Project Summary Sheet

Project: Tides and Inflows in the Mangroves of the Everglades (TIME) Model Development

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

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

Funding (Source): USGS Place-Based Studies

Principal Investigator(s): Raymond W. Schaffranek (USGS/WRD), 703-648-5891, rws@usgs.gov; Harry L. Jenter (USGS/WRD), 703-648-5916, hjenter@usgs.gov; Kevin Kotun (NPS/ENP), 305-242-7829, Kevin_Kotun@nps.gov

Project Personnel: Michael P. Duff, 703-648-7151, mpduff@usgs.gov; 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; High Accuracy Elevation Data Collection, Desmond; Land Characteristics from Remote Sensing, Jones; Geophysical Mapping of Freshwater/Saltwater Interface, Fitterman; Evapotranspiration Measurements and Modeling, German; Groundwater-Surface Water Exchange Fluxes, Harvey; Freshwater Flows into Northeastern Florida Bay, Hittle; Vegetative Resistance to Flow, Jenter; Water Flows and Nutrient Fluxes to Southwest Coast of ENP, Patino; Across Trophic Level System Simulation, DeAngelis

Overview & Status: This project is focused on 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 two-dimensional Surface Water Integrated Flow and Transport (SWIFT2D) model is being coupled to SEAWAT, a variable-density ground water flow model based on the Modular Groundwater Flow (MODFLOW) model, for concurrent simulation of surface and sub-surface flow and salt transport. A multi-layered SEAWAT ground-water model of the Southern Inland and Coastal System (SICS) has been developed for integration with the SICS surface-water model. A numerical algorithm has been developed to synchronize SWIFT2D tidal-compatible time steps with SEAWAT stress periods. The algorithm has undergone successful testing in the coupled SICS model. A report documenting regression techniques developed to correlate gaged and un-gaged culverts for model use has been prepared. A semi-automated procedure has been developed to spatially and temporally interpolate and formulate culvert and structure flows along Tamiami Trial from SFWMD and TIME databases to drive numerical model simulations. Flow monitoring in the wetlands to evaluate forcing effects has continued and a paper documenting thermal convection-driven mixing processes has been submitted for scientific peer-reviewed publication. The SWIFT2D model formulation is currently being extended to incorporate wind-stress sheltering, vegetative-resistance correlation, and energy-dependent evapotranspiration. The partial land-surface elevation grid of the TIME model domain has been extended to include Lostsman’s Slough with the addition of topographic data made available on 4/5/02. The preliminary version of the TIME model grid has been extended to the Tamiami Trail and Florida Bay boundaries.

Needs & Products: A critical objective of the Everglades restoration effort is to preserve ecological conditions that are consistent with habitat requirements. This objective is particularly problematic in the transition zone between the wetlands and coastal embayments encompassing the mangrove ecotone where freshwater inflow effects on salt concentrations also must be considered. A Fact Sheet describing the TIME project has been prepared, posters describing the SICS and TIME models were presented at Florida Bay Science Conferences, and abstracts describing various aspects of the TIME project were presented at the 2000 Greater Everglades Ecosystem Restoration Science Conference. A session of papers on the TIME project has been prepared for presentation at the 2002 Second Federal Interagency Hydrologic Modeling Conference. A report documenting the TIME model development will be produced at the conclusion of the project.

Application to Everglades Restoration: 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 inflows, 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.