Lake County, Florida, 1990-99

Home , Lake Louisa State Park, Ocala National Forest

Ground-Water Quality of the Surficial Aquifer System and the Upper Floridan Aquifer, Ocala National Forest and Lake County, Florida, 1990-99

By James C. Adamski and Leel Knowles, Jr.

U.S. GEOLOGICAL SURVEY

Water-Resources Investigations Report 01–4008

Prepared in cooperation with the

Lake County Water Authority St. Johns River Water Management District Southwest Florida Water Management District

Tallahassee, Florida 2001 U.S. DEPARTMENT OF THE INTERIOR GALE A. NORTON, Secretary

U.S. GEOLOGICAL SURVEY Charles G. Groat, Director

The use of firm, trade, and brand names in this report is for identification purposes only and does not constitute endorsement by the U.S. Geological Survey.

For additional information write to: Copies of this report can be purchased from:

District Chief U.S. Geological Survey U.S. Geological Survey, WRD Branch of Information Services Suite 3015 Box 25286 227 North Bronough Street Denver, CO 80225-0286 Tallahassee, FL 32301 Phone: 1-800-ASK-USGS

Additional information about water resources in Florida is available on the World Wide Web at http://fl.water.usgs.gov CONTENTS

Abstract...... 1 Introduction ...... 2 Purpose and Scope...... 2 Previous Investigations...... 2 Acknowledgments ...... 4 Environmental Setting ...... 4 Physiography ...... 4 Hydrology and Hydrogeology...... 4 Land and Water Use...... 7 Data Collection and Analysis ...... 9 Ground-Water Quality ...... 13 Surficial Aquifer System ...... 13 Upper Floridan Aquifer ...... 21 Summary...... 31 References ...... 34 Appendix ...... 35

Figures 1. Map showing location of the Ocala National Forest and Lake County, Florida ...... 3 2. Map showing physiography of the study area...... 5 3. Chart showing geologic and hydrogeologic units in the study area...... 6 4-6. Maps showing: 4. Potentiometric surface of the Upper Floridan aquifer in the Ocala National Forest, Lake County, Florida, and vicinity, May 1998...... 8 5. Location of wells with water-quality data ...... 10 6. Location of springs including those with water-quality data...... 11 7. Plot showing relation of concentrations of total dissolved solids to specific conductance in ground-water samples from the surficial aquifer system and the Upper Floridan aquifer ...... 12 8-10. Maps showing: 8. Relative concentrations of calcium, magnesium, and sodium in samples from wells tapping the surficial aquifer system...... 14 9. Relative concentrations of bicarbonate, sulfate, and chloride in samples from wells tapping the surficial aquifer system...... 15 10. Concentrations of total dissolved solids in samples from wells tapping the surficial aquifer system...... 16 11-13. Boxplots showing: 11. Distribution of calcium, magnesium, sodium, and potassium in springs and in wells tapping the surficial aquifer system and the Upper Floridan aquifer ...... 17 12. Distribution of pH, bicarbonate, sulfate, and chloride in springs and in wells tapping the surficial aquifer system and the Upper Floridan aquifer ...... 18 13. Distribution of dissolved oxygen, nitrate, Kjeldahl nitrogen, and phosphate in springs and in wells tapping the surficial aquifer system and the Upper Floridan aquifer ...... 19 14. Map showing nitrate concentrations in samples from wells tapping the surficial aquifer system ...... 20 15. Plot showing relation of nitrate concentrations to pH in wells tapping the surficial aquifer system in Lake County, Florida ...... 21

Contents III 16-24. Maps showing: 16. Relative concentrations of calcium, magnesium, and sodium in samples from wells tapping the Upper Floridan aquifer ...... 22 17. Relative concentrations of bicarbonate, sulfate, and chloride in samples from wells tapping the Upper Floridan aquifer ...... 23 18. Concentrations of total dissolved solids in samples from wells tapping the Upper Floridan aquifer...... 24 19. Sulfate concentrations in samples from wells tapping the Upper Floridan aquifer ...... 25 20. Chloride concentrations in samples from wells tapping the Upper Floridan aquifer...... 26 21. Relative concentrations of calcium, magnesium, and sodium in samples from springs discharging from the Upper Floridan aquifer ...... 28 22. Relative concentrations of bicarbonate, sulfate, and chloride in samples from springs discharging from the Upper Floridan aquifer ...... 29 23. Concentrations of dissolved oxygen in samples from wells tapping the Upper Floridan aquifer ...... 30 24. Nitrate concentrations in samples from springs and from wells tapping the Upper Floridan aquifer ...... 32

Tables 1. Number of water-quality samples from wells and springs in the Ocala National Forest and Lake County, Florida ...... 9 2. Summary statistics of ground-water quality of the surficial aquifer system ...... 13 3. Summary statistics of ground-water quality from Upper Floridan aquifer springs and wells...... 27

CONVERSION FACTORS, VERTICAL DATUM, ABBREVIATIONS, AND ACRONYMS

Multiply By To obtain Length foot (ft) 0.3048 meter inch (in.) 25.4 millimeter Area square mile (mi2) 2.590 square kilometer (km2) Flow inch per year (in/yr) 25.4 millimeter per year million gallons per day (Mgal/d) 0.04381 cubic meter per second

Temperature in degrees Fahrenheit (°F) may be converted to degrees Celsius (°C) as follows: °C=(°F-32)/1.8.

Sea level: In this report, “sea level” refers to the National Geodetic Vertical Datum of 1929 (NGVD of 1929)--a geodetic datum derived from a general adjustment of the first-order level nets of both the United States and Canada, formerly called Sea Level Datum of 1929.

Acronyms and additional abbreviations: MCL Maximum Contaminant Level mg/L milligrams per liter IQR Inter Quartile Range NOAA National Oceanic and Atmospheric Administration NSDWR National Secondary Drinking Water Regulations Ocala NF Ocala National Forest RASA Regional Aquifer-System Analysis SJRWMD St. Johns River Water Management District TDS total dissolved solids USGS U.S. Geological Survey

IV Contents Ground-Water Quality of the Surficial Aquifer System and the Upper Floridan Aquifer, Ocala National Forest and Lake County, Florida, 1990-99

By James C. Adamski and Leel Knowles, Jr.

ABSTRACT aquifer system underlying the Ocala National Forest indicate that the aquifer is readily Data from 217 ground-water samples were recharged by precipitation and is susceptible to statistically analyzed to assess the water quality surface contamination. of the surficial aquifer system and Upper Flori- Concentrations of total dissolved solids dan aquifer in the Ocala National Forest and Lake were significantly greater in the Upper Floridan County, Florida. Samples were collected from aquifer (median was 182 milligrams per liter) than 49 wells tapping the surficial aquifer system, 141 wells tapping the Upper Floridan aquifer, and in the surficial aquifer system. In general, water from 27 springs that discharge water from the quality of the Upper Floridan aquifer was homo- Upper Floridan aquifer. A total of 136 samples geneous, primarily being a calcium or calcium- was collected by the U.S. Geological Survey magnesium-bicarbonate water type. Near the from 1995 through 1999. These data were St. Johns River, the water type of the Upper Flori- supplemented with 81 samples collected by the dan aquifer is sodium-chloride, corresponding to St. Johns River Water Management District and an increase in total dissolved solids. Dissolved- Lake County Water Resources Management from oxygen concentrations in the Upper Floridan 1990 through 1998. aquifer ranged from less than 0.1 to 7.3 milli- In general, the surficial aquifer system has grams per liter, indicating that, in parts of the low concentrations of total dissolved solids aquifer, ground water is rapidly recharged by rain- (median was 41 milligrams per liter) and major fall and is susceptible to surface contamination. ions. Water quality of the surficial aquifer system, Median concentrations of nutrients in the however, is not homogeneous throughout the Upper Floridan aquifer were not significantly study area. Concentrations of total dissolved different between the Ocala National Forest and solids, many major ions, and nutrients are greater the area of Lake County outside the Forest. The in samples from Lake County outside the Ocala maximum nitrate concentration in the Upper National Forest than in samples from within the Floridan aquifer in Ocala National Forest was only Forest. These results indicate that the surficial 0.20 milligram per liter, whereas, 9 of 39 samples aquifer system in Lake County outside the Ocala from the Upper Floridan aquifer in Lake County National Forest probably is being affected by had elevated nitrate concentrations (greater than agricultural and (or) urban land-use practices. 1.0 milligram per liter). Hence, nitrate concentra- High concentrations of dissolved oxygen (less tions of the Upper Floridan aquifer appear to be than 0.1 to 8.2 milligrams per liter) in the surficial affected by land use in Lake County.

Abstract 1 INTRODUCTION Lake County is about 1,150 mi2 in area. North- eastern Lake County overlaps with the Ocala NF. The Ground water is an important resource in central rest of Lake County is directly south of the Ocala NF Florida. Ground water from the Floridan aquifer sys- (fig. 1). Lake County is directly west and northwest of tem, particularly the Upper Floridan aquifer, is used metropolitan Orlando. extensively as a source of drinking water. Ground water, which discharges to lakes, springs, and streams Purpose and Scope throughout central Florida, also is used for agricultural, commercial, and industrial purposes. Hence, the qual- The purpose of this report is to describe the ground-water quality of the Ocala NF and Lake County ity of ground water is important for its numerous uses with regard to concentrations of major ions and nutri- and for the aquatic environment of central Florida. ents. The report contains a brief description of the The ground water underlying large areas of central environmental setting of the study area, including Florida, however, had not been studied recently. The climate, physiography, hydrogeology, and major land most recent comprehensive hydrologic study of Lake uses. The report also contains a description of data- County was published by Knochenmus and Hughes in collection and analytical methods. A discussion of the 1976. Because of recent growth in population, a compre- natural and anthropogenic factors affecting water qual- hensive study of Lake County was needed to assess the ity of the surficial aquifer system and the Upper Flori- current conditions of ground-water quality and to better dan aquifer is included. This report is the result of two understand the effects of land use on ground-water qual- comprehensive studies of the water resources of Ocala ity. A comprehensive hydrologic study of the Ocala NF and Lake County, Florida. National Forest (Ocala NF) was needed to document Previous Investigations water quality in a relatively pristine area. This report is the compilation of results from two comprehensive Fenneman (1938) described the topographic investigations of the hydrology of the Ocala NF and the and geomorphic features of Florida. Cooke (1945) hydrology of Lake County. The objectives for this part of described the geomorphology, geology, and stratigra- the two studies are to (1) describe current conditions of phy of Florida, and White (1970) further described the the ground-water quality of the Ocala NF and Lake geomorphology of the Florida peninsula. Matson and Sanford (1913) and Stringfield (1933 and 1936) were County and (2) determine the natural and anthropogenic the first to investigate the hydrogeology of Florida. factors affecting ground-water quality. Rosenau and others (1977) described the location, The study area is in north-central Florida and discharge, and water quality of numerous springs. includes all of Lake County and parts of Marion and Put- Later hydrogeologic investigations included the nam Counties that lie within the Ocala NF (fig. 1). The Regional Aquifer-System Analysis (RASA) of the study area includes numerous growing towns and com- Floridan aquifer system, in which the hydrogeologic munities including Clermont, Eustis, Tavares, Leesburg, framework of the Floridan aquifer system was Mount Dora, and Lady Lake in Lake County; and the described by Miller (1986). Tibbals (1990) simulated communities of Lynne, Salt Springs, and Astor Park, the ground-water flow in the Floridan aquifer system in which lie within the Proclamation Boundary (perimeter) east-central Florida using a model area that included of the Ocala NF. Agriculture, including citrus farming, most of the Ocala NF and Lake County. nurseries (horticulture), and livestock, is an important Sprinkle (1989) described the geochemistry of land use in the study area, excluding the Ocala NF. the Floridan aquifer system. Katz (1992) investigated 2 the geochemistry of the Upper Floridan aquifer The Ocala NF is about 690 square miles (mi ) of throughout the State of Florida. Rutledge (1987) and relatively pristine second-growth forests. The Ocala NF, German (1997) investigated the relation of land use and owned and operated by the U.S. Forest Service, has a ground-water quality. German (1997) compared sparse population and little anticipated population ground-water quality underlying areas of agricultural growth. Ground-water quality of the Ocala NF was not and urban land use in parts of Lake and Orange Coun- extensively studied prior to the current investigation. ties to ground-water quality underlying parts of the A comprehensive study of the Ocala NF was needed to Ocala NF. Toth (1999) investigated the geochemistry describe the natural conditions of the ground-water and isotopic composition of selected springs in the quality of central Florida. Ocala NF and Lake County.

2 Ground-Water Quality of the Surficial Aquifer System and the Upper Floridan Aquifer, Ocala National Forest and Lake County, Florida, 1990-99 Figure 1. Location of the Ocala National Forest and Lake County, Florida.

Introduction 3 Faulkner (1973) described the hydrogeology of Physiography northwestern Ocala NF during a study for the cross- Florida barge canal. Phelps (1994) investigated the Land-surface elevations in the Ocala NF and hydrogeology and water quality of the Silver Springs Lake County range from less than 10 feet (ft) to more basin, just west of Ocala NF. Knowles (1996) esti- than 300 ft above sea level. The highest point in the mated evapotranspiration of the Silver Springs basin. Florida peninsula (312 ft) is located on the north end Knochenmus and Hughes (1976) investigated ground of the Lake Wales Ridge in Lake County (fig. 2) water, surface water, and water quality of Lake County. (Knochenmus and Hughes, 1976). Topography of Murray and Halford (1996) simulated ground-water the study area ranges from flat-lying lands to gently flow in parts of Lake County. Few other studies of rolling hills. the water resources of the Ocala NF or Lake County are available. The study area is located in the Central High- lands topographic division (Cooke, 1945) and contains three basic land forms—ridges, valleys, and uplands Acknowledgments (fig. 2). Parts of the Mount Dora and the Lake Wales Ridges are located in the study area. These ridges, The authors are grateful to the St. Johns River Water Management District, Southwest Florida Water which are quasi-linear features, are a series of gently Management District, and Lake County Board of Com- rolling hills that trend northwest-southeast with eleva- missioners for information and hydrologic data made tions ranging from 100 to more than 300 ft above sea available for this investigation. Personnel at the U.S. level. The two ridges are parallel and separated by the Forest Service assisted with site access, data collection, Central Valley, an area of relatively low relief and land- and information. Finally, the authors are grateful to surface elevations (White, 1970). In addition to the land and well owners for access to sites. Central Valley, the St. Johns and Wekiva River valleys form the eastern boundary of the study area (fig. 1). The Lake Upland and Marion Upland areas present in ENVIRONMENTAL SETTING the study area contain gently rolling hills with elevations ranging from 50 to 200 ft. above sea level (White, The study area has a subtropical climate charac- 1970; Knochenmus and Hughes, 1976). terized by hot humid summers and mild winters. The mean annual air temperature is 70.7 degrees Fahren- In addition to these major land forms, numerous heit (oF) (National Oceanic and Atmospheric Admin- karst features including sinkholes, springs, and caves istration (NOAA), 1992). Minimum air temperatures are present in the study area. Sinkholes are abundant during the winter months occasionally drop below along the flanks of the ridges and uplands of the study freezing, but rarely are less than 20 oF. Maximum air area. Sinkholes can be dry or water-filled internally temperatures during the summer months are com- drained depressions that commonly are areas of high monly greater than 90 oF, and occasionally exceed recharge to the underlying aquifers. 100 oF locally. Average precipitation (from 1961 to 1990) ranges from about 52 inches per year (in/yr) in Ocala Hydrology and Hydrogeology to less than 51 in/yr in Clermont (NOAA, 1992). The average precipitation for the entire study area is slightly Surface-water resources are abundant through- more than 51 in/yr. Annual precipitation can vary out most of the study area. Except for the southwestern greatly from the average, ranging from a minimum of corner of Lake County, most of the study area is 32 inches (in.) in 2000 to a maximum of 71 in. in 1964. drained by the St. Johns River and its tributaries. The Typically, more than half of the precipitation occurs St. Johns and Wekiva Rivers form the eastern bound- during the summer as isolated thunderstorms and from aries of Lake County and the Ocala NF. The Ockla- tropical systems. The remainder of the precipitation generally occurs during winter months from frontal waha River forms the northwestern part of the systems. A large part of precipitation is balanced by Proclamation Boundary of the Ocala NF. Smaller evapotranspiration. For example, in 1998, precipitation tributaries discharge surface and ground-water to the in the study area was about 57 in., about 35 in. of which St. Johns and Wekiva Rivers. These tributaries include were balanced by evapotranspiration. Alexander Springs Creek and Blackwater Creek.

4 Ground-Water Quality of the Surficial Aquifer System and the Upper Floridan Aquifer, Ocala National Forest and Lake County, Florida, 1990-99 Figure 2. Physiography of the study area (modified from White, 1970).

