REGIONAL RAINFALL DISTRIBUTION FOR CANADA

Current point rainfall frequency analysis techniques used in engineeri ng design are outdated. In this study, data distribution and analytica l techniques are reviewed, and a new method for regional analysis of r ainfall is presented. The regional analysis is performed using data ac ross Canada, and takes advantage of recently developed linear order st atistics of L-moments. Numerical analysis of 320 stations showed that Canada may be considered as one homogeneous region with respect to L-s kewness and L-kurtosis, However, the L-coefficient of variation shows regional variability that is related to the mean annual precipitation (MAP). A regional parent distribution is identified as the general ext reme value (GEV), with parameters depending on MAP and storm duration. These findings differ from present methodology, whereby the Gumbel I distribution is used irrespective of storm duration.