Project Work Plan

Study Title: Effect of Water Flow on Transport of Solutes, Suspended Particles, and Particle-Associated Nutrients in the Everglades
Study Start Date: October 2002 Study End Date: September 2006
Web Sites: http://sofia.usgs.gov/projects/susparticles/; http://sofia.usgs.gov/projects/wtr_flux/ http://sofia.usgs.gov/sfrsf/entdisplays/waterlevels/; http://sofia.usgs.gov/exchange/harvey/harveyDATA.html; http://water.usgs.gov/nrp/jharvey/site/index.html
Location (Subregions, Counties, Park or Refuge): Northern, Central, and Southern Everglades (Palm Beach, Broward, Miami-Dade)
Funding Source: USGS Greater Everglades Priority Ecosystems Science (GE PES)
Other Complementary Funding Source(s): None
Principal Investigator(s): Jud Harvey and Greg Noe (USGS, Reston), and Jim Saiers (Yale Univ.)
Study Personnel: Jennifer O'Reilly, Joel Detty, Ying Qiu
Supporting Organizations: USGS, SFWMD, NPS/Everglades National Park
Associated / Linked Studies:
Tides and Inflows at the Mangrove Ecotone (TIME): http://time.er.usgs.gov/;
Integrated Geochemical Studies in the Everglades: http://sofia.usgs.gov/projects/wetland_seds/, http://sofia.usgs.gov/projects/evergl_merc/;
Freshwater Flows into Florida Bay: http://sflwww.er.usgs.gov/projects/freshwtr_flow/;
Florida Coastal Everglades Long-Term Ecological Research: http://fcelter.fiu.edu/

Overview & Objective(s):

A key measure of success in the Everglades restoration is protecting water quality while increasing the quantity of water flowing through the Everglades. The restoration's goal of increasing surface-water flow through the wetlands could have the unintended consequence of transporting contaminants farther into the Everglades than ever before. Thus, the need to augment water delivery will at times inevitably result in using water with higher than desirable total dissolved solids, particulate organic matter, sulfate, nutrients, and mercury. In addition, greater water flows may increase transport of those contaminants farther into the wetlands than ever before. Our investigation seeks a better understanding of the fundamental processes that affect the rates at which contaminants are transported in wetlands, focusing especially on critical unknowns - 1) rates of contaminant transport in association with fine suspended particles, and 2) rates of solute exchange between surface water and storage areas reservoirs in relatively stagnant surface waters (in thick vegetation and subsurface pore water in peat). Our studies are planned to be the definitive experimental investigations of solute and particle transport in the Everglades. Results will have significant value to forecasting the possible future effects of restoring higher flows on water quality throughout the Everglades.

The objectives of the study are:

• To quantify through detailed field experiments previously unstudied processes in the Everglades, such as rates of fine-particle movement and filtration by vegetation as well as advective solute exchange between surface water and zones of solute storage in relatively stagnant waters (in areas of thick vegetation and in peat pore water). Our study focuses on determining the effects of these processes on chemical reactions of the contaminants as well as overall effects on downstream transport. At least initially, the emphasis will be on improved understanding of factors influencing transport of dissolved and fine particle forms of phosphorus.
• To apply the new knowledge gained from field measurements first in our own transport models (which are necessarily limited in time and space) and then to encourage application in more widely used water-quality models (e.g. DMSTA, ELM), and water quality models currently in development (e.g. extension of USGS SICS model in Taylor Slough). The goal is more accurate simulation of the effects of restoration on Everglades water quality, thus allowing more reliable use of water-quality models for prediction of the effects of restoration.
• To guide the use of improved water-quality models to estimate potential rates of transport, storage, and remobilization of phosphorus (and other contaminants) in WCA-2A, Shark and Taylor Sloughs in Everglades National Park, and Loxahatchee Wildlife Refuge, with a goal to predict potential rates of downstream movement of phosphorus in these systems under “restored” flows.

Specific Relevance to Major Unanswered Questions and Information Needs Identified: (Page numbers below refer to DOI Science Plan.)

This study supports critical science needs in the following four projects in the DOI Everglades Science Plan: (1) Water Conservation Area 3 Decompartmentalization and Sheetflow Enhancement, (2) Arthur R. Marshall Loxahatchee NWR (WCA-1) Internal Canal Structures, (3) Comprehensive Integrated Water Quality Feasibility Study, and (4) Landscape-Scale Modeling Study.

