The Nose Creek Watershed Partnership (NCWP) conducts watershed planning to protect riparian areas, improve stormwater management, and enhance water quality in the Nose Creek and West Nose Creek watersheds (collectively the Nose Creek Watershed), near Calgary, Alberta. In 2018, NCWP updated its watershed management plan and identified the need for a highly detailed hydraulic model of both creeks—incorporating over 140 km of stream channel and over 170 hydraulic structures—to evaluate plan implementation options across jurisdictions. The NCWP hired Barr to develop the model in HEC-RAS.
The highly meandered channels of both creeks presented challenges to using a purely one-dimensional (1D) model, so we coupled a 1D model of the channels with a two-dimensional (2D) model of the floodplains to accurately simulate both in-channel and overbank flow. To efficiently develop a set of closely spaced channel cross sections that achieved the level of detail desired by the NCWP, we created a GIS-based tool that automatically generated over 10,000 cross sections from a high-resolution bathymetric survey.
We supplemented the coupled 1D and 2D model with a fully 2D model from the same survey data, which allowed the NCWP to model both very low and very high flows. We calibrated the model using continuous discharge and water-level measurements from both creeks between 2019 and 2021, and we completed a sensitivity analysis on the channel and floodplain roughness.
This detailed hydraulic model will be used for a wide range of future watershed management efforts, including geomorphology assessments, stream and fish habitat restoration, and flood studies up to the approximate 1,000-year flood event.