Study of the Anastomosing Fluvial System on the Delta Plain of the Ganjiang River

Many fluvial rivers in southern China are anabranched river pattern and most of them have been studied. But the multiple channel fluvial system on the delta plain of the Ganjiang River differs from the anabranched river pattern. The multiple channel system formed spontaneously. It was not controlled by rocky or man made nodes whereas the anabranched river was. The multiple channel system belongs to anastomosing fluvial pattern because it has the basic characteristics of anastomosing fluvial pattern in geomorphology and sedimentology such as the small channel width/depth ratio, low channel gradient, cohesive fine graind levees, interchannel wetlands and floodplains, etc. Although the Ganjiang River has low concentration of sediment, its flood plains or interchannel lands have similar sedimentary rate to that of the channels due to the import and aggradation of suspended sediment carrying by the frequent overbank flow during flood periods. The fine grain sediment of the levees that has high cohesive intensity maintains the channel stability.