UNITED STATES DEPARTMENT OF THE INTERIOR
GEOLOGICAL SURVEY


MAP SERIES NO. 65


FLORIDA DEPARTMENT OF NATURAL RESOURCES
published by BUREAU OF GEOLOGY


89 88a 87 86 85 84 83 82 81 80
1 1 1 1 1 1 1,1a


31" -


30o--


THE OBSERVATION-WELL
NETWORK OF THE U. S. GEOLOGICAL SURVEY
IN FLORIDA

by
Henry G. Healy

Prepared by
UNITED STATES GEOLOGICAL SURVEY
in cooperation with
FLORIDA DEPARTMENT OF NATURAL RESOURCES
BUREAU OF GEOLOGY
Tallahassee
1974

INTRODUCTION

An observation-well network has been established throughout
Florida to evaluate the status of ground-water resources in each aquifer.
The network provides basic documentation of the effects of natural
variations and the effect of man on the ground-water resource. The
network also provides the data by which the potential of the ground-
water resources can be determined. The observation-well network is
part of the statewide hydrologic monitoring network used to evaluate
the total water resources of the State. (This hydrologic network has
been described by Conover and others, 1965.)
The purpose of this water atlas is to acquaint the reader with the
overall operation and extent of the observation-well network in Florida,
the distribution of wells, and the frequencies and types of observation
as a means of demonstrating the systematic approach used by the U.S.
Geological Survey in cooperation with State, local, water-management
districts, and other Federal agencies in evaluating and appraising the
ground-water resources of the State.
Management of the network is dynamic: the network is constantly
being revised in response to the varying needs brought about by
water-resource problems and application of new hydrologic techniques.
The statewide network began in 1930 when the 1929 State Legislature
enacted a law, applicable to the Gulf-bordering Counties of Sarasota,
Manatee, and Charlotte regulating the drilling and operation of wells
and the conservation of ground water. To administer the new law
successfully, acquisition of more information relating to the availability
of ground water of that region, as well as other sections of the State
where ground-water problems existed, proved necessary. As a result, in
1930 the State Geologist of Florida arranged for a cooperative program
with the U.S. Geological Survey to make water-level measurements in
selected wells in Sarasota County and in the Jacksonville area where
ground-water data were badly needed.
From the modest beginning of the observation-well network in
Sarasota and Duval Counties, the water-level measurement program
was, by 1935, extended into Manatee, Orange, Duval, Pinellas,
Seminole, Hillsborough, and Charlotte Counties because of the urgent
need for information on the potential of the ground-water reservoirs, or
aquifers, in those counties. By 1939, the U.S. Geological Survey had set
up observation-well networks in southeast and northwest Florida and in
other areas in west-central Florida. The network was gradually
expanded as ground-water problems became more acute; by January
1974, the network consisted of 1,211 observation wells. In addition, a
large number of observation wells are measured to collect hydrologic
and water quality information as part of the water-resources project
investigations in Florida.
The purpose of the program is to systematically acquire hydrologic
data on representative wells in an area. Data from these wells are used
to determine the hydrologic characteristics of the aquifer, the cause and
effect relations of fluctuations that occur, and the trends of water levels
in the aquifer. The observation-well program must have as its basis
therefore the selection of those wells that are representative of the
many wells in any given area. Commonly, in an area in which there may
be as many as several tens of wells tapping a given aquifer, information
from ten wells or less, all carefully selected for measurement, will
supply most of the information needed to evaluate the aquifer's
response to hydrologic stress (Healy, 1964).
By analyzing the data from a limited number of observation wells in
an area, the ground-water regimen for that area can become known, and
the network then becomes an important part of the overall hydrologic
investigation of the area. For example, with other hydrologic
parameters, the network can be used to: (1) show the rate and direction
of ground water movement; (2) define the past, present, and future
trends of water levels in aquifers; (3) estimate or forecast the base flow
of streams and the relation between streamflow and ground-water
levels; (4) indicate where water levels are near land surface and water
logging may occur; (5) show where levels are declining toward optimum
limits of economic lift or impairment of water of good quality; (6)
provide data for evaluating the effectiveness of land-management and
water-conservation programs; (7) provide records to show the effects of
natural and man-induced forces that act on an aquifer; and (8) furnish
data for use in basic research.

