Deltas and estuaries worldwide face the challenge of capturing
sufficient sediment to keep up with relative sea level rise. Knowledge
about sediment pathways and fluxes are crucial to combat adverse effects
on channel morphology, e.g. erosion which enhances risk of bank collapse
and increasing tidal penetration. We constructed sediment budgets which
quantify annual changes for the urbanized delta of the Netherlands
affected by fluvial and coastal fluxes of sediment, engineering works
and dredging and dumping activities. The Rhine-Meuse delta shows a
negative sediment budget in recent decades due to anthropogenic
intervention. Following a large offshore port expansion, dredging in
ports and harbours in the region has doubled in the past five years,
likely due to the induced change in net sediment fluxes. In addition,
the deeper navigation channels, ports and harbours are trapping siltier
sediment than before, changing sediment composition in the mouth. The
removal of sediment from the system through dredging is adverse to the
necessity for sediment in heavily eroding branches. To allow for
sustainable sediment management in the future and to cope with sea level
rise, further measurements are required to properly quantify the amount
of incoming sediment from the rivers and the seaward boundary and the
mechanisms of transport which are key to solving the sediment issues in
the delta. The varied response of the branches has important
consequences for navigation, ecology and flood safety and management of
the sediment in the system will be of pivotal importance in coming
decades and for other deltas worldwide.