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. The project will enhance public safety and reduce potential future flood damages by identifying and quantifying river flood hazards.

The main project tasks encompass: 1) survey and base data collection; 2) open water hydrology assessment; 3) hydraulic model creation and calibration; 4) open water flood inundation map production; 5) open water flood hazard identification; 6) governing flood hazard map production; 7) flood risk assessment and inventory; 8) channel stability investigation; and 9) digital study file compilation.

Channel cross section and bridge structure surveys were completed between June and October 2018 to provide detailed terrain data in support of the analysis and mapping. Naturalized flow and regulated flow routing scenarios were developed as part of the open water hydrology assessment. Flood frequencies have been estimated on natural and regulated flows for the 2-, 5-, 10-, 20-, 35-, 50-, 75-, 100-, 200-, 350-, 500-, 750-, and 1000-year events. A HEC-RAS numerical model was developed and calibrated to support inundation mapping, river hazard assessment, and floodway determination. The mapping will guide future development along the study reaches and assist local officials with flood emergency response planning.