Melinda Wolfert Marc Stewart
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.
In recent years, this project focused on developing a groundwater component for the SICS model, an integrated model of Taylor Slough and northern Florida Bay. The SICS model is now calibrated, operational, and providing important insight into the flow and salinity patterns of the southern coastal Everglades. Hydrologic output from the SICS model is being used in development of ATLSS fish models. The next step with this groundwater project is to extend the methodologies developed as part of the SICS modeling effort to the much larger TIME model.
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Langevin, Christian D.
Langevin, Christian D.
Shoemaker, W. Barclay Guo, Weixing
The plans for installing the wells are as follows. One month prior to mobilization, all equipment, tools, and accessories will be purchased or tested and repaired. Approximately one week will be required to construct drilling platforms at the selected site and transport drilling equipment by airboat. The drilling equipment consists of a hydraulic engine that turns the drill stem, a tripod, air compressor, water pump, and miscellaneous hardware and drilling supplies. The deep monitoring well will be installed first to determine geology and locate permeable zones for remaining wells. We will attempt to install the deep well at a depth of approximately 150 feet, which is approximately the depth of the base of the Gray Limestone aquifer (Fish and Stewart, 1990). The remaining two wells will be installed at approximate depths of 75 and 20 feet. We anticipate that the well installation will take 6 to 8 weeks to complete.
The purpose of this task is to quantify the interaction of surface water and groundwater by deploying seepage meters 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. Therefore, the objective of this study is to directly measure seepage and map the thickness of the units that restrict vertical flow.
Traditional seepage meters are notorious for providing ambiguous data in low-flow settings. As part of this task, we will 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.
The purpose of this task is to collect 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 and plans for the installation of three additional wells. 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.
The first step in the continued development of the groundwater model is to update the aquifer characterization with the data collected during the installation of the deep well. This new information should significantly increase the 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 the seepage work. 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.
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1. Finalize and document the SICS integrated model
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, 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.
2. Development of the TIME groundwater model and coupling with the TIME surface water model
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 the seepage work. 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.
3. Continuous monitoring at groundwater wells and measurement of surface water/groundwater interactions
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. 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.
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U.S. Department of the Interior, U.S. Geological Survey, Center for
Coastal Geology
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