Effects of river dominated level and water level fluctuations on distribution distance of a lake, river dominated delta

Key words:  river dominated delta  distribution distance  river dominated level  water level fluctuation

Abstract:

Taking the Poyang Lake Ganjiang Delta and Gubei Depression as main study objects, this study focuses on the distribution distance of a lake river dominated delta affected by river and water level fluctuations.Using statistical analysis of typical river dominated deltas satellite photos and fine anatomic of underground work area delta, this paper first used two parameters to express river dominated level, then illustrated the relationship between delta distribution distance and altitude, sediment depth and length, and slope angel of delta front lobe.Lastly, the effects of river dominated level and water level fluctuations on the distribution distance of delta are clarified. The results show that there are two parameters to express river dominated level:the slope in relationship type of delta split level and cumulative quantity of distributary channel, and the delta 's opening angel. The smaller the slope and opening angel, the larger the river dominated level and the delta 's distribution distance. With the extension of the delta, its altitude decreases logarithmically decrease up to the prodelta 's height. The slope angle of delta front first increases and then decreases subsequently. With the increase of sediment depth, the length of every delta lobe linearly increases, and the slope angle increases logarithmically until the suspension angle. Water level fluctuation ΔH and delta distribution change ΔL are mainly controlled by basins slope α and delta front slope β and ΔL=1〖〗tan α-1〖〗tan βΔH.