Hydrogeologic Characterization and Modeling of the

Hazlett-Kincaid, Inc. Specialized Geological Modeling Services

www.hazlett-kincaid.com

Hydrogeologic Characterization and Modeling of the Woodville Karst Plain, North Florida Report of Investigations: 2005 - 2006

January 18, 2007

Prepared for: Dr. Rodney DeHan Florida Geological Survey Gunter Building MS #720 903 W. Tennessee St. Tallahassee, FL 32304-7700

Reno, NV 775.337.8803

Dr. David Loper Geophysical Fluid Dynamics Institute Florida State University Tallahassee, Florida 32306-4360

www.hazlett-kincaid.com

Tallahassee, FL 850.386.1944

Report of Investigations: 2005 - 2006

Contributing Authors

Todd R. Kincaid, Ph.D. Vice-President / Geologic Modeler Hazlett-Kincaid, Inc. 27 Keystone Ave. Reno, NV 89503 (775) 337-8803

Gareth J. Davies, M.Sc. Groundwater Tracing Specialist Cambrian Ground Water Co. 109 Dixie Lane Oak Ridge, TN 37830 (865) 483-1148

Hazlett-Kincaid, Inc.

Timothy J. Hazlett, Ph.D. President / Hydrogeologic Modeler Hazlett-Kincaid, Inc. 6753 Thomasville Road Suite 108-213 Tallahassee, FL 32312 (850) 386-1944

Christopher L. Werner P.G. Karst Hydrogeologist Florida State University P.O. Box 3031 Tallahassee, FL 32315 (850) 591-2805

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TABLE OF CONTENTS Section

Page

1

Introduction ............................................................................................................................................. 1 1.1 General Scope of Work .................................................................................................................. 2 1.2 Project Team .................................................................................................................................. 2 1.3 Logistical Support and Funding ...................................................................................................... 2

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Hydrogeologic Setting & Water Resource Issues .................................................................................. 3 2.1 Woodville Karst Plain ...................................................................................................................... 3 2.2 Wakulla Cave System..................................................................................................................... 4 2.3 Water Quality Concerns ................................................................................................................. 5 2.4 Water Quantity Concerns ............................................................................................................... 6

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TASK-1: HOC DATABASE DEVELOPMENT ........................................................................................ 7 3.1 Initial Scope of Work ....................................................................................................................... 7 3.2 Project Status ................................................................................................................................. 7 3.2.1 Falmouth Meter Data 7 3.2.2 Data Portal 10 3.3 Recommended Actions ................................................................................................................ 12

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TASK-4: HYDROLOGIC DATA ANALYSIS ......................................................................................... 13 4.1 Purpose & Objectives ................................................................................................................... 13 4.1.1 Initial Scope of Work 13 4.1.2 Final Objectives 13 4.2 Modeling the Upper Confining Unit ............................................................................................... 13 4.3 Cave Maps & Tracer Pathways .................................................................................................... 15 4.4 Ames Sink Tracer Test Analysis ................................................................................................... 27 4.4.1 Inflows 27 4.4.2 Tracer Test Analysis 32 4.4.3 Spectrometer and IFF Comparison 42 4.4.4 Mass Recoveries 46 4.5 Aquifer Pumping Test Analysis ..................................................................................................... 52 4.6 Professional Presentations ........................................................................................................... 59 4.7 Recommended Actions ................................................................................................................ 60 4.7.1 Cave Mapping 60 4.7.2 Confining Unit Delineation 60 4.7.3 Tracer Testing 60 4.7.4 Aquifer Testing 60

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TASK-9: MULTIPLE TRACER STUDIES AT THE TALLAHASSEE SPRAY FIELD ............................ 62 5.1 Initial Scope of Work ..................................................................................................................... 62 5.2 Project Status ............................................................................................................................... 62 5.2.1 SESF Fluorescent Tracer Test Design 63 5.2.2 SESF Fluorescent Tracer Test – Interim Results 63 5.3 Plan of Action for Continuation of the Study ................................................................................. 65

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Task-3: WKP Hydrogeologic Modeling ................................................................................................. 71 6.1 Problem ........................................................................................................................................ 71 6.2 Purpose & Objectives ................................................................................................................... 71 6.3 Conceptualization and Model Design ........................................................................................... 71 6.3.1 Model Area & Boundary Conditions 71 6.3.2 Conceptualized Hydrogeologic Framework & Numerical Design 71 6.4 Results & Calibration .................................................................................................................... 72 6.4.1 Spring Fluxes 72 6.4.2 Heads 72 6.4.3 Conduit Velocities 73 6.5 Discussion .................................................................................................................................... 73 Hazlett-Kincaid, Inc.

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6.5.1 Model Successes 73 6.5.2 Efficacy of Numerical Modeling in Karst 74 6.6 Applications of the Model ............................................................................................................. 74 6.7 Model Limitations .......................................................................................................................... 74 6.8 Recommendations and Conclusions ............................................................................................ 75 6.9 Figures .......................................................................................................................................... 76 7

TASK-5: EDUCATION AND OUTREACH ............................................................................................ 84 7.1 Initial Scope of Work ..................................................................................................................... 84 7.2 Project Status ............................................................................................................................... 84 7.3 Recommended Actions ................................................................................................................ 85

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References ........................................................................................................................................... 86

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Appendices ........................................................................................................................................... 88 9.1 Appendix I: Compilation of Confining Unit Thickness Data 9.2 Appendix II: Confining Unit Thickness Contours UTM Zone 18 NAD83 Meters (Attached CDROM) 9.3 Appendix III: Stage Data for Ames Sink and Flow Data for Ames, Ames2, and Kelly Sinks (Attached CDROM). 9.4 Appendix IV: Tracer Recovery Data from the 2005 Ames Sink Tracer Test 9.5 Appendix V: Fluorescence Data Measured by the Indian Cave IFF During the 2005 Ames Sink Tracer Test (Attached CDROM). 9.6 Appendix VI: Governing Equations for the WKP Groundwater Flow Model 9.7 Appendix VII: Head Calibration Table 9.8 Appendix VIII: Karst Short Course - Woodville Karst Plain Field Guide

LIST OF FIGURES Section

Page

Figure 3-1. Example web pages from the Falmouth meter database website: (www.hazlett-kincaid.com/FGS/Meters). Top left: Main page providing a listing of all metered stations and access to all of the data and web content related to the Falmouth meter database. Top right: Station page for the B-Tunnel meter providing access to the five flow, temperature, and conductivity plots, the beginning and end dates for the data record, and access to a map of the station location and plot of the conduit cross-sectional area at that location. Bottom left: Flow directional analysis page providing a map of all meter locations and access to a rose plot (bottom right) for each meter showing the measured direction of flow and frequency of measurement at each meter where the measured directions are broken into five-degree bins about a 360-degree plot of azimuths. ................................ 8 Figure 3-2. Example web pages from the Falmouth meter database website: (www.hazlett-kincaid.com/FGS/Meters). Top left: Project overview providing a written description of purpose and scope of the metering project and access to a photo gallery (top right) and description of how the conduit cross-sections are measured (bottom left) to provide the necessary data to convert the velocities measured by the Falmouth meters to flows. Bottom right: Example of a web page showing the cross-sectional area at each of the meter stations. ............................. 9 Figure 3-3. Example web pages from the Falmouth meter database website: (www.hazlett-kincaid.com/FGS/Meters). Left: Web page providing a query interface to the Falmouth meter database allowing the user to view and obtain a CSV data file for one parameter at any number of the meter stations for all or any part of the period of record for the respective stations. Right: Web page providing a similar query interface allowing the user to select multiple parameters at any one station. Either query also allows the user to download and plot the data in either the raw (15-minute interval) format or as a daily average. ................................................................................... 10 Figure 3-4. Example web pages from the Data Portal website: (www.hazlett-kincaid.com/FGS/HydroPortal/). Top left: Project overview. Top right: Data listing page providing a list of all the identified data streams relevant to the WKP along with a brief description and the relevant location in the center frame and the title, link to the managing agency’s website where the data can be downloaded, and a more in-depth description of the selected dataset in the right frame. Bottom left: Web page providing an example of an interface that would allow the user to interact with various combinations of datasets once the Data Portal gains access to the actual data streams. Bottom right: Link to an interactive query for the Falmouth meter database as an example of how the interactive query would produce results for a user. ............................................................................................................... 11


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Report of Investigations: 2005 - 2006 Figure 4-1. Stratigraphic sequence used to define the thickness of the confining unit overlying the Floridan aquifer.. ........................................................................................................................................................................... 154 Figure 4-2. Map of the total thickness of the confining unit above the Floridan aquifer throughout the part of the Florida Panhandle that includes the Woodville Karst Plain. ................................................................................. 15 Figure 4-3. Karst and hydrologic features in the Woodville Karst Plain, Florida including the thickness of the upper confining layer and tracer-defined groundwater flow pathways. Location map shows the broader extent of the Florida Karst Belt where the Floridan aquifer is unconfined and karst features are most prevalent.. ................. 158 Figure 4-4. Map of the Leon and Chip’s Hole Cave Systems in the Woodville Karst Plain of North Florida compiled from survey data collected by the Woodville Karst Plain Project. ......................................................................... 19 Figure 4-5. Map of the Wakulla, Sally Ward, and Indian Caves and part of the Leon Sinks and Chips Hole Cave Systems in the Woodville Karst Plain of North Florida compiled from survey data collected by the Woodville Karst Plain Project................................................................................................................................................ 20 Figure 4-6. Map of the Natural Bridge Cave System in the Woodville Karst Plain of north Florida compiled from survey data collected by the Woodville Karst Plain Project. ............................................................................................ 21 Figure 4-7. Maps showing the locations where the Leon Sinks and Chip’s Hole Cave Systems cross major roads and highways in the Woodville Karst Plain, north Florida. Location coordinates and the relative confidence in the position are listed in Table 4-3. ............................................................................................................................ 23 Figure 4-8. Maps showing the locations where the Leon Sinks, Chip’s Hole, Indian, Sally Ward, and Wakulla Cave Systems cross major roads and highways in the Woodville Karst Plain, north Florida. Location coordinates and the relative confidence in the position are listed in Table 4-3. .............................................................................. 24 Figure 4-9. Maps showing the locations where Wakulla and Ferrel Caves cross major roads and highways in the Woodville Karst Plain, north Florida. Location coordinates and the relative confidence in the position are listed in Table 4-3. ............................................................................................................................................................. 25 Figure 4-10. Maps showing the locations where Natural Bridge Cave System crosses major roads and highways in the Woodville Karst Plain, north Florida. Location coordinates and the relative confidence in the position are listed in Table 4-3. ................................................................................................................................................ 26 Figure 4-11 Pictures of the channel through Munson Slough and Ames Sink at low and high water stages. .............. 28 Figure 4-12. Pictures of Ames2 and Kelly Sinks at low and high water stages. ........................................................... 29 Figure 4-13. Location of the three swallets in Ames Slough south of Tallahassee, Florida relative to the estimated boundary of water flowing through the slough during low, medium, and high water levels. ................................. 30 Figure 4-14. Water level measured in Ames Sink as reported by the Capitol Area Flood Warning Network (CAFWN), Leon County Florida relative to the approximate times when two higher swallets within Ames Slough became active. Letters mark time periods wherein the fluctuating rate of change in stage appears to be related to flow into and out of progressively higher basins and swallets. (A) Ames Sink began to fill. (B) Ames Sink filled and then overflowed into Ames Slough. (C) Water overflowed into progressively higher depressions and sinks within the slough. (D) Ames2 began receiving water but eventually overflowed. (E) Kelly Sink began receiving water. (F) All flow returns to Ames Sink. ......................................................................................................................... 30 Figure 4-15. Water level measured in Ames Sink over two flooding periods as reported by the Capitol Area Flood Warning Network (CAFWN), Leon County Florida relative to the approximate times when two higher swallets within Ames Slough became active. The first flooding event was caused by a large storm. The second event was caused by a water release from the Lake Munson Dam by Leon County. The differently shaped hydrographs indicate that local rainfall during the first hydrograph caused depressions and sinks within the slough to take more water and at different rates than during the flood wave that generated the second hydrograph. In both cases, the slough responded to the flood by filling Ames Sink first and then overflowing into the progressively higher swallets. .................................................................................................................................................... 31 Figure 4-16. Water level in Ames Sink over two flooding periods relative to rainfall at Ames Sink and three regional stations. Gauges 601 and 602 are in the Lake Munson / Ames Slough surface water basin. Gauge 803 is downgradient of Ames Sink. The left peak in the hydrograph was primarily generated by rainfall whereas the later peak was driven by a planned release from Lake Munson. .......................................................................... 31 Figure 4-17. Pictures of tracer injections at Ames and Kelly Sinks during the 2004 and 2005 Ames Sink groundwater tracer tests, Woodville Karst Plain, Florida. .......................................................................................................... 33


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Report of Investigations: 2005 - 2006 Figure 4-18. Map of part of the Woodville Karst Plain, north Florida showing the tracer injection locations, traced groundwater flow paths, and the locations of sampling stations marked by positive or negative detections pertaining to the 2004 and 2005 Ames Sink tracer tests. Note that the primary flow path was determined to connect Ames and Kelly Sinks to Indian Cave and then to Wakulla Spring. The Indian to Wakulla connection is inferred to be via the Leon Sinks Cave System and traced connection to Wakulla Cave because of the positive detection at Wakulla K-Tunnel. The inferred pathway between Wakulla D-Tunnel and Indian Cave rather than Sally Ward Cave was based on tracer travel times. The pathway to Wakulla B-Tunnel was marked by very low tracer concentrations, too low to record a tracer recovery curve. None of the injected tracers were detected at the St. Marks River Rise, Rhodes Springs, Newport Spring, or McBrides Slough during the sampling periods. . 34 Figure 4-19. Uranine recovery curves at Indian Spring (IS), Wakulla K-Tunnel (WK), Sally Ward Spring (SW), and the Wakulla Spring Vent (WV) for the 2004 (04) and 2005 (05) Ames Sink tracer tests. The position of the approximate peaks (roughly the highest part of each curve) correlate to within less than one day at Indian and Wakulla Springs. Few samples were obtained from Sally Ward during the 2004 test, however the small curve appears to mimic the rising limb of the 2005 recovery curve. The tailing edge of the IS05 curve was extrapolated using an exponential curve fitted to the tailing edge data. .................................................................................... 35 Figure 4-20. Tracer recovery curves recorded at the Indian Spring sampling station during the 2005 Ames Sink tracer test, Woodville Karst Plain Florida. Both the eosin and uranine injections occurred immediately prior to a flood in the respective swallets. The phloxine-B injections at Indian Cave coincidently occurred as the eosin tracer was beginning to pass the sampling station and presumably enter the same siphoning conduit. The eosin curve is broader and lower than the uranine curve. The breadth is attributed to higher flow rates into the swallet at the time of injection. The magnitude of the fluorescence would have been similarly affected but is attributed primarily to the fact that eosin is approximately 20 times less fluorescent than uranine. .................................................... 36 Figure 4-21. Tracer recovery curves recorded at the Indian, Wakulla K-Tunnel, and Wakulla-Vent sampling stations during the 2005 Ames Sink groundwater tracer test, Woodville Karst Plain, Florida. All of the plots are normalized to the maximum recorded fluorescence and plotted against the days past the relevant injection to facilitate comparison. Groundwater velocities were calculated from the peak arrival times and the distance between stations. Straight-line flow paths were assumed between all stations except Indian to Wakulla KTunnel, which was assumed to connect through the Leon Sinks Cave System. The uranine and eosin peaks are difficult to confidently define at K-Tunnel and the Vent stations because of the very low tracer concentrations detected. Eosin was particularly problematic because it becomes masked when the uranine becomes detectable. However, under background conditions, the eosin should plot beneath uranine therefore the eosin peak is most probably reflected by the maximum positive deviation between the eosin and uranine curves. ...... 37 Figure 4-22. Tracer recovery curves recorded at the Sally Ward sampling station during the 2005 Ames Sink groundwater tracer test, Woodville Karst Plain, Florida. The travel times for both the apparent peaks are approximately one day longer than the travel times recorded for the same tracers at the Wakulla Spring Vent. The slower travel times indicate that the Sally Ward pathway is less prominent than the pathway to Indian Cave and then to Wakulla Spring via K-Tunnel. ............................................................................................................ 38 Figure 4-23. Comparison of distance, travel time, and calculated groundwater velocity for variations or segments of the observed flow pats between Ames and Kelly Sinks and Wakulla Spring in the Woodville Karst Plain, north Florida. There is an apparent exponential increase in groundwater velocity as the tracer approaches Wakulla Spring, presumably because the conduits in the aquifer become larger and carry more water as they approach the spring discharge. ............................................................................................................................................ 38 Figure 4-24. Tracer recovery curve for uranine recorded at the Indian Spring sampling station during the 2005 Ames Sink tracer test, Woodville Karst Plain Florida relative to the hydrograph at Ames sink spanning the period of the test. The uranine was injected immediately prior to a flood in Ames Sink that overflowed into Kelly Sink from Ames Slough approximately 2 days after the injection. The uranine recovery curve contains two distinct peaks wherein the depression between the peaks approximately correlates in timing and duration to the duration of flow into Kelly Sink. We therefore interpret the depression as dilution in tracer concentration resulting from a short duration flood of tracer-free water into the combined Ames/Kelly – Indian flow path at about the time that the tracer mass was passing the junction between the Ames and Kelly components of the pathway. ................. 40 Figure 4-25. A) Diagrammatic model of the Ames/Kelly Sink to Indian Spring flow path and the probable hydraulic head configuration (dashed lines) associated with a constant flux of runoff into the Ames Sink swallet but no runoff into the Kelly Sink swallet. C1 and C2 denote the relative conveyance capacities of the Ames and Kelly sections of the flow path. B) Hypothetical tracer recovery curves (black lines) associated with independent injections into Kelly and Ames Sinks under the hydraulic conditions described for (A). The gray lines mark the influence of the C1:C2 contrast on the height and width of the Ames Sink recovery curve. C-E) The effect of a short duration flood of tracer-free water into Kelly Sink at various times relative to the transit of the tracer center of mass past the junction between the two flow paths. C) The flood into Kelly Sink occurs as the tracer center of


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Report of Investigations: 2005 - 2006 mass is entering the Kelly section of the flow path where the height of the depression in measured tracer concentration is controlled by the magnitude of the flux into Kelly Sink and the width is controlled by the duration. D) The flood into Kelly Sink occurs before the tracer center of mass enters the Kelly section of the flow path where the shape of the leading edge of the recovery curve (A, B, C) is controlled by the magnitude and duration of the flood into Kelly Sink. E) The flood into Kelly Sink occurs after the tracer center of mass enters the Kelly section of the flow path where the shape of the tailing edge of the recovery curve (A, B) is controlled by the magnitude and duration of the flood into Kelly Sink. ............................................................................................ 41 Figure 4-26. Fluorescence and turbidity measured by the insitu filter fluorometer (IFF) deployed at the Indian sampling station during the 2005 Ames Sink tracer test, Woodville Karst Plain Florida. The data shows a clear rise in the green fluorescence (a measure of uranine), that contains two distinct peaks at the top of the curve. The center of the two peaks was measured at approximately 17 days after the injection, which correlates to the arrival of the uranine peak measured by the spectrometer data (Figure 4-21) at the same station...................... 43 Figure 4-27. Comparison of the Spectrometer and IFF data measured in Indian Cave during the 2005 Ames Sink tracer test, Woodville Karst Plain, Florida. The IFF plot shows the green minus blue fluorescence filtered to remove all points that deviate from a 4-hour moving average by more than 1  calculated over the same section of data; and the 4-hour moving average of the resulting dataset. ........................................................................ 44 Figure 4-28. Spectrometer vs IFF data measured in Indian Cave during the 2005 Ames Sink tracer test, Woodville Karst Plain, Florida. Correlation coefficients are shown for the bulk curves, and the leading and tailing sections of the curves. Both the leading and tailing sections of the curves are almost identically correlated meaning that the deviation is restricted to the region around the peak where the twin peaks evident in the uranine data have been attenuated in the green minus blue fluorescence data. ............................................................................... 44 Figure 4-29. Fluorescence and turbidity relative to temperature measured by the insitu filter fluorometer (IFF) deployed at the Indian sampling station during the 2005 Ames Sink tracer test, Woodville Karst Plain Florida. The data shows a consistent negative correlation between (A) red fluorescence and temperature and B) turbidity and temperature. C) The correlation does not appear to hold for green and blue fluorescence. ......................... 45 Figure 4-30. Fluorescence relative to turbidity measured by the insitu filter fluorometer (IFF) deployed at the Indian sampling station during the 2005 Ames Sink tracer test, Woodville Karst Plain Florida. The data shows a positive correlation between red fluorescence and turbidity but no apparent correlation between green or red fluorescence and turbidity. ................................................................................................................................... 46 Figure 4-31. Calibration curves for uranine, eosin, and phloxine-B plotted from standards calculated in May 2005 during the Ames Sink tracer test, Woodville Karst Plain Florida. The slope for each trend is shown next to the respective line along with the correlation coefficient R2........................................................................................ 47 Figure 4-32. Uranine and eosin concentration recovery curves measured at the Indian sampling station during the 2005 Ames Sink tracer test, Woodville Karst Plain Florida showing the calculated percent of the injected tracers recovered at the station during the test. The uranine mass recovery incorporated an extrapolation of concentrations on the tailing edge of the curve to background levels based on an exponential curve fitted to the tailing edge of the recovery curve. The leading edge of the eosin curve was not measured due to a broken sampler. Both the leading edge of the uranine curve and the tailing edge of the eosin curve were masked by the presence of the other tracer in the water samples and thus concentrations were not calculated for those periods. The tailing edge of the eosin curve was not extrapolated because there were insufficient points on the tailing edge of the curve to yield a confident trend. Note that the phloxine-B was injected as the leading edge of the eosin curve was passing the sampling station indicating that the two tracers traveled nearly together downgradient. ............................................................................................................................................................... 48 Figure 4-33. Uranine, eosin, and phloxine-B concentration recovery curves measured at the Wakulla Spring Vent sampling station during the 2005 Ames Sink tracer test, Woodville Karst Plain Florida showing the calculated percent of the injected tracers recovered at the station during the test. The magnitude of the eosin curve is likely attenuated due to masking by both phloxine-B, which traveled simultaneously with the eosin, and uranine, which arrived slightly after the eosin but overlapped the recovery curve significantly. ................................................... 49 Figure 4-34. Uranine concentration recovery curves measured during the 2004 Leon Sinks – Wakulla tracer test, Woodville Karst Plain Florida showing the calculated mass recoveries and a plot of reduction in mass recovery vs. distance along the conduit flow path. Mass recoveries at Upper River Sink, Turner Sink, and Wakulla KTunnel and AK-Tunnel are based on an assumption of 100% recovery at Upper River Sink an assumption of constant flow between Upper River Sink and Wakulla K-Tunnel. The mass recovery calculated for the Wakulla Spring Vent is based on the average flow measured at that location during the testing period by the Falmouth hydraulic meter..................................................................................................................................................... 50


