The time distribution of rainfall is an important input to rainfall-runoff modelling and has a significant effect on the resulting peak discharge. At many facilities in the oil sands region of Alberta, the Natural Resources Conservation Service (NRCS) Type II design storm has typically been used for design of surface water management facilities. The appropriateness of the Type II design storm and several other time distributions was assessed by comparing the modelled peak runoff from the design storms with the modelled runoff from historical 24-h rainfall events in five small typical catchments. Results indicate that the NRCS Type II produces highly conservative runoff peaks compared to actual rainfall events at Fort McMurray, and a new synthetic design storm developed during the study more closely parallels the peak runoff produced by actual rainfall events.
Dick, W. and A. Ghavasieh. 2015 “A 24-h Design Storm for the Fort McMurray Region,” Canadian Journal of Civil Engineering, 42(10): 747-755.