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U.S. Geological Survey Greater Everglades Science Initiative (Place-Based Studies)
Fiscal Year 2004 Project Work Plan
A. GENERAL INFORMATION:
Project Title: Groundwater Flow and Transport for the SICS and TIME Models
Other Investigator(s): Eric Swain, Melinda Wolfert, Marc Stewart, Peter Swarzenski (Geologic Division)
Project Summary: The interaction between surface water and groundwater can be a potentially significant component of the hydrologic water budget in the Everglades. The purpose of this project is to develop groundwater flow and transport models for the SICS and TIME hydrodynamic models. This work will be performed in close cooperation with those developing the surface water models (Eric Swain and Ray Schaffranek). The SICS model encompasses Taylor Slough and uses a 300-m grid resolution. The larger TIME model encompasses Shark and Taylor Sloughs and uses a 500-m grid resolution. A groundwater model has already been developed and linked with the SICS surface water model. This integrated SICS model simulates flows, stages, and salinities for the 5-year period from 1995 to 2000. Plans for the SICS model are to extend the simulation period through 2002 and complete a linkage to the South Florida Water Management District's model, called the "2x2" model. The SICS model will then be capable of performing detailed restoration scenarios for the Taylor Slough area. A preliminary groundwater model has also been developed for the TIME area, but this groundwater model has not yet been linked with a surface water model. Ray Schaffranek is currently finalizing a 3-month simulation with the TIME surface water model. As part of this project, the groundwater model will be linked with the TIME surface water model, and the simulation period will be extended to cover 2 years. A related CERP (Comprehensive Everglades Restoration Plan) project will extend this simulation period to 7 years and link with the 2x2 to perform Everglade restoration scenarios. This project also involves quantifying surface water and groundwater interactions by using nested monitoring wells and seepage meters. Data from the field studies are used to calibrate and verify the SICS and TIME models.
Project Objectives and Strategy: The objectives of this project for FY04 and FY05 are to: (1) finalize and document the integrated SICS model, which includes developing the methodology for linking the SICS model with the 2x2 model, (2) complete the ongoing study of wetland seepage rates, (3) synthesize existing hydrogeologic data and continue development of the TIME groundwater model, and (4) continue to collect continuous data at six groundwater monitoring wells.
Potential Impacts and Major Products: All of the numerical models currently used for CERP (Comprehensive Everglades Restoration Plan) neglect salinity and the effects of salinity on surface water and groundwater flow. The existing CERP models also fail to represent the hydrodynamic conditions in the coastal wetlands thereby limiting their ability to accurately simulate coastal flows. When coupled with the groundwater model developed as part of this project, the TIME and SICS models will be the only models capable of accurately simulating flows and salinities in the southern Everglades. This new capability will lead to better and more accurate biological models and will provide decision makers with reliable tools for managing the hydrologic system and evaluating alternative management scenarios.
Project personnel will participate in local Everglade conferences and present papers at selected national or international conferences. In addition to these conferences papers and abstracts, this project will result in the following major products:
Clients: ATLSS model developers, Everglades National Park, Big Cypress National Preserver, U.S. Army Corps of Engineers, South Florida Water Management District
B. WORK PLAN
Title of Task 1: Finalize and document the SICS integrated model
Task Summary and Objectives: Documentation for the SICS surface water model has been completed and is scheduled for publication by the end of FY03; however, documentation has not been prepared that describes the coupled model. For this task, documentation in the form of a journal article will be prepared to describe the methodology used to link the surface and groundwater models and to describe model results. This manuscript will be submitted to an international journal, such as Water Resources Research. For the numerical models developed as part of PBS to be useful for CERP, the models must be capable of simulating restoration scenarios. This task also includes development of the methodology for linking the SICS model with output from the 2x2. This linkage will allow restoration scenarios to be simulated with the SICS model. Model results will provide unique and detailed insight into the hydrologic effects of restoration on Taylor Slough.
Work to be undertaken during the proposal year and a description of the methods and procedures: Finalizing the SICS model requires a final comparison between field data and simulated model output. These comparisons and explanations of discrepancies will be described in the journal article. This task will also require that each hydrologic boundary in the SICS model is driven by output from the 2x2. The current SICS model contains several different types of boundaries: specified flows, specified stage, and specified groundwater head. Evaluating restoration alternatives becomes complicated because hydrologic boundaries, such as the C-111 canal, may function differently. The representation of boundaries in the SICS model will be documented in an Open-File Report.
Planned Outreach: Langevin and Swain have given presentations on the integrated SICS model at local, national, and international conferences and will continue to give papers at professional meetings. Langevin and Swain are also members of the CERP Model Refinement Team, and they routinely update the team with descriptions of the SICS model. This task will result in the publication of a journal article that describes the integrated SICS model. Plans to link with the 2x2 model have been discussed at CERP meetings. An Open-File Report describing the methodology for linking with the 2x2 is scheduled for publication in FY04.
