Incorporation of Canadian RADAR data for historical event analysis

Karen Finney, Computational Hydraulics Int., Guelph, ON, Canada and David Blades, Halifax Water, Halifax, NS, Canada


Currently Halifax Water uses recorded rainfall from a network of tipping bucket raingauges to calibrate and validate wastewater, stormwater and combined sewer system models. Due to the inherent limited spatial coverage and intermittent operation, data from the raingauge network incorporates significant uncertainty. Environment Canada currently operates a network of 30 radar stations throughout Canada including Halifax, and makes data available on a subscription basis. Radar is investigated for supplementing raingauge data by providing more detail on the spatial distribution and movement of storm cells across water- and sewer-sheds.

PCSWMM, a spatial decision support system for wastewater, stormwater and watershed management modeling, has been used by Halifax Water for many years. The package includes comprehensive radar acquisition, processing and analysis capabilities for NOAA NEXRAD radar products. Radar functionality in PCSWMM includes: automatic bias removal against local raingauge data; spatial and temporal statistical analysis; area-weighted hyetograph generation; model input generation including spatial transposition of historical radar events; data management and editing tools; and radar rainfall visualization, animation and GIS output.

Existing radar systems are appraised, and the key differences between the Environment Canada radar and NOAA NEXRAD radar highlighted. Radar rainfall accuracy for the existing Halifax water raingauge network is then evaluated. Finally, ground-truthing methodologies are reviewed and the results compared against historical rain events.

 Click here to download a static PDF version of the presentation, with notes.

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