Eva

Ovedo

Ocala

Tampa

Cocoa

Geneva

DeLand

Starke

Holder

Bartow

Stuart

Eustis

Orlando

Holopaw

Sanford

Bunnell

Palatka

Arcadia

Sebring

Jupiter

Tavares

Altoona

Bushnell

Hastings

Boulogne

Callahan

Nobleton

Lakeland

Wauchula

Palmdale

Leesburg

Clermont

Umatilla

Basinger

Kissimmee

Lake Mary

Macclenny

Lake City

Williston

Inverness

Dade City

Polk City

Avon ParkFort Drum

Melbourne

Lady Lake

Christmas

Fort McCoy

Yankeetown

Fort Meade

Vero Beach

Frostproof

Eau Gallie

Titusville

Okeechobee

Brooksville

Pine Castle

Kenansville

Saint Cloud

Winter Park

Orange City

Lake Butler

Gainesville

Orange Lake

Lake Placid

Fort Pierce

Cocoa Beach

Salt Springs

Winter Haven

Ormond Beach

Jacksonville

Daytona Beach

Flagler BeachCrescentCity

St. Augustine

Crescent Beach

Orange Springs

Yeehaw Junction

Merritt Island

West Palm Beach

New Smyrna Beach

FernandinaBeach

Keystone Heights

Lake Panasoffkee

Altamonte Springs

Green Cove Springs

JacksonvilleBeach

South Ponte Vedra Beach

Dunnellon

Lake Wales

POLK

LAKE

LEVYMARION

PALM BEACH

OSCEOLA

VOLUSIA

HENDRY

BREVARD

DUVAL

CLAY

ORANGE

PASCO

ALACHUA PUTNAM

GLADES

HIGHLANDS

CITRUS

BAKER

NASSAU

HARDEE

COLUMBIA

MARTINDESOTO

ST LUCIE

HILLSBOROUGH

ST. JOHNS

FLAGLER

OKEECHOBEE

INDIAN RIVER

UNION

GILCHRIST

SUMTER

HERNANDO SEMINOLE

BRADFORD

CHARLTON CAMDEN

WARE

Wolf Sink

Big Spring

Ruth Spring

Gum Springs

Bugg Spring

Blue Spring

Wekiva Falls Resort

Salt Springs

Rock Springs

Palm Springs

Blue Springs

Blue Springs

Potter SpringMiami Springs

Little Spring

Island Spring

Apopka Spring

Wekiwa Springs

Wekiva Springs

Silver Springs

Messant Spring Gemini SpringsFenney Springs

Rainbow Springs

Juniper Springs

Holiday Springs

Crystal Springs

Crescent Beach Spring (submarine)

Beecher Springs

Seminole SpringsHomosassa Springs

Alexander Springs

Sweetwater Springs

Green Cove Springs

Silver Glen Springs

Fern Hammock SpringsPonce De Leon Springs

Chassahowitzka Springs

Ichetucknee Springs Group

Crystal River Spring Group

Blue Springs

Orange Springs

Starbuck Spring

Big Blue Spring

Sanlando Springs

Croaker Hole Spring

Sante Fe River Spring Group

Ocklawaha River Spring Group

Panasoffkee River

Spring Group

Juniper Creek Tributary Seepage

Black Sink

Devil's Den Sink

St.

St. Johns River

Johns

River

BlueCypress

Lake

GULFOF

MEXICO

CypressLake

LakeTohopekaliga

East LakeTohopekaliga

LakeEustis

Lake Harris

LakeApopka

LakeMonroe

Lake

Harne

y

LakeGeorge

Lake

Griffi

n

Lake

Ocklawaha

River

WithlacoocheeRiver

ATLANTICOCEAN

Lake Kissimmee

Kissimmee River

Lake Okeechobee

Dora

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FLORIDA

GEORGIA

MAP AREA

SFWMD

SWFWMD

SJRWMD

SRWMD

N

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

Prepared in cooperation withST. JOHNS RIVER WATER MANAGEMENT DISTRICTSOUTH FLORIDA WATER MANAGEMENT DISTRICT

SOUTHWEST FLORIDA WATER MANAGEMENT DISTRICTOPEN FILE 2007-1371

Sandra L. Kinnaman and Joann F. Dixon, 2007, Potentiometric surface of the Upper Floridan aquifer in the St. Johns River Water Management District and vicinity, Florida, May 2007

