STUDY ON DYNAMIC BALANCE CHARACTERICS OF RUNOFF AND TIDAL CURRENT FOR MACRO-TIDAL ESTUARY

摘要

Based on the characteristics of Oujiang Estuary such as macro-tidal estuary, runoff varies greatly yearly and monthly, flood level rapidly rises and drops etc, Oujiang Estuary was taken as an example here to study the relationship between the ratio of the runoff and the tidal current and its dynamic balance characteristics, where a physical model of the estuary was established to simulate the current’s movement. The dominant current of the estuary which was calculated according to the various situation of the runoff and tidal current from the physical model and actual observation data, was used to analyze the dynamic balance characteristics of it in macro-tidal estuary areas. The result shows that the location of dynamic balance point in the macro-tidal estuary had a nearly connection with the ratio of the runoff and tidal current, the stagnant point goes lower reach while the ratio is large and goes up while it is little. The relationship between the topographical change and the location of the dynamic balance areas also shows that the dynamic balance areas could cause sediment accumulation. This relates to the formation of the dune inside and outside estuary. According to the calculation of dominant current, we can clearly analyze the strength of the main dynamic force in the macro-tidal estuary, and find out the regulation of the natural phenomenon.