Recent advances in flood frequency analysis

Research on flood frequency analysis has taken place with varying intensity over the last couple of decades. The eighties proved to be important years with many significant contributions, reviewed for instance by Greis 1983, Potter 1987, Kirby and Moss 1987, Cunnane 1987, NRC 1988, WMO 1989, and Bobée and Ashkar 1991. Due to its large economical and environmental impact, flood frequency analysis remains a subject of great importance and interest, and the research on improved methods for obtaining reliable flood estimates has continued into the nineties, although with different emphasis. In the seventies and eighties much effort was spent on developing efficient at‐site flood frequency procedures. New distributions and estimation methods were introduced in the hydrologic journals, some of them developed specifically for flood frequency analysis. It seems that this tendency has decelerated somewhat in the beginning of the nineties. Researchers are increasingly realizing that the lack of sufficiently long data series imposes an upper limit on the degree of sophistication that can reasonably be justified in at‐site flood frequency analysis. It has been emphasized by many that instead of developing new methodologies for flood frequency analysis, effort should be spent on comparing existing ones and on looking for other sources of information Potter , 1987; Bobée et al , 1993a. Regionalization is probably the most viable avenue for improving flood estimates, and fortunately this seems to be the direction that the research in flood frequency analysis has taken in the nineties.