Environmental Setting 5 Springs, which represent locations of ground- Lithologic descriptions of well cuttings, bore- water discharge, are abundant, and possibly located hole geophysical logs, and well completion reports along subsurface fracture systems of the Ocala Uplift were analyzed to describe the extent, thickness, and (Faulkner, 1973). Most springs are located along or lithology of the major hydrogeologic units in the study near the Ocklawaha, St. Johns, and Wekiva Rivers. area. These hydrogeologic units include the surficial A few small springs are located in central Lake and Floridan aquifer systems (fig. 3). County. Silver Springs is located just west of the study The surficial aquifer system consists of uncon- area, near the city of Ocala. Some of the larger springs, solidated, siliclastic sediments of Pliocene through such as Alexander, Salt, and Silver Glen, issue from Recent age. The sediments are primarily quartz sand, visible cavities or conduits formed from dissolution of but locally, the aquifer also contains silt, clay, chert, the carbonate rock. shell, or organic deposits that range in thickness from In addition to streams and springs, the study area less than 25 to more than 100 ft. In general, these is characterized by abundant lakes. These lakes range sediments are thicker under the Mount Dora and Lake in size from small, water-filled sinkholes and depres- Wales Ridges than under adjacent areas. sions to large water bodies such as Lake Eustis, Lake Griffin, and Lake Harris in Lake County, and Lake The surficial aquifer system is recharged prima- Dorr and Lake Kerr in the Ocala NF (fig. 1). Further- rily by precipitation. Ground water in the surficial more, Lake Apopka and Lake George are present on aquifer system flows laterally to discharge into streams the eastern boundaries of Lake County and the Ocala and lakes, and vertically to recharge the underlying NF, respectively. Upper Floridan aquifer. The elevation of the water Wetlands also are abundant in the study area. table in the surficial aquifer system ranges from near Wetlands are present along major streams and the perim- sea level along the St. Johns River to more than 165 ft eters of the lakes. The Green Swamp is a wetland area above sea level in areas underlying the Mount Dora that covers a large part of southern Lake County (fig. 1). Ridge. The elevation of the water table in the surficial Much of the Mount Dora Ridge in the Ocala NF aquifer system can fluctuate greatly within a short is drained internally through sinkholes and depres- time, particularly in areas of higher elevation. For sions. Streams are noticeably absent from the area. example, the water-table elevation in one surficial well Runoff in this area probably is minimal, with most of located in the northern part of the Ocala NF (number the precipitation being balanced by evapotranspiration 401 in appendix) increased more than 8 ft from and ground-water recharge. September 1997 to May 1998.

Figure 3. Geologic and hydrogeologic units in the study area (modified from Tibbals, 1990).

6 Ground-Water Quality of the Surficial Aquifer System and the Upper Floridan Aquifer, Ocala National Forest and Lake County, Florida, 1990-99 The Floridan aquifer system is separated from aquifer is within 25 ft of land surface. Hence, in these the overlying surficial aquifer system by the interme- areas, recharge probably occurs rapidly from precipi- diate confining unit (fig. 3). The intermediate confin- tation, which could allow the aquifer to be susceptible ing unit consists primarily of clay, silt, and carbonate to surface contamination. units of Miocene age, but can include clay units of Water levels in the Upper Floridan aquifer range Pliocene through Pleistocene age where these younger from near sea level in the St. Johns River basin to more units are vertically continuous. Thickness of the inter- than 100 ft above sea level in southern Lake County. mediate confining unit ranges from less than 20 ft to Ground water generally flows northward in southern more than 100 ft. Lake County, and northeastward elsewhere in the The Floridan aquifer system consists of a thick study area (Sepulveda, 1997; Merritt, 1998; Adamski, sequence of carbonate rocks of Eocene age (fig. 3) that 1998). In the Ocala NF, ground-water flow generally is divided into the Upper Floridan and Lower Floridan is from the west and southwest toward Lake George aquifers (Tibbals, 1990). This study focused primarily (fig. 4). Discharge from the Upper Floridan aquifer on water quality in the Upper Floridan aquifer because occurs in areas where the potentiometric surface is (1) the Upper Floridan aquifer is the primary source of higher than the water table of the surficial aquifer- drinking water in the area, (2) the Upper Floridan aqui- system—at springs, from flowing wells, and by slow fer is more susceptible to contamination than the Lower leakage through the intermediate confining unit into Floridan aquifer, and (3) data available for the Lower the surficial aquifer system. Floridan aquifer are sparse. The depth to the top of the Ocala Limestone, Land and Water Use which generally coincides with the top of the Upper Floridan aquifer, averages from less than 100 ft to more Land use in the Ocala NF primarily consists of than 200 ft throughout most of the study area (Tibbals, relatively pristine forests and wetlands that are desig- 1990). Just west of the study area, near the city of Ocala nated as multi-use lands and managed for recreational and along parts of the Ocklawaha River upstream of use and silviculture. In 1994, second-growth pine and Lake Ocklawaha, the Ocala Limestone is exposed at hardwood forests accounted for 65 percent, and water land surface; in areas of northeast Lake County, and and wetlands accounted for 19 percent of the land use near Lake George, the Ocala Limestone is within 50 ft (Agustin Sepulveda, U.S. Geological Survey (USGS), of land surface. written commun., 2000). A U.S. Naval bombing range Locally, the range of depth to the top of the occupies an area of about 9 mi2 in the south-central Upper Floridan aquifer can be large. Information from part of the Ocala NF (fig. 1), and is not open to the geologic and geophysical well logs indicate that the general public. depth to the top of the Upper Floridan aquifer can Land use within the Ocala NF Proclamation range several hundred feet over relatively small (less Boundary ranges from wilderness to residential. Land than a mile) spatial distances. The top of the Upper administered by the U.S. Forest Service covers about Floridan aquifer probably is rather hummocky as a 89 percent of the area contained by the Proclamation result of dissolution of the carbonate rocks. Although Boundary. Of the land owned by the U.S. Forest Ser- many of these dissolution features are buried by clastic vice, more than 71 percent is used for timber manage- deposits in a type of terrain known as mantled karst, ment/harvest, about 7 percent for wilderness, about sinkholes, springs, and caves present in parts of the 1 percent for U.S. Navy bombing practices, less than study area result from, and are indicative of, carbonate- 1 percent for recreational sites, and about 20 percent is rock dissolution. used as transportation corridors and access roads The Upper Floridan aquifer is recharged prima- (2,300 miles) (Richard B. Shellfer, U.S. Forest Service, rily by downward leakage from the surficial aquifer oral commun., 1999). Several communities (Astor, system through the intermediate confining unit. This Astor Park, Lynne, Paisley, and Salt Springs) are recharge can be rapid in places with abundant sink- located along or within the Proclamation Boundary of holes or where the intermediate confining unit is thin the Ocala NF and account for about 11 percent of the or breached by collapse into underlying dissolution land is private residential. Although mining currently is cavities. Just west of the study area, near the city of not practiced in the Ocala NF, a few small claypits are Ocala and in Sumter County, the Upper Floridan used for road maintenance within the forest area.

Environmental Setting 7 Figure 4. Potentiometric surface of the Upper Floridan aquifer in the Ocala National Forest, Lake County, Florida, and vicinity, May 1998 (modified from Adamski, 1998).

8 Ground-Water Quality of the Surficial Aquifer System and the Upper Floridan Aquifer, Ocala National Forest and Lake County, Florida, 1990-99 Land use in Lake County is a mixture of agricul- area. The assessment included collection of water- ture, forests, rangeland, urban, open water, and wet- quality samples, compilation of existing data, and lands. The percentages of these land uses, however, statistical analysis of the final data set. have changed over time. For example, agriculture Water-quality samples were collected by the (predominantly citrus) was about 43 percent of the land USGS from 1995 through 1999. Samples were col- use in 1977, but was less than 30 percent of the land use in 1994. The decrease in agriculture during this period lected from wells and springs located in the Ocala NF was related to several severe winter freezes, which had and (or) Lake County; locations are shown in figures 5 adverse effects on the citrus industry. Other types of and 6, respectively. The number of samples collected land use increased from 1977 to 1994 as a result of the in the forest and county areas and where these two decrease in agricultural land use (Agustin Sepulveda, areas overlap is listed in table 1. A total of 23 samples USGS, written commun., 2000). For example, forest were collected from wells in the surficial aquifer sys- increased from 15 percent to 18 percent, rangeland tem, 25 samples were collected from springs, and from 2 to 7 percent, and urban from 4 to 6 percent. 88 samples came from wells in the Upper Floridan Urbanization of Lake County has been rapidly increasing in recent years. Population of Lake County has aquifer (figs. 5 and 6, table 1, appendix). increased from 86,720 in 1975 to an estimated popula- Existing data were compiled from samples tion of 206,500 in 2000 (Richard L. Marella, USGS, collected by the SJRWMD and the Lake County Water written commun., 2000). Hence, present (2000) urban Resources Management. These samples were collected land use in Lake County probably is greater than 6 per- from wells and springs located in the Ocala NF and (or) cent. Water and wetlands have remained constant since Lake County, and are shown in figures 5 and 6, respec- 1977 at nearly 36 percent of the land use (Agustin tively. A total of 26 samples were collected from wells Sepulveda, USGS, written commun., 2000). in the surficial aquifer system (fig. 5, table 1). Two sam- Nearly all water withdrawn from the Ocala NF is ples were collected from springs (fig. 6) and 53 samples from the Upper Floridan aquifer and is used for domes- from wells in the Upper Floridan aquifer (fig. 5, table 1, tic and recreation use. Numerous private residences are distributed within the Proclamation Boundary of the appendix). The samples analyzed and evaluated for this Ocala NF. In 1998, residences and recreation sites used study were collected after 1990; samples collected prior nearly 2 million gallons per day (Mgal/d) of ground to 1990 were not considered representative of current water and returned about 60 percent to the ground-water ground-water conditions, especially outside the rela- system by septic systems (Richard Marella, USGS, tively undeveloped Ocala NF. written commun., 2000; Brian McGurk, St. Johns River Water Management District (SJRWMD), written Table 1. Number of water-quality samples from wells and commun., 1999). springs in the Ocala National Forest and Lake County, Lake County obtains most of its water from the Florida Upper Floridan aquifer. In 1998, Lake County pumped [USGS, U.S. Geological Survey; SJRWMD, St. Johns River Water Management District; Ocala NF, Ocala National Forest (outside of Lake more than 100 Mgal/d. Agricultural land use accounts County); Lake, Lake County (outside of Ocala National Forest); Overlap, for more than 50 percent; municipal, domestic, and area of Ocala National Forest within Lake County] recreation use accounts for nearly 40 percent; and com- Collecting Aquifer and Ocala Over- mercial/industrial use accounts for less than 10 percent Lake Total agency site type NF lap of the total water pumped. Currently, about 40 percent of all water pumped from the Upper Floridan aquifer in USGS Surficial aquifer 17 1 5 23 Lake County is estimated to be returned to the ground- (1995-99) system, wells water system by land application and by septic systems Upper Floridan 26 48 14 88 aquifer, wells (Richard Marella, USGS, written commun., 2000; Upper Floridan 815225 Brian McGurk, SJRWMD, written commun., 1999). aquifer, springs

SJRWMD Surficial aquifer 420226 DATA COLLECTION AND ANALYSIS and Lake system, wells County Upper Floridan 13 29 11 53 Water-quality data from springs and wells in (1990-98) aquifer, wells Ocala NF and Lake County were compiled to assess Upper Floridan 0112 current ground-water quality conditions in the study aquifer, springs

Data Collection and Analysis 9 Figure 5. Location of wells with water-quality data.

10 Ground-Water Quality of the Surficial Aquifer System and the Upper Floridan Aquifer, Ocala National Forest and Lake County, Florida, 1990-99 Figure 6. Location of springs including those with water-quality data.

Data Collection and Analysis 11 Water samples from wells were collected by the Simple linear regression indicated that total dis- USGS using either an existing submersible pump or a solved solids (TDS) concentrations of samples from portable 2-inch diameter stainless steel submersible both aquifers were significantly correlated to specific pump with silicone tubing. Field measurements of tem- conductance (r2>0.99) (fig. 7). If TDS concentrations perature, pH, and specific conductance were made on were not available, TDS was calculated as a function ground-water samples at all sites. Dissolved oxygen of specific conductance using the following equation: also was measured in the field. Samples were collected after purging the well of at least three casing volumes TDS = -27 + 0.65(specific conductance). and (or) after stabilization of the field measurements. Samples from springs were collected from inside the Results plotted in figure 7 illustrate that the correlation orifice either with sample bottles or a churn splitter and was not as good for samples with specific conductance processed using a peristaltic pump with silicone tubing. less than 100 microsiemens per centimeter. Samples were filtered using a 0.45-micrometer pore- The non-parametric Kruskal-Wallis test was size disposable capsule filter. All samples were ana- used to statistically identify differences in water qual- lyzed for major ions (calcium, magnesium, sodium, ity between the aquifers, between site types (springs potassium, sulfate, and chloride), alkalinity, and total and wells), and between geographic locations (Helsel dissolved solids; bicarbonate concentrations were cal- and Hirsch, 1992). For statistical purposes, samples culated from alkalinity. Samples for cation analysis from sites located in the area of overlap between the were acidified with nitric acid to adjust the pH to less Ocala NF and Lake County (table 1) were grouped than 2. Samples for nutrient analysis [nitrite plus nitrate with sites in the Ocala NF because land use in this area of northern Lake County is similar to the rest of the as nitrogen (hereafter referred to as “nitrate” because Ocala NF. Medians of groups of data are assumed nitrite generally was below detection limits), Kjeldahl significantly different from one another if the proba- nitrogen (ammonia plus organic nitrogen as nitrogen), bility (p-value) is less than 5 percent (<0.05) that the and phosphate] were chilled and delivered overnight to difference occurs by chance. The non-parametric the USGS laboratory in Ocala, Florida. Spearman’s rho (r) rank correlation coefficient was Some sites were sampled more than once over a used to determine monotonic relations between water- period of several years. Only the most recent, analyti- quality variables. cally complete sample was included in this study. The resulting data set (USGS and SJRWMD data) includes samples collected over a period of nearly 10 years using various methods and techniques. For example, some samples apparently were not filtered prior to analysis. Laboratory-measured pH and alkalinity were used if field-measured pH and alkalinity were not available. In addition, many of the 217 samples were incomplete with respect to major-ion analyses. Cal- cium, magnesium, and sodium concentrations were available for only 174 samples, bicarbonate concentrations were available for only 145 samples, chloride concentrations were available for 203 samples, and sulfate concentrations were available for 199 samples. Nitrate concentrations were available for 98 samples, Kjeldahl nitrogen concentrations were available for 81 samples, and phosphate concentrations were avail- Figure 7. Relation of concentrations of total dissolved solids able for 71 samples. Data used in this report are shown to specific conductance in ground-water samples from the in the appendix. surficial aquifer system and the Upper Floridan aquifer.

12 Ground-Water Quality of the Surficial Aquifer System and the Upper Floridan Aquifer, Ocala National Forest and Lake County, Florida, 1990-99 GROUND-WATER QUALITY Drinking Water Regulations (NSDWR) for TDS (500 mg/L), chloride (250 mg/L), or sulfate (250 mg/L). The Ocala NF is a relatively pristine area. Hence, NSDWRs are non-enforceable drinking water standards the ground-water quality conditions of the Ocala NF issued for taste or aesthetic purposes (U.S. Environmen- probably approximate the natural ground-water quality tal Protection Agency, 2000). Water in the surficial aqui- of north-central Florida. As noted, the land use of Lake fer system is slightly acidic, with a pH of 6.1 or less in County is primarily a mixture of agriculture, forest, and 50 percent of the samples (table 2). Three samples had a rangeland with increasing urbanization. The compila- pH of 4.5 or less. Furthermore, pH was significantly tion of data from these two areas allows for the compar- correlated to concentrations of TDS (r = 0.64). In 18 of ison of water quality with respect to land use. 19 samples with pH less than or equal to 6.0, TDS concentrations were less than or equal to 60 mg/L. Surficial Aquifer System The median TDS concentrations in the surficial aquifer system is significantly greater (p = 0.01) in Ground water in the surficial aquifer system samples from Lake County (96 mg/L) than in samples generally has low concentrations of major ions and total from the Ocala NF (36 mg/L). In addition, median pH dissolved solids. The water type of the surficial aquifer and concentrations of calcium, magnesium, potas- system is laterally diverse; results indicate that in places sium, bicarbonate, and sulfate in the surficial aquifer the ground water in the surficial aquifer can be calcium system are significantly greater (p<0.01, <0.01, bicarbonate, sodium-chloride, or mixed cation and <0.01, <0.01, <0.01, and 0.04, respectively) in sam- mixed anion (figs. 8 and 9). TDS concentrations of ples from Lake County than in samples from the all samples ranged from 3 to 356 milligrams per liter Ocala NF (figs. 11 and 12). pH and concentrations of (mg/L), with a median of 41 mg/L (table 2, fig. 10). sulfate, chloride, and total dissolved solids (fig. 10) in More than 75 percent of the samples had TDS concen- the surficial aquifer system are lowest in the central trations less than 100 mg/L. None of the samples had part of the Ocala NF and increase toward the St. Johns concentrations that exceeded the National Secondary and Ocklawaha Rivers.

