The U.S. Army Corps of Engineers (USACE) has access to two hydrodynamic numerical software, the Adaptive Hydraulics (AdH) suite and the HEC-River Analysis System (HEC-RAS). This report presents the results of an investigation into the performance of pre-existing AdH and HEC-RAS-Diffusive Wave (DW) models in capturing inundation, maximum water surface elevations and numerical efficiency when applied to the Morganza Floodway/Atchafalaya Basin. This report accomplishes this using the Mississippi River flood of 2011 as the comparative flood event. During the event the Morganza floodway was operated and an extensive dataset of the rise and fall of the flood hydrograph at several locations exists. The results from AdH and HEC-RAS-DW were compared to observations, and conclusions drawn. The authors emphasize that the AdH and the HEC-RAS-DW models were developed for different projects. The AdH model was developed to investigate the inundation in the Morganza floodway and was therefore previously validated to observations within the floodway, and the HEC-RAS model was developed to capture flow in the Atchafalaya Basin and was therefore previously validated to observations within the vicinity of the Atchafalaya river. This presentation will present the results of this comparative analysis.

US Army Corps of Engineers Adaptive Hydraulics and HEC-RAS: A Quantitative Analysis

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