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Report of Investigations: 2005 - 2006 Figure 4-35. Map of part of the Woodville Karst Plain of north Florida showing the position of the pumping and monitoring wells relative to the conduits in the Wakulla Cave System and traced groundwater flow paths. ........ 53 Figure 4-36. (A) Plot of water level vs time in two pumping wells and one monitoring well during an aquifer pumping test conducted by J. Strickland in January 2005 for the Wakulla Water Bottling Company, Wakulla County Florida. Pumping for the aquifer test began at approximately 4140 minutes and lasted for approximately 1500 minutes, terminating at approximately 5640 minutes. This period is marked by approximately 3 ft of drawdown in the pumping wells and the pink square points in the monitoring well data. Strickland argued that there was no observable water level decline in the monitoring well due to the pumping, however, there is a noticeable depression in the trend of peak water levels during the pumping period. (B) Plot of water level vs time in the observation well compared to tide measured in Apalachicola Bay, Florida. Note the correlation between tide and the diurnal rise and fall of water levels in the observation well, which indicates a highly conductive connection between the aquifer at the well and the coastal discharges such as Spring Creek springs. ................................ 54 Figure 4-37. Plot of water level vs time in a monitoring well during an aquifer pumping test conducted by J. Strickland in January 2005 for the Wakulla Water Bottling Company, Wakulla County Florida compared to flow measured at Wakulla Spring (Vent Flow) and in B-Tunnel within Wakulla Cave (B-Tunnel Flow) during the same time period. Pink boxes mark the water levels measured during the pumping period. There are three probable hydraulic signals reflected in the data. 1) The oscillations evident in both the water level and Vent flow data are attributed to tide. The direct correlation indicates that the well is in excellent hydraulic connection with the spring, which is also supported by the close proximity of the well to conduits in Wakulla Cave. 2) Both the water level and flow data show a declining trend over most of the measurement period and then the beginning of an upward trend toward the end. These trends are marked by lines drawn on the plot through the data. A thin line connects the tidal peaks in the Vent flow data. A heavier line connects the related tidal peaks in the water level data. And, a trend line marks decreasing flow in B-Tunnel. 3) There is an apparent decline in water levels in the monitoring well during the pumping period, as indicated by the shaded triangle (A), which marks a deviation between the otherwise well-correlated trend in tidal generated peaks in both the water level and Vent flow data. .................. 55 Figure 4-38. Plot of water level vs time in a monitoring well during an aquifer pumping test conducted by J. Strickland in January 2005 for the Wakulla Water Bottling Company, Wakulla County Florida compared to flow measured at Wakulla B-Tunnel within Wakulla Cave (B-Tunnel Flow) during the same time period. Pink boxes mark the water levels measured during the pumping period. Though there is a somewhat diurnal signal in the B-Tunnel flow data, the peaks do not correlate to peaks in the water level data from the observation well but rather appear to be correlated to the troughs. The plot indicates that flow in B-Tunnel was not affected by pumping during the pumping test......................................................................................................................................................... 57 Figure 4-39. Plot of flow at the Wakulla Spring Vent and Wakulla B-Tunnel vs. water levels measured in an observation well during an aquifer pumping test conducted by J. Strickland in January 2005 for the Wakulla Water Bottling Company, Wakulla County Florida. There is a strong correlation between flow at the Wakulla Spring Vent and water level in the observation well but no apparent correlation between the water levels and flow in Wakulla B-Tunnel. ..................................................................................................................................... 58 Figure 5-1. Map showing the locations of injection and sampling points used in the 2006 SESF tracer study and the groundwater flow pathways confirmed from the tracer test results. ...................................................................... 66 Figure 5-2. Tracer recovery curve for sampling station: monitor well SJ-1................................................................... 67 Figure 5-3. Tracer recovery curve for sampling station: monitor well SJ-2................................................................... 67 Figure 5-4. IFF fluorescence curve for sampling station: monitor well SJ-2. ................................................................ 68 Figure 5-5. Tracer recovery curve for sampling station: monitor well SE-10. ............................................................... 68 Figure 5-6. Tracer recovery curve for sampling station: Wakulla B-Tunnel. ................................................................. 69 Figure 5-7. IFF fluorescence curve for sampling station: Wakulla B-Tunnel. ............................................................... 69 Figure 5-8. Groundwater levels measured in USGS wells SJ-1 and SJ-2 between November 2005 and August 2006. ............................................................................................................................................................................. 70 Figure 5-9. River stage measured at the USGS gauging station on the upper St. Marks River between January 2006 and December 2006............................................................................................................................................. 70 Figure 6-1. Constant head boundary conditions are in blue, whereas the boundary is no flow everywhere else. The model area is shown superimposed on the potentiometric surface map from Davis 1996 to show how the boundaries were derived. ..................................................................................................................................... 76 Figure 6-2. Potentiometric surface map for the WKP model. Note the cave systems and inferred conduits in black. . 77


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Report of Investigations: 2005 - 2006 Figure 6-3. Detailed potentiometric surface map showing flow convergence on Leon Sinks, the SESF pathway, and Wakulla cave system. .......................................................................................................................................... 78 Figure 6-4. Detailed view of the potentiometric surface surrounding a hypothesized connection between the Wakulla cave system and Spring Creek. Lost Creek connects via the southernmost pathway coming in from the northwest.............................................................................................................................................................. 79 Figure 6-5. Detailed potentiometric surface showing construed conduit systems and their impact on heads in the upper reaches of the St. Mark’s and Wacissa systems. The Wacissa is shown on the right. .............................. 80 Figure 6-6. Average linear velocities are shown along the conduit pathways in the model of the basin. ..................... 81 Figure 6-7. Detailed average linear velocity magnitude map. ...................................................................................... 82 Figure 6-8. Detailed average linear velocity map of the upper St. Mark's and the Wacissa conduit systems. ............. 83


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1

INTRODUCTION Groundwater quality in the Floridan aquifer is degrading particularly due to non-point source pollution. Declines in spring water quality, clarity, and the health of the ecosystems that springs support are some of the more noticeable consequences. One reason for the persistent decline in groundwater quality is the fundamental failing of standard hydrogeologic methods in characterizing the predominantly karstic nature of the Floridan aquifer. This failing, which is primarily manifest in a drastic under-prediction of groundwater velocities and groundwater-surface water interactions has facilitated land-uses that have nearly immediate and deleterious impacts on groundwater and spring water quality. If these impacts are allowed to persist unchecked, or worse increase through continued lack of understanding, the result will very likely be further widespread and significant reductions in the quality of groundwater in the Floridan aquifer and the loss or significant decline in Florida’s spring water ecosystems. Degrading groundwater quality, the resulting impacts to springs and springsheds, and to a lesser extent, the failing of the hydrogeologic profession to adequately address these problems, have become increasingly recognized over the past 15 years by the water resources community particularly the Florida Department of Environmental Protection (FDEP) and the Florida Geological Survey (FGS). Stemming from the increased awareness of the problems, the FDEP organized the first formal conference dedicated to springs and springs protection issues (The Florida Springs Conference, 2000) in 2000. Another outgrowth of the problem was the formation of a non-profit organization of concerned hydrogeologic scientists and professionals (The Hydrogeology Consortium) whose aim is to improve our collective understanding of karstic controls on groundwater flow in the Floridan aquifer and promote and facilitate appropriate changes to aquifer characterization methodologies and regulations through focused applied research, and concerted public outreach and education. Hazlett-Kincaid, Inc. (HKI) joined the Hydrogeology Consortium (HC) in 2000 intent on applying knowledge gained through graduate research conducted by its principals to the groundwater and spring water problems in Florida. Through proposed research projects funded by the FGS and FDEP, HKI’s work has focused on: 1) defining and characterizing the influence of karst conduits on groundwater flow patterns and velocities, and groundwater / surface water interactions; 2) developing improved modeling techniques for simulating groundwater flow through extensively karstified aquifers; and 3) broadening the public understanding of karst groundwater problems through focused public education and outreach. In the pursuit of those goals, HKI entered into a contracting collaboration with the Florida State University in 2001 and began working jointly with the Geophysical Fluid Dynamics Institute (GFDI) on an ongoing research and outreach effort funded by the FGS Hydrogeology Program, the FDEP Springs Initiative Program, and the Florida Department of Natural Resources (FDNR) to characterize the hydrogeology and hydrology of a specific hydrologic basin and apply the knowledge gained from that endeavor to improving groundwater resource management throughout the karstic region of Florida. The intent is to develop improved conceptual and numerical models of groundwater flow a single karst basin, and a methodology for their development that can be applied to other such spring basins. Four factors contributed to the selection of the Woodville Karst Plain (WKP) of north Florida as the basin to characterize. 1) The WKP contains Wakulla Spring, which has experienced significant water quality declines in recent decades resulting in growing public recognition and concern. 2) The WKP is dominated by relatively few but large magnitude cave/spring/river systems that render the individual hydrologic basins and problems relatively easy to constrain and study. 3) Extensive knowledge of the underwater cave systems in the basin has been collected and, 4) a well organized group of underwater cave explorers and surveyors, the Woodville Karst Plain Project (WKPP), has established a long term and consistent program of cave exploration and survey in the basin and offered to assist in research projects through the instrumentation of underwater caves for various forms of sampling and the contribution of maps and observations of the cave passages. This report provides a synopsis of the specific tasks that HKI was funded to perform during the fiscal year (FY) 2005-2006 that contribute to the broader research and outreach effort in the WKP.


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1.1

GENERAL SCOPE OF WORK

For the FY 2005-2006, HKI proposed and was funded to perform the following tasks. A more indepth description of the scope of work for each task is provided in subsequent sections of this report that discuss the respective tasks. 1. Develop a web-based user interface to a database for hydrologic data in the WKP that HKI initiated development of in FY 2004-2005 (Hazlett-Kincaid, 2005). See Section 3. 2. Develop an in-depth analysis of hydrologic data that had been collected by HKI and the WKPP in previous aquifer characterization projects in the WKP. The primary objectives for this task included: 1) a rigorous delineation of the distribution and thickness of the confining unit overlying the Floridan aquifer; 2) updating the maps of underwater caves in the WKP and synthesizing them into geospatially projected GIS shapefiles and maps; 3) analyzing the groundwater tracing data collected for the 2004 and 2005 Ames Sink tracer tests with Cambrian Ground Water, Inc. (CGW); and 4) disseminating the results of the analyses and knowledge gleaned from the analyses in professional and public forums. See Section 4. 3. Coordinate and collaborate with the US Geological Survey (USGS) to develop and execute a series of progressively scaled tracer tests utilizing fluorescent dyes and bacteriophage as tracers to map groundwater flow patterns emanating from the City of Tallahassee’s SE Spray Field (SESF) and identify the points of discharge for that water and the travel time along the flow paths. See Section 5. 4. Expand and refine a steady-state groundwater flow model of the WKP that HKI developed in FY 2004-2005 (Hazlett-Kincaid, 2005) such that it specifically addresses the known or hypothesized karst conduit controls on groundwater flow through the basin and is calibrated to measured or estimated average discharges at Wakulla, Spring Creek, and Wacissa Springs and the St. Marks River Rise, and measured velocities along the karst flow paths. See Section 6. 5. Deliver a professional short course on karst with special focus on the WKP and related groundwater resource management issues, and revise and improve the materials for that course that HKI developed in FY 2004-2005 (Hazlett-Kincaid, 2005). See Section 7.

1.2

PROJECT TEAM

In order to most effectively accomplish the goals and objectives for the FY 2005-2006 scope of work, particularly Task-2 and Task-3 described above, HKI assembled the following project. Representatives of each component of the team are contributing authors on this report.

1.3



The SESF groundwater tracer test was designed and executed in collaboration with Gareth Davies of Cambrian Ground Water Company. He also contributed to the interpretation of the Ames Sink tracer test data.



Christopher Werner, P.G. and Mack Park of the FSU-GFDI managed and performed the bulk of the field sampling and equipment maintenance for the SESF tracer testing.



Alan Baker, P.G. provided technical review and guidance throughout the project.

LOGISTICAL SUPPORT AND FUNDING

Logistical support, for this year’s endeavors particularly the SESF tracer testing and Karst Short Course, was provided by the FGS, FDEP, USGS, City of Tallahassee, Wakulla Springs State Park, and the Northwest Florida Water Management District (NWFWMD). Funding for this year’s tasks was provided by the FGS Hydrogeology Program, FDEP Springs Initiative Program, FDNR, and the City of Tallahassee.


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2

HYDROGEOLOGIC SETTING & WATER RESOURCE ISSUES

2.1

WOODVILLE KARST PLAIN

An extensively karstified topographic lowland known as the Woodville Karst Plain (WKP) is part of a broader karst belt that extends around Florida’s Big Bend from Ochlockonee Bay to Tampa Bay. Within this belt, the Floridan aquifer is unconfined, and therefore more vulnerable to contamination, because the clay-rich geologic formations usually overlying the limestone formations in much of the rest of Florida have been eroded away. The WKP constitutes the northwestern section of this karst belt and has been defined from its western boundary in the Apalachicola Coastal Lowlands to the Steinhatchee River in the east (Scott et al., 2001). The WKP is gently sloping and extensively karstified topographic lowland that extends from just south of Tallahassee in the north to the Gulf of Mexico in the south (Hendry and Sproul, 1966). The WKP consists of a thin veneer of unconsolidated and undifferentiated Pleistocene quartz sand and shell beds overlying a thick sequence of relatively horizontal carbonate rocks that comprise the upper Floridan aquifer. Within the WKP, the karstification is intensified by surface water that flows from north of the region, where the aquifer is confined or partially confined by clay-rich sediments. These sediments are in the Hawthorn Formation and parts of the Torreya, Chipola, Tamiami, Jackson Bulff, and Miccosukee Formations. Surface water flows onto the exposed carbonate rocks creating numerous dolines, sinkholes, karst windows, sinking streams and springs (Lane, 1986). Recharge to the Floridan aquifer in the WKP occurs by: 1) sinking streams, 2) direct infiltration of precipitation through sinkholes, 3) infiltration through the variably thick sands and soils overlying the aquifer, and 4) groundwater flow into the WKP from the north. The Florida Department of Environmental Protection (FDEP) and Florida Geological Survey (FGS) are engaged in an effort to physically document all of the sinkholes and sinking streams within the WKP. To date, more than 400 sinkholes, ephemerally or perennially water filled, have been mapped in the northwestern quarter of the WKP by the FDEP. This suggests the presence of more than 1000 such features across the entire WKP. Of these 1000+ sinkholes, several are known to receive water, either perennially or ephemerally, from surface streams that drain upland regions, with flows ranging seasonally between 0.7 cfs to 3500 cfs. The five largest such streams are, in order of relative average flow: Lost Creek, Fisher Creek, Munson Slough, Black Creek and Jump Creek (see Figure 5-3). Discharge from the Floridan aquifer under the WKP is predominantly through springs in the southern part of the region and submarine springs in the Gulf of Mexico. Wakulla Spring, with an average discharge of 380 cfs, is the largest inland spring in the WKP and one of the five largest springs in Florida. Wakulla Spring is the headwater of the Wakulla River, which flows for approximately 10 miles southeast to the St. Marks River and then to the Gulf of Mexico. Seasonal discharge from Wakulla Spring ranges from 25 cfs to 1900 cfs (Scott et al., 2002). This is the largest range of discharge recorded for any spring in Florida (Rupert, 1988). The Spring Creek group, which includes at least 14 underwater vents along the coast of Apalachee Bay in the Gulf of Mexico is listed as the largest spring in Florida and also displays a large range in discharge at between 300 and 2000 cfs (Scott et al., 2002). The variation in discharge at Wakulla Spring correlates closely with local rainfall, where spring hydrographs indicate that discharge responds to local storms in less than two days (Rosenau et al., 1977). The regional recharge area for these springs has been estimated to cover 965 mi2, including parts of Leon, Wakulla, and Jefferson Counties and portions of five Georgia counties as far as 50 miles north of the Florida-Georgia border (Gerami, 1994; Davis, 1996). In addition to the sinkholes and sinking streams, cave divers of the Woodville Karst Plain Project (WKPP) have mapped numerous underwater caves that trend for more than 10 miles across the basin from north to south at depths ranging from 50 to 300 ft below the water table (Werner, 2001). The five largest mapped caves in the WKP, ordered by length of mapped conduits, are: Leon Sinks Cave system (>14.9 miles), Wakulla Cave (>10 miles), Chip’s Hole Cave (>4 miles), Indian Springs Cave (>2.2 miles), and Sally Ward Cave (>1.2 miles) – Figure 1. Conduit diameters within these caves range from less than 7 ft to greater than 100 ft and average approximately 30-50 ft (Kincaid, 1999; Werner, 2001).


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Within one to two days after heavy or sustained rainfall, tannin-stained water flushes into the largest conduits that comprise Wakulla Cave, turning the normally clear water a dark tea color and reducing visibility for cave divers. The rapid response time indicates that the caves constitute a highly integrated network of conduits that convey water from sinkholes in the northern and western part of the basin to Wakulla Spring and the Spring Creek Springs. Wakulla Spring is thought to capture the majority of the ground water flow through the northern part of the region (Rupert, 1988) where the water is conveyed to the spring by conduits in Wakulla Cave.

2.2

WAKULLA CAVE SYSTEM

Wakulla Cave is the second longest known cave in Florida and one of the largest in terms of conduit diameters. Exploration and survey of the conduits within Wakulla Cave began in the 1950’s with the work of FSU students Gary Salsman and Wally Jenkins who made penetrations of up to 1000 ft into the cave. The U.S. Deep Cave Diving Team conducted some additional exploration and survey dives in 1987 and published the first comprehensive map of the cave system in 1989 (Stone, 1989). Since that time, Wakulla Cave has been extensively explored and surveyed by the Woodville Karst Plain Project (WKPP) who continues to explore and survey new passages and support scientific research in the cave at the present time. The cave surveys conducted by these teams represent the best available data describing the length, trend, and morphology of the cave passages. Most of these surveys focused on measuring the trend, length, and depth of the cave passages with compass, knotted line, and depth gauge. Passage morphologies, in terms of width and height were typically estimated by the divers conducting the surveys and reported as notes in the survey logs. At numerous points in the cave, more detailed measurements of location and morphology have been collected with the use of cave radio transmitters, used to locate a particular point in the cave at the land surface, and hand-held sonar instruments used to measure the distance from a survey station to the adjacent cave walls. Wakulla Cave is comprised of a dendritic network of conduits that extend for more than 10.1 miles in the northeast, northwest, south and southwest directions from Wakulla Spring (see Figure 5-5). All of the conduits are saturated and trend at depths of predominantly between –245 ft and –280 ft below the water table. The longest conduit, labeled A-Tunnel and O-Tunnel by the explorers, trends south from the spring / cave entrance for over 3.7 miles. M-, P-, and Q-Tunnels are other large conduits that trend for >0.8 miles, >0.7 miles, and >0.6 miles respectively in south-southwest directions from the southern part of the cave system. B-Tunnel and D-Tunnel, measuring >1.1 miles and >0.2 miles respectively, are the two largest tunnels that trend north from Wakulla Spring. The conduits can be roughly characterized as long tubes wherein the diameter and depth of any tube is relatively consistent though larger chambers of varying geometries typically divide individual or adjoining tubes (Kincaid, 1999; Werner, 2001). Groundwater tracing and flow gauging within the conduits as well as observations from the cave explorers has shown that, under high flow conditions, the southern tunnels convey dark water from Fisher Creek, Black Creek, and Munson Slough to Wakulla Spring within ten to fourteen days of a precipitation event, whereas the northern tunnels convey clearer groundwater to the Spring (Macesich and Osmond, 1989; Kincaid et al., 2004; Kincaid et al., 2005; McKinlay, 2006). Scallop marks on the cave walls have been observed throughout the cave and indicate the persistence of large ground water flow velocities operating over extended periods of geologic time. Under baseflow (low flow) conditions, the cave explorers have reported southerly groundwater flow directions in the southern reaches of O-Tunnel, P-Tunnel, and Q-Tunnel. Together with the variability in water clarity and discharge at Wakulla Spring, these data and observations suggest that Wakulla Spring and Spring Creek Springs are discharge points from a connected conduit network. The southern conduits in Wakulla Cave function as an overflow valve, delivering water to Spring Creek Springs under low flow conditions and overflowing to Wakulla Spring at higher flow conditions (Werner, 1998; Kincaid, 1999). This hypothesis is further supported by a strong and rapid correlation between sharp tidal fluctuations driven by the passing of Hurricanes Ivan and Frances in 2004 and discharge at the Wakulla Spring vent (Loper et al., 2005a).


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2.3

WATER QUALITY CONCERNS

Springs discharge groundwater from a broad region of the surrounding aquifer. Within that region, recharge, from often multiple sources, merges together within the aquifer and flows to the spring. The spring discharge is a composite of the waters from these sources. The quality of the spring water should thus be considered as a proxy for the water quality within the spring’s capture zone in the aquifer. Understanding and mitigating the mechanisms for spring water quality degradation will therefore contribute greatly to protecting the broader groundwater resource. A ten-year decline in water quality at Wakulla Spring and the ecological health of the spring basin (Chelette et al., 2002) has focused considerable public and government attention and effort on protecting Wakulla Spring from further degradation. Part of this attention has focused on revising zoning ordinances, regulations on development and best management practices in an effort to minimize the potential impacts of development on the quality of water at Wakulla Spring. In this context, the most important aspects of protecting the spring should center on a determination of where and how water is recharged within the springshed and how a given development will likely impact the quality and mechanism of that recharge. The decline of water quality at Wakulla Spring can be separated into two basic categories: 1) increasing dark water resulting in decreased water clarity, and 2) increasing nitrate loading resulting in the explosive growth of algae in the basin and possibly exacerbating problems with hydrilla (Loper et al., 2005b). Groundwater tracing demonstrates that the sinking streams along the western and northern margins of the WKP are the sources of dark tannin-rich waters in the spring discharge (Kincaid et al., 2005). It follows therefore, that developmental actions that create a change in the rate or quantity of runoff to these sinking streams will impact the quantity and timing of dark tannin-rich water flow to the spring, and thus the water clarity. Determining the source of the increased nitrate to Wakulla Spring has been a far more contentious issue than the water clarity concerns. The consensus of scientific opinion at present has identified septic systems and the City of Tallahassee’s wastewater spray field as the two predominant sources of nitrate in the spring discharge (Chelette et al., 2002; Loper et al., 2005b). Of those two sources, the City’s wastewater spray field has been identified as the primary source, though septic systems are considered a potentially more chronic problem (Loper et al., 2005b). The most rigorous effort aimed at establishing guidelines for protecting water quality at Wakulla Spring was convened as a public workshop in 2005 entitled “Solving Water Pollution Problems in the Wakulla Springshed of North Florida.” This workshop convened scientists, engineers, regulators, and other interested parties to present the most recent data describing the problems, debate the implications of those data for protection efforts, and to develop specific recommendations on how the government and public can most effectively endeavor to protect and restore water quality at Wakulla Spring (Hydrogeology Consortium, 2005; Loper et al., 2005b). Of those recommendations, the following guidelines summarize the recommendations from the workshop that we believe to be the most relevant to, and actionable by, private parties wishing to engage in development within the Wakulla Springshed of the WKP. 