Table 2. Summary statistics of ground-water quality of the surficial aquifer system [µS/cm, microsiemens per centimeter; °C, degrees celsius; mg/L, milligrams per liter; N, nitrogen; P, phosphorus; <, less than; --, missing information]

Lake County Ocala National Forest

Constituent Units Number Number of Minimum Median Maximum of Minimum Median Maximum samples samples Specific conductance µS/cm 19 47 190 590 26 25 52 496 pH standard 15 5.0 6.4 7.9 26 4.4 5.8 8.8 units Temperature °C 21 20.0 23.8 25.5 26 21.6 23.1 26.1 Dissolved oxygen mg/L 0 ------11 <0.1 5.5 8.2 Calcium mg/L 20 3 14 91 25 <1 2 28 Magnesium mg/L 20 0.6 4.7 21 25 <.1 0.9 4.1 Sodium mg/L 20 1.9 6.0 48 25 .7 4.4 93 Potassium mg/L 20 .21 1.7 9.7 24 <.1 .25 5.3 Bicarbonate mg/L 7 17 27 164 21 4 11 85 Sulfate mg/L 16 .2 6.7 52 27 .1 3 64 Chloride mg/L 16 2.9 7.8 24 27 1 7 42 Fluoride mg/L 14 <.1 0.1 1.7 25 <.1 <.1 0.6 Dissolved solids, total mg/L 18 4 96 356 26 3 36 294 Nitrite plus nitrate mg/L as N 10 .02 .07 4.2 15 <.02 .1 1.6 Kjeldahl nitrogen mg/L as N 8 .21 .28 1.0 12 <.2 .24 .88 Phosphate mg/L as P 2 .06 .1 0.14 12 .01 .04 .96

Ground-Water Quality 13 Figure 8. Relative concentrations of calcium, magnesium, and sodium in samples from wells tapping the surficial aquifer system.

14 Ground-Water Quality of the Surficial Aquifer System and the Upper Floridan Aquifer, Ocala National Forest and Lake County, Florida, 1990-99 Figure 9. Relative concentrations of bicarbonate, sulfate, and chloride in samples from wells tapping the surficial aquifer system.

Ground-Water Quality 15 Figure 10. Concentrations of total dissolved solids in samples from wells tapping the surficial aquifer system.

16 Ground-Water Quality of the Surficial Aquifer System and the Upper Floridan Aquifer, Ocala National Forest and Lake County, Florida, 1990-99 Dissolved oxygen is abundant in the surficial 10 mg/L (U.S. Environmental Protection Agency, aquifer system underlying the Ocala NF. Nine samples 2000). Nitrogen constituents (nitrate and Kjeldahl had dissolved-oxygen concentrations ranging from 3.1 nitrogen) were detected in 67 percent of the samples. to 8.2 mg/L; only two samples had dissolved-oxygen The low median concentration probably is a result of concentrations less than 0.1 mg/L. Dissolved-oxygen the pristine, relatively undeveloped conditions in the data were not available for any samples collected from area. Nitrate and Kjeldahl nitrogen were detected at Lake County. higher concentrations and more frequently in the surfi- Concentrations of nutrients in the surficial aqui- cial aquifer system in Lake County than in the Ocala fer system generally are low. Nitrate concentrations in NF. Nitrate concentrations in Lake County range from samples from the Ocala NF range from less than 0.02 less than 0.02 to 4.2 mg/L, with a median of 0.07 mg/L to 1.6 mg/L with a median of 0.1 mg/L (table 2, fig. 13). (figs. 13 and 14). Nitrate was detected in nearly None of the samples had nitrate concentrations that 80 percent of the samples, and Kjeldahl nitrogen was exceeded the Maximum Contaminant Level (MCL) of detected in 75 percent of the samples.

Figure 11. Distribution of calcium, magnesium, sodium, and potassium in springs and in wells tapping the surficial aquifer system and the Upper Floridan aquifer.

Ground-Water Quality 17 Figure 12. Distribution of pH, bicarbonate, sulfate, and chloride in springs and in wells tapping the surficial aquifer system and the Upper Floridan aquifer.

Phosphate was greater than or equal to 0.02 mg/L (pH ranging from about 4.5 to 5.0 in 1999) with in more than 85 percent of the samples. The source of concentrations of major ions generally less than 1 mg/L. phosphate in the aquifer could be anthropogenic or nat- For example, in 1999 calcium concentrations in rainfall ural phosphatic sands in the surficial aquifer system and ranged from 0.08 to 0.25 mg/L, sodium concentrations underlying Hawthorn Formation. ranged from 0.14 to 0.33 mg/L, and chloride concentra- The water quality of the surficial aquifer system tions ranged from 0.26 to 0.58 mg/L (National Atmo- likely can be attributed to a number of factors including spheric Deposition Program, 2000). These ions are rainfall quality, the lithology of the aquifer, mixing of concentrated in the aquifer through evapotranspiration water from the surficial aquifer system with water dis- processes. The low pH and TDS of most samples in the charging or leaking from the Upper Floridan aquifer, Ocala NF indicate that the quartz-sand lithology of the and effects of land use. Low concentrations of dis- surficial aquifer system is unreactive and does not solved solids (less than 100 mg/L) probably originate significantly affect the geochemistry of the ground in precipitation recharging the aquifer. Precipitation water. As previously noted, the surficial aquifer system chemistry in peninsular Florida generally is acidic in Lake County can contain clay and shell units that can

18 Ground-Water Quality of the Surficial Aquifer System and the Upper Floridan Aquifer, Ocala National Forest and Lake County, Florida, 1990-99 Figure 13. Distribution of dissolved oxygen, nitrate, Kjeldahl nitrogen, and phosphate in springs and in wells tapping the surficial aquifer system and the Upper Floridan aquifer. contribute to the concentrations of major ions and TDS present in the surficial aquifer system at that location of the aquifer. However, the number of samples col- (figs. 8 and 9) could be the result of water discharging lected for analysis of most water-quality constituents of from the Upper Floridan aquifer upward into the the surficial aquifer system in Lake County is 20 or surficial aquifer system. less; hence, determining the primary factors affecting The primary source of dissolved oxygen in water quality is difficult. ground water is precipitation that recharges the aquifer An important process affecting water quality in (Hem, 1989). Dissolved-oxygen concentrations in the surficial aquifer system in the Ocala NF is mixing ground water generally decrease over time as the with water from the Upper Floridan aquifer. For exam- oxygen in the water reacts with minerals and organic ple, water-level data from a pair of wells (405 and 406 material. Hence, the abundance of dissolved oxygen in in fig. 5) near the northern boundary of the Ocala NF the surficial aquifer system indicates rapid ground- indicated that water levels were consistently higher in water recharge and (or) the lack of reactive minerals in the Upper Floridan aquifer than in the surficial aquifer the aquifer. Rapid ground-water recharge can allow the system. Hence, calcium-magnesium-bicarbonate water aquifer to be susceptible to surface contamination.

Ground-Water Quality 19 Figure 14. Nitrate concentrations in samples from wells tapping the surficial aquifer system.

20 Ground-Water Quality of the Surficial Aquifer System and the Upper Floridan Aquifer, Ocala National Forest and Lake County, Florida, 1990-99 Differences in water quality of the surficial Upper Floridan Aquifer aquifer system in Ocala NF and Lake County possibly is related to land use. Locally, nitrate concentrations in Water throughout most of the Upper Floridan the surficial aquifer system are elevated. Nitrate con- aquifer is a calcium-bicarbonate or calcium-magne- centrations are greater than 1.0 mg/L in two samples sium-bicarbonate type (figs. 16 and 17). Concentra- from Lake County and one sample from the Ocala NF tions of TDS were less than 250 mg/L in 77 percent of (fig. 14). Nitrate concentrations greater than 1.0 mg/L the samples collected throughout the study area. Near in ground water generally are related to land-use prac- the St. Johns River and Lake George, TDS concentrations ranged from about 2,000 to nearly 12,000 mg/L tices, such as septic systems or land application of fer- (fig. 18). A total of 14 of 111 samples from wells had tilizers. Hence, the water quality of the surficial aquifer concentrations of TDS that exceeded the NSDWR of system in parts of the study area could be affected by 500 mg/L. A total of 14 of 135 samples had chloride present and (or) past land use. Because constituents concentrations that exceeded the NSDWR of 250 mg/L, such as nitrate can remain in ground water for many and 5 of 131 samples had sulfate concentrations that years, elevated concentrations of nitrate in ground exceeded the NSDWR of 250 mg/L. water do not necessarily indicate the effects of present In general, water-quality conditions and the land use, but could have resulted from previous land- concentrations of most major ions in the Upper Flori- use practices. dan aquifer do not differ significantly between samples Applications of fertilizer and pumping water collected in the Ocala NF and Lake County. In southern from the Upper Floridan aquifer to irrigate citrus Lake County, the dominant cation was calcium, groves in Lake County also could be increasing the pH whereas further north in Lake County and the Ocala and concentrations of major ions in the surficial aquifer NF, the dominant cations were calcium and magne- system. Nitrate concentrations in the surficial aquifer sium. Bicarbonate concentrations generally were system in Lake County were positively correlated to greater in samples from wells in Lake County than in pH (r = 0.75); however, sample size was only 13 samples from the Ocala NF. Near the St. Johns and (fig. 15). These results are in agreement with German Wekiva Rivers, sodium, chloride, and sulfate were the (1997) who determined that concentrations of major dominant ions (figs. 16 and 17). This change to a constituents and nitrate in the surficial aquifer system sodium-chloride-sulfate water type corresponds to the increases in concentrations of sulfate, chloride, and were greater in areas underlying citrus groves in Lake TDS observed in these areas (figs. 18, 19, and 20). and Orange Counties than in a forested area in the Concentrations of most major ions and TDS Ocala NF. generally are greater in the Upper Floridan aquifer than in the surficial aquifer system (tables 2 and 3; figs. 11 and 12). Throughout the Ocala NF and Lake County, median pH and concentrations of calcium, magnesium, and bicarbonate are significantly greater (p<0.01) in samples from the Upper Floridan aquifer than in samples from the surficial aquifer system. In addition, in the Ocala NF, median concentrations of sodium, potassium, sulfate, and chloride also are significantly greater (p<0.01) in samples from the Upper Floridan aquifer than in samples from the surficial aquifer system. In Lake County, potassium concentrations are greater (p = 0.04) in the samples from the surficial aquifer system than in samples from the Upper Floridan aquifer. Most of the water-quality differences between the surficial aquifer system and the Upper Floridan aquifer probably are related to differences in lithology and the Figure 15. Relation of nitrate concentrations to pH in wells greater solubility of carbonate rocks in comparison to tapping the surficial aquifer system in Lake County, Florida. quartz sand.

Ground-Water Quality 21 Figure 16. Relative concentrations of calcium, magnesium, and sodium in samples from wells tapping the Upper Floridan aquifer.

22 Ground-Water Quality of the Surficial Aquifer System and the Upper Floridan Aquifer, Ocala National Forest and Lake County, Florida, 1990-99 Figure 17. Relative concentrations of bicarbonate, sulfate, and chloride in samples from wells tapping the Upper Floridan aquifer.

Ground-Water Quality 23 Figure 18. Concentrations of total dissolved solids in samples from wells tapping the Upper Floridan aquifer.

24 Ground-Water Quality of the Surficial Aquifer System and the Upper Floridan Aquifer, Ocala National Forest and Lake County, Florida, 1990-99 Figure 19. Sulfate concentrations in samples from wells tapping the Upper Floridan aquifer.

Ground-Water Quality 25 Figure 20. Chloride concentrations in samples from wells tapping the Upper Floridan aquifer.

26 Ground-Water Quality of the Surficial Aquifer System and the Upper Floridan Aquifer, Ocala National Forest and Lake County, Florida, 1990-99 Table 3. Summary statistics of ground-water quality from Upper Floridan aquifer springs and wells [µS/cm, microsiemens per centimeter; °C, degrees celsius; mg/L, milligrams per liter; N, nitrogen; P, phosphorus; <, less than]

Lake County Ocala National Forest

Constituent Units Number Number of Minimum Median Maximum of Minimum Median Maximum samples samples Specific conductance µS/cm 81 132 289 3,160 57 101 360 18,200 pH standard 81 6.4 7.7 8.8 57 6.1 7.6 9.0 units Temperature °C 81 20.7 23.7 27.4 54 15.7 22.6 24.0 Dissolved oxygen mg/L 24 <0.1 <0.1 4.0 10 <0.1 1.8 7.3 Calcium mg/L 73 15 44 417 56 11 43 470 Magnesium mg/L 73 .9 7.6 58 56 1 12 320 Sodium mg/L 73 2.5 5.6 430 56 2.4 7.7 3,100 Potassium mg/L 73 .3 .8 13 56 .2 1.0 65 Bicarbonate mg/L 65 43 139 551 52 11 101 254 Sulfate mg/L 82 .1 6.6 380 74 .1 18 1,000 Chloride mg/L 86 3 10 695 74 4 18 6,000 Fluoride mg/L 72 <.1 .19 0.35 55 <.1 0.1 0.4 Dissolved solids, total mg/L 81 59 176 2,022 57 56 204 11,900 Nitrite plus nitrate mg/L as N 47 <.02 .04 7.5 26 <.02 .05 .2 Kjeldahl nitrogen mg/L as N 44 <.2 .15 .79 17 <.2 .2 .88 Phosphate mg/L as P 38 <.01 .05 .14 19 .01 .03 .13

Water-quality data were available from a total Concentrations of nutrients generally are low in of 27 springs. In 8 of 10 springs within the Ocala NF, the Upper Floridan aquifer in the Ocala NF (table 3). the water type is sodium-chloride or sodium-chloride- Nitrate concentrations in samples ranged from less sulfate (figs. 21 and 22). The water type of springs in than 0.02 to 0.20 mg/L with a median of 0.03 mg/L central Lake County is calcium bicarbonate. Median (fig.13). In contrast, nitrate concentrations in samples concentrations of magnesium, sodium, potassium, from the Upper Floridan aquifer in Lake County sulfate, chloride, and total dissolved solids in samples ranged from less than 0.02 to 7.5 mg/L with a median from springs were significantly greater (p<0.01) than of 0.02 mg/L (fig. 13, table 3). Kjeldahl nitrogen in the in samples from wells tapping the Upper Floridan Upper Floridan aquifer ranged from less than 0.2 to aquifer (figs. 11 and 12). These results are probably 0.88 mg/L in the Ocala NF, and from less than 0.2 to related to the geographical distribution of springs and 0.79 mg/L in Lake County. Phosphate ranged from do not indicate significant hydrogeologic differences 0.01 to 0.13 mg/L with a median of 0.03 mg/L in sam- between springs and wells. Most springs are located in ples from the Ocala NF. In samples from Lake County, the discharge areas of the Upper Floridan aquifer near phosphate concentrations were not significantly dif- the St. Johns and Wekiva Rivers. As previously noted, ferent, ranging from less than 0.01 to 0.14 mg/L with the aquifer in this area has relatively high concentra- a median of 0.05 mg/L. tions of sodium, chloride, and total dissolved solids. Median concentration of Kjeldahl nitrogen was A comparison of samples from springs and nearby significantly greater (p<0.01) in samples from wells in wells tapping the Upper Floridan aquifer indicates that the Ocala NF than in samples from springs (fig. 13). both have similar geochemistry (figs. 16, 17, 21, and 22). Concentrations of nutrients were not significantly Dissolved-oxygen concentrations measured in different between samples from the surficial aquifer samples from wells tapping the Upper Floridan aquifer system and the Upper Floridan aquifer in either the ranged from less than 0.1 to 7.3 mg/L. Although the Ocala NF or Lake County, possibly because of the data are not evenly distributed geographically (fig. 23), paucity of data for the surficial aquifer system. the samples indicate that dissolved oxygen is present in Similar to the surficial aquifer system, water- parts of the Upper Floridan aquifer in the Ocala NF and quality conditions of the Upper Floridan aquifer Lake County. The presence of dissolved oxygen indi- probably are related to the lithology of the aquifer, cates relatively rapid recharge in some parts of the the mixing of fresh recharge water with saline water Upper Floridan aquifer. from deeper in the aquifer, and the effects of land use.

Ground-Water Quality 27 Figure 21. Relative concentrations of calcium, magnesium, and sodium in samples from springs discharging from the Upper Floridan aquifer.

28 Ground-Water Quality of the Surficial Aquifer System and the Upper Floridan Aquifer, Ocala National Forest and Lake County, Florida, 1990-99 Figure 22. Relative concentrations of bicarbonate, sulfate, and chloride in samples from springs discharging from the Upper Floridan aquifer.

Ground-Water Quality 29 Figure 23. Concentrations of dissolved oxygen in samples from wells tapping the Upper Floridan aquifer.