FUNDING OF THE PROGRAM

The observation-well program in the State of Florida is supported in
part by local Florida governmental agencies and by various state and
federal agencies.
As of January 1974, the network was maintained and operated by
the U.S. Geological Survey in cooperation with the Florida Bureau of
Geology, the Central and Southern Florida Flood Control District, the
Southwest Florida Water Management District and other state and
Federal agencies, counties and municipalities (table 1).

DISTRIBUTION OF WELLS

The distribution of wells used in the ground-water monitoring
network as of January 1974 is shown on the map. A major factor
affecting the distribution of observation wells in a given area is the
extent to which ground-water pumping is heavy because of the
increasing demand by municipalities, industries, and agriculture.
Indirectly, demographic factors also control the distribution of
observation wells. For example, because much of the southern coastal
areas contain a large segment of the State's population, these areas
exhibit an attendant increased use of water. Also, industrial demand for
water tends to concentrate in specific areas where an abundant supply
of raw materials exist. An example of this is central Polk County where
phosphate mining is prevalent.
Observation wells are needed in areas where actual or potential
critical water problems have developed or may develop. The tendency
of both people and industry to cluster produces a decidedly
non-uniform distribution of water development. This situation is most
likely to cause such problems as water shortages or deterioration in
water quality such as salt-water intrusion. The more critical the
problem the more detailed must be the field data used to delineate and
interpret the problem. Thus, more observation wells are required to
provide these data in problem areas than in areas where comparatively
little water development has taken place. Major problem areas and
potential problem areas of major water use and development include
most of southeast coastal Florida from Palm Beach County to and
including most of Dade County; the Tampa-St. Petersburg area in
Pinellas, Hillsborough and Pasco Counties; DeSoto, Hardee, and Polk
Counties in south-central peninsular Florida; the Orlando area in
Orange County; Collier, Lee, Sarasota, and Manatee Counties; and the
Fernandina-Jacksonville area in Nassau and Duval Counties.
Observation wells in the network are concentrated in these problem
areas.


1964 Two-variable linear correlation analyses of water-level
fluctuations in artesian wells in Florida: Research, US.
GeoL Survey Prof. Paper 501-D, p. D199-D202.
Pride, R.W.
1973 Estimated water use in Florida: Florida Dept. Nat.
Resources, Bur. GeoL Inf. Circ. 82.







87


Shallow sand Aquifer and others






Figure 1. Ground-water use by counties and the major ground-water sources.


7 Sample and chemical analyses. May include
wells in preceding categories.

(Number refers to the number of observation wells
in use)


0 O 20 3 0 ei.


85 84*


I
I


d







05 to 20


FLOR IDA GEO IJ[.G IC SURVEY MAP SER IES3


Thirteen
percent of
wells in in
Columbia, l
County.
The num
listed in Ta
is the pri
agricultural
which under
Beach Cou
part of the
of Florida
sand-and-
Escambia, S



Water-leI
basis. The
use of the
delineate tr
the events
precipitation
pumping o
fluctuations
gradual cli
changes affi
Periodic
annual, an
periodic I
bimonthly,
1).
Annual
semiannual
measureme
measurement
of trends
superintend
several sepa
In addit
quality-of-g
Survey in
analyses fro
The type o
analysis wil
The che
establish aI
water in ea
movement
in quality;'
monitor shi
The che
calcium, so
fluoride, ni
strontium,
and pH. Un
boron, alum
organic com
Frequency
those of m
from annual
complete an
few consti
determined
measured a
that autom
simultaneous



All record
since the in
Measuremei
the Florida
Annual Rep
of Florida
Paper 773-
data-collect
published in
As of Jan
were availa
Bureau of G
serial numb
record. The
"Ground- W
sections of
Southeastern
an annual
of record i
years 1956
do not con
Florida Bur
Table 2. T
Nonartesian
published in
In addition
wells in Fl
these lists,
available fr
Knox Rd.,



Conover, C.
1965


Healy, H.G.


