Ground-water resources of the Stuart area, Martin County, Florida ( FGS: Information circular 12 )

STATE OF FLORIDA
STATE BOARD OF CONSERVATION
Ernest Mitts, Director

FLORIDA GEOLOGICAL SURVEY
Robert O. Vernon, Director

INFORMATION CIRCULAR NO. 12

GROUND-WATER RESOURCES OF THE STUART AREA,

MARTIN COUNTY, FLORIDA

By
W. F. Lichtler

Prepared by
U. S. Geological Survey
in cooperation with the
Central and Southern Florida Flood Control District
and the Florida Geological Survey

Tallahassee, Florida
1957

TABLE OF CONTENTS

Page

Abstract ......................... 1
Introduction . . . . . 2
Purpose and scope of investigation . .. 2
Previous investigations . . . 3
Personnel and acknowledgments . . 3
Location and general features of the area . 4
Geography and topography. . . . 4
Clim ate . . . . . 4
Geologic formations and their water-bearing
properties . . . . . 12
Eocene series . . . .... ... 12
Lake City limestone . . . 12
Avon Park limestone . . . .. 12
Ocala group. ..................... 13
Oligocene series. .................... 13
Miocene series ................... 13
Hawthorn formation .... ... ........ 13
Tamiami formation................... 14
Post-Miocene deposits. . . . ... 14
Ground water ...................... 14
Principles of occurrence .............. 14
Hydrologic properties of the aquifers. . .. .15
Floridan aquifer . . . .... 15
Nonartesian aquifer ............... 16
Thickness and areal extent .. ....... 16
Lithology .. .. ..... .. .. .. 16
Shape and slope of the water table ..... 18
Water-level fluctuations . .... 18
Ground-water use ... .............. 19
Quantitative studies. . . . . ... 21
Principles . . . .... ... .. 21
Descriptions of pumping tests. . . ... 23
Interpretation of'pumping-test data. . ... 24
Salinity studies ..................... 26
Contamination from surface-water bodies ..... .27
Contamination from artesian aquifer . ... 34
Summary and conclusions ............... 36
References .......... ....... ... 45

ILLUSTRATIONS

Figure Page
1 Map of Florida showing the Stuart area
and Martin County ................ 5
2 Map of the Stuart area showing the
locations of selected wells . . 6
3 Contour map of the water table in the
Stuart area, July 6, 1955. . . 7
4 Contour map of the water table in the
Stuart area, October 5, 1955. . . 8
5 Contour map of the water table within the
Stuart city limits, April 1, 1955 . . 9
6 Contour map of the water table within the
Stuart city limits, May 3, 1955. . ... 10
7 Hydrograph of well 147, in Stuart, and
daily rainfall at Stuart, 1954 . ... 20
8 Drawdown observed in wells 658 and 658A
during pumping test in the new city well
field, May 27, 1955. ............... 25
9 Map of the Stuart area showing the chloride
content of water from wells .......... 28

Table
1 Average temperature and rainfall at Stuart 11
2 Pumpage from Stuart well field, in millions
of gallons per month .............. 22
3 Chloride concentration in water samples
from selected wells.. .... ... .. . 29
4 Records of selected wells. ............ 38

SGROUND-WATER RESOURCES OF THE STUART AREA,

MARTIN COUNTY, FLORIDA

By
W. F. Lichtler

ABSTRACT

A shallow, nonartesian aquifer is the principal source
of water supplies in the Stuart area. This aquifer extends
from the landsurface to a depth of about 130 feet. It is com-
posed of the Pamlico sand and the Anastasia formation of
Pleistocene age, the Caloosahatchee marl of Pliocene age,
and possibly part or all of the Tamiami formation of Miocene
age.

The aquifer differs in lithology and texture from place
to place but, in general, wells less than 40 feet deep require
screens. Consolidated beds of differing thicknesses usually
occur between 40 and 130 feet below the land surface, and
open-hole wells usually canbe completed somewhere in this
interval. At' depths below 130 feet the relatively imperrrie-
able sands and clays of the Hawthorn formation (Miocene)
are encountered and little water is available. Beneath the
Hawthorn formation, limestones in the Floridan aquifer, 600
to 800 feet or more below mean sea level, contain water under
pressure. The deep artesian water contains 800 to 4, 200
ppm of chloride in the Stuart area and is too salty for most
purposes.

Periodic determinations of the chloride content of water
from wells indicate that there has been some salt-water en-
croachment into the shallow aquifer in the areas adjacent to
the St. Lucie River and some contamination resulting from
leakage through faulty casings of wells that penetrate the
Floridan aquifer.

FLORIDA GEOLOGICAL SURVEY

The coefficient of transmissibility of the shallow aquifer
as computed from pumping-test data by the Theis nonequi-
librium method ranged from 18, 000 to 170, 000 gallons per
day per foot (gpd/ft). The wide range in values is believed
to indicate notan actual condition but that the aquifer is not
suitable for a normal Theis analysis. Further analyses of
the data by the leaky-aquifer method developed by Hantush
and Jacob (1955, p. 95-100) and by use of an unpublished
leaky-aquifer "type curve" developed by H. H. Cooper, Jr.,
yielded a transmissibility value of about 20, 000 gpd/ft.

The average height above mean sea level of the water
table in the shallow aquifer is enough, at the present time,
to prevent extensive salt-water encroachment into the aqui-
fer. Unless the water table is lowered excessively by drain-
age ditches or'heavy pumping, a permanent supply of fresh
water is assured. Large quantities of fresh water are avail-
able for future development in the central part of the Stuart
peninsula.

INTRODUCTION

Purpose and Scope of Investigation

Because the Stuart area is, at times, surrounded on three
sides by saline water, the underlying fresh-water aquifer is
vulnerable to salt-water encroachment. With progressively
larger withdrawals of ground water for public and private
supplies, the possibility of salt-water contamination of fresh-
water supplies is increased.

The Central and Southern Florida Flood Control District
requested that the U. S. Geological Survey investigate the
ground-water resources of the area and determine the extent
of salt-water encroachment. The investigation was made as
a part of the general-studies in cooperation with the Flood
Control District and the Florida Geological Survey. Pre-
liminary work, including the inventorying of and collection
of water samples from a large number of wells in Martin
County, was done during 1953 by E. W. Bishop, formerly
with the U. S. Geological Survey. Intensive field work by

FLORIDA GEOLOGICAL SURVEY

The coefficient of transmissibility of the shallow aquifer
as computed from pumping-test data by the Theis nonequi-
librium method ranged from 18, 000 to 170, 000 gallons per
day per foot (gpd/ft). The wide range in values is believed
to indicate notan actual condition but that the aquifer is not
suitable for a normal Theis analysis. Further analyses of
the data by the leaky-aquifer method developed by Hantush
and Jacob (1955, p. 95-100) and by use of an unpublished
leaky-aquifer "type curve" developed by H. H. Cooper, Jr.,
yielded a transmissibility value of about 20, 000 gpd/ft.

The average height above mean sea level of the water
table in the shallow aquifer is enough, at the present time,
to prevent extensive salt-water encroachment into the aqui-
fer. Unless the water table is lowered excessively by drain-
age ditches or'heavy pumping, a permanent supply of fresh
water is assured. Large quantities of fresh water are avail-
able for future development in the central part of the Stuart
peninsula.

INTRODUCTION

Purpose and Scope of Investigation

Because the Stuart area is, at times, surrounded on three
sides by saline water, the underlying fresh-water aquifer is
vulnerable to salt-water encroachment. With progressively
larger withdrawals of ground water for public and private
supplies, the possibility of salt-water contamination of fresh-
water supplies is increased.

The Central and Southern Florida Flood Control District
requested that the U. S. Geological Survey investigate the
ground-water resources of the area and determine the extent
of salt-water encroachment. The investigation was made as
a part of the general-studies in cooperation with the Flood
Control District and the Florida Geological Survey. Pre-
liminary work, including the inventorying of and collection
of water samples from a large number of wells in Martin
County, was done during 1953 by E. W. Bishop, formerly
with the U. S. Geological Survey. Intensive field work by

INFORMATION CIRCULAR NO. 12

the writer began in January 1955 and continued through Au-
gust 1955. Samples of water from wells in the area were
analyzed to determine their chloride content. Wells suit-
able for a program of periodic measurement of water levels
were selected. A special effort was made to include in this
program only wells that were not in use, so that all wells
could be measured in a single day to obtain an "instantaneous"
picture of the water table. The altitudes of all measuring
points in observation wells were determined by spirit level
and referred to U. S. Coast and Geodetic Survey mean-sea-
leveldatum, and water-table contour maps were drawn from
the data.

Previous Investigations

No detailed investigations of ground-water resources in
Martin County had been made prior to the present investi-
gation. Brief references to Martin County were made by
Mansfield (1939), Parker and Cooke (1944), Cooke (1945),
Matson and Sanford (1913), Collins and Howard (1928),
Stringfield(1936), and Parker, Ferguson, Love, and others
(1955). In addition, references were made to water levels
in Water-Supply Papers 1166, 1192, 1222; and to quality-of-
water data by Black and Brown (1951), and Black, Brown,
and Pearce (1953).

