Hydraulic resistances of eroded riverbed and assessment of their sustainability

Abstract

In the world, due to the shortage of water resources, the most important issues are the rational use of water resources, the assessment, and the improvement of the capacity of riverbeds and channels. In this regard, research developments on improving the methods of the hydraulic calculation of the resistance and the stability of mobile river channels and channels are of particular importance. The results of some theoretical and experimental studies of hydraulic resistances and the stability of watercourses by scientists in the CIS and abroad are considered. The analysis of massive field data on the Darcy coefficient (Shezi) of earth channels covered in a sandy mobile bed is performed. With a change in the flow velocity field, the roughness of the channel surface changes, changing its size and shape, which determines the channel's resistance to flow movement. It is established that in stable channels with certain widths, the flow velocity is evenly distributed, having one maximum along the channel axis, and the movement is carried out in the form of a compact single jet along the flow cross-section. With changes in hydraulic conditions, the curvature of the isotopes is observed, the flow tends to split, and several closed systems of rotating the jet appear, which are signs of the development of channel deformations.