4

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4

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"

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"

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"

H

H

H

H

H

Ona

Tampa

Ocala

Venus

DeLand

Venice

Bartow

Ruskin

Brandon

Parrish

Palatka

Tavares

Orlando

Seville

Placida

Dunedin

Bronson

Gardner

Arcadia

Sebring

Sarasota

Lorraine

Bushnell

Oklawaha

Leesburg

Lakeland

Mulberry

Pineland

Suwannee

Palmdale

La Belle

Basinger

Wauchula

Englewood

Bradenton

Chiefland

Inverness

Homosassa

Kissimmee

Polk City

Davenport

Dade City

Avon Park

Fort Myers

Clearwater

Cross City

Fort McCoy

Rock Ridge

Plant City

Fort Ogden

Frostproof

Lake Wales

Fort Meade

Cape 

Coral

Punta Gorda

Myakka 

Head

Myakka City

Saint Cloud

Lake Alfred

Citrus Park

Zephyrhills

San Antonio

Brooksville

Port Richey

Gainesville

Lake Placid

Winter Haven

Daytona Beach

Fort Lonesome

Crystal River

Tarpon Springs

Port Charlotte

St. Petersburg

Altamonte Springs

STARKEY

DUNEDIN

CROSS BAR

RANCH

BELLEAIR

CYPRESS CREEK

MORRIS

BRIDGE

SOUTH CENTRAL

NW HILLSBOROUGH 

DISPERSED

EAST

LAKE

VERNA

ELDRIDGE

WILDE

NORTH

PASCO

ODESSA

COSME

SOUTH PASCO

LAKELAND

SECTION 21

PINE ISLAND SOUND

CHAR LO TTE

HA

RB

OR

CALOOSAHATCHEE

RIVER

LAKE

OKEECHOBEE

Shell Creek

Prairie

Creek

Horse Creek

Peace River

Big Slough Canal

Deer Prairie

Creek

Myakka River

LAKE

ISTOKPOGA

Lake

Jackson

Lake

Placid

Lake June

in Winter

Braden River

Manatee

River

Little Manatee River

S. Prong

Reedy

Lake

Lake

Livingston

Lake

Clinch

Crooked

Lake

Buffum

Lake

Peace River

Lake

Arbuckle

Lake

Wechyokapka

Lake

Rosalie

Tiger

Lake

LAKE KISSIMMEE

Lake Marian

TAMPA

BAY

HILLSBOROUGH

BAY

OLD TAMPA

BAY

Alafia River

N. Prong

Lake

Hancock

Lake

Garfield

Lake

Pierce

Lake

Jackson

Cypress

Lake

Lake

Gentry

Alligator

Lake

Lake

Preston

East Lake

Tohopekaliga

Lake

Hart

Lake Tohopekaliga

Lake

Conway

Lake

Hamilton

Lake

Marion

Lake

Juliana

Lake

Mattie

Lake

Parker

Lake

Thonoiosassa

Blackwater

Creek

River

Hillsborough

Withlacoochee

River

Lake

Tarpon

An c l o te

River

Pithlachascoiee

River

Crews

Lake

Lake

Monroe

Lake

Jessup

Lake

Harney

LAKE

APOPKA

LAKE

HARRIS

Lake

Dora

Lake

Griffin

Lake

Eustis

Lake

Dorr

Lake

Norris

Lake

Weir

Lake

Panasoffkee

Wekiva

River

Lake

Louisa

Lake

Minnehaha

TSALA

APOPKA

LAKE

Crystal River

Springs Group

LAKE

GEORGE

Lake

Woodruff

Lake

Disston

Lake

Kerr

ST. JOHNS RIVER

Oklawaha River

Orange

Lake

Lake

Stafford

CRESCENT

LAKE

Lochloosa

Lake

Newmans

Lake

ST.