30 Ground-Water Quality of the Surficial Aquifer System and the Upper Floridan Aquifer, Ocala National Forest and Lake County, Florida, 1990-99 The calcium-magnesium-bicarbonate water type of SUMMARY most samples indicates dissolution of the carbonate rocks that form the aquifer. The change in cation This report describes water-quality conditions in the surficial aquifer system and the Upper Floridan distribution from calcium to calcium-magnesium aquifer underlying the Ocala National Forest and Lake probably is related to an increase of dolomite in the County, Florida, from 1990-99. Data from two compre- carbonate sequence of the aquifer. The difference in hensive water-resources studies, one of the Ocala bicarbonate concentrations between samples from the National Forest and the other of Lake County, are Ocala NF and Lake County also are related to the presented. The study area, which contains numerous amount of dolomite in the sequence. Because dolo- lakes, is drained by the St. Johns River and its tributar- mite is less soluble than limestone (Drever, 1988), a ies. Numerous karst features are present in parts of the relatively larger amount of dolomite in the sequence study area including sinkholes, springs, and caves. would result in a lower concentration of bicarbonate. The surficial aquifer system, which is uncon- Nonetheless, the overall quality of water is similar fined, is recharged by precipitation and discharges to between the Ocala NF and Lake County, and is indic- nearby lakes and streams. The Upper Floridan aquifer ative of the relatively homogeneous lithology of the is recharged by the surficial aquifer system either by Upper Floridan aquifer. slow leakage through the intermediate confining unit, or more rapidly in places where the intermediate con- The sodium-chloride water and high concentra- fining unit is missing or breached. Discharge from the tions of TDS near the St. Johns River probably result Upper Floridan aquifer occurs in places where the from upward migration of saline water, probably relict potentiometric surface is higher than the water table, at sea water from high stands of sea level. The sodium- springs, flowing wells, and by diffuse leakage to the chloride water and high concentrations of TDS in the overlying surficial aquifer system. Upper Floridan aquifer are spatially isolated near the As of 1994, land use in the Ocala National Forest St. Johns River. Ground water east of the St. Johns consisted primarily of second-growth forests (65 percent), River in Putnam and Volusia Counties is calcium bicar- and water and wetlands (19 percent). In contrast, land use bonate with TDS concentrations less than 200 mg/L in Lake County was more diverse. In 1994, land use in (Tibbals, 1990). Hence, lateral migration of saline Lake County was a mixture of agriculture (30 percent), water from the Atlantic Ocean is unlikely. forest (18 percent), rangeland (7 percent), urban (6 percent), and water and wetlands (36 percent). Population in As in the surficial aquifer system, the presence of Lake County has been increasing in recent years, and dissolved oxygen in the Upper Floridan aquifer indi- present (2000) urban land use probably is greater than cates rapid recharge and (or) lack of reactive mineral 6 percent. constituents. In water from springs, the presence of dis- Ground-water samples were collected by the solved oxygen indicates that shallow, rapidly recharg- U.S. Geological Survey from 23 wells tapping the ing ground water is mixing with relict water from surficial aquifer system, and from 25 springs and deeper in the aquifer, confirming the conclusions of 88 wells tapping the Upper Floridan aquifer. These Toth (1999). Hence, the presence of dissolved oxygen data were supplemented with samples collected by the in parts of the Upper Floridan aquifer indicates that the St. Johns River Water Management District and Lake aquifer is susceptible to surface contamination. County Water Resources Management from 26 wells Water quality of the Upper Floridan aquifer tapping the surficial aquifer system, and from 2 springs appears to be affected by land use. For example, the and 53 wells tapping the Upper Floridan aquifer. Most samples were analyzed in the field for temperature, pH, maximum nitrate concentration in samples from wells and specific conductance, and in the laboratory for in the Ocala NF is only 0.20 mg/L. Low concentra- major ions (calcium, magnesium, sodium, potassium, tions of nutrients in the Upper Floridan aquifer in the sulfate, and chloride), alkalinity, and total dissolved Ocala NF probably are a result of the pristine, forested solids. A total of 98 samples were analyzed for nitrite land use of the area. In contrast, nitrate concentrations plus nitrate, 81 samples were analyzed for Kjeldahl were greater than 1.0 mg/L in 9 of 39 (23 percent) nitrogen, and 71 samples for phosphate. samples from wells in Lake County outside the Ocala The data were statistically analyzed using NF (fig. 24). Hence, nitrate concentrations of the non-parametric procedures to identify differences in Upper Floridan aquifer appear to be related to land use water quality between the aquifers, between site types in Lake County. (springs and wells), and between geographic locations.

Summary 31 Figure 24. Nitrate concentrations in samples from springs and from wells tapping the Upper Floridan aquifer.

32 Ground-Water Quality of the Surficial Aquifer System and the Upper Floridan Aquifer, Ocala National Forest and Lake County, Florida, 1990-99 Medians of groups of data were assumed significantly Dissolved oxygen is present in parts of the different from one another if the probability (p-value) Upper Floridan aquifer. Concentrations ranged from was less than 5 percent that the difference occurs by less than 0.1 to 7.3 milligrams per liter. Dissolved chance. oxygen present in the Upper Floridan aquifer indi- Water type throughout most of the Upper cates rapid ground-water recharge and (or) a lack of Floridan aquifer is calcium-bicarbonate or calcium- reactive mineral constituents. In springs, the presence magnesium-bicarbonate. Near the St. Johns and of dissolved oxygen indicates a mixing of shallow, Wekiva Rivers, however, sodium, chloride, and sulfate rapidly recharging ground water with the deep, con- are the dominant ions. Total dissolved solids concentra- nate sea water. The presence of dissolved oxygen in tions were low (less than 250 milligrams) throughout samples from springs and wells in the Upper Floridan most of the aquifer, but increased to nearly 12,000 mil- aquifer indicates that the aquifer is susceptible to ligrams per liter near the St. Johns and Wekiva Rivers. surface contamination. Concentrations of most major ions and total dissolved Water-quality conditions probably can be solids are significantly greater in the Upper Floridan attributed to a number of factors. Most water-quality aquifer than in the surficial aquifer system. A total of differences between the surficial aquifer system and 14 of 111 samples had concentrations that exceeded the the Upper Floridan aquifer probably are related to dif- National Secondary Drinking Water Regulations for ferences in lithology. Calcium-magnesium-bicarbon- total dissolved solids, 14 of 135 samples had concen- ate water type throughout most of the Upper Floridan trations that exceeded the National Secondary Drinking aquifer results from the dissolution of the carbonate Water Regulations for chloride, and 5 of 131 samples rocks, which form the aquifer. The high concentra- had concentrations that exceeded the National Second- tions of sodium and chloride in the Upper Floridan ary Drinking Water Regulations for sulfate. aquifer near the St. Johns River probably result from The water type within the surficial aquifer system the upward migration of saline water. Relatively high is laterally diverse, and can be calcium-bicarbonate, concentrations of sodium, chloride, and sulfate in sodium-chloride, or mixed cations and mixed anions. samples from many of the springs probably are related Concentrations of major ions and total dissolved solids to the geographical proximity of most springs to the are generally low; total dissolved solids concentrations St. Johns and Wekiva Rivers. Comparison of samples ranged from 3 to 356 milligrams per liter with a median from springs and nearby wells tapping the Upper of 41 milligrams per liter. None of the samples had con- Floridan aquifer indicate similar geochemistry of both centrations of total dissolved solids, chloride, or sulfate site types. that exceeded any National Secondary Drinking Water Regulations. In general, pH and concentrations of cal- Water quality of the Upper Floridan aquifer also cium, magnesium, potassium, bicarbonate, sulfate, and appears to be affected by land use. Nitrate concentra- total dissolved solids in the surficial aquifer system are tions were elevated (greater than 1 milligram per liter) significantly greater in samples from Lake County than in 9 of 39 samples (23 percent) collected from wells in samples from the Ocala National Forest. in Lake County. In contrast, nitrate concentrations in Dissolved-oxygen concentrations in the surficial samples from the Upper Floridan aquifer in the Ocala aquifer system in the Ocala National Forest ranged from National Forest did not exceed 0.20 milligram per less than 0.1 to 8.2 milligrams per liter. No data were liter. available for the surficial aquifer system in Lake County. In summary, the Ocala National Forest and Lake Concentrations of nutrients in the surficial aquifer County contain abundant ground-water resources. system in the Ocala National Forest generally were These ground-water resources are important for low—below 1.0 milligrams per liter in most samples. agriculture, domestic and public supply, recreation, Nitrate and Kjeldahl nitrogen were detected more fre- and for the aquatic ecology of the study area. The quently in the surficial aquifer system in Lake County surficial aquifer system and Upper Floridan aquifer, than in the Ocala NF. however, are susceptible to surface contamination. Nitrogen concentrations are elevated in parts of Present and (or) past land uses in parts of Lake County the Upper Floridan aquifer outside the Ocala National could have affected the ground-water quality as indi- Forest. Nitrate concentrations in samples ranged from cated by elevated concentrations of nitrate. Further less than 0.02 to 7.5 milligrams per liter, Kjeldahl studies to better quantify the effects of land use nitrogen in samples ranged from less than 0.20 to on ground-water quality, particularly with respect 0.88 milligram per liter, and phosphate ranged from to the rapid urbanization of parts of the study area, less than 0.01 to 0.14 milligram per liter. would be beneficial.

Summary 33 REFERENCES U.S. Geological Survey Water-Resources Investiga- tions Report 96-4181, 100 p. Adamski, J.C., 1998, Potentiometric surface of the Upper National Atmospheric Deposition Program, 2000, Annual Floridan aquifer in the St. Johns River Water Manage- and seasonal data summary for site FL03 [cited October ment District and vicinity, Florida, May 1998: U.S. 2, 2000] http://nadp.sws.uiuc.edu/ads/FL03.pdf. Geological Survey Open-File Report 98-648, 1 sheet. National Oceanic and Atmospheric Administration, 1992, Cooke, C.W., 1945, Geology of Florida: Florida Geological Monthly station normals of temperature, precipitation, Survey Bulletin 29, 339 p. Drever, J.I., 1988, The geochemistry of natural waters (2d and heating and cooling degree days 1961-1990: in ed.): Englewood Cliffs, New Jersey, Prentice Hall, Climatography of the United States No. 81 (by State) 437 p. for Florida, Asheville, N.C., 26 p. Faulkner, G.L., 1973, Geohydrology of the Cross-Florida Phelps, G.G., 1994, Hydrogeology, water quality, and poten- Barge Canal area with special reference to the Ocala tial for contamination of the Upper Floridan aquifer in vicinity: U.S. Geological Survey Water-Resources the Silver Springs basin, central Marion County, Investigations Report 1-73, 117 p. Florida: U.S. Geological Survey Water-Resources Fenneman, N.M., 1938, Physiography of eastern United Investigations Report 92-4159, 69 p. States: New York, McGraw-Hill Book Co., Inc., 714 p. Rosenau, J.C., Faulkner, G.L., Hendry, C.W., Jr., and Hull, German, E.R., 1997, Analysis of nonpoint-source ground- R.W., 1977, Springs of Florida (2d ed.): Florida Bureau water contamination in relation to land use: Assess- of Geology Bulletin 31, 461 p. ment of nonpoint-source contamination in central Rutledge, A.T., 1987, Effects of land use on ground-water Florida: U.S. Geological Survey Water-Supply Paper 2381-F, 60 p. quality in central Florida--Preliminary results: U.S. Helsel, D.R., and Hirsch, R.M., 1992, Statistical methods in Geological Survey Toxic Waste--Ground-Water Con- water resources: Amsterdam, Elsevier Science Pub- tamination Program: U.S. Geological Survey Water- lishers, 522 p. Resources Investigations Report 86-4163, 49 p. Hem, J.D., 1989, Study and interpretation of the chemical Sepulveda, Nicasio, 1997, Potentiometric surface of the characteristics of natural water (3d ed.): U.S. Geologi- Upper Floridan aquifer in the St. Johns River Water cal Survey Water-Supply Paper 2254, 263 p. Management District and vicinity, Florida, May 1997: Katz, B.G., 1992, Hydrochemistry of the Upper Floridan U.S. Geological Survey Open-File Report 97-572, aquifer, Florida: U.S. Geological Survey Water- 1 sheet. Resources Investigations Report 91-4196, 37 p. Sprinkle, C.L., 1989, Geochemistry of the Floridan aquifer Knochenmus, D.D., and Hughes, G.H., 1976, Hydrology of system in Florida and in parts of Georgia, South Caro- Lake County, Florida: U.S. Geological Survey Water- lina, and Alabama: U.S. Geological Survey Profes- Resources Investigation 76-72, 100 p. sional Paper 1403-I, 105 p. Knowles, Leel, Jr., 1996, Estimation of evapotranspiration in Stringfield, V.T., 1933, Ground water investigations in the Rainbow Springs and Silver Springs basins in north- central Florida: U.S. Geological Survey Water- Florida: Florida Geological Survey Bulletin 11, 33 p. Resources Investigations Report 96-4024, 37 p. ———1936, Artesian water in the Florida peninsula: U.S. Matson, G.C., and Sanford, Samuel, 1913, Geology and Geological Survey Water-Supply Paper 773-C. ground waters of Florida: U.S. Geological Survey Tibbals, C.H., 1990, Hydrology of the Floridan Aquifer Water-Supply Paper 319, 445 p. System in east-central Florida: U.S. Geological Survey Merrit, M.L., 1998, Potentiometric surface of the Upper Professional Paper 1403-E, 98 p. Floridan aquifer in the St. Johns River Water Manage- Toth, D.J., 1999, Water quality and isotope concentrations ment District and vicinity, Florida, September 1997: from selected springs in the St. Johns River Water U.S. Geological Survey Open-File Report 98-183, Management District: St. Johns River Water Manage- 1 sheet. ment District Technical Publication SJ99-2, 67 p. Miller, J.A., 1986, Hydrogeologic framework of the Floridan aquifer system in Florida and in parts of Georgia, U.S. Environmental Protection Agency, 2000, Current Alabama, and South Carolina: U.S. Geological Survey drinking water standards [cited 22 September 2000] Professional Paper 1403-B, 91 p. http//:www.epa.gov/OGWDW/mcl.html. Murray, L.C., Jr., and Halford, K.J., 1996, Hydrogeologic White, W.A., 1970, The geomorphology of the Florida conditions and simulation of ground-water flow in the peninsula: Florida Department of Natural Resources, greater Orlando metropolitan area, east-central Florida: Bureau of Geology Geological Bulletin, No. 51, 164 p.

34 Ground-Water Quality of the Surficial Aquifer System and the Upper Floridan Aquifer, Ocala National Forest and Lake County, Florida, 1990-99 APPENDIX

Appendix 35 1.7 <.1 <.1 <.1 <.1 <.1 ------Dis- (mg/L) solved oxygen ------84 47 118 200 290 594 207 244 322 508 545 253 230 619 359 365 103 289 316 243 218 230 190 346 422 S/cm) tance µ ( Specific conduc- ) C ------o 24.0 23.5 23.9 22.5 22.0 23.9 25.4 24.0 22.5 22.3 23.2 22.0 24.9 24.2 23.8 22.5 23.7 23.8 22.9 24.3 24.6 25.8 24.5 23.5 23.3 25.5 ture ( Water tempera- dan aquifer i F F S F F F F S F F S F F F F F F F S F F F S F F F S S F S Aquifer 5 ------85 25 18 64 81 70 96 85 24 66 16 30 20 118 110 262 160 100 123 605 143 (feet) length length Casing ------35 15 85 44 30 35 25 115 437 192 190 101 485 404 390 543 213 329 155 160 918 146 291 Well land land (feet depth below below surface) mbers shown in figures 5 and 6] u of of Date sample 04/15/93 08/02/93 08/02/93 02/05/97 02/02/97 12/12/96 08/12/98 08/13/98 08/14/98 02/12/97 05/07/98 08/03/93 12/12/96 07/26/92 05/30/97 07/07/92 09/08/99 09/27/99 04/14/97 09/22/99 03/28/94 02/12/97 05/06/93 01/23/97 05/04/93 08/18/98 05/05/93 12/05/90 02/14/97 11/09/90 County Lake Lake Lake Lake Lake Lake Lake Lake Lake Lake Lake Lake Lake Lake Lake Lake Lake Lake Lake Lake Lake Lake Lake Lake Lake Lake Lake Lake Lake Lake agency Collecting SJRWMD SJRWMD SJRWMD USGS USGS USGS SJRWMD SJRWMD SJRWMD USGS USGS SJRWMD USGS SJRWMD USGS SJRWMD USGS USGS SJRWMD USGS SJRWMD USGS SJRWMD USGS SJRWMD SJRWMD SJRWMD SJRWMD USGS SJRWMD C; <, lessC; than; unknown --, not or analyzed. Collectingagency: LC,St.Johns Lake River County; SJRWMD, o Site name S/cm, microsiemens per centimeter at 25 25 at centimeter per microsiemens S/cm, µ L-0623 SandMine deep L-0051 near Horsehead Pond L-0050 deep 6” Eva L-0555 Green Swamp 4” deep (HayesGrubb-LK751W/LK7425) Lake Keene near deep 4” Burger) (S. Replacement Bros. Lykes L-0709 L-0710 L-0677 ROMPdeep 101 L-0056 near Bay Lake near Bay Lake SWFWMD site USGS2” shallow, Lake LouisaState Parkdeep 4” L-0053 D. Pattondeep 6” near EvaFiretower L-0476 LCFD District 9 Station 1 4” deep near Crescent Lake, Clermont L-0459 Clermont deep, 4” Tyner) (S. Nursery Garden Country Bernard DuFrene2” deepnear Groveland Johns Lake 4” deep L-0052 near ClermontJohns Lake Well L-0646 Mascotte 6” deep L-0062 near Mascotte L-0041 Mascotte near 6” shallow Mascotte Edgewater Beach 4” deep nearEastLake Johns L-0596 Junction4” deep L-0199 SiteWaits 38 Turnpike, Junction4” shallow L-0044 Waits Site 38 Turnpike, L-0320 deep 8” of Mascotte City L-0325 C, degreeCelsius; o 3 4 5 6 7 9 11 10 12 13 14 16 19 20 22 23 24 25 26 27 28 29 30 31 34 35 36 37 38 39 ber Map num- WELLS Site identification, well construction information, and water-quality data from the surficial aquifer system and the Upper Flor Upper the and system aquifer surficial the from data water-quality and information, construction well identification, Site Site Site number identification 282225081413101 282241081443901 282241081443902 282245081492601 282318081544003 282502081422301 282528081424801 282528081424802 282533081430801 282717081553101 282717081554401 282729081443301 282823081500401 283003081411401 283019081455701 283024081410901 283028081454701 283114081503401 283114081503901 283128081404701 283149081422801 283204081544901 283204081544902 283232081394101 283349081445001 283355081411701 283355081411702 283403081400002 283432081530601 283443081404002 Appendix. Appendix. liter; per milligrams [mg/L, Upper FloridanManagement aquifer; S,Aquifer: District; surficialU.S. USGS, aquifer GeologicalWater F, system. Survey. n Map

