U.S Geological Survey, South Florida Ecosystem Program: Place-Based Studies

Project: Groundwater-Surface Water Interactions and Relation to Water Quality in the Everglades

Web Site: http://sofia.usgs.gov/projects/wtr_flux/; http://sofia.usgs.gov/sfrsf/entdisplays/waterlevels/; http://sofia.usgs.gov/exchange/harvey/harveyDATA.html; http://sofia.usgs.gov/publications/fs/169-96/

Location: Central Everglades; Palm Beach, Broward and Miami-Dade Counties

Principal Investigator: Judson Harvey, jwharvey@usgs.gov, 703.648.5876

Project Personnel: Jungyill Choi, jchoi@usgs.gov; 703.648.5472; Jim Krest, jmkrest@usgs.gov, 703.648.5472; Eric Nemeth, enemeth@usgs.gov, 703.648.5473

Other Supporting Organizations: South Florida Water Management District (Steve Krupa, skrupa@sfwmd.gov, 561.687.6923)

Associated Projects: Integrated Geochemical Studies in the http://sofia.usgs.gov/projects/wetland_seds/; http://sofia.usgs.gov/projects/evergl_merc/), Freshwater flows into northeastern Florida Bay (http://sflwww.er.usgs.gov/projects/freshwtr_flow/)

Overview & Status: The objective of this project is to quantify hydrologic exchange fluxes between groundwater and surface water and its effects on transport of contaminants in the Everglades. The principal research sites are the Everglades Nutrient Removal Project (ENR), Water Conservation Area 2A (WCA-2A), and the freshwater wetlands of Everglades National Park. Recharge and discharge between wetlands and the Surficial aquifer are being quantified, in addition to fluxes of important dissolved constituents such as nutrients, sulfate, and mercury. Furthermore, the research relates surface water and ground water interactions to past, present, and proposed management of surface-water levels and flows in the Everglades.

Needs & Products: A key measure of success in the Everglades restoration is protecting water quality under changing hydrologic conditions. Although there is a basic understanding of how interactions between groundwater and surface water will affect surface-water budgets under restoration, there is only a rudimentary understanding of how interactions between groundwater and surface water will affect water quality. Field-oriented research and modeling is determining (1) those factors that are responsible for increasing interactions between groundwater and surface water, (2) the extent to which increased interactions are flushing freshwater from the aquifer and replacing it by recharge of polluted surface water, (3) the residence time of pollutants in the aquifer, and (4) the likelihood that pollutants will be returned by discharge from the aquifer to the surface water system. Products include journal publications, USGS data reports, SFWMD cooperative agreement reports, SOFIA web site, and oral reporting at national scientific meetings and at Everglades restoration forums in Florida.

Application to Everglades Restoration: For restoration of the Everglades to succeed there must be comprehensive knowledge about physical, chemical, and biological processes throughout the system. At present there are few reliable estimates of hydrologic fluxes between groundwater and surface water in the Everglades. This gap in hydrological investigations not only leaves the water budget of the Everglades uncertain, it also hampers progress in understanding the processes that determine mobility and transformation of contaminants, such as mercury, sulfate and nutrients. The present project addresses those needs by supplying data and interpretations that are being used by SFWMD and USGS to test and verify the hydrology and water-quality models that are guiding the restoration of the Everglades.