Personnel and Acknowledgments

The writer wishes to express his appreciation for the
assistance and cooperation of the residents of the Stuart
area, who supplied many valuable data and permitted the
sampling and measuring of wells. Joseph Greenlees, City
Manager; Frederick Walton, Water Commissioner; Ernest
Tyner, City Commissioner; and James Doyle, County Sani-
tarian, were helpful during the investigation. Douglas Arnold,
well driller of Stuart, and Charles A. Black of Black and
Associates, Gainesville, Florida, supplied much valuable
geologic and hydrologic information.

The investigation was under the general supervision of
A. N. Sayre, Chief, Ground Water Branch, and under the
immediate supervision of N. D. Hoy, Geologist, and M. I.
Rorabaugh, District Engineer, all of the U. S. Geological
Survey.

FLORIDA GEOLOGICAL SURVEY

LOCATION AND GENERAL FEATURES OF THE AREA

Geography and Topography

The area covered by this report includes most of the
city of Stuart and adjacent parts of Martin County (fig. 1).
Most of Stuart is on a peninsula formed by the South Fork of
the St. Lucie River on the west, the St. Lucie River on the
north, and the St. Lucie River and Manatee Pocket on the
east (fig. 2). The peninsula is about four miles wide at its
base, about three miles wide at its northern end, and about
four miles long,

The land surface generally ranges from 10 to 20 feet in
altitude in the central part of the peninsula. It slopes gently
to the banks of the South Fork of the St. Lucie River on the
western side and to relatively steep banks along the St. Lucie
River on the northern and eastern sides.

The entire peninsula is covered by permeable quartz
sand, about 40 feet thick. Drainage is predominantly under-
ground. Rainfall infiltrates rapidly through the permeable
surficial sand to the water table and flows approximately at
right angles to the water-table contours (fig. 3-6) to points
of discharge along the coast or into several small streams.
The water table is near the surface inthe central part of the
peninsula during much of the year, and during high ground-
water stages surface lakes exist in depressions scattered
throughout the area.

Climate

The climate at Stuart is subtropical, the average annual
temperature being 75.40 F. Because of the moderating in-
fluence of the surrounding water, the temperature is usually
two to four degrees higher during winter cold spells than in
areas farther inland, and somewhat lower in the summer.
Rainfall averages 56. 3 inches per year. Table 1 shows that
rainfall is greatest in late summer and early fall and least
in the winter.

INFORMATION CIRCULAR NO. 12

Map of Florida showing the Stuart area and Martin
County.

Figure 1.

FLORIDA GEOLOGICAL SURVEY

Figure 2. Map of the Stuart area showing the locations of
selected wells.

INFORMATION CIRCULAR NO. 12

Contour map of the water table in the Stuart area,
July 6, 1955.

Figure 3.

FLORIDA GEOLOGICAL SURVEY

Figure 4. Contour map ofthe watertable in the Stuart area,
October 5, 1955.

INFORMATION CIRCULAR NO. 12

Figure 5. Contour map of the water table within the Stuart
city limits, April 1, 1955.

10 FLORIDA GEOLOGICAL SURVEY

Figure 6. Contour map of the water table within the Stuart
city limits, May 3, 1955.

INFORMATION CIRCULAR NO. 12

Table .. Average Temperature and Rainfall at Stuart

Month

Jan.

Feb.

Mar.

Apr.

May

June

July

Aug.

Sept.

Oct.

Nov.

Dec.

Yearly average

Temperature
(F.)

66.9

67.7

70.9

74.4

77.6

81.4

82.4

83.0

81.7

78. 1

72.2

68.4

75.4

1Discontinuous record 1936-1955,
2Discontinuous record 1935-1955,
2Discontinuous record 1935-1955,

U. S. Weather Bureau.
U.S. Weather Bureau.

Rainfall2
(inches)

1.92

2.32

2.86

3.15

4.52

6.75

6.30

5.47

9.81

8.73

2.44

2.03

56.30

FLORIDA GEOLOGICAL SURVEY

GEOLOGIC FORMATIONS AND THEIR
WATER-BEARING PROPERTIES

The strata underlying the Stuart area to a depth of about
1,000 feet range in age from Recent at the surface to middle
Eocene at the bottom. Water in the formations older than
Miocene is highly mineralized and is used very little in the
Stuart area. The formations of Miocene age yield only small
quantities of water. Most wells are developed in post-Miocene
sediments.

Eocene Series

The oldest rocks penetrated by water wells in the Stuart
area are of middle Eocene age. The Eocene rocks include
the Lake City limestone and the Avon Park limestone of
Claiborne age and the Ocala group of Jackson age; these form
the lower and major part of the Floridan aquifer (p. 15).

Lake City Limestone

The Lake City limestone, as defined by Cooke (1945,
p. 46-47), overlies the Oldsmar limestone of Wilcox age in
northern Florida and is overlain by the Tallahassee lime-
stone. The Tallahassee limestone apparently is missing in
southern Florida. The Lake City limestone in northern and
central Florida is described as alternating layers of dark
brown chalky limestone with some gypsum and chert. It
forms part of the Floridan aquifer, and in the central part
of Martin County it is tapped for irrigation and stock-watering
supplies.

Avon Park Limestone

The Avon Park limestone, also a part of the Floridan
aquifer, overlies the Lake City limestone. It is a cream
colored to white, chalky to granular, porous limestone that
ranges in thickness from about 100 to 150 feet in central
Florida.

INFORMATION CIRCULAR NO. 12 13

Ocala Groupl

The Ocala group unconformably overlies the Avon Park
limestone and is another part of the Floridan aquifer. It is
a cream colored, soft to hard, porous limestone, with beds
of coquina at some localities.

Oligocene Series

The Oligocene series in Martin County has not been
clearly defined. Sediments overlying the Ocala group and
underlying the Hawthorn formation have been tentatively
classified as of Vicksburg (middle Oligocene) age in the
Stuart area and as of Suwannee (late Oligocene) age in south-
eastern Martin County. A correlation of cuttings from wells
in the area indicates that there may have been some post-
Oligocene faulting. The Vicksburg group in the Stuart area
is composed of cream colored, softtohard, granular, porous
limestone and some sand and shells. It forms the upper part
of the Floridan aquifer in this area.

Miocene Series

The Miocene series in the Stuart area includes 'the
Hawthorn formation of middle Miocene age and the Tamiami
formation of late Miocene age. The Tampa limestone :of
early Miocene age may be present below the Hawthorn for-
mation, but this has not been clearly established.

Hawthorn Formation

The Hawthorn formation is composed of olive-drab,
relatively impermeable clay and sand and some thin lenses

IThe stratigraphic nomenclature used in this report
conforms to the usage of the Florida Geological Survey. It
also conforms to the usage of the U.S. Geological-Survey
with the exception of the Ocala group and its subdivisions'.
The Florida Survey has adopted the Ocala group as described
by Puri (1953). The Federal Survey regards the Ocala as a
formation, the Ocala limestone.

FLORIDA GEOLOGICAL SURVEY

of limestone. In the Stuart area it is about 350 feet thick.
A test well in the new city well field penetrated greenish
sand at a depth of about 150 feet that is believed to be part
of the Hawthorn formation. The Hawthorn formation forms
the major part of the upper confining bed of the Floridan
aquifer.

Tamiami Formation

The Tamiami formation appears to be conformable with
the underlying Hawthorn formation. In the Stuart area it is
composed of about 60 feet of sand, shell fragments and lime-
stone. Part or all of the Tamiami formation may form an
extension of the shallow nonartesian aquifer in the post-
Miocene deposits, and part may be included in the confining
bed above the Floridan aquifer.

Post-Miocene Deposits

The post-Miocene deposits include the Caloosahatchee
marl of Pliocene age and the Anastasia formation and Pam-
lico sand of Pleistocene age. The boundary between the
Pliocene and Pleistocene in this area could not be determined,
owing to the fact that the Caloosahatchee marl and the Anas-
tasia formation are lithologically similar in Martin County.
This boundary can be determined definitely only by detailed
examination of the fossils of the formations.

A thin layer of quartz sand of the Pamlico sand covers
the area and grades into the underlying Anastasia formation.

GROUND WATER

Principles of Occurrence

Ground water is stored in the joints, solution cavities,
pore spaces, and other openings of the earth's crust below
the water table. Ground water is the subsurface water in
the zone, called the zone of saturation, in which all openings
are completely filled with water under pressure greater than
atmospheric. The water table is the top of this zone.

INFORMATION CIRCULAR NO. 12

Only part of the water that falls as rain reaches the
zone of saturation. The remainder runs off the land surface
to open bodies of water such as rivers, lakes and bays, or
is returned to the atmosphere by evaporation and transpi-
ration. The amount of rain that reaches the water table
depends on many factors. These include the rate at which
the rain occurs, the slope of the land on which it falls, the
amount and type of vegetation cover, and the character of
the surface materials throughwhich the water must infiltrate
to reach the zone of saturation.

After the water reaches the zone of saturation it begins
to move more or less laterally, under the influence of gravity,
toward a point of discharge such as a spring or well. Ground
water may occur under either artesian or nonartesian (water-
table) conditions. Where the water is confined in a permeable
bed that is overlain by a relatively impermeable bed, its
surface is not free to rise and fall. Water thus confined under
pressure is said to be under artesian conditions. The term
"artesian" is applied to ground water that is confined under
pressure sufficient to cause the water to rise above the top
of the permeable bed that contains it, though not necessarily
above the land surface. Where the upper surface of the water
is free to rise and fall in a permeable formation, the water
is said to be under nonartesian conditions, and the upper
surface is called the water table. All gradations exist be-
tween artesian and nonartesian conditions.