36 Ground-Water Quality of the Surficial Aquifer System and the Upper Floridan Aquifer, Ocala National Forest and Lake County, Florida Dis- lated lated calcu- (mg/L) solved solids, Dis- total total (mg/L) solved solids, Silica Silica (mg/L)

) 4 idan aquifer--Continued idan (mg/L as SO as Sulfate (mg/L) Chloride Chloride sium sium Potas- (mg/L) umbersshownfigures in 5 and 6] (mg/L) Sodium Sodium sium (mg/L) Magne- (mg/L) Calcium Calcium P) C;than; <, less--, unknown or not analyzed. Collecting agency: LC, LakeCounty; St.River Johns SJRWMD, phate phate Phos- o (mg/L as plus plus as N) (mg/L (mg/L Nitrite nitrate nitrate plus organic nitrogen nitrogen Ammonia (mg/L as N) (mg/L as ) 3 as (mg/L Bicar- bonate CaCO S/cm, microsiemens per centimeter at 25 25 at centimeter per microsiemens S/cm, ) µ 3 CaCO (mg/L as Alkalinity Alkalinity pH dard dard (stan- units) C, degree Celsius; o ber Map num- WELLS Site identification, well construction information, and water-quality data from the surficial aquifer system and the Upper Flor Upper the and system aquifer surficial the from data water-quality and information, construction well identification, Site Site number identification 282225081413101282241081443901282241081443902 3282245081492601 4 --282318081544003 5 6 8.0282502081422301 5.0 7282528081424801 7.6 --282528081424802 6.9 9 -- 10282533081430801 -- 143 11282717081553101 7.9 297 12 7.4 -- -- 13 5.6 174282717081554401 -- 100 7.3 362282729081443301 452 14 6.7282823081500401 -- 18 16283003081411401 122 .20 113 <.20 551 19 6.3283019081455701 262 .23 -- 20 8.2 22 137 22 7.9 --283024081410901 <.02 .02 -- 320 .47 -- --283028081454701 .02 23 7.2 --283114081503401 -- 106 24 ------283114081503901 .08 -- -- <.02 25 ------283128081404701 107 -- 129 -- 26 7.2 -- -- 6.9 27 56283149081422801 -- -- 34 131 -- .11283204081544901 ------28 7.1 -- 4.5283204081544902 <.20 -- 29 110 .20 --283232081394101 2.1 35 -- 30 -- --283349081445001 -- 35 .89 -- -- 1.3 31 6.7 ------.04 416 3.8 34 5.5 --283355081411701 4 4.1 2.7 6.4 3.2 43283355081411702 151 -- 4.8 -- 8.0 35 48 ------4.1283403081400002 19 .07 100 -- -- 36 .22 1.5 --283432081530601 .02 11 <.20 3 184 81 2.3 37 8.1283443081404002 -- -- 1.8 2.2 38 6.5 42 -- 7.3 ------3.2 6.1 39 23 6.4 8.0 .63 6.8 -- -- 99 -- .05 59 7.0 7.4 .7 11 .6 8.7 .79 6.4 ------5.5 1.0 13 12 6.4 <.02 2.3 61 -- -- .1 .10 150 5.5 72 -- .03 18 14 .30 -- .49 4.6 .06 1.6 -- -- .81 3.6 -- -- 183 18 .01 3.0 9.1 14 .33 .80 -- -- 4.5 13 -- <.20 ------.14 -- 15 .1 12 .4 .40 2 -- 10 2.9 .80 -- -- 28 .47 -- <.20 12 178 -- .02 -- .40 103 -- -- 5.8 -- 12 33 10 -- -- 6.3 .14 59 6.6 28 161 ------17. 103 -- 2.5 .10 1.4 11 3.9 ------.02 -- 18 348 -- 120 3.4 3.1 ------28 -- 1.2 14 -- 2.3 131 <.01 -- 64 -- 24 6.0 -- 358 26 107 -- -- 5.9 -- 11 -- .64 -- 131 -- 5.4 182 50 303 3.0 62 12 87 21 9.8 -- -- .50 7.7 10 1.9 -- -- 182 303 148 -- 50 13 4.0 27 .30 -- 2.9 14 137 10 3.9 6.4 122 -- 5.3 57 -- .25 -- .8 8.3 137 14.8 ------5.7 3.0 3.2 -- 388 .48 17.5 -- 2.9 .63 23 .30 6.0 11 -- -- 327 375 -- .6 -- -- 6.3 6.4 11 13 2.6 10 1.6 -- 27 9.7 206 11 2.5 -- 210 4.3 7.5 40 -- 2.9 5.6 17 178 206 -- 161 210 39 -- 6.1 11.0 40 -- -- 178 -- 161 4 -- 140 115 10 7.1 -- -- 131 122 4 115 -- 202 122 ------198 96 -- 247 96 247 Water Management District; USGS, U.S. Geological Survey. Aquifer: F, Upper Management Floridanaquifer;District;surficial S, Aquifer: USGS,aquiferF, U.S.GeologicalWater system.MapSurvey. n Appendix. Appendix. liter; per milligrams [mg/L,

Appendix 37 Dis- (mg/L) solved oxygen S/cm) tance µ ( Specific conduc- ) C o ture ( Water tempera- idan aquifer--Continued idan Aquifer (feet) length length Casing Well land land (feet depth below below surface) umbers shown in figures 5 and 6] of of Date sample County agency Collecting C; <, lessC; than; unknown --, not or analyzed. Collectingagency: LC,St.Johns Lake River County; SJRWMD, o freeflow USGS Lake 02/05/97 141 -- F 24.0 198 -- ” deepnear LakeLucy USGS Lake 12/12/96 141 73 F 21.5 350 -- ” deep, 4 mi N of CenterHill USGS Lake 01/14/97 -- -- F 23.5 331 -- deep #3L-0591 SJRWMD Lake 05/04/93 350 162 F 23.9 366 <.1 ” ” shallowL-0287 SJRWMD Lake 06/15/93 43 38 S 23.3 457 -- ” deep USGS Lake 03/05/97 -- -- F 25.3 255 -- deep Office L-0139at SJRWMD USGS Lake 01/23/97 650 575 F 24.2 224 -- deep, N of Mascotte USGS Lake 12/12/96 -- -- F 23.0 253 1.1 Site name deep USGS Lake 01/29/97 90 -- F 24.3 436 3.5 ” ” ” ” deep USGS Lake 01/09/97 -- -- F 23.2 338 <.1 ” shallow (8A) LC Lake 02/26/99 -- -- F 23.1 195 .4 freeflow USGS Lake 08/24/99 120 -- F 24.3 170 <.1 intermittentflow USGS Lake 11/22/96 180 -- F 24.0 134 -- ” shallow L-0096,33of SROkahumpka S SJRWMD Lake 06/03/91 111 111 S 24.2 309 -- ” ” ” S/cm, microsiemens per centimeter at 25 25 at centimeter per microsiemens S/cm, µ deep USGS Lake 02/05/97 539 145 F 24.4 242 -- ” deep USGS Lake 11/19/98 -- -- F 23.7 226 -- deep,Ferndale USGS Lake 01/29/97 123 -- F 23.7 179 2.2 ” ” Dr. Phillips Dr. & Sons(Minute Maid Co.)4 C, degreeCelsius; o ber Map num- Site identification, well construction information, and water-quality data from the surficial aquifer system and the Upper Flor Upper the and system aquifer surficial the from data water-quality and information, construction well identification, Site Site Site number identification 284134081564201 65284157081405401 Sunshine Peat (prev Hi Acres) 4 284209081424401 67284209081424402 68 L-0283284253081441101 69 L-0285 75 L-0286 Astatula,Park, Swaffer J. 4 SJRWMD SJRWMD Lake SJRWMD Lake Lake 06/10/93 06/27/90 06/15/93 38 14 33 33 4 28 S S S 23.2 24.5 24.1 240 156 344 ------284320081410701 77 Apopka-Beauclair Canal 4 284443081483201284504081441501 84 85 L-0713 Astatula 1 Landfill4 SJRWMD Lake 04/15/98 -- -- F ------284330081464201 81 of Howey In TheHills 14 Town 284328081515901 79 Creek Farms8 283621081405001283652081412901 45283655081412701 46 L-0674 47 L-0675 Freeflow 4 283744081415002283828081535701 50 53 L-0308 Sunset LakesSki Center 4 SJRWMD SJRWMD Lake Lake 04/16/96 04/16/96 SJRWMD -- Lake -- 12/05/90 -- -- 15 F F 10 -- -- S -- -- 22.0 -- -- 70 -- 283549081401701 44 Montverde School 6 283702081413801283720081421801 48 49 L-0676 Ferndale Baptist Church4 283905081485401283937081422101 54284005081413901 56 Novelty Crystal4 Plant 57 Lake Apopka Restoration 4 Area (SJRWMD) 284024081405301 L-0291284024081405302 59284122081534401 60 L-0300284122081534402 63 L-0301 64 4 deep Groveland L-0095nearTower Okahumpka Groveland 4 Tower SJRWMD Lake SJRWMD 05/05/93 Lake 364 09/09/96 148 185 SJRWMD Lake F SJRWMD 53 SJRWMD Lake 03/21/90 Lake 23.9 F 05/16/90 100 12/05/90 390 416 -- <.1 -- 22 92 F -- 20 F -- S -- -- 20.0 -- 590 ------283538081545401283540081402401 42 43 L-0693 Montverde School 3 SJRWMD Lake 04/14/97284322081410301 78 25 Apopka Lock, Field Station, 4 10 S 23.5 841 -- 283535081545201 41 G. Barton 4 283530081514501 40 Water Management District; USGS, U.S. Geological Survey. Aquifer: F, Upper FloridanManagement aquifer; S,Aquifer: District; surficialU.S. USGS, aquifer GeologicalWater F, system. Survey. n Map Appendix. Appendix. liter; per milligrams [mg/L,

38 Ground-Water Quality of the Surficial Aquifer System and the Upper Floridan Aquifer, Ocala National Forest and Lake County, Florida Dis- lated lated calcu- (mg/L) solved solids, Dis- total total (mg/L) solved solids, Silica Silica (mg/L)

) 4 idan aquifer--Continued idan (mg/L as SO as Sulfate (mg/L) Chloride Chloride sium sium Potas- (mg/L) umbersshownfigures in 5 and 6] (mg/L) Sodium Sodium sium (mg/L) Magne- (mg/L) Calcium Calcium P) C;than; <, less--, unknown or not analyzed. Collecting agency: LC, LakeCounty; St.River Johns SJRWMD, phate phate Phos- o (mg/L as plus plus as N) (mg/L (mg/L Nitrite nitrate nitrate plus organic nitrogen nitrogen Ammonia (mg/L as N) (mg/L as ) 3 as (mg/L Bicar- bonate CaCO S/cm, microsiemens per centimeter at 25 25 at centimeter per microsiemens S/cm, ) µ 3 CaCO (mg/L as Alkalinity Alkalinity pH dard dard (stan- units) C, degree Celsius; o ber Map num- Site identification, well construction information, and water-quality data from the surficial aquifer system and the Upper Flor Upper the and system aquifer surficial the from data water-quality and information, construction well identification, Site Site number identification 283530081514501283535081545201 40283538081545401 41283540081402401 42 7.7283549081401701 43 6.7 -- 44283621081405001 153 8.0283652081412901 35 45 7.8283655081412701 187 46283702081413801 14 -- 49 47283720081421801 43 -- 48 -- 49 8.3 17 --283744081415002 60 --283828081535701 -- 50 7.9 -- --283905081485401 -- 59 53283937081422101 ------54 --284005081413901 -- -- 78 56 7.6 72 -- -- 57 7.4 .22284024081405301 8.1 --284024081405302 -- 95 ------94 59 --284122081534401 147 60 -- <.20 --284122081534402 .52 -- 68 63284134081564201 115 ------179 64 58 -- <.20 ------4.3 65 7.3284157081405401 .01 83 -- 20 7.9284209081424401 -- <.20 7.5 67 8.6 --284209081424402 3.3 -- -- 4 -- .22 15 68 ------284253081441101 .02 100 69 7.2 4.7 <.20 --284320081410701 143 3.3 -- -- 75 7.9 .02 <.02 -- -- 122 21 77 2.8 7.6 -- 4.4 -- --284322081410301 -- 11 174 4.3 7.7 -- --284328081515901 .08 44 78 7.9 -- --284330081464201 .06 .7 -- 79 3.0 -- 2.9 5.8 ------284443081483201 122 -- -- 81 6.9 .49 -- 5.4 ------284504081441501 .02 104 41 20 84 7.6 15 52 ------2.6 149 85 7.5 4.4 -- .7 29 -- -- 127 24 4.2 ------3.0 .02 106 -- 1.7 -- 8.8 11 .84 6.2 4.9 -- 7.0 ------<.20 9.3 .4 21 1.0 129 1.4 7.3 -- -- <.20 .05 .14 ------5.0 22 ------11 .04 -- 7.0 .6 2.2 -- <.02 11 -- 2.0 68 <.02 54 -- 4.7 .04 .10 6.6 -- -- .21 -- 91 -- .4 .21 -- -- 28 212 -- 8.0 .8 60 .03 4.5 7 7.0 6.3 -- .01 136 .36 2.4 -- .06 2.4 .4 12 200 21 .88 -- 51 2.0 .04 22 31 -- -- 6.0 34 -- 3.9 120 2.0 60 -- -- 31 16 14 9.9 5.7 6.0 .95 58 -- -- 4 11 .06 8.0 -- 9.8 6.7 -- 16 60 8.6 -- 83 6.5 <.02 ------106 7.6 1.7 1.9 1.0 7 40 5.6 -- 10 7.1 -- 47 11 5.0 83 -- 116 5.0 258 -- -- 89 .5 10 13 5.0 8.2 -- 52 -- 5.1 10 2.3 256 -- 1.0 168 21 4.0 5.4 198 12 .8 ------1.6 4.7 8.0 -- .9 -- 1.4 8.8 137 4.5 192 112 19 48 4.0 -- 7.1 11 7.9 -- -- 11 -- 8.8 7.1 102 -- 9 6.2 6.7 19 .6 1.1 ------.4 13 6.4 2 226 -- -- 174 .20 -- .8 14 8.4 8.5 12 226 356 -- 192 174 -- 23 -- 13 12 -- 3.5 -- 129 11 356 188 -- 154 196 74 129 118 6.3 9.9 10 6.8 139 28 196 118 74 140 15 -- 3.7 270 130 211 270 -- -- 211 100 -- 100 -- Water Management District; USGS, U.S. Geological Survey. Aquifer: F, Upper Management Floridanaquifer;District;surficial S, Aquifer: USGS,aquiferF, U.S.GeologicalWater system.MapSurvey. n Appendix. Appendix. liter; per milligrams [mg/L,

