Estimation of local extreme suspended sediment concentrations in California Rivers.
The total amount of suspended sediment load carried by a stream during a year is usually transported during one or several extreme events related to high river flow and intense rainfall, leading to very high suspended sediment concentrations (SSCs). In this study quantiles of SSC derived from annual maximums and the 99th percentile of SSC series are considered to be estimated locally in a site-specific approach using regional information. Analyses of relationships between physiographic characteristics and the selected indicators were undertaken using the localities of 5-km radius draining of each sampling site. Multiple regression models were built to test the regional estimation for these indicators of suspended sediment transport. To assess the accuracy of the estimates, a Jack-Knife re-sampling procedure was used to compute the relative bias and root mean square error of the models. Results show that for the 19 stations considered in California, the extreme SSCs can be estimated with 40-60% uncertainty, depending on the presence of flow regulation in the basin. This modelling approach is likely to prove functional in other Mediterranean climate watersheds since they appear useful in California, where geologic, climatic, physiographic, and land-use conditions are highly variable.
Tramblay
Yves
Y
Chair in Statistical Hydrology, INRS-ETE, 490 rue de la couronne, Québec, Canada G1K9A9. ytramblay@gmail.com
Saint-Hilaire
André
A
Ouarda
Taha B M J
TB
Moatar
Florentina
F
Hecht
Barry
B
D002140:California; D004784:Environmental Monitoring; D019015:Geologic Sediments / Q000032:analysis*; D007700:Kinetics; D045483:Rivers / Q000737:chemistry*; D014872:Water Movements; D014873:Water Pollutants / Q000032:analysis*; D014876:Water Pollution / Q000706:statistics & numerical data
D014873:Water Pollutants