Hydrologic Properties of the Aquifers

Ground water in the Stuart area occurs in two major
aquifers, a deep artesian aquifer (Floridan aquifer), and a
shallow nonartesian aquifer. The aquifers are separated by
a thick section of relatively impervious clay and sand. The
water inthe artesian aquifer is much more mineralized than
that in the nonartesian aquifer.

Floridan Aquifer

Wells penetrating the Floridan aquifer in the Stuart area
range in depth from 800 tol, 200 feet. The pressure head in
these wells is about 40 feet above the land surface, or about

FLORIDA GEOLOGICAL SURVEY

of limestone. In the Stuart area it is about 350 feet thick.
A test well in the new city well field penetrated greenish
sand at a depth of about 150 feet that is believed to be part
of the Hawthorn formation. The Hawthorn formation forms
the major part of the upper confining bed of the Floridan
aquifer.

Tamiami Formation

The Tamiami formation appears to be conformable with
the underlying Hawthorn formation. In the Stuart area it is
composed of about 60 feet of sand, shell fragments and lime-
stone. Part or all of the Tamiami formation may form an
extension of the shallow nonartesian aquifer in the post-
Miocene deposits, and part may be included in the confining
bed above the Floridan aquifer.

Post-Miocene Deposits

The post-Miocene deposits include the Caloosahatchee
marl of Pliocene age and the Anastasia formation and Pam-
lico sand of Pleistocene age. The boundary between the
Pliocene and Pleistocene in this area could not be determined,
owing to the fact that the Caloosahatchee marl and the Anas-
tasia formation are lithologically similar in Martin County.
This boundary can be determined definitely only by detailed
examination of the fossils of the formations.

A thin layer of quartz sand of the Pamlico sand covers
the area and grades into the underlying Anastasia formation.

GROUND WATER

Principles of Occurrence

Ground water is stored in the joints, solution cavities,
pore spaces, and other openings of the earth's crust below
the water table. Ground water is the subsurface water in
the zone, called the zone of saturation, in which all openings
are completely filled with water under pressure greater than
atmospheric. The water table is the top of this zone.

FLORIDA GEOLOGICAL SURVEY

50 feet above mean sea level. Large flows are obtained
from wells penetrating the aquifer, but the water is highly
mineralized, ranging in chloride content from 800 to 4, 200
ppm. Because of its high mineral content, little use is made
of the artesian water in the Stuart area. The availability
and quality of the water from the Floridan aquifer in Martin
County will be discussed more thoroughly in a later report.

Nonartesian Aquifer

Thickness and areal extent: The nonartesian aquifer is
composed, from the surface down, of the Pamlico sand, the
Anastasia formation, the Caloosahatchee marl, and possibly
the Tamiami formation. The aquifer extends from the land
surface to a depth of about 130 feet and is underlain by im-
permeable sand and clay which is probably part of the Haw-
thorn formation.

The bodies of salt water that bound the peninsula on the
east, north and west are the boundaries of the nonartesian
aquifer. Excessive lowering of the water table near these
boundaries would cause salt water to move in laterally. To
the south, however, the aquifer has a much greater areal
extent.

Lithology: Data obtained from the inventory of wells in
the area show a wide range in the depth of nonartesianwells,
a fact which indicates that the lithology of the nonartesian
aquifer differs from place to place. The heterogeneity of
the aquifer is evident in well cuttings from a few wells drilled
in the area during the course of this investigation. Permeable
rock and shell are separated by less permeable fine sand or
marl. Beds found at a given depth'at one site may be found
at a different depth or maybe missing entirely at another site
close by. Sufficient information is not yet available to define
accurately the various permeable zones, but a generalized
geologic section of the area is shown in the following log:

INFORMATION CIRCULAR NO. 12

Depth, in
feet, below
Description land surface

Sand, quartz, fine to coarse, cream colored,
gray and brown, clear to frosted, rounded
and subangular. ................. ....... 0 20

"Hardpan"; sand, quartz, cream colored to
brown, contains cream colored to brown
clay.................. .................. 20 23

Sand, quartz, fine to coarse, tan to dark gray 23 40

Sandstone, friable, loosely cemented, and
some shell fragments ................... 40 48

Sand, quartz, very fine to fine, dark gray,
micaceous ............................. 48 58

Limestone and sandstone, tan-graytobluish,
hard, porous; contains some shells. Per-
meability relatively high. Many open-hole
wells are finished in this section in the north-
ern part of the Stuart area............... 58 73

Sand, quartz, fine, tan to gray, some shell
fragments ..... ........................ 73 80

Limestone and sandstone, buff-brown, hard,
interbedded with medium quartz sand and
shell fragments ........................ 80 88

Sand, quartz, very fine to fine, tan to gray,
contains phosphatic nodules and some shells 88 103

Limestone and sandstone, fine grained, dense,
hard;interbeddedwith fine to medium round-
ed quartz sand and shell beds.............. 103 123

Sand, quartz, fine to medium; few shell frag-
m ents .................................. 123 133

FLORIDA GEOLOGICAL SURVEY

Limestone and sandstone, interbedded with
medium quartz sand and shells ............ 133 144

Sand, very fine to fine, greenish-gray...... 144 151

The layers or lenses of fine sand retard the vertical
movement of water.

Shape and slope of the water table: The water levels in
observation wells were measured at various times to deter-
mine the altitude and shape of the water table in the area
and to determine changes in ground-water storage in the
aquifer.

The water table is highest in the south-central part of
the peninsula and slopes east, north, and west toward points
of ground-water discharge in the Manatee Pocket, the St.
Lucie River, and the South Fork of the St. Lucie River (fig.
3,4). Because ground water flows approximately at right
angles to the contour lines, it is apparent from figures 3
and 4 that practically all the recharge to the nonartesian
aquifer in the peninsula is derived from local rainfall. Much
of the rainfall is quickly absorbed by the permeable surface
sands and infiltrates to the water table. Evidence for this
lies in the fact that the water level in a well 144 feet deep
rose 1. 11 feet within 12 hours after a rainfall of 1.09 inches
was recorded at Stuart. Surface runoff is small, except lo-
cally after exceptionally heavy rainfall.

Figures 5 and 6 show how the water table was lowered
by pumping in the city well fields. Figure 5 shows the water
table on April 1, 1955, when the city wells at the old city
well field, at the water plant and the ball park, were pump-
ing. Figure 6 shows the water table on May 3, 1955, when
wells were shut down in the old well field and wells were
pumping in the new city well field, south of 10th Street and
west of Palm Beach Road.

Water-level fluctuations: Threewells inthe eastern part
of Martin County are equipped with automatic water-level
gages which provide a continuous record of the fluctuations
of the water table. Only one of these (well 147) is in the area

INFORMATION CIRCULAR NO. 12

of this report (fig. 2). Figure 7 is a hydrograph showing
fluctuations of the water level in well 147 during 1954.
Well 147 is 74 feet deep and is about a quarter of a mile
east of the new city well field. The maximum yearly range
in water level in this well for the period 1952-1955 was 6. 3
feet in 1953. This compares with a maximum yearly range
of 4. 8 feet in well 140, which is 16 miles south of well 147,
and 5.8 feet in well 125, which is 15 miles southeast of
well 147, in Jonathan Dickinson State Park.

Figure 7 shows also the distribution of rainfall as re-
corded at radio station WSTU, at Stuart, in 1954. As a
rule, the water level in well 147, which is about two miles
from the rain gage, correlates fairly closely with rainfall,
but a few exceptions are apparent. On February 2, 1954,
for example, a 1. 85-inch rainfall produced only a very slight
rise in the water level in well 147, but a 1.48-inch rainfall
on March 29 produced a rise of about 0. 3 foot. Doubtless
some of the rain falls in short, local showers that do not
wet all parts of the Stuart area. This would account for
some of the lack of correlation shown in figure 7.

Figures 3 and4 show the configuration ofthewater table
at high and low ground-water stages, respectively, in 1955.
Ground-water stages are usually highest during September
and October; however, rainfall in 1955 was exceptionally low
from August to November, and the usual high stages did not
occur. Thus, water levels on July 6, 1955 (fig. 3), were
higher than those on October 5 (fig. 4).

GROUND-WATER USE

Practically all the water for public, irrigation, do-
mestic, and industrial use in the Stuart area is obtained
from ground-water sources. Since April 25, 1955, all the
city supply has been obtained from three 4-inch wells (657,
723, 724), 125 feet deep, in the new city well field (fig. 2).
The wells are spaced about 600 feet apart and each is equipped
with a turbine pump having a capacity of 100 gpm. Prior to
April 25, 1955, the city supply was obtained from one 4-inch
and two 6-inch wells (97, 98, 99) about 65 feet deep, near
the water-treatment plant, and two 4-inch wells (621, 623)
56 feet deep, at the ball park. Operation of these wells was

FLORIDA GEOLOGICAL SURVEY

JAIL. P MAR. APR. MAY JUNE JULY AUO. SEPT. O T. NOV._ DE.

3, __

I .-- -- -- -- --.-- -- -- -

Lo

l l' .-- -- -- -- --_ -- -

Figure 7. Hydrographofwell 147, inStuart, and daily rain-
fall at Stuart, 1954.

INFORMATION CIRCULAR NO. 12

discontinued because of an increase in the salinity of the
water, but they are available for emergency use.

