PRESENTATION AND REVIEW OF SOME METHODS FOR REGIONAL FLOOD FREQUENCY-ANALYSIS

Regional flood frequency analysis is used for the estimation of floods at sites where little or no data are available. It involves the ident ification of groups (or regions) of hydrologically homogeneous catchme nts and the application of a regional estimation method in the identif ied homogeneous region. The main objective of this study is to systema tically compare various regional flood estimation procedures with spec ial emphasis on data from the two Canadian provinces, Quebec and Ontar io. Four methods for delineating homogeneous regions and seven regiona l estimation methods were investigated and these methods are described here. The project was specifically aimed at developing new regional e stimation techniques (or combinations of techniques) and to improve ex isting methods. Special emphasis has been put on non-parametric method s as an alternative to classical parametric techniques. The use of par tial duration series data in a regional context has also been thorough ly explored. An accompanying paper (GREHYS, 1996, J. Hydrol., 186: 85- 103) provides a detailed description of the inter-comparison approache s and of the results obtained in the study.