U.S. GEOLOGICAL SURVEY

Water-Resources Investigations Report 

Ground-Water Quality of the Surficial Aquifer 

System and the Upper Floridan Aquifer, 

Ocala National Forest and Lake County, 

Florida, 1990-99

Prepared in cooperation with the

Lake County Water Authority

St. Johns River Water Management District

Southwest Florida Water Management District

01–4008

By James C. Adamski and Leel Knowles, Jr.

Tallahassee, Florida

2001
U.S. DEPARTMENT OF THE INTERIOR

GALE A. NORTON, Secretary

U.S. GEOLOGICAL SURVEY

Charles G. Groat, Director

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

from:

U.S. Geological Survey

Branch of Information Services

Box 25286

Denver, CO 80225-0286

Phone: 1-800-ASK-USGS

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.

Additional information about water resources in Florida is available on the World Wide Web 

at http://fl.water.usgs.gov

District Chief

U.S. Geological Survey, WRD

Suite 3015

227 North Bronough Street

Tallahassee, FL 32301
Contents III

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
IV Contents

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 

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

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
Abstract 1

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

Data from 217 ground-water samples were 

statistically analyzed to assess the water quality 

of the surficial aquifer system and Upper Floridan aquifer in the Ocala National Forest and Lake 

County, Florida. Samples were collected from 

49 wells tapping the surficial aquifer system, 

141 wells tapping the Upper Floridan aquifer, and 

from 27 springs that discharge water from the 

Upper Floridan aquifer. A total of 136 samples 

was collected by the U.S. Geological Survey 

from 1995 through 1999. These data were 

supplemented with 81 samples collected by the 

St. Johns River Water Management District and 

Lake County Water Resources Management from 

1990 through 1998.

In general, the surficial aquifer system has 

low concentrations of total dissolved solids 

(median was 41 milligrams per liter) and major 

ions. Water quality of the surficial aquifer system, 

however, is not homogeneous throughout the 

study area. Concentrations of total dissolved 

solids, many major ions, and nutrients are greater 

in samples from Lake County outside the Ocala 

National Forest than in samples from within the 

Forest. These results indicate that the surficial 

aquifer system in Lake County outside the Ocala 

National Forest probably is being affected by 

agricultural and (or) urban land-use practices. 

High concentrations of dissolved oxygen (less 

than 0.1 to 8.2 milligrams per liter) in the surficial 

aquifer system underlying the Ocala National 

Forest indicate that the aquifer is readily 

recharged by precipitation and is susceptible to 

surface contamination.

Concentrations of total dissolved solids 

were significantly greater in the Upper Floridan 

aquifer (median was 182 milligrams per liter) than 

in the surficial aquifer system. In general, water 

quality of the Upper Floridan aquifer was homogeneous, primarily being a calcium or calciummagnesium-bicarbonate water type. Near the 

St. Johns River, the water type of the Upper Floridan aquifer is sodium-chloride, corresponding to 

an increase in total dissolved solids. Dissolvedoxygen concentrations in the Upper Floridan 

aquifer ranged from less than 0.1 to 7.3 milligrams per liter, indicating that, in parts of the 

aquifer, ground water is rapidly recharged by rainfall and is susceptible to surface contamination.

Median concentrations of nutrients in the 

Upper Floridan aquifer were not significantly 

different between the Ocala National Forest and 

the area of Lake County outside the Forest. The 

maximum nitrate concentration in the Upper 

Floridan aquifer in Ocala National Forest was only 

0.20 milligram per liter, whereas, 9 of 39 samples 

from the Upper Floridan aquifer in Lake County 

had elevated nitrate concentrations (greater than 

1.0 milligram per liter). Hence, nitrate concentrations of the Upper Floridan aquifer appear to be 

affected by land use in 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

INTRODUCTION

Ground water is an important resource in central 

Florida. Ground water from the Floridan aquifer system, particularly the Upper Floridan aquifer, is used 

extensively as a source of drinking water. Ground 

water, which discharges to lakes, springs, and streams 

throughout central Florida, also is used for agricultural, 

commercial, and industrial purposes. Hence, the quality of ground water is important for its numerous uses 

and for the aquatic environment of central Florida.

The ground water underlying large areas of central 

Florida, however, had not been studied recently. The 

most recent comprehensive hydrologic study of Lake 

County was published by Knochenmus and Hughes in 

1976. Because of recent growth in population, a comprehensive study of Lake County was needed to assess the 

current conditions of ground-water quality and to better 

understand the effects of land use on ground-water quality. A comprehensive hydrologic study of the Ocala 

National Forest (Ocala NF) was needed to document 

water quality in a relatively pristine area. This report is 

the compilation of results from two comprehensive 

investigations of the hydrology of the Ocala NF and the 

hydrology of Lake County. The objectives for this part of 

the two studies are to (1) describe current conditions of 

the ground-water quality of the Ocala NF and Lake 

County and (2) determine the natural and anthropogenic 

factors affecting ground-water quality.

The study area is in north-central Florida and 

includes all of Lake County and parts of Marion and Putnam Counties that lie within the Ocala NF (fig. 1). The 

study area includes numerous growing towns and communities including Clermont, Eustis, Tavares, Leesburg, 

Mount Dora, and Lady Lake in Lake County; and the 

communities of Lynne, Salt Springs, and Astor Park, 

which lie within the Proclamation Boundary (perimeter) 

of the Ocala NF. Agriculture, including citrus farming, 

nurseries (horticulture), and livestock, is an important 

land use in the study area, excluding the Ocala NF.

The Ocala NF is about 690 square miles (mi2) of 

relatively pristine second-growth forests. The Ocala NF, 

owned and operated by the U.S. Forest Service, has a 

sparse population and little anticipated population 

growth. Ground-water quality of the Ocala NF was not 

extensively studied prior to the current investigation. 

A comprehensive study of the Ocala NF was needed to 

describe the natural conditions of the ground-water 

quality of central Florida.

Lake County is about 1,150 mi2

 in area. Northeastern Lake County overlaps with the Ocala NF. The 

rest of Lake County is directly south of the Ocala NF 

(fig. 1). Lake County is directly west and northwest of 

metropolitan Orlando.

Purpose and Scope

The purpose of this report is to describe the 

ground-water quality of the Ocala NF and Lake County 

with regard to concentrations of major ions and nutrients. The report contains a brief description of the 

environmental setting of the study area, including 

climate, physiography, hydrogeology, and major land 

uses. The report also contains a description of datacollection and analytical methods. A discussion of the 

natural and anthropogenic factors affecting water quality of the surficial aquifer system and the Upper Floridan aquifer is included. This report is the result of two 

comprehensive studies of the water resources of Ocala 

NF and Lake County, Florida.

Previous Investigations

Fenneman (1938) described the topographic 

and geomorphic features of Florida. Cooke (1945) 

described the geomorphology, geology, and stratigraphy of Florida, and White (1970) further described the 

geomorphology of the Florida peninsula. Matson and 

Sanford (1913) and Stringfield (1933 and 1936) were 

the first to investigate the hydrogeology of Florida. 

Rosenau and others (1977) described the location, 

discharge, and water quality of numerous springs.

Later hydrogeologic investigations included the 

Regional Aquifer-System Analysis (RASA) of the 

Floridan aquifer system, in which the hydrogeologic 

framework of the Floridan aquifer system was 

described by Miller (1986). Tibbals (1990) simulated 

the ground-water flow in the Floridan aquifer system in 

east-central Florida using a model area that included 

most of the Ocala NF and Lake County.

Sprinkle (1989) described the geochemistry of 

the Floridan aquifer system. Katz (1992) investigated 

the geochemistry of the Upper Floridan aquifer 

throughout the State of Florida. Rutledge (1987) and 

German (1997) investigated the relation of land use and 

ground-water quality. German (1997) compared 

ground-water quality underlying areas of agricultural 

and urban land use in parts of Lake and Orange Counties to ground-water quality underlying parts of the 

Ocala NF. Toth (1999) investigated the geochemistry 

and isotopic composition of selected springs in the 

Ocala NF and Lake County.
Introduction 3

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

Florida, 1990-99

Faulkner (1973) described the hydrogeology of 

northwestern Ocala NF during a study for the crossFlorida barge canal. Phelps (1994) investigated the 

hydrogeology and water quality of the Silver Springs 

basin, just west of Ocala NF. Knowles (1996) estimated evapotranspiration of the Silver Springs basin. 

Knochenmus and Hughes (1976) investigated ground 

water, surface water, and water quality of Lake County. 

Murray and Halford (1996) simulated ground-water 

flow in parts of Lake County. Few other studies of 

the water resources of the Ocala NF or Lake County 

are available.

Acknowledgments

The authors are grateful to the St. Johns River 

Water Management District, Southwest Florida Water 

Management District, and Lake County Board of Commissioners for information and hydrologic data made 

available for this investigation. Personnel at the U.S. 

Forest Service assisted with site access, data collection, 

and information. Finally, the authors are grateful to 

land and well owners for access to sites.

ENVIRONMENTAL SETTING

The study area has a subtropical climate characterized by hot humid summers and mild winters. The 

mean annual air temperature is 70.7 degrees Fahrenheit (o

F) (National Oceanic and Atmospheric Administration (NOAA), 1992). Minimum air temperatures 

during the winter months occasionally drop below 

freezing, but rarely are less than 20 o

F. Maximum air 

temperatures during the summer months are commonly greater than 90 o

F, and occasionally exceed 

100 oF locally. 

Average precipitation (from 1961 to 1990) 

ranges from about 52 inches per year (in/yr) in Ocala 

to less than 51 in/yr in Clermont (NOAA, 1992). The 

average precipitation for the entire study area is slightly 

more than 51 in/yr. Annual precipitation can vary 

greatly from the average, ranging from a minimum of 

32 inches (in.) in 2000 to a maximum of 71 in. in 1964. 

Typically, more than half of the precipitation occurs 

during the summer as isolated thunderstorms and from 

tropical systems. The remainder of the precipitation 

generally occurs during winter months from frontal 

systems. A large part of precipitation is balanced by 

evapotranspiration. For example, in 1998, precipitation 

in the study area was about 57 in., about 35 in. of which 

were balanced by evapotranspiration.

Physiography

Land-surface elevations in the Ocala NF and 

Lake County range from less than 10 feet (ft) to more 

than 300 ft above sea level. The highest point in the 

Florida peninsula (312 ft) is located on the north end 

of the Lake Wales Ridge in Lake County (fig. 2) 

(Knochenmus and Hughes, 1976). Topography of 

the study area ranges from flat-lying lands to gently 

rolling hills.

The study area is located in the Central Highlands topographic division (Cooke, 1945) and contains 

three basic land forms—ridges, valleys, and uplands 

(fig. 2). Parts of the Mount Dora and the Lake Wales 

Ridges are located in the study area. These ridges, 

which are quasi-linear features, are a series of gently 

rolling hills that trend northwest-southeast with elevations ranging from 100 to more than 300 ft above sea 

level. The two ridges are parallel and separated by the 

Central Valley, an area of relatively low relief and landsurface elevations (White, 1970). In addition to the 

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 

the study area contain gently rolling hills with elevations ranging from 50 to 200 ft. above sea level (White, 

1970; Knochenmus and Hughes, 1976).

In addition to these major land forms, numerous 

karst features including sinkholes, springs, and caves 

are present in the study area. Sinkholes are abundant 

along the flanks of the ridges and uplands of the study 

area. Sinkholes can be dry or water-filled internally 

drained depressions that commonly are areas of high 

recharge to the underlying aquifers.

Hydrology and Hydrogeology

Surface-water resources are abundant throughout most of the study area. Except for the southwestern 

corner of Lake County, most of the study area is 

drained by the St. Johns River and its tributaries. The 

St. Johns and Wekiva Rivers form the eastern boundaries of Lake County and the Ocala NF. The Ocklawaha River forms the northwestern part of the 

Proclamation Boundary of the Ocala NF. Smaller 

tributaries discharge surface and ground-water to the 

St. Johns and Wekiva Rivers. These tributaries include 

Alexander Springs Creek and Blackwater Creek.
Environmental Setting 5

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

Florida, 1990-99

Springs, which represent locations of groundwater discharge, are abundant, and possibly located 

along subsurface fracture systems of the Ocala Uplift 

(Faulkner, 1973). Most springs are located along or 

near the Ocklawaha, St. Johns, and Wekiva Rivers. 

A few small springs are located in central Lake 

County. Silver Springs is located just west of the study 

area, near the city of Ocala. Some of the larger springs, 

such as Alexander, Salt, and Silver Glen, issue from 

visible cavities or conduits formed from dissolution of 

the carbonate rock.

In addition to streams and springs, the study area 

is characterized by abundant lakes. These lakes range 

in size from small, water-filled sinkholes and depressions to large water bodies such as Lake Eustis, Lake 

Griffin, and Lake Harris in Lake County, and Lake 

Dorr and Lake Kerr in the Ocala NF (fig. 1). Furthermore, Lake Apopka and Lake George are present on 

the eastern boundaries of Lake County and the Ocala 

NF, respectively.

Wetlands also are abundant in the study area. 

Wetlands are present along major streams and the perimeters of the lakes. The Green Swamp is a wetland area 

that covers a large part of southern Lake County (fig. 1).

Much of the Mount Dora Ridge in the Ocala NF 

is drained internally through sinkholes and depressions. Streams are noticeably absent from the area. 

Runoff in this area probably is minimal, with most of 

the precipitation being balanced by evapotranspiration 

and ground-water recharge.

Lithologic descriptions of well cuttings, borehole geophysical logs, and well completion reports 

were analyzed to describe the extent, thickness, and 

lithology of the major hydrogeologic units in the study 

area. These hydrogeologic units include the surficial 

and Floridan aquifer systems (fig. 3).

The surficial aquifer system consists of unconsolidated, siliclastic sediments of Pliocene through 

Recent age. The sediments are primarily quartz sand, 

but locally, the aquifer also contains silt, clay, chert, 

shell, or organic deposits that range in thickness from 

less than 25 to more than 100 ft. In general, these 

sediments are thicker under the Mount Dora and Lake 

Wales Ridges than under adjacent areas.

The surficial aquifer system is recharged primarily by precipitation. Ground water in the surficial 

aquifer system flows laterally to discharge into streams 

and lakes, and vertically to recharge the underlying 

Upper Floridan aquifer. The elevation of the water 

table in the surficial aquifer system ranges from near 

sea level along the St. Johns River to more than 165 ft 

above sea level in areas underlying the Mount Dora 

Ridge. The elevation of the water table in the surficial 

aquifer system can fluctuate greatly within a short 

time, particularly in areas of higher elevation. For 

example, the water-table elevation in one surficial well 

located in the northern part of the Ocala NF (number 

401 in appendix) increased more than 8 ft from 

September 1997 to May 1998.