The pumpageby the city of Stuart has increased steadily
during the last few years as new customers have been added
(table 2). During 1955, 91 million gallons of water was
pumped. Water usage is high during dry periods when lawns
are irrigated.

The numerous flower farms in the vicinity of Stuart have
their own irrigation wells and use large quantities of ground
water duringthe growing season, from October to May. Some
of this irrigationwater returns to the ground-water reservoir
by infiltration through the surface sands.

In areas not serviced by city water mains, private wells
are used for both domestic supplies and irrigation. In ad-
dition, several hundred wells are used for lawn irrigation
within the area served by the city. Their total pumpage is
doubtless large, but no figures are available. Here, too,
some of the water is returned to the ground-water reservoir
by infiltration through the surface sands. The industrial use
of ground water in the Stuart area is small.

QUANTITATIVE STUDIES

Principles

The ability of an aquifer to transmit water is expressed
by the coefficient of transmissibility. In customary units,
it is the quantity of water, in gallons per day, that will move
through a vertical section of the aquifer one foot wide and
extending the full saturated height, under a unit hydraulic
gradient (Theis, 1938, p. 892), at the prevailing temperature
of the water. The coefficient of storage is a measure of the
capacity of the aquifer to store water and is defined as the
volume of water released from or taken into storage per unit
surface area of the aquifer per unit change in the component
of head normal to that surface. These coefficients are gen-
erally determined by means of pumping tests on wells.

N
N
Table 2. Pumpage From Stuart Well Field, in Millions of Gallons Per Month

Year Jan. Feb. Mar. Apr. May June July Aug, Sept. Oct. Nov. Dec. Total

1941 2.63 2.77 3.23 2.89 2.70 2.82 2.48 2.68 2.57 2.69 2.91 2.62 32.98
1942 3.26 3.54 3.29 3.26 3.67 3.24 3.40 3.30 3.06 3.47 3.48 3.53 40.51 0
1943 3.53 3.42 3.57 3.62 3.80 3.57 3.49 3.61 3.44 3.63 3.74 3.94 43.35
1944 3.93 4.04 4.41 4.36 4.38 4.29 3.88 3.50 3.40 3.23 3.28 3.63 46.31 >
1945 3.86 3.60 4.25 3.89 3.71 3.34 3.02 3.28 3.12 3.11 3.18 3.64 42.00 0
1946 3.91 3.85 4.00 4.30 3.40 2.94 3.05 3.21 3.16 3.80 3.55 3.86 43.04
1947 4.14 3.74 3.98 3.61 3.77 3.11 3.48 3.50 3.10 3.27 3.29 3.50 42.47
1948 3.61 4.36 5.00 4.56 4.14 3.74 3.53 3.41 3.25 3.79 4.04 4.22 47.65 0
1949 4.32 4.17 4.77 4.27 3.94 3.13 3.34 2.83 3.96 3.58 3.74 4.01 46.05
1950 4.00 4.84 5.18 4.56 4.79 4.12 4.15 4.28 5.00 4.90 4.81 5.78 56.43
1951 6.08 5.71 6.73 5.30 6.73 5.18 4.27 5.43 4.19 3.68 4.55 5.01 62.86
1952 6.11 5.39 4.76 4.98 5.20 5.39 5.54 5.75 5.59 5.90 5.59 5.56 65.74 C
1953 6.34 5.85 6.35 6.18 6.47 5.37 5.93 5.34 5.44 5.03 5.23 5.90 69.42
1954 6.42 6.65 6.75 6.48 6.40 6.26 5.89 6.70 5.82 6.34 6.75 7.57 78.02 M
1955 8.32 7.23 8.21 7.54 8.15 7.91 6.85 7.11 6.67 7.55 7.95 7.57 91.07

INFORMATION CIRCULAR NO. 12

Descriptions of Pumping Tests

Pumping tests were made at five places in the Stuart
area, four in the new city well field and one in the ball park
well field.

The first test was made in the new city well field on
March, 1955, withwell657 (city supply well No. 1) pumping
at the rate of 135 gpm for 11 hours. Water-level measure-
ments were made during the test in wells 656, 658 and 659,
located 11, 100 and 300 feet, respectively, from the pumped
well. All wells are cased to 115 feet with 10 feet of open
hole in the underlying limestone, except well 656, which is
cased to 144 feet with one foot of open hole. The water from
well 657 was discharged into a ditch about 75 feet from the
pumping well, but because the ditch was choked with vegetation
and has only a slight gradient, water remained in the vicinity
and recharged the aquifer during the test.

In the second test; made on March 23, 1955, also in the
new city well field, well 724 (city supply well No. 3), was
pumped at a rate of 140 gpm for five hours, and water levels
were observed in wells 659, 658 and 657, located 300, 500
and 600 feet, respectively, from the pumped well. The wells
are all cased to 115 feet, leaving 10 feet of open hole in the
underlying limestone. The water was discharged into a ditch
200 feet from the pumpedwell and again remained in the area
and recharged the aquifer, but this recharge did not affect
the water levels as early as that in test No. 1.

The following day, March 24, 1955, the third test
was made at: the 'same location as tests 1 and 2. Well 723
(city supply wellNo. 2)was pumped at a rate of 112 gpm for
five hours, and water levels were observed in wells 658 and
724, located 500 and 750 feet, respectively, from the pumping
well. All wells are cased to 115 feet, leaving 10 feet of open
hole in the underlying limestone. The water was discharged
into a depression near the wells and remained in the area,
probably recharging the aquifer.

SThe fourth testwas made on May 27, 1955, also in the new
well field, when the new wells were in operation. Observation

FLORIDA GEOLOGICAL SURVEY

well 658A, 13 feet deep, was installed 100 feet from well
657 (city supply well No. 1) and immediately adjacent to
observation well 658. Prior to the test the well field was
shut down overnight to allow recovery of the water levels
in the area. On the next morning the water levels in both
the deep and shallow observation wells were measured and
were 6.38 feet above mean sea level. Well 657 was pumped
at a rate of 105 gpm for nine hours, at the end of which
period the drawdowns in wells 658 and 658A were 3. 58 and
0. 34 feet, respectively (fig. 8). The water level in well 658
began to decline almost immediately after pumping started,
and had fallen three feet after 21 minutes. The water level
in shallow well 658A began to decline eight minutes after the
start of pumping, and had fallen 0. 07 foot after 21 minutes.
Near the end of the test the water level in well 658 had neatly
stabilized, whereas that in well 658A was still falling, but
at a decreasing rate. The water was discharged into the
city mains and so did not return to the aquifer.

The fifth test was made in the well field at the ball park
on April 27, 1955. Well 621 (city well No. 2) was pumped
at a rate of 130 gpm for five hours. Observation wells 620
and 623 were seven and 375 feet, respectively, from the
pumped well. All wells are cased to 51 feet, leaving five
feet of open hole in the underlying limestone. The water
was discharged on the ground in the immediate vicinity of
the pumped well and doubtless some returned to the aquifer
during the test.

Interpretation of Pumping -Test Data

Theis (1935, p. 519-524), using basic heat-transfer
formulas, developed a method to analyze the movement of
water through an aquifer under the conditions that the aquifer
is (1) homogeneous and isotropic, (2) of infinite areal extent,
(3) of uniform thickness, (4) bounded above and below by
impervious beds, (5) receiving no discharge, (6) fully pene-
trated by the discharging well, and (7) losing water only
through the discharging well. If an aquifer meets all these
conditions, the Theis nonequilibrium method, as described
by Wenzel (1942, p. 87-90), will give a true transmissibility
value for the aquifer regardless of the distance of the obser-
vation well from the pumped well or the rate of pumping.

INFORMATION CIRCULAR NO. 12

Drawdown observed in wells 658 and 658A during
pumping test in the'new city well field, May 27,
1955.

Figure 8.

FLORIDA GEOLOGICAL SURVEY

Whenthe data from the tests in the city well fields were
analyzed by the Theis method, the computed values of the
coefficient of transmissibility ranged from 18, 000 to 170, 000
gpd per foot for the same area, indicating that the aquifer
does not meet all the above conditions. The main producing
zone, which is between 103 and 140 feet (see well log) in the
new well field, is reasonably homogeneous, isotropic, and
uniform in thickness, judging from well logs and cuttings
and the performance of individual wells. For a test of short
duration the aquifer is, in effect, of infinite areal extent,
but it is not bounded above by an impermeable bed, as is
shown by the fact that the water level in shallow well 658A
(fig. 2) began to decline eight minutes after well 657 began
pumping (fig. 8). Also, the water was discharged on the
ground in the vicinity of the pumpedwells and, consequently,
the aquifer was receiving recharge. In addition, the aquifer
was not fully penetrated by the pumped wells. After correc-
tions were made for the effects of partial penetration and
also for the natural decline of the water table thatwas taking
place the data were further analyzed by means of the leaky-
aquifer method of Hantush and Jacob (1955, p. 95-100) and
a leaky-aquifer type curve developed by H.H. Cooper, Jr.,
of the U. S. Geological Survey, Tallahassee, Florida, (per-
sonal communication). This analysis produced values for
the coefficient of transmissibility ranging from 15,000 to
25, 000 gpd per foot, with a probable average near 20, 000
gpd per foot. This seems to be a reasonable coefficient of
transmissibilityfor the main producing zone of the aquifer.
When considering long-term pumping, vertical leakage from
the overlying beds is an important factor, and the coefficient
of transmissibility of the overlying beds should be added to
that of the main producing zone to obtain a realistic coefficient
of transmissibility for the well field.

