Modeling Water Quality in Breton Sound Estuary, LA

Kelin Hu, Louisiana State University, Baton Rouge, LA, 70803: khu@lsu.edu;
Q. Jim Chen, Louisiana State University, Baton Rouge, LA, 70803: qchen@lsu.edu; and Hongqing Wang, USGS Wetland and Aquatic Research Center, Baton Rouge, LA, 70803: wangh@usgs.gov

How will freshwater diversion projects and sea level rise affect ecosystem structure and functions in Louisiana? The ability to accurately assess and predict these influences is important as coastal restoration efforts need to better understand the hydrodynamics, sediment transport and water quality (e.g. salinity, temperature, suspended sediment concentration and chlorophyll-α concentration) in Louisiana estuaries.

The Delft3D model suite, including the hydrodynamic and water quality modules (i.e., Delft3D-FLOW and Delft3D-WAQ), was applied to the Breton Sound estuary for simulations of water quality. Parameters in water quality were carefully chosen, calibrated and validated via field observations at multiple stations across the Breton Sound estuary. Distributions of salinity, temperature, suspended sediment and chlorophyll-α concentration in the estuary were examined. Model results were in good agreement with field measurements. In addition, a series of numerical experiments were carried out to investigate the effects of freshwater diversion project and sea level rise on these water quality variables in Breton Sound.