Figure 3. Geologic and hydrogeologic units in the study area (modified from Tibbals, 1990).
Environmental Setting 7

The Floridan aquifer system is separated from 

the overlying surficial aquifer system by the intermediate confining unit (fig. 3). The intermediate confining unit consists primarily of clay, silt, and carbonate 

units of Miocene age, but can include clay units of 

Pliocene through Pleistocene age where these younger 

units are vertically continuous. Thickness of the intermediate confining unit ranges from less than 20 ft to 

more than 100 ft.

The Floridan aquifer system consists of a thick 

sequence of carbonate rocks of Eocene age (fig. 3) that 

is divided into the Upper Floridan and Lower Floridan 

aquifers (Tibbals, 1990). This study focused primarily 

on water quality in the Upper Floridan aquifer because 

(1) the Upper Floridan aquifer is the primary source of 

drinking water in the area, (2) the Upper Floridan aquifer is more susceptible to contamination than the Lower 

Floridan aquifer, and (3) data available for the Lower 

Floridan aquifer are sparse.

The depth to the top of the Ocala Limestone, 

which generally coincides with the top of the Upper 

Floridan aquifer, averages from less than 100 ft to more 

than 200 ft throughout most of the study area (Tibbals, 

1990). Just west of the study area, near the city of Ocala 

and along parts of the Ocklawaha River upstream of 

Lake Ocklawaha, the Ocala Limestone is exposed at 

land surface; in areas of northeast Lake County, and 

near Lake George, the Ocala Limestone is within 50 ft 

of land surface.

Locally, the range of depth to the top of the 

Upper Floridan aquifer can be large. Information from 

geologic and geophysical well logs indicate that the 

depth to the top of the Upper Floridan aquifer can 

range several hundred feet over relatively small (less 

than a mile) spatial distances. The top of the Upper 

Floridan aquifer probably is rather hummocky as a 

result of dissolution of the carbonate rocks. Although 

many of these dissolution features are buried by clastic 

deposits in a type of terrain known as mantled karst, 

sinkholes, springs, and caves present in parts of the 

study area result from, and are indicative of, carbonaterock dissolution.

The Upper Floridan aquifer is recharged primarily by downward leakage from the surficial aquifer 

system through the intermediate confining unit. This 

recharge can be rapid in places with abundant sinkholes or where the intermediate confining unit is thin 

or breached by collapse into underlying dissolution 

cavities. Just west of the study area, near the city of 

Ocala and in Sumter County, the Upper Floridan 

aquifer is within 25 ft of land surface. Hence, in these 

areas, recharge probably occurs rapidly from precipitation, which could allow the aquifer to be susceptible 

to surface contamination.

Water levels in the Upper Floridan aquifer range 

from near sea level in the St. Johns River basin to more 

than 100 ft above sea level in southern Lake County. 

Ground water generally flows northward in southern 

Lake County, and northeastward elsewhere in the 

study area (Sepulveda, 1997; Merritt, 1998; Adamski, 

1998). In the Ocala NF, ground-water flow generally 

is from the west and southwest toward Lake George 

(fig. 4). Discharge from the Upper Floridan aquifer 

occurs in areas where the potentiometric surface is 

higher than the water table of the surficial aquifersystem—at springs, from flowing wells, and by slow 

leakage through the intermediate confining unit into 

the surficial aquifer system.

Land and Water Use

Land use in the Ocala NF primarily consists of 

relatively pristine forests and wetlands that are designated as multi-use lands and managed for recreational 

use and silviculture. In 1994, second-growth pine and 

hardwood forests accounted for 65 percent, and water 

and wetlands accounted for 19 percent of the land use 

(Agustin Sepulveda, U.S. Geological Survey (USGS), 

written commun., 2000). A U.S. Naval bombing range 

occupies an area of about 9 mi2 in the south-central 

part of the Ocala NF (fig. 1), and is not open to the 

general public.

 Land use within the Ocala NF Proclamation 

Boundary ranges from wilderness to residential. Land 

administered by the U.S. Forest Service covers about 

89 percent of the area contained by the Proclamation 

Boundary. Of the land owned by the U.S. Forest Service, more than 71 percent is used for timber management/harvest, about 7 percent for wilderness, about 

1 percent for U.S. Navy bombing practices, less than 

1 percent for recreational sites, and about 20 percent is 

used as transportation corridors and access roads 

(2,300 miles) (Richard B. Shellfer, U.S. Forest Service, 

oral commun., 1999). Several communities (Astor, 

Astor Park, Lynne, Paisley, and Salt Springs) are 

located along or within the Proclamation Boundary of 

the Ocala NF and account for about 11 percent of the 

land is private residential. Although mining currently is 

not practiced in the Ocala NF, a few small claypits are 

used for road maintenance within the forest area.
8 Ground-Water Quality of the Surficial Aquifer System and the Upper Floridan Aquifer, Ocala National Forest and Lake County, 

Florida, 1990-99

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).
Data Collection and Analysis 9

Land use in Lake County is a mixture of agriculture, forests, rangeland, urban, open water, and wetlands. The percentages of these land uses, however, 

have changed over time. For example, agriculture 

(predominantly citrus) was about 43 percent of the land 

use in 1977, but was less than 30 percent of the land use 

in 1994. The decrease in agriculture during this period 

was related to several severe winter freezes, which had 

adverse effects on the citrus industry. Other types of 

land use increased from 1977 to 1994 as a result of the 

decrease in agricultural land use (Agustin Sepulveda, 

USGS, written commun., 2000). For example, forest 

increased from 15 percent to 18 percent, rangeland 

from 2 to 7 percent, and urban from 4 to 6 percent. 

Urbanization of Lake County has been rapidly increasing in recent years. Population of Lake County has 

increased from 86,720 in 1975 to an estimated population of 206,500 in 2000 (Richard L. Marella, USGS, 

written commun., 2000). Hence, present (2000) urban 

land use in Lake County probably is greater than 6 percent. Water and wetlands have remained constant since 

1977 at nearly 36 percent of the land use (Agustin 

Sepulveda, USGS, written commun., 2000).

Nearly all water withdrawn from the Ocala NF is 

from the Upper Floridan aquifer and is used for domestic and recreation use. Numerous private residences are 

distributed within the Proclamation Boundary of the 

Ocala NF. In 1998, residences and recreation sites used 

nearly 2 million gallons per day (Mgal/d) of ground 

water and returned about 60 percent to the ground-water 

system by septic systems (Richard Marella, USGS, 

written commun., 2000; Brian McGurk, St. Johns 

River Water Management District (SJRWMD), written 

commun., 1999).

Lake County obtains most of its water from the 

Upper Floridan aquifer. In 1998, Lake County pumped 

more than 100 Mgal/d. Agricultural land use accounts 

for more than 50 percent; municipal, domestic, and 

recreation use accounts for nearly 40 percent; and commercial/industrial use accounts for less than 10 percent 

of the total water pumped. Currently, about 40 percent 

of all water pumped from the Upper Floridan aquifer in 

Lake County is estimated to be returned to the groundwater system by land application and by septic systems 

(Richard Marella, USGS, written commun., 2000; 

Brian McGurk, SJRWMD, written commun., 1999).

DATA COLLECTION AND ANALYSIS

Water-quality data from springs and wells in 

Ocala NF and Lake County were compiled to assess 

current ground-water quality conditions in the study 

area. The assessment included collection of waterquality samples, compilation of existing data, and 

statistical analysis of the final data set.

Water-quality samples were collected by the 

USGS from 1995 through 1999. Samples were collected from wells and springs located in the Ocala NF 

and (or) Lake County; locations are shown in figures 5 

and 6, respectively. The number of samples collected 

in the forest and county areas and where these two 

areas overlap is listed in table 1. A total of 23 samples 

were collected from wells in the surficial aquifer system, 25 samples were collected from springs, and 

88 samples came from wells in the Upper Floridan 

aquifer (figs. 5 and 6, table 1, appendix).

Existing data were compiled from samples 

collected by the SJRWMD and the Lake County Water 

Resources Management. These samples were collected 

from wells and springs located in the Ocala NF and (or) 

Lake County, and are shown in figures 5 and 6, respectively. A total of 26 samples were collected from wells 

in the surficial aquifer system (fig. 5, table 1). Two samples were collected from springs (fig. 6) and 53 samples 

from wells in the Upper Floridan aquifer (fig. 5, table 1, 

appendix). The samples analyzed and evaluated for this 

study were collected after 1990; samples collected prior 

to 1990 were not considered representative of current 

ground-water conditions, especially outside the relatively undeveloped Ocala NF.

Table 1. Number of water-quality samples from wells and 

springs in the Ocala National Forest and Lake County, 

Florida

[USGS, U.S. Geological Survey; SJRWMD, St. Johns River Water 

Management District; Ocala NF, Ocala National Forest (outside of Lake 

County); Lake, Lake County (outside of Ocala National Forest); Overlap, 

area of Ocala National Forest within Lake County]

Collecting 

agency

Aquifer and 

site type

Ocala

NF Lake Overlap Total

USGS 

(1995-99)

Surficial aquifer 

system, wells

17 1 5 23

Upper Floridan 

aquifer, wells

26 48 14 88

Upper Floridan 

aquifer, springs

8 15 2 25

SJRWMD 

and Lake 

County 

(1990-98)

Surficial aquifer 

system, wells

4 20 2 26

Upper Floridan 

aquifer, wells

13 29 11 53

Upper Floridan 

aquifer, springs

0 112
10 Ground-Water Quality of the Surficial Aquifer System and the Upper Floridan Aquifer, Ocala National Forest and Lake County, 

Florida, 1990-99

Figure 5. Location of wells with water-quality data.
Data Collection and Analysis 11

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

Florida, 1990-99

Water samples from wells were collected by the 

USGS using either an existing submersible pump or a 

portable 2-inch diameter stainless steel submersible 

pump with silicone tubing. Field measurements of temperature, pH, and specific conductance were made on 

ground-water samples at all sites. Dissolved oxygen 

also was measured in the field. Samples were collected 

after purging the well of at least three casing volumes 

and (or) after stabilization of the field measurements. 

Samples from springs were collected from inside the 

orifice either with sample bottles or a churn splitter and 

processed using a peristaltic pump with silicone tubing. 

Samples were filtered using a 0.45-micrometer poresize disposable capsule filter. All samples were analyzed for major ions (calcium, magnesium, sodium, 

potassium, sulfate, and chloride), alkalinity, and total 

dissolved solids; bicarbonate concentrations were calculated from alkalinity. Samples for cation analysis 

were acidified with nitric acid to adjust the pH to less 

than 2. Samples for nutrient analysis [nitrite plus nitrate 

as nitrogen (hereafter referred to as “nitrate” because 

nitrite generally was below detection limits), Kjeldahl 

nitrogen (ammonia plus organic nitrogen as nitrogen), 

and phosphate] were chilled and delivered overnight to 

the USGS laboratory in Ocala, Florida.

Some sites were sampled more than once over a 

period of several years. Only the most recent, analytically 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. Calcium, 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 available for 71 samples. Data used in this report are shown 

in the appendix.

Simple linear regression indicated that total dissolved solids (TDS) concentrations of samples from 

both aquifers were significantly correlated to specific 

conductance (r 2

>0.99) (fig. 7). If TDS concentrations 

were not available, TDS was calculated as a function 

of specific conductance using the following equation:

TDS = -27 + 0.65(specific conductance).

Results plotted in figure 7 illustrate that the correlation 

was not as good for samples with specific conductance 

less than 100 microsiemens per centimeter.

The non-parametric Kruskal-Wallis test was 

used to statistically identify differences in water quality between the aquifers, between site types (springs 

and wells), and between geographic locations (Helsel 

and Hirsch, 1992). For statistical purposes, samples 

from sites located in the area of overlap between the 

Ocala NF and Lake County (table 1) were grouped 

with sites in the Ocala NF because land use in this area 

of northern Lake County is similar to the rest of the 

Ocala NF. Medians of groups of data are assumed 

significantly different from one another if the probability (p-value) is less than 5 percent (<0.05) that the 

difference occurs by chance. The non-parametric 

Spearman’s rho (r) rank correlation coefficient was 

used to determine monotonic relations between waterquality variables.

Figure 7. Relation of concentrations of total dissolved solids 

to specific conductance in ground-water samples from the 

surficial aquifer system and the Upper Floridan aquifer.
Ground-Water Quality 13

GROUND-WATER QUALITY 

The Ocala NF is a relatively pristine area. Hence, 

the ground-water quality conditions of the Ocala NF 

probably approximate the natural ground-water quality 

of north-central Florida. As noted, the land use of Lake 

County is primarily a mixture of agriculture, forest, and 

rangeland with increasing urbanization. The compilation of data from these two areas allows for the comparison of water quality with respect to land use.

Surficial Aquifer System

Ground water in the surficial aquifer system 

generally has low concentrations of major ions and total 

dissolved solids. The water type of the surficial aquifer 

system is laterally diverse; results indicate that in places 

the ground water in the surficial aquifer can be calcium 

bicarbonate, sodium-chloride, or mixed cation and 

mixed anion (figs. 8 and 9). TDS concentrations of 

all samples ranged from 3 to 356 milligrams per liter 

(mg/L), with a median of 41 mg/L (table 2, fig. 10). 

More than 75 percent of the samples had TDS concentrations less than 100 mg/L. None of the samples had 

concentrations that exceeded the National Secondary 

Drinking Water Regulations (NSDWR) for TDS 

(500 mg/L), chloride (250 mg/L), or sulfate (250 mg/L). 

NSDWRs are non-enforceable drinking water standards 

issued for taste or aesthetic purposes (U.S. Environmental Protection Agency, 2000). Water in the surficial aquifer system is slightly acidic, with a pH of 6.1 or less in 

50 percent of the samples (table 2). Three samples had a 

pH of 4.5 or less. Furthermore, pH was significantly 

correlated to concentrations of TDS (r = 0.64). In 18 of 

19 samples with pH less than or equal to 6.0, TDS 

concentrations were less than or equal to 60 mg/L.

