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 AlfredCitrus 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 BARRANCH

BELLEAIR

CYPRESS CREEK

MORRISBRIDGE

SOUTH CENTRAL

NW HILLSBOROUGH DISPERSED

EASTLAKE

VERNA

ELDRIDGEWILDE

NORTHPASCO

ODESSACOSME

SOUTH PASCO

LAKELAND

SECTION 21

PIN

E ISLA

ND

SO

UN

D

CHAR LO TTE

H

AR

BO

R

CALOOSAHATCHEERIVER

LAKEOKEECHOBEE

Shell

Creek

Prairie

Creek

Hors

e Cr

eek

Peac

e Ri

ver

Big

Slou

gh C

anal

Dee

r P

rair

ie

Creek

Myakka River

LAKEISTOKPOGA

Lake

Jackson

Lake

Placid

Lake June

in Winter

Braden River

Manatee

River

Little M

anatee River

S. Prong

Reedy

Lake

Lake

Livingston

Lake

Clinch

Crooked

LakeBuffum

Lake

Peace

Rive

r

Lake

Arbuckle

Lake

Wechyokapka

Lake

Rosalie

Tiger

Lake

LAKE KISSIMM

EE

Lake Marian

TAMPA

BAY

HILLSB

ORO

UG

H

BAY

OLD TAMPA

BAY

Alafia

RiverN. P

rong

Lake

Hancock

Lake

Garfield

Lake

Pierce

Lake

Jackson

Cypress

Lake

Lake

Gentry

Alligator

Lake

Lake

PrestonEast Lake

Tohopekaliga

Lake

Hart

Lake Tohopekaliga

Lake

Conway

Lake

Hamilton

Lake

Marion

Lake

Juliana

Lake

Mattie

Lake

ParkerLake

Thonoiosassa

Blackwater

Creek

Rive

r

Hillsborough

Withlacoo

c hee

River

Lake

Tarpon

An c l ote

River

Pithlachascoiee

River

Crews

Lake

Lake

Monroe

Lake

Jessup

Lake

Harney

LAKEAPOPKA

LAKEHARRIS

LakeDora

Lake

Griffin

LakeEustis

Lake

Dorr

Lake

Norris

LakeWeir

Lake

Panasoffkee

Wek

iva

River

Lake

Louisa

Lake

Minnehaha

TSALA

APOPKA

LAKE

Crystal River

Springs Group

LAKEGEORGE

Lake

Woodruff

Lake

Disston

Lake

Kerr

ST. JOHNS RIVER

Oklaw

aha

River

Orange

Lake

Lake

Stafford

CRESCENTLAKE

Lochloosa

Lake

Newmans

Lake

ST.

