Immediately during and after the August 4th, 2014 Storm event, Conservation Halton Staff conducted field investigations in areas of the City of Burlington affected by riverine (creek-based) flooding to document damages and the extent of flooding. It is very important to understand how the watershed responds during a severe storm event in order to guide future development and improve flood plain management. Our most important finding, with further details in the Flood Report, is that the areas, in the City of Burlington, where Provincial and Conservation Halton flood plain planning policies were applied, were the least affected during the August 4th, 2014 Storm event. These areas experienced the least amount of erosion and flood damage in comparison to areas of the City of Burlington that were developed before these policies were put into place.
The August 4th Storm is considered a severe weather event and was an unprecedented storm for this area: instead of the usual broad-based rainfall pattern, the storm cells followed one another in series over a single, narrow area (a phenomenon called ‘training’). Even though the storm is uncommon in the City of Burlington, our flood plain models and projected flood plain limits were quite accurate.
Conservation Halton, in association with the Environmental Water Resources Group (EWRG) Limited, has completed a report on the August 4th, 2014 Storm Event. The focus of the report includes the following areas:
Staff used rain gauge information to calibrate radar data from the Buffalo NEXRAD radar station to provide an estimate of rainfall totals and refine rainfall distribution to paint an overall picture of the storm. Additionally, the storm’s rainfall totals were compared to statistical rainfall data to provide an idea of the magnitude of the storm (e.g. greater or less than a 100 year event).
Flood Damage Characterization
Conservation Halton staff surveyed the hardest hit creek systems during the week following the August 4th, 2014 storm to document observed and/or reported riverine (creek-based) flood damages for each watercourse. The focus of this work was to assess flooding impacts to creek and flood plain areas (as per our mandate) and does not include flooding associated with storm water (from roadways, ditches, etc.) or sanitary sewer backup as these flood impacts are being assessed by the Region of Halton and the City of Burlington.
Conservation Halton staff used the field data collected (e.g. debris lines and high water marks) to estimate flows experienced in the creek and flood plain areas to better understand how the watershed responded to the August 4th, 2014 storm event. This information allows staff to refine our flood plain models that leads to better flood plain management.
The report concludes with a number of recommendations to potentially mitigate the impacts of creek based flooding for future flood events. The recommendations will be implemented in partnership with the Region of Halton and the City of Burlington.
Flood Reports and Studies
The City of Burlington has a page on their website which compiles the various flood reports and studies related to the August 4, 2014 flood. Click here to vist the Flood Reports and Studies page on the City of Burlington website.