The median TDS concentrations in the surficial 

aquifer system is significantly greater (p = 0.01) in 

samples from Lake County (96 mg/L) than in samples 

from the Ocala NF (36 mg/L). In addition, median pH 

and concentrations of calcium, magnesium, potassium, bicarbonate, and sulfate in the surficial aquifer 

system are significantly greater (p<0.01, <0.01, 

<0.01, <0.01, <0.01, and 0.04, respectively) in samples from Lake County than in samples from the 

Ocala NF (figs. 11 and 12). pH and concentrations of 

sulfate, chloride, and total dissolved solids (fig. 10) in 

the surficial aquifer system are lowest in the central 

part of the Ocala NF and increase toward the St. Johns 

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]

Constituent Units

Lake County Ocala National Forest

Number

 of 

samples

Minimum Median Maximum

Number

 of 

samples

Minimum Median Maximum

Specific conductance μS/cm 19 47 190 590 26 25 52 496

pH standard 

units

15 5.0 6.4 7.9 26 4.4 5.8 8.8

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

Florida, 1990-99

Figure 8. Relative concentrations of calcium, magnesium, and sodium in samples from wells tapping 

the surficial aquifer system.
Ground-Water Quality 15

Figure 9. Relative concentrations of bicarbonate, sulfate, and chloride 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

Figure 10. Concentrations of total dissolved solids in samples from wells tapping the surficial aquifer system.
Ground-Water Quality 17

Dissolved oxygen is abundant in the surficial 

aquifer system underlying the Ocala NF. Nine samples 

had dissolved-oxygen concentrations ranging from 3.1 

to 8.2 mg/L; only two samples had dissolved-oxygen 

concentrations less than 0.1 mg/L. Dissolved-oxygen 

data were not available for any samples collected from 

Lake County.

Concentrations of nutrients in the surficial aquifer system generally are low. Nitrate concentrations in 

samples from the Ocala NF range from less than 0.02 

to 1.6 mg/L with a median of 0.1 mg/L (table 2, fig. 13). 

None of the samples had nitrate concentrations that 

exceeded the Maximum Contaminant Level (MCL) of 

10 mg/L (U.S. Environmental Protection Agency, 

2000). Nitrogen constituents (nitrate and Kjeldahl 

nitrogen) were detected in 67 percent of the samples. 

The low median concentration probably is a result of 

the pristine, relatively undeveloped conditions in the 

area. Nitrate and Kjeldahl nitrogen were detected at 

higher concentrations and more frequently in the surficial aquifer system in Lake County than in the Ocala 

NF. Nitrate concentrations in Lake County range from 

less than 0.02 to 4.2 mg/L, with a median of 0.07 mg/L 

(figs. 13 and 14). Nitrate was detected in nearly 

80 percent of the samples, and Kjeldahl nitrogen was 

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.
18 Ground-Water Quality of the Surficial Aquifer System and the Upper Floridan Aquifer, Ocala National Forest and Lake County, 

Florida, 1990-99

Phosphate was greater than or equal to 0.02 mg/L 

in more than 85 percent of the samples. The source of 

phosphate in the aquifer could be anthropogenic or natural phosphatic sands in the surficial aquifer system and 

underlying Hawthorn Formation.

The water quality of the surficial aquifer system 

likely can be attributed to a number of factors including 

rainfall quality, the lithology of the aquifer, mixing of 

water from the surficial aquifer system with water discharging or leaking from the Upper Floridan aquifer, 

and effects of land use. Low concentrations of dissolved solids (less than 100 mg/L) probably originate 

in precipitation recharging the aquifer. Precipitation 

chemistry in peninsular Florida generally is acidic 

(pH ranging from about 4.5 to 5.0 in 1999) with 

concentrations of major ions generally less than 1 mg/L. 

For example, in 1999 calcium concentrations in rainfall 

ranged from 0.08 to 0.25 mg/L, sodium concentrations 

ranged from 0.14 to 0.33 mg/L, and chloride concentrations ranged from 0.26 to 0.58 mg/L (National Atmospheric Deposition Program, 2000). These ions are 

concentrated in the aquifer through evapotranspiration 

processes. The low pH and TDS of most samples in the 

Ocala NF indicate that the quartz-sand lithology of the 

surficial aquifer system is unreactive and does not 

significantly affect the geochemistry of the ground 

water. As previously noted, the surficial aquifer system 

in Lake County can contain clay and shell units that can 

Figure 12. Distribution of pH, bicarbonate, sulfate, and chloride in springs and in wells tapping the surficial aquifer system 

and the Upper Floridan aquifer.
Ground-Water Quality 19

contribute to the concentrations of major ions and TDS 

of the aquifer. However, the number of samples collected for analysis of most water-quality constituents of 

the surficial aquifer system in Lake County is 20 or 

less; hence, determining the primary factors affecting 

water quality is difficult.

An important process affecting water quality in 

the surficial aquifer system in the Ocala NF is mixing 

with water from the Upper Floridan aquifer. For example, water-level data from a pair of wells (405 and 406 

in fig. 5) near the northern boundary of the Ocala NF 

indicated that water levels were consistently higher in 

the Upper Floridan aquifer than in the surficial aquifer 

system. Hence, calcium-magnesium-bicarbonate water 

present in the surficial aquifer system at that location 

(figs. 8 and 9) could be the result of water discharging 

from the Upper Floridan aquifer upward into the 

surficial aquifer system.

The primary source of dissolved oxygen in 

ground water is precipitation that recharges the aquifer 

(Hem, 1989). Dissolved-oxygen concentrations in 

ground water generally decrease over time as the 

oxygen in the water reacts with minerals and organic 

material. Hence, the abundance of dissolved oxygen in 

the surficial aquifer system indicates rapid groundwater recharge and (or) the lack of reactive minerals in 

the aquifer. Rapid ground-water recharge can allow the 

aquifer to be susceptible to surface contamination.

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.
20 Ground-Water Quality of the Surficial Aquifer System and the Upper Floridan Aquifer, Ocala National Forest and Lake County, 

Florida, 1990-99

Figure 14. Nitrate concentrations in samples from wells tapping the surficial aquifer system.
Ground-Water Quality 21

Differences in water quality of the surficial 

aquifer system in Ocala NF and Lake County possibly 

is related to land use. Locally, nitrate concentrations in 

the surficial aquifer system are elevated. Nitrate concentrations are greater than 1.0 mg/L in two samples 

from Lake County and one sample from the Ocala NF 

(fig. 14). Nitrate concentrations greater than 1.0 mg/L 

in ground water generally are related to land-use practices, such as septic systems or land application of fertilizers. Hence, the water quality of the surficial aquifer 

system in parts of the study area could be affected by 

present and (or) past land use. Because constituents 

such as nitrate can remain in ground water for many 

years, elevated concentrations of nitrate in ground 

water do not necessarily indicate the effects of present 

land use, but could have resulted from previous landuse practices.

Applications of fertilizer and pumping water 

from the Upper Floridan aquifer to irrigate citrus 

groves in Lake County also could be increasing the pH 

and concentrations of major ions in the surficial aquifer 

system. Nitrate concentrations in the surficial aquifer 

system in Lake County were positively correlated to 

pH (r = 0.75); however, sample size was only 13 

(fig. 15). These results are in agreement with German 

(1997) who determined that concentrations of major 

constituents and nitrate in the surficial aquifer system 

were greater in areas underlying citrus groves in Lake 

and Orange Counties than in a forested area in the 

Ocala NF.

Upper Floridan Aquifer

Water throughout most of the Upper Floridan 

aquifer is a calcium-bicarbonate or calcium-magnesium-bicarbonate type (figs. 16 and 17). Concentrations of TDS were less than 250 mg/L in 77 percent of 

the samples collected throughout the study area. Near 

the St. Johns River and Lake George, TDS concentrations ranged from about 2,000 to nearly 12,000 mg/L 

(fig. 18). A total of 14 of 111 samples from wells had 

concentrations of TDS that exceeded the NSDWR of 

500 mg/L. A total of 14 of 135 samples had chloride 

concentrations that exceeded the NSDWR of 250 mg/L, 

and 5 of 131 samples had sulfate concentrations that 

exceeded the NSDWR of 250 mg/L.

In general, water-quality conditions and the 

concentrations of most major ions in the Upper Floridan aquifer do not differ significantly between samples 

collected in the Ocala NF and Lake County. In southern 

Lake County, the dominant cation was calcium, 

whereas further north in Lake County and the Ocala 

NF, the dominant cations were calcium and magnesium. Bicarbonate concentrations generally were 

greater in samples from wells in Lake County than in 

samples from the Ocala NF. Near the St. Johns and 

Wekiva Rivers, sodium, chloride, and sulfate were the 

dominant ions (figs. 16 and 17). This change to a 

sodium-chloride-sulfate water type corresponds to the 

increases in concentrations of sulfate, chloride, and 

TDS observed in these areas (figs. 18, 19, and 20).

Concentrations of most major ions and TDS 

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 

greater solubility of carbonate rocks in comparison to 

quartz sand. 

Figure 15. Relation of nitrate concentrations to pH in wells 

tapping the surficial aquifer system in Lake County, Florida.
22 Ground-Water Quality of the Surficial Aquifer System and the Upper Floridan Aquifer, Ocala National Forest and Lake County, 

Florida, 1990-99

Figure 16. Relative concentrations of calcium, magnesium, and sodium in samples from wells tapping 

the Upper Floridan aquifer.
Ground-Water Quality 23

Figure 17. Relative concentrations of bicarbonate, sulfate, and chloride 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 18. Concentrations of total dissolved solids in samples from wells tapping the Upper Floridan aquifer.
Ground-Water Quality 25

Figure 19. Sulfate 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

Figure 20. Chloride concentrations in samples from wells tapping the Upper Floridan aquifer.
Ground-Water Quality 27

Water-quality data were available from a total 

of 27 springs. In 8 of 10 springs within the Ocala NF, 

the water type is sodium-chloride or sodium-chloridesulfate (figs. 21 and 22). The water type of springs in 

central Lake County is calcium bicarbonate. Median 

concentrations of magnesium, sodium, potassium, 

sulfate, chloride, and total dissolved solids in samples 

from springs were significantly greater (p<0.01) than 

in samples from wells tapping the Upper Floridan 

aquifer (figs. 11 and 12). These results are probably 

related to the geographical distribution of springs and 

do not indicate significant hydrogeologic differences 

between springs and wells. Most springs are located in 

the discharge areas of the Upper Floridan aquifer near 

the St. Johns and Wekiva Rivers. As previously noted, 

the aquifer in this area has relatively high concentrations of sodium, chloride, and total dissolved solids. 

A comparison of samples from springs and nearby 

wells tapping the Upper Floridan aquifer indicates that 

both have similar geochemistry (figs. 16, 17, 21, and 22).

Dissolved-oxygen concentrations measured in 

samples from wells tapping the Upper Floridan aquifer 

ranged from less than 0.1 to 7.3 mg/L. Although the 

data are not evenly distributed geographically (fig. 23), 

the samples indicate that dissolved oxygen is present in 

parts of the Upper Floridan aquifer in the Ocala NF and 

Lake County. The presence of dissolved oxygen indicates relatively rapid recharge in some parts of the 

Upper Floridan aquifer.

Concentrations of nutrients generally are low in 

the Upper Floridan aquifer in the Ocala NF (table 3). 

Nitrate concentrations in samples ranged from less 

than 0.02 to 0.20 mg/L with a median of 0.03 mg/L 

(fig.13). In contrast, nitrate concentrations in samples 

from the Upper Floridan aquifer in Lake County 

ranged from less than 0.02 to 7.5 mg/L with a median 

of 0.02 mg/L (fig. 13, table 3). Kjeldahl nitrogen in the 

Upper Floridan aquifer ranged from less than 0.2 to 

0.88 mg/L in the Ocala NF, and from less than 0.2 to 

0.79 mg/L in Lake County. Phosphate ranged from 

0.01 to 0.13 mg/L with a median of 0.03 mg/L in samples from the Ocala NF. In samples from Lake County, 

phosphate concentrations were not significantly different, ranging from less than 0.01 to 0.14 mg/L with 

a median of 0.05 mg/L. 

Median concentration of Kjeldahl nitrogen was 

significantly greater (p<0.01) in samples from wells in 

the Ocala NF than in samples from springs (fig. 13). 

Concentrations of nutrients were not significantly 

different between samples from the surficial aquifer 

system and the Upper Floridan aquifer in either the 

Ocala NF or Lake County, possibly because of the 

paucity of data for the surficial aquifer system.

Similar to the surficial aquifer system, waterquality conditions of the Upper Floridan aquifer 

probably are related to the lithology of the aquifer, 

the mixing of fresh recharge water with saline water 

from deeper in the aquifer, and the effects of land use. 

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]

Constituent Units

Lake County Ocala National Forest

Number 

of 

samples

Minimum Median Maximum

Number 

of 

samples

Minimum Median Maximum

Specific conductance μS/cm 81 132 289 3,160 57 101 360 18,200

pH standard 

units

81 6.4 7.7 8.8 57 6.1 7.6 9.0

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

Florida, 1990-99

Figure 21. Relative concentrations of calcium, magnesium, and sodium in samples from springs discharging 

from the Upper Floridan aquifer.
Ground-Water Quality 29

Figure 22. Relative concentrations of bicarbonate, sulfate, and chloride in samples from springs discharging 

from 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

Figure 23. Concentrations of dissolved oxygen in samples from wells tapping the Upper Floridan aquifer.
Summary 31

The calcium-magnesium-bicarbonate water type of 

most samples indicates dissolution of the carbonate 

rocks that form the aquifer. The change in cation 

distribution from calcium to calcium-magnesium 

probably is related to an increase of dolomite in the 

carbonate sequence of the aquifer. The difference in 

bicarbonate concentrations between samples from the 

Ocala NF and Lake County also are related to the 

amount of dolomite in the sequence. Because dolomite is less soluble than limestone (Drever, 1988), a 

relatively larger amount of dolomite in the sequence 

would result in a lower concentration of bicarbonate. 

Nonetheless, the overall quality of water is similar 

between the Ocala NF and Lake County, and is indicative of the relatively homogeneous lithology of the 

Upper Floridan aquifer.

 The sodium-chloride water and high concentrations of TDS near the St. Johns River probably result 

from upward migration of saline water, probably relict 

sea water from high stands of sea level. The sodiumchloride water and high concentrations of TDS in the 

Upper Floridan aquifer are spatially isolated near the 

St. Johns River. Ground water east of the St. Johns 

River in Putnam and Volusia Counties is calcium bicarbonate with TDS concentrations less than 200 mg/L 

(Tibbals, 1990). Hence, lateral migration of saline 

water from the Atlantic Ocean is unlikely.

