Project Summary Sheet

Project: Geophysical Studies of the Southwest Florida Coast

Web Sites: http://sofia.usgs.gov/projects/geophys_map/

Location (Subregions & Counties): Southwest Coast/Big Cypress, Central Everglades; Miami-Dade, Monroe, and Collier Counties

Funding (Source): USGS Place-Based Studies

Principal Investigator(s): David Fitterman, fitter@usgs.gov, 303-236-1382

Project Personnel: Maryla Deszcz-Pan, maryla@usgs.gov, 303-236-1317

Supporting Organizations: Everglades National Park, Big Cypress National Preserve, and Fakahatchee Strand State Preserve

Associated / Linked Projects: Tides and Inflows in the Mangrove Ecotone (TIME) Model Development; Southern Inland and Coastal Systems (SICS) Model Development; Hydrogeology of the Surficial Aquifer System in Southwest Florida; Freshwater Flows into Northeastern Florida Bay; Ground-Water Discharge to Biscayne Bay

Overview & Status: This project focuses on the use of airborne and ground-based geophysical techniques to map the freshwater/saltwater interface (FWSWI) in the shallow coastal aquifers in Everglades National Park (ENP), Big Cypress National Preserve (BCNP), and surroundings areas. Helicopter electromagnetic surveys have been flown over large portions of ENP. In October 2001 a new survey was flown over the coastal mangrove ecotone in BCNP, a repeat of four lines in ENP to look for temporal changes, and a new survey south and east of Homestead. The BCNP portion of this survey covers an area from the Tamiami Trail north of Everglades City to the southwest near Tarpon Bay. Preliminary results of this survey are being used by hydrologists to develop the TIME hydrologic model. Further interpretation and analysis of the new data set will continue.

Needs & Products: This project provides basic information on aquifer geometry and water quality needed to develop ground-water models and test various restoration strategies. Products to date include: HEM surveys, TEM survey, and well logging in ENP; interpretation of TEM and HEM data to develop 3-D resistivity models of the area; numerous publications (project fact sheet, numerous technical papers, reports, and meeting proceedings on HEM interpretation, TEM interpretation report, HEM 3-D models, CD-ROM of HEM data), many of which are available on-line.

Application to Everglades Restoration: The data derived from this project are essential for building a regional ground-water flow model incorporating freshwater/saline water density information. When interpreted, the HEM data provide a three-dimensional estimate of ground-water quality that can not be obtained by any other means. These data improve model calibration by increasing the limited subsurface information available from wells. These data sets also provide a means of monitoring long-term changes in water quality on a regional scale due to natural and human influences.