Appendix 39 Dis- (mg/L) solved oxygen S/cm) tance µ ( Specific conduc- ) C o ture ( Water tempera- idan aquifer--Continued idan Aquifer (feet) length length Casing Well land land (feet depth below below surface) umbers shown in figures 5 and 6] of of Date sample County agency Collecting C; <, lessC; than; unknown --, not or analyzed. Collectingagency: LC,St.Johns Lake River County; SJRWMD, o deep near Leesburg USGS Lake 01/24/97 -- -- F 23.2 245 -- ” int. flow #1, North USGS Lake 01/08/97 65 -- F 22.7 947 .1 freeflow #2, South USGS Lake 01/08/97 109 102 F 22.7 1,260 <.1 ” ” deep, Clearview Lake USGS Lake 02/20/97 350 203 F 23.9 283 -- ” deep nearOkahumpka USGS Lake 12/12/96 80 -- F 24.0 234 -- ” deepL-0593, 44A CR SJRWMD Lake 11/03/93 750 274 F 23.9 251 -- ” Site name deep #1 L-0037 SJRWMD Lake 01/10/95 363 102 F 22.4 2,240 -- shallow L-0289 SJRWMD Lake 11/02/93 50 40 S 23.8 56 -- ” ” deepL-0600 nearSorrento USGS Lake 08/31/99 205 160 F 23.6 213 <.1 ” deep #3 USGS Lake 03/05/97 752 155 F 23.3 274 -- deepL-0375 USGS Lake 01/23/97 350 -- F 25.5 244 -- ” S/cm, microsiemens per centimeter at 25 25 at centimeter per microsiemens S/cm, ” deep, Caballo Rd., Leesburg USGS Lake 12/12/96 350 -- F 22.0 287 -- µ ” deep nearLady Lake USGS Lake 01/07/97 203 -- F 24.4 170 -- freeflowSR off 46A nearSorrento USGS Lake 11/22/96 -- -- F 23.0 369 -- deep near CiskyPark, Leesburg USGS Lake 01/09/97 155 94 F 23.9 241 -- ” ” deep, 30845 CR435, Mt. Plymouth USGS Lake 01/14/97 154 126 F 23.7 282 .1 ” ” deep, Gourd Lake USGS Lake 01/15/97 -- -- F 22.1 321 -- ” shallow L-0378,Lake Norris Rd. SJRWMD Lake 11/02/93 33 28 S 24.9 160 -- deep nearCassia USGS Lake 01/27/97 -- -- F 23.0 407 <.1 ” ” C, degreeCelsius; o ber Map num- Site identification, well construction information, and water-quality data from the surficial aquifer system and the Upper Flor Upper the and system aquifer surficial the from data water-quality and information, construction well identification, Site Site Site number identification 285233081284502 129285301081285401 130 L-0716 Reese 4 SJRWMD Lake 11/29/98 37 22 S 24.1 189 -- 285318081340601 131 Eustis Sand Co. 12 285144081475001 125285144081475002 126285152081542901 4 Leesburg Fire Tower 127 deep L-0290 Leesburg Fire Tower 285230081242201 City of Fruitland Park,Cales Mem. RecreationComplex, deep 128 USGSRiver State Lower Preserve Wekiva 2 Lake 03/05/97 300 SJRWMD Lake 150 11/02/93 F 400 24.0 190 235 F -- 24.0 242 -- 285419081552801 133285425081323401 City deep of Lady Tower L-0594 Lake Water 134 USGS 2 SJRWMD Lake 11/03/93 180 160 F 23.6 200 -- 284813081294001284830081522401 106 107284856081383001 L-0436284922081494001 110 City of Leesburg, PS #6 deep, CanalSt. L-0592 284929081294901 111 CityDora of Mt20 112 L-0452 Abandoned 10 285037081342002 120285037081342003 SJRWMD 121 L-0704 Lake285057081243201 L-0714285118081391001 122 123 11/02/93 L-0032 16 City of EustisWaterplant 390 58 F SJRWMD Lake 23.4 SJRWMD 01/13/92 Lake285549081530601285551081293601 137 353 138 Carlton ParkCommunity 09/11/96 Village 10 -- -- B. Rogers4 SJRWMD 180 SJRWMD -- Lake Lake SJRWMD 41 08/26/98 F Lake 11/15/98 F 300 10/19/94 -- -- 280 120 ------F 96 -- -- S 24.2 F -- 25.2 132 21.9 -- 372 3,160 -- -- 285452081563201 135 Rowley 5 R. P. 284757081543002 102 4 C. R. Williams 284933081255801284936081475501 113 114 L-0038 Lake-Sumter Community College QW 2 285454081241201 136River State Lower Preserve Wekiwa 2 SJRWMD Lake 08/21/95 92 78 F 22.6 321 -- 284757081320701 101 L. Knowles 4 285028081253301 119 Seminole State Forest 4 284732081495301 99 Frog Leg Ln 4 284725081361901 98 6 Sink (LCWA) Wolf 284528081530201 88 Church Of Godof Prophecy 3 Water Management District; USGS, U.S. Geological Survey. Aquifer: F, Upper FloridanManagement aquifer; S,Aquifer: District; surficialU.S. USGS, aquifer GeologicalWater F, system. Survey. n Map Appendix. Appendix. liter; per milligrams [mg/L,

40 Ground-Water Quality of the Surficial Aquifer System and the Upper Floridan Aquifer, Ocala National Forest and Lake County, Florida Dis- lated lated calcu- (mg/L) solved solids, Dis- total total (mg/L) solved solids, Silica Silica (mg/L)

) 4 idan aquifer--Continued idan (mg/L as SO as Sulfate (mg/L) Chloride Chloride sium sium Potas- (mg/L) umbersshownfigures in 5 and 6] (mg/L) Sodium Sodium sium (mg/L) Magne- (mg/L) Calcium Calcium P) C;than; <, less--, unknown or not analyzed. Collecting agency: LC, LakeCounty; St.River Johns SJRWMD, phate phate Phos- o (mg/L as plus plus as N) (mg/L (mg/L Nitrite nitrate nitrate plus organic nitrogen nitrogen Ammonia (mg/L as N) (mg/L as ) 3 as (mg/L Bicar- bonate CaCO S/cm, microsiemens per centimeter at 25 25 at centimeter per microsiemens S/cm, ) µ 3 CaCO (mg/L as Alkalinity Alkalinity pH dard dard (stan- units) C, degree Celsius; o ber Map num- Site identification, well construction information, and water-quality data from the surficial aquifer system and the Upper Flor Upper the and system aquifer surficial the from data water-quality and information, construction well identification, Site Site number identification 284528081530201284725081361901 88284732081495301 98284757081320701 99 7.9284757081543002 101 7.8 102 7.5284813081294001 112 7.8284830081522401 106 8.0 --284856081383001 116 107 137 125284922081494001 -- 110 133284929081294901 7.7 111 142 -- 153 7.9 112 --284933081255801 -- 162284936081475501 -- 7.8 113 -- 111 --285028081253301 114 <.20 .26285037081342002 7.7 119 -- -- 100285037081342003 -- -- 135 7.9 120 -- 121 7.3 <.02 -- 169 .36285057081243201 122 8.6 116285118081391001 ------122 7.8 -- <.20 200285144081475001 206 123 .30 .12 .08285144081475002 -- 142 51 125 7.4 -- 134285152081542901 244 8.0 126 -- <.02 -- 43 -- 127 6.2 36 -- -- .05 158285230081242201 62 164 8.5 -- 34285233081284502 -- 7.7 128 .06 -- <.20285301081285401 1.2 -- -- 193 129 11 45 ------285318081340601 -- 130 7.3 ------108285419081552801 32 7.6 -- 131 6.8 <.02 -- -- 3.5 133 7.5 ------5.3 52 175 5.0285425081323401 -- 132 7.7 ------285452081563201 3.9 -- -- 9.6 19 134 8.1 .03 -- 143285454081241201 214 .3 135 41 .23 5.3 123285549081530601 9.0 .6 6.4 136 <.02 -- .22 ------161 23285551081293601 174 7.3 .6 137 7.8 58 .20 ------150 5.6 138 7.5 35 2.3 .26 -- .9 6.2 .31 8.9 7.9 40 -- -- .74 -- -- 1.1 -- 67 7.2 7.5 -- -- 4.6 <.20 .02 178 2.1 21 33 11 5.1 8.8 <.20 .04 8.2 102 <.02 1.0 146 -- 232 -- 12 155 82 ------217 .5 -- <.02 6.0 -- -- 9.5 124 15 29 <.02 4.3 .20 4.6 .06 58 .6 9.8 7.8 .4 189 11 8.2 12 5.4 -- -- .06 1.3 .25 -- 33 144 7.0 .46 1.2 .01 39.3 4.5 94 2.1 -- 8.8 -- -- 430 148 7.5 .8 448 11 -- 1.3 125 53 11 31 136 4.0 .02 <.02 156 8 31 6.5 58 -- 111 -- 1.5 285 21 14 6.2 .46 12 -- 7.4 166 -- 8.5 129 2.1 18 1.0 -- 178 -- 111 18 .11 -- 4.8 120 5.7 8.6 6.2 2.5 159 695 2.2 -- 202 31 9.6 -- -- 4.5 151 -- .21 -- 43 5.6 78 -- 10 202 2.5 8.0 251 11 6.6 13 4.3 -- 224 1,426 13 -- 5.1 17 -- 4.4 1,426 1 17 36 181 240 212 19 7.2 4.9 -- 1 -- 44 136 -- -- 3.6 4.4 9.2 -- 181 .74 7.1 100 7.9 80 9.6 132 9 4.3 12 2,022 214 -- 59 8.5 24 .38 -- 2.5 6.6 3.2 2,022 12 4.2 10 214 58 3.7 2.9 59 136 -- 4.8 5.9 5.8 10 .4 -- 150 136 130 6.5 .8 720 16 3.4 .6 19 10 -- 8.0 130 71 32 790 150 8.0 11 258 8.8 3 126 140 96 22 237 9.2 4.3 103 131 2.8 96 14 540 12 103 77 11 587 94 77 152 178 157 83 181 Water Management District; USGS, U.S. Geological Survey. Aquifer: F, Upper Management Floridanaquifer;District;surficial S, Aquifer: USGS,aquiferF, U.S.GeologicalWater system.MapSurvey. n Appendix. Appendix. liter; per milligrams [mg/L,

Appendix 41 Dis- (mg/L) solved oxygen S/cm) tance µ ( Specific conduc- ) C o ture ( Water tempera- idan aquifer--Continued idan Aquifer (feet) length length Casing Well land land (feet depth below below surface) umbers shown in figures 5 and 6] of of Date sample County agency Collecting C; <, lessC; than; unknown --, not or analyzed. Collectingagency: LC,St.Johns Lake River County; SJRWMD, o deep USGS Lake 02/19/97 100 -- F 23.5 1,330 -- ” freeflow USGS Lake 11/19/98 87 83 F 21.4 324 -- ” deep M-0046 USGS Marion 02/19/97 198 -- F 22.5 278 -- ” deep,near SR 19 Altoona USGS Lake 12/19/96 200 -- F 21.4 170 -- ” deep, Lake Mack Rd. USGS Lake 01/15/97 -- -- F 22.2 416 -- deep USGS Lake 02/28/97 -- -- F 23.1 234 -- ” deep, SR 42near Altoona USGS Marion 01/16/97 134 -- F 22.5 335 -- ” ” Site name shallow L-0702, Ocala NF USGS Lake 05/01/97 45 25 S 23.4 94 -- shallow, FSR 550 shallow, USGS Marion 05/19/97 40 30 S 22.5 35 -- ” ” irrigation deep, 40324 CR 439 USGS Lake 01/06/97 180 84 F 22.7 356 -- deep L-0385 near Lake Yale USGS Lake 01/23/97 -- -- F 21.9 241 -- ” deep USGS Marion 02/27/97 147 -- F 22.3 157 -- deep USGS Marion 02/27/97 166 -- F 22.2 144 -- S/cm, microsiemens per centimeter at 25 25 at centimeter per microsiemens S/cm, ” int. flow, Will Murphy Will Rd.int. flow, near Paisley USGS Lake 01/15/97 140 65 F 20.7 348 -- ” ” ” µ deepL-0059 nearCrows Bluff deepL-0400 nearCrows Bluff SJRWMD USGS Lake Lake 04/18/95 11/22/96 170 250 153 F -- F 23.1 889 24.0 -- 863 -- ” ” freeflow nearCrows Bluff USGS Lake 01/06/97 -- -- F 21.5 360 -- shallow near Alexander Springs, Paisley Rd. Paisley Springs, Alexander near shallow USGS Lake 12/07/98 23 18 S 23.5 63 5.1 shallow, FSR 573, 0.8shallow, mi W of FSR 523 USGS Marion 12/17/98 28 23 S 23.6 152 7.8 shallow, FSR 573, FSR0.4miE of FSR 566 shallow, USGS Marion 12/18/98 70 60 S 26.1 39 8.2 shallow near River Forest pumphouse, FSR 541 USGS Lake 12/17/98 20 10 S 23.3 46 -- ” deep, Emeralda Island USGS Lake 01/09/97 180 100 F 22.7 447 -- ” ” ” ” ” shallow L-0699,near LakeYale SJRWMD Lake 04/18/97 80 60 S 23.9 281 -- ” C, degreeCelsius; o ber Map num- Site identification, well construction information, and water-quality data from the surficial aquifer system and the Upper Flor Upper the and system aquifer surficial the from data water-quality and information, construction well identification, Site Site Site number identification 290436081383101290445081344001 180 181 RailroadGrade Rd. 2 AlexanderSprings Recreation Areasupply 4 290425081350801 179 Ocala NF 2 290300081471701 176 Ocala NF 2 290300081452001 175 Big Scrub Camp 6 290026081244701 157290038081491901 158 River Forest deep, FSR 541 near Forest Hills290043081232801 M-0233290047081232501 159 160290047081243401 River Forest2 161290050081381201 River Forest3 162 L-0638 Lake Dorr Recreation Area 4 USGS Lake 02/28/97 52 48 SJRWMD F Marion 04/27/90 22.0 SJRWMD 340 Lake 375 05/19/93 ------S -- -- F ------290155081332401 167 Bunch Ground Pond 4 290208081250201290220081485001 168290228081382301 169 St. Francis 2 290300081391801 171 Doe Lake Camp 6 173290300081420901 LCFD, District 4 - Station 6, 4 174573 FSR USGS shallow Ocala NF 2 USGS Marion 12/21/98 60 50 S 23.2 35 5.5 290002081483501290025081244801 155 156 M-0254 Ocala NF 2 SJRWMD Marion 08/19/91 81 71 S 23.7 496 -- 285908081470101 148285933081324001 BigBass Lake Recreation Area 4 152285934081262501 Paisley deep Fire Tower 153 LCFD(District 2 Station2) 4 USGS Lake 01/15/97 -- -- F 15.7 119 -- 285930081430901 150 Ocala Forest Campground 6 285810081234101 145River St. Preserve Lower 4 Wekiva 285618081491101 141285628081400501285659081470901 142 G. Davis 4 143 City of Umatilla PS Blanding deep L-0595 USGS 4 USGS Lake 03/05/97 450 137 F 23.3 238 -- 285606081353601 140 Coates FarmTree 4 285602081344301 139 K. Kruckenberg 4 285707081441101 144 IrvineEstate 4 J. F. Water Management District; USGS, U.S. Geological Survey. Aquifer: F, Upper FloridanManagement aquifer; S,Aquifer: District; surficialU.S. USGS, aquifer GeologicalWater F, system. Survey. n Map Appendix. Appendix. liter; per milligrams [mg/L,

42 Ground-Water Quality of the Surficial Aquifer System and the Upper Floridan Aquifer, Ocala National Forest and Lake County, Florida Dis- lated lated calcu- (mg/L) solved solids, Dis- total total (mg/L) solved solids, Silica Silica (mg/L)