As in the surficial aquifer system, the presence of 

dissolved oxygen in the Upper Floridan aquifer indicates rapid recharge and (or) lack of reactive mineral 

constituents. In water from springs, the presence of dissolved oxygen indicates that shallow, rapidly recharging ground water is mixing with relict water from 

deeper in the aquifer, confirming the conclusions of 

Toth (1999). Hence, the presence of dissolved oxygen 

in parts of the Upper Floridan aquifer indicates that the 

aquifer is susceptible to surface contamination.

Water quality of the Upper Floridan aquifer 

appears to be affected by land use. For example, the 

maximum nitrate concentration in samples from wells 

in the Ocala NF is only 0.20 mg/L. Low concentrations of nutrients in the Upper Floridan aquifer in the 

Ocala NF probably are a result of the pristine, forested 

land use of the area. In contrast, nitrate concentrations 

were greater than 1.0 mg/L in 9 of 39 (23 percent) 

samples from wells in Lake County outside the Ocala 

NF (fig. 24). Hence, nitrate concentrations of the 

Upper Floridan aquifer appear to be related to land use 

in Lake County.

SUMMARY

This report describes water-quality conditions in 

the surficial aquifer system and the Upper Floridan 

aquifer underlying the Ocala National Forest and Lake 

County, Florida, from 1990-99. Data from two comprehensive water-resources studies, one of the Ocala 

National Forest and the other of Lake County, are 

presented. The study area, which contains numerous 

lakes, is drained by the St. Johns River and its tributaries. Numerous karst features are present in parts of the 

study area including sinkholes, springs, and caves. 

The surficial aquifer system, which is unconfined, is recharged by precipitation and discharges to 

nearby lakes and streams. The Upper Floridan aquifer 

is recharged by the surficial aquifer system either by 

slow leakage through the intermediate confining unit, 

or more rapidly in places where the intermediate confining unit is missing or breached. Discharge from the 

Upper Floridan aquifer occurs in places where the 

potentiometric surface is higher than the water table, at 

springs, flowing wells, and by diffuse leakage to the 

overlying surficial aquifer system.

As of 1994, land use in the Ocala National Forest 

consisted primarily of second-growth forests (65 percent), 

and water and wetlands (19 percent). In contrast, land use 

in Lake County was more diverse. In 1994, land use in 

Lake County was a mixture of agriculture (30 percent), 

forest (18 percent), rangeland (7 percent), urban (6 percent), and water and wetlands (36 percent). Population in 

Lake County has been increasing in recent years, and 

present (2000) urban land use probably is greater than 

6 percent.

Ground-water samples were collected by the 

U.S. Geological Survey from 23 wells tapping the 

surficial aquifer system, and from 25 springs and 

88 wells tapping the Upper Floridan aquifer. These 

data were supplemented with samples collected by the 

St. Johns River Water Management District and Lake 

County Water Resources Management from 26 wells 

tapping the surficial aquifer system, and from 2 springs 

and 53 wells tapping the Upper Floridan aquifer. Most 

samples were analyzed in the field for temperature, pH, 

and specific conductance, and in the laboratory for 

major ions (calcium, magnesium, sodium, potassium, 

sulfate, and chloride), alkalinity, and total dissolved 

solids. A total of 98 samples were analyzed for nitrite 

plus nitrate, 81 samples were analyzed for Kjeldahl 

nitrogen, and 71 samples for phosphate.

The data were statistically analyzed using 

non-parametric procedures to identify differences in 

water quality between the aquifers, between site types 

(springs and wells), and between geographic locations. 
32 Ground-Water Quality of the Surficial Aquifer System and the Upper Floridan Aquifer, Ocala National Forest and Lake County, 

Florida, 1990-99

Figure 24. Nitrate concentrations in samples from springs and from wells tapping the Upper Floridan aquifer.
Summary 33

Medians of groups of data were assumed significantly 

different from one another if the probability (p-value) 

was less than 5 percent that the difference occurs by 

chance.

Water type throughout most of the Upper 

Floridan aquifer is calcium-bicarbonate or calciummagnesium-bicarbonate. Near the St. Johns and 

Wekiva Rivers, however, sodium, chloride, and sulfate 

are the dominant ions. Total dissolved solids concentrations were low (less than 250 milligrams) throughout 

most of the aquifer, but increased to nearly 12,000 milligrams per liter near the St. Johns and Wekiva Rivers. 

Concentrations of most major ions and total dissolved 

solids are significantly greater in the Upper Floridan 

aquifer than in the surficial aquifer system. A total of 

14 of 111 samples had concentrations that exceeded the 

National Secondary Drinking Water Regulations for 

total dissolved solids, 14 of 135 samples had concentrations that exceeded the National Secondary Drinking 

Water Regulations for chloride, and 5 of 131 samples 

had concentrations that exceeded the National Secondary Drinking Water Regulations for sulfate.

The water type within the surficial aquifer system 

is laterally diverse, and can be calcium-bicarbonate, 

sodium-chloride, or mixed cations and mixed anions. 

Concentrations of major ions and total dissolved solids 

are generally low; total dissolved solids concentrations 

ranged from 3 to 356 milligrams per liter with a median 

of 41 milligrams per liter. None of the samples had concentrations of total dissolved solids, chloride, or sulfate 

that exceeded any National Secondary Drinking Water 

Regulations. In general, pH and concentrations of calcium, magnesium, potassium, bicarbonate, sulfate, and 

total dissolved solids in the surficial aquifer system are 

significantly greater in samples from Lake County than 

in samples from the Ocala National Forest.

Dissolved-oxygen concentrations in the surficial 

aquifer system in the Ocala National Forest ranged from 

less than 0.1 to 8.2 milligrams per liter. No data were 

available for the surficial aquifer system in Lake County.

Concentrations of nutrients in the surficial aquifer 

system in the Ocala National Forest generally were 

low—below 1.0 milligrams per liter in most samples. 

Nitrate and Kjeldahl nitrogen were detected more frequently in the surficial aquifer system in Lake County 

than in the Ocala NF.

Nitrogen concentrations are elevated in parts of 

the Upper Floridan aquifer outside the Ocala National 

Forest. Nitrate concentrations in samples ranged from 

less than 0.02 to 7.5 milligrams per liter, Kjeldahl 

nitrogen in samples ranged from less than 0.20 to 

0.88 milligram per liter, and phosphate ranged from 

less than 0.01 to 0.14 milligram per liter.

Dissolved oxygen is present in parts of the 

Upper Floridan aquifer. Concentrations ranged from 

less than 0.1 to 7.3 milligrams per liter. Dissolved 

oxygen present in the Upper Floridan aquifer indicates rapid ground-water recharge and (or) a lack of 

reactive mineral constituents. In springs, the presence 

of dissolved oxygen indicates a mixing of shallow, 

rapidly recharging ground water with the deep, connate sea water. The presence of dissolved oxygen in 

samples from springs and wells in the Upper Floridan 

aquifer indicates that the aquifer is susceptible to 

surface contamination.

Water-quality conditions probably can be 

attributed to a number of factors. Most water-quality 

differences between the surficial aquifer system and 

the Upper Floridan aquifer probably are related to differences in lithology. Calcium-magnesium-bicarbonate water type throughout most of the Upper Floridan 

aquifer results from the dissolution of the carbonate 

rocks, which form the aquifer. The high concentrations of sodium and chloride in the Upper Floridan 

aquifer near the St. Johns River probably result from 

the upward migration of saline water. Relatively high 

concentrations of sodium, chloride, and sulfate in 

samples from many of the springs probably are related 

to the geographical proximity of most springs to the 

St. Johns and Wekiva Rivers. Comparison of samples 

from springs and nearby wells tapping the Upper 

Floridan aquifer indicate similar geochemistry of both 

site types.

Water quality of the Upper Floridan aquifer also 

appears to be affected by land use. Nitrate concentrations were elevated (greater than 1 milligram per liter) 

in 9 of 39 samples (23 percent) collected from wells 

in Lake County. In contrast, nitrate concentrations in 

samples from the Upper Floridan aquifer in the Ocala 

National Forest did not exceed 0.20 milligram per 

liter.

In summary, the Ocala National Forest and Lake 

County contain abundant ground-water resources. 

These ground-water resources are important for 

agriculture, domestic and public supply, recreation, 

and for the aquatic ecology of the study area. The 

surficial aquifer system and Upper Floridan aquifer, 

however, are susceptible to surface contamination. 

Present and (or) past land uses in parts of Lake County 

could have affected the ground-water quality as indicated by elevated concentrations of nitrate. Further 

studies to better quantify the effects of land use 

on ground-water quality, particularly with respect 

to the rapid urbanization of parts of the study area, 

would be beneficial.
34 Ground-Water Quality of the Surficial Aquifer System and the Upper Floridan Aquifer, Ocala National Forest and Lake County, 

Florida, 1990-99

REFERENCES

Adamski, J.C., 1998, Potentiometric surface of the Upper 

Floridan aquifer in the St. Johns River Water Management District and vicinity, Florida, May 1998: U.S. 

Geological Survey Open-File Report 98-648, 1 sheet.

Cooke, C.W., 1945, Geology of Florida: Florida Geological 

Survey Bulletin 29, 339 p.

Drever, J.I., 1988, The geochemistry of natural waters (2d 

ed.): Englewood Cliffs, New Jersey, Prentice Hall, 

437 p.

Faulkner, G.L., 1973, Geohydrology of the Cross-Florida 

Barge Canal area with special reference to the Ocala 

vicinity: U.S. Geological Survey Water-Resources 

Investigations Report 1-73, 117 p.

Fenneman, N.M., 1938, Physiography of eastern United 

States: New York, McGraw-Hill Book Co., Inc., 714 p.

German, E.R., 1997, Analysis of nonpoint-source groundwater contamination in relation to land use: Assessment of nonpoint-source contamination in central 

Florida: U.S. Geological Survey Water-Supply Paper 

2381-F, 60 p. 

Helsel, D.R., and Hirsch, R.M., 1992, Statistical methods in 

water resources: Amsterdam, Elsevier Science Publishers, 522 p.

Hem, J.D., 1989, Study and interpretation of the chemical 

characteristics of natural water (3d ed.): U.S. Geological Survey Water-Supply Paper 2254, 263 p.

Katz, B.G., 1992, Hydrochemistry of the Upper Floridan 

aquifer, Florida: U.S. Geological Survey WaterResources Investigations Report 91-4196, 37 p.

Knochenmus, D.D., and Hughes, G.H., 1976, Hydrology of 

Lake County, Florida: U.S. Geological Survey WaterResources Investigation 76-72, 100 p.

Knowles, Leel, Jr., 1996, Estimation of evapotranspiration in 

the Rainbow Springs and Silver Springs basins in northcentral Florida: U.S. Geological Survey WaterResources Investigations Report 96-4024, 37 p.

Matson, G.C., and Sanford, Samuel, 1913, Geology and 

ground waters of Florida: U.S. Geological Survey 

Water-Supply Paper 319, 445 p.

Merrit, M.L., 1998, Potentiometric surface of the Upper 

Floridan aquifer in the St. Johns River Water Management District and vicinity, Florida, September 1997: 

U.S. Geological Survey Open-File Report 98-183, 

1 sheet.

Miller, J.A., 1986, Hydrogeologic framework of the Floridan 

aquifer system in Florida and in parts of Georgia, 

Alabama, and South Carolina: U.S. Geological Survey 

Professional Paper 1403-B, 91 p.

Murray, L.C., Jr., and Halford, K.J., 1996, Hydrogeologic 

conditions and simulation of ground-water flow in the 

greater Orlando metropolitan area, east-central Florida: 

U.S. Geological Survey Water-Resources Investigations Report 96-4181, 100 p.

National Atmospheric Deposition Program, 2000, Annual 

and seasonal data summary for site FL03 [cited October 

2, 2000] http://nadp.sws.uiuc.edu/ads/FL03.pdf.

National Oceanic and Atmospheric Administration, 1992, 

Monthly station normals of temperature, precipitation, 

and heating and cooling degree days 1961-1990: in

Climatography of the United States No. 81 (by State) 

for Florida, Asheville, N.C., 26 p.

Phelps, G.G., 1994, Hydrogeology, water quality, and potential for contamination of the Upper Floridan aquifer in 

the Silver Springs basin, central Marion County, 

Florida: U.S. Geological Survey Water-Resources 

Investigations Report 92-4159, 69 p.

Rosenau, J.C., Faulkner, G.L., Hendry, C.W., Jr., and Hull, 

R.W., 1977, Springs of Florida (2d ed.): Florida Bureau 

of Geology Bulletin 31, 461 p.

Rutledge, A.T., 1987, Effects of land use on ground-water 

quality in central Florida--Preliminary results: U.S. 

Geological Survey Toxic Waste--Ground-Water Contamination Program: U.S. Geological Survey WaterResources Investigations Report 86-4163, 49 p.

Sepulveda, Nicasio, 1997, Potentiometric surface of the 

Upper Floridan aquifer in the St. Johns River Water 

Management District and vicinity, Florida, May 1997: 

U.S. Geological Survey Open-File Report 97-572, 

1 sheet.

Sprinkle, C.L., 1989, Geochemistry of the Floridan aquifer 

system in Florida and in parts of Georgia, South Carolina, and Alabama: U.S. Geological Survey Professional Paper 1403-I, 105 p.

Stringfield, V.T., 1933, Ground water investigations in 

Florida: Florida Geological Survey Bulletin 11, 33 p.

———1936, Artesian water in the Florida peninsula: U.S. 

Geological Survey Water-Supply Paper 773-C.

Tibbals, C.H., 1990, Hydrology of the Floridan Aquifer 

System in east-central Florida: U.S. Geological Survey 

Professional Paper 1403-E, 98 p.

Toth, D.J., 1999, Water quality and isotope concentrations 

from selected springs in the St. Johns River Water 

Management District: St. Johns River Water Management District Technical Publication SJ99-2, 67 p.

U.S. Environmental Protection Agency, 2000, Current 

drinking water standards [cited 22 September 2000] 

http//:www.epa.gov/OGWDW/mcl.html.

