicated that the preliminary design required improvement in several key areas. Recommended modifications developed in the models included: reducing the size of the low water channel entrance; creating three additional notches along the crest of the existing weir at the entrance to the high water channel; filling in the ogee weir apron; extending the sluiceway wall; optimizing the geometry of the divide island; modifying the layouts of the low and high water channels; refining the configuration and alignment of each drop structure; providing alternatives for fish passage at each structure; installing rock clusters to reduce recirculation with pools and provide resting areas; and, installing a berm along the right bank to emulate existing flow conditions.