Abstract:Flood waves resulting from flash floods have been responsible for numerous damage and losses of life. In the present study, an experiment was conducted to investigate surging waters down a stepped channel, which is 2.4m long, 0.5m wide and with a slope of 0.133, both in the circumstances of being roughed and non-roughed. Wave front propagation data from the non-roughed series compared with Chanson’s [2004] showed, that for some smaller flow rate, since the relative step height h*, defined as the ratio of step height to the characteristic length of flow rate raised, the dimensionless wave front celerity would no longer remain constant as C*=1.5 given by Chanson, but reduce as the flow rate lessened. Another analysis of the data from the roughed series showed, that the large roughness has a significant negative effect on the flash flood propagation, as well as on the energy carried by the rushing water. And this may provide some advice on the flash flood defense during the reconstruction in the earthquake-hit area.
