Discussion
Supporting North Vancouver’s wildlife and helping to drain neighbourhoods within the District and City, the Mackay and Mosquito Watersheds are essential local green infrastructure resources with important social and ecological value.
To protect and enhance these landmarks, Kerr Wood Leidal Consulting Engineers used PCSWMM to help implement an Integrated Stormwater Management Plan (ISMP); a challenging but vital goal for the local governments, residents and businesses that call these watersheds home.
PCSWMM was utilized to analyze existing watershed conditions, identify potential risks and create hydrologic/hydraulic models for current and future development land uses. Storm sewers and culverts were calibrated and verified with local precipitation and flow monitoring data from FlowWorks. Transects for the creek channels were created in PCSWMM using LiDAR data received.
Peak flows were estimated for all pipes and channels within the 10-, 100- and 200-year return period design storms using both climate change and existing Intensity-Duration-Frequency (IDF) curves. Due to the elevation difference in the Mackay and Mosquito Watersheds, there was a need to use PCSWMM to create multiple rain gauges at increasing elevations and apply them to catchments at different elevation bands.
Now complete, Kerr Wood Leidal and the City of North Vancouver were successful in meeting their modelling objectives – to assess the adequacy of the drainage system in safely conveying stormwater runoff, and to identify locations where there remain undersized culverts, bridge crossings and drainage pipes in order to inform future works.