Rating Curves for Dam-Break Flows

Abstract

The area of a looped rating curve for a channel cross section is indicative of the dynamic effects of a flood wave. These effects may be used as a criterion to decide the suitability of a simplifying approximation, such as dynamic, kinematic or diffusive wave modeling, for the analysis of dam-break flow. Two approximate models to calculate the area of the nondimensional loop for dam-break flow are developed herein based on the computed results for several hypothetical dam failure cases. A comparison of the results obtained from the approximate models and those by simulations shows that approximate models can be used to predict the nondimensional loop area for short distances from the dam. As expected, the area of the nondimensional loop decreases as the flood wave moves downstream, it increases as the breach width increases and it decreases for increased breach time and/or flood-plain width.