) 4 idan aquifer--Continued idan (mg/L as SO as Sulfate (mg/L) Chloride Chloride sium sium Potas- (mg/L) umbersshownfigures in 5 and 6] (mg/L) Sodium Sodium sium (mg/L) Magne- (mg/L) Calcium Calcium P) C;than; <, less--, unknown or not analyzed. Collecting agency: LC, LakeCounty; St.River Johns SJRWMD, phate phate Phos- o (mg/L as plus plus as N) (mg/L (mg/L Nitrite nitrate nitrate plus organic nitrogen nitrogen Ammonia (mg/L as N) (mg/L as ) 3 as (mg/L Bicar- bonate CaCO S/cm, microsiemens per centimeter at 25 25 at centimeter per microsiemens S/cm, ) µ 3 CaCO (mg/L as Alkalinity Alkalinity pH dard dard (stan- units) C, degree Celsius; o ber Map num- Site identification, well construction information, and water-quality data from the surficial aquifer system and the Upper Flor Upper the and system aquifer surficial the from data water-quality and information, construction well identification, Site Site number identification 285602081344301285606081353601 139285618081491101 140285628081400501 141 7.8285659081470901 142 7.4 143 7.5 172285707081441101 8.0 175285810081234101 -- 144 138285908081470101 210 145 100285930081430901 214 7.4 148285933081324001 168 150 7.7 22 122 152 7.2 -- 104285934081262501 7.2 -- 164290002081483501 153 8.2 27 -- 137290025081244801 127 155 139290026081244701 .56 200 -- 7.3 156290038081491901 167 -- 44 157 8.8 -- 170 -- 158 4.4 -- 210290043081232801 7.2 .02 -- -- 54290047081232501 -- 159 ------290047081243401 256 160 -- -- 3 -- -- 187290050081381201 -- 161 6.5290155081332401 -- 162 8.1 -- 49 ------228 -- 167 53 -- 4 176290208081250201 -- -- 7.3 60 28 -- 136290220081485001 11 168 5.2 -- --290228081382301 -- -- 215 169 -- 9.6 --290300081391801 -- 166 17 -- 92 171 7.5 7.4 -- .88290300081420901 7.0 13 173 8.2 32 7.5 174 7.6 54 ------8.1 112 168290300081452001 -- .34 -- 6.7 37 <.02 -- 6.3 6.4 -- 7.8 16290300081471701 63 175 5.7 40 8.4 1290425081350801 205 76 176 7.1 .8 --290436081383101 -- .17 12 -- 47 40 179 8.4 -- .22 1.2 9.7 1.1 -- 77290445081344001 10 -- 180 6.2 -- 83 5.9 9 10 93 181 4.5 -- 4.2 8.0 57 11 4.9 13 61 5.1 4.5 1.5 -- 4.6 -- -- 2.5 -- 59 7.6 -- 72 12 11 1.2 2.8 -- -- 1 -- 1.1 4 1.2 .8 74 74 -- 13 5.4 4.9 <.20 .5 6 .8 72 -- 83 69 9.8 -- -- 5.0 2.0 -- -- .8 18 28 93 -- 14 4 6.8 -- 52 12 -- 4.3 14 101 .6 .25 -- 7 7.3 6.5 21 -- 4.2 28 22 .6 .25 23 ------208 1.6 198 2.9 <.20 156 -- 4.6 .02 7.3 270 .2 .2 -- 17 -- 101 -- -- 53 204 8.8 .5 8.7 199 -- .10 99 .2 -- 128 11 7.3 .01 263 <.02 16 1.0 3.7 5.4 16 7.4 155 22 140 4.2 -- 9.4 -- 7.6 -- .1 5.0 64 .02 -- 13 11 3.7 .01 -- 182 10 155 129 4.2 .8 189 .5 .1 148 5.7 8.2 28 .1 180 -- 9.6 17 .7 183 -- 15 190 9.7 2.5 <.1 153 -- 4.2 39 .7 1.8 60 4.3 3.4 1.0 230 190 15 9.8 7.9 .05 6.9 294 50 3.0 1.5 1.5 8.4 1.6 50 <.1 67 .8 243 14 -- 14 3 .6 295 236 29 .7 2.8 17 23 -- 6.7 5.5 .4 13 3.4 .6 216 1.5 550 3 5.4 10 -- 170 454 .4 2.1 1.7 1.8 3.2 .2 550 4.4 -- 10 -- 3.6 533 142 4.9 1 23 4.6 13 60 .1 4.1 <.1 -- 190 125 9.8 10 310 -- 15 34 3.4 94 25 207 7.3 6.4 96 80 -- 9 <1 67 2.1 1.4 4.3 25 83 8.4 25 96 72 34 1.9 710 75 72 14 19 836 <1 Water Management District; USGS, U.S. Geological Survey. Aquifer: F, Upper Management Floridanaquifer;District;surficial S, Aquifer: USGS,aquiferF, U.S.GeologicalWater system.MapSurvey. n Appendix. Appendix. liter; per milligrams [mg/L,

Appendix 43 Dis- (mg/L) solved oxygen S/cm) tance µ ( Specific conduc- ) C o ture ( Water tempera- idan aquifer--Continued idan Aquifer (feet) length length Casing Well land land (feet depth below below surface) umbers shown in figures 5 and 6] of of Date sample County agency Collecting C; <, lessC; than; unknown --, not or analyzed. Collectingagency: LC,St.Johns Lake River County; SJRWMD, o deep USGS Marion 01/21/97 206 -- F 22.8 101 -- ” deep USGS Lake 06/17/98 152 135 F 23.1 244 <.1 ” deep USGS Marion 02/27/97 -- -- F 22.1 188 -- deep USGS Marion 02/27/97 -- -- F 21.9 211 -- ” ” freeflownear Astor USGS Lake 11/22/96 146 135 F 22.0 6,900 -- ” Site name deepL-0045 SJRWMD Lake 08/14/91 254 204 F 23.4 2,850 -- ” deep L-0040 SJRWMD Lake 11/04/93 171 143 F 21.8 325 -- deep L-0066 SJRWMD Lake 07/18/95 102 74 F 23.6 1,308 -- ” ” S/cm, microsiemens per centimeter at 25 25 at centimeter per microsiemens S/cm, µ deep, near Moss Bluff USGS Marion 01/07/97 -- -- F 22.2 238 -- ” deepL-0407, Sellers Lake USGS Lake 02/26/97 -- -- F 22.9 273 -- ” shallow, near USStation Naval Tracking shallow, USGS Marion 05/19/97 40 30 S 22.0 50 -- shallow, FSR 584 FSRof W Bombing US Range shallow, USGS Marion 04/29/97 60 50 S 23.0 26 -- shallow M-0412,ofNaval US S Bombing Range USGS Marion 04/30/97 75 65 S 23.0 61 -- shallow, nearAlexander shallow, Springs Wilderness USGS Lake 05/21/97 30 20 S 22.6 46 -- ” ” ” ” deepM-0049, 19SR and SR 40 USGS Marion 09/12/96 166 166 F 22.5 239 -- deep, Tomahawk Lake deep, near Tomahawk Lynne USGS Marion 01/07/97 150 105 F 22.8 227 -- ” ” deep L-0455 USGS Lake 12/01/98 150 100 F 22.8 410 <.1 ” C, degreeCelsius; o ber Map num- Site identification, well construction information, and water-quality data from the surficial aquifer system and the Upper Flor Upper the and system aquifer surficial the from data water-quality and information, construction well identification, Site Site Site number identification 290839081313401 220290910081360001290913081313301 222 L-0430 223290940081313001 Camp McQuarrie (4-H Club Foundation)6 226 L-0333290947081313801 L-0434 227290950081315501291002081330601 228 L-0429 230291002081330603 Astor (A.G. Edwards) 6 231291015081385001 Astor 6 234 L-0460 DOT 496 SJRWMD Lake SJRWMD SJRWMD Lake 09/11/90 Lake SJRWMD 09/11/90 Lake 09/11/90 -- USGS 09/12/90 ------Lake -- -- F 12/07/98 -- F -- 30 F -- F -- 20 ------S ------24.5 ------67 <.1 290835081383001 217 Ocala NF 2 290820081305001 215 AlcoFish Camp (Frank Saul)2 290647081342102290650081314001 207 208290703081553901 L-0456290805081540801 209 Johnson deep, Levy Grant near Astor 214 M-0343 D. Craft4 USGS Lake 11/22/96 -- SJRWMD Lake SJRWMD -- Marion 03/01/94 06/14/94 F 32 -- 19.5 22 383 -- S -- F 21.6 -- 88 ------290647081342101 206 Alexander Springs 4 290633081375201290646081314001 202 203290646081314002 Camp Ocala6 204290646081442801 L-0441 205 L-0446 Ocala NF 2 SJRWMD SJRWMD Lake Lake 02/03/97 02/03/97 113 -- 104 -- F S ------290624081483901290628081425301 200 201 M-0211 Ocala BombingNF Lookout Range 4 Tower USGS Marion 12/11/98 69 57 S 23.4 53 7.3 290554081390501290613081402901 197 198 Buck LakeRecreation Area handpump 4 Farles Lake Recreation Area handpump 4 290508081550301290512081542301 187290526081493701 190 M-0339 192 M-0331290531081423101 L. Schrimsher 4 193 Ocala NF 4 SJRWMD SJRWMD Marion Marion 11/18/92 09/08/92 203 200 109 -- F F ------290452081320001 185 Ocala NF 2 290451081344401 184 Alexander Springs 4 Water Management District; USGS, U.S. Geological Survey. Aquifer: F, Upper FloridanManagement aquifer; S,Aquifer: District; surficialU.S. USGS, aquifer GeologicalWater F, system. Survey. n Map Appendix. Appendix. liter; per milligrams [mg/L,

44 Ground-Water Quality of the Surficial Aquifer System and the Upper Floridan Aquifer, Ocala National Forest and Lake County, Florida Dis- lated lated calcu- (mg/L) solved solids, Dis- total total (mg/L) solved solids, Silica Silica (mg/L)

) 4 idan aquifer--Continued idan (mg/L as SO as Sulfate (mg/L) Chloride Chloride sium sium Potas- (mg/L) umbersshownfigures in 5 and 6] (mg/L) Sodium Sodium sium (mg/L) Magne- (mg/L) Calcium Calcium P) C;than; <, less--, unknown or not analyzed. Collecting agency: LC, LakeCounty; St.River Johns SJRWMD, phate phate Phos- o (mg/L as plus plus as N) (mg/L (mg/L Nitrite nitrate nitrate plus organic nitrogen nitrogen Ammonia (mg/L as N) (mg/L as ) 3 as (mg/L Bicar- bonate CaCO S/cm, microsiemens per centimeter at 25 25 at centimeter per microsiemens S/cm, ) µ 3 CaCO (mg/L as Alkalinity Alkalinity pH dard dard (stan- units) C, degree Celsius; o ber Map num- Site identification, well construction information, and water-quality data from the surficial aquifer system and the Upper Flor Upper the and system aquifer surficial the from data water-quality and information, construction well identification, Site Site number identification 290451081344401290452081320001 184290508081550301 185290512081542301 187 7.7290526081493701 190 5.4 -- 192290531081423101 -- 83290554081390501 193 7.4 7290613081402901 197 101290624081483901 -- 198 6.1 114290628081425301 -- 200 7.9 9 201 8.0 --290633081375201 -- 139 13 6.2 102290646081314001 -- 202 6.7290646081314002 -- 90 203 16290646081442801 124 204 7.8 ------290647081342101 -- .05 37 205 -- 110 -- 206 131 --290647081342102 5.5 ------45290650081314001 -- .03 -- 207 7.4 --290703081553901 -- -- 160 208290805081540801 -- 10 209 5.6 -- 56 --290820081305001 -- -- 214 7.4 ------215 ------290835081383001 12 -- 7.7 -- 22 196290839081313401 7.9 217 2.2 ------290910081360001 -- 220 39 -- -- 107290913081313301 -- -- 239 -- 222 5.1 -- -- 166 -- --290940081313001 1.2 -- 223 9 -- 131 226 7.7 30 .34 -- -- 1.1 4.6290947081313801 ------5 -- 26 2.9290950081315501 3.4 ------227 11 .41 108291002081330601 -- 228 -- 3.8 5.6 .3 .10 --291002081330603 -- 359 -- 11 230 -- -- 7 1.0291015081385001 5.3 -- -- 132 -- 7.4 231 36 -- -- .02 ------10 234 6.9 1.0 4.2 76 -- -- 4.5 -- 3.6 6.7 -- 3.0 ------7.7 ------9 <.20 -- 208 -- -- 6.4 1.1 -- -- 1.3 53 .3 3.4 5.3 -- 5 -- 4.0 6.0 -- 254 .6 80 -- <.02 ------4.0 1.0 5.8 5.0 57 -- 5.0 -- .7 -- 8.4 -- 7.6 821 1.0 .7 4.7 6 -- 98 22 5.5 32 -- .08 1.1 -- 17 -- -- .26 13 -- -- .6 .1 2.7 821 6.8 4.5 -- -- 400 -- 4.5 -- 30 37 .1 -- 7.7 .29 6.6 <.02 .25 -- -- 146 13 -- 8.2 -- -- 130 3.9 .2 5 .02 .43 6.4 -- -- .6 3 11 2.8 128 -- -- <.02 3.6 2.0 -- .04 .05 930 .1 -- 128 7.7 -- 3.3 7.0 -- .8 .02 10 -- 38 .5 7.0 8.2 11 108 -- 70 .04 ------110 .6 -- 120 1.9 5.0 -- 9 8.9 .30 7.4 13 ------3.0 60 8.0 95 2,000 5.6 .6 2.7 -- 6.5 6.1 -- 48 23 -- 8.0 8.8 160 .1 8 39 -- <.1 -- 660 5.0 -- 1.4 1.8 8.4 5.1 3.9 360 -- 150 -- 184 7.4 26 11 8 9.8 1.0 -- -- 5.4 5.5 11 17 -- 184 -- 30 .8 11 -- <1 6.5 12 222 2.4 -- -- 4,980 764 -- .2 5 30 -- 128 700 8.6 216 222 4,447 2.0 .7 1,110 182 3.3 120 12 110 131 -- 40 .1 21 -- 186 28 131 3.4 -- 11 -- 12 -- 6.8 -- 6 -- 1,821 6.4 239 -- 1,821 8.7 -- -- 239 52 -- -- 124 -- 17 -- 128 Water Management District; USGS, U.S. Geological Survey. Aquifer: F, Upper Management Floridanaquifer;District;surficial S, Aquifer: USGS,aquiferF, U.S.GeologicalWater system.MapSurvey. n Appendix. Appendix. liter; per milligrams [mg/L,

Appendix 45 Dis- (mg/L) solved oxygen S/cm) tance µ ( Specific conduc- ) C o ture ( Water tempera- idan aquifer--Continued idan Aquifer (feet) length length Casing Well land land (feet depth below below surface) umbers shown in figures 5 and 6] of of Date sample County agency Collecting C; <, lessC; than; unknown --, not or analyzed. Collectingagency: LC,St.Johns Lake River County; SJRWMD, o deep USGS Marion 01/06/98 215 -- F 21.9 356 <.1 ” deep M-0153 USGS Marion 02/21/97 201 -- F -- 584 -- ” deep USGS Marion 02/21/97 -- -- F 21.7 204 -- ” freeflownear Ocala USGS Marion 09/19/96 135 135 F 23.2 344 -- ” deep M-0036 USGS Marion 09/13/96 165 85 F 21.8 385 -- ” Site name deep near Silver Glen Springs USGS Lake 01/14/97 -- -- F 22.8 18,200 -- deep near Silver Glen Springs USGS Lake 02/04/97 -- -- F 22.8 956 -- ” ” S/cm, microsiemens per centimeter at 25 25 at centimeter per microsiemens S/cm, freeflow M-0317 nearLisk Point, LakeGeorge USGS Marion 09/12/96 -- -- F 22.6 911 -- deep (SCE-123) USGS Marion 01/15/97 288 -- F 21.5 286 -- deep M-0044 USGS Marion 09/18/96 205 46 F 21.5 386 -- shallow M-0045 USGS Marion 09/18/96 10 2 S 24.2 27 -- µ ” ” ” ” deep M-0021 nearSalt Springs USGS Marion 09/11/96 298 268 F 22.9 897 -- ” freeflow (SCE-154) near Silver Springs USGS Marion 09/24/98 -- -- F 23.6 621 <.1 shallow, FSR 47 &47 FSR43 FSR shallow, USGS Putnam 05/16/97 70 60 S 22.9 30 -- shallow M-0413 USGS Marion 01/09/98 75 60 S 22.9 46 3.1 shallow (M-0408),88B FSRFSR & 88 USGS Marion 01/09/98 55 35 S 23.0 26 7.8 shallow, SR19 entrance toGlen Silver shallow, Springs USGS Marion 05/06/97 60 50 S 25.3 75 -- shallow, Cemetary Rd. shallow, near OcalaNF Boundary ” USGS Marion 05/19/97 35 25 S 23.7 25 -- ” ” ” ” ” 3

deep, CR 314 nearSprings Salt USGS Marion 01/14/97 184 -- F 22.1 159 -- deep M-0024 nearSalt Springs USGS Marion 09/04/96 90 53 F 22.3 118 -- ” ” C, degreeCelsius; o ber Map num- Site identification, well construction information, and water-quality data from the surficial aquifer system and the Upper Flor Upper the and system aquifer surficial the from data water-quality and information, construction well identification, Site Site Site number identification 292240081483101 325 Grassy Pond Recreation Area handpump 4 292403081422901 354 Ocala NF 2 292053081393401292056081433901 311 312 M-0220292058081435101 M-0267292131081440601 313292200081510001 316 M-0226 319 M-0222 CE84 6 SJRWMD SJRWMD Marion Marion SJRWMD 01/29/90 SJRWMD 04/02/91 Marion Marion 143 06/26/92 43 01/29/90 124 -- 126 -- F -- 62 F -- F F ------291849081411401 309 Lake George 4 291728081390501 298291733081390301291739081390501 299 Ponderosa Club 2 291750081392801 301 M-0136 305 M-0326291750081494001 M-0253291751081414301 306 307 CE-56 6 Ocala NF 4 SJRWMD SJRWMD Marion SJRWMD Marion 06/26/92 Marion 06/27/92 06/28/92 134 -- 106 -- -- F -- F -- F ------291657081461501 295 Ocala NF 4 291620081415001 294 Hopkin's Prairie Recreation Area handpump 4 291513081515601291600081550001 292 293 Lake Eatonhandpump Fore Lake RecreationArea CE55 4 USGS Marion 02/20/97 96 -- F 22.5 333 -- 291449081381701 288 Juniper (Hunt)Club 6 291448081381601 287 Juniper (Hunt)Club 4 291235081593801291440081384801 274 285 M-0271 Ocala NF 2 SJRWMD Marion 05/10/91 -- -- F ------291230081594001 273 Silver Run 291034081322101291051081495701 239 243 L-0627 Mill Dam Lake Recreation Areasupply 4 291117081540501 251 Redwater Lake 4 SJRWMD Lake 02/05/93 -- -- F ------291115081592501 250 Sharpes Ferry Marion, Silver Springs 6 291117081540502 252 Redwater Lake 4 291100081502001 245 Mill Dam Lake 6 291204081564801 261 Ocala NF 2 Water Management District; USGS, U.S. Geological Survey. Aquifer: F, Upper FloridanManagement aquifer; S,Aquifer: District; surficialU.S. USGS, aquifer GeologicalWater F, system. Survey. n Map Appendix. Appendix. liter; per milligrams [mg/L,

