Courbes intensité-durée-fréquence des précipitations à Yangambi, Congo, au moyen de différents modèles de type Montana

Abstract

Intensity-duration-frequency (IDF) curves are established for precipitation at the Yangambi station located in the tropical zone of Congo. Various models of Montana type were tested for durations varying between 15 min and 24 h. These empirical formulas were selected because they are advocated in the French guide for urban drainage systems and therefore engineering consultancies working on development projects in tropical Africa are interested in that information. The advantages and disadvantages of the different Montana type formulas are discussed. In particular, it is noted that the so-called classical Montana formulas should be rejected in favour of a more physically and probabilistically sound formula. The final choice was made on a family of parallel curves containing only four parameters to be estimated. The lack of data for the extreme values of precipitation for short durations (less than 24 h) and of sufficiently long reference periods with regard to tropical Africa stresses the importance of this study. Copyright © 2006 IAHS Press.