White, W.A., 1970, The geomorphology of the Florida 

peninsula: Florida Department of Natural Resources, 

Bureau of Geology Geological Bulletin, No. 51, 164 p.
Appendix 35

APPENDIX
36 Ground-Water Quality of the Surficial Aquifer System and the Upper Floridan Aquifer, Ocala National Forest and Lake County,

FloridaAppendix. Site identification, well construction information, and water-quality data from the surficial aquifer system and the Upper Flo

[mg/L, milligrams per liter; oC, degree Celsius; μS/cm, microsiemens per centimeter at 25 oC; <, less than; --, unknown or not analyzed. Collecting agency: LC, Lake Water Management District; USGS, U.S. Geological Survey. Aquifer: F, Upper Floridan aquifer; S, surficial aquifer system. Map numbers shown in figures 5 and 6]

Site 

identification 

number

Map

 number Site name Collecting agency County Date of sample

Well 

depth 

(feet 

below 

land 

surface)

Casing 

length 

(feet)

Aq

WELLS

282225081413101 3 L-0623 SJRWMD Lake 04/15/93 437 262 282241081443901 4 Sand Mine deep L-0051 near Horsehead Pond SJRWMD Lake 08/02/93 115 85 282241081443902 5 L-0050 SJRWMD Lake 08/02/93 35 25 282245081492601 6 Eva 6” deep USGS Lake 02/05/97 192 18 282318081544003 7 L-0555 Green Swamp 4” deep (Hayes Grubb-LK751W/LK7425) USGS Lake 02/02/97 190 64 282502081422301 9 Lykes Bros. Replacement (S. Burger) 4” deep near Keene Lake USGS Lake 12/12/96 -- -- 282528081424801 10 L-0709 SJRWMD Lake 08/12/98 101 81 282528081424802 11 L-0710 SJRWMD Lake 08/13/98 -- -- 282533081430801 12 L-0677 SJRWMD Lake 08/14/98 485 160 282717081553101 13 ROMP 101 deep L-0056 near Bay Lake USGS Lake 02/12/97 404 118 282717081554401 14 USGS 2” shallow, SWFWMD site near Bay Lake USGS Lake 05/07/98 15 5 282729081443301 16 Lake Louisa State Park 4” deep L-0053 SJRWMD Lake 08/03/93 85 70 282823081500401 19 D. Patton 6” deep near Eva Firetower USGS Lake 12/12/96 390 96 283003081411401 20 L-0476 SJRWMD Lake 07/26/92 543 100 283019081455701 22 LCFD District 9 Station 1 4” deep near Crescent Lake, Clermont USGS Lake 05/30/97 -- -- 283024081410901 23 L-0459 SJRWMD Lake 07/07/92 213 85 283028081454701 24 Country Garden Nursery (S. Tyner) 4” deep, Clermont USGS Lake 09/08/99 -- -- 283114081503401 25 Bernard DuFrene 2” deep near Groveland USGS Lake 09/27/99 329 123 283114081503901 26 Johns Lake 4” deep L-0052 SJRWMD Lake 04/14/97 44 24 283128081404701 27 Johns Lake Well near Clermont USGS Lake 09/22/99 155 -- 283149081422801 28 L-0646 SJRWMD Lake 03/28/94 -- -- 283204081544901 29 Mascotte 6” deep L-0062 near Mascotte USGS Lake 02/12/97 160 66 283204081544902 30 Mascotte 6” shallow near Mascotte L-0041 SJRWMD Lake 05/06/93 30 16 283232081394101 31 Edgewater Beach 4” deep near East Johns Lake USGS Lake 01/23/97 -- -- 283349081445001 34 L-0596 SJRWMD Lake 05/04/93 918 605 283355081411701 35 Site 38 Turnpike, Waits Junction 4” deep L-0199 SJRWMD Lake 08/18/98 146 110 283355081411702 36 Site 38 Turnpike, Waits Junction 4” shallow L-0044 SJRWMD Lake 05/05/93 -- -- 283403081400002 37 L-0320 SJRWMD Lake 12/05/90 35 30 283432081530601 38 City of Mascotte 8” deep USGS Lake 02/14/97 291 143 283443081404002 39 L-0325 SJRWMD Lake 11/09/90 25 20 
Appendix 37

Appendix. Site identification, well construction information, and water-quality data from the surficial aquifer system and the Upper Flo[mg/L, milligrams per liter; oC, degree Celsius; μS/cm, microsiemens per centimeter at 25 oC; <, less than; --, unknown or not analyzed. Collecting agency: LC, Lake 

Water Management District; USGS, U.S. Geological Survey. Aquifer: F, Upper Floridan aquifer; S, surficial aquifer system. Map numbers shown in figures 5 and 6]

Site 

identification 

number

Map

 number

pH 

(standard units)

Alkalinity 

(mg/L as 

CaCO3)

Bicarbonate 

(mg/L 

as 

CaCO3)

Ammonia 

plus 

organic 

nitrogen 

(mg/L as N)

Nitrite 

plus 

nitrate 

(mg/L 

as N)

Phosphate 

(mg/L as 

P)

Calcium 

(mg/L)

Magnesium 

(mg/L)

Sodium 

(mg/L)

Potassium (mg/L)

Chloride 

(mg/L)

Su

(m

as 

WELLS

282225081413101 3 -- -- -- -- -- -- -- -- -- -- 13 282241081443901 4 8.0 -- -- .20 .02 -- 34 .89 3.2 2.3 7.0 282241081443902 5 5.0 -- -- .23 .02 -- 4.5 1.3 4.8 1.8 8.7 1282245081492601 6 7.6 143 174 <.20 <.02 .08 56 2.1 4.1 1.5 6.8 282318081544003 7 6.9 297 362 -- -- -- 110 4 11 .7 18 282502081422301 9 7.9 100 122 .47 <.02 .11 35 2.7 3 .6 4.6 282528081424801 10 7.4 452 551 -- -- -- 416 19 8.0 2.3 9.1 282528081424802 11 5.6 18 22 -- -- -- 4.1 2.2 11 .81 15 282533081430801 12 7.3 113 137 -- -- -- 48 7.3 5.5 1.6 12 3282717081553101 13 6.7 262 320 -- -- -- 100 3.2 6.4 .80 10 282717081554401 14 6.3 -- -- -- -- -- -- -- -- -- -- 282729081443301 16 8.2 -- -- .20 3.8 .02 23 12 4.5 .40 17. 282823081500401 19 7.9 106 129 <.20 .04 .07 42 1.0 3.6 .80 6.6 283003081411401 20 -- -- -- -- -- -- -- -- -- -- 3.0 283019081455701 22 7.2 107 131 -- -- -- 61 18 28 11 64 8283024081410901 23 -- -- -- -- -- -- -- -- -- -- 13 283028081454701 24 7.2 -- -- .22 6.1 .10 -- -- -- -- -- 283114081503401 25 6.9 -- -- <.20 .05 .03 -- -- -- -- -- 283114081503901 26 -- 35 43 -- -- -- 12 3.9 6.0 .50 14 283128081404701 27 7.1 -- -- .63 <.02 .01 -- -- -- -- -- 283149081422801 28 -- -- -- -- -- -- -- -- -- -- 11 2283204081544901 29 6.7 151 184 .79 .06 -- 59 1.2 5.4 .30 8.3 283204081544902 30 5.5 -- -- .30 .14 -- 3.4 .64 1.9 .25 2.9 283232081394101 31 6.4 81 99 .49 .40 .14 18 5.9 10 .8 23 283349081445001 34 8.0 -- -- .33 .02 -- 24 9.8 3.9 .48 6.3 283355081411701 35 8.1 59 72 <.20 5.8 .02 26 7.7 5.3 .63 11 283355081411702 36 6.5 -- -- .47 2.5 -- 21 6.4 3.2 6.4 4.3 3283403081400002 37 6.4 -- -- -- -- -- 27 14.8 6.0 9.7 -- 283432081530601 38 7.4 150 183 <.20 1.4 <.01 62 2.9 5.7 .6 11 283443081404002 39 6.4 -- -- -- -- -- 57 17.5 13 5.6 -- 
Florida

38 Ground-Water Quality of the Surficial Aquifer System and the Upper Floridan Aquifer, Ocala National Forest and Lake County, Appendix. Site identification, well construction information, and water-quality data from the surficial aquifer system and the Upper Flo

[mg/L, milligrams per liter; oC, degree Celsius; μS/cm, microsiemens per centimeter at 25 oC; <, less than; --, unknown or not analyzed. Collecting agency: LC, Lake 

Water Management District; USGS, U.S. Geological Survey. Aquifer: F, Upper Floridan aquifer; S, surficial aquifer system. Map numbers shown in figures 5 and 6] Site identification number Map num- ber Site name Collecting agency County Date of sample Well depth (feet below land surface) Casing length (feet) Aq

283530081514501 40 Dr. Phillips & Sons (Minute Maid Co.) 4” deep near Lake Lucy USGS Lake 12/12/96 141 73 

283535081545201 41 G. Barton 4” deep USGS Lake 11/19/98 -- -- 

283538081545401 42 L-0693 SJRWMD Lake 04/14/97 25 10 283540081402401 43 Montverde School 3” intermittent flow USGS Lake 11/22/96 180 -- 283549081401701 44 Montverde School 6” freeflow USGS Lake 08/24/99 120 -- 283621081405001 45 L-0674 SJRWMD Lake 04/16/96 -- -- 283652081412901 46 L-0675 SJRWMD Lake 04/16/96 -- -- 283655081412701 47 Freeflow 4” deep, Ferndale USGS Lake 01/29/97 123 -- 

283702081413801 48 L-0676 SJRWMD Lake 09/09/96 185 53 283720081421801 49 Ferndale Baptist Church 4” deep USGS Lake 01/29/97 90 -- 283744081415002 50 L-0308 SJRWMD Lake 12/05/90 15 10 283828081535701 53 Sunset Lakes Ski Center 4” deep, N of Mascotte USGS Lake 12/12/96 -- -- 283905081485401 54 Novelty Crystal Plant 4” deep USGS Lake 01/09/97 -- -- 283937081422101 56 Lake Apopka Restoration Area (SJRWMD) 4” freeflow USGS Lake 02/05/97 141 -- 284005081413901 57 L-0291 SJRWMD Lake 03/21/90 100 -- 284024081405301 59 L-0300 SJRWMD Lake 05/16/90 416 92 284024081405302 60 L-0301 SJRWMD Lake 12/05/90 22 20 284122081534401 63 Groveland Tower 4 deep L-0095 near Okahumpka SJRWMD Lake 05/05/93 364 148 284122081534402 64 Groveland Tower 4” shallow L-0096, SR 33 S of Okahumpka SJRWMD Lake 06/03/91 111 111 

284134081564201 65 Sunshine Peat (prev Hi Acres) 4” deep, 4 mi N of Center Hill USGS Lake 01/14/97 -- -- 284157081405401 67 L-0283 SJRWMD Lake 06/10/93 38 33 284209081424401 68 L-0285 SJRWMD Lake 06/27/90 14 4 284209081424402 69 L-0286 SJRWMD Lake 06/15/93 33 28 284253081441101 75 Astatula, J. Swaffer Park, 4” deep USGS Lake 03/05/97 -- -- 284320081410701 77 Apopka-Beauclair Canal 4” deep L-0139 at SJRWMD Office USGS Lake 01/23/97 650 575 

284322081410301 78 Apopka Lock, Field Station, 4” shallow L-0287 SJRWMD Lake 06/15/93 43 38 

284328081515901 79 Creek Farms 8” deep USGS Lake 02/05/97 539 145 284330081464201 81 Town of Howey In The Hills 14” deep #3 L-0591 SJRWMD Lake 05/04/93 350 162 284443081483201 84 L-0713 SJRWMD Lake 04/15/98 -- -- 284504081441501 85 Astatula 1 Landfill 4” shallow (8A) LC Lake 02/26/99 -- -- 
Appendix 39

Appendix. Site identification, well construction information, and water-quality data from the surficial aquifer system and the Upper Flo[mg/L, milligrams per liter; oC, degree Celsius; μS/cm, microsiemens per centimeter at 25 oC; <, less than; --, unknown or not analyzed. Collecting agency: LC, Lake 

Water Management District; USGS, U.S. Geological Survey. Aquifer: F, Upper Floridan aquifer; S, surficial aquifer system. Map numbers shown in figures 5 and 6]

Site 

identification 

number

Map

 number

pH 

(standard units)

Alkalinity 

(mg/L as 

CaCO3)

Bicarbonate 

(mg/L 

as 

CaCO3)

Ammonia 

plus 

organic 

nitrogen 

(mg/L as N)

Nitrite 

plus 

nitrate 

(mg/L 

as N)

Phosphate 

(mg/L as 

P)

Calcium 

(mg/L)

Magnesium 

(mg/L)

Sodium 

(mg/L)

Potassium (mg/L)

Chloride 

(mg/L)

Su

(m

as 

283530081514501 40 7.7 153 187 -- -- -- 58 3.3 7.9 .7 15 283535081545201 41 6.7 35 43 -- -- -- 20 4.7 11 5.4 29 2283538081545401 42 -- 14 17 -- -- -- 4 2.8 3.0 2.6 7.0 283540081402401 43 8.0 49 60 -- -- -- 15 4.4 2.9 .7 9.3 283549081401701 44 7.8 -- -- .22 .52 .01 -- -- -- -- -- 283621081405001 45 -- -- -- -- -- -- -- -- -- -- 8.0 283652081412901 46 -- -- -- -- -- -- -- -- -- -- 7.0 283655081412701 47 8.3 59 72 <.20 4.3 .02 21 5.8 4.4 .4 11 283702081413801 48 -- -- -- -- -- -- -- -- -- -- 6.0 283720081421801 49 7.9 78 95 <.20 7.5 .02 44 20 11 .6 28 5283744081415002 50 -- -- -- -- -- -- 3.0 1.4 2.0 6.3 -- 283828081535701 53 7.6 94 115 <.20 3.3 .08 41 1.7 5.0 .4 12 283905081485401 54 7.4 147 179 .22 <.02 .06 52 4.9 22 .8 22 283937081422101 56 8.1 68 83 <.20 4.3 .02 24 7.3 4.7 .4 14 284005081413901 57 -- -- -- -- -- -- -- -- -- -- 116 2284024081405301 59 -- -- -- -- -- -- -- -- -- -- 4.0 284024081405302 60 -- -- -- -- -- -- 91 21 11 7.1 -- 284122081534401 63 7.3 -- -- .49 .02 .05 68 2.4 5.7 1.7 10 284122081534402 64 7.9 100 122 -- 4.2 .14 54 2.4 6.0 1.0 13 284134081564201 65 8.6 143 174 -- -- -- 60 3.9 6.5 .5 12 1284157081405401 67 7.2 -- -- .84 .04 -- 31 9.8 5.0 1.0 7.1 284209081424401 68 -- -- -- -- .04 .06 16 1.9 8.2 4.7 8.8 284209081424402 69 7.6 -- -- 1.0 .10 -- 58 5.6 5.1 1.4 6.2 284253081441101 75 7.7 122 149 <.20 <.02 .03 34 8.6 5.0 .8 7.9 284320081410701 77 7.9 104 127 <.20 <.02 .01 31 7.6 5.0 .9 7.1 284322081410301 78 6.9 -- -- .21 .04 -- 47 5.4 48 .4 8.5 1284328081515901 79 7.6 106 129 .21 .88 .06 40 2.3 4.5 .6 8.4 284330081464201 81 7.5 -- -- .36 .95 -- 52 8.8 6.7 .8 12 284443081483201 84 -- -- -- -- -- -- -- -- -- -- 10 284504081441501 85 8.8 -- -- -- <.02 -- -- -- -- -- 6.8 
Florida

