Project Summary Sheet

Study Title: Tides and Inflows in Mangrove Ecotone (TIME) Surface-Water Model Development
Study Start Date: October 1, 1999 Study End Date: September 30, 2005
Web Sites: TIME.er.usgs.gov
Location (Subregions, Counties, Park or Refuge): Total System Everglades National Park
Funding Source: USGS Priority Ecosystem Science (PES) Initiative
Principal Investigator(s): Raymond W. Schaffranek
Study Personnel: Ami L. Riscassi
Supporting Organizations: National Park Service, U.S. Army Corps of Engineers, South Florida Water Management District
Associated / Linked Studies: TIME Ground-Water Model Development

Overview & Objective(s): The objective of this study is to develop the surface-water component of the TIME model by incorporating hydrologic process-study findings in a hydrodynamic/transport model. The model provides the capability to analyze the effects of freshwater inflows on coastal marine ecosystems along the interface of the southern Everglades wetlands with the Gulf of Mexico and Florida Bay. Model development is being accomplished using coastal flow and salinity data coupled with measurements of wetland flow velocities and water levels. The study includes tasks focused on 1) monitoring wetland hydrologic processes and coastal dynamic forces, 2) translating processes and forcing mechanisms into empirical expressions and mathematical equations, 3) transforming these expressions and their correlations to ecosystem properties into numerical algorithms, 4) integrating process algorithms into a computer model framework, 5) tailoring the model to the Everglades wetlands and its coastal marine ecosystems, 6) calibrating the model using time series of water-level and flow data, and 7) documenting the model and any findings relevant to improved management of the Greater Everglades Ecosystem. The TIME model fills a void in the CERP design by providing a linkage for wetland and estuarine models being used to evaluate restoration scenarios.

Status: The TIME model has been extended to encompass the entire wetlands of ENP using the recently completed set of NMD topographic data. Precipitation and evapotranspiration data sets and processes have been developed and incorporated. Newly provided vertical datum adjustments have been applied to the model boundary-value data. The trial simulation period has been extended to four months and sensitivity tests on various empirical coefficients and numerical parameters have been conducted. The model appears to reasonably capture prominent flow features in the sloughs and wetlands of ENP.

Recent Products:
Two posters presented at USGS Surface Water and Hydroacoustics Workshops.

Abstracts submitted to National Conference on Ecosystem Restoration:

Schaffranek, R.W., and Riscassi, A.L., 2004, Sheet Flow Velocity in Everglades National Park, Florida.
Schaffranek, R.W., and Riscassi, A.L., 2004, Model for Simulation of Surface-Water Flow and Transport through Freshwater-Wetland and Coastal-Marine Ecosystems in Everglades National Park, Florida.

Planned Products: A summary report documenting the TIME surface-water model development is planned.

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) [See Plan on SOFIA's Web site: http://sofia.usgs.gov/publications/reports/doi-science-plan/]:

This study addresses fundamental restoration needs of Everglades National Park and Florida Bay projects to improve the quantity, quality, timing, and distribution of flow as identified and listed in the DOI Science Plan. The study supports the Combined Structural and Operational Plan (CSOP) project (p. 70) by providing a model to predict salinity in the mangrove community and northeast Florida Bay. The study provides input to the Florida Bay and Florida Keys Feasibility Study project (p. 76) on how restoration projects will alter the hydrology of Florida Bay. Flow velocity data collected in this study support the Water Conservation Area 3 Decompartmentalization and Sheet flow Enhancement (DECOMP) project (p. 66) by providing information on sheet flow conditions in key aquatic communities.

This study addresses Scientific Information Needs identified by the Science Subgroup (1996) as reported in the NRC assessment of the Critical Ecosystem Studies Initiative (CESI) “Science and the Greater Everglades Ecosystem Restoration” (2003) . The science needs include development of methods 1) to restore characteristic salinity and circulation patterns to estuaries, 2) to quantify water-management effects on salinities, water depths, and water flow in the mangrove zone, 3) to determine the acreage of favorable estuarine habitat, and 4) to restore the volume, timing, and distribution of freshwater flows to estuaries.

Key Findings:

1. External forces of precipitation, evapotranspiration, vegetative resistance, and winds cannot be ignored or misrepresented in models being used to test restoration scenarios.
2. Wet season sheet flow velocities in ENP typically range between 0.5 and 2.5 cm/s.
3. Diel thermal-driven stratification-de-stratification generates vertical mixing in the wetlands.