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projects > groundwater-surface water interactions and relation to water quality in the everglades > 1999 proposal

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

Project Proposal for 1999

Project number: WRD 4384-17800 USGS Geologic Division Continuing Project Work Plan - FY 1999 IDENTIFYING INFORMATION
Project title: Groundwater-Surface Water Hydrologic Exchange Fluxes and Relation to Mercury, Sulfate, and Nutrient Cycling in the Everglades
Geographic area: South Florida
Project start date: FY 1996
Project end date: FY 2000

Project chief: Judson W. Harvey
Region/Division/Team/Section: Eastern/WRD/B ranch of Regional Research
Phone: 703-648-5876
Fax: 703-648-5484
Mail address: USGS, 430 National Center, Reston, VA 20192
Program(s)/element(s)/task(s) (show percent distribution if more than one element/task). If submitting to more than one program, include element(s)/tasks from each program here:

South Florida Program:
(50%) Element 2: Modeling and Support Studies for SICS (Southern Inland Coastal Systems)
Task 2.7: Measuring and Modeling Hydrologic fluxes Between Ground and Surface Water in Taylor Slough.
(50%) Element 4: Regional Mercury, Geochemistry, and Water Quality Assessment
Task 4.6: Groundwater-Surface Water Interactions in Northern Everglades.

Project summary: A brief (<100 words) summary written to be understood by a nonspecialist. State the issues to be addressed, the objectives of the project, significance to scientific questions and land-management and policy issues, and benefit to the Nation, all in terms that do not require technical translation. This paragraph will be used to describe this project in the Program and Division science plans.

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 determining effects on transport and transformation of mercury and nutrients in the Everglades. The overall aim of this project is to quantify hydrologic exchange fluxes between groundwater and surface water and its effects on transport of mercury and nutrients at research sites in the Everglades Nutrient Removal Area (ENR), Water Conservation Area 2A (WCA-2A), and Taylor Slough in Everglades National Park. The research furthermore relates ground and surface water interactions and fates of mercury and nutrients to past, present, and proposed management of surface-water levels and flows in the Everglades.

Project objectives and strategy: More detailed/technical than the project summary, describing BRIEFLY the technical goals and approaches to be used over the LIFETIME of the project.

The objectives of this project are;

(1) Develop or adapt several independent methods (a hydrologic method and a solute-tracer method) to quantify vertical fluxes of water and solute between ground and surface water at specific research sites in the Everglades.
(2) Combine results from above investigations with water budget and solute-tracer concentrations from surface and groundwater to constrain area-averaged estimates of hydrologic exchange between groundwater and surface water. Use the improved water budget models with interactions between ground water and surface water to refine solute mass balances for mercury, sulfate, and nutrients in the study wetlands,
(3) Identify the relative importance of factors that influence interactions of groundwater and surface water and effects on transport and transformations of mercury, sulfate, and nutrients.

Overall Strategy, Study Design, and Planned Major Products (single paragraph):

A combined water balance and environmental tracer methodology is used to determine vertical exchange of water and solute at research sites in the Everglades system. The initial research in FY96/97 began at fourteen sites in the Everglades Nutrient Removal Area (ENR) and at seven sites in the north-central portion of Water Conservation Area 2A (WCA-2a). Fieldwork was expanded in FY97/98 to include a single site in WCA-2b, a single site in WCA-3a, and five sites in Taylor Slough.

In total, flux measurements have been made at more than 30 study sites where mercury and nutrient fluxes are under study, including ENRI WCA-2a. and Taylor Slough wetlands. Groundwater hydraulic head and chemical measurements have been made at 60 sites; in collaboration with Mike Reddy (USGS, WRD, Boulder) peat porewater chemistry has been measured at six depths at 7 sites for almost 3 years. The major benchmarks of progress for the study are:

