projects > groundwater-surface water interactions and relation to water quality in the everglades > work plan
Project Work Plan
Greater Everglades Science Program: Place-Based Studies
Project Work Plan FY 2003
A. GENERAL INFORMATION:
Project Title: Groundwater-Surface Water Interactions and Relation to Water Quality in the Everglades
Other Investigator(s) and Staff: James M. Krest (NRC-post doc), Jessica L. Thomas (M.S., contract), Eric Lerch (student), Christopher Roland (summer student)
Successful restoration of the Everglades requires comprehensive knowledge of ground-water recharge and discharge, but few reliable estimates are currently available. These gaps not only leave the water budgets uncertain in some areas, but also hamper progress towards understanding the mobility and fate of waterborne contaminants. A critical concern for the restoration is the response of water quality to the planned modifications of the hydrology. What will be the effect of doubling the flow in the Everglades using water that potentially is of poor quality? Almost certainly contaminant levels of sulfate, mercury, and phosphorus will move farther into the system than ever before observed, but the rate of movement of contaminants is uncertain because there are essentially no investigations of the fundamental processes of solute transport in the Everglades.
Our project addresses these needs by quantifying solute fate and transport in the Everglades, including fluxes between surface water, peat pore water, and the underlying aquifer. The goal is to determine the combined effects of solute transport in surface water and surface-subsurface exchange of water and solutes. The target is better understanding of processes controlling the movement and fate of mercury, phosphorus and sulfur in the Everglades. Also to be determined is the relative importance of the controlling factors (including water-resources management) in driving surface-subsurface exchange and enhancing transformation of solutes. Because contaminants stored in subsurface zones will be released only slowly back to surface water, greater knowledge of the storage of contaminants in subsurface zones is needed to predict future effects on water quality in the Everglades. Our data and interpretations are (or soon will) be used to parameterize some of the more important hydrology and water-quality models guiding the restoration, including TIME (USGS-Langevin, Swain, and Schaffranek), ENR Nutrient Balance (SFWMD-Chimney), and STA Design Reassessment (SFWMD-Kadlec/Walker and DB Associates), SFWMM (SFWMD-Obeysekera), ELM (Carl Fitz, SFWMD), and modeling by the FIU/SERC phosphorus dosing flume study (Evelyn Gaiser, FIU, P.I.).
FY02 Selected Accomplishments:
Our partnership with SFWMD produced the most reliable and widely used estimates of recharge and discharge in the Everglades Nutrient Removal (ENR) project, serving the SFWMD as the basis for their calculations of nutrient removal efficiency, and providing critical understanding of the likely role of groundwater in performance of the newly-completed Stormwater Treatment Areas. In 2002 we finished a major interpretive report on that project to supplement a previous journal article and a comprehensive data report (see attached letter). This year we also provided key data sets and preliminary analyses of recharge and discharge to USGS colleagues that are helping to guide more detailed modeling of groundwater-surface water interactions in Taylor Slough
FY02 Selected Products:
Harvey, J.W., Krupa, S.L., Gefvert, C., Mooney, R.M., Choi, J., King, S.A., and Giddings, J.B., 2002. Interactions between surface water and ground water and effects on mercury transport in the north-central Everglades. U.S. Geological Survey Water Resources Investigations Report 02-4050, 82 p.
Krest, J.M. and Harvey, J.W., 2003, Using natural distributions of short-lived radium isotopes to quantify groundwater discharge and recharge. Limnology and Oceanography, 48(1):290-298.
Bates, A.L., Orem, W.H., Harvey, J.W., and Spiker, E.C., 2001, Tracing sources of sulfate in the Florida Everglades. Journal of Environmental Quality, 31(1):287-299.
Bates, A.L., Orem, W.H., Harvey, J.W., and Spiker, E.C., Geochemistry of Sulfur in the Florida Everglades: 1994 through 1999. U.S. Geological Survey Open File Report 01-7. 54 pages.
