Limitations of de Saint Venant Equations in Dam‐Break Analysis

Results of solitary waves and laboratory‐scale dam‐breach flood waves propagating in one‐dimensional channels are compared as described by finite difference analog equations to the de Saint Venant and Bôssinesq equation systems. Additional terms accounting for streamline curvature effects on the vertical pressure distribution extend the long‐wave de Saint Venant system to a quasi‐longwave, Boussinesq system. Where the input hydrograph wave period is greater than about 100 seconds, the de Saint Venant equations are sufficient. These results cover most flood waves resulting from dam breaks of practical interest. Further research is needed to completely define the limitations of the de Saint Venant system in terms of both the Ursell parameter and the wave period for other shortwave phenomena in canals and rivers.