The analysis of N.N. Pavlovsky's method for calculating the parameters of the riverbed in the branches is given. The reasons for the limitation of this method have been established. The Lagrange transform is used to find the extremum of the objective function for equations of uneven fluid motion, which makes obtaining an equivalent resistance modulus highly visual and easy to use. The results of the experiment are presented.

Keywords: calculation method, multi-node sections of rivers, resistance modulus, N.N.Pavlovsky method

The method of numerical calculation of the parameters of the river channel in the arms is given. The method of nonlinear programming for analysis of dissipative systems with concentrated parameters is used. The technique is focused on computer modeling in the environment of engineering package MathCad. The results of the experiment are given.

Keywords: Distribution of water flow, calculation method, multi-node sections of rivers, water flow

The current problems of calculating the distribution of water flow along the branches, in multi-arm river sections are considered, the problems of current calculation methods are identified, a new calculation method is proposed, the proposed method is analyzed for efficiency, a calculation optimization method is proposed, a regularization parameter is proposed, an analysis of the changed formulas is carried out, analysis of the changed formulas is carried out, analysis is carried out calculation errors.

Keywords: waterways, water expenditures, modeling

The article discusses the current problems of calculating the distribution of water flow; the problems of current methods based on solving nonlinear equation systems are identified; proposes a new method for solving problems; analysis of the effectiveness of the proposed method; proposed a way to optimize the simulation calculations.

Keywords: waterways, water expenditures, modeling