Title of Task 2: Quantification of surface water and groundwater interactions
Task Summary and Objectives: The purpose of this task is to quantify the interaction of surface water and groundwater by deploying seepage meters, performing geochemical analyses, and mapping the thickness of peat and marl. Calibration of the SICS integrated model indicates that additional data are required to verify the simulated rates of leakage between surface water and groundwater. With the current version of the SICS model, there is no way to guarantee that the simulated interaction between surface water and groundwater, which can be significant during certain times, is accurate.
Work to be undertaken during the proposal year and a description of the methods and procedures: Traditional seepage meters are notorious for providing ambiguous data in low-flow settings. As part of this task, we will continue to use the latest technology, either heat-pulse, electromagnetic, or sonic methods, to develop a seepage meter for use in the Everglades. This new seepage meter will be deployed for a short time (approximately one week) at the nested groundwater monitoring wells constructed last year and at the new wells constructed as part of this work plan. This will allow us to "rate" the head differences measured in the wells to the flow measured by the meter. Once the rating is completed for each site, we are optimistic that the continuously measured heads in the wells will allow us to calculate continuous seepage rates. The meter will also be deployed for short times at other locations and at other times to determine the spatial and temporal variability in seepage rates. In addition to the seepage measurements, measurements of peat thickness will be made along airboat trails to develop a map of peat thickness. At several locations, closely spaced measurements also will be made to characterize the spatial variability in peat thickness. The peat thickness measurements will be used with the seepage information to characterize the hydraulic properties of the peat.
Planned Outreach: A description of the seepage work and map of the peat thickness will be posted on the TIME and Sofia websites. A complete presentation of the seepage and peat study will be presented in a final report of the TIME groundwater model in FY06.
Title of Task 3: Development of the TIME groundwater model and coupling with the TIME surface water model
Task Summary and Objectives: The purpose of this task is to continue with the development and calibration of the variable-density groundwater flow and solute transport model. The development of this model began in FY03 and a preliminary version of the model is running with the SEAWAT program. The objective of this task is to update and calibrate the current version of the groundwater model with existing field data and perform a 2-year simulation. Another objective of this task is to use output from the TIME surface water model to facilitate with the development and calibration of the groundwater model..
Work to be undertaken during the proposal year and a description of the methods and procedures: The first step in the continued development of the groundwater model is to update the model with new field data. This new information should significantly increase our ability to simulate groundwater flow in the southwestern part of Shark Slough. The next step is to update the representation of the peat layer in the model with the new data collected as part of Task 2. Once this data is incorporated into the model, traditional calibration procedures will be used to adjust model parameters until simulated values of water levels, salinities, and leakage match with observed values. The calibration procedure will focus on the accurate representation of leakage between surface water and groundwater. This will ensure that the TIME surface water model will contain an accurate groundwater component once the models are coupled.
Planned Outreach: Presentations on groundwater model development will be given at the GEERS conference, CERP meetings, and to interested parties. The coupled surface water and groundwater model will not be completed until 2005. In FY06, a WRI report will be published to document the model.
Title of Task 4: Continuous monitoring at groundwater wells and measurement of surface water/groundwater interactions
Task Summary and Objectives: The purpose of this task is to continue collecting continuous water level and salinity data at the monitoring wells installed as part of this project. There are currently six groundwater monitoring wells at three locations.
Work to be undertaken during the proposal year and a description of the methods and procedures: Instruments for measuring and logging continuous water levels and salinities are rented from HIF. Monthly or bimonthly visits by motor boat, airboat, or helicopter are required to download data and ensure data integrity.
Planned Outreach: Data collected from these wells is entered into ADAPS and made available to other agencies and interested parties.
C. BRIEF DESCRIPTION ON HOW PROJECT TASKS SUPPORT THE DOI AND USGS EVERGLADES RESTORATION SCIENCE PLANS
This project described in this work plan supports many of the hydrologic science objectives listed in the USGS Science Plan and also several of the specific water projects listed in the DOI Science Document. The purpose of this project is to improve the accuracy and predictive capabilities of the SICS and TIME models by including the process of surface water and groundwater interactions. The SICS and TIME models are designed to answer the following questions, which were selected directly from the USGS Science Plan:
Although not discussed here, the SICS and TIME also support, either directly or indirectly, many of the other science objectives listed in the plan.
The Florida Bay and Florida Keys Feasibility Study is listed as a specific project in the DOI Science Plan with science needs. The specific need is for models to simulate how restoration projects will alter the water elevation and salinity in coastal wetlands, lakes and streams. This is also a specific object of SICS and TIME. Consequently, the SICS and TIME models have been selected by CERP (USACE and the SFWMD) as the models to provide the important link between upland freshwater wetlands and Florida Bay.
U.S. Department of the Interior, U.S. Geological Survey
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Last updated: 04 September, 2013 @ 02:08 PM(HSH)