Inter-Model Comparisons Between Physical and Numerical Models

This report was developed by The Water Institute (the Institute) for the Coastal Protection and Restoration Authority (CPRA) under Task Order 69 Lowermost Mississippi River Management Program (LMRMP).

CPRA has been using various tools to support coastal restoration projects. Among these tools, the Lower Mississippi River Physical Model (LMRPM) and the numerical Basin Wide model Version 4 have been used as part of the LMRMP to identify and test management strategies for the river. The report summarizes the comparison between these two models. Simulations with similar inputs and environmental conditions have been performed with both models, allowing for inter-model comparison. The comparison focused on simulations related to a future without any projects (sediment diversions) implemented on the landscape and included the same forecast window from 2020 to 2070. The simulations included the same sea level rise, Mississippi River hydrographs, and similar upstream sediment input. The analysis included the comparison of river discharge, stage, bed elevation, and dredging volumes between the two models, and where available, model results were also compared to observations within the river.

Geologists, geomorphologists, and engineers from the Institute, Louisiana State University, and CPRA contributed to this work and to the development of this report.