DESIGN OF SLIT DAMS FOR CONTROLLING STONY DEBRIS FLOWS

1 INTRODUCTION Stony debris flows are natural, highly concentrated water-sediment mixture, which forms wherever the simultaneous availability of water, debris material and an adequate slope, steeper than o10 are satisfied (Gregoretti, 2000). In mountainous regions of Taiwan, due to vast development and utilization of hills, stony debris flows are important from the point of disaster prevention, since they occur frequently and often bring about heavy loss of lives and properties. Therefo…

DESIGN OF SLIT DAMS FOR CONTROLLING STONY DEBRIS FLOWS

A new method to a slit dam for controlling the stony debris flow has been derived based on the mass conservation law of the stony debris flow passing through a slit dam and the laboratory experiment results. This new method is then combined with three primary efficiency expressions: the dimensionless sediment outflow ratio, the sediment concentration ratio, and the sediment storage rate to develop a simple module, with which the height and the spacing of the posts, as well as the total spacing of slit dam are determined. Furthermore, these expressions can also be applied to check those slit dams that have already been constructed with their effectiveness against various magnitudes of the debris flow. The comparison between these expressions and laboratory data is in reasonable agreement.