Dr. Trevor Dickinson, Professor Emeritus University of Guelph presented his work with Ramesh Rudra and Kishor Panjabi, Water Resources Engineering, University of Guelph to the Southern Ontario Stormwater Discussion Group at its September 27, 2018 meeting in Brantford, Ontario. The presentation shows the effects of climate on streamflows in southern Ontario including lower spring flow volumes and rates, and the effects of urbanization on streamflows including higher spring and summer flows. The distribution of flooding events through the years is reviewed, showing fewer spring and more summer period flood events. Climate change appears to increase winter runoff volumes due to higher temperatures which reduce spring volumes and peaks, a decrease in flood risk.