1) Establish research sites on transects across the wetland interior in ENR, WCA-2A, and Taylor Slough (and single sites in WCA-2B and WCA-3A). Measure porewater solute concentrations and vertical seepage and quantify vertical fluxes of groundwater and surface water across the sediment interface using these two independent sources of information. Measure groundwater hydraulic heads and compute vertical hydraulic gradients (that indicate the direction of vertical fluxes and changes in that direction over time). Also measure hydraulic conductivity of the peat and layers within the aquifer and measure groundwater chemical and isotopic concentrations for use as tracers to quantify area-averaged fluxes to surface water,
2) Combine the site-specific vertical flux estimates described above with other water budget data (surface-water flow, precipitation, evapotranspiration) and other chemical data from surface-water locations. Use expanded data sets to constrain area-averaged water and chemical mass balance models in ENR, WCA-2a, and Taylor Slough,
3) Relate vertical exchange fluxes of water, mercury and nutrients between ground and surface water to past and current water-level management strategies. Consider factors such as hydrogeologic characteristics, regional water balance, and effect of management of water levels in canals and in WCA-l.
4) Post results in archival database on the USGS web site, publish methods and interpretations in USGS reports and journal papers, and summarize interpretations in the two USGS synthesis reports.

Potential impacts and major products: Describe expected outcomes, both scientific and management/policy related. What scientific questions and land-management and policy issues does this project help answer? Why is it important to Program prioritiesâ? What products will you produce to contribute to the desired outcomes?

The present project is developing, testing, and documenting tools to determine surface-groundwater hydrologic exchange fluxes. Specific results from ENR, WCA-2A, and Taylor Slough areas are being reported rapidly to collaborators, and as needed to cooperators. Results are also being prepared for posting on web sites and publication in USGS reports, synthesis documents, and peer-reviewed literature.

Our research clearly has shown that that compartmentalizing the Water Conservation Areas has enhanced interactions between groundwater and surface water throughout the wetlands of the northern Everglades. That result has major implications in several key management programs in South Florida, including the following clients and cooperators.

  • SFMSP (South Florida Mercury Science Program with representation by SFWMD, USGS, and State of Florida DEQ),
  • SFWMD Resource Assessment Division, Mercury Program,
  • USGS South Florida Mercury and Biogeochemistry Synthesis Project,
  • USGS Southern Inland Coastal System Synthesis Project,
  • SFWMD Stormwater Treatment Area (STA) Functional Assessment Group, responsible for predicting hydrologic transport and water quality in six major constructed wetlands,
  • SFWMD Hydrologic Modeling Systems Division, responsible for modeling for the Army Corps Surface-Water Storage and Conveyance Restudy (usually referred to as the Restudy),

Collaborators, clients (Names, affiliation, and roles of internal and external users of information generated by project):

(1) Larry Fink, Resource Assessment Division, SFWMD, and member of the SFMSP (South Florida Mercury Science Program). Mercury mass balance studies in the Everglades depend on the present projectâs hydrologic flux data and mercury measurements in groundwater and porewater in ENR, WCA-2A and Taylor Slough to close the mercury mass balance,
(2) David Krabbenhoft. Leader ÷ USGS Mercury and Biogeochemistry Program in the Everglades, WRD, Madison, WI. USGS Mercury Synthesis Project in FY99 and FY00 depends on the present project to document the role of surface-groundwater interactions and effects on mercury cycling in the Everglades.
(3) Ray Schaffranek, Eric Swain, and Tom Smith, Co-leaders ÷ USGS Southern Inland Coastal System (SICS) Synthesis Project. Groundwater interactions with surface water are a significant unknown in Taylor Slough and this synthesis project is depending on the outcome of present studies to quantify surface-groundwater interactions in Taylor Slough.
(4) Bill Orem. USGS. Project Chief, Sulfur and Nutrient Cycling in the Everglades, GD, Reston, VA. Oremâs research project to trace sources of sulfate and phosphate in the northern Everglades depends on the present projects hydrologic and chemical data and groundwater samples collected for nutrients and sulfur isotopic analysis.
(5) Jaye Obesekera. Chief- Hydrologic Modeling Systems Division, SFWMD. Dr. Obesekera enthusiastically supports this first of its kind effort to collect basic hydrogeological data in Water Conservation Areas. The data collected by the present project have been judged to be appropriate for constraining and calibrating SFWMD hydrological models of the Water Conservation Areas to investigate various scenarios considered under the ACE Restudy.
(6) Helena Solo-Gabriele. Prof., U. Miami and subcontractor to USGS, Miami Subdistrict. Prof. Solo-Gabriele is now using the seepage-meter method developed by the present project on her study of levee underflow along the L-30 levee in Dade County.
(7) Peter Swart and Rene Price, Prof. and PhD. Student, U. Miami. These U. Miami investigators are funded by SFWMD to investigate groundwater processes in Taylor Slough and are collaborating with USGS investigators (Harvey, Fitterman, etc.) to quantify fluxes of water between groundwater and surface water in Taylor Slough.
(8) Mike Reddy, USGS, Project Chief, Redox cycling in the Everglades, WRD, Boulder, CO. I developed the porewater sampling method used by this group and am cooperating to develop the transport models for vertical transport and reaction of solutes.
(9) Charles Holmes, USGS Project Chief, Isotope dating, WRD, St. Petersburg. In FY98 I began using short-lived radium isotopes to quantify groundwater discharge to freshwater wetlands in Taylor Slough. In FY99 I will continue that work and will also cooperate with Chuck Holmes, who will use radium isotopes to investigate groundwater-surface water exchange in Florida Bay.

