Method of computing overall tailwater channel filling at low-head hydraulic centers of the AMU-Dar'ya river

摘要

1.With a markedly reduced discharge of the tailwater at the hydraulic centers, as a consequence of higher diversion and the arrival of coarser fractions from the settling basins, the portion of the load too heavy to be transported is deposited, chocking the channel and raising its bottom and water level. The most important point in determining the overall obstruction of the tailwater channel is the carrying capacity of the stream. Its determination is quite difficult because the plainland rivers with channels in fine-grained sand, transporting a heavy load, are subject to continuous deformations and changes. Under such conditions, it is recommended to draw curves v=f(Q) and Hav=f(Q) for the newly formed channel whose parameters are determined, for conditions similar to those of the Amu-Dar'ya, from Eqs. (8)–(10).2.Correlation of curves v=f(Q) and ρc=f(Q) for fractions d>0.05 mm, and the actual data for the Kizyl-Ayak hydraulic center, shows a fair agreement between the theoretical and observed data; the inference is that the theoretical points define the saturation load of the stream; the length of the tailwater over which aggradation takes place, as well as the bottom and water rise, can be determined with Eqs. (19)–