不規則断面水路の洪水流(1)

Abstract

This paper treats the unsteady flows in irregular open channels considering the effectsof the existence of storage region abutting on the main channel region and of the largescale horizontal mixing.The fundamental equation of unsteady flow under this kind of channel condition hasbeen derived through theoretical considerations upon a one-dimensional system of equationsof continuity and momentum. The newly derived equation is a modification of the termsfor transportation and diffusion in the diffusional equation derived by S. Hayami.A comparison between routed flows using actual and averaged cross sections indicatesthat the solution obtained using widths averaged along the complete river reach is a goodapproximation for the irregular channel flood.An example of application of this theory for the flood which was brought by thetyphoon 5915 (Vera) in the Kizu River has shown a good agreement with the observedhydrograph.