One of the most important aspects of our work is determining the role of transport of fine suspended particles in controlling storage, transport, and transformation of phosphorus (and other contaminants) in the surface water of Everglades wetlands. Regional differences will be addressed through measurements at one site in central Arthur R. Marshall Loxahatchee (WCA-1), three sites along the nutrient enrichment gradient in WCA-2A, and one site each in Shark Slough and Taylor Slough in Everglades National Park. Interactions between phosphorus biogeochemistry, particle transport and filtration, and water flow velocity will be investigated through field-tracer experimentation using carefully controlled injections of solute and particulate tracers. The goal of tracer experiments is to determine the fate of particulate matter and associated phosphorus under different flow conditions. Modeling by our group will be required first to interpret the results of tracer experiments, with the goal being to produce a fundamental set of transport parameters representing the role of fine suspended particles and storage of water and solute in relatively slow-moving areas of thick vegetation and subsurface pore water. At that point we expect that our modeling concepts and parameter sets will be implemented in the more comprehensive water-quality models and landscape ecosystem models (such as DMSTA and ELM) that are being used to adaptively guide the restoration. In this way the knowledge gained from our detailed experiments will be “scaled-up” for application at larger spatial scales and at longer temporal scales. The first application we can envision (probably beyond the FY05 timeframe) is the testing of the role of fine suspended particles in phosphorus cycling along the “Nutrient Threshold Transect” in Water Conservation Area 2A, and the main flow axes of Taylor Slough and Shark Slough in Everglades National Park, and in Loxahatchee Wildlife Refuge (WCA-1). If successful, we envision the incorporation of our parameters into model applications throughout the Everglades. In particular, the results of these studies will be crucial in predicting the effects of WCA-3A Decompartmentalization Project (DOI Science Plan p. 66). This study will also provide key scientific data to the Loxahatchee Internal Canal Structures Project (p. 39), Comprehensive Integrated Water Quality Studies (p. 84), and Landscape-Scale Modeling Study (p. 81).

Status: Active

Recent Products:

Saiers, J.E., Harvey, J.W., and Mylon, S.E., 2003, Surface-water transport of suspended matter through wetland vegetation of the Florida Everglades. Geophysical Research Letters 30(19), 1987, doi:10.1029/2003GL018132.

Noe, G.B., Scinto, L.J., Taylor, J., Childers, D.L., and Jones, R.D. 2003, Phosphorus cycling and partitioning in an oligotrophic Everglades wetland ecosystem: a radioisotope tracing study. Freshwater Biology 48(11):1993-2008.

Harvey, J.W., Krupa, S.L., and Krest, J.M., 2004, Ground water recharge and discharge in the central Everglades, Ground Water, in press

Harvey, J.W., Newlin, J.T., Krest, J.M., Choi, J., Nemeth, E.A., and Krupa, S.L., 2004, Surface-Water and Ground-Water Interactions in Water Conservation Area 2A, Central Everglades, USGS SIR 2004-5069 (conditionally approved);

Additional fact sheets and data reports

WORK PLAN

Title of Task 1: Effect of Water Flow on Transport of Solutes, Suspended Particles, and Particle-Associated Nutrients in the Everglades
Task Funding: USGS Greater Everglades Priority Ecosystems Science (GE PES)
Task Leaders: Jud Harvey, Greg Noe, Jim Saiers
Phone: (703) 648-5876
FAX: (703) 648-5484
Task Status (proposed or active): Active
Task priority: High
Task Personnel: Jennifer O'Reilly, Joel Detty, Ying Qiu
Task Summary and Objectives: See Overview and Objectives above

Work to be undertaken during the proposal year and a description of the methods and procedures:

