flood stage
3.Abstract: This paper analyzes causal factors of flood in the middle reaches of Changjiang River.Due to neglection of environmental management,soil erosion in the upper and middle reaches of the Changjiag River,lake sedimentation,large-scale reclamation of marshes,the flood regulation capacity of the lake was descended,and flood stage was risen and prolonged.Consequently more and more river levees and lake dikes were reinforced almost every year to prevent the disasters,which made flood level go up and flood period last for more days.The frequency of flood and waterlogging disasters rose and their damage was enlarged.Several proposals for flood prevention including agricultural modernization are put forward.
5.Vertical distributions of average suspended sediment concentration of flood stage or ebb stage in the Nanhui nearshore waters of Changjiang Estuary fit to the Rouse equation: C yC a=hy-1ha-1 ωβκu *. The exponent (i.e. Rouse number) in the equation is a function of the settling velocity of suspended sediment and other parameters.
10.In light of the problem of the precision of flood forecasting being influenced by the data errors of rainfall and water stage caused by the failures of the communication and the relevant equipments of the gauging stations concerned, the techniques for the automatic hydrologic data collection and transmission system such as data extraction, examination of rationality, error identification, rainfall interpolation and the intelligent error correction are studied based on the analysis on the cause of the errors occurred in the system.