40 Ground-Water Quality of the Surficial Aquifer System and the Upper Floridan Aquifer, Ocala National Forest and Lake County, Appendix. Site identification, well construction information, and water-quality data from the surficial aquifer system and the Upper Flo

[mg/L, milligrams per liter; oC, degree Celsius; μS/cm, microsiemens per centimeter at 25 oC; <, less than; --, unknown or not analyzed. Collecting agency: LC, Lake 

Water Management District; USGS, U.S. Geological Survey. Aquifer: F, Upper Floridan aquifer; S, surficial aquifer system. Map numbers shown in figures 5 and 6] Site identification number Map num- ber Site name Collecting agency County Date of sample Well depth (feet below land surface) Casing length (feet) Aq

284528081530201 88 Church Of God of Prophecy 3” deep near Okahumpka USGS Lake 12/12/96 80 -- 

284725081361901 98 Wolf Sink (LCWA) 6” deep L-0600 near Sorrento USGS Lake 08/31/99 205 160 284732081495301 99 Frog Leg Ln 4” deep near Cisky Park, Leesburg USGS Lake 01/09/97 155 94 

284757081320701 101 L. Knowles 4” deep, 30845 CR435, Mt. Plymouth USGS Lake 01/14/97 154 126 284757081543002 102 C. R. Williams 4” deep, Caballo Rd., Leesburg USGS Lake 12/12/96 350 -- 284813081294001 106 L-0436 SJRWMD Lake 01/13/92 -- -- 284830081522401 107 City of Leesburg, PS #6 deep, Canal St. L-0592 SJRWMD Lake 11/02/93 390 58 284856081383001 110 City of Mt Dora 20” deep #3 USGS Lake 03/05/97 752 155 284922081494001 111 L-0452 SJRWMD Lake 09/11/96 180 41 284929081294901 112 Abandoned 10” freeflow off SR 46A near Sorrento USGS Lake 11/22/96 -- -- 284933081255801 113 L-0038 SJRWMD Lake 08/21/95 92 78 284936081475501 114 Lake-Sumter Community College QW 2” deep near Leesburg USGS Lake 01/24/97 -- -- 

285028081253301 119 Seminole State Forest 4” deep #1 L-0037 SJRWMD Lake 01/10/95 363 102 

285037081342002 120 L-0704 SJRWMD Lake 08/26/98 300 280 285037081342003 121 L-0714 SJRWMD Lake 11/15/98 -- -- 285057081243201 122 L-0032 SJRWMD Lake 10/19/94 120 96 285118081391001 123 City of Eustis Waterplant 16” deep L-0593, CR 44A SJRWMD Lake 11/03/93 750 274 

285144081475001 125 Leesburg Fire Tower 4” shallow L-0289 SJRWMD Lake 11/02/93 50 40 285144081475002 126 Leesburg Fire Tower deep L-0290 SJRWMD Lake 11/02/93 400 190 285152081542901 127 City of Fruitland Park, Cales Mem. Recreation Complex, deep USGS Lake 03/05/97 300 150 285230081242201 128 Lower Wekiva River State Preserve 2” freeflow #2, South USGS Lake 01/08/97 109 102 285233081284502 129 L-0716 SJRWMD Lake 11/29/98 37 22 285301081285401 130 Reese 4” deep near Cassia USGS Lake 01/27/97 -- -- 

285318081340601 131 Eustis Sand Co. 12” deep L-0375 USGS Lake 01/23/97 350 -- 

285419081552801 133 City of Lady Lake Water Tower deep L-0594 SJRWMD Lake 11/03/93 180 160 285425081323401 134 USGS 2” shallow L-0378, Lake Norris Rd. SJRWMD Lake 11/02/93 33 28 

285452081563201 135 R. P. Rowley 5” deep near Lady Lake USGS Lake 01/07/97 203 -- 285454081241201 136 Lower Wekiwa River State Preserve 2” int. flow #1, North USGS Lake 01/08/97 65 -- 285549081530601 137 Carlton Village Park Community 10” deep, Clearview Lake USGS Lake 02/20/97 350 203 285551081293601 138 B. Rogers 4” deep, Gourd Lake USGS Lake 01/15/97 -- -- 
Appendix 41

Appendix. Site identification, well construction information, and water-quality data from the surficial aquifer system and the Upper Flo[mg/L, milligrams per liter; oC, degree Celsius; μS/cm, microsiemens per centimeter at 25 oC; <, less than; --, unknown or not analyzed. Collecting agency: LC, Lake 

Water Management District; USGS, U.S. Geological Survey. Aquifer: F, Upper Floridan aquifer; S, surficial aquifer system. Map numbers shown in figures 5 and 6]

Site 

identification 

number

Map

 number

pH 

(standard units)

Alkalinity 

(mg/L as 

CaCO3)

Bicarbonate 

(mg/L 

as 

CaCO3)

Ammonia 

plus 

organic 

nitrogen 

(mg/L as N)

Nitrite 

plus 

nitrate 

(mg/L 

as N)

Phosphate 

(mg/L as 

P)

Calcium 

(mg/L)

Magnesium 

(mg/L)

Sodium 

(mg/L)

Potassium (mg/L)

Chloride 

(mg/L)

Su

(m

as 

284528081530201 88 7.9 112 137 -- -- -- 43 1.2 3.5 .3 5.6 284725081361901 98 7.8 -- -- .26 <.02 .12 -- -- -- -- -- 284732081495301 99 7.5 116 142 -- -- -- 34 7.6 3.9 .6 7.2 284757081320701 101 7.8 125 153 <.20 .36 .08 36 11 5.0 .6 8.9 284757081543002 102 8.0 133 162 -- -- -- 45 5.3 5.3 .9 11 284813081294001 106 -- -- -- -- -- -- -- -- -- -- 7.0 3284830081522401 107 7.7 -- -- .30 .05 -- 52 9.0 6.2 1.0 9.8 284856081383001 110 7.9 111 135 <.20 <.02 .06 32 9.6 7.3 1.1 12 1284922081494001 111 -- -- -- -- -- -- -- -- -- -- 8 1284929081294901 112 7.8 100 122 -- -- -- 41 2.3 5.1 .6 7.5 5284933081255801 113 7.7 169 206 -- -- -- 58 4.6 6.0 1.3 4.0 284936081475501 114 7.9 116 142 -- -- -- 35 8.8 4.6 .8 7.4 285028081253301 119 7.3 200 244 <.20 <.02 .03 161 40 232 8.2 448 28285037081342002 120 8.6 51 62 -- -- -- 21 4.3 4.5 .46 6.2 285037081342003 121 7.8 134 164 -- -- -- 33 15 39.3 1.5 5.7 4285057081243201 122 7.4 158 193 -- <.02 -- 146 58 430 12 695 25285118081391001 123 8.0 -- -- .23 .26 .04 29 8.8 6.2 2.5 11 1285144081475001 125 6.2 -- -- .22 .74 -- 5.4 1.3 2.1 .21 4.4 285144081475002 126 8.5 -- -- .20 .02 -- 33 6.5 4.8 2.5 7.2 285152081542901 127 7.7 108 132 -- -- -- -- -- -- -- 7.1 285230081242201 128 7.3 175 214 .31 <.02 .06 94 21 120 4.3 240 10285233081284502 129 6.8 19 23 -- -- -- 8.5 4.5 13 .74 24 285301081285401 130 7.5 143 174 <.20 <.02 .06 53 18 5.6 1 9 5285318081340601 131 7.7 123 150 <.20 <.02 .01 31 8.6 6.6 1 -- 285419081552801 133 8.1 -- -- .20 1.2 -- 31 5.1 3.6 .38 5.9 285425081323401 134 6.4 -- -- .25 .02 -- 10 4.9 4.3 3.7 6.5 3285452081563201 135 7.8 67 82 -- -- -- 17 9.2 2.5 .4 8.0 285454081241201 136 7.5 178 217 .46 <.02 .11 78 17 80 2.9 150 7285549081530601 137 7.9 102 124 -- -- -- 36 9.6 4.2 .8 8.0 2285551081293601 138 7.5 155 189 -- -- -- 44 12 4.8 .6 8.8 
Florida

42 Ground-Water Quality of the Surficial Aquifer System and the Upper Floridan Aquifer, Ocala National Forest and Lake County, Appendix. Site identification, well construction information, and water-quality data from the surficial aquifer system and the Upper Flo

[mg/L, milligrams per liter; oC, degree Celsius; μS/cm, microsiemens per centimeter at 25 oC; <, less than; --, unknown or not analyzed. Collecting agency: LC, Lake 

Water Management District; USGS, U.S. Geological Survey. Aquifer: F, Upper Floridan aquifer; S, surficial aquifer system. Map numbers shown in figures 5 and 6] Site identification number Map num- ber Site name Collecting agency County Date of sample Well depth (feet below land surface) Casing length (feet) Aq

285602081344301 139 K. Kruckenberg 4” int. flow, Will Murphy Rd. near Paisley USGS Lake 01/15/97 140 65 285606081353601 140 Coates Tree Farm 4” irrigation deep, 40324 CR 439 USGS Lake 01/06/97 180 84 285618081491101 141 G. Davis 4” deep, Emeralda Island USGS Lake 01/09/97 180 100 285628081400501 142 City of Umatilla PS Blanding deep L-0595 USGS Lake 03/05/97 450 137 285659081470901 143 USGS 4” shallow L-0699, near Lake Yale SJRWMD Lake 04/18/97 80 60 

285707081441101 144 J. F. Irvine Estate 4” deep L-0385 near Lake Yale USGS Lake 01/23/97 -- -- 

285810081234101 145 Lower Wekiva River St. Preserve 4” freeflow USGS Lake 11/19/98 87 83 

285908081470101 148 Big Bass Lake Recreation Area 4” deep M-0046 USGS Marion 02/19/97 198 -- 285930081430901 150 Ocala Forest Campground 6” deep, SR 42 near Altoona USGS Marion 01/16/97 134 -- 285933081324001 152 Paisley Fire Tower deep USGS Lake 01/15/97 -- -- 285934081262501 153 LCFD (District 2 Station 2) 4” deep, Lake Mack Rd. USGS Lake 01/15/97 -- -- 290002081483501 155 M-0254 SJRWMD Marion 08/19/91 81 71 290025081244801 156 Ocala NF 2” shallow near River Forest pumphouse, FSR 541 USGS Lake 12/17/98 20 10 

290026081244701 157 River Forest deep, FSR 541 near Forest Hills USGS Lake 02/28/97 52 48 290038081491901 158 M-0233 SJRWMD Marion 04/27/90 340 -- 290043081232801 159 River Forest 2” deep L-0059 near Crows Bluff SJRWMD Lake 04/18/95 170 153 290047081232501 160 River Forest 3” deep L-0400 near Crows Bluff USGS Lake 11/22/96 250 -- 290047081243401 161 L-0638 SJRWMD Lake 05/19/93 -- -- 290050081381201 162 Lake Dorr Recreation Area 4” deep USGS Lake 02/28/97 -- -- 

290155081332401 167 Bunch Ground Pond 4” shallow L-0702, Ocala NF USGS Lake 05/01/97 45 25 290208081250201 168 St. Francis 2” freeflow near Crows Bluff USGS Lake 01/06/97 -- -- 290220081485001 169 Doe Lake Camp 6” deep USGS Marion 02/27/97 166 -- 290228081382301 171 LCFD, District 4 - Station 6, 4” deep, SR 19 near Altoona USGS Lake 12/19/96 200 -- 290300081391801 173 FSR 573 USGS shallow USGS Marion 12/21/98 60 50 290300081420901 174 Ocala NF 2” shallow, FSR 573, 0.4 mi E of FSR 566 USGS Marion 12/18/98 70 60 

290300081452001 175 Big Scrub Camp 6” deep USGS Marion 02/27/97 147 -- 

290300081471701 176 Ocala NF 2” shallow, FSR 573, 0.8 mi W of FSR 523 USGS Marion 12/17/98 28 23 

290425081350801 179 Ocala NF 2” shallow near Alexander Springs, Paisley Rd. USGS Lake 12/07/98 23 18 

290436081383101 180 Railroad Grade Rd. 2” shallow, FSR 550 USGS Marion 05/19/97 40 30 290445081344001 181 Alexander Springs Recreation Area supply 4” deep USGS Lake 02/19/97 100 -- 
Appendix 43

Appendix. Site identification, well construction information, and water-quality data from the surficial aquifer system and the Upper Flo[mg/L, milligrams per liter; oC, degree Celsius; μS/cm, microsiemens per centimeter at 25 oC; <, less than; --, unknown or not analyzed. Collecting agency: LC, Lake 

Water Management District; USGS, U.S. Geological Survey. Aquifer: F, Upper Floridan aquifer; S, surficial aquifer system. Map numbers shown in figures 5 and 6]

Site 

identification 

number

Map

 number

pH 

(standard units)

Alkalinity 

(mg/L as 

CaCO3)

Bicarbonate 

(mg/L 

as 

CaCO3)

Ammonia 

plus 

organic 

nitrogen 

(mg/L as N)

Nitrite 

plus 

nitrate 

(mg/L 

as N)

Phosphate 

(mg/L as 

P)

Calcium 

(mg/L)

Magnesium 

(mg/L)

Sodium 

(mg/L)

Potassium (mg/L)

Chloride 

(mg/L)