Time line (FY 1999 to project end): List MAJOR tasks and deliverables by fiscal year and indicate key staff responsible for each.

FY 1999 Major Tasks: Statement of the work to be undertaken in FY 1999 and a description of the methods and procedures.

(1) Fieldwork: Fieldwork that began in FY96 in northern Everglades to quantify hydrologic fluxes between groundwater and surface water is on schedule to be completed in FY98. Fieldwork in Taylor only began in FY97 and will not be completed until mid-FY99.
(2) Chemical analyses, QA/QC, Data Reduction: Chemical analyses, QA/QC, and data reduction will be needed throughout FY99 to achieve closure on fieldwork.
(3) Modeling: Modeling vertical fluxes of water and solute through peat at specific locations in ENR and WCA-2A began in FY98 and will continue and expand in FY99 to address the need for area-averaged estimates of ground-surface water exchange and solute fluxes. The increased scope of work will be accomplished by combining surface-water hydrologic fluxes at major inflows and outflows with precipitation and evapotranspiration data, and with chemical data acquired from surface water and from new groundwater wells first sampled by this project in FY98. The purpose of modeling is (a) to quantify area-averaged hydrologic fluxes between groundwater and surface water in ENR, WCA-2A, and in Taylor Slough. (b) apply the mass-balance models to trace the source of sulfate and fate of phosphorus in ENR and WCA-2A (with Bill Orem, USGS/GD), and (3) apply the mass-balance models to determine the fate of mercury in the ENR (with Sue King and Dave Krabbenhoft, USGS/WRD).
(4) Data Analysis and Modeling Summary, Database Management, and Contribution to Archival Database on Web: Contribution of metadata for all research activities will be completed in FY98. QA/QC of summarized data and contribution to archival database will begin in FY99 and be completed in FY2000.
(5) Publication: A USGS methods report is in review, a final report on groundwater-surface water interactions in the northern Everglades work is scheduled for FY99, and 2 journal articles are planned for FY99.

FY 1999 deliverables/products: Describe in more detail the specific deliverables/products that will result from this work in FY 1999.

(1) A USGS methods report by Harvey et al. is currently in review and will be published in FY98. The purpose of the report is to allow a quick outlet for a complete description of methods used in groundwater-surface water investigations. The report describes testing of methods and procedures to estimate limits of detection and uncertainty at a level of detail that is inappropriate for journals but appropriate for a USGS report.
(2) A USGS interpretive report on groundwater-surface water interactions in the northern Everglades will be completed in FY99 for the SFWMD. Resource Assessment Division. SFWMD funded the present project in entirety in FY96 and at a significant level in FY97 and FY98. The final report provides a summary of vertical flux data and applies those findings to the development of groundwater flux estimates of mercury in ENR and WCA-2a.
(3) A journal article is planned in FY99 that summarizes the findings of broad interest on hydrologic interactions between groundwater and surface water in the northern Everglades.
(4) A second journal article in FY99 is also planned that focuses on identifying the interactions between vertical hydrologic fluxes, sulfate cycling and mercury transport and transformation at ENR (in collaboration with King. Krabbenhoft. Orem, and Reddy or Schuster).

FY 1999 outreach: Emphasizing FY 1999, describe plans to address client requirements, decisions, and deadlines. New directions or major changes for FY 1999 (if applicable):

There are no significant changes in project goals or departures in project plans in FY99. To accommodate the shifting emphasis toward modeling analysis there is a change in the mode of operation on this project, from a field program with personnel located primarily in Florida, to a hydrologic modeling program. with personnel located primarily in Reston, VA.

