Multi-flow-path river channel flat beach flow determination method based on river channel section terrain

The invention discloses a method for determining the flat beach flow of a multi-flow-path riverway based on the cross-section terrain of the riverway. The method comprises the following steps: firstly, establishing a flat beach characteristic value characterization system of the multi-flow-path riverway and a quantification method thereof; establishing a section terrain interpolation and standardized grid division method based on a terrain stationarity transition principle; constructing a flat beach feature value extraction model based on a water level gradual increase method, and establishing a potential flat beach feature value data set; based on an aspect ratio extreme value method and an inter-year flat beach characteristic value continuity assumption principle, establishing a grading flat beach characteristic value determination method; and based on the water level-flow relation, the multi-flow-path river channel flat beach flow determination method based on the river channel section terrain is establish