Estimating and modeling the annual contribution of authigenic sediment to the total suspended sediment load in the Kleine Nete Basin, Belgium

In the Nete basin (Flanders, Belgium) chemical precipitates derived from groundwater-associated Fe2+ seeping into the overlying surface water significantly contribute to the composition, concentration, and fluxes of suspended sediment.The degree of contribution of these precipitates for the period of 1999 up to 2004 was determined by comparing measured annual suspended sediment loads with theoretical calculations as well as values generated with MARS (Model for Authigenic River Sediment) (1.0), a numerical model newly developed for predicting authigenic sediment flux. Theoretical calculations, based on various estimates of the concentration of Fe2+ in groundwater, after stoichiometric and sorption correction, place the averaged annual contribution of authigenic sediment between 43% and 100% for the period-of-record. MARS 1.0 predicts annual contributions of authigenic suspended sediment of 58% up to 96%.