Delineate zones of aquifer vulnerability as defined by rapid recharge at sinking streams or sinkholes connected to the Floridan aquifer by conduits (via active sinkholes) and minimize surface water runoff into such features.



Minimize the use of onsite waste disposal systems (septic systems) by using some form of centralized waste management system for all new developments whenever possible.



Use only EPA rated Level 4 or Level 5 onsite disposal systems that can achieve at least 70% nitrogen reduction, 95% reduction in BOD and TSS, and 98% reduction of fecal coliforms when centralized waste management systems cannot be used.



Protect high aquifer vulnerability zones through the use of conservation easements.



Reduce development density to 5 acres or more when centralized waste water systems cannot be used.


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

Make it a primary goal of all wastewater disposal activities in Leon and Wakulla Counties to reduce nutrient loading (nitrogen and phosphorus) to the aquifer.



Reduce and eliminate, if possible, the use of fertilizers within the Wakulla Springshed.



Engage in public education on the above recommendations for the long-term health of Wakulla Springs and its ecosystems.

To these, we also add that all hydrogeological characterizations performed to evaluate the potential impacts of proposed developments to Wakulla Spring or other springs in the karst belt of Florida specifically focus on the hydrologic relationship between the karst conduits that convey water to the springs and the surrounding surface water and groundwater environments.

2.4

WATER QUANTITY CONCERNS

In addition to the water quality and clarity problems, there is growing concern over potentially diminishing groundwater supplies and availability. The concept most central to this issue is that of the groundwater budget, which identifies the amount of groundwater available for use as the amount left in storage after outputs are subtracted from inputs. It is most often expressed by the following equation: Inputs = Outputs + Storage. The inputs are defined as all sources of recharge. Outputs are defined as all forms of discharge, and the change in storage can be thought of as the amount of groundwater available for use. If usage increases such that the total outputs exceed the total inputs, the change in storage will be negative, which means that the aquifer will be depleted. By contrast, as long as the total inputs equal or exceed the total outputs, there will be groundwater available for users. In the WKP, there are three major sources of recharge (Inputs): 1) water flow into the aquifer through sinkholes at the terminus of sinking streams; 2) infiltration from rainfall in the WKP; and 3) groundwater inflow to the WKP from northern regions. The main forms of discharge are: 1) natural discharge to springs, of which Wakulla and Spring Creek are the largest by far; 2) groundwater withdrawals from wells; and 3) seepage into the Gulf of Mexico. The relative magnitude of spring water discharge compared to seepage into the sea is currently a debated topic. However, regardless of the final determination on that subject and as the water budget equation demonstrates, groundwater pumping necessarily diminishes spring water discharge, seepage, or both. The question then becomes: to what degree can the springs and seepage be diminished without causing irreparable harm or undesirable changes in the natural systems that are dependent on spring discharge or seepage? Answering this question is the primary purpose of the State’s Minimum Flows and Levels (MFL) program, which is intended to establish the minimum amount of flow to key natural systems, such as Wakulla Spring and the Wakulla River, necessary to sustain a natural and healthy ecological system. In the ideal case, once the MFLs are established for the key natural discharges, the remaining groundwater can be safely used for human consumption and fairly divided amongst the various users. At present, the MFLs for Wakulla, Spring Creek, or the remaining springs in the WKP have not been established. However, in keeping with the MFL concept and in order to evaluate the impacts of groundwater withdrawal on Wakulla Spring, proposed groundwater withdrawals must be viewed in the context of all users in the spring catchment. Minimizing one use while disregarding others is not likely to have the desired protective effect on the quantity of spring water discharge. In addition, the fate of the water once it leaves the ground must also be considered in order to effectively evaluate the impacts to the water budget and thus flows to the springs. Groundwater that is pumped, used, cleaned, and then returned to the aquifer will have very little impact on spring flows compared to uses that transfer the water out of the basin.


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3

TASK-1: HOC DATABASE DEVELOPMENT

3.1

INITIAL SCOPE OF WORK

The purpose of this task was to develop an initial database and database interface to store and provide access to the burgeoning hydraulic datasets being collected and managed by the FGS WKPRG for the WKP. The overall goal was to establish a nucleus for the emerging Wakulla Springs Hydrologic Observatory / Water Data Center. There were two fundamental objectives. 1) Establish a database and/or data management system for the real-time hydraulic data being measured by the 7 Falmouth hydraulic meters that are currently deployed in Wakulla Cave and the one additional Falmouth meter that has been temporarily deployed in the Leon Sinks Save system and Indian Cave. 2) Develop a web portal to provide access to the Falmouth data and to all other streams of hydraulic data currently being collected in the WKP.

3.2

PROJECT STATUS

3.2.1 Falmouth Meter Data HKI developed a database and Internet interface for the storage and access to the Falmouth meter data in 2004/2005. The database was developed in MySQL and stored all of the real-time hydraulic data from the Falmouth meters that were initially installed in the WKP. In 2006, the database was updated to include data from the Falmouth meter temporarily installed in Indian Cave and to update the web interface for interactive queries. The database currently stores all the hydraulic data from all the Falmouth meters that have been deployed in the WKP. The database resides on an HKI LINUX server and is regularly backed up to independent onsite hard drives. Since 2004, HKI has maintained the database. The hydraulic data is delivered to HKI approximately once every 30-60 days via email as a set of ASCII text files structured in a standard format. HKI has written computer software that automatically uploads the ASCII files into the database, generates six sets of plots for each of the meter stations, and uploads the plots and data collection period to a website (www.hazlett-kincaid.com/FGS/Meters/). From this interface, any user can view the data plots, a map of the meter location, and a diagram showing the cross-sectional profile and area calculations for each of the meter stations. The six plot sets include: 1) a single-axis plot of flow for the period of record (measured velocity multiplied by the tabulated cross-sectional area for conduit at the respective meter location); 2) a dual-axis plot of temperature and conductivity for the period of record; 3) a dual-axis plot of flow and temperature for the period of record; 4) a dual-axis plot of flow and temperature for a two-week period prior to the most recent data point; 5) a dual-axis plot of flow and temperature for a one-month period prior to the most recent data point; and 6) a rose diagram showing the measured direction of flow plotted in five-degree increments and the relative frequency of measurements along each directional azimuth. In 2005, the website was updated to provide access to two interactive database queries which allow a user to select data over any range spanning the period of record for each meter as either: 1) any combination of two parameters for any one meter; or 2) one parameter for any combination of meters. The interface returns a plot of the selected data and a CSV file containing the selected data. The interface also allows the user to choose the raw data (15-minute interval) or a daily average of the data within the range selected. In 2006, the website interface was modified to correct problems with the plotting routines, specifically line thickness and color, and the date selection. The functionality was also extended to include the data from the Indian Cave meter. In addition to the modifications to the interactive interface, HKI corrected problems with the directional analysis interface such that the rose plots now provide a Hazlett-Kincaid, Inc.

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correct interpretation of the frequency of flow direction at the meters and corrected the cross-sectional area measurement with the latest data provided by the Woodville Karst Plain Project (Table 3-1). A written project overview, photo gallery of the meters and meter installation process, and a movie of the underwater installation of the B-Tunnel meter are also provided on the website. Figures 3-1, 3-2, and 3-3 provide examples of the web pages relevant to the web interface to the Falmouth meter database. Table 3-1 provides a summary of the data contained in the Falmouth meter database and the status of the Falmouth meters as of October 2006.

Figure 3-1. Example web pages from the Falmouth meter database website: (www.hazlett-kincaid.com/FGS/Meters). Top left: Main page providing a listing of all metered stations and access to all of the data and web content related to the Falmouth meter database. Top right: Station page for the B-Tunnel meter providing access to the five flow, temperature, and conductivity plots, the beginning and end dates for the data record, and access to a map of the station location and plot of the conduit cross-sectional area at that location. Bottom left: Flow directional analysis page providing a map of all meter locations and access to a rose plot (bottom right) for each meter showing


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the measured direction of flow and frequency of measurement at each meter where the measured directions are broken into five-degree bins about a 360-degree plot of azimuths.

Figure 3-2. Example web pages from the Falmouth meter database website: (www.hazlett-kincaid.com/FGS/Meters). Top left: Project overview providing a written description of purpose and scope of the metering project and access to a photo gallery (top right) and description of how the conduit cross-sections are measured (bottom left) to provide the necessary data to convert the velocities measured by the Falmouth meters to flows. Bottom right: Example of a web page showing the cross-sectional area at each of the meter stations.


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Figure 3-3. Example web pages from the Falmouth meter database website: (www.hazlett-kincaid.com/FGS/Meters). Left: Web page providing a query interface to the Falmouth meter database allowing the user to view and obtain a CSV data file for one parameter at any number of the meter stations for all or any part of the period of record for the respective stations. Right: Web page providing a similar query interface allowing the user to select multiple parameters at any one station. Either query also allows the user to download and plot the data in either the raw (15-minute interval) format or as a daily average. Table 3-1. Period of record and status as of Febriuary 2007 for the Falmouth hydraulic meters deployed in the Woodville Karst Plain, Florida and included in the Falmouth meter database constructed by HKI. Meter Station Wakulla Vent B-Tunnel C-Tunnel D-Tunnel AD-Tunnel K-Tunnel AK-Tunnel Turner Sink Indian Cave

Begin Date 10/29/03 11/22/03 11/25/06 2/7/04 2/7/04 2/7/04 2/7/04 12/7/03 6/4/05

End Date 8/10/06 10/5/06 10/5/06 10/5/06 9/27/04 10/5/06 10/5/06 1/2/04 10/8/05

XS Area (ft2) 741 129 886 504 2404 2700 3680 633 260

Status Off Line Working Working Working Working Working Working Removed Removed

3.2.2 Data Portal In 2006, HKI developed the Data Portal as a first step in increasing the access to and therefore the utility of all hydrologic data that is being collected and managed in the WKP. At present, the Data Portal provides access to the Falmouth meter database and provides a listing and description of other currently available data streams that have been identified by HKI as relevant to the WKP. In the latter case, it also provides a link to the managing agency's website where the data can be viewed or downloaded. The Portal database has been built using MySQL, and is served using PHP coded pages running through an Apache web server. The Data Portal website provides the following: 1) A main page with a brief description of the Data Portal and the project objectives; 2) A news page that will allow the database administrator to post relevant news about the Data Portal project such as brief descriptions of updates, or committee meeting dates and locations; 3) A list of all the partnering agencies contributing and participating in the Data Portal project;


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4) A listing and brief description of all the data streams that have been identified as relevant to the WKP along with links to the agency’s web page where the data can be viewed or downloaded; 5) An example of an interface to the Data Portal database from which the multiple data streams could be queried to produce graphical output and CSV files containing the data; and 6) A link to one of the Falmouth meter database queries that is also provided on the Falmouth meter database website, also as an example of the interactive capabilities that could be applied to the Data Portal. Figure 3-4 provides screen grabs showing the current layout of the Data Portal website (www.hazlettkincaid.com/FGS/HydroPortal/).

Figure 3-4. Example web pages from the Data Portal website: (www.hazlett-kincaid.com/FGS/HydroPortal/). Top left: Project overview. Top right: Data listing page providing a list of all the identified data streams relevant to the WKP along with a brief description and the relevant location in the center frame and the title, link to the managing agency’s website where the data can be downloaded, and a more in-depth description of the selected dataset in the right frame. Bottom left: Web page providing an example of an interface that would allow the user to interact with various combinations of datasets once the Data Portal gains access to the actual data streams. Bottom right: Link to an interactive query for the Falmouth meter database as an example of how the interactive query would produce results for a user.


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3.3

RECOMMENDED ACTIONS

The following recommendations have been compiled for the FGS and are intended to outline a course of action that will expand the existing database and web-based data portal to accommodate all of the data being collected in the WKP and facilitate interagency cooperation in the data portal project. 

Expand the existing Falmouth meter database to accommodate the data from the groundwater level loggers that have been installed throughout the WKP.



Develop a web interface for the groundwater level logger data.



Organize a stakeholder meeting to present the Data Portal concept to representatives from all of the agencies and organizations collecting and managing hydraulic data in the WKP and encourage their full participation in the program. The goals of this meeting should be: o

secure support for the Data Portal program from all agencies;

o

secure agreements from each agency on the use of and access to the data that they manage such that the data can be accessed and queried directly from the Data Portal website;

o

secure agreement on the design and layout of the Data Portal web pages particularly with respect to the project overview/objectives, database queries, and credits to the participating agencies;

o

identify the key personnel from each agency who will be responsible for developing the access protocols for their data; and

o

establish a timeline and milestones for the development and implementation of the Data Portal.



Organize an internal review process to guide the development of the Data Portal website particularly with respect to the design and layout of the project mission statement, database queries, graphical output, and usage instructions.



Establish a timeline and milestones for the development and implementation of the Data Portal database and website interface.


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4

TASK-4: HYDROLOGIC DATA ANALYSIS

4.1

PURPOSE & OBJECTIVES

4.1.1 Initial Scope of Work This task provided for the distillation, analysis and interpretation of hydrologic data generated by the Ames Sink and SESF tracer tests and Falmouth meter data collected by our project team, and other relevant hydrologic data such as that collected and managed by the Northwest Florida Water Management District (NWFWMD), Leon County Capitol Area Flood Warning Network (CAFWN), and the US Geological Survey (USGS). The purpose of the data analyses was to develop a more advanced and thorough correlation between the multiple data streams describing the hydrology of the WKP and thereby test and refine our conceptual, analytical, and numerical models and optimize future data collection and interpretation efforts. Anticipated deliverables included: 

Reports on the statistical data analyses including an identification of key data correlations, hydrographic analyses and tracer breakthrough curve analyses, maps, images, cross sections and GIS shape files describing hydrogeologic frame work and model calibration results.



A minimum of two (2) presentations by the research team at various seminars offered through the DEP, FSU or the Hydrogeology Consortium to share the findings with fellow scientists and resource managers.

4.1.2 Final Objectives HKI focused our efforts for this task on six lines of work: 1) geologic modeling of the thickness of the confining unit over the Floridan aquifer in the WKP; 2) updating the maps of the Leon, Wakulla, and Natural Bridge cave systems to reflect new survey data collected by the Woodville Karst Plain Project (WKPP) and synthesis of the cave maps and tracer test pathways into a GIS; 3) analysis of the data collected in 2005 for the second Ames Sink tracer test; 4) analysis of aquifer pumping test data collected by the Wakulla Springs Water Bottling Company relative to spring flow data collected by the Falmouth meters in Wakulla Cave and tide at Apalachicola Bay; and 5) presentation of tracer test results at professional meetings, seminars, and for FLDEP project management.

4.2

MODELING THE UPPER CONFINING UNIT

The thickness and position of the confining unit overlying the Florida aquifer is one of the most important variables controlling aquifer vulnerability because of its influence on aquifer recharge. As such, an accurate delineation of the confining unit is critical to the effective mapping of both aquifer vulnerability and recharge for modeling purposes. As of 2006, no adequate map of the distribution and thickness of the confining unit was readily available. In the absence of such a map, an accepted rule of thumb was to use the position of the Cody Scarp (Puri and Vernon, 1964; White, 1970; Crane, 1986) as the demarcation between confined and unconfined regions of the Floridan aquifer. That approach was based on the observation that, in north central Florida particularly Alachua and Columbia Counties, the position of the Cody Scarp coincides fairly well with the boundary of the Hawthorn Formation (Ceryak, 1981), which in that region constitutes the confining unit over the Floridan aquifer. A critical examination of the basis for defining the Cody Scarp, however, reveals that, while the correlation holds in some regions of Florida, it is unlikely that it holds everywhere because the scarp was defined purely on a topographic basis rather than on geologic or hydrogeologic conditions. An excerpt from White (1970) illustrates the problematic nature of the definition. “The [Cody] scarp is the most persistent topographic break in the State. Its continuity is unbroken save by the valleys of major streams, but its definition is variable. In many places it can be delineated with unequivocal sharpness; in others it is shown only by a gradual reduction of average elevation and a general flattening of terrain as the lower elevations are reached.” In the WKP, the correlation is particularly weak because there are numerous places north of the scarp, theoretically in the confined region of the aquifer, where rapid recharge to the Floridan aquifer occurs


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at swallets that receive considerable stream flow. Furthermore, field surveys in those areas confirm that the clays comprising the confining unit are not present or are very thin in many of those swallets and in some cases for some distance along the stream reaches. As a consequence of those observations, HKI endeavored with this task to construct an isopach map for the thickness of the confining unit using borehole data describing the depth to geologic units comprising the confining layer. The data for this endeavor was obtained from the FGS lithologic database for Gadsden, Leon, Jefferson, Liberty, Madison, Taylor, and Wakulla Counties (Scott et al., 2001) and the FGS Geologic Map of the Florida Panhandle (Scott et. al, 2001). The two datasets describe the depth to the top of all named geologic formations encountered in the boreholes, depth to the top of briefly described lithologic zones in the upper undifferentiated material, and the spatial orientation of geologic contacts that could be used to set a limit on the zero-thickness contour. Unit thicknesses were calculated by subtracting the depth to the top of the next lower unit or zone from the depth to the top of the unit in question. A total thickness was then computed by summing the thickness of all units encountered in the boreholes thought to be included in the confining layer, which in this region Figure 4-1. Stratigraphic sequence includes: all lithologic zones within the undifferentiated material used to define the thickness of the described as “clay” and/or “sand in clay matrix,” Citronelle or confining unit overlying the Miccosukee Formations, Jackson Bluff Formation, Tamiami Floridan aquifer. Formation, Hawthorn Group, and the Torreya or Arcadia Formations. Figure 4-1 shows the stratigraphic relationship between the units considered to be included in the confining layer. A compilation of the thickness data is provided in Appendix I. The thickness data was gridded using the EarthVision™ geologic modeling software. The isopach version of the 2D minimum tension gridding algorithm (Belcher and Paradis, 1992; Paradis and Belcher, 1990) was used to produce an isopach map (map of non-stratigraphically perpendicular unit thicknesses). The procedure interpolates the values onto a regularly spaced orthogonal grid from a set of spatially distributed data points where zero values are not contoured explicitly and minimum thicknesses are accommodated with the use of negative values (i.e. –10 indicates a minimum thickness of 10). Interpreted data was added to further constrain the gridding. These points included zero-thickness values assigned to all known swallets and minimum thicknesses assigned to the lower parts of stream reaches above the approximate zero-thickness contour derived from the geologic map. Figure 4-2 provides a map of the total thickness of the confining unit throughout the part of the Florida panhandle encompassing the WKP and the position of boreholes, geologic contacts, and other features from which thickness data was obtained for the grid construction. Figure 4-3 incorporates the confining unit thickness onto a map of the WKP showing the orientation of other pertinent hydrologic features including mapped extent of underwater caves, approximate potentiometric surface of the Floridan aquifer, location of streams and swallets, springs, and tracer-defined groundwater flow pathways. Appendix II (attached CDROM) provides a data file containing the 0, 10, 25, and 50 foot contour lines for the confining unit thickness projected to UTM NAD83 Zone 17 (meters).


14


Figure 4-2. Map of the total thickness of the confining unit above the Floridan aquifer throughout the part of the Florida Panhandle that includes the Woodville Karst Plain.

4.3

CAVE MAPS & TRACER PATHWAYS

The WKPP conducted several exploration dives in 2005 and 2006 that added significantly to the mapped extent of the Chip’s Hole Cave, Leon Sinks Cave System (LSCS) and Wakulla Cave, and provided the first known survey data of the Natural Bridge Cave System (NBCS). In late 2005, they explored and surveyed Chip’s Hole Cave for 2,300 feet past the previous end of exploration to the southeast toward the southernmost conduit in the Leon Sinks Cave System. They reported that the conduit increased in diameter from approximately 15-20 feet, which typifies most of the cave, to more than 50 feet in diameter near the end of their exploration but could not find a continuation of the conduit. They returned in April 2006 to perform a more detailed survey of the distant reaches of the cave but could not find a continuation of the conduit. They reported relatively high velocity flow to the southeast through the smaller diameter part of the cave that diminished to imperceptible levels in the larger diameter section near the southeastern end. In 2006, the WKPP extended the map of the LSCS by over 11,000 feet to the southeast from the southern extent of previous exploration and mapping. They reported that the conduit along that reach averaged more than 60 feet in diameter where the water depth at the ceiling of the conduit averaged 280 feet below the water table surface. The divers reported that the conduit appears to continue along the same direction and at similar size and depth beyond the end of their current exploration. The conduit is trending directly toward the westernmost conduit in Wakulla Cave north of Cherokee Sink. They also explored two new tunnels in Wakulla Cave, and collected survey data to tie a previously explored but not surveyed conduit into the cave map. One of the newly explored conduits (Q-Tunnel) extends to the south-southwest for approximately 3,000 feet from a point about midway along the P-


15


Tunnel conduit. The other conduit (PL-Tunnel) makes a smaller loop to the west off of the northern end of P-Tunnel. The divers reported that Q-Tunnel averages about 50 feet in diameter and 260 feet below the water table surface and that the conduit appears to continue in a similar direction and at similar size and depth past the end of their current exploration. PL-Tunnel is a loop tunnel that travels about 2,000 feet to the north, west, and south and then reconnects to P-Tunnel about 600 feet south of where it began. It was reported to be significantly larger in diameter, as much as 100 feet in places, and contain a small side conduit that connects to the bottom of an apparent well-developed sinkhole collapse feature. In their survey of the previously explored conduit, described as the “western bypass to O-Tunnel,” the divers were able to mark the position of radiolocation beacons that had been installed by the 1999 Wakulla 2 Project. Those locations along with the published coordinates for the beacons will allow for significant improvement to the map of Wakulla Cave. Finally, a new relationship with the property owner at Natural Bridge, and low water levels and relatively clear water at the St. Marks River Rise afforded the WKPP the rare opportunity to enter and explore the NBCS. They conducted several dives between June and August of 2006 that represented the first documented exploration of the cave system. Their survey data indicates that the NBCS is comprised of a dendritic network of conduits that extend from the St. Marks River Rise to each of the karst windows on the Natural Bridge property and then beyond to the north, northeast, and northwest. They surveyed a total of 12,108 ft of underwater cave passages making the NBCS the fourth-largest cave system in the WKP. They reported that the conduits trend at a depth of predominately 70 to 110 feet below the water table surface, flow through the conduits is generally from north to south, and that conduit diameters ranged from 20-40 feet on average to 100 or more feet in some large chambers. RQ-Tunnel and NBR-Tunnel were reported to carry the clearest water. RQ-Tunnel trends to the northeast past Lahon Spring, which is presumably a secondary discharge of clear spring water. NBRTunnel trends to the northwest and west, where the western spur (NBR-4) is trending directly toward the Rhodes Springs located at the corner of Natural Bridge and Old Plank Roads. Where these spring tunnels merge with the remaining passages in the NBCS, the clear spring water mixes with the darker water that typifies most of the water flow through the cave. The remaining tunnels convey water from the two sinking points of the St. Marks River through the intervening karst windows to the St. Marks River Rise. The westernmost river sink (Natural Bridge Sink) connects to the northwestern karst window via the NBR3-Tunnel. The eastern river sink connects to the north-central karst window via NBS-Tunnel. From that same basin, NBJ-Tunnel trends northeast toward but was not physically connected to the surface water outflow of Natural Bridge Spring. The divers’ observations indicate that either the northern spur of the NBR-Tunnel (NBR-2) or, an as yet unfound tunnel, will continue to the north and eventually connect to the disappearing streams in the far northern reaches of the St. Marks River Basin. HKI worked with the WKPP throughout 2005 and 2006 to process the WKPP survey data into geospatially projected coordinates in a GIS and then to render 2D maps and 3D models of the cave systems. Radiolocation markers were used to correct the cave survey data to known locations wherever possible. The maps were corrected to accommodate all of the exploration, survey, and radiolocation information collected by the WKPP through October 2006. Their most recent dives wherein they surveyed the western by pass to O-Tunnel and marked the locations of the associated radiolocation beacons have not been included in the maps. In addition to the Wakulla, Leon, and Chip’s Hole data, HKI also synthesized all other available maps and survey data for underwater caves in the WKP and all of the tracer-defined groundwater flow pathways into a compatible GIS. Table 4-1 provides a tabulation of total length of conduits for all of the known underwater caves in the WKP. Table 4-2 provides a breakdown of individual conduit lengths for Wakulla Cave. Figures 4-3 – 46 provide updated maps of the Chip’s Hole, Leon Sinks, Natural Bridge, and Wakulla Cave Systems. As another part of the cave mapping project, HKI provided URS Corporation, the engineering consultant for the Florida Department of Transportation, with coordinates for locations where the Leon Sinks, Chip’s Hole, and the Wakulla cave systems cross under major highways in the WKP. Those coordinates were tabulated from the 2005 version of the cave maps, which have since been updated with new survey data and corrected to GPS coordinates for known points in the caves wherever possible. Table 4-4 provides the coordinates for all major road crossings in the basin as they were Hazlett-Kincaid, Inc.

