External forcing and emergence in fluvial systems: results from a fluvial system model compared with observations from the Holocene Rhine-Meuse delta

Abstract

We use the Rhine-Meuse fluvial deposits to evaluate our findings from the modelling study. Using paleogeographic maps representing the delta evolution over the Holocene, we calculated time series of bifurcation frequency, avulsion frequency, and the number of co-existing active channel belts on the floodplain (Stouthamer and Berendsen, 2001; Stouthamer and Berendsen, 2007). These time series show a similar periodicity in fluvial system dynamics simulated by our model thus confirming our modelling results. However, observed avulsion sequences consisting of avulsion locations that gradually shift in upstream direction on the floodplain are not found in our model. This may be due to limitations in the process representation. The results of this modelling study are relevant for interpretation of fluvial sequences. Under the assumption of a correct representation of processes in the model, it is shown that emergence does occur in fluvial systems (at this scale) and thus needs to be taken into account when estimating reservoir properties.