JOHNS RIVER

Wekiva

River

Riv

er

Wac

cas

assa

GU

LF

OF

M

EX

IC

O

ATLAN

TIC O

CEA

N

Lithia

Springs

Sulphur

Springs

Rainbow

Springs

Homosassa

Springs

WeekiWachee

Springs

WarmMineralSprings

Chassahowitzka

Springs

Crystal

Springs

Crystal River 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

40

30

5010

20

70

80

90

100

110

120

70

60

10

20 30

10

60

20

80

30

20

70

40

50

50

50

50

70

60

80

90

70

30

10

40

40

50

60

70

50

506070

50

60

70

80

90

4

3

5

3

1

64

5

8

5

8

7

9

6

5

6

1

54

23

2

2

2

87

9

8

2

33

44

0

8

2

45

54

5

3

7 8

98

8

9

6

699

67 66

31

78

9

1

20

14

29

19

45

48

25

29

22

15

23

21

53

205252

5245

5345

54 54

50254745

45

1645

1546

4411

12

43

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4243

454126

173945

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5436

38 19414847

32 52 1738 45

40 49 4616

541345

434315 46

4819 39 51

464112

2633

364753

47

5257

5838 494741

2819 65

43 21

39

12 48

1850 1255

493934674033

416640

7153

1716

2060

21554178

8277

59 79 455078

79394420

8161

347539 87

41 74 49

5063 35

508551

397366

8672

70519590 82 4954 99

45

67 32875965

3535 36

6770

74 4691

44 437840 37

56

466240

49

6142

5250

72

69

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834663

43

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51

4750

51

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4419

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524644

85

82

22

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63

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37

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11

11

3315

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3712 1814 26

412562

4160

5860 6827

54 75727173

8732

6874 68

70

9040

65454531 6337 8273

7941

6862

75

6151 6297

47

8723

29

24

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11

4922

15 4094

29 55 715446 88

4632

34

2921

2829

20 9999

2448

3818 2939

9991

94

16 2384

9125

2382

63 85

20

12 2110

985917

8017

21 55186812

17 451114

7739 78

6213

35233615 37 59

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2313

9311

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89117828

8783

864314

1317

76 77

20

49

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884515

20 7462

38 82

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7015

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15 3527

185550

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33 583621

65

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303423

49 4944

4771

50

50 5124

42 5034483929

35 362933

5034

2137 44

422450

2448

48

3629

46

52

46

100

115

104

110

117109

105

124125

126104

127127

128

118

123113

100

117

100

108

104

1008

6

7

9

31

30

72

54

58

35

40

52

1960

57

59

49

31

17

1211

2942

18

81°

81°

82°

82°

83°

83°

84°

84°

29°

29°

28°

28°

27°

27°

SCALE 1:500,000MILES

KILOMETERS

5 0 5 10 15 20

5 0 5 10 15 20

AT

LA

NT

IC O

CEA

N

G U L F OF M

EX

I CO

STUDY AREA

MAP AREA

ALABAMA GEORGIA

FLORIDA

U.S. DEPARTMENT OF THE INTERIORU.S. GEOLOGICAL SURVEY

Prepared in cooperation with theSOUTHWEST FLORIDA WATER MANAGEMENT DISTRICT

Scientific Investigations Map 3148Ortiz, A.G., 2011, Potentiometric surface of the Upper

Floridan aquifer, west-central Florida, September 2010

POTENTIOMETRIC SURFACE OF THE UPPER FLORIDAN AQUIFER,WEST-CENTRAL FLORIDA, SEPTEMBER 2010

By A.G. Ortiz

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 ServicesBox 25286Denver, Colorodo 80225-0286

Figure 1. Change in potentiometric surface of the Upper Floridan aquifer from September 2009 to September 2010 in west-central Florida. Positive values indicate an increase in water-level altitudes.Negative values indicate a decrease in water-level altitudes.

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 September 2010. 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 wet season, when groundwater levels usually are at an annual high and withdrawals for agricultural use typically are low. The cumulative average rainfall of 53.17 inches for west-central Florida (from October 2009 through September 2010) was 0.41 inches above the historical cumulative average of 52.76 inches (Southwest Florida Water Management District, 2010). 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 September 13-17, 2010. Supplemental water-level data were collected by other agencies and companies. 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 61 percent of the wells measured in September 2010 were higher than the September 2009 water levels (Ortiz, 2010a). Data from 402 wells indicate the September 2010 water levels ranged from about 9 feet below to about 6 feet above the September 2009 water levels (fig. 1). The largest water level increase occurred in north-central Pasco County. The largest water level declines occurred in south-central Pasco County and north-central Manatee County (fig. 1).

Water levels in about 83 percent of the wells measured in September 2010 were higher than the May 2010 water levels (Ortiz, 2010b). Data from 413 wells indicate the September 2010 water levels ranged from about 5 feet below to 23 feet above the May 2010 water levels. The largest water level decline was in northwest Pasco County and the largest rise in water levels was in east-central Manatee 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

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

Ortiz, A. G., 2010a, Potentiometric surface of the Upper Floridan aquifer, west-central Florida, September 2009: U.S. Geological Survey Scientific Investigations Map 3117, 1 sheet.

Ortiz, A. G., 2010b, Potentiometric surface of the Upper Floridan aquifer, west-central Florida, May 2010: U.S. Geological Survey Scientific Investigations Map 3139, 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, 2010, Hydrologic conditions for the month of September 2010: Broooksville, FL, 84 p.

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.

VERNA

20

16

21

>= 5.00

0 to 4.99

<0 to -4.99

-5.00 to -9.99

EXPLANATION

Change in the potentiometric surface, in feet

(Positive values indicate an increase in water-level altitudes)