16


reported to URS Corporation in 2005 and as they are currently characterized using the more complete and accurate survey data. Maps showing the locations of the crossings as they are referenced in the table are provided in Figures 4-7 – 4-10. Table 4-1 Total length of explored and surveyed underwater caves in the Woodville Karst Plain. Cave System M Leon Sinks 24,003 Wakulla Springs 16,517 Chip's Hole 6,795 Natural Bridge 3,691 Indian Springs 3,626 Shepard's 1,734 Bird Sink 1,475 Little Dismal 905 McBride's 660 Church's 642 Sally Ward 529 Rat Sink 446 Hideaway 374 Hatchet 341 Spring Creek #2 247 Meetinghouse 234 Farrell Shallow 173 Ventana Azul 111 TOTAL 62,504


km 24.003 16.517 6.795 3.691 3.626 1.734 1.475 0.905 0.660 0.642 0.529 0.446 0.374 0.341 0.247 0.234 0.173 0.111 62.504

ft 78,750 54,189 22,292 12,108 11,897 5,689 4,839 2,968 2,166 2,108 1,737 1,463 1,228 1,120 810 769 566 363 205,063

mi 14.915 10.263 4.222 2.293 2.253 1.077 0.916 0.562 0.410 0.399 0.329 0.277 0.233 0.212 0.153 0.146 0.107 0.069 38.838

Table 4-2 Total length of explored and surveyed conduits in Wakulla Cave

Conduit O A B M P A2 Q K PL C MM D PC F C3 L C2 AT CS CR2 BB E J BC BA PLS CR1 Total Max Min

Length Length (m) (ft) 3,588 11,772 2,382 7,813 1,778 5,832 1,367 4,485 1,254 4,116 966 3,169 918 3,013 787 2,581 621 2,038 599 1,966 407 1,335 371 1,217 212 695 164 537 155 510 146 479 124 408 116 380 108 353 98 323 79 261 66 217 58 191 58 190 48 159 40 130 6 21 16,517 54,189 3,588 11,772 6 21

Ave Height (m) 4.0 5.9 1.7 3.1 7.5 1.5 8.5 7.5 7.6 1.8 1.4 2.1 1.0 1.1 1.8 2.4 1.4 5.2 0.8 1.0 0.8 1.2 5.0 0.8 0.9 7.6 1.4

Ave Height (ft) 13 20 6 10 25 5 28 25 25 6 5 7 3 4 6 8 5 17 3 3 3 4 17 3 3 25 5

Ave Width (m) 10.3 12.7 2.0 5.5 22.9 2.1 9.0 10.3 9.0 2.0 2.4 3.5 1.1 1.3 2.0 3.2 1.6 3.2 1.1 1.1 1.0 2.1 12.0 1.0 1.0 9.0 1.5

Ave Width (ft) 34 42 7 18 75 7 30 34 30 6 8 11 4 4 7 10 5 10 4 4 3 7 39 3 3 30 5

8.5 0.8

28 3

22.9 1.0

75 3

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Figure 4-3. Karst and hydrologic features in the Woodville Karst Plain, Florida including the thickness of the upper confining layer and tracer-defined groundwater flow pathways. Location map shows the broader extent of the Florida Karst Belt where the Floridan aquifer is unconfined and karst features are most prevalent.


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Figure 4-4. Map of the Leon and Chip’s Hole Cave Systems in the Woodville Karst Plain of North Florida compiled from survey data collected by the Woodville Karst Plain Project. Hazlett-Kincaid, Inc.

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Figure 4-5. Map of the Wakulla, Sally Ward, and Indian Caves and part of the Leon Sinks and Chips Hole Cave Systems in the Woodville Karst Plain of North Florida compiled from survey data collected by the Woodville Karst Plain Project. Hazlett-Kincaid, Inc.

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Figure 4-6. Map of the Natural Bridge Cave System in the Woodville Karst Plain of north Florida compiled from survey data collected by the Woodville Karst Plain Project. Hazlett-Kincaid, Inc.

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Table 5.3 Cave-Road crossing coordinates as reported to URS Corporation and the Florida Department of Transportation in 2005 and revised in 2006 with relative confidence in the position.

Notes:

Crossing ID URS Lat (DD) URS Lon (DD) REV Lat (DD) REV Lon (DD) Confidence CH-01 30.265344 -84.365331 30.265303 -84.365375 CH-01 CH-02 30.264884 -84.364682 30.265023 -84.364910 CH-02 CH-03 30.263525 -84.362201 30.264009 -84.362195 CH-03 CH-04 30.262479 -84.360804 30.262328 -84.360560 CH-04 CH-05 30.261707 -84.359648 30.261812 -84.359750 CH-05 CH-06 NR NR 30.261876 -84.353804 CH-06 CH-07 NR NR 30.260608 -84.352455 CH-07 CH-08 30.257530 -84.350930 30.258004 -84.353378 CH-08 LS-01 30.308602 -84.343926 30.308504 -84.343843 LS-01 LS-02 NR NR 30.297755 -84.352612 LS-02 LS-03 NR NR 30.297917 -84.351650 LS-03 LS-04 NR NR 30.295492 -84.349831 LS-04 LS-05 30.295321 -84.349999 30.295347 -84.349904 LS-05 LS-06 30.293861 -84.350432 30.293684 -84.350426 LS-06 LS-07 30.293149 -84.350684 30.292949 -84.350650 LS-07 LS-08 30.292603 -84.350766 30.292214 -84.350892 LS-08 LS-09 NR NR 30.276850 -84.341996 LS-09 LS-10 NR NR 30.276014 -84.340816 LS-10 LS-11 NR NR 30.273905 -84.338617 LS-11 LS-12 NR NR 30.272752 -84.337816 LS-12 LS-13 NR NR 30.272473 -84.338580 LS-13 LS-14 NR NR 30.272148 -84.335208 LS-14 LS-15 NR NR 30.269598 -84.336592 LS-15 LS-16 NR NR 30.269630 -84.335027 LS-16 LS-17 NR NR 30.266563 -84.338926 LS-17 LS-18 NR NR 30.266518 -84.339942 LS-18 LS-19 NR NR 30.266535 -84.340623 LS-19 LS-20 NR NR 30.258735 -84.339946 LS-20 LS-21 NR NR 30.256798 -84.338133 LS-21 LS-22 30.255430 -84.339360 30.254315 -84.334021 LS-22 LS-23 NR NR 30.247899 -84.329761 LS-23 LS-24 NR NR 30.245731 -84.328190 LS-24 LS-25 NR NR 30.244229 -84.328066 LS-25 IS-01 30.251750 -84.321456 30.251536 -84.321256 IS-01 IS-02 NR NR 30.250565 -84.319410 IS-02 IS-03 30.251278 -84.313045 30.250762 -84.312995 IS-03 NB-01 NR NR 30.285790 -84.155891 NB-01 NB-02 NR NR 30.285267 -84.154409 NB-02 NB-03 NR NR 30.284232 -84.151536 NB-03 NB-04 NR NR 30.284275 -84.150813 NB-04 FR-01 NR NR 30.274876 -84.312527 FR-01 SW-01 30.245565 -84.313033 30.245544 -84.313012 SW-01 SW-02 30.245060 -84.312980 30.245060 -84.312980 SW-02 SW-03 30.243824 -84.313768 30.243806 -84.313671 SW-03 SW-04 30.243603 -84.312743 30.243677 -84.312925 SW-04 SW-05 NR NR 30.243630 -84.312540 SW-05 SW-06 30.239532 -84.311565 30.239514 -84.311547 SW-06 WS-01 30.229955 -84.304407 30.230287 -84.304754 WS-01 WS-02 NR NR 30.212628 -84.304109 WS-02 WS-03 NR NR 30.208175 -84.312936 WS-03 WS-04 NR NR 30.205525 -84.312029 WS-04 NR: not reported URS: coordinates reported to URS Corporation and the Florida DOT in 2005 REV: coordinates determined from maps revised in 2006


Figure 4-7 4-7 4-7 4-7 4-7 4-7 4-7 4-7 4-7 4-7 4-7 4-7 4-7 4-7 4-7 4-7 4-7 4-7 4-7 4-7 4-7 4-7 4-7 4-7 4-7 4-7 4-7 4-8 4-8 4-8 4-8 4-8 4-8 4-8 4-8 4-8 4-10 4-10 4-10 4-10 4-9 4-8 4-8 4-8 4-8 4-8 4-8 4-8 4-9 4-9 4-9

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Figure 4-7. Maps showing the locations where the Leon Sinks and Chip’s Hole Cave Systems cross major roads and highways in the Woodville Karst Plain, north Florida. Location coordinates and the relative confidence in the position are listed in Table 4-3.


23


Figure 4-8. Maps showing the locations where the Leon Sinks, Chip’s Hole, Indian, Sally Ward, and Wakulla Cave Systems cross major roads and highways in the Woodville Karst Plain, north Florida. Location coordinates and the relative confidence in the position are listed in Table 4-3.


24


Figure 4-9. Maps showing the locations where Wakulla and Ferrel Caves cross major roads and highways in the Woodville Karst Plain, north Florida. Location coordinates and the relative confidence in the position are listed in Table 4-3.


25


Figure 4-10. Maps showing the locations where Natural Bridge Cave System crosses major roads and highways in the Woodville Karst Plain, north Florida. Location coordinates and the relative confidence in the position are listed in Table 4-3.


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4.4

AMES SINK TRACER TEST ANALYSIS

Ames Sink is a swallet that receives flow from Munson Slough, which in turn, receives approximately 60% of the surface water runoff from the City of Tallahassee. The water flowing into Ames Sink disappears into the Floridan aquifer where it poses a threat to water quality in the aquifer and any down-gradient springs. HKI and CGW proposed and carried out two groundwater tracer tests in 2004 and 2005 for the FGS and FDEP that were designed to determine where the water disappearing in Ames Sink discharges, measure the travel-time between insurgence and discharge, and characterize the hydraulics of the flow path(s) in the aquifer. Both tests were successful and definitively showed that the water from Ames Sink flows primarily to Indian Spring within approximately two weeks and to Wakulla Spring within approximately three weeks. Previous reports and publications (Hazlett-Kincaid, 2005; Kincaid et al, 2005) have described the design, execution, and results of each of the tests, and presented maps and discussions of the tracerdefined flow paths and travel times. As of 2006 however, an in depth analysis of the tracer recovery data had not been performed. The purpose of this task was therefore to develop such an analysis in comparison to available hydraulic data. Focus was directed on the 2005 tracer test because it was a broader test that addressed multiple flow paths and provided more complete tracer recovery curves at the sampling stations. 4.4.1 Inflows Water flow into Ames Slough is partially controlled by a dam at Lake Munson, which is operated by Leon County. At present, Lake Munson is a flood control reservoir wherein the County aims to regulate flow out of the lake, such that flooding in the downstream Ames Slough and surroundings is prevented or minimized. However, medium to large rain events tend to overwhelm Lake Munson’s storage capacity resulting in flood waves that travel from the dam through Munson Slough and Eight-mile Pond to Ames Slough and raise water levels at Ames Sink by several feet or more. Leon County and the NWFWMD operate a gauging station at Ames Sink to facilitate flood control through the balance of water levels in Lake Munson and Ames Slough. The station measures the water level in the sink and rainfall and is part of the CAFWN maintained by Leon County. HKI conducted a set of field surveys in the Ames Sink region in 2005 to search for other potential swallets within or bordering Ames Slough and document surface water flow patterns during and after storm events. The field surveys revealed that Ames Slough is a broad lowland comprised of numerous shallow basins, deeper depressions, and sinkholes. Two additional swallets were discovered: a small feature internal to the slough that was named Ames2, and a larger feature, named Kelly Sink located on the southeast side of the slough. Figure 4-3 shows the location of each of the swallets and the network of streams and channels that drain into Lake Munson and Ames Slough. Figures 4-11 and 412 provide pictures of the swallets and Munson Slough during high and low flow periods. The timing of both the tracer injections and the field surveys were coordinated with a storm event and with a water release from the Lake Munson Dam performed by Leon County such that inflows to each of the three swallets could be measured as Ames Slough flooded and drained. Discharge measurements were performed immediately upstream of Kelly and Ames2 Sinks as the slough flooded and overflowed the various internal depressions and sinks. The discharge into Ames and Kelly Sinks had also been measured during the 2004 tracer test. The intake capacity of each of the three swallets was constrained by recording the discharge into each swallet prior to overflow. Table 4-4 provides a listing of the discharge measurements and the estimated intake capacities for each of the swallets. Figure 4-13 shows the position of the three swallets relative to an estimated boundary of the water flowing into Ames Slough at low, medium, and high water levels. Figures 4-14, 4-15, and 4-16 provide hydrographs for Ames Sink and mark the timing of the swallet activations and their inflows.


27


Southern Munson Slough near Ames Sink looking north toward the bridge on Oak Ridge Road – dry period

Flow over the spillway on Lake Munson Dam into the upper Munson Slough following a large storm event

View to the northwest across Ames Sink during a low water period

View to the east looking into Ames Sink during a low water period

View to the east looking across Ames Sink during a high water period

View to the west looking across Ames Sink during a high water period

Figure 4-11 Pictures of the channel through Munson Slough and Ames Sink at low and high water stages.


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Water flow into Ames2 Sink during a rising stage in Ames Slough

High water level in Ames Slough at Ames2 Sink

Divers preparing to carry sampling tube into Kelly Sink at a low water level.

High water level in Kelly Sink with water flow entering the sink from left to right

Water flowing from right to left across Ranchero Road into Kelly Sink during a high water period

Rapid water flow into Kelly Sink during a high water period

Figure 4-12. Pictures of Ames2 and Kelly Sinks at low and high water stages.


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Table 4-4. Discharge and stage at the three swallets in Ames Slough during the 2004 and 2005 Ames Sink groundwater tracing experiments. Location

Date

Time

Flow (CFS)

Stage Condition

Ames

8/11/04

19:30

6.52

Rising

Kelly

8/23/04

17:50

64.25

Constant

Ames2

4/29/05

17:35

5.03

Constant

Kelly

4/30/05

9:00

0.00

Constant

Kelly

4/30/05

12:00

3.77

Rising

Kelly

4/30/05

18:45

15.39

Constant

Kelly

5/1/05

12:00

24.29

Constant

Kelly

5/2/05

10:58

0.00

Falling

Figure 4-13. Location of the three swallets in Ames Slough south of Tallahassee, Florida relative to the estimated boundary of water flowing through the slough during low, medium, and high water levels.

Figure 4-14. Water level measured in Ames Sink as reported by the Capitol Area Flood Warning Network (CAFWN), Leon County Florida relative to the approximate times when two higher swallets within Ames Slough became active. Letters mark time periods wherein the fluctuating rate of change in stage appears to be related to flow into and out of progressively higher basins and swallets. (A) Ames Sink began to fill. (B) Ames Sink filled and then overflowed into Ames Slough. (C) Water overflowed into progressively higher depressions and sinks within the slough. (D) Ames2 began receiving water but eventually overflowed. (E) Kelly Sink began receiving water. (F) All flow returns to Ames Sink. Hazlett-Kincaid, Inc.

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Figure 4-15. Water level measured in Ames Sink over two flooding periods as reported by the Capitol Area Flood Warning Network (CAFWN), Leon County Florida relative to the approximate times when two higher swallets within Ames Slough became active. The first flooding event was caused by a large storm. The second event was caused by a water release from the Lake Munson Dam by Leon County. The differently shaped hydrographs indicate that local rainfall during the first hydrograph caused depressions and sinks within the slough to take more water and at different rates than during the flood wave that generated the second hydrograph. In both cases, the slough responded to the flood by filling Ames Sink first and then overflowing into the progressively higher swallets.

Figure 4-16. Water level in Ames Sink over two flooding periods relative to rainfall at Ames Sink and three regional stations. Gauges 601 and 602 are in the Lake Munson / Ames Slough surface water basin. Gauge 803 is downgradient of Ames Sink. The left peak in the hydrograph was primarily generated by rainfall whereas the later peak was driven by a planned release from Lake Munson.


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The discharge measurements show that Ames Sink is not the primary insurgence in Ames Slough and therefore not the primary receptor of storm water runoff from the City of Tallahassee. The maximum inflow that Ames Sink can convey into the Floridan aquifer is less than 6.52 cfs because the stage in the sink was rising at the time that discharge was measured. Similarly, the inflow capacity at Ames2 Sink is probably close to 5 cfs, however the inflow capacity at Kelly Sink is greater than or equal to 64.25 cfs because the stage in the sink was holding constant when that discharge was measured. After observing how the three sinkholes become progressively activated as water flows into and overflows each sink, a closer inspection of the Ames Sink hydrograph reveals the cascading pattern of flow through Ames Slough. The fluctuating rate of change in stage at Ames Sink (Figure 4-14) is likely caused by flow into and out of progressively higher basins and sinks within Ames Slough. The pattern is not, however, identical between the two flood periods measured in 2005. Figures 4-15 and 4-16 show that the flood driven by a dam release at Lake Munson produced a significantly smoother leading edge to the hydrograph than the flood driven by a storm. The difference could be related to repeated rainfall events within the Ames watershed (Figure 4-16), however it could indicate that the controlled release caused water to move more quickly and directly through the slough to the progressively higher swallets. The locations of the rainfall gauges shown in Figure 4-16 are marked on Figure 4-3. The data used to construct the plots is provided electronically as Appendix III. In either case, these data clearly show that swallets identified during low flow periods may not be the primary insurgence points for disappearing stream flow during higher flow periods. The observation and documentation of overflow into progressively higher swallets in Ames Slough is consistent with observations made by this group in the Fisher Creek basin (Hazlett-Kincaid, 2004) and probably holds true for all of the sinking streams in the WKP. Furthermore, there might be additional smaller swallets within the slough and additional ones beyond the observed extent of the slough that are only activated during very high flow periods if Kelly Sink overflows. 4.4.2 Tracer Test Analysis The 2004 tracer test was conducted between August and September. Approximately 7.5 kg of Uranine (AY73) were injected into Ames Sink at the leading edge of a flood associated with Hurricane Bonnie. The 2005 tracer test was conducted between May and July and was broader in scope than the previous test. Three injections were performed: the first at Kelly Sink (approximately 12 kg Eosin – AR87), the second at Ames Sink (approximately 12 kg Uranine – AY73), and the third at Indian Spring (approximately 5 kg Phloxine-B – AR92). Both the Kelly Sink and Ames Sink injections were performed by releasing the dye directly into the stream flow as it entered the sink at the leading edge of a flood. The Indian Spring injection was conducted by having divers from the WKPP release the dye into a siphoning conduit approximately 500 ft into the cave (Figure 4-6) from the spring discharge after both of the floods had subsided. Figure 4-17 provides pictures of the three swallet injections. For both tests, regular sampling for the tracers was conducted at Wakulla, Sally Ward, Indian, and McBrides Springs and the St. Marks River Rise. During the 2004 test, several sinkholes located along the projected flow path between Ames and the down-gradient discharges were also sampled. During the 2005 test, K, D, and B-Tunnels in Wakulla Cave were sampled. In both tests, the strongest detection of the tracers injected at Ames and Kelly Sinks occurred at Indian Spring. The tracer(s) were also detected at all of the Wakulla stations as well as Sally Ward Spring. None of the tracers were recovered from the St. Marks River Rise, McBrides Spring, or the intermediate sinkholes. The tracer recovery data for the 2005 test is provided in Appendix IV. All four of the tracer tests were successful in that the injected tracers were detected at one or more of the sampling locations (Figure 4-18). Moreover, though the sampling period for the first test was not long enough to obtain complete recovery curves, those that were obtained compare favorably with the more complete curves obtained during the 2005 test (Figure 4-19). The favorable comparison indicates that the results adequately described the hydraulics (velocity and dispersion) of flow between the sinks and springs and that the flow hydraulics along the pathways were similar during both tests. Based on this comparison, we assume that a detailed analysis of the 2005 data will describe the hydraulics of flow along the traced paths under conditions similar to those encountered during the 2004 and 2005 tests – i.e. moderate rainfall occurring over short duration storms.