FY03 Objectives and General Strategy:
Our objective for FY03 is twofold, 1) to conduct a fundamental solute tracer experiment in the FIU/SERC flumes that will produce some of the first parameters describing solute transport in the Everglades (needed for water quality models), and 2) to expand the spatial scale of our measurements, using an extension of the radium tracer approach, to allow parameterization of solute transport at spatial scales of tens of kilometers. The advantage of our plan is that it is based in detailed experimentation at the FIU/SERC flume sites, but is also combined with a larger scale approach using natural distributions of radium isotopes to quantify solute tracer parameters at larger scales. Our hope is that we can confirm (using the results from flume experiments) the radium-tracer approach as a means to quantify solute tracer parameters at larger spatial scales. What we will gain by this dual approach to parameterizing water-quality models is both a "process-scale" and "watershed-scale" assessments of interactions between surface water and subsurface water and how they affect transport of solutes and contaminants through Everglades wetlands.
Potential Impacts and Major Products for FY03/FY04:
An increasing group of researchers have identified water-quality issues as key issues that will affect success of the Everglades restoration. The foundation of the restoration is the doubling the flow through the Everglades to restore pre-drainage hydropatterns. In our opinion not enough scientific attention has been given to how increased flow will affect the movement of solute contaminants that are introduced at the northern end of the system. Many scientists anticipate a movement of poor quality water farther into the Everglades than ever before. What will be the fate of those contaminants? How slowly or quickly will they move through the central and southern Everglades? How will the natural processes of surface-subsurface water exchange, and resulting biogeochemical transformations, affect the changing water quality? Currently most water-quality models in the Everglades have relatively rudimentary representations of the solute transport mechanisms due to the lack of informative field studies. Knowledge of the processes that affect solute and fine-particle movement, such as advection, dispersion, and hydrologic retention resulting from surface-subsurface exchange, are integral to understanding how the distribution of contaminated water in the Everglades will change over time. We believe that a field approach rooted both in fundamental solute transport experiments, as well as larger-scale extrapolations using the radium tracer, has the greatest chance for success for extrapolation to larger scales. To that end we expect all ongoing and future water-quality investigations to be informed by our work. The detailed bromide tracer experiments and extrapolation to larger scale using radium will guide the development and parameterization of water-quality models such as ELM (Carl Fitz, SFWMD). At the same time, our collaborators (Bill Orem, GD; Evelyn Gaiser, FIU-SERC; etc.) will provide the ecological and geochemical process measurements that will determine the rates of biogeochemical transformation that affect contaminants such as sulfate and nutrients.
Our project is still active in publishing results from on-going (but nearly completed) investigations in Water Conservation Area 2A and Taylor Slough, and will add to that production line new products from FY03 activities in Shark Slough. Our philosophy is to publish comprehensive USGS reports and open file data reports as quickly as possible for the south Florida community, but also to publish extended results and interpretations in the peer-reviewed literature of professional journals. We consider this to be a critical step for USGS hydrologists, both to gather feedback from as well as acceptance from the international scientific community.
In FY03/04 we plan to continue reporting our results, again using the model of publishing in a variety of outlets including USGS interpretive reports, open-file data reports, and journal articles that will make the detailed data sets and the process interpretations available to the widest possible scientific community.
The first product from watershed-scale application of the radium tracer is expected in FY03, presenting the theory and results from the field test in Taylor Slough. The second product will document results from the bromide tracer test in the FIU-SERC flumes. The third product will combine bromide results with a watershed-scale assessment of surface-subsurface interactions in Shark Slough. All fieldwork will be completed by early FY04 and all analysis and writing will be completed in FY05. The publication outlets are USGS reports and journal articles in Water Resources Research and Limnology and Oceanography.
Collaborators: Jim Saiers (Yale University), Evylyn Gaiser, (FIU)
Clients: Current users include TIME model developers (USGS-Langevin, Swain, and Schaffranek), South Florida Water Management Model Developers (SFWMD-Obeysekera), ENR Nutrient Balance Analyists (SFWMD-Chimney), and STA Design Reassessment Group (SFWMD-Kadlec/Walker and DB Associates). In the near future we expect our new work on tracer experimentation in the wetlands to be of tremendous value to water-quality and biogeochemistry modelers and experimentalists, such as Carl Fitz (SFWMD), who operates the ELM water quality model, and Evelyn Gaiser and others at FIU who operate the FIU flume phosphorus dosing study.
