U.S Geological Survey, South Florida Ecosystem Program: Place-Based Studies

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

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

Location: Central Everglades (including Florida Bay) & Southwest Coast/Big Cypress

Principal Investigator: Raymond Schaffranek (USGS/WRD), 703-648-5891, rws@usgs.gov, Harry L. Jenter (USGS/WRD), 703-648-5916, hjenter@usgs.gov, Eric D. Swain (USGS/WRD), 305-717-5825, edswain@usgs.gov, Christian D. Langevin (USGS/WRD), 305-717-5817, langevin@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

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

Associated Projects: Across Trophic Level System Simulation, (DeAngelis); 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 NE Florida Bay, (Hittle/ Patino); Vegetative Resistance to Flow, (Jenter/Schaffranek); Water Flows and Nutrient Fluxes to Southwest Coast of ENP, (Levesque); Land Margin Ecosystem Program, (Smith)

Overview & Status: This project, is focused on the translation of findings from hydrologic process studies and results of monitoring efforts from the Southern Inland and Coastal Systems (SICS) project toward the development of a model encompassing the entire saltwater-freshwater interface 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 explicitly coupled to the Modular Groundwater Flow (MODFLOW) model with SEAWAT interface for surface/ground-water solute transport simulation. Extension of the SICS model domain westward and direct coupling of the surface-water and ground-water models is intended to resolve boundary limitation problems and to remove operational constraints of the current SICS model implementation. Two workshops were held to identify hydrological needs of ongoing estuarine ecological species studies and to develop a comprehensive plans for TIME model design, support, and development. A website (http://time.er.usgs.gov) with a database repository for compilation of input data and sharing of model results has been constructed. Flow data for approximately 70 openings under Tamiami Trial (approximately 60 miles) have been compiled for water years 1987-1999. A numerical algorithm has been designed and developed to link the SWIFT2D model with the SEAWAT transport variant of MODFLOW and a MODFLOW grid and model component is under development for coupling to the SICS grid and mode. A flow monitoring station has been established near the wetland/tidal interface of Shark River to determine the feasibility of long term acoustic Doppler flow measurements in heavily vegetated areas. Initial ground-truthing of vegetation classifications determined from remote sensing imagery has begun. A preliminary and partial land-surface elevation grid of the TIME model domain has been generated from helicopter Aerial Height Finder (AHF) survey data.

Needs & Products: A critical objective of the south Florida ecosystem restoration effort is to preserve ecological conditions that are consistent with habitat requirements. This objective is particularly problematic in the transition zone between the Everglades wetlands and coastal embayments encompassing the mangrove ecotone where freshwater inflow effects on salt concentrations also must be considered. Articles will be prepared and submitted for publication in the technical Journals of appropriate professional societies as justified by significant findings and project progress. A Fact Sheet describing the TIME project is in preparation and numerous abstracts describing various aspects of project objectives have been prepared and submitted for presentation at the Greater Everglades Ecosystem Restoration Science Conference. A report documenting the model development will be produced at the conclusion of the project.

Application to Everglades Restoration: The TIME model will serve to address several key questions pertaining to restoration efforts, such as the response of coastal marine ecosystems such as the mangrove ecotonerently to inflow regulation, the likely concurrent changes in wetland hydroperiods and coastal salinities in response to various restoration scenarios, the external dynamic forcing factors, e.g., sea level rise, meteorological effects, etc., that could adversely affect regulatory plans and their likely significance, and key factors that influence salt concentrations in the estuarine mixing zone and how do they interact.