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Uranine dye flowing into Ames Sink – August 11, 2004

Uranine dye flowing into Ames Sink – August 11, 2004

Eosin dye being released into stream immediately above Kelly Sink – April 30, 2005

Eosin dye flowing into Kelly Sink – April 30, 2005

Uranine dye being gravity drained into Ames Sink during a rain storm – May 5, 2005

Uranine dye being gravity drained into Ames Sink during a rain storm – May 5, 2005

Figure 4-17. Pictures of tracer injections at Ames and Kelly Sinks during the 2004 and 2005 Ames Sink groundwater tracer tests, Woodville Karst Plain, Florida.


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Figure 4-18. Map of part of the Woodville Karst Plain, north Florida showing the tracer injection locations, traced groundwater flow paths, and the locations of sampling stations marked by positive or negative detections pertaining to the 2004 and 2005 Ames Sink tracer tests. Note that the primary flow path was determined to connect Ames and Kelly Sinks to Indian Cave and then to Wakulla Spring. The Indian to Wakulla connection is inferred to be via the Leon Sinks Cave System and traced connection to Wakulla Cave because of the positive detection at Wakulla K-Tunnel. The inferred pathway between Wakulla D-Tunnel and Indian Cave rather than Sally Ward Cave was based on tracer travel times. The pathway to Wakulla B-Tunnel was marked by very low tracer concentrations, too low to record a tracer recovery curve. None of the injected tracers were detected at the St. Marks River Rise, Rhodes Springs, Newport Spring, or McBrides Slough during the sampling periods.


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Figure 4-19. Uranine recovery curves at Indian Spring (IS), Wakulla K-Tunnel (WK), Sally Ward Spring (SW), and the Wakulla Spring Vent (WV) for the 2004 (04) and 2005 (05) Ames Sink tracer tests. The position of the approximate peaks (roughly the highest part of each curve) correlate to within less than one day at Indian and Wakulla Springs. Few samples were obtained from Sally Ward during the 2004 test, however the small curve appears to mimic the rising limb of the 2005 recovery curve. The tailing edge of the IS05 curve was extrapolated using an exponential curve fitted to the tailing edge data. An analysis of the recovery curves from Indian Spring provides for an evaluation of 1) the relative groundwater velocities along the pathways connecting Ames and Kelly Sinks to Indian Spring; 2) the hydraulic relationship between the two sinks; and 3) the relationship between data derived from laboratory analysis of water samples on a scanning spectrofluorophotometer (spectrometer) and fluorescence data measured by an insitu filter fluorometer (IFF), in this case deployed in a sealed container at the surface that received continuous flow from the sampling station. Relative Groundwater Velocities Figure 4-20 shows the eosin recovery curve from the Kelly Sink injection and the uranine recovery curve from the Ames Sink injection relative to the hydrograph at Ames Sink spanning the duration of the test and the timing of the three 2005 injections. Neither curve returns to the pre-injection fluorescence levels (thus they are incomplete) however both show significant portions of the tailing edge of the curve. The higher uranine fluorescence was expected because uranine is approximately 20 times more fluorescent than eosin and equal masses of the tracers were injected. The broader eosin curve is attributed to higher flow rates into Kelly Sink producing more dispersion. The eosin peak arrived at Indian Spring on May 14, 2005 or approximately 14 days after the injection. The uranine peak arrived at the same station on May 22, 2005 or approximately 17 days after the injection. The travel times equate to average groundwater velocities (assuming a straight-line path between injection and sampling locations) of approximately 2000 and 1600 ft/day (610 and 490 m/day) respectively (Table 4-4). The different velocities directly correlate with the respective intake capacities for each swallet, =64.25 cfs for Kelly Sink (Table 4-3). The recovery curves therefore demonstrate that the pathway between Kelly Sink and Indian Spring can be characterized by a larger diameter conduit(s) the pathway between Ames Sink and Indian Spring. Hazlett-Kincaid, Inc.

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Figure 4-20. Tracer recovery curves recorded at the Indian Spring sampling station during the 2005 Ames Sink tracer test, Woodville Karst Plain Florida. Both the eosin and uranine injections occurred immediately prior to a flood in the respective swallets. The phloxine-B injections at Indian Cave coincidently occurred as the eosin tracer was beginning to pass the sampling station and presumably enter the same siphoning conduit. The eosin curve is broader and lower than the uranine curve. The breadth is attributed to higher flow rates into the swallet at the time of injection. The magnitude of the fluorescence would have been similarly affected but is attributed primarily to the fact that eosin is approximately 20 times less fluorescent than uranine. Figures 4-21 and 4-22 show the tracer recovery curves at the Indian, Wakulla K-Tunnel, Wakulla-Vent, and Sally Ward sampling stations. All of the curves are plotted against the time past injection and are normalized to the maximum recorded fluorescence to facilitate a comparison of the travel times for the peak values. The plots indicate that there are at least two active pathways between Ames and Kelly Sinks and Wakulla Spring. The primary pathway connects to Indian Cave and from there to Wakulla Spring through the southern part of Wakulla Cave, most likely via the Leon Sinks Cave System and A2-Tunnel (Figure 4-4). This pathway was confirmed by all three tracers. The Leon Sinks to Wakulla Cave connection via K-Tunnel was previously established by tracing (Hazlett-Kincaid, 2004). A second pathway must connect to Sally Ward Spring (then to Wakulla Spring via the spring channel) because both uranine and eosin were recovered but phloxine-B was not. It is, however impossible to determine if it is an independent pathway or if the Ames/Kelly to Indian pathway bifurcates somewhere upstream of the siphon tunnel in Indian Cave where the phloxine-B was injected. Table 4-4 and Figure 4-23 show the distances between the documented pathways, the peak travel times, and the calculated groundwater velocities. The Indian to Wakulla path assumes a connection through the Leon Sinks Cave System as described above. Groundwater velocities are calculated from the peak travel times on the recovery curves. Very low tracer concentrations rendered the peaks for uranine and particularly eosin difficult to confidently define at the Wakulla and Sally Ward sampling stations therefore the error in velocity calculations is higher for those paths and tracers. Hazlett-Kincaid, Inc.

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Figure 4-21. Tracer recovery curves recorded at the Indian, Wakulla K-Tunnel, and Wakulla-Vent sampling stations during the 2005 Ames Sink groundwater tracer test, Woodville Karst Plain, Florida. All of the plots are normalized to the maximum recorded fluorescence and plotted against the days past the relevant injection to facilitate comparison. Groundwater velocities were calculated from the peak arrival times and the distance between stations. Straight-line flow paths were assumed between all stations except Indian to Wakulla K-Tunnel, which was assumed to connect through the Leon Sinks Cave System. The uranine and eosin peaks are difficult to confidently define at K-Tunnel and the Vent stations because of the very low tracer concentrations detected. Eosin was particularly problematic Hazlett-Kincaid, Inc.

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because it becomes masked when the uranine becomes detectable. However, under background conditions, the eosin should plot beneath uranine therefore the eosin peak is most probably reflected by the maximum positive deviation between the eosin and uranine curves.

Figure 4-22. Tracer recovery curves recorded at the Sally Ward sampling station during the 2005 Ames Sink groundwater tracer test, Woodville Karst Plain, Florida. The travel times for both the apparent peaks are approximately one day longer than the travel times recorded for the same tracers at the Wakulla Spring Vent. The slower travel times indicate that the Sally Ward pathway is less prominent than the pathway to Indian Cave and then to Wakulla Spring via K-Tunnel.

Figure 4-23. Comparison of distance, travel time, and calculated groundwater velocity for variations or segments of the observed flow pats between Ames and Kelly Sinks and Wakulla Spring in the Woodville Karst Plain, north Florida. There is an apparent exponential increase in groundwater velocity as the tracer approaches Wakulla Spring, presumably because the conduits in the aquifer become larger and carry more water as they approach the spring discharge.


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Hydraulic Relationship

Table 5-5. Travel times and velocities measured during the 2005 Ames Sink Tracer Test.

Figure 4-24 shows the uranine recovery curve Travel Groundwater relative to the hydrograph at Ames Sink spanning Distance Time Velocity the duration of the test, and the timing of the Ames Pathway (km) (days) (m/day) Sink injection relative to the hydrograph. The plot Ames – Indian 8.4 17.2 487 shows a correlation between a measured Kelly – Indian 8.4 13.5 608 depression in uranine fluorescence at the top of the Indian – K-Tunnel 7.4 5.4 1371 recovery curve that produces two obvious peaks, and the duration of flooding into Kelly Sink from K-Tunnel - Vent 1.2 0.5 2438 Ames Slough following the injection. The correlation suggests that the flow paths from Ames and Kelly sinks to Indian Spring merge somewhere close to the swallets, and that the depression is caused by dilution of the tracer from storm water that entered the flow path from Kelly Sink after a large part of the dye had already passed the junction. It follows from the intake capacities of the respective sinks (Table 4-4) and the tracer travel-times (Table 4-5) that the Ames section of the flow path is more restrictive than the Kelly section, C KS >> CAS where C is the conveyance capacity of the Kelly Sink (KS) and Ames Sink (AS) sections of the flow path. Under constant head and flow conditions, the width of the recovery curve would not only reflect longitudinal dispersion along the flow path, but also the CKS : CAS contrast. Figure 4-25 presents a diagrammatic sketch of the probable hydraulic head configuration around Ames and Kelly Sinks and a series of hypothetical tracer recovery curves that would be produced by 1) independent tracer injections when only Ames Sink is receiving water, and 2) an injection into Ames Sink followed by a flood of tracer-free water into Kelly Sink at various times relative to the transport of the tracer mass. In addition to the relationship between the conveyance capacity of the respective flow paths, the model presented in Figure 4-25 assumes that: 1) the pathway between Kelly Sink and Indian Spring is the primary groundwater flow path during low flow conditions; 2) flow along the Ames Sink section of the flow path is driven only by surface water runoff into the Ames Sink swallet; and 3) that surface water runoff into Kelly Sink only occurs as a result of flooding in Ames Slough that first overflows Ames Sink. All of these assumptions are supported by field observations. Flow into Kelly Sink has only been observed as a result of flooding in Ames Slough. During low flow periods, surface water stops flowing into Ames Sink and the water remains deeply tea-colored. During the same low flow periods, water clarity in Kelly Sink increases significantly to the point where the WKPP divers have explored the basin and a small connected cave and reported visibility similar to that observed in down-gradient springs. Moreover, their explorations have revealed that Kelly Sink is actually a karst window. They reported the conduit to be several feet in diameter; that it trends in both up-gradient and down-gradient directions for 100 or more feet; and that there was perceptible flow through the cave during their exploration. The models show that, under the assumed conditions, a tracer recovery curve associated with a Kelly Sink injection should be taller and narrower than a tracer recovery curve associated with an Ames Sink injection due to a faster travel-time. The expected recovery curve from an Ames Sink injection, is complicated by the CKS : CAS contrast in that once in the Ames flow path, the tracer massed would be released into the Kelly flow path at a rate slower than the velocity of the tracer once in enters the Kelly flow path. The resulting recovery curve should be nearly flat on top resulting from the slow continuous flux of tracer from the Ames flow path into to higher conveyance Kelly flow path, where the width of the curve at the flat part of the peak would be a function of primarily the CKS : CAS contrast. A short duration flood of tracer-free water into Kelly Sink at any point during the transit of the tracer would result in a depression in the tracer recovery curve where the width of the depression is related to the duration of the inflow and the height of the depression is related to the magnitude.


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Figure 4-24. Tracer recovery curve for uranine recorded at the Indian Spring sampling station during the 2005 Ames Sink tracer test, Woodville Karst Plain Florida relative to the hydrograph at Ames sink spanning the period of the test. The uranine was injected immediately prior to a flood in Ames Sink that overflowed into Kelly Sink from Ames Slough approximately 2 days after the injection. The uranine recovery curve contains two distinct peaks wherein the depression between the peaks approximately correlates in timing and duration to the duration of flow into Kelly Sink. We therefore interpret the depression as dilution in tracer concentration resulting from a short duration flood of tracer-free water into the combined Ames/Kelly – Indian flow path at about the time that the tracer mass was passing the junction between the Ames and Kelly components of the pathway.


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Figure 4-25. A) Diagrammatic model of the Ames/Kelly Sink to Indian Spring flow path and the probable hydraulic head configuration (dashed lines) associated with a constant flux of runoff into the Ames Sink swallet but no runoff into the Kelly Sink swallet. C1 and C2 denote the relative conveyance capacities of the Ames and Kelly sections of the flow path. B) Hypothetical tracer recovery curves (black lines) associated with independent injections into Kelly and Ames Sinks under the hydraulic conditions described for (A). The gray lines mark the influence of the C 1:C2 contrast on the height and width of the Ames Sink recovery curve. C-E) The effect of a short duration flood of tracer-free water into Kelly Sink at various times relative to the transit of the tracer center of mass past the junction between the two flow paths. C) The flood into Kelly Sink occurs as the tracer center of mass is entering the Kelly section of the flow path where the height of the depression in measured tracer concentration is controlled by the magnitude of the flux into Kelly Sink and the width is controlled by the duration. D) The flood into Kelly Sink occurs before the tracer center of mass enters the Kelly section of the flow path where the shape of the leading edge of the recovery curve ( A, B, C) is controlled by the magnitude and duration of the flood into Kelly Sink. E) The flood into Kelly Sink occurs after the tracer center of mass enters the Kelly section of the flow path where the shape of the tailing edge of the recovery curve (A, B) is controlled by the magnitude and duration of the flood into Kelly Sink.


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4.4.3 Spectrometer and IFF Comparison In 2005, we recommended that the FGS purchase an insitu filter fluorometer (IFF) that could be deployed in the field and used to automatically collect real time fluorescence measurements without the need for water sampling and laboratory analysis. Few such devices exist and most of those in existence are designed to measure one range of fluorescence, typically meaning one tracer. Such devices have limited utility because our research has grown to depend on the simultaneous injection and measurement of multiple tracers. We did however identify one device, the Schnegg downhole fluorometer (Schnegg and Kennedy, 1998), which permits the simultaneous measurement of three fluorescence ranges and turbidity. The design specifications indicated that the device should be able to efficiently measure green (uranine) and red (phloxine-B) fluorescence and that we may be able to calculate eosin fluorescence based on its cross-fluorescence into the green and red ranges. The device also measures blue fluorescence, which effectively tracks the fluorescence of natural tannins and turbidity, which can be an effective marker for surface water flow. Based on these specifications, we purchased two devices and deployed them during the 2005 Ames Sink tracer test. The purpose of the deployment was to 1) test the devices and compare the resulting data against analytical data obtained from water samples for which we have a high level of confidence; and 2) determine if the devices could be confidently used alone or nearly alone in future tracer tests, specifically the Southeast Spray Field test that was proposed for 2006 and is described in Section 6 of this report. The purpose of this section is to provide a comparison of the spectrometer and IFF data obtained from the Ames sink test. Two IFFs were deployed, one at the Indian sampling station, and one at the Wakulla Vent sampling station. Though the IFFs are designed to be deployed underwater and are rated to depths well beyond those in the WKP, the location of the sampling stations well within Indian and Wakulla Caves precluded actual deployment of the devices at the stations. Instead, IFFs were deployed into a light-sealed container on the land surface that received a continuous flow of water from the same sampling tubes that were used to collect the spectrometer water samples. Unfortunately, the Wakulla IFF was found to not be functioning correctly and had to be sent back to the manufacturer for repair. Thus, the Indian station provided the only data with which to perform the comparison. The IFF measures fluorescence by transmitting light in filtered excitation ranges for blue, green, and red bands of wavelength and then measures the resulting emitted filtered light in the respective filtered emission ranges. The IFF converts the collected light in the three separate ranges into voltage responses that are recorded in separate channels on a datalogger. The plots in Figures 4-26 – 4-30 show the voltage response as a measure of fluorescence. The IFF deployed at the Indian sampling station was programmed to record fluorescence every two minutes and operated continuously from May 13, 2005 at 9:06 PM to May 30, 2005 at 6:48 PM. Figure 4-26 provides a plot of the three fluorescence ranges and turbidity measured by the IFF. The data is provided electronically in Appendix V. The IFF data shows that the only signal that displayed a significant change in trend during the sampling period was the green fluorescence. There is a clearly defined rise and fall in green fluorescence that mimics the shape of the uranine recovery curve obtained from the spectrometer data, contains the same twin peaks observed in the spectrometer data, and shows that the estimated peak passed the sampling station approximately 17 days after the Ames Sink injection, which matches the uranine travel-time measured by the spectrometer data. The twin peak signal is also evident in the blue fluorescence. The pattern shows a slow rise, pronounced fall, pronounced rise, and pronounced fall in natural fluorescence, that indicates an addition of tannin-rich water into the flow path that was diluted over a relatively short-duration time period. One benefit of the IFF data is that it consistently measures both blue fluorescence and turbidity, which can both be used to measure changes in the source water entering the flow path. Both can therefore provide a proxy for changes in the background fluorescence in the green and red ranges, which can easily be filtered by subtracting the blue fluorescence or turbidity from the green or red readings.


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Afterward, the resulting green or red fluorescence curves should provide a cleaner and truer measure of fluorescence changes resulting from the presence of the injected tracers.

Figure 4-26. Fluorescence and turbidity measured by the insitu filter fluorometer (IFF) deployed at the Indian sampling station during the 2005 Ames Sink tracer test, Woodville Karst Plain Florida. The data shows a clear rise in the green fluorescence (a measure of uranine), that contains two distinct peaks at the top of the curve. The center of the two peaks was measured at approximately 17 days after the injection, which correlates to the arrival of the uranine peak measured by the spectrometer data (Figure 4-21) at the same station. Figure 4-27 shows a plot of the green-blue fluorescence relative to the uranine data measured by the spectrometer. Figure 4-28 shows a plot of spectrometer vs. IFF fluorescence and shows the correlation coefficients for the whole curve and the leading and tailing sections of the curve independently. The plots show that the two data sets are very well correlated, where the leading and tailing sections of the curve show higher correlation coefficients than the curves as a whole. The slight deviation is therefore primarily restricted to the region around the peak where the timing and magnitude of the twin peaks evident in the both the uranine data (Figure 4-24) and the raw IFF data for green fluorescence (Figure 4-26) have been attenuated. The presence of the twin peaks and apparent dilution in the green and blue fluorescence data and their attenuation after blue was subtracted from the green signal provides further evidence that the source of the dilution was the overflow into Kelly Sink described in Section 5.4.2. It follows that the rise in blue fluorescence reflects the flood into Ames Slough where the runoff water has sufficient residence time to incorporate tannins; that the depression in blue fluorescence reflects the overflow into Kelly Sink wherein runoff was flowing rapidly through the slough and into the Floridan aquifer before it could incorporate tannins; and that the subsequent rise in blue fluorescence marks the cessation of flow into Kelly Sink when the flood was subsiding and all recharge from the slough was again restricted to the lower capacity swallets (Ames and Ames2 Sinks). The presence of the twin


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peaks in the uranine data indicates that the spectrometer data reflects both the fluorescent signal generated by the uranine and that generated by the tannins.

Figure 4-27. Comparison of the Spectrometer and IFF data measured in Indian Cave during the 2005 Ames Sink tracer test, Woodville Karst Plain, Florida. The IFF plot shows the green minus blue fluorescence filtered to remove all points that deviate from a 4-hour moving average by more than 1  calculated over the same section of data; and the 4-hour moving average of the resulting dataset.

Figure 4-28. Spectrometer vs IFF data measured in Indian Cave during the 2005 Ames Sink tracer test, Woodville Karst Plain, Florida. Correlation coefficients are shown for the bulk curves, and the leading and tailing sections of the curves. Both the leading and tailing sections of the curves are almost identically correlated meaning that the deviation is restricted to the region around the peak where the twin peaks evident in the uranine data have been attenuated in the green minus blue fluorescence data. Hazlett-Kincaid, Inc.

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Figure 4-29. Fluorescence and turbidity relative to temperature measured by the insitu filter fluorometer (IFF) deployed at the Indian sampling station during the 2005 Ames Sink tracer test, Woodville Karst Plain Florida. The data shows a consistent negative correlation between (A) red fluorescence and temperature and B) turbidity and temperature. C) The correlation does not appear to hold for green and blue fluorescence.


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Figure 4-30. Fluorescence relative to turbidity measured by the insitu filter fluorometer (IFF) deployed at the Indian sampling station during the 2005 Ames Sink tracer test, Woodville Karst Plain Florida. The data shows a positive correlation between red fluorescence and turbidity but no apparent correlation between green or red fluorescence and turbidity. Neither the red fluorescence or turbidity show any obvious pattern that could be attributed to the inflow from Ames or Kelly Sinks, however both display an obvious diurnal signal that is negatively correlated to temperature (Figures 4-29). We attribute this correlation to the daily rise and fall of temperature in the sampling container at the land surface where the maximum temperature is recorded at approximately 6:00 PM and the minimum temperature at approximately 6:00 AM. The correlation between red fluorescence and temperature indicates that the design of the sampling station should be modified such that the temperature of the sampling reservoir is held more constant and preferably close to the temperature of the formation water. Figure 4-30 shows that the red fluorescence also correlates to turbidity, which indicates that red dyes can be more easily masked by background signals in tannin stained turbid stream water than green dyes. 4.4.4 Mass Recoveries Tracer concentrations were calculated for all water samples collected during the Ames Sink tracer test by calibrating measured peak heights on the spectrometer against known concentrations for standards prepared from each of the respective fluorescent dyes (Figure 4-31). Dye concentrations in the collected water samples were then calculated from the following equation:

CT  PHT  BGT   CST   CIT ; where:

CT  tracer concentration, PHT  tracer peak height measured on the spectrometer (FU), BGT  average of peak heights measured prior to tracer arrival, i.e. background signal (FU), CST  slope of the calibration curve for the respective tracer standards, and CIT  intercept of the calibration curve for the respective tracer standards (set to zero).


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Figure 4-31. Calibration curves for uranine, eosin, and phloxine-B plotted from standards calculated in May 2005 during the Ames Sink tracer test, Woodville Karst Plain Florida. The slope for each trend is shown next to the respective line along with the correlation coefficient R 2. The total mass of tracer recovered at each sampling station can then be determined from the calculated concentration in each sample, flow at the sampling station between samples, and the time lag between samples as follows: n

MRT   Qi  t i  t i 1   CTi / 1E 9 ; i 1

where:

MRT  total mass of tracer recovered at sampling station (g), Qi  flow past the sampling station at sample i (cms), t  time past tracer injection (seconds), and CT  calculated tracer concentration in sample i (ppb).

In order to accurately determine the mass of tracer recovered at each sampling station the following criteria must therefore be fulfilled. 

The tracer must be conservative, i.e. there can be no loss of tracer along the flow path due to adsorption/absorption, chemical reaction with the water or matrix, or biological degradation.



The full tracer recovery curve must be measured.



The water flow past the sampling station must be known when each sample is collected.



The background fluorescence must be calculated for each sample.



Sufficient tracer must be present in the sample to be measurable above the background fluorescence in the sample.