Base from U.S. Geological Survey digital data, 1:100,000, 1983Universal Transverse Meracator projection, Zone 17

POTENTIOMETRIC SURFACE OF THE UPPER FLORIDAN AQUIFER IN THE ST. JOHNS RIVER WATER MANAGEMENT DISTRICT AND VICINITY, FLORIDA, MAY 2007

By Sandra L. Kinnaman and Joann F. Dixon

2007

Copies of this map can be purchased from:U.S. Geological SurveyBranch of Information ServicesBox 25286Denver Federal CenterDenver, Colorado 80225-0286

INTRODUCTIONThis map depicts the potentiometric surface of the Upper Floridan aquifer in the St. Johns River Water Management District and vicinity for May 2007. Potentiometric contours are based on water-level measurements collected at 566 wells during the period May 4 – June 11, near the end of the dry season, however most of the water level data for this map were collected by the U. S. Geological Survey during the period May 21-25, 2007. Some contours are inferred from previous potentiometric-surface maps with larger well networks. The potentiometric surface of the carbonate Upper Floridan aquifer responds mainly to rainfall, and more locally, to ground-water withdrawals and spring flow. Potentiometric-surface highs generally correspond to topographic highs where the aquifer is recharged. Springs and areas of diffuse upward leakage naturally discharge water from the aquifer and are most prevalent along the St. Johns River. Areas of discharge are reflected by depressions in the potentiometric surface. Ground-water withdrawals locally have lowered the potentiometric surface. Ground water in the Upper Floridan aquifer generally flows from potentiometric highs to potentiometric lows in a direction perpendicular to the contours.

SUMMARY OF HYDROLOGIC CONDITIONS

ADDITIONAL REFERENCELong-term hydrographs of ground-water levels for continuous and periodic wells are available at internet site: http://waterdata.usgs.gov/fl/nwis/gw

Measured values of the potentiometric surface ranged from 9 feet below NGVD29 near Fernandina Beach, Florida, to 124 feet above NGVD29 near Polk County, Florida. The average water level of the network in May 2007 was about 4 feet lower than the average in September 2006 following below-average rainfall during the dry season of 2006-07. Seasonal differences in network average water levels generally range from 4 to 6 feet. For 532 wells with previous measurements, May 2007 levels ranged from about 26 feet below to about 8 feet above September 2006 water levels. Water levels decreased 20 feet or more from September 2006 to May 2007 in 6 of the 48 wells measured in Polk County and the 2 wells measured in Hardee County. The average water level of the network in May 2007 was about 3 feet lower than the average in May 2006. For 535 wells with previous measurements, May 2007 levels ranged from about 21 feet below to about 5 feet above May 2005 water levels.

NOTE: The potentiometric contours are generalized on a regional scale to portray water levels in a dynamic hydrolgic system taking due account of the variations in hydrogeologic conditions such as well-depth differences,non-simultaneous measurements of water levels, variable effects of pumping, and changing climatic infulence. The potentiometric contours, thus, may not conform exactly with individual measurements of water level.

EXPLANATIONPOTENTIOMETRIC CONTOUR -- Shows altitude at which water level would have stood in tightly cased wells. Hatchures indicate depressions. Contour intervals 10 feet. Vertical datum is NGVD29. STATE WATER MANAGEMENT DISTRICT BOUNDARY SJRWMD -- St. Johns River Water Management District SRWMD -- Suwannee River Water Management District SFWMD -- South Florida Water Management District SWFWMD -- Southwest Florida Water Management DistrictSURVEYED WELL WITH KNOWN OPEN-HOLE INTERVAL -- Measuring-point datum is referenced to benchmark datum. Number is altitude of water level in feet above or below NGVD29SURVEYED WELL WITH UNKNOWN OPEN-HOLE INTERVAL -- Measuring-point datum is referenced to benchmark datum. Number is altitude of water level in feet above or below NGVD29UNSURVEYED WELL WITH KNOWN OPEN-HOLE INTERVAL -- Measuring-point datum is estimated from topographic map. Number is altitude of water level in feet above or below NGVD29UNSURVEYED WELL WITH UNKNOWN OPEN-HOLE INTERVAL -- Measuring-point datum is estimated from topographic map. Number is altitude of water level in feet above or below NGVD29

SINKHOLE -- Surface collapse feature exposing the Upper Floridan aquifer. Where measured, number is altitude of water level in feet above NGVD29

FLOWING BOREHOLESPRING -- Line indicates direction of spring outflow

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