SALINITY STUDIES

The chloride content of ground water is generally a
reliable index of the extent of contamination by salt water
from the sea or other sources. Water samples were collected
from severalhundred wells in the Stuart area for chloride
analysis (fig. 9). Those wells yieldingwater having anappre-
ciable chloride content were sampled periodically to detect
any variations in the chloride content of the water (table 3).

INFORMATION CIRCULAR NO. 12

discontinued because of an increase in the salinity of the
water, but they are available for emergency use.

The pumpageby the city of Stuart has increased steadily
during the last few years as new customers have been added
(table 2). During 1955, 91 million gallons of water was
pumped. Water usage is high during dry periods when lawns
are irrigated.

The numerous flower farms in the vicinity of Stuart have
their own irrigation wells and use large quantities of ground
water duringthe growing season, from October to May. Some
of this irrigationwater returns to the ground-water reservoir
by infiltration through the surface sands.

In areas not serviced by city water mains, private wells
are used for both domestic supplies and irrigation. In ad-
dition, several hundred wells are used for lawn irrigation
within the area served by the city. Their total pumpage is
doubtless large, but no figures are available. Here, too,
some of the water is returned to the ground-water reservoir
by infiltration through the surface sands. The industrial use
of ground water in the Stuart area is small.

QUANTITATIVE STUDIES

Principles

The ability of an aquifer to transmit water is expressed
by the coefficient of transmissibility. In customary units,
it is the quantity of water, in gallons per day, that will move
through a vertical section of the aquifer one foot wide and
extending the full saturated height, under a unit hydraulic
gradient (Theis, 1938, p. 892), at the prevailing temperature
of the water. The coefficient of storage is a measure of the
capacity of the aquifer to store water and is defined as the
volume of water released from or taken into storage per unit
surface area of the aquifer per unit change in the component
of head normal to that surface. These coefficients are gen-
erally determined by means of pumping tests on wells.

INFORMATION CIRCULAR NO. 12

In most cases the fluctuations are caused by variations in
the amount of rainfall in the area or an increase or decrease
in pumping. Usually it is a combination of the two, because
more water is needed for irrigation during dry periods, as
in 1955, and less during wet periods, as in 1947-1948.

In a few cases, notably inwells 647 and 722, the chloride
content of the water dropped during a dry period, owing to
the cessation of pumping in the old city well field and the
plugging of a leaky artesian well, No. 128 (fig. 2). Wells 619
and 654 showed an increase and then a decrease in the chlo-
ride content of the water. The decrease was probably caused
by the flushing of the salty artesian water from the aquifer.

Salt water may encroach into the Stuart area from either
of two sources: (1) bodies of seawater, including the St. Lucie
River, the Manatee Pocket, and tidal creeks and canals, and
(2) the artesian aquifer.

Contamination from Surface-Water Bodies

Encroachment from the St. Lucie River and the Manatee
Pocket is not extensive at the present time. It has occurred
only in areas near the coast, and no proven encroachment
has been found more than half a mile from the river. The
fresh-water head is high close to the shoreline, and in many
places fresh water canbe obtained from wells within 100 feet
of salt-water bodies. It is reported that fresh water has
been obtainedfrom wells driven in the river bottom, but the
author has not confirmed this.

Heavy pumping in the areas adjacent to the river may
cause sufficient lowering of theater table to allow saltwater
to invade the fresh-water zone. Water of high chloride content
was detected in well 720, about 1,500 feet from the St. Lucie
River, about halfway between the river and the water plant
well field. When the wellwas drilled, water containing 9, 180
ppm of chloride was encountered at a depth of 104 feet below
the land surface. The well was immediately "pulled back"
20 feet, to a depth of 84 feet, where the chloride content of
the water was only 19 ppm. A layer of fine sand between 84
and 104 feet apparently acts as a confining bed, because no

FLORIDA GEOLOGICAL SURVEY

Figure 9. Map of the Stuart area showing the chloride con-
tent of water from wells.

INFORMATION CIRCULAR NO. 12

Table 3. Chloride Concentration in Water
Samples from Selected Wells

Depth of well, Chloride
in feet, below content
Well No. land surface Date (ppm)

100 47 Sept. 20, 1946 110
Oct. 7, 1946 131
Dec. 19, 1946 138
Feb. 6, 1947 124
Mar. 13, 1947 153
Apr. 24, 1947 118
May 12, 1947 104
June 25, 1947 111
Mar. 10, 1948 104
June 10, 1948 89
Sept. 15, 1948 94
Dec. 10, 1948 74
Feb. 11, 1949 110
July 1, 1949 113
Apr. 27, 1952 185
Jan. 28, 1955 161
May 11, 1955 166
June 29, 1955 148

105 88 Aug. 13, 1946 34
Sept. 20, 1946 27
Nov. 7, 1946 41
Dec. 19, 1946 67
Feb. 6, 1947 53
Mar. 13, 1947 46
June 25, 1947 49
Mar. 10, 1948 37
June 10, 1948 61
Sept. 15, 1948 37
Dec. 10, 1948 27
Feb. 11, 1949 63
Apr. 7, 1950 188
Jan. 18, 1951 102
Aug. 21, 1951 109
Mar. 27, 1952 167

FLORIDA GEOLOGICAL SURVEY

Table 3. Chloride Concentration in Water
Samples from Selected Wells (continued)

Depth of well, Chloride
in feet, below content
Well No. land surface Date (ppm)
353 80 July 28, 1953 545
Jan. 20, 1955 670
June 30, 1955 580
Aug. 16, 1955 680

362 23 Aug. 4, 1953 35
Jan. 21, 1955 615
June 30, 1955 1,370
Aug. 16, 1955 2,020
Sept. 8, 1955 1,980

515 60 Oct. 6, 1953 106
Jan. 11, 1955 131
Apr. 20, 1955 123
June 29, 1955 121
Sept. 5, 1955 157
Oct. 5, 1955 117

518 57 Oct. 6, 1953 46
Jan. 10, 1955 160
Jan. 27, 1955 103
Apr. 20, 1955 87
May 11, 1955 80
June 29, 1955 96
Aug. 16, 1955 132
Sept. 7, 1955 136

520 35 Oct. 6, 1953 64
Jan. 10, 1955 66
Apr. 20, 1955 75
June 29, 1955 83
Sept. 7, 1955 79

523 45 Oct. 6, 1953 53
Jan. 10, 1955 36
Apr. 20, 1955 33
June 10, 1955 32
Sept. 7, 1955 36

FLORIDA GEOLOGICAL SURVEY

Whenthe data from the tests in the city well fields were
analyzed by the Theis method, the computed values of the
coefficient of transmissibility ranged from 18, 000 to 170, 000
gpd per foot for the same area, indicating that the aquifer
does not meet all the above conditions. The main producing
zone, which is between 103 and 140 feet (see well log) in the
new well field, is reasonably homogeneous, isotropic, and
uniform in thickness, judging from well logs and cuttings
and the performance of individual wells. For a test of short
duration the aquifer is, in effect, of infinite areal extent,
but it is not bounded above by an impermeable bed, as is
shown by the fact that the water level in shallow well 658A
(fig. 2) began to decline eight minutes after well 657 began
pumping (fig. 8). Also, the water was discharged on the
ground in the vicinity of the pumpedwells and, consequently,
the aquifer was receiving recharge. In addition, the aquifer
was not fully penetrated by the pumped wells. After correc-
tions were made for the effects of partial penetration and
also for the natural decline of the water table thatwas taking
place the data were further analyzed by means of the leaky-
aquifer method of Hantush and Jacob (1955, p. 95-100) and
a leaky-aquifer type curve developed by H.H. Cooper, Jr.,
of the U. S. Geological Survey, Tallahassee, Florida, (per-
sonal communication). This analysis produced values for
the coefficient of transmissibility ranging from 15,000 to
25, 000 gpd per foot, with a probable average near 20, 000
gpd per foot. This seems to be a reasonable coefficient of
transmissibilityfor the main producing zone of the aquifer.
When considering long-term pumping, vertical leakage from
the overlying beds is an important factor, and the coefficient
of transmissibility of the overlying beds should be added to
that of the main producing zone to obtain a realistic coefficient
of transmissibility for the well field.

SALINITY STUDIES

The chloride content of ground water is generally a
reliable index of the extent of contamination by salt water
from the sea or other sources. Water samples were collected
from severalhundred wells in the Stuart area for chloride
analysis (fig. 9). Those wells yieldingwater having anappre-
ciable chloride content were sampled periodically to detect
any variations in the chloride content of the water (table 3).