Figures 4-32 and 4-33 show the tracer recovery curves (in ppb) for the tracers detected at the Indian and Wakulla Vent sampling stations. Unfortunately none of the latter four criteria above were completely met at the sampling stations during the tracer test. Figures 4-21 and 4-22 show that the Hazlett-Kincaid, Inc.

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sampling periods were not long enough to record complete recovery curves for either uranine or eosin at any of the sampling stations. Complete recovery curves for phloxine-B were apparently measured at both K-Tunnel and the Wakulla Spring Vent though there are insufficient samples to confidently identify the background fluorescence levels at the end of the curves (Figure 4-21). Mass recoveries therefore reflect only the measured extent of the recovery curves except for the uranine curve measured at the Indian sampling station, which included a sufficiently well constrained tailing edge to extrapolate concentrations back to background levels (Figure 4-32). In each case however, it was impossible to be sure that some quantity of the tracers was not sequestered along the flow paths and therefore not measured in the recovery curves. Flow measurements were also problematic. The sampling stations were located in conduits, often deep within the cave systems. Flow across the sampling stations could not therefore be measured or estimated directly. Falmouth hydraulic meters (see Section 4.2.1) were installed at the Wakulla Spring Vent and Wakulla K-Tunnel during the tracer test, however the K-Tunnel meter was not functioning. A replacement meter was obtained but could not be deployed by the WKPP divers during the test due to poor water clarity conditions in Wakulla Cave. It was temporarily deployed at the Indian sampling station for a period of approximately two months immediately following the tracer test. The tracer recovery calculations shown in Figures 4-32 and 4-33 were based on an average of the flow measured during or as near to the tracer test as possible by the Falmouth meters installed at the Wakulla Spring Vent and Indian sampling station.

Figure 4-32. Uranine and eosin concentration recovery curves measured at the Indian sampling station during the 2005 Ames Sink tracer test, Woodville Karst Plain Florida showing the calculated percent of the injected tracers recovered at the station during the test. The uranine mass recovery incorporated an extrapolation of concentrations on the tailing edge of the curve to background levels based on an exponential curve fitted to the tailing edge of the recovery curve. The leading edge of the eosin curve was not measured due to a broken sampler. Both the leading edge of the uranine curve and the tailing edge of the eosin curve were masked by the presence of the other tracer in the water samples and thus concentrations were not calculated for those periods. The tailing edge of the eosin curve was not extrapolated because there were insufficient points on the tailing edge of the curve to yield a confident trend. Note that the phloxine-B was injected as the leading edge of the eosin curve was passing the sampling station indicating that the two tracers traveled nearly together down-gradient.


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Figure 4-33. Uranine, eosin, and phloxine-B concentration recovery curves measured at the Wakulla Spring Vent sampling station during the 2005 Ames Sink tracer test, Woodville Karst Plain Florida showing the calculated percent of the injected tracers recovered at the station during the test. The magnitude of the eosin curve is likely attenuated due to masking by both phloxine-B, which traveled simultaneously with the eosin, and uranine, which arrived slightly after the eosin but overlapped the recovery curve significantly. The background fluorescence levels were not measured specifically for each sample. Rather, the background levels for the mass recovery calculations were assumed to remain constant throughout the test and were assigned the estimated average fluorescence level measured for each tracer prior to the first arrival of the tracers at the sampling stations (Figure 4-21 and 4-22 and Appendix IV). We believe that this assumption resulted in an under estimation of the total mass recovered because the background fluorescence apparently declined during the course of the test (see the blue fluorescence trend in Figure 4-26). The recovery plots and calculations show that a relatively small amount of the injected tracers was recovered at the sampling stations. There are at least four possible explanations for the relative low recoveries. 1. A relatively large quantity of the tracers was carried by the groundwater to discharge points that were not sampled. The only reasonably possible such discharge would be Spring Creek springs as all of the other large magnitude springs in the basin were sampled. We believe that Spring Creek and Wakulla are hydraulically connected, probably by one or more conduits and that a groundwater divide crosses the conduit(s) somewhere between the southern part of Wakulla Cave and Spring Creek Springs (Werner, 1998; Kincaid, 1999; Loper, et al., 2005a). It is therefore possible that some portion of the water from Ames Sink could be flowing to Spring Creek Springs. Based on the lack of tracer detections in the Leon Sinks Cave System or McBrides Slough (Figure 4-18) however, such a diversion must occur south of Indian Cave and most likely within the southern part of Wakulla Cave. Further testing will have to be performed to evaluate the probability of a diversion to Spring Creek. 2. A large part of the tracers could have been sequestered in the conduits for a period longer than the sampling period minus the travel time from that point. Though we have observed sequestration in karst windows connected to the conduit flow paths and in large chambers within the conduits, such an occurrence should be evident in the tailing edge of the recovery curve, which it is not in any of the measured curves.


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3. A large part of the tracers could have passed the sampling stations at levels below the spectrometer detection limit, however, the mass recovery calculated from the measured and extrapolated tracer concentrations at the Indian sampling station indicate that this is unlikely. 4. A large part of the tracers could have adsorbed onto or absorbed into the conduit walls and/or aqueous organic compounds in the conduit flow. We believe this to be the most probable mechanism responsible for the low observed tracer recoveries supported as follows. Figure 4-34 provides a plot of the tracer concentration recovery curves calculated for the tracer test between Emerald Sink in the Leon Sinks Cave System and Wakulla Spring conducted by HKI and CGW in 2004 (Hazlett-Kincaid, 2004). For the purpose of this analysis, it is assumed that the recovery curve at Upper River Sink measured 100% of the injected tracer. The resulting flow at that location is 118.2 cfs (3.3 cms), which correlates to the approximate average flow measured at Turner Sink by a Falmouth hydraulic meter installed there for two weeks in December 2003. Mass recoveries calculated at Turner Sink, and Wakulla K-Tunnel and AK-Tunnel are based on an assumption of constant flow between Upper River Sink and those locations whereas the calculation at the Wakulla Spring Vent is based on the flow measured at that location during the tracer test by a Falmouth hydraulic meter. The assumption of constant flow between Upper River and Turner Sinks is reasonable based on the lack of mapped inflowing conduits between those two points in the Leon Sinks Cave System (Figure 4-4). The constant flow assumption between Turner Sink and Wakulla KTunnel may be underestimating flow by 30-50 cfs (1-1.5 cms) based on the traced connection between Indian Cave and Wakulla Spring (Figure 4-18) and the flow measured by a Falmouth hydraulic meter in at the Indian Cave sampling station in July 2005.

Figure 4-34. Uranine concentration recovery curves measured during the 2004 Leon Sinks – Wakulla tracer test, Woodville Karst Plain Florida showing the calculated mass recoveries and a plot of reduction in mass recovery vs. distance along the conduit flow path. Mass recoveries at Upper River Sink, Turner Sink, and Wakulla K-Tunnel and AK-Tunnel are based on an assumption of 100% recovery at Upper River Sink an assumption of constant flow between Upper River Sink and Wakulla K-Tunnel. The mass recovery calculated for the Wakulla Spring Vent is based on the average flow measured at that location during the testing period by the Falmouth hydraulic meter. Hazlett-Kincaid, Inc.

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There are three important things to note in Figure 4-34. 1. There is an apparent loss of nearly 75% of the tracer between Upper River and Turner Sinks, which are separated by only approximately 7000 feet along the main Leon Sinks conduit. 2. There is a significantly lower apparent loss of tracer between Turner Sink and Wakulla KTunnel and AK-Tunnel, which are separated by nearly 35,000 feet along the traced pathway. Note that if the flow was higher than the assumed value at K-Tunnel and AK-Tunnel the apparent loss would be further reduced. 3. There is no apparent loss between the K-Tunnel / AK-Tunnel junction in Wakulla Cave and the Wakulla Spring Vent, which are separated by nearly 4000 feet along the main Wakulla conduit. In the context of the above observations, there are two important things to note in Figure 4-33. 1. There is less than a 2% loss in the recovered uranine between the Indian Cave and Wakulla Spring Vent sampling stations. 2. There is an apparent 92% loss in the phloxine-B between the same sampling stations. In both plots the largest apparent loss in recovered tracer occurs nearest to the injection points where the tracer concentration is highest. This observation indicates that adsorption and/or absorption are likely mechanisms for the apparent decline in mass recoveries because either process will be most effective when the tracer concentrations are highest in the conduit water. Fluorescent dyes are known to be highly adsorptive on organic molecules such as charcoal, which provides the means by which charcoal traps have been shown to be effective dye collectors in qualitative tracer tests (Smart and Laidlaw, 1977; Alexander and Quinlan, 1992). The waters in the Ames Sink flow path and particularly within the Leon Sinks Cave System contain significant quantities of aqueous organic material derived from rapid infiltration from swallets and the conduit walls contain significant mineralization such as goethite. Both provide opportunities for significant adsorption and/or absorption. Though it is certainly possible that some portion of the water from Ames Sink was diverted to downgradient springs such as Spring Creek and thus not detected, the possibility that adsorption/absorption contributed significantly to the low apparent mass recoveries is strong. Further investigations need to be carried out to evaluate both of these possibilities such that the prominence of the respective flow paths can be effectively evaluated.


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4.5

AQUIFER PUMPING TEST ANALYSIS

An aquifer pumping test is a standard method of evaluating the transmissivity of an aquifer. The test depends on creating a measurable depression in the water table or potentiometric surface by pumping the aquifer at a constant rate for a specified period of time. The transmissivity can then calculated by analytically evaluating the change in head over time in observation wells at varying distances from the pumping well that occur during the pumping and recovery periods of the test. While these tests have been successfully utilized in porous media aquifers, their effective utilization in karst aquifers including the Floridan aquifer, has been limited primarily because even very high pumping rates rarely produce a definitive depression in head in nearby observation wells. The standard interpretation of such results is that the transmissivity of the aquifer is very high and that the pumping rate will not impact groundwater flow directions at even short distances away from the pumping well. The problems with this interpretation are: 1) that it typically leads to an assumption that the aquifer is isotropic and homogeneous even though the permeability structure of the aquifer is dominated by conduit flow, particularly in the unconfined regions; and 2) when used in predictive models, such an interpretation of transmissivity can and has led to under-predicted travel times and erroneously small predicted well capture zones. Aquifer pumping test data collected by the Wakulla Springs Water Bottling Company in 2005 and made available to HKI in 2006 provided an opportunity to evaluate the problem with pumping test analysis in relation to a relatively well-constrained conceptualization of the karst aquifer in which the pumping wells are situated. The test was conducted with two pumping wells and one observation wells located approximately 0.5 miles southwest of Cherokee Sink near the intersection of Wakulla Aaron Road and Spring Creek Highway, and within a few hundred feet of the mapped location of P-Tunnel in Wakulla Cave (Figure 4-35). Both wells were pumped at a rate of approximately 210 gallons per minute (GPM) for 24 hours. Groundwater levels were measured periodically at both pumping wells and regularly at the monitoring well for a period of approximately 8 days surrounding the 24-hour pumping period. The monitoring well was completed to 250 feet below sea level (BSL) and open to the aquifer below 140 feet BSL. The original analysis reported no definitive drawdown in the monitoring well during the pumping test, which is a standard interpretation of the data when evaluated independently. An overlay plot of head vs. time for all three wells (Figure 4-36A) shows a definitive drop in water table elevation in the pumping wells during the pumping period but a more ambiguous signal at the observation well. While there is an apparent decline in head during the pumping period, the magnitude of the decline is no greater than a subsequent depression in head measured after the pumping was terminated. Moreover, there is an obvious diurnal signal in the head measurements that is significantly larger than either of the two depressions. When viewed independently, it is therefore impossible to attribute the observed depression to aquifer pumping and therefore easy to conclude that the transmissivity of the aquifer is sufficiently high to render the cone of depression around the wells smaller in radius than the distance between the pumping wells and the observation well. A very different interpretation can be confidently rendered however, if the head data is evaluated in the context of spring flow and tide data, which describe hydraulic forces acting on the karst aquifer in the vicinity of the wells. Figure 4-36B shows the head fluctuations at the observation well relative to tide measured in Apalachicola Bay. From that chart, the diurnal head fluctuations in the observation well can be clearly attributed to tide. This indicates that there is a very efficient hydraulic connection between the Gulf coast and the aquifer in the vicinity of the observation well. Placing the well in the spatial context of proximity to Wakulla Cave (Figure 4-35), reveals that the most probable mechanism providing the requisite hydraulic connection is the southern conduits in Wakulla Cave that are trending toward the Gulf coast. The correlation between head fluctuations and tide is therefore more likely controlled by the proximity of the wells to the cave rather than the proximity of the wells to the Gulf coast.


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Figure 4-35. Map of part of the Woodville Karst Plain of north Florida showing the position of the pumping and monitoring wells relative to the conduits in the Wakulla Cave System and traced groundwater flow paths.


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A

B

Figure 4-36. (A) Plot of water level vs time in two pumping wells and one monitoring well during an aquifer pumping test conducted by J. Strickland in January 2005 for the Wakulla Water Bottling Company, Wakulla County Florida. Pumping for the aquifer test began at approximately 4140 minutes and lasted for approximately 1500 minutes, terminating at approximately 5640 minutes. This period is marked by approximately 3 ft of drawdown in the pumping wells and the pink square points in the monitoring well data. Strickland argued that there was no observable water level decline in the monitoring well due to the pumping, however, there is a noticeable depression in the trend of peak water levels during the pumping period. (B) Plot of water level vs time in the observation well compared to tide measured in Apalachicola Bay, Florida. Note the correlation between tide and the diurnal rise and fall of water levels in the observation well, which indicates a highly conductive connection between the aquifer at the well and the coastal discharges such as Spring Creek springs. Hazlett-Kincaid, Inc.

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The probable hydraulic connection between the wells and the conduits in Wakulla Cave is borne out by a comparison of head fluctuations at the observation wells and flow at Wakulla Spring (Figure 437). Moreover, by comparing the well water levels against flows in the individual tunnels, the relative degree of hydraulic connection can be constrained to specific tunnels in the cave thereby allowing a more insightful prediction of the contribution zone for the wells. Figure 4-37 compares the monitoring well data to flow measured at the Wakulla Spring Vent and BTunnel in Wakulla Cave during the pumping test period (Hazlett-Kincaid, 2006). Both the water level and Vent flow data show the same diurnal tidal signature wherein there is no discernable shift between the peaks in both datasets demonstrating the hydraulic connection between the wells and spring. Rather than an independent analysis of water level fluctuations in the well, the correlation between the trends in peak magnitude plotted for the spring flow data and the water level data provide a qualitative means of evaluating the aquifer response to pumping. Figure 4-37 shows that the shape of lines connecting the peaks for each plot correlate well except during the pumping period. During that time, the trend in peak magnitude for the water level plot deviated negatively away from the trend in peak magnitudes for the Vent flow but re-established the correlation after the pumping was terminated. We attribute that negative deviation to drawdown in the aquifer due to pumping and the return to correlation to recovery in the aquifer after the pumps were stopped. Such an evaluation indicates that the transmissivity of the aquifer is significantly lower than would be predicted by a standard interpretation, and that the cone of depression associated with the pumping is large enough, not only to incorporate the observation well, but also large enough to intercept the nearest conduit in Wakulla Cave. In effect, the conduits in Wakulla Cave are providing a relatively constant source of water to the pumping wells and therefore the contribution zone for the wells must include the contribution zone for the conduits.

Figure 4-37. Plot of water level vs time in a monitoring well during an aquifer pumping test conducted by J. Strickland in January 2005 for the Wakulla Water Bottling Company, Wakulla County Florida Hazlett-Kincaid, Inc.

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compared to flow measured at Wakulla Spring (Vent Flow) and in B-Tunnel within Wakulla Cave (BTunnel Flow) during the same time period. Pink boxes mark the water levels measured during the pumping period. There are three probable hydraulic signals reflected in the data. 1) The oscillations evident in both the water level and Vent flow data are attributed to tide. The direct correlation indicates that the well is in excellent hydraulic connection with the spring, which is also supported by the close proximity of the well to conduits in Wakulla Cave. 2) Both the water level and flow data show a declining trend over most of the measurement period and then the beginning of an upward trend toward the end. These trends are marked by lines drawn on the plot through the data. A thin line connects the tidal peaks in the Vent flow data. A heavier line connects the related tidal peaks in the water level data. And, a trend line marks decreasing flow in B-Tunnel. 3) There is an apparent decline in water levels in the monitoring well during the pumping period, as indicated by the shaded triangle (A), which marks a deviation between the otherwise well-correlated trend in tidal generated peaks in both the water level and Vent flow data. A closer evaluation of the head and flow data is capable of identifying the most probable section of the cave that is contributing water to the wells. Wakulla Cave can be generally divided into two sections that provide water to the spring from different sources: a southern section that contains the conduits closest to the wells and deliver water to the spring from the south, and a northern section containing conduits that deliver water to the spring from the north. Figure 4-35 shows the position of the FGS Falmouth meters installed in Wakulla Cave, which record water flow at those locations in the cave. Unfortunately, the K-Tunnel and AK-Tunnel meters were inoperative during the pumping test. Figures 4-37 through 4-39 therefore focus on a comparison of the head data to flow at the spring vent as a proxy for flow in the southern section of the cave, and flow in B-Tunnel to evaluate the northern section of the cave. Figures 4-37 and 4-39 show that the head fluctuations are positively correlated to flow at the spring vent whereas Figures 4-38 and 4-39 show that the head fluctuations are less correlated and perhaps negatively correlated to flow in B-Tunnel. From these correlations, it is therefore possible to constrain the hydraulic connection between the wells and the cave to the southern conduits. In addition to more adequately describing the impact to the aquifer effected by the pumping at the wells and the associated well capture zones, the more detailed analysis of the pumping test data also provides significant insight into the hydraulic mechanisms controlling groundwater flow through the aquifer. The positive correlation between flow at the spring vent and head in the wells indicates that tidal fluctuations are affecting the groundwater divide between Spring Creek and Wakulla Springs. At high tide, the elevated head over Spring Creek is very likely causing a reduction in discharge that shifts the divide to the south allowing more flow to travel northward to Wakulla Spring (i.e. increased flow at the spring vent). At the same time, the higher tide is reducing the regional groundwater gradient and thereby reducing the groundwater flow from the north toward the spring (i.e. decreased flow in BTunnel). At low tide, the reduced head over Spring Creek springs is very likely causing an increase in discharge that shifts the divide to the north reducing the northward flow of water to Wakulla Spring (i.e. decreased flow at the spring vent). The lower tide, however also results in a steeper regional groundwater gradient that causes an increase in southward groundwater flow to the spring (i.e. increased flow in B-Tunnel). These correlations compare favorably to the correlations between extreme high and extreme low tides and spring flow associated with the passing of hurricanes Francis and Ivan that were discussed by Loper and others (2005a). Accordingly, the evaluation of continuous water level measurements associated with aquifer pumping tests in comparison to other relevant hydraulic data offers far more insight into both the impact of the pumping and the hydraulics of the aquifer than has been typically obtained through standard independent analyses.


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Figure 4-38. Plot of water level vs time in a monitoring well during an aquifer pumping test conducted by J. Strickland in January 2005 for the Wakulla Water Bottling Company, Wakulla County Florida compared to flow measured at Wakulla B-Tunnel within Wakulla Cave (B-Tunnel Flow) during the same time period. Pink boxes mark the water levels measured during the pumping period. Though there is a somewhat diurnal signal in the B-Tunnel flow data, the peaks do not correlate to peaks in the water level data from the observation well but rather appear to be correlated to the troughs. The plot indicates that flow in B-Tunnel was not affected by pumping during the pumping test.


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Figure 4-39. Plot of flow at the Wakulla Spring Vent and Wakulla B-Tunnel vs. water levels measured in an observation well during an aquifer pumping test conducted by J. Strickland in January 2005 for the Wakulla Water Bottling Company, Wakulla County Florida. There is a strong correlation between flow at the Wakulla Spring Vent and water level in the observation well but no apparent correlation between the water levels and flow in Wakulla B-Tunnel.


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4.6

PROFESSIONAL PRESENTATIONS

One of the key objectives of the WKP research is to broaden the understanding of karstic controls on groundwater flow and therefore groundwater resource management issues both in the WKP and throughout the karstic regions of Florida within the professional hydrogeologic communities and the general public. One key way to facilitate that goal is to consistently deliver presentations on the evolving understanding of the WKP at public and professional venues. In that regard, HKI delivered the following presentations in FY 2005-2006. 

July 2005 Sierra Club Meeting: Hydrogeology of the WKP, Tallahassee, Florida.



September 2005 American Society of Civil Engineers – GEO Institute: Tenth Multidisciplinary Conference on Sinkholes and the Engineering and Environmental Impacts of Karst, San Antonio Texas (Kincaid et al., 2005).



November 2005 Pennsylvania Department of Environmental Protection, Norristown Pennsylvania.

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November 2005 Global Underwater Explorers: First Annual Conference of the Global Underwater Explorers, Gainesville Florida.



January 2006 US Geological Survey Water Resources Division, Reston Virginia.

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March 2006 American Water Resources Association: Florida Chapter Meeting, Tallahassee Florida.

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April 2006 Wakulla Springs State Park: Wakulla Wildlife Festival, Walulla Springs State Park, Florida.

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May 2006 Florida Department of Environmental Protection: Progress Report Meeting on the SESF Tracer Test for DEP Secretary Castille and her staff, Tallahassee Florida.



May 2006 Wakulla Spring Working Group Meeting: Progress Report on the SESF Tracer Test, Tallahassee, Florida.


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4.7

RECOMMENDED ACTIONS

4.7.1

4.7.2

4.7.3

4.7.4

Cave Mapping 

The WKPP conducted extensive exploration and surveys of both the Leon Sinks and Wakulla Cave Systems in late 2006 that was not included in the map revisions presented in this report. The existing maps and GIS coverages should therefore be revised to include their most recent data and discoveries.



Compile width and height data from the WKPP survey data and notes, synthesize that data with the revised cave maps, and add all of the WKP underwater caves into the Florida Cave Database such that they can be made available for use in other hydrogeologic characterizations and studies.

Confining Unit Delineation 

Synthesize field notes on the outcropping of the confining unit in the WKP from FGS geologic mapping efforts and use that data to augment the existing confining unit thickness datasets and maps.



Publish the confining unit map of the WKP.

Tracer Testing 

Expand the tracer testing and flow path mapping efforts to the St Marks and Wacissa river basins. The primary focus should be to map and characterize pathways emanating from the large swallets in the northeastern part of the WKP.



Conduct tracer tests from points north of the boundary of the unconfined section of the Floridan aquifer to down-gradient springs. The purpose of such tests would be to characterize flow paths and rates through the confined part of the aquifer where little is currently known about the influence and significance of karst conduits. One opportunity would be to inject tracers at Lake Jackson, Lake Iamonia, and/or Lake Lafayette and sample at the City of Tallahassee and Florida State University pumping wells and the down-gradient springs.



