Large estuary systems like the Elbe Estuary usually consist of one main estuary and many tributaries. These tributaries play an important role since they act as transitional waters between marine and fluvial environment. One of the main functions of the tributaries is the drainage of the low-lying marshes in the river catchment. The drainage capability of the tributary depends amongst others on the hydraulically effective cross section, which is influenced by morphological processes. The morphological development mainly depends on the sediment supply from the catchment as well as from the main estuary. In particular, the latter is highly variable due to the non-stationary estuarine turbidity maximum (ETM) in the main estuary (Kappenberg & Fanger 2007). Hence the morphological development of the tributaries – which is for the most parts unknown – can be assumed to be highly variable as well.
