The role of marsh creeks in the development of salt marshes during storm events

Salt marshes are valuable ecosystems in coastal wetlands as they provide many functions. However, salt marshes are increasingly threatened by the sea-level rise induced by climate change. Whether there is enough sediment availability is the key to the survival of salt marshes. Storm events can provide a large amount of sediment from mud flats to salt marshes and are the main driver of marsh accretion in the long term. Sediment can be transported into the marsh via both marsh edges and marsh creeks. How important the role of marsh creeks is in delivering sediment into marshes during calm weather and storm events needs to be further investigated. Therefore, one field campaign in Paulina Saltmarsh (the Netherlands) has been conducted in the summer. As storm events frequently occur in winter in the Netherlands, the other field campaign in Paulina Saltmarsh is ongoing in January. Water depth, velocity, SSC, and bed level change have been measured simultaneously at three locations: the mud flat, the marsh creek, and the marsh edge. According to the results from the summer field campaign, we found that the marsh creek generally functions as a conduit for exporting sediment during calm weather. Sediment import can only be observed when the mud flat was eroded and provided more sediment to the creek. Due to the lack of sediment availability, mud flats cannot be recovered easily after erosion. During storm events, marsh creeks are expected to reverse the role in delivering sediment. In addition, the contribution of creeks and marsh edges to the transport of sediment will be explored. This work reveals different sediment transport regimes under different conditions, and highlights the role of creeks in the expansion of marshes during storm events.