British Columbia Regional Flood Frequency Analysis Web Application

This ArcGIS Online application displays the hydrometric stations and accompanying drainage areas analyzed as part of Bulletin 2020-1-RFFA described below. A frequency analysis was conducted on Annual Maximum Series (AMS) streamflow data collected at Water Survey of Canada (WSC) and United States Geological Survey (USGS) hydrometric gauge stations that met the following criteria for inclusion in the Bulletin 2020-1-RFFA study: at least 10 years or data (with 350 or more days of observations) above the low outlier threshold; less than 20% (by basin drainage area) regulation; a corresponding basin polygon dataset (either supplied or delineated) with an area <15% different than the basin area reported by WSC or USGS; full metadata coverage for the basin (e.g. mean annual precipitation, elevation, etc.); and 1-, 3-, 5-, and -10 day distribution fits that did not overlap for any Average Recurrence Interval’s (ARI) above 2 years. The analysis was conducted by Northwest Hydraulic Consultants and RTI International Inc. for the Water Management Branch of FLNRORD. The geographic area of the dataset is shown in Bulletin 2020-1-RFFA and consists of all of British Columbia and selected watersheds around the perimeter of the province. There are 3 datasets within this project consisting of: • Hydrometric station locations of the stations that were analyzed as part of the study. • The drainage areas of the respective hydrometric stations that were analyzed. • The BC Hydrologic Zones that were extended outside of BC.