Predicting flood flows in rivers that flow through populated areas is of great importance, and computer models are useful tools in such an endeavor. This paper outlines a comparison study that examined the water surface and bed elevations of the 100-year flood event in the Rillito River at Tucson, Arizona. The results from IALLUVIAL2 were compared with those from HEC-RAS and GSTARS, as well as stage data from the USGS. Results showed that IALLUVIAL2, which cannot compute bridge effects, predicted a flood similar to that of the more commonly used HEC-RAS model, which does take into account bridges. Both models underestimated the flooding by about 2 to 4 feet, but accurately predicted the recession of each flood flow. This study also compared different equations within the IALLUVIAL2 model to find the most appropriate sediment transport and roughness equations for this particular river and found that Laursen and Manning's gave the best results. The results indicated the need of an appropriate model for predicting flood flows in ephemeral streams for water resource managers, engineers and urban planners.
AGU Fall Meeting Abstracts
- Pub Date:
- December 2007
- 1821 Floods;
- 1894 Instruments and techniques: modeling