Su

(m

as 

285602081344301 139 7.8 172 210 -- -- -- 49 11 7.5 1 10 285606081353601 140 7.4 175 214 -- -- -- 53 9.6 8.1 .8 8.0 285618081491101 141 7.5 138 168 -- -- -- 60 17 7.8 1.1 13 7285628081400501 142 8.0 100 122 .56 .02 -- 28 7.4 6.3 1.2 11 285659081470901 143 -- 22 27 -- -- -- 7.0 6.4 40 2.5 13 5285707081441101 144 7.4 104 127 -- -- -- 32 8.4 5.9 1.2 9.8 285810081234101 145 7.7 164 200 -- -- -- 54 7.1 4.2 .8 6.8 285908081470101 148 7.2 137 167 -- -- -- 37 9.7 4.6 .8 7.3 285930081430901 150 7.2 139 170 -- -- -- 40 10 12 .8 22 285933081324001 152 8.2 44 54 -- -- -- 12 4.5 4.9 .6 7.3 285934081262501 153 7.3 210 256 -- -- -- 83 2.8 5.0 .6 8.8 290002081483501 155 8.8 -- -- -- .34 .17 4.9 1.2 93 2.9 7.3 6290025081244801 156 4.4 3 4 .88 <.02 .22 1.5 .5 4.3 .2 7.4 290026081244701 157 7.2 187 228 -- -- -- 72 2.0 4.2 .5 7.6 290038081491901 158 -- -- -- -- -- -- -- -- -- -- 15 290043081232801 159 6.5 176 215 -- -- -- 69 21 101 4.2 189 3290047081232501 160 8.1 136 166 -- -- -- 28 23 99 3.7 180 1290047081243401 161 -- -- -- -- -- -- -- -- -- -- 67 1290050081381201 162 7.3 92 112 -- -- -- 28 8.7 5.0 .7 7.9 1290155081332401 167 5.2 13 16 -- -- -- 4.6 1.0 11 <.1 8.4 1290208081250201 168 7.5 168 205 -- -- -- 53 9.4 8.2 1.0 14 290220081485001 169 8.2 63 77 -- -- -- 16 4.2 4.2 1.6 5.5 290228081382301 171 7.6 76 93 -- -- -- 22 5.7 3.4 .6 5.4 290300081391801 173 6.7 47 57 <.20 .25 .02 5.4 .5 1.8 <.1 3.4 290300081420901 174 5.7 9 11 -- 1.6 .01 .8 2.5 1.5 .4 3.2 290300081452001 175 8.4 61 74 -- -- -- 17 6.9 2.8 .4 4.9 1290300081471701 176 6.2 59 72 .25 .10 .02 28 .05 .7 -- 1 1290425081350801 179 4.5 4 4 <.20 <.02 .01 .7 1.5 6.7 .2 13 290436081383101 180 5.1 6 7 -- -- -- .8 .6 4.4 <.1 6.4 290445081344001 181 7.6 83 101 -- -- -- 50 23 170 4.6 310 8
Florida

44 Ground-Water Quality of the Surficial Aquifer System and the Upper Floridan Aquifer, Ocala National Forest and Lake County, Appendix. Site identification, well construction information, and water-quality data from the surficial aquifer system and the Upper Flo

[mg/L, milligrams per liter; oC, degree Celsius; μS/cm, microsiemens per centimeter at 25 oC; <, less than; --, unknown or not analyzed. Collecting agency: LC, Lake 

Water Management District; USGS, U.S. Geological Survey. Aquifer: F, Upper Floridan aquifer; S, surficial aquifer system. Map numbers shown in figures 5 and 6] Site identification number Map num- ber Site name Collecting agency County Date of sample Well depth (feet below land surface) Casing length (feet) Aq

290451081344401 184 Alexander Springs 4” deep L-0066 SJRWMD Lake 07/18/95 102 74 290452081320001 185 Ocala NF 2” shallow, near Alexander Springs Wilderness USGS Lake 05/21/97 30 20 

290508081550301 187 M-0339 SJRWMD Marion 11/18/92 203 109 290512081542301 190 M-0331 SJRWMD Marion 09/08/92 200 -- 290526081493701 192 L. Schrimsher 4” deep, near Moss Bluff USGS Marion 01/07/97 -- -- 290531081423101 193 Ocala NF 4” shallow M-0412, S of US Naval Bombing Range USGS Marion 04/30/97 75 65 

290554081390501 197 Buck Lake Recreation Area handpump 4” deep USGS Marion 02/27/97 -- -- 

290613081402901 198 Farles Lake Recreation Area handpump 4” deep USGS Marion 02/27/97 -- -- 

290624081483901 200 M-0211 USGS Marion 12/11/98 69 57 290628081425301 201 Ocala NF Lookout Tower Bombing Range 4” deep USGS Marion 01/21/97 206 -- 

290633081375201 202 Camp Ocala 6” deep L-0407, Sellers Lake USGS Lake 02/26/97 -- -- 290646081314001 203 L-0441 SJRWMD Lake 02/03/97 113 104 290646081314002 204 L-0446 SJRWMD Lake 02/03/97 -- -- 290646081442801 205 Ocala NF 2” shallow, FSR 584 W of US Bombing Range USGS Marion 04/29/97 60 50 

290647081342101 206 Alexander Springs 4” deep L-0040 SJRWMD Lake 11/04/93 171 143 290647081342102 207 L-0456 SJRWMD Lake 03/01/94 32 22 290650081314001 208 Johnson deep, Levy Grant near Astor USGS Lake 11/22/96 -- -- 290703081553901 209 M-0343 SJRWMD Marion 06/14/94 -- -- 290805081540801 214 D. Craft 4” deep, Tomahawk Lake near Lynne USGS Marion 01/07/97 150 105 290820081305001 215 Alco Fish Camp (Frank Saul) 2” freeflow near Astor USGS Lake 11/22/96 146 135 290835081383001 217 Ocala NF 2” shallow, near US Naval Tracking Station USGS Marion 05/19/97 40 30 

290839081313401 220 L-0430 SJRWMD Lake 09/11/90 -- -- 290910081360001 222 Camp McQuarrie (4-H Club Foundation) 6” deep USGS Lake 06/17/98 152 135 

290913081313301 223 L-0333 SJRWMD Lake 09/11/90 -- -- 290940081313001 226 L-0434 SJRWMD Lake 09/11/90 -- -- 290947081313801 227 L-0429 SJRWMD Lake 09/12/90 -- -- 290950081315501 228 Astor (A.G. Edwards) 6” deep L-0045 SJRWMD Lake 08/14/91 254 204 291002081330601 230 Astor 6”deep L-0455 USGS Lake 12/01/98 150 100 291002081330603 231 L-0460 USGS Lake 12/07/98 30 20 291015081385001 234 DOT 49 6” deep M-0049, SR 19 and SR 40 USGS Marion 09/12/96 166 166 
Appendix 45

Appendix. Site identification, well construction information, and water-quality data from the surficial aquifer system and the Upper Flo[mg/L, milligrams per liter; oC, degree Celsius; μS/cm, microsiemens per centimeter at 25 oC; <, less than; --, unknown or not analyzed. Collecting agency: LC, Lake 

Water Management District; USGS, U.S. Geological Survey. Aquifer: F, Upper Floridan aquifer; S, surficial aquifer system. Map numbers shown in figures 5 and 6]

Site 

identification 

number

Map

 number

pH 

(standard units)

Alkalinity 

(mg/L as 

CaCO3)

Bicarbonate 

(mg/L 

as 

CaCO3)

Ammonia 

plus 

organic 

nitrogen 

(mg/L as N)

Nitrite 

plus 

nitrate 

(mg/L 

as N)

Phosphate 

(mg/L as 

P)

Calcium 

(mg/L)

Magnesium 

(mg/L)

Sodium 

(mg/L)

Potassium (mg/L)

Chloride 

(mg/L)

Su

(m

as 

290451081344401 184 7.7 83 101 -- .05 .03 56 22 166 2.9 359 7290452081320001 185 5.4 7 9 -- -- -- 2.2 1.2 3.4 1.0 6.7 290508081550301 187 -- -- -- -- -- -- -- -- -- -- 6.0 290512081542301 190 -- -- -- -- -- -- -- -- -- -- 4.0 2290526081493701 192 7.4 114 139 -- -- -- 39 4.6 3.8 1.0 6.4 290531081423101 193 6.1 13 16 -- -- -- 1.1 .3 10 .3 7.6 290554081390501 197 7.9 102 124 -- -- -- 30 5.6 4.2 1.1 5.0 290613081402901 198 8.0 90 110 -- -- -- 26 5.3 3.0 .6 5.5 290624081483901 200 6.2 -- -- -- -- -- -- -- -- -- -- 290628081425301 201 6.7 37 45 -- -- -- 11 3.6 3.4 .7 4.5 290633081375201 202 7.8 131 160 -- -- -- 36 9 5.0 .6 8.2 290646081314001 203 -- -- -- -- -- -- -- -- -- -- 7.0 290646081314002 204 -- -- -- -- -- -- -- -- -- -- 7.0 290646081442801 205 5.5 10 12 -- -- -- 1.3 .7 2.7 .2 3.3 290647081342101 206 7.4 -- -- .34 .10 -- 53 8.4 4.5 .43 7.7 290647081342102 207 5.6 -- -- .41 .02 -- 5.8 1.1 6.6 2.0 11 290650081314001 208 7.4 196 239 -- -- -- 57 13 3.9 .8 7.4 290703081553901 209 -- -- -- -- -- -- -- -- -- -- 5.0 290805081540801 214 7.7 107 131 -- -- -- 32 7.7 3.6 .6 6.1 290820081305001 215 7.9 9 11 -- -- -- 400 130 930 8.9 2,000 66290835081383001 217 5.1 5 7 -- -- -- .6 .5 8.0 <.1 11 290839081313401 220 -- -- -- -- -- -- -- -- -- -- 12 290910081360001 222 7.7 108 132 <.20 <.02 .08 37 2.8 8.2 .6 8.4 290913081313301 223 -- -- -- -- -- -- -- -- -- -- 764 18290940081313001 226 -- -- -- -- -- -- -- -- -- -- 216 4290947081313801 227 -- -- -- -- -- -- -- -- -- -- 1,110 18290950081315501 228 7.4 -- -- -- .02 .02 120 48 360 6.5 700 11291002081330601 230 6.9 208 254 .26 <.02 .04 70 6.5 5.1 .8 8.6 291002081330603 231 4.5 5 6 .29 <.02 .04 2.7 1.4 5.5 .2 12 291015081385001 234 7.7 80 98 .25 .05 -- 23 7.4 11 .7 21 
Florida

46 Ground-Water Quality of the Surficial Aquifer System and the Upper Floridan Aquifer, Ocala National Forest and Lake County, Appendix. Site identification, well construction information, and water-quality data from the surficial aquifer system and the Upper Flo

[mg/L, milligrams per liter; oC, degree Celsius; μS/cm, microsiemens per centimeter at 25 oC; <, less than; --, unknown or not analyzed. Collecting agency: LC, Lake 

Water Management District; USGS, U.S. Geological Survey. Aquifer: F, Upper Floridan aquifer; S, surficial aquifer system. Map numbers shown in figures 5 and 6] Site identification number Map num- ber Site name Collecting agency County Date of sample Well depth (feet below land surface) Casing length (feet) Aq

291034081322101 239 L-0627 SJRWMD Lake 02/05/93 -- -- 291051081495701 243 Mill Dam Lake Recreation Area supply 4” deep USGS Marion 02/21/97 -- -- 291100081502001 245 Mill Dam Lake 6” deep (SCE-123) USGS Marion 01/15/97 288 -- 

291115081592501 250 Sharpes Ferry Marion, Silver Springs 6” freeflow near Ocala USGS Marion 09/19/96 135 135 291117081540501 251 Redwater Lake 4” deep M-0044 USGS Marion 09/18/96 205 46 291117081540502 252 Redwater Lake 4” shallow M-0045 USGS Marion 09/18/96 10 2 291204081564801 261 Ocala NF 2” shallow, Cemetary Rd. near Ocala NF Boundary USGS Marion 05/19/97 35 25 

291230081594001 273 Silver Run 3” freeflow (SCE-154) near Silver Springs USGS Marion 09/24/98 -- -- 291235081593801 274 M-0271 SJRWMD Marion 05/10/91 -- -- 291440081384801 285 Ocala NF 2” shallow, SR19 entrance to Silver Glen Springs USGS Marion 05/06/97 60 50 

291448081381601 287 Juniper (Hunt) Club 4” deep near Silver Glen Springs USGS Lake 02/04/97 -- -- 291449081381701 288 Juniper (Hunt) Club 6” deep near Silver Glen Springs USGS Lake 01/14/97 -- -- 291513081515601 292 Lake Eaton handpump USGS Marion 02/20/97 96 -- 291600081550001 293 Fore Lake Recreation Area CE55 4” deep M-0036 USGS Marion 09/13/96 165 85 

291620081415001 294 Hopkin's Prairie Recreation Area handpump 4” deep USGS Marion 01/06/98 215 -- 291657081461501 295 Ocala NF 4” shallow (M-0408), FSR 88B & FSR 88 USGS Marion 01/09/98 55 35 

291728081390501 298 Ponderosa Club 2” freeflow M-0317 near Lisk Point, Lake George USGS Marion 09/12/96 -- -- 

291733081390301 299 M-0136 SJRWMD Marion 06/26/92 134 106 291739081390501 301 M-0326 SJRWMD Marion 06/27/92 -- -- 291750081392801 305 M-0253 SJRWMD Marion 06/28/92 -- -- 291750081494001 306 CE-56 6” deep, CR 314 near Salt Springs USGS Marion 01/14/97 184 -- 291751081414301 307 Ocala NF 4” shallow M-0413 USGS Marion 01/09/98 75 60 

291849081411401 309 Lake George 4” deep M-0021 near Salt Springs USGS Marion 09/11/96 298 268 

292053081393401 311 M-0220 SJRWMD Marion 01/29/90 143 124 292056081433901 312 M-0267 SJRWMD Marion 04/02/91 43 -- 292058081435101 313 M-0226 SJRWMD Marion 06/26/92 -- -- 292131081440601 316 M-0222 SJRWMD Marion 01/29/90 126 62 292200081510001 319 CE84 6” deep M-0024 near Salt Springs USGS Marion 09/04/96 90 53 

292240081483101 325 Grassy Pond Recreation Area handpump 4” deep M-0153 USGS Marion 02/21/97 201 -- 292403081422901 354 Ocala NF 2” shallow, FSR 47 & FSR 43 USGS Putnam 05/16/97 70 60 
Appendix 47

