THE STABLE LONGITUDINAL PROFILES OF RIVER BEDS

All present river bed equilibrium theories presuppose rectangular sections. This practice will bring satisfactory results in the case where the cross section of the river bed is nearly horizontal like that of the upper reaches of a sand-bank dam, but is not accurate in the case of a complicated cross section or of the cross section of a compound channel often seen at a repaired river. In this paper, therefore, the analysis is made of equilibrium longitudinal sections of river channel with consideration for the cross sections. As the cross sections in the dynamic equilibrium state still remain unknown, examples of the cross sections of compound channels and parabola have been taken for cross sections. Two kinds of solutions under varied equilibrium conditions have been worked out by using the Manning's roughness coefficient n and the equivalent roughness ks for the friction term. Also studies have been made on theoretically unsolved factors and application problems. By the method of this paper it will become possible to obtain solutions for general stable cross sections too in similar ways.