46 Ground-Water Quality of the Surficial Aquifer System and the Upper Floridan Aquifer, Ocala National Forest and Lake County, Florida Dis- lated lated calcu- (mg/L) solved solids, Dis- total total (mg/L) solved solids, Silica Silica (mg/L)

) 4 idan aquifer--Continued idan (mg/L as SO as Sulfate (mg/L) Chloride Chloride sium sium Potas- (mg/L) umbersshownfigures in 5 and 6] (mg/L) Sodium Sodium sium (mg/L) Magne- (mg/L) Calcium Calcium P) C;than; <, less--, unknown or not analyzed. Collecting agency: LC, LakeCounty; St.River Johns SJRWMD, phate phate Phos- o (mg/L as plus plus as N) (mg/L (mg/L Nitrite nitrate nitrate plus organic nitrogen nitrogen Ammonia (mg/L as N) (mg/L as ) 3 as (mg/L Bicar- bonate CaCO S/cm, microsiemens per centimeter at 25 25 at centimeter per microsiemens S/cm, ) µ 3 CaCO (mg/L as Alkalinity Alkalinity pH dard dard (stan- units) C, degree Celsius; o ber Map num- Site identification, well construction information, and water-quality data from the surficial aquifer system and the Upper Flor Upper the and system aquifer surficial the from data water-quality and information, construction well identification, Site Site number identification 291034081322101291051081495701 239291100081502001 243291115081592501 -- 245291117081540501 7.9 250 251 7.2291117081540502 7.7291204081564801 -- 96 252 6.9 142291230081594001 261 160291235081593801 5.1 273 117 196291440081384801 -- 173 274 5.2 195 285 7.4291448081381601 -- 239 3 --291449081381701 287 5.9 -- -- 8 134291513081515601 288 --291600081550001 292 7.5 4291620081415001 -- .47 163 14 7.0 293 -- 9 -- -- 294 7.6291657081461501 60 7.6 .13 17291728081390501 -- -- 91 295 7.3 .02 <.20 147291733081390301 -- -- 298 -- -- 186 73291739081390501 299 5.8 111 -- .05 172291750081392801 179 301 7.8 -- -- <.02 -- -- 227 305 25 --291750081494001 -- 210 -- 38 48 -- 3 --291751081414301 -- 65 306 .02 56 --291849081411401 -- -- 307 --292053081393401 7.7 -- .33 11 12 309 7.6 -- -- 4292056081433901 79 93 -- -- .88 14 6.2 311 ------312 8.3 -- --292058081435101 4.2 -- -- 35 .02 .7 4.2 19 <.02 7.1292131081440601 ------<.20 313 -- -- 8 .8 5.6292200081510001 -- -- 65 316 -- -- 43292240081483101 -- .6 319 -- -- 3.2 1 .13 .5292403081422901 -- <.02 .5 -- 325 -- -- 10 9.1 1 .5 79 -- -- 47 354 7.3 470 -- 1.4 7 8.4 -- 42 48 55 1,760 -- 2.1 -- .04 -- 7.4 -- 5.7 1.3 7.7 320 3.2 <.20 20 ------37 7.1 -- .20 298 -- 14 8.2 16 41 10 1.3 7.6 12 .1 3,100 ------.1 -- .4 -- <.1 9 100 45 -- .05 .1 -- -- 50 .10 48 170 .6 -- 3.2 5.9 -- 15 4.8 7.1 13 65 17 -- -- 11 .4 -- 3.8 .83 -- 36 3 ------.20 20 12 -- 6,000 -- -- 2.2 .7 15 .5 114 .9 154 200 1.2 -- 3.5 14 -- -- 200 -- 16 1,000 232 .3 ------.13 95 105 44 12 6.8 159 196 -- 10 -- 209 6.9 434 -- 7.2 6.5 -- -- 223 .2 92 5.3 -- 12 -- .1 -- -- 18 376 18 -- -- 8.8 3.6 .9 42 -- .1 -- -- 20 11,900 5 -- -- 4.4 9.1 8.6 170 -- 14 97 11,774 ------40 14 29 -- <1 -- -- 9.2 -- 1.3 28 110 -- 546 .3 -- .5 198 22 2.8 -- 3.4 1.2 186 220 -- 204 259 -- 593 14 -- 150 6.6 -- 105 7.8 4.6 180 9 189 223 204 3.4 64 .9 -- -- 26 88 -- 57 26 -- 3 88 -- 520 .2 3.1 257 -- -- <1 176 -- 564 2.2 -- 9.8 7.3 180 7.6 6.3 183 -- .2 134 120 100 99 -- 10 502 38 116 -- -- 4.6 -- 56 76 -- 17 555 -- 3 -- 8.2 2.2 -- 11 ------70 3.3 -- -- 313 -- 50 -- 24 352 -- <1 -- Water Management District; USGS, U.S. Geological Survey. Aquifer: F, Upper Management Floridanaquifer;District;surficial S, Aquifer: USGS,aquiferF, U.S.GeologicalWater system.MapSurvey. n Appendix. Appendix. liter; per milligrams [mg/L,

Appendix 47 Dis- (mg/L) solved oxygen S/cm) tance µ ( Specific conduc- ) C o ture ( Water tempera- idan aquifer--Continued idan Aquifer (feet) length length Casing Well land land (feet depth below below surface) umbers shown in figures 5 and 6] of of Date sample County agency Collecting C; <, lessC; than; unknown --, not or analyzed. Collectingagency: LC,St.Johns Lake River County; SJRWMD, o deep USGS Marion 02/25/97 165 96 F 22.0 854 -- ” Site name deep(P-0427) SJRWMD Putnam 02/28/94 148 95 F 22.7 141 -- ” S/cm, microsiemens per centimeter at 25 25 at centimeter per microsiemens S/cm, deep P-0472 nearWelaka shallow P-0473 near Welaka USGS USGS Putnam Putnam 12/08/98 12/08/98 144 45 -- -- F S 23.1 21.7 2,700 215 2.2 <.1 µ ” ” shallow, FSR 88 &88 FSR31 FSR shallow, USGS Marion 12/12/97 60 50 S 25.0 89 3.8 shallow, FSR 75 &75 FSR88 FSR shallow, USGS Marion 01/07/98 51 41 S 21.9 44 7.4 ” ” deep M-0410, FSR 88/31 USGS Marion 11/30/98 200 152 F 23.8 331 7.3 ” C, degreeCelsius; o ber Map num- SPRINGS Site identification, well construction information, and water-quality data from the surficial aquifer system and the Upper Flor Upper the and system aquifer surficial the from data water-quality and information, construction well identification, Site Site Site number identification 292817081483602 402 USGS 6 292817081483601 401 Ocala NF 2 292824081443301 405 Johnson's Field 4 292548081471201 382 Lake Delancy Recreation Areahandpump 4 292824081443302 406292948081503001 431292948081503002 Johnson's Field 4 432 USGSdeep P-0450, Rd.77-G 77 & USGS shallow P-0738, Rd. 77 & 77-G SJRWMD SJRWMD Putnam Putnam 03/06/95 03/06/95 241 102 215 92 F S 22.2 22.0 706 278 -- -- 292447081441401292447081441403 364 365292543081483201 SR19 near Frontier4 380 P-0820 Ocala NF 2 SJRWMD Putnam 11/08/94 60 40 S 22.7 130 -- 0223609528340008140510002243550 2284455081494100285102081263900 Apopka (Gourd Neck)Spring near Oakland 1 6 702237322 Alexander Springs Bluenear Springs, Yalaha Park Dr. 5285702081322400 Blueberry Spring, Seminole State Forest285702081322401 Blue Springs 9292618081412100 10284940081303800 Camp La-No-CheSprings vent 1 nearPaisley 12 8 Camp La-No-CheSprings vent 2 nearPaisley 13 Croaker Hole Spring nearWelaka 02236132 Bugg Spring USGS DrotySprings near Sorrento2844240814905000223610 16284740081251701 Lake Holiday Springs at Yalaha02235255 14 USGS 19 USGS 05/28/96 USGS Fern HammockSpring Falls Resort,Mastodon Wekiva Springs285105081263800 USGS 18284452081495400 Lake 22 Lake290220081260400 Juniper Springs 20 Lake 23 -- Moccasin Springs, SeminoleStateForest Lake285038081270100 24 Messant Spring 06/11/97 Mooring CoveSprings near Yalaha02236205 06/10/97 SJRWMD 27 Mosquito Springs, Alexander Springs 01/15/97Wilderness USGS 01/15/97 Palm Springs, SeminoleStateForest Lake ------Putnam USGS -- USGS 31 07/18/95 -- F USGS 11/12/98 Salt Springs -- Lake -- USGS Marion -- -- USGS USGS 26.0 Lake -- USGS -- 05/18/99 F 06/17/97 F Lake F Lake 06/10/99 Lake 241 USGS USGS F -- Lake -- 23.7 -- SJRWMD 06/16/97 -- 23.6 4.0 06/10/97 06/11/97 23.3 Marion Lake F -- 06/19/97 Lake 22.7 1,898 F 05/18/98 -- 283 USGS -- -- 408 06/17/97 -- -- 06/11/97 -- 414 23.9 -- -- USGS 1.0 F -- -- Marion -- F -- 1,084 ------F Lake 02/19/97 -- 2,510 -- 22.8 F 23.9 -- F F 05/24/95 -- -- 23.7 F -- -- 1,040 USGS 306 F 22.0 1,320 23.5 F 24.9 F 1.5 -- 24.0 -- -- Marion -- 278 2,850 -- 287 24.5 27.4 281 01/06/98 -- F -- -- 1,820 .5 352 <.1 128 F -- 21.8 -- -- .2 25.3 106 -- -- 677 F -- 23.7 6,190 2.4 Water Management District; USGS, U.S. Geological Survey. Aquifer: F, Upper FloridanManagement aquifer; S,Aquifer: District; surficialU.S. USGS, aquifer GeologicalWater F, system. Survey. n Map Appendix. Appendix. liter; per milligrams [mg/L,

48 Ground-Water Quality of the Surficial Aquifer System and the Upper Floridan Aquifer, Ocala National Forest and Lake County, Florida Dis- lated lated calcu- (mg/L) solved solids, Dis- total total (mg/L) solved solids, Silica Silica (mg/L)

) 4 idan aquifer--Continued idan (mg/L as SO as Sulfate (mg/L) Chloride Chloride sium sium Potas- (mg/L) umbersshownfigures in 5 and 6] (mg/L) Sodium Sodium sium (mg/L) Magne- (mg/L) Calcium Calcium P) C;than; <, less--, unknown or not analyzed. Collecting agency: LC, LakeCounty; St.River Johns SJRWMD, phate phate Phos- o (mg/L as plus plus as N) (mg/L (mg/L Nitrite nitrate nitrate plus organic nitrogen nitrogen Ammonia (mg/L as N) (mg/L as ) 3 as (mg/L Bicar- bonate CaCO S/cm, microsiemens per centimeter at 25 25 at centimeter per microsiemens S/cm, ) µ 3 CaCO (mg/L as Alkalinity Alkalinity pH dard dard (stan- units) C, degree Celsius; o ber Map num- SPRINGS Site identification, well construction information, and water-quality data from the surficial aquifer system and the Upper Flor Upper the and system aquifer surficial the from data water-quality and information, construction well identification, Site Site number identification 292447081441401292447081441403 364292543081483201 365292548081471201 380 8.2292817081483601 382 6.0 401 6.6292817081483602 8.2 --292824081443301 402 6.6 --292824081443302 15 405292948081503001 42 8.4 406 --292948081503002 37 431 7.8 -- 18 432 5.9 51 42 9.0 45 79 8.0 .20 70 .23 .25 51 -- -- 96 <.20 -- .02 85 .12 .58 <.20 ------<.20 -- .15 -- .24 .02 .20 -- -- .40 .07 23 -- <.02 4.6 4 .03 .02 7.9 .03 36 .97 .96 1.2 .15 20 .8 98 4.1 3.5 15 .01 28 -- 2.3 19 5.6 43 2.7 29 94 .68 2.3 .2 34 18 360 .3 .3 14 4.6 12 1.9 3.1 3 1 12 5 7.5 4.7 88 190 3.2 .4 93 16 64 720 1 13 73 1 20 4.4 160 21 5.3 6.4 11 65 177 8.4 1.3 38 42 9 9.1 65 57 36 480 58 25 2 40 1,680 189 57 527 31 1,724 8 152 188 6.9 113 431 153 431 153 0223609528340008140510002243550284455081494100 2285102081263900 1 6 8.202237322 7 5 7.8285702081322400 7.9285702081322401 74 7.5 7.5292618081412100 9 100 10 80284940081303800 12 90 8 7.7 -- 13 7.7 7702236132 122 98 7.9 7.9284424081490500 120 7.50223610 121 <.20 -- 94 16284740081251701 <.20 129 65 14602235255 -- 117 14 148 19 7.7 4.9 -- 157285105081263800 <.20 5.0 79 7.1 143 7.4 18284452081495400 105 -- 22 --290220081260400 .07 .03 20 23 <.02 7.8285038081270100 109 -- 128 .04 24 7.4 .24 -- --02236205 <.20 7.8 27 7.4 -- 29 .05 133 -- 7.4 .02 45 39 111 8.0 <.02 -- -- .46 <.20 104 130 46 .12 134 7.5 42 -- 31 135 55 -- -- 109 127 5.8 159 .08 4.1 .09 -- 7.4 163 23 -- .024 17 5.2 133 -- -- 58 41 4.3 48 -- 59 -- -- 74 .04 144 67 ------130 .9 14 <.20 11 15 -- .7 3 40 39 -- 82 .08 -- -- 3.5 12 -- -- 3.6 -- <.02 12 6.6 340 5.0 -- 6.2 307 6.5 .03 110 5.2 <.20 240 -- 8.6 .03 -- .04 -- 10 -- .9 13 69 1 5.9 .8 38 8.5 140 53 .8 100 .10 130 9.6 48 -- -- 10 670 11 47 210 7.1 4.4 51 10 .7 22 8.3 40 4 .03 142 9.6 150 6.9 74 -- 32 -- 174 14 340 4.3 78 2.4 160 6.1 5.4 129 180 578 676 7.1 9.6 157 100 400 12 7.9 10 5.4 10 -- -- 9 648 676 .2 12 6.5 1 6.5 1,410 1.2 230 940 1,203 620 246 176 150 .6 320 4.3 1,601 -- 11 254 10 1,204 15 238 380 172 26 155 11 320 242 6.3 8.2 240 -- 164 11 1,800 1,140 11 159 12 8.5 .5 410 12 829 -- 11 1,750 1,130 58 7.8 1,821 480 1,153 12 196 56 48 150 412 3,770 201 56 153 3,987 Water Management District; USGS, U.S. Geological Survey. Aquifer: F, Upper Management Floridanaquifer;District;surficial S, Aquifer: USGS,aquiferF, U.S.GeologicalWater system.MapSurvey. n Appendix. Appendix. liter; per milligrams [mg/L,

Appendix 49 Dis- (mg/L) solved oxygen S/cm) tance µ ( Specific conduc- ) C o ture ( Water tempera- idan aquifer--Continued idan Aquifer (feet) length length Casing Well land land (feet depth below below surface) umbers shown in figures 5 and 6] of of Date sample County LakeLakeMarion 02/04/97 06/17/97 06/06/97MarionMarion -- 03/03/99 -- -- 03/03/99 ------F -- F F -- 23.2 F 25.1 23.3 F 2,010 4,090 22.6 276 -- 22.7 -- 2,060 -- 1,640 5.4 6.0 agency Collecting USGS USGS USGS USGS USGS C; <, lessC; than; unknown --, not or analyzed. Collectingagency: LC,St.Johns Lake River County; SJRWMD, o Site name S/cm, microsiemens per centimeter at 25 25 at centimeter per microsiemens S/cm, µ s Tooth Spring, SeminoleTooth States Forest USGS Lake 06/12/97 -- -- F 22.4 768 -- ’ C, degreeCelsius; o ber Map num- Site identification, well construction information, and water-quality data from the surficial aquifer system and the Upper Flor Upper the and system aquifer surficial the from data water-quality and information, construction well identification, Site Site Site number identification 02235250285224081262400 34 Shark 33 Seminole Springs USGS Lake 05/24/95 -- -- F 24.3 335 -- 284437081491700291307081393600 39 40 Sun EdenSpring near Yalaha 292542081552600 Sweetwater Springs along Juniper Creek 292521081551200 41 44 PatchLanding Tobacco Spring Group1, Ocklawaha River Landings Springs, Ocklawaha Wells River 02236160 35 Silver GlenSprings Water Management District; USGS, U.S. Geological Survey. Aquifer: F, Upper FloridanManagement aquifer; S,Aquifer: District; surficialU.S. USGS, aquifer GeologicalWater F, system. Survey. n Map Appendix. Appendix. liter; per milligrams [mg/L,

50 Ground-Water Quality of the Surficial Aquifer System and the Upper Floridan Aquifer, Ocala National Forest and Lake County, Florida Dis- lated lated calcu- (mg/L) solved solids, Dis- total total (mg/L) solved solids, Silica Silica (mg/L)

Appendix 51