Services Rendered:

EFDC Hydrodynamic Modeling

Salinity Modeling

Sensitivity Analysis

Habitat Analysis

Client:

USACE Jacksonville District

Contact:

Mr. Steven Bratos

Senior Coastal Engineer,

USACE, Jacksonville. [email protected]

Dates of Performance:

2017-2019

Status of Project:

Completed

DSI has supported two phases in the evaluation of the Jacksonville Harbor Navigation Project for USACE. The study uses EFDC+ with Sigma-Zed for hydrodynamic and salinity modeling to evaluate changes to the salinity in the Lower St Johns River (LSJR).  The Jacksonville Harbor feasibility study (USACE, 2014) demonstrated that the partially-stratified LSJR estuary required a three-dimensional hydrodynamic model to accurately simulate salinity variations with depth. The purpose of this study was to evaluate potential impacts of salinity intrusion into the estuary on the aquatic habitat and create a basis for evaluating multiple management scenarios to support decision-making.  To model the LSJR estuary, the EFDC+ hydrodynamic and salinity model was utilized. Five separate simulation periods were used for model calibration and validation.  Data collected by USACE, NOAA, USGS, and the St Johns River (SJR) Water Management District were used to calibrate the EFDC+ model for water surface elevation and salinity.  Following model calibration, an 8.5-year Production Run (PRP) from January 2008 to June 2016 was run in order to evaluate the long-term trends in salinity intrusion and analyze the long-term behavior of the estuary in relation to salinity stress on locations in the estuary with submerged aquatic vegetation beds (SAV), and wetlands. A habitat analysis concerning submerged aquatic vegetation and wetlands was performed which serves as a baseline for comparison with alternative management and future change scenarios for the basin.