Of great importance is the solution of the problem of research aimed at improving design methods and calculating the parameters of a bilaterally symmetrically constrained river flow with wide floodplains, for regulating river channels, protecting river banks from erosion and for the efficient use of floodplain fertile lands.The aim of this work is to develop a methodology for calculating the flow velocity field in the compression region, which is bilaterally constrained by floodplain transverse dams. Experimental studies were carried out in a schematizaron channel with a bilateral floodplain of rectangular cross section with parallel dynamic axes. It was experimentally established that the velocity distribution in the zone of interaction between channel and floodplain flows obeys the universal Schlichting-Abramovich dependence. The relative width of the interaction zone depends on the ratio of the depths of the channel and floodplain flows. The device of transverse floodplain dams to conduct to the appearance of areas of backwater, compression and spreading. In the compression region, the greatest longitudinal and transverse differences in depths are observed, as well as the velocity field with zones characteristic of jet flows: a weakly perturbed core, turbulent mixing, and reverse currents. The problem is realized for the compression domain by a joint solution of the equations of conservation of momentum and conservation of flow in the stream. Design dependencies are proposed to determine the patterns of change in speed in the channel and on floodplains. In contrast to existing solutions, the interaction of channel and floodplain flows, uneven velocity distribution in the zone of a weakly perturbed core, and transverse and longitudinal differences in depth in the compression region are taken into account. The combined use of experimental and theoretical solutions allowed the establishment of kinematic flow parameters in the compression region of the flow constrained by floodplain dams.

On floodplain rivers there are characteristic features of the construction of hydrotechnical structures, which in their design should be done taking into account this. These are the different types of floodplain and other floodplain, changes in the period of floodplain inflow, the interaction of flow and floodplain flows, the ability of floodplain rivers to water, the speed of flow and the features of turbidity, etc. The main purpose of this study is to develop a method of determining flow parameters in a two-way compressed cross-section with cross-dumbbells in the floodplain, taking into account the different bias of the Ozen and floodplain as well as the interaction of flows Experimental studies were conducted for parallel case of two-sided poise Ozen and poise flow arrows. The width of the beams is 85 sm, the width of the beams is 30 sm, the length of the lath is 11 m, the slope is i=0.0005, the slope is n=0.016 and the parameter of the dumbbells is n n =0.023. The flow parameters are long F rp =0.01-0.3, R ep >10000, floodplain F rn =0.01-0.18: R ep >4000. On the surface, the change in the compression coefficient EPR in the cases of dumbbells installation angle α d <900 and α d ≥900 was found to be heterogeneous and analytical expressions and graphs were developed to determine their values. The formulas for determining the speed of flow in a compressed cross-sectional area were proposed, taking into account the subordination of speed scanning to the expression Shlixting-Ayramovich in the zone of interaction by applying the equations of motion and consumption preservation