EWRI Presentation 2019
Paul M. Craig and Thomas Mathis will present a paper at the ASCE/EWRI Congress 2019 on “Estuarine Salinity Intrusion and Implications for Aquatic Habitat: A Case Study of the Lower St. Johns River Estuary, Florida”. The paper will be presented on Wednesday, May 22 10:30 AM – 10:48 AM Room: King’s Garden 3, Wyndham Grand Pittsburgh Downtown, PA.
“The Lower St. Johns River estuary in Florida has experienced both urban and exurban development along its banks over the course of many decades. The extent of salinity intrusion into the freshwater portion of the estuary is controlled by a combination of factors which may be altered through natural or anthropogenic forces.
To better understand the factors controlling salinity intrusion, the Environmental Fluid Dynamics Code Plus (EFDC+) was applied to model the hydrodynamics of the estuary over 120 river miles, from the Atlantic Ocean to the freshwater lakes at the head of the estuary. To accurately model interactions between the river and shallow off-channel areas (i.e. marshes and wetlands), the Sigma-Zed (SGZ) vertical layering scheme was utilized for this study. The SGZ scheme allows the number of layers to vary horizontally which dramatically increases the computational efficiency of the model.
This study discusses the calibration and validation of the model, and application of habitat analysis to the model results using the EFDC_Explorer Modeling System (EEMS). The calibration process involved adjusting model parameters to simulate dynamic changes in water level, salinity, and discharge at various locations in the estuary. The analysis of habitat examined the role of salinity concentration in determining the distribution of habitat for aquatic plants and animals in the transitional area between fresh- and saltwater dominated parts of the system. The results of this study demonstrate the importance of detailed hydrodynamic models in understanding both the dynamics of the system and the subsequent implications for aquatic habitats.”