Approach to isobath-change-model of tidal coast

In recenty ears,along with the reduction of the silt and sand transported by the rivers to the sea, the erosion to the bank of the China's coastturns to be worse and worse.So it is important and urgent and of realistic significance to study the rule of shoal evolution and thus to establish a reasonable and feasible forecasting model.A for ecasting model suitable to the evolution of tide-type coast beach is established by applying Professor U da's theory of equal-depth-line forecasting model.A key point in establishing the model is to find a reasonable solution in calculating the quantity of near-bank silt and sand along the equal-depth-line.The concept of the distribution of wave-breaking time in intertidal zones is introdued and thus the quantity of sand transpo rtation in the intertidal zones in the half-tide period is put forward as well as its distribution along the profile of shoal.Aforecasting calculation of the bank in South Shandong Province is made by using the model and its result is verified.It shows that the result is reasonable and basically reflects the characteristics of the evolution of that section of shoal.