Coldwater River Flood Frequency-Magnitude Study

BGC was engaged to complete floodplain mapping and steep creek geohazards assessments in the Regional District of Central Kootenay. Regional flood frequency and statistical trends analyses were completed as part of this work. Climate change was accounted for using a statistical analysis to inform expected conditions, which identified a need for hydrological modelling. Flood depth, velocity and intensity maps for the 20-, 50-, 100-, 200- and 500- year return period events were produced, as well as mapping of the 200-year flood level plus freeboard allowances and channel change mapping based on topographic features. Climate projections were used as input parameters in the modelling of flooding conditions, and BGC subsequently incorporated flood extents and conditions in the assessment of the steep creek hazards.