B. WORK PLAN
Title of Task 1: Hydrologic Transport Processes Affecting Solute Movement and Retention in the Everglades
Work to be undertaken during the proposal year and a description of the methods and procedures:
The principal work to be conducted in FY03 is a detailed experimental study of solute transport in Shark Slough. This experiment is needed as a critical test of our assumptions regarding interpretations of the larger scale distribution of radium in the wetland. Conducting the tracer experiments in the FIU/SERC flumes has the added benefit of connecting us to the phosphorus dosing study in a way that is mutually beneficial to USGS and our university collaborators in the Everglades. We should note that we have in hand all the permissions and permits to proceed with the work.
Our plan involves releasing by steady injection (for a period ranging between 4 and 24 hours) a small amount of salt solution (sodium bromide) in "flumes" in Everglades National Park. We will track both the downstream movement and longitudinal spreading of the tracer in surface water, as well as the exchange between surface water and peat porewater. Our collaborator, Jim Saiers from Yale University, will be conducting a co-injection of fine (neutrally-buoyant) latex particles to learn about processes affecting transport of fine particulate organic matter. As outlined above, we have particular interest in quantifying the rate and extent to which surface water and subsurface porewater are exchanged. This information is embedded within the surface-water tracer measurements but will be verified independently through measurements of concentrations of the bromide tracer in porewater of the peat. Our modeling will account for advection and longitudinal dispersion of solute in surface water, as well as the effects of exchange with peat porewater. Jim Saiers will have primary responsibility for measurement and modeling of fine particulate transport.
We have proposed doing these tracer experiments in the Florida International University 100-m experimental phosphorus dosing flumes located in Shark Slough. The motivation is to not only take advantage of existing and appropriate infrastructure for our experiments, but also to support and collaborate with FIU and other USGS and university scientists toward an understanding of the dynamics of fine particle and phosphorus transport and cycling in the Everglades. As noted above, our ideas have been greeted enthusiastically by the FIU project chief on the dosing study (Evelyn Gaiser - FIU), and we have all the permissions and permits needed to proceed in hand.
At larger spatial scales our strategy is to modify the site-specific radium isotopic tracer technique that we previously developed to quantify ground water and surface water interactions at a water shed scale. The first product of our work with radium was recently accepted for publication in Limnology and Oceanography. To accomplish our goal of scaling up we will need to extend our site-specific method using the radium tracer in a way that will allow us to quantify interactions between surface and subsurface water along a surface-water "flowpath" in the main flow-ways in Shark Slough and Taylor Slough. Broad, kilometer-scale sampling of the radium tracer and other physical and biogeochemical parameters have already been completed in Taylor Slough. Similar work will be conducted in Shark Slough beginning either in the 1st or 2nd quarter of FY03. The results of these synoptic investigations of the large-scale distribution of radium will by modeled with calibration using results from smaller-scale (100-meter) tracer experiments in the FIU-SERC 100-m flumes in Shark Slough.
Planned Outreach in FY03:
GEERS, April 2003
Water Quality Workshop or Hydrologic Modeling Workshop , 2003
We anticipate continued interaction with SFWMD concerning our now largely completed investigations of interactions between ground water and surface water in the north-central Everglades. Interactions continue with the environmental engineering group analyzing nutrient uptake and storage in constructed wetlands (Mike Chimney - SFWMD), The design reanalysis group for Stormwater Treatment Areas (Robert Kadlec and D.B. Associates), and the Hydrologic Systems Group (Jayantha Obeysekera - SFWMD) who now more than ever need to be concerned with detailed verification of the South Florida Water Management Model in specific areas of the Everglades where restoration projects will have appreciable effects on hydrology. We also expect to begin more frequent dialogues with water-quality and biogeochemistry modelers and experimentalists, such as Carl Fitz (SFWMD), who operates the ELM water quality model, and Evelyn Gaiser and others at FIU who operate the phosphorus dosing flume study.
C. Related Work:
1996 - 1998 Cooperative Agreement C-6661 with the South Florida Water Management District, Groundwater-Surface Water Exchange Fluxes in the ENR Project.
1999 - 2003 Cooperative Agreement C-10719 with the South Florida Water Management District, Geochemical Mass-Balance Modeling in WCA-2A to Quantify Interactions Between Groundwater and Surface Water.