FY 1998 accomplishments and outcomes, including outreach:

(1) Identified for the SFMSP (South Florida Mercury Science Program), SFWMD mercury program, and USGS South Florida Mercury and Biogeochemistry synthesis project that there is a significant loss of total dissolved mercury by outflow from surface water to groundwater in the ENR project area. This is a key finding needed to achieve closure in the ENR mercury budget,
(2) Determined for the USGS Mercury and Biogeochemistry Program (Krabbenhoft-Leader; Orem, Project Chief of Sulfur and Nutrient Cycling Project) that groundwater discharge from the surficial aquifer to wetlands historically was a source of sulfate to wetlands of the northern Everglades. Sulfate is important because it is linked with methylation of mercury by sulfate reduction in the peat sediment. Groundwater flow through peat affects mercury cycling by delivering new sulfate and flushing sulfide, and by flushing methyl mercury to surface water.
(3) Quantified for the USGS Southern Inland Coastal Systems Project (Shaffranek, Swain, and Smith ÷Co-leaders) a shallow flow of groundwater from the ENP pinelands beneath Ingraham Highway into Taylor Slough that augments flow in Taylor Slough by as much as a third. This finding is particularly important because flows beneath Ingraham Highway are ungageable. At present most models of Taylor Slough are treating the Ingraham Highway as a no-flow boundary and require this projects information.
(4) Demonstrated to the SFWMD Hydrologic Modeling Systems Group (Obesekera ÷ Chief) and SFWMD Stormwater Treatment Area Group that management of WCA-l exerts a regional influence on groundwater-surface water interactions, causing upward fluxes through peat near to WCA-1 and downward fluxes through peat far from WCA-l. This information will affect monitoring and management decisions into the next century as STAâs come on line during the next ten years and when recommendations of the SFWMD/Army Corps of Engineers Restudy are implemented.

FY 1998 deliverables, products completed:
(1) Metadata for all sites and measurements in ENR. WCA-2A, WCA-2B, WCA-3A, and Taylor Slough to be completed in FY98.
(2) FY98 Biblography:

Bates, A.L.. Orem. W.H., and Harvey, J.W., 1998. Tracing sources of sulfate in the northern Everglades using sulfur isotopic compositions, EOS, Transactions of the American Geophysical Union, 79(17): S93.

Harvey. J.W., Krupa, S.L., Mooney, R.H.. Schuster, P., 1998, Are groundwater and surface water connected by vertical hydrologic fluxes through peat?, EOS. Transactions of the American Geophysical Union, 79(17): S87.

Harvey. J.W., Krupa. S.L.. Mooney, S.L.. and Gefvert, C.. 1998. Interactions between ground water and surface water in the Everglades Nutrient Removal Area that affect mercury transport and transformation, Annual Meeting of South Florida Mercury Science Program Investigators, West Palm Beach, FL, May 18 - 20, 1998.

Harvey. J.W. ,Mooney, R.H.. and Krupa. S.L., 1998, Use of seepage meters to determine the vertical flux of ground water and surface water through wetland peat in the Florida Everglades, U.S. Geological Survey Water Resources Investigations Report 98-xxxx, 50 pages, currently in USGS regional review.

Krupa. S.L., Harvey, J.W., Gefvert, C., and Giddings, J., 1998, Geologic and anthropogenic influences on groundwater-surface water interactions in the northern Everglades, EOS, Transactions of the American Geophysical Union, 79(17): S 176.

Orem, W.H., Bates, A.L., Lerch, H.E., and Harvey, J.W., 1998, Sulfur geochemistry of the Everglades: sources, sinks, and biogeochemical cycling, Annual Meeting of South Florida Mercury Science Program Investigators, West Palm Beach, FL, May 18 - 20, 1998. Abstract published with meeting program.

Names and expertise (e.g. carbonate petrology) of key project staff (list by fiscal year for duration of project):
FY 1999
senior hydrologist
hydrological flow and transport modeler
physical scientist technician
physical science aid (summer)

senior hydrologist
hydrological flow and transport modeler
physical science aid (summer)

Names of Key Project Staff (list by fiscal year for duration of project):
FY 1999
Judson Harvey, WRD. Reston.(30%)
Jungyill Choi, contract employee, Reston. (100%)
Robert Mooney. WRD, Miami (10%)
Jonah Jackson, summer student, Reston, (25%)
Judson Harvey. WRD. Reston, (30%)
Jungyill Choi, contract employee, Reston, (100%)
Jonah Jackson, summer student, Reston, (25%)

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