Conduct a series of laboratory experiments to evaluate the influence of aqueous organic compounds (i.e. tannins) and different solid substrate (i.e. cave wall and mineralization) on potential adsorption/absorption of the fluorescent tracers that we have utilized in the WKP. The overall purpose of the experiments would be to develop a set of adsorption isotherms such that we can predict the impact of varying quantities of aqueous organic material and varying substrate on fluorescence levels. This would allow for improved expectations of mass recoveries in future fluorescent tracer tests.



Repeat the 2004 Leon Sinks tracer tests with both fluorescent and non-fluorescent deliberate tracers in order to characterize the extent to which the fluorescent tracers are conservative. If its found that adsorption/absorption is a important factor in mass recovery calculations, the goal would be to correlate mass recovery with measureable parameters that mark the adsorptive/absorptive capacity of the water and cave system. One such parameter would likely be the natural fluorescence of the water for which the IFFs provide a easy means for measurement.

Aquifer Testing 

Record diurnal head fluctuations in wells and sinkholes distributed throughout the WKP and contour the magnitude of the diurnal signal and the lag between the signal and coastal tide gauges. This will allow an indirect measure of conduit connectivity distributed throughout basin and provide a check against the geophysical mapping that can also be compared to tracer test results.



Develop a series of aquifer stress tests at wells located at varying distances away from mapped conduits such that head measurements in the wells can be compared to spring


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discharges from the conduits. The purpose of these tests would be to explore the stress/flow relationships identified in the Wakulla Water Bottling Company data and develop a better methodology for evaluating pumping tests in the karstic aquifers to measure impacts associated with groundwater withdrawals. The tests would capitalize on existing wells near mapped conduits such as the three FGS wells installed near the upper part of the Leon Sinks Cave System or potentially private wells in cooperation with their owners. The tests would be run over a prolonged period of between 72 hours and 1-2 weeks, which would allow a more confident delineation of trends and relationships between head and flow data.


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5

TASK-9: MULTIPLE TRACER STUDIES AT THE TALLAHASSEE SPRAY FIELD

5.1


This task provided for a series of progressively scaled tracer tests utilizing both fluorescent dyes and bacteriophage as tracers to be conducted at the City of Tallahassee’s SE Farm Facility (SEFF) by HKI, CGW, and the USGS. Three scales of investigation were addressed. The first focused on the region underlying the SEFF and the region immediately south of the SEFF. The second and third tests addressed the entire region encompassing the flow path(s) between the SEFF and down-gradient springs. Tracer injections were performed in suitable wells and the Turf Pond sinking stream within the SEFF. Sampling locations included suitable wells within the SEFF and the major down-gradient springs in the St. Marks and Wakulla River watersheds. A field reconnaissance was performed to identify sinkholes in the Woodville region potentially suitable for intermediate injections and/or sampling where the criteria for suitability was an observation of flowing water. None were identified. HKI and CGW were responsible for the design and setup of the dye tracer tests, periodic sample analysis, interpretation of the dye tracer data, and reporting on the dye tracer results. FSU assisted in these tasks by providing field support for the setup of the dye tracer tests and the collection of the dye tracer water samples. FSU and the FGS performed the field reconnaissance. The USGS was responsible for the design and setup of the bacteriaphage tracer tests, collection and analysis of the bacteriaphage samples, interpretation of the baceriaphage tracer data, and reporting on the bacteriaphage tracer results. Specific deliverables for this task include:

5.2



Letter report outlining the design and schedule for the short-scale and long-scale tracer tests.



Letter report outlining the results of the short-scale tracer tests and the sinking stream (SEFF) trace including maps documenting the tracer pathways and an estimation of hydraulic parameters based on breakthrough curve analyses.



Website documenting the results of the short-scale tracer tests and the sinking stream (SEFF) trace.



Formal report outlining the results of all phases of tracer testing including detailed maps of injection locations, maps delineating the tracer pathway(s) and an estimation of hydraulic parameters based on breakthrough curve analyses.

PROJECT STATUS

HKI and CGW designed and carried out the fluorescent tracer testing component of the project. Three tracers were injected at two different times to investigate the short-scale and long-scale flow paths from the SESF to the down-gradient springs. Sampling and analysis has been conducted at several down-gradient wells and springs with both automatic water samplers and the use of a scanning spectrofluorophotometer for analysis and IFFs. Tracer recovery curves have been measured at wells SE-10, SJ-1, and SJ-2 and at spring locations: Wakulla Spring Vent, Wakulla B-Tunnel, Sally Ward Spring, Indian Cave, and McBrides Slough. As of July 2006, the primary objectives for the project were completed successfully. Flow paths from the SESF to the Wakulla area springs were successfully identified and partially characterized. No flow paths to the St. Marks River areas springs were observed thereby indicating the the springshed divide between the Wakulla area and St. Marks area springs lies east of the SESF. As the project neared completion from a budgetary standpoint, it became apparent however, that the injected fluorescent tracers were continuing to pass one or more of the sampling stations, primarily SE-10, B-Tunnel, and possibly McBrides Slough. This observation indicated that the tracers were likely leaving the SESF region as independent slugs where the travel times for each slug are affected by local variability in permeability and karstification and possibly changing hydraulic conditions. As a result of those observations, a proposal was submitted to the FLDEP Springs Initiative Program to extend the sampling and analysis phase of the tracer test in order to fully capture the recovery curves for the injected tracers at the down-gradient springs and then interpret the results of the tracer Hazlett-Kincaid, Inc.

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test in the context of the full recovery record rather than the partial record that had been collected as of July 2006. The proposal was funded and the sampling at the springs has continued to the present time. Sample analysis and data interpretation is scheduled to begin in March 2007 and should be completed by July 2007. The following is a brief synopsis of the design, execution and results of the SESF fluorescent tracer testing as of July 2006. A more in depth description of the test and the results will be delivered as a separate report once the continuation of the project scope is completed. 5.2.1 SESF Fluorescent Tracer Test Design Two sets of tracer injections were performed at wells SE-06, SE-11S, and SE-40 located across the northern section of the SESF. The first set of injections was performed on January 26, 2006 wherein 5 kg of the fluorescent dye phloxine-B (C.I. AR-92) was gravity fed to approximately the middle of the open-hole interval in each well. The second set of injections was performed in the same manner on March 9, 2006 using 20 kg of the fluorescent dye uranine (C.I. AY-73) in each well. One injection was performed at Turf Pond Sink, which is an ephemeral sinking stream located in the east-central section of the SESF on March 9, 2006 wherein 60 kg of the fluorescent dye eosin (C.I. AR-87) was released from twelve 5 kg pails into the stream flowing into the sinkhole. Beginning either before or immediately following the tracer injections, continuous (2-4 samples per day) or grab sampling (1-3 samples per week) has been conducted at the following locations: SESF wells SE-50, SE-22, SE-22A, SE-21, SE10, and SE-51; USGS wells SJ-1 and SJ-2; and natural discharge features St. Marks River upstream of Natural Bridge, St. Marks River Rise, Rhodes Spring, Monroe Spring, Newport Spring, Wakulla B-Tunnel, Wakulla Vent, Sally Ward Spring, Indian Spring, and McBrides Slough. Less frequent grab samples have been collected at USGS well SJ-7 since April 2006 and at vents 1 and 2 of the Spring Creek Spring Group since June 2006. Sampling at Wakulla Spring and the St. Marks River Rise has continued to present. Sampling has continued to a limited extent to present as well. Figure 5-1 provides a map that shows the locations of all injection and sampling locations. 5.2.2 SESF Fluorescent Tracer Test – Interim Results One or more of the injected tracers have been detected at the following locations: wells SJ1, SJ2, SJ7, SE10, and springs Wakulla B-Tunnel, Wakulla Vent, Sally Ward Spring, Indian Spring, and McBrides Slough (Figure 5-1). The injected tracers have not been detected at: the St. Marks River upstream of Natural Bridge, the St. Marks River Rise, Rhodes Spring, Monroe Spring, or Newport Spring. The strongest detection in the well sampling stations, in terms of concentration, has occurred at SE-10 wherein the tracer recovery curve associated with that detection continues to rise. The strongest detection in the spring sampling stations, in terms of concentration, has occurred at Wakulla B-Tunnel. The travel times from the injection locations to Wakulla B-Tunnel, as determined by the arrival of the peak concentration on the tracer recovery curves, were approximately 66 days for the first set of well injections and approximately 58 days for the second set of well injections and the sinking stream injection. Though tracer mass recoveries have not been determined for the spring sampling stations, it appears from the detection levels that only a small fraction of the tracers injected in the wells and sinking stream have been recovered at this time. Tracer recovery curves for the well sampling stations with highest tracer detection levels are presented in Figures 5-2 through 5-5. Tracer recovery and fluorescence curves for the Wakulla B-Tunnel sampling station are presented in Figures 5-6 and 5-7. The groundwater velocities presented in all figures and subsequent discussions were calculated by dividing the distance between the injection and sampling points by the time lag between the respective injection and the arrival of the peak concentration on the tracer recovery curve. Thus far, we’ve gained the following knowledge from the results of the SESF 2006 tracer study. 

One or more conduit flow paths connect one or more of the injection wells (SE-06, SE-11S, SE40) to USGS wells SJ-1 and SJ-2. This connection was established by the recovery of the phloxine-B tracer from the first set of well injections and a plot of the subsequent recovery curve as the tracer passed the sampling stations. The connection was confirmed by the recovery of the


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uranine tracer from the second set of well injections, a plot of the subsequent recovery curve, and a curve-shaped rise and fall in green wavelength fluorescence at the SJ-2 sampling station that is being measured by an insitu fluorometer. The apparent velocity along this flow path ranges from 160 m/day to 190 m/day. 

A conduit flow path connects the Turf Pond sinking stream to the USGS wells: SJ-1 and SJ-2. This connection was established by the recovery of the eosin tracer injected into the Turf Pond sinking stream and a plot of the subsequent recovery curve as the tracer passed the sampling station. The apparent groundwater velocity along this flow path is 200 m/day.



A conduit flow path connects the Turf Pond sinking stream to the USGS well SJ-7. This connection was established by the measurement of the eosin tracer that was injected into the Turf Pond sinking stream in several water samples collected from that well in April and May 2006. An apparent groundwater velocity along this flow path has not been calculated because there have been an insufficient number of samples collected to develop a recovery curve from which a peak can be measured. The tracer recovered there was only that injected directly into a conduit so the velocity should be at least comparable to other velocities obtained in conduits (herein) or somewhat quicker with the inferred direct connection.



One or more conduit flow paths connect one or more of the injection wells (SE-06, SE-11S, SE40) to SESF well SE-10. This connection was established and confirmed by the recovery of the tracers from both the first and second set of well injections and plots of the subsequent recovery curves as the tracers passed the sampling station. The recovery curves for both tracers show three separate peaks in tracer concentration indicating the presence of at least three separate flow paths from the injection wells to the SE-10 well. The groundwater velocity along these probable pathways ranges from 100 m/day for the first peak to 20 m/day for the third peak. The recovery curve for the uranine tracer is still rising however, which means that the slowest velocity might be slower than can be currently measured.



At least one conduit flow path connects the SESF to Wakulla Spring via B-Tunnel in Wakulla cave. This connection was established by the measurement of very low concentrations of the phloxine-B tracer from the first set of well injections and a plot of the recovery curve. The connection was confirmed by the recovery of the uranine and eosin tracers from the second set of well injections and the sinking stream injection, an on-going plot of the recovery curves, and a curve-shaped rise and fall in green wavelength fluorescence at the Wakulla B-Tunnel sampling station that is being measured by an insitu fluorometer. Another confirmation of this flow path was provided by the subsequent detection of all three tracers at the Wakulla Spring Vent. The groundwater velocity along this pathway was slightly different during the two tracing periods. The velocity as determined by the phloxine-B tracer test that began in January 2006 was between 270 and 280 m/day. The velocity as determined by the uranine and eosin tracer tests that began in March 2006 was between 310 m/day (uranine) and 330 m/day (eosin).



At least one conduit flow path connects the SESF to Sally Ward Cave. This connection was established by the measurement of low concentrations of uranine from the second set of well injections in 35 water samples collected between April 19 and May 23, 2006. Currently, the tracer recovery curve is noisy and contains gaps due to recurring problems with the sampling equipment. The last sample that was analyzed from this station was collected on May 23, 2006 and contained both the uranine and eosin tracers.



At least one conduit flow path connects the SESF to Indian Cave. This connection was established by the measurement of low concentrations of uranine from the second set of well injections and eosin from the sinking stream injection in 75 water samples collected from the upstream conduit in Indian Cave between April 15 and May 26, 2006. Currently, the tracer recovery curve is low and noisy. The last sample that was analyzed from this station was collected on May 26, 2006 and contained both the uranine and eosin tracers. The tracer concentrations measured in the samples analyzed thus far indicate that this pathway carries less water from the points of injection than the pathway to Wakulla Spring via B-Tunnel in Wakulla cave.


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Previous tracing from Ames Sink in 2005 (see Section 5.4) demonstrated that a significant part of the water passing through Indian Cave bypasses Indian Spring and flows both to A) D-Tunnel in Wakulla Cave via a probable conduit that connects the upstream reaches of Indian Cave to DTunnel, and B) to the Leon Sinks Cave system via a siphoning tunnel downstream of Indian Spring. At least part of the flow along this pathway was shown to discharge at Wakulla Spring via a conduit connection to the southern reaches of Wakulla Cave and then northward flow to the spring. Another part of this flow might bypass Wakulla Cave to discharge at Spring Creek via a hypothesized conduit that connects the Leon Sinks Cave system to one or more of the Spring Creek spring vents.

5.3



At least one conduit flow path connects the SESF to the McBrides group of springs. This connection was established by the measurement of low concentrations of uranine from the second set of well injections in 25 water samples collected between April 5 and May 23, 2006 and eosin from the sinking stream injection in 32 water samples collected between April 8 and May 26, 2006. The recovery curves are significantly noisier than those from Wakulla B-Tunnel containing frequent samples containing undetectable levels of the tracers. Consistent tracer detection did not begin until May 10, 2006 and even then the curve contains some samples containing undetectable levels of the tracers, particularly uranine. The last sample that was analyzed from this station was collected on May 26, 2006 and contained only the eosin tracer. The tracer concentrations measured in the samples analyzed thus far indicate that this pathway carries less water from the points of injection than the pathway to Wakulla Spring via B-Tunnel in Wakulla cave.



Based on the data collected to date, Wakulla Spring via B-Tunnel in Wakulla cave is the dominant discharge point for groundwater flowing beneath the SESF and ephemeral recharge to the Floridan aquifer through the Turf Pond sinking stream.



The apparent velocity of the phloxine-B tracer was slower than that of the uranine tracer along both the SESF wells – SJ-2 and SESF wells – Wakulla B-Tunnel flow paths. The phloxine-B injection was performed on January 26, 2006, which corresponds to the beginning of a significant rise in a significant and precipitous rise in groundwater levels as recorded by a pressure transducer in USGS wells SJ-1 and SJ-2 (Figure 5-8), and river stage as recorded by the USGS gauging station on the lower St. Marks River (Figure 5-9). The uranine injection was performed on March 9, 2006, which corresponds to the beginning of prolonged falling groundwater levels and river stage as measured by the same recording devices (Figures 5-8 and 5-9). These data indicate that there is potentially a negative correlation between the velocity of groundwater flow along the pathway between the wells and Wakulla Spring, and stage in the sinking streams.

PLAN OF ACTION FOR CONTINUATION OF THE STUDY

We believe that the positive tracer detections obtained at the SJ wells and Wakulla, Indian, Sally Ward, and McBrides springs were tracing the movement of the tracer from the one well. Also, as of August 2006, a second slug of tracer was being tracked at SE-10. Based on these observations, we believe that the tracer in the remaining two injections wells is either trapped in a low-flow region of the SESF flow field or that it is traveling much more slowly through lower permeable sections of the aquifer. We expect that evidence of this second tracer slug will also be detected at the USGS wells SJ1 and SJ2 and subsequently at the down-gradient springs. Successfully tracking this slug will allow us to map the secondary flow paths and describe the hydraulic characteristics of those pathways. To investigate this hypothesis we have extended the sampling period from July to present and will likely continue for the next 1-2 months until our sampling equipment is needed for other projects. The samples collected since July 2006 have been stored but not analyzed. Our effort for the project continuation will therefore focus on analysis and interpretation of the data that has been collected and stored as well as all additional data that is collected in the first part of 2007.


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R e p o rt of In v estig atio ns: 2 0 0 5 - 2 0 0 6

F i g u r e 5 - 1. M a p s h o w i n g t h e l o c a ti o n s of i nj e c ti o n a n d s a m p li n g p o i nt s u s e d i n t h e 2 0 0 6 S E S F tr a c e r s t u d y a n d t h e g r o u n d w a t e r fl o w p a t h w a y s c o n fir m e d fr o m t h e tr a c e r te s t r e s ult s.

Ha zl ett- Kin c ai d, Inc.

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Figure 5-2. Tracer recovery curve for sampling station: monitor well SJ-1.

Figure 5-3. Tracer recovery curve for sampling station: monitor well SJ-2.


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Figure 5-4. IFF fluorescence curve for sampling station: monitor well SJ-2.

Figure 5-5. Tracer recovery curve for sampling station: monitor well SE-10.


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Figure 5-6. Tracer recovery curve for sampling station: Wakulla B-Tunnel.

Figure 5-7. IFF fluorescence curve for sampling station: Wakulla B-Tunnel.


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Figure 5-8. Groundwater levels measured in USGS wells SJ-1 and SJ-2 between November 2005 and August 2006.

Figure 5-9. River stage measured at the USGS gauging station on the upper St. Marks River between January 2006 and December 2006.


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6

TASK-3: WKP HYDROGEOLOGIC MODELING

6.1

PROBLEM

Karst aquifers worldwide account for some 60% of groundwater supplies. Karst aquifers are also the most sensitive in their vulnerability to contamination. A better understanding and mastery of flow through karst aquifers can only lead to better protection and management of these valuable resources. The problem posed here was to model a karst aquifer with success. The question was whether we could use existing technologies to simulate flow in karst. Others have tried to simulate groundwater flow in karst, with varying degrees of success, but none were able to solve the fundamental problem of incorrect velocities, which has tremendous implications for age dating and contamination. So, has this been a failure of technology or of conceptualization? We posit that proper conceptualization of the problem is the key to successfully modeling flow in karst. In 2005, we modeled the WKP using a fully Darcian approach and the results were that we had a difficult time calibrating to velocities. In 2006, we have applied a discrete element conceptual model based approach with outstanding results using the software package FEFLOW (www.wasy.de). The current approach is multi-pronged and relies heavily on tracing data and cave diving for location of pathways (and velocities). It also relies on a geologic conceptualization of how caves relate to flow through the aquifer to assign cave pathways where they are indicated by head patterns or spring fluxes. What we have found is that although a standard MODFLOW type approach may be a fair approximation of the aquifer behavior at a regional scale, a discrete element approach is better for more specific problems where spatial detail and less computational burden is warranted.

6.2

PURPOSE & OBJECTIVES

Expand and refine a steady-state groundwater flow model of the WKP that HKI developed in FY 20042005 (Hazlett-Kincaid, 2005) such that it specifically addresses the known or hypothesized karst conduit controls on groundwater flow through the basin and is calibrated to measured or estimated average discharges at Wakulla, Spring Creek, and Wacissa Springs and the St. Marks River Rise, and measured velocities along the karst flow paths. Furthermore, to develop a modeling tool which can be used to intelligently support resource use and impact decision-making in terms of water quality and quantity within the upper Floridan aquifer and at the springs. The long-term objectives include use of the model as a tool for MFLs and TMDLs calculations. Also, it is hope that the model will spark interest in applying a similar approach to solving problems across the karst belt of Florida and elsewhere in the world where karst aquifers are being comprised.

6.3

CONCEPTUALIZATION AND MODEL DESIGN

6.3.1 Model Area & Boundary Conditions The model area encompasses 6.16E+09 m 2. The boundaries of the model (Figure 6-1) consist of no flow boundaries and constant head boundaries. The constant heads are 21 m along the northern boundary and 0 m along the coast. As one can see by the fact that the model domain is superimposed on a potentiometric surface map (Davis, 1996), the 21 m head is derived from that map, as are the no flow boundaries. The model extends from the Ochlocknee River on the west, along the Apalachee Bay and Gulf of Mexico to the south, then north along the Aucilla River, where it then cuts across the northern boundary, following the 21 m head line from the earlier model. The model area was designed to be large enough for investigation of the Wakulla Spring system without experiencing boundary effects. It was also considered in the design that eventually the scope of the investigation may expand to the other spring cave systems in the basin, including St. Mark’s Wacissa, and Spring Creek. In fact, work is slated for 2007 to investigate the linkage between Leon Sink and Spring Creek as well as Lost Creek and Spring Creek. 6.3.2 Conceptualized Hydrogeologic Framework & Numerical Design The model consists of a single hydrostratigraphic layer consisting of the freshwater portion of the Upper Floridan aquifer. The hydrostratigraphic layer consists of four numerical slices, three layers, Hazlett-Kincaid, Inc.

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316,608 nodes, and 472,392 hexahedral elements. The top slice represents the top of the Floridan aquifer. This was derived from FGS data from the FAVA project. A second slice was included to allow for the inclusion of the rivers. Another slice is included for the cave systems; taken at an average of about 76 m below the top of Floridan, and a fourth slice marked the bottom of the model. Caves, traced pathways, and inferred pathways were all included in the model (Figure 6-2) as discrete linear conduits where flow through the conduits is described by the Manning-Strickler equation. Conduit cross-sectional areas ranged from 1.48 to 830 m 2. Roughness coefficients for the conduits ranged from 0.025 to 100 where the smaller roughness coefficient produced less resistance to flow. The conductivity of the upper Floridan aquifer was assigned as a constant value of 0.0005 (m/s). There was no recharge or pumping assigned in this model. The numerical design (see Appendix VI for equations of flow) of this finite element model is one with Darcian porous media flow assumed over most of the basin, with the exception of sometimes large, discrete conduits embedded in the flow matrix. Flow through the discrete elements is solved as a term embedded in the standard matrix equations for Darcian flow (see Equations 15 & 16 in Appendix VI). When the flow matrices are solved for head, the model checks to see if the node at which the head is being calculated represents the aquifer matrix or a combination of matrix and conduit. If it represents a combination, the Manning–Strickler equation is used to calculate flow through the conduit. FEFLOW then determines the required hydraulic gradient and thus the head in the conduit necessary to produce the same flow using the porous media equation. The conduit itself is embedded in the finite element mesh as a one-dimensional feature, meaning it has no real diameter, only length. The adjustable parameters in the discrete feature portion of the model include friction coefficient and diameter or hydraulic radius.

