Method for calculating resistance coefficient of watercourse containing submerged flexible vegetation

The invention relates to a calculation method for a resistance coefficient of a watercourse containing submerged flexible vegetation. The calculation method comprises the following steps: determining an analytical formula of a Darcy-Weisbach coefficient f of the watercourse submerged with the flexible vegetation; analyzing an f analysis formula, finding out vegetation factors influencing f in the formula, and establishing a dimensionless relationship between the vegetation factors; relevant data of the river channel and the vegetation are obtained through collection, the data are divided into a training group and a verification group, and a genetic algorithm is adopted to obtain the relation between f and each dimensionless factor; and comparing the measured value and the calculated value of the f by adopting a correlation coefficient and a root-mean-square error so as to evaluate the fitting degree between the f and each dimensionless factor. On the basis of integrating the water depth, the vegetation distri