JOHNS RIVER

Wekiva

River

River

Waccasassa

G U L F

O F

M

E

X

I

C

O

ATLANTIC OCEAN

Lithia

Springs

Sulphur

Springs

Rainbow

Springs

Homosassa

Springs

WeekiWachee

Springs

Warm

Mineral

Springs

Chassahowitzka

Springs

Crystal

Springs

L E E

P O L K

L A K E

D I X I E

TAYLOR

H E N D R Y

G L A D E S

O R A N G E

C I T R U S

M A R I O N

P U T N A M

D E S O T O

O S C E O L A

V O L U S I A

F L A G L E R

A L A C H U A

S A R A S O T A

S E M I N O L E

S T J O H N S

C H A R L O T T E

H I G H L A N D S

G I L C H R I S T

O K E E C H O B E E

P A S C O

H A R D E E

S U M T E R

M A N A T E E

P I N E L L A S

H E R N A N D O

H I L L S B O R O U G H

L E V Y

3

9 0

3

3 2

2

6

9

4

4

6

6

9

5

2

4

5

5

5

7

2

3 3

2 2

1

2

2

7 6

8

2

2 3

4

1

2

8

3 3

5 3

5 4 7

7 7 6

5 7 8

6 5

8

5

5 8

3 0 8

9

9

5 4 8

8

4

8

9

8

5

4

3 7

6

9

5

8

52

52 19 51 18

49

43

52 44

49

48 43 48 24

43

14 18

43

14

47

42

10

41

47

42 37 42

21 40 15 36

43 29 42 34

52

34

36 16 27 45 38

69 31

50 35 15

43 37 46 45

13

51

10 42

40

39 10 42

46 16

37

47 45

38 23 31

45 32 48 25

44

49 53

53

34 47 46 40

35 24

16

62 37

39

15 42 43

49 39

64 39

31 62 39 53

14

39 53 48 19

57 74 80

74 57

81

36 40 17

80 62 32

82 70 36 84

38 85

70 40 39

52 32 98 74

41

78 49 72 87 34

57

64 62

48 89 93 75 40 52

95

37 67

92

81 31

61 51 62 32 32 32 99

38 64

71 41

88

76 40 39

37 34 51

41 43

42 57

36

45

40

57

51

46

68

65 44

40

53 53 44

40

75

41

77

43

41

58

38

41

67

43

43

44 43

45

44

42

42 43

43 44

46

45

52

43

36

41

45

44

50

72

64 66

64 71

58

47

24

19

29

21

11

22

10

30 12

12

36 11 14

24

33 59

39

55

27

53 56

64

23 49 67 65 67

83 54 28 64

52 70

54

33 89

66

42

41

25 60 31

70

76

35 59

48

57 16 44

22 14 42 40 43

15

11

38

90 20 50

48

37 84

35

29 29

25

17

24

21

16 87 18 43 93 90

34

15

88

36 87

84 13 17

76

78 23

20

77

53

16 69 16

86

14

60 14

15 39

12 48 10 88 12

28

94

90

95

11 24 55 56

60

38 17 10 18

10 16 35 90

78 55

74

54

70 74

16 71

10

52 53

20

10

15 78

13

49

36

10

42

29

10 47

74

-6 27 22

12

14 33

-5

32 13

38 40 36 37

30

35 63

40

41 17 45

31 41

42

12

18

16

41

24

44 21

88

24

60

66

28 32

61

49

82

80

93

69

51

43

11

101 107

113 106

102

121

123

100 122

123

124

124

113

115

107

109

0

8

6

6

8

1

2

50

41

51

48

39

47

-8

18

41

24

15

10

10 17

-2

-8

13

-10

-14 -12

-11

30

20

70

40

10

50

90

100

110

-10

120

40

0

10

10

20

30

60

50

50

50

40

40

60

50

30

10

10

40

50

60

50

60

80

80

70

60

50

70

20

10

70

40

50

60

80

90

20

70

80

90

10

30

81°

81°

82°

82°

83°

83°

84°

84°

29°

29°

28°

28°

27°

27°

SCALE 1:500,000

MILES

KILOMETERS

5 0 5 10 15 20

5 0 5 10 15 20

A

T

LA

NT IC OCEAN

G U L F O F M E X I C O

STUDY AREA

MAP AREA

ALABAMA GEORGIA

FLORIDA

U.S. DEPARTMENT OF THE INTERIOR

U.S. GEOLOGICAL SURVEY

Prepared in cooperation with the

SOUTHWEST FLORIDA WATER MANAGEMENT DISTRICT

Scientific Investigations Map 3057

A.G. Ortiz , 2008, Potentiometric surface of the upper

Floridan aquifer, west-central Florida, May 2008

POTENTIOMETRIC SURFACE OF THE UPPER FLORIDAN AQUIFER,

WEST-CENTRAL FLORIDA, MAY 2008

By A.G. Ortiz

 2008 

Base from Southwest Florida Water Management District digital data, 1992,

State Plane Florida East projection, NAD83

Copies of this map can be purchased from:

U.S. Geological Survey

Branch of Information Services

Box 25286

Denver, Colorodo 80225-0286

Figure 1. Change in potentiometric surface of the Upper Floridan aquifer from May 2007 to 

May 2008 in west-central Florida. Positive values indicate an increase in water-level altitudes.

Negative values indicate a decrease in water-level altitudes.

EXPLANATION

MUNICIPAL WELL FIELD

POTENTIOMETRIC CONTOUR -- Shows altitude at which water would have stood in tightly cased wells. Contour interval is 10 feet.

 National Geodetic Vertical Datum (NGVD) of 1929. Hachures indicate depressions. Dashed where approximately located.

BOUNDARY OF SOUTHWEST FLORIDA WATER MANAGEMENT DISTRICT

OBSERVATION WELL -- Number is altitude of water level in feet above or below NGVD of 1929.

SPRING

" CITY OR TOWN

OBSERVATION WELL -- Number is altitude of water level in feet above or below NGVD of 1929.

 Bold number indicates water levels corrected for salinity.

