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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: 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 Greater Everglades Priority Ecosystems Science (GE PES) Initiative
Principal Investigator(s): Raymond W. Schaffranek
Study Personnel: Ami L. Riscassi, Daniel J. Nowacki
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 into a hydrodynamic/transport model. The TIME 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. This study includes tasks focused on 1) monitoring sheet flows, hydrologic processes, and coastal dynamic forces for model development and calibration, 2) formulating processes and forcing mechanisms into empirical expressions and mathematical equations, 3) transforming these formulations and correlations of processes to ecosystem properties into numerical algorithms, 4) integrating mathematical formulations into a computer model framework, 5) tailoring the model to represent the Everglades wetlands and coastal marine ecosystems, 6) calibrating the model using time series of water-level, flow, and salinity data, and 7) documenting the model and any findings relevant to providing insight into behavior of the Greater Everglades ecosystem. The TIME model fills a void in CERP by providing a linkage for regional wetland and estuarine models being used to evaluate restoration scenarios.

Status: The TIME surface-water model has been extended to encompass the entire wetlands of ENP. Precipitation, evapotranspiration, frictional-resistance, meteorological, and salinity data sets and hydrologic process formulations have been developed and incorporated into the model to simulate fresh and salt water mixing in the hydrodynamic transition zone connecting the freshwater wetlands of the Everglades with Florida Bay and the Gulf of Mexico. The original, provisional, development of the TIME surface-water model has undergone an extensive review and verification. Alternative grid interpolation methods have been evaluated to improve representation of land-surface properties and gradients within the model domain using all available topographic and bathymetric data. Vegetation class assignments for the 500-m grid have been modified to reflect sub-model-grid-scale heterogeneity at the 30.5-m Landsat resolution. This new vegetation technique has improved representation of the spatial variability of frictional-resistance and wind-stress effects in the model. Sensitivity tests on various boundary-condition treatments, empirical coefficient values, and numerical computational-control parameter assignments have been conducted. A comprehensive review of all data used to develop the model has been conducted. A field study of the effects of the Park Road (SR 9336) on sheet flow distribution between Taylor and Shark River Sloughs has been undertaken and is providing additional insight into improved representation of the road in the model. Efforts are underway to extend the model calibration and verification period to encompass an entire wet season. The model appears to reasonably capture prominent flow features in Taylor and Shark River Sloughs and adjacent coastal areas within ENP. Hydrologic data defining flow conditions and hydrologic process-study results in sloughs and coastal areas west of Shark River Slough are minimally sufficient to implement the model and insufficient to calibrate the model for the entire ENP domain. Future studies to alleviate these deficiencies should be considered. Techniques to animate simulation results have been developed and used to evaluate model performance. These computer animation techniques will greatly benefit use of the model to demonstrate ecosystem response to CERP management decisions and restoration efforts. All data collected within the TIME surface-water model development study have been entered into the SOFIA data base.

Recent Products:
Abstracts and posters presented at the First National Conference on Ecosystem Restoration, December 6-10, 2004, Lake Buena Vista, FL:

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.

Schaffranek, R.W. and Riscassi, A.L., 2004, Sheet Flow Velocity in Everglades National Park, Florida.

Presentation made at the American Institute of Hydrology 2004 Annual Conference: Integrated Water Resources Management, October 17-21, 2004, Las Vegas, NV:

Schaffranek, R.W. and Riscassi, A.L., 2004, Surface-Water Flow and Transport Model of the Southern Florida Everglades.

Reports published:

Schaffranek, R.W., and Riscassi, A.L., 2004, Flow Velocity, Water Temperature, and Conductivity at Selected Locations in Shark River Slough, Everglades National Park, Florida; July 1999 - July 2003, U.S. Geological Survey Data Series 110.

Schaffranek, R.W., 2004, Sheet-flow Velocities and Factors Affecting Sheet-flow Behavior of Importance to Restoration of the Florida Everglades, U.S. Geological Survey Fact Sheet 2004-3123, 4p.

Riscassi, A.L., and Schaffranek, R.W., 2004, Flow Velocity, Water Temperature, and Conductivity in Shark River Slough, Everglades National Park, Florida: June 2002-July 2003, U.S. Geological Survey Open File Report 04-1233.

Schaffranek, R.W., 2004, Simulation of Surface Water Integrated Flow and Transport in Two Dimensions: SWIFT2D User's Manual, U.S. Geological Survey Techniques and Methods Book 6, Chap. B-1.

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

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. The TIME model is capable of simulating fresh and salt water mixing in the hydrodynamic transition zone of the south Florida Everglades for the benefit of CERP.
  2. Measured wetland sheet flow velocities indicate that momentum lost by impounding water in WCAs is potentially a significant factor contributing to landscape changes.
  3. Diel thermal-driven stratification-de-stratification generates vertical mixing in Everglades wetlands and potentially contributes energy to biogeochemical processes of importance for consideration in restoration efforts.

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