6.4

RESULTS & CALIBRATION

The results of the model are expressed in terms of heads in the form of a potentiometric surface, spring fluxes, and velocities of flow in the conduits. 6.4.1 Spring Fluxes The model calibrated well to the St. Mark’s and Wakulla discharges, while it was low in comparison to the Spring Creek and Wacissa Group values. Further refinement of the model in terms of conduit size and friction factor will adjust the fluxes at the springs with values deviating more than one order or magnitude from their observed values. 6.4.2 Heads See Appendix VII for a table of modeled heads vs. observed heads. In general, modeled heads in the karst plain were very close to observed values, whereas there was greater deviation from observed under the confined section. The deviation in values under the confined section can mostly be attributed to lack of pumping in the model. Future instances of the model will likely include pumping in order to further refine the calibration.

Table 6-1. Modeled vs. observed spring fluxes. Modeled Spring

Magnitude

Calibration Flux (cfs)

Model Flux (cfs)

Wakulla

1

129

92.2

St. Marks Rise

1

452

502.4

Spring Creek Group

1

60*

0.8

1 1 2 2 2 2 2 2 2

293 > 100 > 100 10 to 100 10 to 100 10 to 100 10 to 100 10 to 100 10 to 100 10 to 100

58.0 23.7 26.6 1.2 1.3 0.9 0.6 1.6 1.2 0.8

Wacissa Group Wacissa #2 Big Blue Horsehead Garner Minnow Little Blue Cassidy Log Thomas * estimated

Figure 6-2 is a map of the potentiometric surface predicted for the entire WKP. There are several things to note there. One is that the gradient in the karst plain is flat. This is in keeping with a high conductivity material. Also, the gradients are steeper in the confined section; in keeping with a low conductivity material. The potentiometric surface on the western side of the basin has potentials that Hazlett-Kincaid, Inc.

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run nearly north-south. This compares favorably with published maps (Davis, 2007). Lastly, it should be noted that flow is in general attracted to the cave systems, which makes sense in that they represent some of the lowest heads in the system. Figures 6-3, 6-4, and 6-5 are detailed views of different parts of the basin and the corresponding potentiometric surface maps. Figure 6-3 shows the upper part of the central basin, with detailed views of the Leon Sinks cave system, the SESF pathway, and Wakulla Cave. Note that where it was necessary to add them to the model for calibration purposes, feeder conduits were emplaced. Such structures are evident on the northern end of the Leon Sinks cave system. In general, feeder conduits were placed in the model using the geological reasoning that they likely did not reach out further than the confined section, in the event that no sinking streams or the like were present in the confined section. From a flow perspective, the thing to note in Figure 6-3 is the ever-increasing convergence of flow as one follows the caves/conduits from north to south. Figure 4 details the potentiometric surface in the region between the southern end of the Wakulla cave system and Spring Creek. This is a pathway that has not been traced, but is known to exist, based on tide-discharge relationships between the coast and Wakulla Spring. The most interesting thing to note here is the southern most pathway that comes in on the western side. This is the Lost Creek cave system. Again, this has not yet been mapped or traced, but fits within our conceptual model of how this system behaves. Interestingly, one can see that flow converges on the upper end of the Lost Creek pathway, which one would expect to happen for a sinking stream. Conversely, as the conduit approaches the Spring Creek-Wakulla pathway, one can see that flow diverges from the conduit, indicating that the Spring Creek-Wakulla pathway is not suited to handle the amount of water coming in from Lost Creek. It is notable that the modeled flux for Spring Creek was low and that further refinement of the model may results in a larger flux at Spring Creek and also the ability for Lost Creek to fully discharge along this pathway. Lastly, Figure 6-5 shows a detailed view of the potentiometric in the upper Wacissa and St. Mark’s conduit systems. Wacissa is comprised of many smaller springs and therefore has a hypothesized ganglion network of conduits feeding them. The upper St. Mark’s reaches to the north to some large sinking streams, such as Paddy Sink. Again, flow converges on the conduit systems and the gradients are flattened near the conduits; imparting an effect similar to that of a zone of high conductivity in a porous media. In summary, we see that the effects of the conduits are to hasten flow to the springs, to flatten the surrounding gradient, and to converge flow on the conduits. All of these effects make for a model that is able to match spring flows and heads fairly well over the WKP, using a non-traditional approach that incorporates caves explicitly. 6.4.3 Conduit Velocities Another calibration criteria are the velocity of water flowing through the conduits. We have measured a range of these velocities using the groundwater tracing. The average linear velocities average on the order of hundreds to thousands of meters per day. Figures 6-6 through 6-8 are maps showing the conduit system used in the model and the velocities predicted by the model in the conduits. The key indicates the range of velocities present. In general, the model predicts lower velocities in the larger diameter sections of the cave system and higher velocities in the upper reaches of the caves networks, where the diameters would be expected to be much smaller. This is not a universal result, however, as model calibration in some instances dictated that parameters impacting flow velocities through the conduits (diameter and roughness coefficient).

6.5

DISCUSSION

6.5.1 Model Successes This effort represents the first of its kind to apply a combination of a multi-tracer approach and discrete element modeling to produce a basin-scale groundwater flow model through karst that is calibrated to heads, spring flows, and the velocity of flow through the conduits. The data and technologies brought Hazlett-Kincaid, Inc.

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to bear on this problem have made it an example that has taught us a lot about karst systems and how to better model and ultimately, manage them. 6.5.2 Efficacy of Numerical Modeling in Karst Our conceptual model approach has taught us that karst models must first be large (basin) scale in order to be successful and that the modeling can be accomplished with off-the-shelf tools. Smaller scale models can then follow on these models. Another necessity for successful karst modeling is that the models must be calibrated to spring flows first, followed by heads, and conduit velocities. Traditional models look to heads as first order calibration criteria. But in karst basins, if one doesn’t first calibrate to spring flows, one has no chance of getting the heads and velocities correct. It is also crucial that karst models have the conduits represented in them discretely. Experience has shown that computational expense and inaccurate velocities are the consequence of applying strictly porous media (MODFLOW) approaches to flow in karst versus a discrete finite element approach. Our modeling over the past two years has also shown that karst aquifers are not necessarily anisotropic, in a classical porous media sense. In order to define anisotropy, one must first define a Representative Equivalent Volume (REV), which is one of the fundamental difficulties when dealing in karst. Herein, we have successfully modeled flow in a karst basin while modeling large karst features discretely and assuming the rest of the domain to be a homogeneous, isotropic porous media. Lastly, in comparison to other tools used to study karst environments, such as age dating, our conceptual model approach stands apart. Age dating is a tool poorly applied in these environments because we know that spring fluxes represent a composite of water ages emanating from the spring. We have shown here that water must reach the spring in some instances on the order of days from the time it enters the cave system and although we did not demonstrate it explicitly, significant sinking streams in a basin are an indicator that age dating should not be applied, as possibly the majority of water coming from a spring (such as Wakulla) may be recently recharged surface water.

6.6

APPLICATIONS OF THE MODEL

The most immediate applications, beyond scenario testing, for the model as it currently stands are Minimum Flows and Levels (MFL’s) and Total Maximum Daily Loads (TMDL’s). MFL’s are a water quantity issue that speaks to a model’s ability to simulate spring flows successfully, as well as boundaries on the spring shed. Both of these capabilities are available in our current model. Also, since MFL’s are concerned with minimum flows and levels, the model is also in good standing, since the data set used to calibrate the model was a low water data set from 1991. Further impacts to the springs through large withdrawals in the basin could be easily evaluated. Total Maximum Daily Loads (TMDL’s) are the other straightforward impact analyses that could be performed with this model. TMDL’s are concerned with point and non-point source contamination of waters. It is our contention that the model would also be useful, with some slight modification, for evaluating these for at least the St. Mark’s and Wakulla Rivers. What these two have in common is that they both are spring-sourced rivers and a large volume of recently recharged surface water feeds them both. Contaminant transport scenarios that may have to be performed for TMDL calculations are based on a steady state flow field, which we have already established. If it was deemed necessary to move to transient, this could easily be done as well. Lastly, the model can be used as a decision support tool for development issues. The model would allow one to test the impacts of a given type, quantity, or duration of contamination or generalized impact on spring quantity or quality.

6.7

MODEL LIMITATIONS

There are several limitations on the current model. First, the model is steady state and is representative of a combination of mostly 1991 heads with a few 2006 heads - all collected from the USGS and the NWFWMD. The steady state condition is limiting in that only steady flow scenario can be explored, while the 1991 & 2006 data set is limiting in that they do not represent current conditions.


74


Another limitation is the selection of boundary conditions. Simulating flow through the Upper Floridan aquifer was the objective of the modeling, but particularly in the north, boundary conditions were not easily imposed. The northern boundary was eventually made to reflect heads predicted by another model (Davis, 1996). A solution to this limitation would be to have more data along the boundary that would allow for actual head values to be interpolated to the boundary. A second issue with the northern boundary is that there has been reported a flux in the Floridan from north to south which would have been entering our model domain. We did not consider this flux explicitly. A third limitation is that there is a lack of data on the hydraulic conductivity of the matrix. More pumping data is required to calibrate the heads in the model. We could further improve on it by building a bigger model, such that we could capture all of the area for all of the spring basins in the WKP. All of these improvements to the model could be made fairly easily. More difficult improvements to the model include: gauging hydrographs at the sinking streams and discharge measurements on Spring Creek, Wacissa, and St. Marks. All of these would really be necessary to move the model to a transient version with a defensible updated data set.

6.8

RECOMMENDATIONS AND CONCLUSIONS

We recommend that, in general, the model be further refined. This would first be accomplished by remeshing the domain, as our modeling has shown us that the mesh is too complicated and could benefit by simplification. This would cut computational time and allow for us to more easily add hypothesized or traced pathways. Next, we need to add a confining section, thereby modeling the materials north of the escarpment. The confining unit would simulate heads in the clays sand and limestone above the Floridan and would also contain the streams and rivers. Recharge would also be added to the new model over the unconfined section, with constant heads in the confined region. Lastly, pumping wells would be added. Modeling currently calibrated heads to heads in the unconfined WKP could perform further calibration with the current data. Spring fluxes need to be improved on, specifically and large increase is needed for the Spring Creek flux and a slight increase is needed for the Wakulla Spring flux. We need to greatly increase the Wacissa Spring Group flux. Velocities need overall improvement: the model Spring Creek velocities need to be increased, the Wacissa velocities need to be increased, while the St. Mark’s cave and Wakulla velocities need to be decreased. Lastly and probably most importantly, efforts need to be made to move the steady model toward a transient model and to engage in scenario analysis. To do this we will need to perform a data gap analysis, seek out additional time data sets, obtain more data on static heads, pumping heads, and pumping rates and finally, get stage and flux data on sinking streams, sinkholes, and springs, as relevant. The scenario analysis would entail moving the steady flow model into a transient transport model, where contaminant scenarios, such as nitrates from the SESF, could be investigated quantitatively. In a broader sense, we recommend that this approach of multiple tracers, combined with finite element modeling, be extended to other portions of the State where similar conditions persist. The area of high karstification, such as the WKP, extends eastward and southward, around the Big Bend of Florida, as approximately far south as Tampa. The use of this approach could lead to better land use strategies and more informed watershed management in sensitive groundwater areas statewide.


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6.9

FIGURES

Figure 6-1. Constant head boundary conditions are in blue, whereas the boundary is no flow everywhere else. The model area is shown superimposed on the potentiometric surface map from Davis 1996 to show how the boundaries were derived.


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Figure 6-2. Potentiometric surface map for the WKP model. Note the cave systems and inferred conduits in black.


77


Figure 6-3. Detailed potentiometric surface map showing flow convergence on Leon Sinks, the SESF pathway, and Wakulla cave system.


78


Figure 6-4. Detailed view of the potentiometric surface surrounding a hypothesized connection between the Wakulla cave system and Spring Creek. Lost Creek connects via the southernmost pathway coming in from the northwest.


79


Figure 6-5. Detailed potentiometric surface showing construed conduit systems and their impact on heads in the upper reaches of the St. Mark’s and Wacissa systems. The Wacissa is shown on the right.


80


Figure 6-6. Average linear velocities are shown along the conduit pathways in the model of the basin.


81


Figure 6-7. Detailed average linear velocity magnitude map.


82


Conduit Velocity (m/d)

Figure 6-8. Detailed average linear velocity map of the upper St. Mark's and the Wacissa conduit systems.


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7

TASK-5: EDUCATION AND OUTREACH

7.1


This task provided for the development and delivery of education and outreach programs designed to convey the data being collected by the WKP project endeavors to Florida residents and students, particularly those residing in Leon and Wakulla Counties. This task will also provide support for the organization and publication of the annual HC Workshop. Anticipated deliverables included: 

Development and delivery of a short course focused on karst in the WKP.



Public presentation on the karst hydrogeology of the WKP at the Wakulla Wildlife Festival.



Development of educational materials for the traveling exhibits and trailhead kiosks.

Development and support for the Annual Hydrogeology Consortium Workshop.

7.2

PROJECT STATUS

There was no Hydrogeology Consortium Workshop in 2006. HKI therefore directed our focus on the development of the karst short course and the presentation materials for traveling exhibits, specifically the Wakulla Wildlife Festival. The following summarizes the tasks performed. 

HKI developed a PowerPoint Presentation and reference manual covering theoretical and applied concepts of karst hydrogeology. The main sections of the presentation and reference manual include: o

Cave Formation - Chemistry & Kinetics of Karst Waters (9 papers)

o

Cave Formation – Conceptual Models for Cave Formation (9 papers)

o

Karst Monitoring (8 papers)

o

Geophysical & Remote Sensing Methods (7 papers)

o

Groundwater Tracers - Natural Tracers (4 papers)

o

Groundwater Tracers - Artificial Tracers (7 papers)

o

Karst Modeling (3 papers)



HKI prepared a preliminary field guide documenting a field trip in the WKP to be offered simultaneously with the short course.



HKI held a short course on April 27-28, 2006 in Tallahassee that included the WKP field trip. Appendix VIII provides a copy of the short course flyer and preliminary field guide. The course was attended by 33 people from varying backgrounds including: FGS, FDEP, City and County municipalities, water management districts, private consulting firms, and non-profit organizations.



HKI delivered copies of the Karst Short Course Reference Manual to FGS immediately after the April 2006 short course.



HKI developed and printed a presentation scale full-color map of the WKP at 1:35000. The map is not included with this report but can be delivered to FGS upon request. The map depicts and describes all of the key hydrologic features in the WKP including:



o

distribution and thickness of the confining unit,

o

orientation of all mapped underwater caves,

o

orientation of all traced groundwater flow pathways, and

o

the position of all major swallets and springs.

HKI developed and staffed an educational booth at the April 22, 2006 Wakulla Wildlife Festival that focused on describing the hydrogeology of the WKP, the significance of karst in the basin,


84


and the vulnerability of springs and groundwater resources to contamination. The WKP presentation map was part of the booth.

7.3

RECOMMENDED ACTIONS 

Refine the short course materials such that they include a specific syllabus and can be delivered to the students as stand alone educational materials.



Formalize the preliminary WKP Field Guide.



Develop a field guide and specific course materials for the Santa Fe River Basin such that course can be offered in central Florida.


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8

REFERENCES

Alexander, Calvin, and J. Quinlan, 1992, Practical Tracing of Groundwater, with Emphasis on Karst Terranes, A Short Course Manual presented on the occasion of the Annual Meeting of the Geological Society of America, 40 pp, Second Edition. Belcher, R.C. and Paradis, A., 1992, A mapping approach to three-dimensional modeling, in Turner, A. K., ed., Three-dimensional modeling with geoscientific information systems, NATO ASI Series C, Mathematical and Physical Sciences, v. 354, p. 107-122. Ceryak, R., 1981, Significance of the Cody Scarp on the hydrogeology of north central Florida in Karst hydrogeology and Miocene geology of the Upper Suwannee River basin, Hamilton County, Florida, Field Conference Guidebook, Southeastern Geological Society, Tallahassee, Florida, pp. 24-29. Chelette, A., Pratt, T. R., and Katz, B. G., 2002. Nitrate loading as an indicator of nonpoint source pollution in the lower S. Marks-Wakulla Rivers watershed: Water Resources Special Report 02-1, Northwest Florida Water Management District, Havana, Florida, 138 p. Crane, J.I., 1986. An Investigation of the Geology, Hydrogeology, and Hydrochemistry of the Lower Suwannee River Basin. Report of Investigation No. 96, Florida Geological Survey. Davis, H., 1996. Hydrogeologic Investigation and Simulation of Ground-Water Flow in the Upper Floridan Aquifer of North-Central Florida and Delineation of Contributing Areas for Selected City of Tallahassee, Florida, Water Supply Wells: USGS Water-Resources Investigation Report 95-4296. Davis, H., 2007. US Geological Survey. Personal Communication, Tallahassee Florida Diersch, H.-J. G., 2005, FEFLOW Finite Element Subsurface Flow & Transport Simulation System, Reference Manual. Florida Springs Conference, 2000. Natural Gems-Troubled Waters, Gainesville, Florida. http://palmm.fcla.edu/lfnh/related/springs.html Gerami, A., 1984. Hydrogeology of the St. Marks river basin, northwest Florida. M.S. Thesis, Florida State University, Tallahassee, Florida. Hazlett-Kincaid, 2004. On-going results and data from the Woodville Karst Plain collaborative research projects. Website accessed August 2006. http://www.hazlett-kincaid.com/FGS/ Hazlett-Kincaid, 2005. Woodville Karst Plain Research, Report of Investigations 2005. Report submitted to Florida State University and the Florida Geological Survey, Tallahassee Florida. Hendry, C.W. Jr., and Sproul, C.R., 1966. Geology and groundwater resources of Leon county, Florida, Bulletin No. 47, Florida Geological Survey, Tallahassee, Florida, 178 p. Hydrogeology Consortium, 2005, Solving Water Pollution Problems in the Wakulla Springshed of North Florida, May 12–13, 2005, Tallahassee, Florida. http://www.hazlett-kincaid.com/FGS/HC_Workshops/2005_WS_Workshop/index.htm Kincaid, T. R., 1999. Morphologic and Fractal Characterization of Saturated Karstic Caves, Ph.D. Dissertation, University of Wyoming, Laramie, 174 p. Kincaid, T. R., Davies, G. J., Hazlett, T. J., Loper, D., DeHan, R., and McKinlay, C., 2004, Groundbreaking characterization of the karstified Floridan aquifer in the Woodville Karst Plain of north Florida, Abstract No: 80391, GSA Abstracts with Programs Vol. 36, No. 5. Kincaid, T.R., Hazlett, T.J., and Davies, G.J., 2005, Quantitative groundwater tracing and effective numerical modeling in karst: an example from the Woodville Karst Plain of North Florida,: in Sinkholes and the Engineering and Environmental Impacts of Karst, Barry F. Beck ed., American Society of Civil Engineers, Reston, VA, p. 114-121. Lane, E., 1986. Karst in Florida: Special Publication No. 29, Florida Geological Survey, Tallahassee, Florida, 100 p.


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Loper, D.E., Werner, C.L., Chicken, E., Davies, G., and Kincaid, T., 2005a, Coastal Carbonate Aquifer Sensitivity to Tides, EOS, Transactions of the American Geophysical Union, vol. 86, no. 39. Loper, D.E., Landing, W. M., Pollman, C.D., Chan Hilton, A. B., 2005b, Degradation of Water Quality at Wakulla Springs, Florida: Assessment and Recommendations, Report of the Peer Review Committee on the Workshop Solving Water Pollution Problems in the Wakulla Springshed of North Florida, May 12–13, 2005, Tallahassee, Florida. Macesich, M. and Osmond, J.K., 1989, Uranium isotopic study of Wakulla Springs, Abstracts with Programs, Geological Society of America, vol. 21, no. 3, pp. 49. McKinlay, C.M., 2006, personal communication. Director: Woodville Karst Plain Project, High Springs, Florida, http://www.gue.com/Projects/WKPP/index.html NOAA, 2006. Tide Data for Apalachicola, Florida. Website accessed August 206. http://tidesandcurrents.noaa.gov/station_info.shtml?stn=8728690+Apalachicola+%2C+FL Paradis, A. and Belcher, R.C., 1990, Interactive volume modeling, a new product for 3-D mapping: Geobyte, v. 5, no. 1, pp. 42-44. Puri, H.S. and Vernon, R.O., 1964. Summary of the geology of Florida and a guidebook to the classic exposures. Florida Geological Survey Special Publication 5, 312 p. Rosenau, J.C., Faulkner, G.L., Hendry, C.W. Jr., and Hull, R.W., 1977. Springs of Florida, Bulletin No. 31 (revised), Florida Geological Survey, Tallahassee, Florida. Rupert, F., 1988. The geology of Wakulla springs, Open File Report No. 22, Florida Geological Survey, Tallahassee, Florida, 18 p. Schnegg, P.-A. and Kennedy, K., 1998. A new borehole fluorometer for double tracer tests. Mass Transport in Fractured Aquifers and Aquitards, Geoscience Center Copenhagen. Scott, T.M., Campbell, K.M., Rupert, F.R., Arthur, J.D., Missimer, T.M., Lloyd, J.M., Yon, J.W., and Duncan, J.G., 2001. Geologic Map of the State of Florida, Florida Geological Survey. http://sofia.usgs.gov/publications/maps/florida_geology/#sections/ Scott, T. M., Campbell, K. M., Rupert, F. R., Arthur, J. D., Missimer, T. M., Lloyd, J. M., Yon, J. W. and Duncan, J. G., 2001. Scale 1:750,000. Map Series No. 146, Florida Geological Survey, Tallahassee, Florida, 1 sheet. Scott, T. M., Means, G. H., Means, R. C., and Meegan, R. P.,2002. First Magnitude Springs of Florida, Open File Report NO. 85, Florida Geological Survey, Tallahassee, Florida. Smart, P., T. Atkinson, I. Laidlaw, M. Newson and S. Trudgill, 1986, Comparison of the results of Quantitative and Non-Quantitative Tracer Tests for Determination of Karst Conduit Networks: An Example from the Traligill Basin Scotland, Earth Surface Processes and Landforms, vol. 11, p. 249-261. Stone, W. C., 1989, The Wakulla Springs Project, U.S. Deep Cave Diving Team, Derwood, MD. Werner, C. L., 1998. Groundwater flow pattern analysis from cave exploration in the Woodville Karst Plain, Florida, Proceedings of the Wakulla springs Woodville Karst Plain symposium, October 9, 1998, Schmidt, W., Lloyd, J. and Collier, C., Eds., Florida Geological Survey Special Publications Series No. 46, pp. 37-43. Werner, C. L., 2001. Preferential Flow paths in Soluble Porous Media and Conduit System Development in Carbonates of the Woodville Karst Plain, Florida, M. S. Thesis, Florida State University. White, W.A., 1970. The Geomorphology of the Florida Peninsula. Geological Bulletin No. 51, Florida Geological Survey.


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