NHC was retained by Alberta Environment and Parks to conduct a flood hazard study along the North Saskatchewan River including the Town of Devon, the City of Edmonton, and the town of Fort Saskatchewan. The reach consists of 111 km beginning upstream of the western edge of 32-50-26-W4 to the eastern edge of 35-56-21-W4, including portions of Whitemud Creek and Sturgeon River. As the North Saskatchewan River flow is regulated by the Bighorn and Brazeau Dam upstream, the objective of this work was to provide open water flood frequency estimates for the study reach under both natural (unregulated) and regulated conditions.

This component of the main project includes: 1) a description of the hydrologic characteristics of the study area; 2) naturalization of flows; 3) routing of naturalized and regulated flows; 4) flood frequency analysis for both natural and regulated flood peaks; and 5) a commentary on the effects of climate change on the flood regime.

Naturalization of flows included the analysis of flows through two major storage projects, including: Lake Abraham and Brazeau Reservoir. The flow routing analysis was performed using the Streamflow Synthesis and Reservoir Regulation (SSARR) method and HEC-ResSim. The resulting naturalized flow and regulated flow scenarios were critical components of the North Saskatchewan River Hazard Study project.