The evaluation of a two-dimensional sediment transport and bed morphology model based on the Seymour River

The purpose of this study was to provide an evaluation of the performance of R2DM using a mountainous stream reach with a complex geometry and coarse substrate. R2DM is a two-dimensional sediment transport and bed morphology model which was developed at the University of British Columbia and programmed within River2D. Bed morphology changes were modelled over a series of high flow events which occurred on the Seymour River in North Vancouver, British Columbia during the winter of 2008/2009. The model was evaluated based on its ability to simulate the overall and local bed changes by comparing the modelled results to the surveys of the pre- and post-storm ground elevations. The model displayed erosion in high bed shear stress areas and deposition in low bed shear stress areas and was able to display general bed changes through the site. R2DM was also tested as a design tool looking at bank protection using various riprap orientations through the same study reach. As a design tool R2DM showed favourable results. In addition to evaluating the R2DM as a sediment transport and bed morphology model, the instream works through the study reach were also assessed. Instream works were installed to improve the physical habitat for fish by decreasing velocities and increasing depths through the site. Comparing the pre- and post-project works an increase in physical habitat availability was found through the two-dimensional simulations. A second evaluation of the habitat was also completed examining the morphological changes which took place at the site. Sediment transport is an important consideration in habitat improvement projects due to the impacts that the instream structures can have on the sediment transport but also the effects that sediment transport can have on the instream structures. River2D along with R2DM can provide a means of evaluating river restoration works by combining hydrodynamic, morphological and habitat simulations into one model.Applied Science, Faculty ofCivil Engineering, Department ofGraduat