INFORMATION CIRCULAR NO. 12

Table 3. Chloride Concentration in Water
Samples from Selected Wells (continued)

Depth of well, Chloride
in feet, below content
Well No. land surface Date (ppm)

525

Oct. 6, 1953
Jan. 10, 1955
Apr. 20, 1955
Sept. 7, 1955

Oct. 22, 1953
Jan. 10, 1955
Apr. 20, 1955
June 29, 1955

Oct. 22, 1953
Jan. 10, 1955
Apr. 20, 1955
June 29, 1955

Nov. 9, 1953
Jan. 10, 1955
Apr. 20, 1955
June 29, 1955

Nov. 23, 1953
Jan. 10, 1955
Apr. 20, 1955
June 29, 1955

Apr. 15, 1955
June 29, 1955
Aug. 16, 1955
Sept. 7, 1955
Oct. 7, 1955

May 11, 1955
June 29, 1955
Aug. 16, 1955
Sept. 7, 1955

91
85
95
124

265
328
258
400

45
67
67
70

40
36
39
29

100
88
87
80

550
700
650
645
650

42
43
49
47

588

590

20

15

597

608

619

620

57

56

32 FLORIDA GEOLOGICAL- SURVEY

Table 3. Chloride Concentration in Water
Samples from Selected Wells (continued)

Depth of well, Chloride
in feet, below content
Well No. land surface Date (ppm)

Apr. 20, 1955
May 11, 1955
June 29, 1955
Aug. 16, 1955
Sept. 7, 1955

Jan. 11,
Apr. 29,
June 30,

Apr. 20,
June 29,
Aug. 16,

Apr. 20,
June 29,
Aug. 16,

Apr. 15,
June 29,
Sept. 7,

1955
1955
1955

1955
1955
1955

1955
1955
1955

1955
1955
1955

Feb. 3, 1955
Apr. 20, 1955
June 29, 1955
Sept. 7, 1955
Oct. 5, 1955

Apr. 19, 1955
June 29, 1955
Aug. 16, 1955

Apr. 22, 1955
Apr. 23, 1955
May 11, 1955
May 23, 1955

622

637

638

642

45

'647

113

654

20
16
18
15
43?

:245
48
32

230
272
352

56
76
65

98
40
34

197
312
348
348
280

775
780
810

9,180
19
14
15

63

687

720

60

104 '
84'

INFORMATION CIRCULAR NO. 12

Table 3. Chloride Concentration in Water
Samples from Selected Wells (continued)

Depth of well, Chloride
in feet, below content
Well No. land surface Date (ppm)

720 (continued) June 29,
Aug. 16,
Sept. 7,

722 112 Apr. 20,
May 26,
June 29,
Sept. 7,

1955
1955
1955

1955
1955
1955
1955

June 30, 1955
Aug. 16, 1955
Sept. 8, 1955
Oct. 7, 1955

June 30, 1955
Sept. 8, 1955
Oct. 7, 1955
Nov. 2, 1955

30
15
15

78
61
37
27

176
940
930
1,430

34
94
185
307

734

735

FLORIDA GEOLOGICAL SURVEY

appreciable increase in the chloride content occurred after
several months of intermittent pumping to irrigate a lawn.
It is believed that the salinity of the water in well 720 is the
result of direct encroachment from the St. Lucie River,
caused by the reduction of head induced by heavy pumping
in the water plant and ball park well fields. However, when
well 622, in the cityball park well field, was deepened from
56 feet to 115 feet the chloride content of the water decreased
slightly, from 36 ppm to 20 ppm, indicating that encroach-
ment had not reached the vicinity of the well field at the ball
park. The water in well 722, 600 feet east of the city water
plant and 600 feet from the river, contained 78 ppm of chlo-
ride at a depth of 112 feet below the land surface, indicating
that encroachment of water of high chloride content had not
reached the vicinity of the well field at the water plant. The
salt front is probably now stationary or is being pushed back
toward the river because of the increase of fresh-water head
following the cessation of pumping of the city water plant and
ball park well fields. The position of the salt front cannot
be determined accurately because of the lack of deep obser-
vation wells.

Some salt-water encroachment is occurring along the
eastern side of the peninsula in areas immediately adjacent
to the St. Lucie River and the Manatee Pocket. A relatively
high, discontinuous ridge parallels the eastern shoreline.
It is flanked on the west by low, swampy land. Streams and
ditches draining the lowland flow parallel to the ridge until
they reach gaps in the ridge where they discharge into the
salt water of the river. They reduce the fresh-water head
under the ridge during the dry season, so that even moderate
pumping in some areas results in movement of salt water
into the aquifer. The chloride content of the water inwell 362,
in this area(fig. 2), increased from 35 ppm in 1953 to more
than 2, 000 ppm in 1955 (table 3). This locality is especially
vulnerable to contamination because of its proximity to a
drainage canal.

Contamination from Artesian Aquifer

The beds of relatively impermeable clay and fine sand
of the Hawthorn formation act as an effective barrier to the

INFORMATION CIRCULAR NO. 12

vertical migration of salt water from the. artesian aquifer,
except where wells have punctured them. In the Stuart area,
the artesian water contains between 800 and 4, 500 ppm of
chloride and is under a pressure head of about40 feet above
the land surface. If this water were allowed to flow freely
at the surface it could contaminate the fresh water in the
shallow aquifer. The artesian water is highly corrosive,
and, after a period of years, may corrodethe casings of the
wells and create perforations through which the salty water
could escape into the fresh-water aquifer eventhough thetop
of the well is tightly capped. An electric log made by the
Florida Geological Survey of well 128, an artesian wellwith-
in 300 feet of the city water plant well field, indicated that
there were probably many breaks in the casing at various
intervals below the land surface. Saltwater escaping through
holes in the casing of this well is believed to be the probable
source of chloride contamination in the old city well field.
This conclusionwas reached when it became evident that the
contamination could not be direct encroachment from the
river because wells of the same depth as the city wells and
situated a few hundred feet from the river bank, directly
between the well field and the river, yielded water whose
chloride content was lower than that in the city.wells.

Evidence to support this conclusion was noted after the
water plant and ball park well fields were shut down. The
water in certain wells in the area increased markedly in
chloride content. When the data were plotted on a map, the
wells in which an increase in chloride content had occurred
formed a fan-shaped pattern extending downgradient from
the artesian well, the axis of the pattern closely paralleling
the direction of ground-water flow. The water in well 619,
nearest the artesian well, had the greatest increase in chlo-
ride content, whereas that in wells farther away showed a
smaller increase. Water in wells outside the area did not
change appreciably. It is believed the observed changes in
chloride concentrationwere causedby leakage of salty water
from the artesian well. Prior to the shutting down of the
water plant well field, most of the salty artesian water was
being drawn into the city supply wells, where it was diluted
by fresh water from within the area affected by pumping.

Well 128 was filled with cement on April 25, 1955, the
day that pumping ceased in the water plant well field, and

FLORIDA GEOLOGICAL SURVEY

the salty water in the aquifer.after. that time was artesian
water which had not been flushed away. The residual arte-
sian water, therefore, moved downgradient and was diluted
by fresh water as it progressed. As the salty water was
dispersed, the water from wells downgradient from the arte-
sian well became fresher.

SUMMARY AND CONCLUSIONS

All supplies of fresh ground water in the Stuart area are
obtained from the shallow nonartesian aquifer. The deep
(Floridan) artesian aquifer will yield large quantities of water
to flowing wells, but the water is too highly mineralized for
most purposes. The nonartesian aquifer, although it differs
from area to area, is composed generally of Pleistocene,
Pliocene andpossiblyMiocene deposits consisting of sand to
a depth of about 40 feet and alternating layers of limestone
or shell and sand from 40 feet to about 130 feet. Below
130 feet little or no water is available from the sands and
clays that form the major part of the Hawthorn formation,
the confining unit of the Floridan aquifer. The Floridan
aquifer is composed of limestones of the Vicksburg group,
the Ocala group, the Avon Park limestone, and the Lake
City limestone.

Pumping tests reveal that the new city well field is far
enough from the St. Lucie River that salt-water encroach-
ment should not be a problem if hydrologic conditions remain
substantially as they are at the present time.

So far, salt water has encroached in the Stuart area
only in a relatively narrow area adjacent to the St. Lucie
River and in areas near leaking artesian wells. Water-
table contour maps indicate that the fresh-water head is
sufficient to prevent extensive encroachment of salt water
into the shallow aquifer. If drainage canals are dug to depths
below sea level in the vicinity of the well field, however,
they could become avenues through which salt water may
encroach during periods of low ground-water levelsand high
tides. Also, drainage canals may lower the water table
sufficiently to allow salt water to encroach at depth in the
aquifer.

INFORMATION CIRCULAR NO. 12

The increase in the chloride content of the old city wells
was due largely to leaks in the casing of an artesian well in
the vicinity; however, water of high chloride content discov-
ered in a well about halfway between the old well field and
the St. Lucie River indicated that salt-water encroachment
from the direction of the river was occurring at depth inthe
aquifer. With a steady increase in pumping this encroach-
ment might eventually have reached the old well field, but
with the cessation of pumping in the old well field the salt
front should move back slowly toward the river. Moderate
pumping in the old well field could be resumed after the
aquifer around ithas been cleared of the salt-water contam-
ination.

Large additional water supplies can be developed in the
vicinity of the new well field, provided the wells are ade-
quately spaced and the pumping rates are not excessive.
Additionalwells a quarter of a mile or more south of the new
field would not seriously affect it. The wells would be in
areas where the altitude of the water table is relatively high
throughout the year, so there would be little danger of salt-
water encroachment due to pumping.

A continuous record of the fluctuation of the water level,
such as that obtained from the gage at well 147, provides a
record of the changes in ground-water storage inthe aquifer
throughout a given period. Determination of the chloride
content of samples collected periodically from selected ob-
servation wells will reveal any further movement of salt
water into the shallow aquifer.

