Water Quality and Sediment Behaviour of the Future: Predictions for the
21st Century (Proceedings of Symposium HS2005 at IUGG2007, Perugia, July
2007). IAHS Publ. 314, 2007, 20-27
Modelling
extreme suspended sediment concentrations in North America: frequency analysis
and correlations with watershed characteristics
YVES
TRAMBLAY, André Saint-Hilaire & Taha B. M. J. Ouarda
INRS-ETE, 490 rue de la Couronne, Québec, Québec
G1A9A9, Canada
yves.tramblay@ete.inrs.ca
Abstract Suspended sediment concentration (SSC) is an important abiotic variable for river habitats. Inspired by the statistical methods developed for flood frequency analysis, the probabilistic approach adopted in this paper is used to quantify extreme SSC events. Probability distributions were fitted to 149 series of annual maxima of SSC in Canada and the USA in order to estimate quantiles of SSC for different return periods. The most adequate probability distributions for modelling extreme events of SSC were selected based on the Bayesian information criteria. Seasonal patterns of occurrence of extreme concentrations were also analysed. Then, in order to investigate the links between magnitude of extreme SSC and drainage basin characteristics, correlations between annual maximum SSC, discharge, and a large range of physiographic variables were calculated, and the most significant ones were highlighted.
Key
words extremes;
frequency analysis; physiographic influences; suspended sediment concentrations