HIGHLANDS

DIXIE

G I L C H R I S T

LEVY

ALACHUA

PUTNAM

S T . J O H N S

MARION

FLAGLER

VOLUSIA

LAKE

S E M I N O L E

ORANGE

CITRUS

HERNANDO

SUMTER

PASCO

PINELLAS

HILLSBOROUGH

OSCEOLA

POLK

HARDEE OKEECHOBEE

D E S O T O

MANATEE

SARASOTA

CHARLOTTE

LEE

GLADES

HENDRY

VERNA

SOUTH

CENTRAL

MORRIS BRIDGE

NW HILLSBOROUGH

DISPERSED

CLEARWATER

DUNEDIN

EAST LAKE

ELDRIDGE

WILDE

ODESSA

COSME

SECTION

21

STARKEY

CYPRESS CREEK

CROSS

BAR

Old Tampa

Bay

Hillsborough Bay

Tampa Bay

Lake

Panasoffkee

Alligator

Lake

Lake

Preston

Lake

Gentry

Cypress

Lake

Lake

Marion

Lake

Hamilton

Lake

Minnehaha

Lake

Louisa

Lake

Juliana

Lake

Mattie

Lake

Parker

Lake

Butler Lake

Conway

Lake

Hart

Lake

Thonotasassa

Lake

Hancock

Lake

Garfield

Buffunt

Lake

Crooked

Lake

Lake

Weohyakapka

Lake

Rosalie

Tiger

Lake

Lake

Arbuckle

Reedy

Lake Lake

Clinch

Lake

Livingston

Lake

Marian

Lake Jackson

Lake

Jackson

Lake

June-In-Winter

Lake

Placid

Cross City

Chiefland

Gainesville

Daytona

Beach

DeLand

Fort

McCoy

Bronson

Ocala

Altamonte

Springs

Orlando

Oklawaha

Leesburg Tavares

Crystal

River

Homosassa

Brooksville

Port Richey

Tarpon Springs

Dunedin

Clearwater

St. Petersburg

Tampa

Sarasota

Polk City

Winter

Haven

Wauchula

Arcadia

Venice

Englewood

Port Charlotte

Punta

Gorda

Cape Coral

Fort Myers

La Belle

Palmdale

Lake

Placid

Sebring

Kissimmee

Saint

Cloud

Ona

Venus

Ruskin

Bartow

Wimauma

Gardner

Brandon

Parrish

Lorraine

Mulberry

Lakeland

Bushnell

Riverview

Dade City

Bradenton

Avon Park

Inverness

Plant City

Fort Ogden

Frostproof

Fort Meade

Lake Wales

Rock

Ridge

Zephyrhills

San

Antonio

Citrus

Park

Myakka City

Myakka

Head

Pine Island

Lake Alfred

Fort Lonesome

20

10

50

40

50

70

50

30

50

40

40

30

20

10

50

70

50

70

80

60

60

80

70

60

70

80

50 40

30

20

10

90

100

110

120

120

110

100

90

80

70

60

50

100

40

80

10

20

30

0

-10

10

0

40

30

60

70

50

Homosassa

Springs

Chassahowitzka

Springs

Rainbow

Springs

Weeki Wachee

Springs

Crystal

Springs

Sulphur

Springs

Lithia

Springs

Warm

Mineral

Springs

Crystal River

Springs Group

Silver

Springs

Rock

Springs

Wekiva

Springs Starbuck

Springs

Orange

Lake

Lake

Disston

Lake

Monroe

Lake

Jessup

Lake Eustis

Lake

Griffin Lake

Dora

Lake

Harris

Lake

Woodruff

Lake

Harney

Lake

Weir

Tsala Apopka

Lake

Lake

George

Crescent

Lake

Lake

Kerr

Lochloosa

Lake

Newnans

Lake

Lake

Stafford

O

ah

klaw

a

River

St. n

J ho

s

River

St. Johns River

Lake

Apopka

East

Lake

Tohopekaliga

Lake Tohopekaliga

Lake

Kissimmee

Lake

Istokpoga

Waccasassa

River

St. Johns

River

Caloosahatchee River

Kissimmee River

P

i

ea

R

ce

ver

Suwannee

River

Manatee River

Myakk

e

a

Riv

r

8

1

3

2 2

7

7

4

5

3 5

4

4

3

8

2

1

4 3

1 2

1

2

2

8

6

6

2

1 2

3

4

1

1 4

8 2 3 4

2

6

6

7 4

7

5

7

5

4 4

2

0

6

9

7

7

6 5 4 7

8

8

8

6

4

9

0

2

4

4 7

8

54

24

50 57

55 25

52

49

55

49

53

49

51 27 48 51

47

46

17 18

46

16 51

43

10

10

42

42

43 49 44

22 39 17

41 44 37 45

33 35 54 35

40 18

42

51 27

31

70

17 45

41 50 49 47

15

13 55 43

12

42

43

21 10

48

49 18 37 54 46

42 11 25

32

47 36

53 28 46 52 57

58

48 47

62

40 29

64

41

12 39

47

19

48

54

50 28 40

66 40

33

41

39

60

16 39

20

80 52 54

65

78

58

33

83 39 42 22

82

36 63

87 74

88 37 89

73 43

32 80 98

83 51

91

36

71 79

60 89 81 64 32

50 88 92

79

55 43

97

40

88

96 82 31

52 71 32

33 33 37

87 43

75 51 35

43 58 42 37

98

46 36

41

57

51 47

70

67 39

40

45

80

41

81

42 60

39

42

69

45

42 43 43

45 43

42

44

39 48

49

42

35

44

40

44

-9

74

65 66

64

69

58

45

38

22

18

26

19

18

10

20

11

36

14

14

43

12 16 31

30

45 23

60

25

59

58

66

23

50 69

70

53 74

28 66

51 70

53

31

40

39

24

59 28 70 75 33 55

50

84

22

40 41

11 16 20 50 53 37 89

38 83

36

43

23 25

21

17 23

21

21

15

88

92

17

43 90 33

14

89

36

88 13

16 77 22

18 82

14 53

15 15 70

87 13

10

59 62 12

13 38

10

99

23 97

21 56 58 11 38

12

34 98 83 13 57

-4

56

56

-2 73 76

73

10

-7 55

15

10

86 11

10

49 34

66

33 42

-8

24 10 19

-2 27

33 38 37 38

32 65

47

41

15 28 42

14

15 17

15

39

20

43

20

24

88

28 32

48

81

76

67

41

38

100 109 115 107

100

122

125

124

124

126 126

116

118

112

103

-14

-14

-10

CHANGE IN THE

POTENTIOMETRIC SURFACE,

IN FEET

EXPLANATION

0 10 20 30 KILOMETERS

0 10 20 30 MILES

SOUTHWEST FLORIDA

WATER MANAGEMENT

DISTRICT BOUNDARY

