Alberta Environment and Protected Areas retained NHC in September 2022 to complete a flood study for the town of Stettler and adjacent areas of Stettler County. The study area includes a 30 km reach of Redwillow Creek, and a 4 km reach of Unnamed Tributary.

The study is conducted according to Flood Hazard Identification Program Guidelines, incorporating technical changes implemented in 2021 regarding how floodways are mapped in Alberta. The overall objectives of the study are to enhance public safety and to reduce potential future flood damages and disaster assistance costs.

The study is comprised of five major project components: Survey and Base Data Collection, Open Water Hydrology Assessment, Open Water Hydraulic Modelling, Open Water Flood Inundation Mapping, and Design Flood Hazard Mapping.

Flood frequencies with various return periods were determined through the regional hydrology assessment. A 1D hydraulic model will be developed with the survey data and DTM. The model will be used to simulate a total of 13 flood scenarios, and flood inundation maps will be subsequently created for the 2-, 5-, 10-, 20-, 35-, 50-, 75-, 100-, 200-, 350-, 500-, 750-, and 1000-year events. The results will be used to delineate the floodway and flood fringe boundaries and to create floodway criteria/flood hazard maps.