Municipal Surface Water Infrastructure (DNV)

Following a highly damaging debris flood on one of the steep urban creeks in North Vancouver, BGC conducted detailed studies of floods, debris floods and debris flows on over 35 creeks in North Vancouver. Most of the creeks flow through a complex stormwater drainage network in densely developed areas, where uncontrolled flows could cause extensive damage and potential loss of life. BGC estimated flow frequencies and magnitudes under consideration of climate change, which is projected to increase peak flows with higher volumes and intensities of rainstorms. Using principals of fluvial geomorphology, the shear stresses required to mobilize debris were determined for each creek and incorporated into assessments of culvert or bridge flow capacities and blockage potential. Based on numerical modelling of flow avulsion scenarios, BGC estimated economic and safety risks associated with hazard scenarios and developed risk control measures. The results of risk assessment will support the prioritization of expenditures and justify funding applications to implement the risk control measures. BGC developed an interactive, map-based web-application to communicate the results of the study, which greatly facilitated display of assessment results for individual components of DNV’s development infrastructure.