(Positive values indicate an

increase in water-level altitudes)

Figure 1. Change in potentiometric surface of the Upper Floridan aquifer from May 2005 to May 2006 in

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

indicate a decrease in water-level altitudes.

5

-9.99 to -5

-14.99 to -10

-19.99 to -15

-24.99 to -20

-25

≥

0 to 4.99

-4.99 to <0

≤

G U L F

O F

M E X I C O

ATLANTIC OCEAN

ALABAMA

GEORGIA

FLORIDA

M A P A R E A

STUDY

AREA

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 2006. 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 50.23 inches for

west-central Florida (from June 2005 through May 2006) was 2.82 inches below the

historical cumulative average of 53.05 inches (Southwest Florida Water Management

District, 2006). 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. Potentiometricsurface 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 15-19, 2006. Supplemental water-level

data were collected by other agencies and companies. A corresponding potentiometricsurface map was prepared for areas east and north of the Southwest Florida Water

Management District boundary by the U.S. Geological Survey office in Altamonte

Springs, Florida (Kinnaman, 2006). 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 95 percent of the wells measured in May 2006 were lower than the

May 2005 water levels (Ortiz and Blanchard, 2006). May 2006 water levels in 403 wells

ranged from about 26 feet below to about 6 feet above May 2005 water levels (fig. 1).

Significant water level declines occurred in eastern Manatee County, southwestern Polk

County, southeastern Hillsborough County, and in all of Hardee County. The largest

water level declines occurred in southwestern Hardee County. The largest water level

rises occurred in south-central Pasco County, northeastern Levy County, northwestern

Marion County, and along the gulf coast from Pasco County to Citrus County (fig. 1).

Water levels in about 96 percent of the wells measured in May 2006 were lower than the

September 2005 water levels (Ortiz, 2006). May 2006 water levels in 397 wells ranged

from about 31 feet below to 3 feet above the September 2005 water levels. The largest

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

was in south-central Pasco County.

ACKNOWLEDGMENTS

SELECTED REFERENCES

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

collection of data used to prepare this report.

Kinnaman, S.L., 2006, Potentiometric surface of the Upper Floridan aquifer in the St.

Johns River Water Management District and vicinity, Florida, May 2006: U.S.

Geological Survey Open-File Report 2006-1394, 1 sheet.

Lohman, S. W., 1979, Ground-water hydraulics: U. S. Geological Survey Professional

Paper 708, 72 p.

Ortiz, A.G., 2006, Potentiometric surface of the Upper Floridan aquifer, west-central

Florida, September 2005: U.S. Geological Survey Open-File Report 2006-1128, 1

sheet.

Ortiz, A.G., and Blanchard, R.A., 2006, Potentiometric surface of the Upper Floridan

aquifer, west-central Florida, May 2005: U.S. Geological Survey Open-File Report

2006-1009, 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, 2006, Hydrologic conditions for the

month of May 2006: Broooksville, FL, 81 p.

Lake

Okeechobee

Gulf of Mexico

27°

28°

29°

84° 83° 81°

27°

28°

29°

84° 83°

82°

82° 81°

POTENTIOMETRIC SURFACE OF THE UPPER FLORIDAN AQUIFER,

WEST-CENTRAL FLORIDA, MAY 2006

By

A.G. Ortiz

A.G. O , 2007, Potentiometric surface of the upper Floridan aquifer, west-central Florida, MAY 2006

OPEN-FILE REPORT 2007 1032 −

rtiz

Prepared in cooperation with the

SOUTHWEST FLORIDA WATER MANAGEMENT DISTRICT

U.S. DEPARTMENT OF THE INTERIOR

U.S. GEOLOGICAL SURVEY

Base from U.S. Geological Survey digital data.

Albers Equal-Area Conic projection,

Standard Parallels 29°30 ́ and 45°30 ́, central meridian 83°00 ́.

Copies of this map can be purchased from:

U.S. Geological Survey

Branch of Information Services

Box 25286

Denver, Colorado 80225-0286

5 20 MILES 0

5 20 KILOMETERS 0

POTENTIOMETRIC CONTOUR Shows altitude at which water would have stood in tightly cased

wells. Contour interval is 10 feet. National Geodetic Vertical Datum of 1929 (NGVD 1929).

Hachures indicate depressions.

SOUTHWEST FLORIDA WATER MANAGEMENT DISTRICT BOUNDARY

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

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

Bold italic number indicates water level corrected for salinity.

MUNICIPAL WELL FIELD

SPRING

CITY OR TOWN

−

−

−

EXPLANATION

45

VERNA

Port Charlotte

15

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.

Atlantic

Ocean

20