Analysis On Division Ratio Of Bifurcated Channel And Riverbed Evolvement Of Minjiang River

Riverbed evolvement results from the interaction of water flow and the Riverbed. Damming, tideland enclosing, sand mining, bridge constructing and river channel improvement, all these activities on the river cause the riverbed evolving more quickly and severely. Research of division ratio and riverbed evolvement is important to natural disaster reduction and alleviation, water resources utilizing properly. It is helpful to bring about the society and economic sustained and coordinated development.As bifurcated channel of Minjiang River to be object of study, the pattern of division ratio variation and riverbed evolvement on its south and north lower streams have been researched in the paper.With human activity in lower stream of Minjiang River more actively, the balances of water and sand, and the erosion and deposition on the bifurcated channel have been upset severely in recent year. The situation of the riverbed is changes from low-flow scour and flood deposit in history into north lower stream scour yearly, which cause the division ratio of the north lower stream and the drought period of the south lower stream increasing yearly. Hence, it is necessary to research the division ratio and the riverbed evolvement on the bifurcated channel to bring the lower stream riverbed of Minjiang River under control.The yearly records of water level, rate of flow and section of the riverbed of bifurcated channel on lower stream of Minjiang River, and the material of division ratio and river's riverbed evolvement and hydro-structure arrangement history have been investigated in the paper. According to these materials, the paper analyzes the relationship of division ratio versus above factors. The relationships of the division ratio and the riverbed evolvement, and the division ratio to water flow, sand flow, water-flow section area and riverbed evolvement finally are revealed by the paper, which provided scientific basis for Minjiang River control, and a valuable reference to similar river control and water resources utilizing properly.