--__ -._ DEPARTMENT OF NATURAL RESOURCES
SANTA ROSA _-.___BUREAU OF GEOLOGY
SSANTA ROSA f |HOLMES /
S3 A C K 3 3 This public document was promulgated at a total
\ / -- ACKSON cost of $430.00 or a per copy cost of $.29 for the
A L T 2\ ON A_- -- A -- purpose of disseminating hydrologic data.
S- W A L T O N A S & A tJ


r i WASHINGTOMN 1 J S A --O- 6 -



,, ,SY-- i- 2 "/ -- .. .. AKERu
3. /S -W --N-
counties each with 20 or more observation wells have 64 / 1 U A CO 12
the total number of wells in the network. The number of LIBERTY \ TAYLOR 2 COLUMIA
dividual counties range from one well each in Bradford, --- I1
Gulf, Hamilton, and Manatee Counties to 267 wells in Dade L UNO /2

nbers of wells tapping the principal aquifer in the state are LAFAYETTE UNION 2 \
ble 1. The Floridan aquifer underlies most of the State and ; 1 2 CT JO
ncipal source of water for municipal, industrial, and \ 4 JOHNS
use (see fig. 1). Other aquifers include: the Biscayne aquifer I2 1' N
eiies about 3,500 square miles in Dade, Broward, and Palm J I
nties; the shallow-sand aquifer and others which underlie ) /
southwest coast, south-central Florida and the eastern coast A t ,A
from Martin County into St. Johns County; and the D A CHUA -
gravel aquifer which underlies 2,000 square miles in I \
anta Rosa, and part of Walton Counties. / -

TYPES OF DATA COLLECTED Taw -O- ILEE L
T.5i l.-Pnq..ooy 08 ....eui.nt .04 .mplg Moce, vo., 0,5 ow mlop or owinma we a 2 E
el measurements are made on a continuous or periodic WATER LEVELS SAMPLING FOR CHEMICAL ANALYSIS AQUIFER OWNERSHIP
frequency of measurement is determined primarily by the Number Number NOumber Number 7
record. Measurements are made over a period of time to IruncO f w. Fquency of we, SN of wel Ctego of we 5
ends and fluctuations caused by m an or by natu re. Som e of G ~ ~ 2 6. --- I 551 582M O
h Contmuous 261 Continuous 3 Flondan 551 US.G.S. 582 i MARION
that can cause shor-tem fluctuations in level a m1re: VOLUSIA 3
n, earthquakes, barometric pressure changes, earth tides, 2 4 176 A01 3 Bayne 3 Ppa1ely3 n,"0 257
r recharging activities, and evapotranspiration. Long-term sem m3.2 302 SemBannAl 252 ,and88l 13 MuMp,.ie. il l
Is or trends of ground-water level are caused by seasonal and 28 B 6 \
matic change and continual pumping. Generally, such Bony 288 noniMy 63 No t ia 167 Co np -& 88 \
set the aquifer over a large area. LAKE
measurements are primarily used to determine seasonal, Other cludes
d long-term trends in water-level fluctuation. Types of yqIy, (ther de, a. a, CITRUS
measurements include annual, semiannual, quarterly, n3termtenty, quteymonhly, HaIhomoTampa, Sate&Gov 27 1 .
monthly, weekly, daily, and intermittent or irregular (table ..6,64y> 33 m.mit,,- 108 T 0 114 A.e/ 504 4 5 10 /

measurements are used to identify year-to-year changes; S EMIo
measurements depict seasonal highs and lows; bimonthly HERNANDO -
nts show seasonal trends; monthly and weekly ORANGE
its reveal month-to-month trends in water levels. Knowledge 1
is of great importance, for example, to city water i .
cents, as a guide in setting up pumping schedules involving Tbte 2.-soi0 num,8. of S.bailo or m Usf Gtelogi c -
rate well fields. Survey d the Florida Be Gology con 15 "--d-o
ion to the water-level monitoring network, an extensive ( a"teS tGOf io sAl,.ted tha 5or& fPi h yI 1933"70 PA CO
round-water network is maintained by the U.S. Geological ,.o o or S c- 26 12r o 4
Florida. Water samples were being collected for chemical 1..
om 509 wells in 34 counties as of January 1974 (table 1). Number Nibe, N ,mbr < 5
of analysis is dependent upon the purpose for which the Y wsp IC Y ea wsP IC y,_, wsP Ic 21 '
I be used. oin 4 fOSE-o o 0