Table 4, Records of Selected Wells

0, open hole; S, screen; P, standpoint.
Dom., domestic; Ind,, industrial; Irr., irrigation; Ob.,, observation; P.S., public supply.
Well located in Hanson Grant; township and range projected.

Well Depth Diameter Well fin.
No. Location Owner (ft.) (in.) ish (1) Use (2) Remqrks

NW SW: sec.4, T. 38 S., R.41 E.
NW SW; sec. 4, T. 38 S., R. 41 E.
NWi SWI sec.4, T. 38 S., R. 41 E.
SE, NE, sec. 5, T. 38 S., R.41 E.
NW SE* aec. 2, T. 38 S., R.41 E.
NW SWI sec.4, T.38 S., R.41 E.
NW` NWJ sec. 10, T. 38 S., R.41 E.
*SW NEn sec. 26, T. 38 S., R.41 E.
*SW SW sec. 7, T. 38 S., R.41 E.
*SWI SW sec. 27, T.38 S., Ri41 E.
*NE* NEI sec. 33, T. 38 S., R.41 E.
*NWf NW+ sec. 25, T. 38 S., R. 41 E.
*NW= NW sec. 25, T. 38 S., R.41 E.
*SE SW) sec. 18, T. 38 S., R.42 E.
*SE, SE sec. 24, T.38 S., R.41 E.
*SEJ SE. sec. 24, T. 38 S., R. 41 E.
*SW* SWI sec. 19, T. 38 S., R. 42 E.
NW* SEj sec. 25, T. 38 S., R.41 E.
*SE4 NEf sec. 25, T. 38 S., R.41 E.
*NWJ NEf sec. 25, T.38 S., R.41 E.
*SW S SE4 sec. 24, T.38 S., R.41 E.
*NW4 NEi sec. 24, T. 38 S., R.41 E.
*NW NE sec. 24, T. 38 S., R. 41 E.
*SE SWJ sec. 13, T.38 S., R.41 E.
*SW} SEf sec. 13, T. 38 S., R.41 E.
*NW+ SWJ sec. 13, T. 38 S., R.41 E.

City of Stuart
City of Stuart
City of Stuart
P. Pence
A.M. Bauer
City of Stuart
U.S. Geological Survey
C.E. Beedle
R. Darling
E. D. Johnson
L. 0. Fosky
D.H. Harvey
M. Whittle
C.H. Williams
P. Mispel
C. Pope
D. Steenken
M. Marshal
R.F. Saunderson
J. F. Gaughan
A. Irwin
C. Stiller
H. Stiller
E. Csapo
J. E. Friday
H.L. Gerould

P.S.
P.S.
P.S.
Ind.
Irr,
P.S.
Obs.
Dom.
Dom.
Dom.
Dom.
Dom.
Dom.
Dom.
Dom.
Dom.
Dom.
Dom.
Dom.
Dom.
Dom.
Dom.
Dom.
Dom.
Irr.
SDorm

See table 3.
Do.
Plugged.
Recorder; see fig. 7.

97
98
99
100
105
128
147
295
297
302
303
308
309
313
314
315
316
320
321
322
324
325
326
327
328
329

Table 4. Records of Selected Wells (continued)

Location

Depth
(ft.)

Owner

Well
No.

330
331
332
333
334
337
338
33,9
340
341
342
344
345
346
347
349
351
352
353
354
355
358
359
360
361
362
363
365
366
368

Diameter Well fin-
(in.) ish (1) Use (2)

*SEj SEi sec. 14, T.38 S., R.41 E.
*SWE SE sec. 14, T. 38 S., R. 41 E.
*SE1 NEI sec. 23, T.38 S., R.41 E.
*SE NWI sec. 23, T.38.S., R.41 E.
*SE. SWl sec. 14, T. 38 S., R.41 E.
*NW NEI sec. 26, T.38 S., R.41 E.
*SW1 NW* sec. 23, T.38 S., R.41 E.
*SEI SEJ sec. 15, T.38 S., R.41 E.
*SW SE sec. 15, T. 38 S., R.41 E.
*SE* NW* sec. 15, T. 38 S., R.41 E.
NE NWI sec. 15, T.38 S., R.41 E.
NEI SEJ sec. 9, T. 38 S., R. 41 E.
NW* SE sec. 9, T. 38 S., R. 41 E.
SEI NWI sec. 9, T.38 S., R.41 E.
*SW1 NWi sec. 14, T. 38 S., R. 41 E.
*NE SWt sec.14, T.38 S., R.41 E.
*SW NEi sec. 14, T. 38 S., R.41 E.
*NEI NE sec. 14, T. 38 S., R.41 E.
*SE* NE sec. 14, T.38 S. R.41 E.
*SE NWk sec. 13, T. 38 S., R. 41 E.
*NE SW; sec. 13, T. 38 S., R.41 E.
*NEI SEu sec.11, T.38 S., R.41 E.
NE SEI sec. 11, T.38 S., R.41 E.
SW -NE sec. 11, T.38 S, R.41 E.
NW NE sec. 11, T.38 S. R.41 E.
SWiSEf sec. 2, T.38 S., R.41 E.
. SW* SE* sec. 2, T. 38 S., R.41 E.
SW* SE* sec. 2, T. 38 S., R.41 E.
NW* SE sec. 2, T.38 S., R.41 E.
INW1 NW* sec. 2, T.38 S.,, R.41 E.

Remarks

A. Nelson
O. Mangil
C. M. Johnson
B.R. Sword
R. M. Powell
E.J. Florintine
C. Keck
P.W. Hickman'
P. W. Hickman
G.H. Cook
W.S. Walsh
R.L. Wall
R. L. Wall
H.W. Tressler
T.G. Schreckengast
R. Allison
T. B. Parish
S. Nekrassoff
S. Nekrassoff
W.F. Lawson
Unknown
Martin County Golf Club
C.T. Kemble
E. Svilokos
C.A. Lintell
C. Boxwell
H. Thelosen
E. B. Dugan'
W.E. Oliver
G. Sollitt .

Dom.
Dom.
Dom.
Dom.
Dom.
Dom.
Dom.
Dom.
Dom.
Dom.
Dom.
Dom.
Dom.
Dom.
Dom.
Dom.
Dom.
Dom.
Dom.
Dom.
Dom.
Dom.
Dom.
Dom.
Dom.
Dorm,
Dom.
Dom.
Dom.
Dom.

See table 3.

See table 3.

Table 4, Records of Selected Wells (continued)

Well Depth Diameter Well fin-
No. Location Owner (ft.) (in.) ish (1) Use (2) Remarks

371
372
375
376
380
381
383
385
386
387
388
394
399
404
405
406
469
471
474
475
476
478
479
481
482
486
487
488
492
493

NW* NW* sec, 2, T. 38 S., R, 41 E.
SW: NE seec. 3, T. 38 S. R. 41 E.
NW SW sec. 16, T.38S., R.41 E.
NE NEi sec. 17, T. 38 S., R. 41 E.
*NEI NW* sec. 32, T. 38 S., R. 41 E.
*SWL SEf sec. 29, T. 38 S., R.41 E.
*NEI SE sec, 29, T. 38 R. 41 E.
*NW NWI sec. 33, T. 38 S., R. 41 E.
*SEf SWJ see, 28, T. 38 S,, R.41 E.
*NWJ SEI sec. 21, T. 38 S., R. 41 E.
NW} SW) sec. 16, T. 38 S., R.41 E.
SW; SW sec 9, T. 38 S., R.41 E.
SW; SW sec. 9, T. 38 S., R. 41 E.
NE NE sec. 17, T. 38 S, R. 41 E.
NW SE; sec. 8, T. 38 S., R. 41 E.
NW; NEI sec. 17, T. 38 S. R. 41 E.
SW; NE sec. 3, T. 38 5., R. 41 E.
SW, NE sec. 3, T. 38 S., R.41 E.
SWj NE sec. 3, T. 38 S., R. 41 E.
NW NE sec. 3, T. 38 S., R. 41 E.
NW NE sec. 3, T. 38 S., R.41 E.
N NE sec. 3, T. 38 S., R. 41 E.
NW NEI sec. 3, T. 38 S., R. 41 E.
NW* NE sec. 3, T. 38 S., R. 41 E.
SWI NEI sec.3, T.38 S., R.41 E.
NE NWI sec. 3, T.38 S., R.41 E.
SE NW;* sec. 3, T. 38 S., R.41 E,
SE) NW sec. 3, T. 38 S., R.41 E.
SE; NW* sec. 3, T, 38 S., R.41 E.
SEI NW* sec. 3, T. 38 S., R. 41 E,

R.G. Ross
C. Allen
F. Blackstone
H. Clements
V. Brennan
C.A. Lees
. B. Beach
L.M. Johnson
C. Green
Quindly
C.L. Bruce
C. Luce
H.I. Burkey
F. E. Glass
D.E. Andrews
E.A. Wood
D.B. Irons
J. Menninger
R. L. Minnehan
A. O. Kanner
J. B. Frazier
D.F. Hudson
C.R, Ashley
D. H. Gleason
F. Stafford
Z. Mosley
H.M, Godfrey
C. Dunscombe
R.D. Hauk
E. Crary

91
21
65
55
52
38
40
68
15
* ?
52
80
20
50
90
79
18
50
16
80
55
88
22
100
63
30
22
16
63
80

2
1i
2
2
1)

2
2
1
2
1)

2
2
2
2
2
2
2
1F)

2
2
2

1*

12
1*
2
12
2
2

Dom,
Dom.
Dom.
Dom.
Dom,
Dom,
Dom.
Dom.
Dom.
Dom.
Dom.
Irr.
Irr.
Dom.
Dom.
Dom.
Irr.
Irr.
Irr.
Dom.
Irr.
Dom.
Irr.
Dom.
Irr.
Irr.
Irr.
Dom.
Dom.
Irr.

