Project Summary Sheet

Project: Tides and Inflows in the Mangrove Ecotone (TIME) Model Development

Web Sites: http://time.er.usgs.gov/

Location (Subregion & County): Central Everglades (including Florida Bay) & Southwest Coast/Big Cypress - Dade, Collier, & Monroe Counties

Funding (Source): USGS Place-Based Studies Initiative

Principal Investigator(s): Raymond W. Schaffranek (USGS/WRD), 703-648-5891, rws@usgs.gov

Project Personnel: Ami L. Riscassi, 703-648-5877, ariscassi@usgs.gov

Supporting Organizations: U.S. Geological Survey, National Park Service/Everglades National Park

Associated / Linked Projects:

Groundwater Flow and Transport for the SICS and TIME Models, Langevin
Coupled Surface-Water/Ground-Water Model Development, Swain
High Accuracy Elevation Data Collection, Desmond
Land Characteristics from Remote Sensing, Jones
Evapotranspiration Measurements and Modeling, German
Water Flows and Nutrient Fluxes to Southwest Coast of ENP, Patino

Overview & Objective(s): This project is focused on the development of a model to simulate the interaction of tides, sheet flow, and aquifer leakage in the freshwater-saltwater mixing zone along the southwest Gulf coast and Florida Bay boundaries of Everglades National Park. The overall objectives of the project are to develop a model capable of simulating freshwater/saltwater mixing in the coastal mangrove ecotone, to implement a model of the Everglades National Park area at spatial resolution scales consistent with ecological model development and analyses, and to provide transport simulation capability to assess water quality conditions.

Status: The two-dimensional Surface Water Integrated Flow and Transport (SWIFT2D) model has been coupled to SEAWAT, a variable-density groundwater flow model based on the Modular Groundwater Flow (MODFLOW) model, for concurrent simulation of surface and sub-surface flow and salt transport. Flow monitoring in the wetlands to evaluate forcing effects and provide data for model calibration has continued. The SWIFT2D model formulation is currently being extended to incorporate spatial precipitation inputs, wind-stress sheltering, vegetative-resistance terms, and depth-dependent evapotranspiration. A land-surface elevation grid for the entire TIME model domain has been developed and a three-month simulation of the surface-water TIME model has been developed and tested.

Recent & Planned Products: Posters describing the TIME model development, flow-velocity monitoring in ENP wetlands, and fire effects on hydrology were presented at the 2003 Greater Everglades Ecosystem Restoration Conference. A session of papers on projects supporting the TIME project and a paper on the TIME model development were presented at the 2002 Federal Interagency Hydrologic Modeling Conference. Two reports documenting the flow-velocity data collected in the ENP wetlands during the 2000-1 and 2001-2 wet seasons have been produced. A report documenting the TIME model development will be produced.

Relevance to Everglades Restoration Information Needs: Development and use of the TIME model will serve to address restoration questions about how changes in inflow regulation will likely affect coastal marine ecosystems, what concurrent changes in salinities in land-margin ecosystems will result from modified freshwater deliveries, how external dynamic forcing factors, e.g., sea level rise, meteorological effects, etc., could adversely affect upland regulatory plans, and what dynamic factors influence salt concentrations in the estuarine mixing zone thereby affecting ecological habitat.

Key Findings:

• A three-month simulation of the TIME surface-water model has been found to capture the significant flow features of the Everglades wetlands interaction with adjacent dynamic coastal ecosystems.
• Flow velocities continuously monitored at strategic locations in the ENP wetlands indicate velocities are typically on the order of 0-3 cm/s.
• Monitoring and analyses of fire effects on wetland hydrology indicate that flow velocities are significantly increased in burned areas, but that residual effects may be short lived.