1. Characterize regional patterns in physical properties and chemistry of fine suspended particles through a regional program of sampling in the Everglades to determine the total concentration, size distribution, elemental composition, and source of fine suspended particles. These characteristics and processes will be measured in contrasting peat and marl forming wetlands, and in wetlands with contrasting impacts of phosphorus pollution. Regional differences will be addressed through measurements at one site in central Arthur R. Marshall Loxahatchee (WCA-1), three sites along the nutrient enrichment gradient in WCA-2A, and one site each in Shark Slough and Taylor Slough in Everglades National Park. The DOI Science Plan highlights the need to understand the influence of hydrology on nutrient and contaminant transport and cycling. The National Academy of Sciences has also emphasized the importance of sediment transport to understanding and restoring the Everglades. Knowledge of the physical and chemical characteristics of suspended sediment is necessary for efforts to predict sediment transport and fate, as well for associated contaminants, and will enable efforts to optimize Everglades restoration. Information on suspended sediment characteristics will also be applied in Objective #3, below.
2. The interaction between phosphorus biogeochemistry, transport and filtration of fine suspended particles, and water flow velocities, will be addressed through carefully controlled injections of solute and particulate tracers. The goal is to determine in detail the fate of solutes and fine particulate matter under different flow conditions and to identify the specific physical and biological features and processes responsible for the observed levels of transport and storage. These detailed experiments are to be conducted at the spatial scale of approximately 10 m and the time scale of several days. Results of those experiments must be modeled in detail to produce the parameters describing what is learned about the role of various controlling processes including particle sources, size classes, and phosphorus content; transport and filtration rates of particles, water and solute storage in relatively slow moving water in zones of thick vegetation and in subsurface pore water; and chemical reactions that phosphorus undergoes in its various dissolved and particulate forms. This information is critical for improving the modeling of the cycling and transport of dissolved and particulate contaminants in the Everglades. This information will also be applied in Objective #3, below.
3. The first step toward building more reliable water-quality models begins with our own models that must be constructed to interpret the results of our transport experiments. Those modeling efforts will “parameterize” specific processes such as rates of transport and filtration of fine suspended material. These models will necessarily be limited to small spatial scales (tens of meters) and relatively short time scales (days). Although beyond the scope of FY05, the next step is to “scale-up” the transport parameters from our detailed models for application in models with larger spatial scales (tens of kilometers) and longer temporal scales (several months).
4. A possible next phase of modeling (in a future fiscal year) involves modeling at larger spatial and longer timescales, which could be begun by upgrading our previous (Saiers' and Harvey's) simulations of flow and transport processes by refining them for the purpose of modeling phosphorus transport. Under consideration for initial model applications would be the “Nutrient Threshold Transect” in Water Conservation Area 2A, and the main flow axes in Taylor Slough and Shark Slough, Everglades National Park. If constructed by us, these models would be relatively simple, with flow and mixing conceptualized either in a one-dimensional (longitudinal dispersion) framework or possibly in a two-dimensional framework by adding the vertical dimension. With the exception of the new parameters relating to particle transport and solute storage, the majority of biogeochemical reactions and fluxes of phosphorus would follow previous models and experiments. What we would be testing is the importance of these new parameterizations of fine suspended particle (and associated phosphorus) fluxes and particle filtration, and movement of dissolved phosphorus into and out of storage in thick vegetation and peat pore water. Even though these models will be relatively simple, they will be substantially more sophisticated in their processes than some of the existing models for phosphorus transport (such as DMSTA), particularly in the specification of the form of phosphorus (dissolved or particulate), the transport characteristics of each form of phosphorus, and the associated storage times and its effects on downstream transport. Because the modeling will be based on our definitive experimental results, we expect to quickly develop new understanding of the major processes affecting phosphorus retention times as trapped particles and in pore water and effects on the rate at which new loads of phosphorus will be propagated through the wetlands under higher flows.
5. Since we are primarily experimentalists, even the modeling efforts described in 4) above will not be sufficient in the coming years to meet the needs of the scientific community supporting the Everglades restoration. For that reason our work must be coordinated with work by full-time modelers in the USGS Reston and Miami offices and with modelers in the South Florida Water Management District. We expect that some of our most productive collaborations could be through interactions with the authors and users of the DMSTA water-quality model (Walker and Kadlec, for SFWMD) and the Everglades Landscape Model (Fitz, SFWMD). We also envision interactions with modelers at USGS, beginning with the expansion of the SICS hydrology model to incorporate a phosphorus transport module. Although Loxahatchee (WCA-1) would not immediately be considered for transport modeling in FY05, we could explore possibilities for transport modeling collaborations in future fiscal years, with consideration given both to a transect running perpendicular from the internal canals to central WCA-1, as well as collaborations in the LILA experimental basins located just outside WCA-1.

SUMMARY: Our proposed experiments and modeling are fundamental to building a reliable predictive capability of how the Everglades will respond to the higher flows that are central to the restoration. Our proposed combination of empirical and modeling research will support several of the critical information needs identified by the National Academy of Science and DOI Everglades Science Plan. This work will have the most bearing on the WCA-3A Decompartmentalization Project. Improved understanding of the controls on sediment, nutrient, and contaminant transport will identify some of the hydrologic, chemical, and biologic linkages that shape the pre-drainage and current landscape. This information is necessary for understanding the critical factors that sustain the ridge and slough landscape and ecosystem function, as well as for predicting the effects of changes in hydrologic connectivity (a focus identified as important by the National Academy of Science). Our initial focus on phosphorus transport will support the Comprehensive Integrated Water Quality Feasibility Study. Finally, the information gained on particle and solute transport will aid critical modeling efforts that support the Loxahatchee Internal Canal Structures Project and Landscape-Scale Modeling Study. In conclusion, our proposed work will support several of the research needs that have been identified as critical to Everglades restoration efforts.

Specific Task Product(s):

Journal manuscripts (FY05):

Harvey, J.W., Newlin, J.T., Krupa, S.L., Modeling decadel timescale interactions between surface water and shallow ground water in the central Everglades, Florida, USA, Journal of Hydrology, submitted.

Harvey, J.W., Saiers, J.E., and Newlin, J.T., Solute Transport and Dispersion in Wetlands of the Everglades, South Florida. Water Resources Research, submitted.

Noe, G.B. and Childers, D.L. The effects of enrichment on Everglades wetland ecosystem phosphorus budgets. To be submitted to Ecosystems by December 2004.

Noe, G.B., Saiers, J.E., and Harvey, J.W. Characterization of suspended particles in Everglades wetlands. To be submitted to journal by September 2005.