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Project Summary Sheet

U.S. Geological Survey, Greater Everglades Priority Ecosystems Science (GE PES) Initiative

Fiscal Year 2005 Study Summary Report

Study Title: Effect of Water Flow on Transport of Suspended Particles and Particle-Associated Nutrients in the Everglades
Study Start Date: October 2002 Study End Date: September 2006
Web Sites:;;;
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) Initiative
Principal Investigator(s): Jud Harvey and Greg Noe (USGS, Reston), and Jim Saiers (Yale Univ.)
Study Personnel: Jennifer O'Reilly, Ying Qiu, Joel Detty
Supporting Organizations: USGS, SFWMD, NPS/Everglades National Park
Associated / Linked Studies: Tides and Inflows at the Mangrove Ecotone (TIME);
Integrated Geochemical Studies in the Everglades,;
Freshwater Flows into Florida Bay

Overview & Objective(s): A key measure of success in the Everglades restoration is protecting water quality while increasing water quantity. The restoration's goal of increasing flow through the wetlands could have the unintended consequence of transporting contaminants farther into the Everglades than ever before. The need to augment water delivery to the Everglades could at times result in the use of water with higher than desirable total dissolved solids, particulate organic matter, sulfate, and nutrients. Also, contaminants stored previously in the subsurface beneath the northern and central areas of the Everglades are now being remobilized and transported to points downstream. The effect that restored water flows will have on future rates of remobilization of contaminants from sediment, or on future rates of downstream transport of contaminants, are not well understood. Our experimental investigations will provide the fundamental information needed to conduct valid simulations to predict future water quality under restoration. The objectives of our investigations are:

  • Quantify previously unstudied processes in the Everglades such as rates of movement of fine suspended particulate matter and rates of interception of that particulate matter by vegetation. Also quantify advective exchange between water and solutes in the flowing surface water and shallow subsurface flow paths through peat porewater (these flow paths lead to increased residence times and reaction rates of dissolved constituents in the Everglades). The goal is to predict future effects of these processes on remobilization and downstream transport of phosphorus, in addition to determining the sensitivity of phosphorus remobilization/transport to the increased flows resulting from restoration.
  • Advise and guide the use of our experimental results in water-quality models. The purpose is to improve current estimates of the rate of remobilization and transport of phosphorus from the Water Conservation Areas, and to predict future rates of downstream transport into Everglades National Park under “restored” flows. This will be accomplished by generalizing our experimental results to improve the accuracy of the basin-scale water-quality and transport models (e.g. DMSTA, ELM, SICS, TIME) that are now being used (or will be in the future) to simulate Everglades water quality.
  • Relate the new knowledge gained from tracer experiments to ongoing investigations of the origin and maintenance of ridge and slough topography being conducted by SFWMD and universities.

Status: Active

Recent Products:

Harvey, J.W., Saiers, J.E., and Newlin, J.T., 2005, Solute Transport and Storage Mechanisms in Wetlands of the Everglades, South Florida. Water Resources Research, 41(5),W05009,doi10.1029/2004WR003507; Gaiser, E.E., Trexler, J.C., Richards, J.H., Childers, D.L., Lee, D., Edwards, A.L., Scinto, L.J., Jayachandran, K., Noe, G.B., Jones , R.D., 2005, Cascading ecological effects of low-level phosphorus enrichment in the Florida Everglades. Journal of Environmental Quality 34:717-723; 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 48:1993-2008; Harvey, J.W. and others, 2005, Surface-Water and Ground-Water Interactions in Water Conservation Area 2A, Central Everglades, USGS SIR 2004-5069.

Planned Products: Journal articles, white paper (about Arthur R. Marshall Loxahatchee NWR) fact sheets, data reports.

