In Korean geomorphology wetland unconsolidated alluvial deposits are categorized as coastal alluvial deposits, fluvial channel deposits, alluvial plain deposits, erosional basin-type alluvial deposits and valley fill-type alluvial deposits. The formation of alluvial deposits (alluvium) are related to the geomorphic development of base level fluctuations, coastal processes and palaeosol formations in response to climatic changes during the Quaternary. Most fluvial wetland sedimentary sequence was formed since the last interglacial.