projects > groundwater discharge to biscayne bay > project summary
Project Summary Sheet
U.S. Geological Survey, Greater Everglades Science Program: Place-Based Studies
Fiscal Year 2002 Project Summary Sheet
Location (Subregions & Counties): Southeast Coast; Miami-Dade County
Funding (Source): USGS Place-Based Studies / Army Corps of Engineers
Principal Investigator(s): Dr. Christian Langevin, firstname.lastname@example.org, 305.717.5817
Supporting Organizations: Miami-Dade Department of Environmental Resource Management, Army Corps of Engineers
Associated / Linked Projects: Hydrodynamic Model of Biscayne Bay, Rob McAdory, Army Corps of Engineers/Waterways Experiment Station
Overview & Status: The purpose of this project was to quantify the rates of ground water discharge to Biscayne Bay. Project objectives were achieved through the collection of field data and the development of two- and three-dimensional, numerical models that simulate variable-density ground water flow. As part of this project, the SEAWAT code, which represents variable-density ground water flow, was developed to simulate ground water discharge. Monitoring wells were installed offshore and inland along three transects perpendicular to the shore of Biscayne Bay. Water samples collected from the offshore monitoring wells indicate that brackish ground water extends offshore beneath Biscayne Bay. Numerical models calibrated to the field data, also suggest that brackish ground water is discharging to Biscayne Bay. Average freshwater discharge rates simulated by the model are about 10 percent of the freshwater discharge from canals. The final report was approved at the end of FY2000 and was distributed in FY2001. An article on ground water discharge was submitted to the journal, Ground Water. Beta versions of the SEAWAT code were also distributed at the end of FY2000; the SEAWAT code was documented and published under the project, Ground-Water Flow and Transport in the TIME Model Domain (Langevin PBS project).
Needs & Products: The U.S. Army Corps of Engineers (USACE) is currently developing a numerical hydrodynamic model of Biscayne Bay. One of the required inputs to the hydrodynamic model is the quantity of ground water that discharges to Biscayne Bay. Estimation of ground water discharge to Biscayne Bay is difficult because of the complex ground water flow patterns that exist near the coastal boundary. The complex ground water flow patterns are caused by tidal fluctuations and density variations that cause a saltwater tongue to form at the base of the Biscayne aquifer. Estimates of ground water discharge, obtained as part of this study, have been provided to the USACE and are currently being used in their hydrodynamic model
Application to Everglades Restoration: This report is one of the first documented efforts of a numerical model that simulates ground water discharge to a coastal marine estuary. The Army Corps of Engineers is using the discharge estimates from this project in their hydrodynamic circulation model, which is currently being used to evaluate the effects of restoration alternatives on Biscayne Bay. In addition, the SEAWAT code, which was developed as part of this study, has been widely accepted by the south Florida modeling community and will be used for other CERP projects, such as aquifer storage and recovery.