Spatial and temporal variability of sediment fluxes from a coastal Mediterranean river: the Tet (France)

The purpose of this study is to investigate the fluxes of total suspended s olids (TSS) in the T (e) over capt River system (1380 km(2)). On the basis of a great number of measurements, we estimate the mean annual sediment flu x at the mouth to be about 53546 t(.)yr(-1) (nearly 40 t(.)km(-2.)yr(-1)) f or the period 1980-1999 (average annual water discharge 10.4 m(3.)s(-1)). A lmost all suspended sediment loads are transported during brief flash flood s that mainly occur during autumnal heavy downpours. The scarceness of thes e events leads to a very large inter-annual variability of the river sedime nt fluxes (from 1 to more than 100). Despite the damming of the river in th e central part of its drainage basin, the observed sediment fluxes are more important downstream the dam than upstream. This can be explained by low s ediment retention behind the dam, by greater erosion rates in the downstrea m part of the basin, filled with crumbly Plio-Quaternary formations. and by heavy storms located in the fore land. (C) 2001 Academie des sciences / Ed itions scientifiques et medicales Elsevier SAS.