| Abstract | The West Timiskaming Dam (Ontario Dam) spans the Ottawa River from the south end of Long Sault Island to the west bank of the river. On the other side of Long Sault Island, slightly further upstream another dam exists (East Dam or Quebec Dam) that spans from the north end of the island to the east bank of the river. The East and West Dams at Timiskaming control the water level in the upstream body of water, known as Lake Timiskaming. The West Dam was completely replaced with a new structure in 2017 and since its completion, the Ottawa River has experienced a large flow event during the spring of 2019. There was concern that scour of the newly placed downstream riprap may have occurred during this large flow event. In order to investigate the hydrodynamic conditions at the West Dam and potential scour of the downstream riprap, a three-dimensional physical model of the West Timiskaming Dam structure, riprap protection, and portions of the upstream and downstream river bathymetry was designed and constructed at a geometric scale of 1:24 in NRC’s research laboratory located in Ottawa, Canada. The model was used to simulate a large number of historic dam conditions including flows, sluice settings and tailwater elevations to investigate the cause of riprap scour downstream of the dam structure. In addition, the model was used to test various options to mitigate future scour potential. |
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