2D Modeling of Freshwater Diversion from the Mississippi River into Bayou Lafourche
Donaldsonville, Louisiana
FTN performed all hydrodynamic modeling for the proposed freshwater diversion of Mississippi River water into Bayou Lafourche near Donaldsonville, LA for the DNR and US EPA.FTN used the Corps of Engineer's two-dimensional models RMA-2 and RMA-11 models to represent the Barataria and Terrebonne Basins with their complex system of interconnecting waterways, marshes, and swamps. Tasks included:
- Selection of hydraulic models to represent the system;
- Model geometry setup, calibration and verification, and application to proposed design scenarios.
Because of the excellent documentation of previous work by FTN, FTN was able to use existing survey data corrected to the LA Coastal Zone Primary GPS network for over 90% of the study area, resulting in a substantial savings to the State of Louisiana. FTN worked with Dr. Ian King, the model's author, to modify the model source code to make it more applicable to the Terrebonne and Barataria Basins including adding representation of irregular-shaped channels for more accurate prediction of the impacts of the project on drainage and flooding in developed areas and a more computationally stable channel-marsh overflow exchange routine. FTN assisted in the computation of wetland benefits by computing the area of reduction in salinity for different salinity ranges.
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