base for chemical characteristics of waters or to type the 1936 7 949 27 S190oR-
lch aquifer and area; (2) signal by changes in composition the 1937 840 949 I.157 961 03 4l IN D I I
of salt water into an aquifer with subsequent deterioration 1939 s 19510 1 1962 3 03 4 POLK
(3) detect the presence of man-made pollutants; and (4) 1940 907 192 222 1964 197 0
ort and long-term changes in water quality. 141 937 1953 266 96 1978 61
rmical constituents of water usually analyzed are: silica, 194 987 1955 1405 1967 1978 68 INDIAN
dium, potassium, carbonate, bicarbonate, sulfate, chloride, 194 / 1 -- 1-0 \ 1
itrate, nitrite, hardness, noncarbonate hardness, alkalinity, 1945 1024- 197 15 1969 2 6
specific conductance, dissolved solids, temperature, color, '942 0 2 0 0 is 4EC- ~ o BE MANATEE HIGHLAN S
under special circumstances, analyses may include: phosphate, *A ief deptonof proets availability of eets
minum, iron, manganese, copper, lead, zinc, bromide, iodide, rKefoie936isgenonp. 42ofWSP777. I EECHOBEE 2
pounds, insecticides, herbicides, and radiochemicals. 5 5
aes of sampling of wells for chemical analyses are similar to ---- ST. LUCIE
measuring water levels (table 1). Sampling frequencies range s ARA 5
al to continuous. Chemical analyses range in detail from 6 DESOTO
analyses annually, to partial analyses in which only one or a f M T 7 ~-
tuents such as chloride and specific conductance are DESOTO % 4
. The temperature of water from wells in some areas is also L A B M a MARTIN 2
and recorded. Continuous analyses are made by recorders i I
atically analyze and record several chemical constituents s G E 0 G Lake
usly. E O4R ,G AC\

\--- 1.H U lTO, f U -CHARLOTTE 1

ds obtained from the observation well-program in Florida
inception of the program in 1930, are available to the public.. L l -
nts made in 1930-31 in Sarasota County were published in ET 0 t S"wN 3
State Geological Survey's Twenty-third and Twenty-fourth I4 -UL ( -
orts, in 1933. Measurements made in 1930-34 in other parts N 19ETT 5l\ HENDRY BEACH
were published in U.S. Geological Survey Water-Supply E LEE
4C. Records of water levels in wells in the statewide iE .LA' 8
ion network, including records for 1933-36, were first 19 9
n W ater-Supply Paper 817. O .1. L 3 '
nuary 1974 records of water level in selected wells in Florida j L E' A- 0- --'
able in Water-Supply Papers for 1933-68 and in Florida
Geology Information Circulars for 1960-70. Table 2 lists the I lE \ 30 R-----
bers of both publications for each of the given years of -~o- ARD
Water-Supply Papers containing these records are entitled, CITUS LE
fater Levels in the United States," in 6 parts by geographical-
the county. Records for wells in Florida are in "Part 2, COLLIER
mn States." Parts were not designated before 1940. Formerly I 0 one __.r- -
series, the current publication program provides for 5 years 53 j |A, P
n one volume for each geographical section. The calendar EXPLANATION I c o -
to 1960 span a transition period whereby 4 of the volumes IN 42
ntain 5 years of record. Each Information Circular of the GROUND-WATER USE-PUMPAGE EXCEEDS 8 MGD EXPLANATION 125
reau of Geology contains 2 years of record, as shown ini" oLll quality of-ground water
rhese repo rts are en ti tled "W ater L evels in A rtesian an d I M u n icipsal t si e asn w t MONJRO E 1 7 3
SAquifers in Florida." Records generally duplicate those pal (Observation-well network and quality round water 2 DADE
n the Water-Supply Papers. I -- sampling sites as of January 1974.) 2
on to this published material, a list of water levels in selected Industrial ..... E
orida is compiled monthly, in duplicated form. Copies of 9 Continuous ground-water stage recorder.
as well as data collected as part of project investigations, ae Irrigation
om the District Chief, US. Geological Survey, 325 John Periodic water-level measurement
F 2 4 0 T a l l a h a s s e e F l o r id a 3 2 3 0 3 M A J O R G R O U N D W A T E R S O U R C E S Ge rEd i wAn u l I l e

SELECTED REFENCES 1 i 6 Annually
Floridan Aquifer
.s. E" "" 2 Semiannually
(McKichan, K.A., and Pride,R.W.) The witer mapping, Biscayne Aquifer
monitoring and research program in Florida: State Board Bimonthly or other frequency
of Conserv., Florida Geol. Survey, Spec. Pub. 13. Sand-And-Gravel Aquifer
1.


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