NOTE: The potentiometric contours are generalized to synoptically portray the head in a dynamic hydrologic system, taking due account of the

variations in hydrogeologic conditions, such as differing depths of wells, nonsimultaneous measurements of water levels, variable effects of

pumping, and changing climatic influence. The potentiometric contours may not conform exactly with the individual measurements of water level.

VERNA

4

20

16

28

EXPLANATION

Change in the potentiometric 

surface, in feet

(Positive values indicate an 

increase in water-level altitudes)

10 to 14.99

5 to 9.99

>0 to 4.99

0 to -4.99

-5 to -10.00

 HYDROLOGIC CONDITIONS IN WEST-CENTRAL FLORIDA

 The Floridan aquifer system consists of the Upper and Lower Floridan aquifers separated 

by the middle confining unit. The middle confining unit and the Lower Floridan aquifer in 

west-central Florida generally contain highly mineralized water. The water-bearing units 

containing fresh water are herein referred to as the Upper Floridan aquifer. The Upper 

Floridan aquifer is the principal source of water in the Southwest Florida Water Management 

District and is used for major public supply, domestic use, irrigation, and brackish water 

desalination in coastal communities (Southwest Florida Water Management District, 2000).

 

 This map report shows the potentiometric surface of the Upper Floridan aquifer measured 

in May 2008. The potentiometric surface is an imaginary surface connecting points of 

equal altitude to which water will rise in tightly-cased wells that tap a confined aquifer 

system (Lohman, 1979). This map represents water-level conditions near the end of the dry 

season, when ground-water levels usually are at an annual low and withdrawals for 

agricultural use typically are high. The cumulative average rainfall of 46.95 inches for 

west-central Florida (from June 2007 through May 2008) was 5.83 inches below the historical 

cumulative average of 52.78 inches (Southwest Florida Water Management District, 2008). 

Historical cumulative averages are calculated from regional rainfall summary reports 

(1915 to most recent complete calendar year) and are updated monthly by the Southwest 

Florida Water Management District.

 

 This report, prepared by the U.S. Geological Survey in cooperation with the Southwest 

Florida Water Management District, is part of a semi-annual series of Upper Floridan aquifer 

potentiometric-surface map reports for west-central Florida. Potentiometric-surface maps 

have been prepared for January 1964, May 1969, May 1971, May 1973, May 1974, and for each 

May and September since 1975. Water-level data are collected in May and September each year 

to show the approximate annual low and high water-level conditions, respectively. Most of 

the water-level data for this map were collected by the U.S. Geological Survey during the 

period May 19-23, 2008. Supplemental water-level data were collected by other agencies and 

companies. A corresponding potentiometric-surface map was prepared for areas east and north 

of the Southwest Florida Water Management District boundary by the U.S. Geological Survey 

office in Orlando, Florida (Kinnaman and Dixon, 2008). Most water-level measurements were 

made during a 5-day period; therefore, measurements do not represent a "snapshot" of 

conditions at a specific time, nor do they necessarily coincide with the seasonal low 

water-level condition.

 WATER-LEVEL CHANGES

 Water levels in about 78 percent of the wells measured in May 2008 were higher than the 

May 2007 water levels (Ortiz, 2007). Data from 396 wells indicate the May 2008 water levels 

ranged from about 7 feet below to about 14 feet above the May 2007 water levels (fig. 1). 

The largest water level rise occurred in east-central Hillsborough County. Water level 

declines occurred in north-central Hardee County, east-central Polk County, and southwest 

Sarasota County (fig. 1).

 Water levels in about 73 percent of the wells measured in May 2008 were lower than the 

September 2007 water levels (Ortiz, 2008). Data from 404 wells indicate the May 2008 water 

levels ranged from about 24 feet below to 9 feet above the September 2007 water levels. The 

largest water level decline was in central Hardee County and the largest rise in water levels 

was in north-central Pasco County.

 ACKNOWLEDGMENTS

 The author thanks Tampa Bay Water and CF Industries for their assistance with the collection of 

data used to prepare this report.

 

 SELECTED REFERENCES

Kinnaman, S. L. and Dixon, J. F., 2008, Potentiometric surface of the Upper Floridan aquifer in 

 the St. Johns River Water Management District and vicinity, Florida, May 2008: 

 U.S. Geological Survey Scientific Investigations Map 3056, 1 sheet.

Lohman, S. W., 1979, Ground-water hydraulics: U. S. Geological Survey Professional Paper 708, 72 p.

Ortiz, A. G., 2008, Potentiometric surface of the Upper Floridan aquifer, west-central Florida, 

 September 2007: U.S. Geological Survey Open-File Report 2008-1105, 1 sheet.

Ortiz, A. G., 2007, Potentiometric surface of the Upper Floridan aquifer, west-central Florida, 

 May 2007: U.S. Geological Survey Open-File Report 2007-1380, 1 sheet.

Southwest Florida Water Management District, 2000, Aquifer characteristics within the Southwest 

 Florida Water Management District: Broooksville, FL, 123 p.

Southwest Florida Water Management District, 2008, Hydrologic conditions for the month of May 

 2008: Broooksville, FL, 81 p.