Specific Relevance to Information Needs Identified in DOI's Science Plan in Support of Ecosystem Restoration, Preservation, and Protection in South Florida (DOI's Everglades Science Plan) [Page numbers listed below are from the DOI's Everglades Science Plan. See Plan on SOFIA's Web site:]:

This study supports the following four projects in the DOI science plan: (1) Water Conservation Area 3 Decompartmentalization and Sheetflow Enhancement, (2) Arthur R. Marshall Loxahatchee NWR Internal Canal Structures, (3) Comprehensive Integrated Water Quality Feasibility Study, and (4) Landscape-Scale Modeling Study. Our study will determine the role of transport of fine particles in Everglades surface water in controlling storage, transport, and transformation of phosphorus (and other contaminants) in Everglades wetlands. The study will examine differences in fractional distribution of contaminants in various dissolved and solid forms throughout the Everglades, including size-distribution and chemical makeup of fine particles, transport rates of solutes and fine particles in flowing water, and rates of interception of fine particles by vegetation in addition to rates of solute exchange between surface water and peat porewater. These characteristics and processes will be measured in contrasting peat and marl forming wetlands, in adjacent ridge and slough, 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 River Slough and Taylor Slough in Everglades National Park. Interactions with hydrology will be addressed through field-tracer experimentation using carefully controlled injections to determine the fate of solutes and particulate matter under different flow conditions. These studies will provide a process-based characterization of a critical unknown; the role of suspended fine particle transport as a control on phosphorus cycling and ecosystem structure in the Everglades. The results of our investigations will be implemented in comprehensive water-quality models and landscape ecosystem models that are being used to adaptively guide the restoration. In particular, the results of these studies will be crucial in predicting the effects of WCA-3A Decompartmentalization Project (DOI Science Plan p. 66) and the Loxahatchee Internal Canal Structures Project (p. 39). This study will also provide key scientific data to the Comprehensive Integrated Water Quality Studies (p. 84) and Landscape-Scale Modeling Study (p. 81). The information that our project provides will help assure success in modeling transport characteristics of solutes and fine particles (including contaminants such as phosphorus), storage times, rates of remobilization of those constituents, and rates of downstream movement in what will become a hydrologically modified Everglades ecosystem under restoration. Finally, by quantifying and modeling particle transport in this system, this study will also benefit efforts to understand a previously unstudied part of the carbon cycle in the Everglades which influences development and maintenance of the Everglades ridge and slough landscape.

Key Findings:

  1. Developed reliable methods for quantifying surface water and ground water interactions throughout the vast interior wetlands of the Everglades (Choi and Harvey, 2000; Harvey and others, 2002; Krest and Harvey, 2003; Harvey and others, 2004a; Harvey and others, 2004b).
  2. Quantified the effect of surface water and ground water interactions on the mercury budget of the Everglades Nutrient Removal (ENR) project, the prototype for the Stormwater Treatment Areas (STAs) (Harvey and others, 2002).
  3. Conducted a successful proof-of-concept experiment to determine rates of transport of solutes and fine suspended particulates in the Everglades. Solute and fine-particle tracers were injected into surface water in Everglades National Park and their downstream movement carefully monitored. Those experiments showed that it will be possible to quantify two previously unrecognized storage processes for contaminants in the Everglades, i.e. (1) advective solute exchange (and associated phosphorus reactions) in flow pathways connecting surface water and shallow subsurface water in peat, and (2) interception of fine suspended particulates (and associated phosphorus) by vegetation. More tracer tests are needed in additional areas of the Everglades to validate our results, however, we expect that our results will provide become key input parameters for water quality models used to predict movement of phosphorus and other solute and particle-associated contaminants under restored flows in the Everglades (Harvey, Saiers, and Newlin, 2005; Saiers, Harvey and Mylon, 2003).
  4. Characterized particulate phosphorus concentrations across the Everglades. Particulate phosphorus was an important proportion of total phosphorus in the water column in WCA-1, WCA-2A, and Shark River Slough. Particulate phosphorus concentrations were also found to increase with long-term phosphorus enrichment. Most of the particles that held large amounts of phosphorus were small (0.45 - 2.7 µm) and likely were bacteria or CaCO3 particles (Noe and others, in preparation). We began a study of the temporal variation in particulate phosphorus concentrations and differences between ridge and slough in WCA-3A.
  5. Developed ecosystem phosphorus budgets for oligotrophic and enriched Everglades wetlands. Invasion of Typha in the Everglades results in a large increase in cycling of phosphorus from sediments to the water column as a result of macrophyte nutrient pumping (Noe and Childers, in review).

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