Duplantis Design Group

Hydrodynamic modeling for the Fritchie Marsh

One year

The Challenge

This project was intended to gain insight into the hydrodynamics of Fritchie Marsh, a wetland system on the North Shore of Lake Pontchartrain region where several marsh creation restoration projects are currently under design and construction. The data and tools developed for this project were used in conjunction with existing drainage models of the Slidell area to identify future hydrologic restoration projects within Fritchie Marsh that would ultimately have a dual benefit of improved salinity dynamics within the marsh and increased drainage capacity upstream. 

The Approach

Specifically, the Institute was tasked with data collection, evaluation, and processing. This included gathering, cataloging, and evaluating existing datasets to support the hydrodynamic modeling for the site of interest. This also included developing a data gap report based on available and anticipated datasets, processing data from each of data collection stations, formatting available topographic and bathymetric data, and post-processing data from each of the short-term time-series data collection stations established for this project. 

The next phase for the project was to conduct hydrodynamic modeling to simulate the flow and salinity dynamics in the vicinity of the site to gain a comprehensive understanding of the water level and salinity regimes under various conditions. A two-dimensional model was calibrated to the data collected by the Institute field data and was used to examine various operational plans and hydrologic changes (e.g. improving the conveyance capacity of drainage bayous) to enhance the drainage of the area. Ten project alternatives, designated by the project team, were simulated for both future with and without project conditions. Last, the Institute team assessed and interpreted the modeling outcomes and worked with the project team to understand consideration of the different restoration options.