Land Reclamation Controls on an Estuarine Regime Shift from a Multichannel to Single Channel Configuration

Abstract

Deltaic intertidal areas disappear worldwide. This impacts delta morphology, because the extent and physiological character of the tidal floodplains control the tidal regime and, as a result, residual sediment transport patterns. Extensive reclamation of former tidal flats, effectively changing the ratio of channel volume to intertidal storage volume (Vs/Vc), drastically changes the functioning of the estuarine system. This might result in morphodynamic feedback loops that reach a tipping point towards an alternative stable regime (Van Maren et al., 2023). Our capacity to predict the consequences of future land reclamation or depoldering methods, a measure frequently suggested to cope with the effects of sea level rise, is limited, because the conceptual framework describing estuarine response to tidal flat reclamation fails to predict such regime transitions.