Appendix. Site identification, well construction information, and water-quality data from the surficial aquifer system and the Upper Flo[mg/L, milligrams per liter; oC, degree Celsius; μS/cm, microsiemens per centimeter at 25 oC; <, less than; --, unknown or not analyzed. Collecting agency: LC, Lake 

Water Management District; USGS, U.S. Geological Survey. Aquifer: F, Upper Floridan aquifer; S, surficial aquifer system. Map numbers shown in figures 5 and 6]

Site 

identification 

number

Map

 number

pH 

(standard units)

Alkalinity 

(mg/L as 

CaCO3)

Bicarbonate 

(mg/L 

as 

CaCO3)

Ammonia 

plus 

organic 

nitrogen 

(mg/L as N)

Nitrite 

plus 

nitrate 

(mg/L 

as N)

Phosphate 

(mg/L as 

P)

Calcium 

(mg/L)

Magnesium 

(mg/L)

Sodium 

(mg/L)

Potassium (mg/L)

Chloride 

(mg/L)

Su

(m

as 

291034081322101 239 -- -- -- -- -- -- -- -- -- -- 1,760 29291051081495701 243 7.9 96 117 -- -- -- 25 7.7 4.2 .6 7 291100081502001 245 7.2 142 173 -- -- -- 38 11 4.2 .5 7.4 291115081592501 250 7.7 160 195 -- .13 .05 48 12 7.1 1 7.7 1291117081540501 251 6.9 196 239 .47 .02 -- 56 14 5.6 1 7.1 291117081540502 252 5.1 3 4 -- -- -- .7 .5 2.1 1.3 3.2 291204081564801 261 5.2 8 9 -- -- -- .8 .5 3.2 <.1 3.8 291230081594001 273 7.4 134 163 <.20 <.02 .02 93 19 9.1 1.3 12 17291235081593801 274 -- -- -- -- -- -- -- -- -- -- 14 20291440081384801 285 5.9 14 17 -- -- -- 3.2 1.4 8.2 .6 12 291448081381601 287 7.5 60 73 -- -- -- 47 20 100 3 200 9291449081381701 288 7.0 91 111 -- -- -- 470 320 3,100 65 6,000 1,0291513081515601 292 7.6 147 179 -- -- -- 42 14 4.8 .9 7.2 1291600081550001 293 7.6 186 227 .33 .02 -- 48 16 7.1 2.2 12 291620081415001 294 7.3 172 210 .88 <.02 .13 55 7.6 5.9 .5 10 291657081461501 295 5.8 3 4 <.20 <.02 .04 .4 .4 3.5 .2 5 291728081390501 298 7.8 65 79 -- -- -- 48 20 95 3.6 170 11291733081390301 299 -- -- -- -- -- -- -- -- -- -- 198 10291739081390501 301 -- -- -- -- -- -- -- -- -- -- 259 6291750081392801 305 -- -- -- -- -- -- -- -- -- -- 150 8291750081494001 306 7.6 35 43 -- -- -- 16 5.3 4.4 .3 7.8 2291751081414301 307 6.2 8 10 <.20 .05 .83 .3 .1 9.1 .5 4.6 291849081411401 309 8.3 65 79 .20 .10 -- 44 18 97 3.4 180 8292053081393401 311 -- -- -- -- -- -- -- -- -- -- 257 18292056081433901 312 -- -- -- -- -- -- -- -- -- -- 176 13292058081435101 313 -- -- -- -- -- -- -- -- -- -- 183 11292131081440601 316 -- -- -- -- -- -- -- -- -- -- 99 1292200081510001 319 7.3 37 45 .20 .13 -- 14 2.8 3.4 .2 6.3 1292240081483101 325 8.4 41 50 -- -- -- 28 14 57 2.2 120 5292403081422901 354 5.7 9 11 -- -- -- 1.2 .9 3.1 .2 4.6 
Florida

48 Ground-Water Quality of the Surficial Aquifer System and the Upper Floridan Aquifer, Ocala National Forest and Lake County, Appendix. Site identification, well construction information, and water-quality data from the surficial aquifer system and the Upper Flo

[mg/L, milligrams per liter; oC, degree Celsius; μS/cm, microsiemens per centimeter at 25 oC; <, less than; --, unknown or not analyzed. Collecting agency: LC, Lake 

Water Management District; USGS, U.S. Geological Survey. Aquifer: F, Upper Floridan aquifer; S, surficial aquifer system. Map numbers shown in figures 5 and 6] Site identification number Map num- ber Site name Collecting agency County Date of sample Well depth (feet below land surface) Casing length (feet) Aq

292447081441401 364 SR 19 near Frontier 4” deep (P-0427) SJRWMD Putnam 02/28/94 148 95 

292447081441403 365 P-0820 SJRWMD Putnam 11/08/94 60 40 292543081483201 380 Ocala NF 2” shallow, FSR 75 & FSR 88 USGS Marion 01/07/98 51 41 

292548081471201 382 Lake Delancy Recreation Area handpump 4” deep USGS Marion 02/25/97 165 96 292817081483601 401 Ocala NF 2” shallow, FSR 88 & FSR 31 USGS Marion 12/12/97 60 50 

292817081483602 402 USGS 6” deep M-0410, FSR 88/31 USGS Marion 11/30/98 200 152 

292824081443301 405 Johnson's Field 4” deep P-0472 near Welaka USGS Putnam 12/08/98 144 -- 292824081443302 406 Johnson's Field 4” shallow P-0473 near Welaka USGS Putnam 12/08/98 45 -- 292948081503001 431 USGS deep P-0450, Rd. 77 & 77-G SJRWMD Putnam 03/06/95 241 215 292948081503002 432 USGS shallow P-0738, Rd. 77 & 77-G SJRWMD Putnam 03/06/95 102 92 

SPRINGS

02236095 1 Alexander Springs SJRWMD Lake 07/18/95 -- -- 283400081405100 2 Apopka (Gourd Neck) Spring near Oakland USGS Lake 05/28/96 -- -- 02243550 5 Blue Springs USGS Marion 05/18/99 -- -- 284455081494100 6 Blue Springs, Park Dr. near Yalaha USGS Lake 06/10/97 -- -- 285102081263900 7 Blueberry Spring, Seminole State Forest USGS Lake 06/11/97 -- -- 02237322 8 Bugg Spring USGS Lake 06/19/97 -- -- 285702081322400 9 Camp La-No-Che Springs vent 1 near Paisley USGS Lake 01/15/97 -- -- 285702081322401 10 Camp La-No-Che Springs vent 2 near Paisley USGS Lake 01/15/97 -- -- 292618081412100 12 Croaker Hole Spring near Welaka USGS Putnam 11/12/98 -- -- 284940081303800 13 Droty Springs near Sorrento USGS Lake 06/17/97 -- -- 02236132 14 Fern Hammock Spring USGS Marion 05/18/98 -- -- 284424081490500 16 Holiday Springs at Yalaha USGS Lake 06/10/97 -- -- 0223610 18 Juniper Springs USGS Marion 02/19/97 -- -- 284740081251701 19 Wekiva Falls Resort, Mastodon Springs USGS Lake 06/10/99 -- -- 02235255 20 Messant Spring USGS Lake 05/24/95 -- -- 285105081263800 22 Moccasin Springs, Seminole State Forest USGS Lake 06/11/97 -- -- 284452081495400 23 Mooring Cove Springs near Yalaha USGS Lake 06/17/97 -- -- 290220081260400 24 Mosquito Springs, Alexander Springs Wilderness USGS Lake 06/16/97 -- -- 285038081270100 27 Palm Springs, Seminole State Forest SJRWMD Lake 06/11/97 -- -- 02236205 31 Salt Springs USGS Marion 01/06/98 -- -- 
Appendix 49

Appendix. Site identification, well construction information, and water-quality data from the surficial aquifer system and the Upper Flo[mg/L, milligrams per liter; oC, degree Celsius; μS/cm, microsiemens per centimeter at 25 oC; <, less than; --, unknown or not analyzed. Collecting agency: LC, Lake 

Water Management District; USGS, U.S. Geological Survey. Aquifer: F, Upper Floridan aquifer; S, surficial aquifer system. Map numbers shown in figures 5 and 6]

Site 

identification 

number

Map

 number

pH 

(standard units)

Alkalinity 

(mg/L as 

CaCO3)

Bicarbonate 

(mg/L 

as 

CaCO3)

Ammonia 

plus 

organic 

nitrogen 

(mg/L as N)

Nitrite 

plus 

nitrate 

(mg/L 

as N)

Phosphate 

(mg/L as 

P)

Calcium 

(mg/L)

Magnesium 

(mg/L)

Sodium 

(mg/L)

Potassium (mg/L)

Chloride 

(mg/L)

Su

(m

as 

292447081441401 364 8.2 -- -- .20 .02 -- 23 .97 3.5 .68 4.6 292447081441403 365 6.0 -- -- .23 .12 -- 4 .8 19 .3 12 1292543081483201 380 6.6 15 18 .25 .58 .02 4.6 1.2 2.3 .2 3.1 292548081471201 382 8.2 42 51 -- -- -- 36 15 94 1.9 190 7292817081483601 401 6.6 37 45 <.20 .15 .40 7.9 4.1 2.7 .3 4.7 292817081483602 402 8.4 42 51 <.20 .20 .03 20 5.6 34 1 64 2292824081443301 405 7.8 79 96 <.20 .07 .02 98 43 360 5 720 16292824081443302 406 5.9 70 85 .24 <.02 .96 28 2.3 12 .4 20 292948081503001 431 9.0 -- -- -- .03 .01 29 14 88 1 177 3292948081503002 432 8.0 -- -- -- .15 -- 18 3 93 5.3 42 4

SPRINGS

02236095 1 7.8 80 98 -- .07 .05 46 23 144 3.5 307 6283400081405100 2 8.2 74 90 <.20 4.9 .03 29 7.5 5.2 .9 12 02243550 5 7.5 77 94 <.20 <.02 .02 42 17 130 3.6 240 5284455081494100 6 7.9 100 122 <.20 5.0 .04 39 5.8 4.3 .7 12 1285102081263900 7 7.5 -- -- -- -- -- -- -- -- -- -- 02237322 8 7.9 129 157 .24 .46 .09 48 3 5.2 .8 8.3 285702081322400 9 7.7 120 146 -- -- -- 58 14 6.6 .9 10 7285702081322401 10 7.7 121 148 -- -- -- 59 15 6.5 1 10 7292618081412100 12 7.9 65 79 -- .12 .024 74 39 340 8.5 670 15284940081303800 13 7.5 117 143 <.20 <.02 .08 41 11 5.0 .8 7.1 302236132 14 7.1 -- -- -- -- -- -- -- -- -- -- 284424081490500 16 7.7 105 128 <.20 4.1 .04 40 6.2 5.9 .7 14 0223610 18 7.8 45 55 -- .08 .03 13 4.4 2.4 .2 4.3 284740081251701 19 7.4 109 133 -- -- -- 110 38 210 5.4 400 2302235255 20 7.8 104 127 -- -- .03 100 22 7.1 1 10 24285105081263800 22 7.4 111 135 -- -- -- 140 51 340 10 620 38284452081495400 23 7.4 130 159 -- -- -- 48 6.9 9.6 1.2 15 1290220081260400 24 7.4 134 163 -- -- -- 47 4.3 5.4 .6 8.2 285038081270100 27 8.0 109 133 <.20 <.02 .04 130 40 180 6.5 320 3202236205 31 7.4 67 82 <.20 .10 .03 160 100 940 26 1,800 41
Florida

50 Ground-Water Quality of the Surficial Aquifer System and the Upper Floridan Aquifer, Ocala National Forest and Lake County, Appendix. Site identification, well construction information, and water-quality data from the surficial aquifer system and the Upper Flo

[mg/L, milligrams per liter; oC, degree Celsius; μS/cm, microsiemens per centimeter at 25 oC; <, less than; --, unknown or not analyzed. Collecting agency: LC, Lake 

Water Management District; USGS, U.S. Geological Survey. Aquifer: F, Upper Floridan aquifer; S, surficial aquifer system. Map numbers shown in figures 5 and 6] Site identification number Map num- ber Site name Collecting agency County Date of sample Well depth (feet below land surface) Casing length (feet) Aq

02235250 33 Seminole Springs USGS Lake 05/24/95 -- -- 285224081262400 34 Shark’s Tooth Spring, Seminole State Forest USGS Lake 06/12/97 -- -- 

02236160 35 Silver Glen Springs USGS Lake 02/04/97 -- -- 

284437081491700 39 Sun Eden Spring near Yalaha USGS Lake 06/17/97 -- -- 291307081393600 40 Sweetwater Springs along Juniper Creek USGS Marion 06/06/97 -- -- 292542081552600 41 Tobacco Patch Landing Spring Group 1, Ocklawaha River USGS Marion 03/03/99 -- -- 292521081551200 44 Wells Landings Springs, Ocklawaha River USGS Marion 03/03/99 -- -- 
Appendix 51

Appendix. Site identification, well construction information, and water-quality data from the surficial aquifer system and the Upper Flo[mg/L, milligrams per liter; oC, degree Celsius; μS/cm, microsiemens per centimeter at 25 oC; <, less than; --, unknown or not analyzed. Collecting agency: LC, Lake 

Water Management District; USGS, U.S. Geological Survey. Aquifer: F, Upper Floridan aquifer; S, surficial aquifer system. Map numbers shown in figures 5 and 6]

Site 

identification 

number

Map

 number

pH 

(standard units)

Alkalinity 

(mg/L as 

CaCO3)

Bicarbonate 

(mg/L 

as 

CaCO3)

Ammonia 

plus 

organic 

nitrogen 

(mg/L as N)

Nitrite 

plus 

nitrate 

(mg/L 

as N)

Phosphate 

(mg/L as 

P)

Calcium 

(mg/L)

Magnesium 

(mg/L)

Sodium 

(mg/L)

Potassium (mg/L)

Chloride 

(mg/L)

Su

(m

as 

02235250 33 7.9 84 102 -- 1.4 .05 45 11 5.0 .8 8.6 6285224081262400 34 7.1 114 139 <.20 .04 .05 64 18 62 2.1 110 1002236160 35 7.6 68 83 -- .05 .03 74 37 250 8.2 470 18284437081491700 39 7.7 111 135 -- -- -- 35 7 4.0 .5 8.1 291307081393600 40 7.7 75 92 -- .04 .02 110 62 590 17 1,000 27292542081552600 41 6.1 66 81 <.20 .17 .01 77 30 280 7.8 540 16292521081551200 44 6.8 58 71 <.20 .12 .01 64 26 220 5.7 410 13