Flower farm.
Do.

Table 4. Records of Selected Wells (continued)

Well Depth Diameter Well fin-
No. Location Owner (ft.) (in.) ish (1) Use (2) Remarks

495
497
498
500
501
502
503
505
510
511
514
515
518
519
520
521
523
525
527
531
534
537
539
543
544
546
547
550
555
557
558

SW: NWf sec. 3, T.38 S., R. 41 E.
SW NW: sec. 3, T. 38 S., R.41 E.
SWJ NW a sec. 3, T. 38 S., R.41 E.
SW1 NW sec. 3, T. 38 S., R. 41 E.
SE* NE sec. 4, T. 38 S., R.41 E.
SE NEI sec. 4, T. 38 S., R.41 E.
SE NEI sec. 4, T.38 S., R.41 E.
SE NEI sec. 4, T. 38 S., R. 41 E.
SL NE sec. 4, T.38 S., R.41 E.
SE NW sec.4, T.38 S., R.41 E.
SE NWi sec.4, T.38 S., R.41 E.
SENW sec.4, T.38 S., R.41 E.
SW NW* sec.4, T.38 S., R.41 E.
SW NW* sec.4, T.38 S., R.41 E.
SW NW a sec. 4, T.38 S., R.41 E.
SW NW sec.4, T.38 S., R.41 E.
SW4NW a sec.4, T.38 S., R.41 E.
SW NWi sec.4, T. 38 S., R.41 E.
NW" SEf sec.3, T. 38 S., R. 41 E.
NW" SE* sec.3, T.38 S., R.41 E.
SW* SE* sec. 3, T.38 S., R. 41 E.
SW W SW* sec. 3, ,T. 38 S., R. 41 E.
NW* SW sec. 3, T. 38 S., R. 41 E.
SW* SW sec. 3, T. 38 S., R.41 E.
SW SW) sec.3, T.38 S., R.41 E.
SWj SWI sec, 3, T.38 S., R.41 E.
NW* NW sec. 10, T.38 S., R.41 E.
NE SEi sec.4, T. 38 S., R.41 E.
NEI SE* sec.4, T.38 S., R. 41 E.
NWi SE sec.4, T.38 S., R. 41 E.
NW* SEJ sec.4, T.38 S., R.41 E.

S. Peabody
R. Risavy
S.G. Burt
E.V. Lawrence
H.D. Stone
B.J. Fox
B.J. Fox
J.M. Speiner
W. Schumann
I. T. Rembert
H. W. Bessey
R. C. Johns
W. King
E. Cabre
H. W. Partlow
H.W. Partlow
A. Cepec
E. Tyner
E.J. Brasgalle
A. T. Compton
K. Krueger
A. Cleveland
F. O. Button
F. Sutton
D.S. Richardson
A. Espenna
J.W. Pegram
R.S. Hill
R. Hartman, Jr.
R.W. Hartman, Sr.
W.W. Meggett

Irr.
Irr.
Irr.
Irr.
Irr.
Dom.
Irr.
Dom.
Irr.
Irr.
Irr.
Irr.
Irr.
Irr.
Dom.
Irr.
Irr.
Irr.
Dom.
Irr.
Dom.
Dom.
Dom.
Dorn.
Dom.
Dom.
Dom.
Dom.
Irr.
Irr.
Irr.

Citrus grove.

See table 3.
Do.

See table 3.

See table 3.
Do.

O
0

C1

z

N

Table 4, Records of Selected Wells (continued)

Well Depth Diameter Well fin-
No, Location Owner (ft.) (in.) ish (1) Use (2) Remarks

560
563
565
566
571
573
575
576
577
578
580
583
584
585
587
588
590
591
594
595
597
598
605
606
608
611
612
613
614
617
618

H. G, Kindred 30 ? P Dom,

NEI NEI sec. 9, T. 38 S., R, 41 E.
SE) NEi sec. 9, T. 38 S., R. 41 E.
NEI NEI sec. 9, T. 38 S., R. 41 E.
NW' NWI sec. 10, T. 38 S., R.41 E.
NWI NEI sec. 9, T. 38 S., R. 41 E.
SWI SEI sec. 4, T. 38 5., R. 41 E.
SEI NEa sec.8, T. 38 S., R.41 E.
SW NEI sec. 8, T.38 S., R.41 E.
SEN NE sec. 8, T. 38 S., R. 41 E.
SE'NE sec. 8, T. 38 S., R. 41 E.
SW+ NEF sec. 8, T. 38 S., R. 41 E.
NE NZf sec. 8, T. 38 S., R. 41 E.
NW* NEsec. 8, T. 38 S., R. 41 E.
NW NE, sec. 8, T. 38 S., R. 41 E.
NE* NE sec. 8, T. 38 S., R. 41 E.
NW* NE) sec,8, T. 38 S., R.41 E.
SW* SE) sec. 5, T. 38 S., R. 41 E.
NW NEI -sec. 8, T. 38 S., R. 41 E.
SW SE sec. 5, T. 38 S., R. 41 E.
SW; S sec. 5, T. 38 S., R.41 E.
SW SEsec.5, T. 38 S., R. 41 E.
NW SE sec. 5, T. 38 S., R. 41 E.
SW NE- sec. 5, T. 38 S., R. 41 E.
SW: NE: sec.5, T.38 S., R.41'E.
NEI SE sec. 5, T.38 S., R. 41 E.
NEj SE* sec. 5, T. 38 S., R. 41 E.
NW* SWI sec. 4, T. 38 S., R. 41 E.
SEI SWI sec.4,T. 38 S., R.41 E.
SE* SEe sec. 5, T.38 S., R.41 E.
*NW1 NE* sec. 14, T. 38 S., R.41 E.
*NW* NW* sec. 13, T. 38 S., R. 41 E.

W. L. Sullivan
H.G. Harper
D. Giesbright
E. McGee
F. Thompson
L. D. Burchard
G. Zarnits
R. V. Johnson
H. Whalen
W.F. May
J.O. Powell
G.F. Barber
P.B. Caster
I. Taylor
E.F. Bulla
K.S. Stimmell
R.H. Schwarz
J. R. Pomeroy
G. Schlesier
A.H. Chappelka
F. Schwarz
C.M. Fogt
H. Harper
D. L. Williams
D. W. Anderson
R. Garner
B. Holmes
C.H. Hardwick
C. G. Bischoff
J. Kuhn

li
2
2
1;
1

14
1*
1
1"
1
2
2
?4
2

1*
2

2
481
2
21
2
2

2

Irr.
Irr.
Dom.
Dom.
Dom.
Dorn.
Dom.
Irr.
Dom.
Dom.
Dorm.
Dom.
Dom.
Irr.
Dom.
Irr.
Dom.
Irr.
Irr.
Irr.
Irr.
Irr.
Irr.
Irr.
Irr.
Irr.
Dom.
Dom.
Dom.
Dom.

Flower farm.

See table 3.
Do.

See table 3.

See table 3.

0
tr

0

0

C-I

<

.cr<

Table 4. Records of Selected Wells (continued)

Well Depth Diameter Well fin-
No. Location Owner (ft.) (in.) ish (1) Use (2) Remarks

619 NWi SWI sec.4, T.38 S., R.41 E.
620 NE% SWI sec.4, T.38 S., R.41 E.
621 NE1 SWX sec.4, T.38 S., R.41 E.
622 NEt SW see,4, T.38 S., R.41 E.
623 NE SW sec.4, T.38 S., R.41 E.
627 SWf NE, sec. 9, T.38 S., R.41 E.
629 SW' SW sec.9, T.38 S., R.41 E.
631 NW1 NE sec. 9, T.38 S., R.41 E.
637 NW SE* sec.4, T.38 S., R.41 E.
638 SW NW* sec. 4, T.38 S., R. 41 E.
639 SE SE sec.4, T.38 S., R.41 E.
642 S NEt sec.5, T.38 S., R.41 E.
643 NW NWf sec. 13, T. 38 S., R.41 E.
647 NE SW sec.4, T,38 S., R.41 E.
653 'SW SW4.eec. 10, T.38 S., R.41 E.
654 NW SW sec.4, T.38 S., R.41 E.
655 NE NW sec. 9, T.38 S., R.41 E.
656 NW.NE sec.9, T.38S., R.41 E.
657 NW NE sec.9, T.38 S., R.41 E.
658 NW NE sec, 9, T.38 S., R.41 E.
658A NW NE sec. 9, T. 38 S., R.41 E.
659 NW NE ec. 9, T. 38 S., R.41 E.
660 SE NE* sec.5, T.38 S., R.41 E.
666 SE NE sec. 5, T.38 S., R.41 E.'
674 NW SW* sec.9, T.38 S., R. 41 E.
687 NW* SEJ sec.5, T.38 S., R.41 E.
720 SW* NW sec. 4, T. 38 S., R.41 E.
721, SW NE uec.4, T.38 S., R.41 E.
722 NW SW sec.4, T.38 S., R.41 E.
723 NW NE sec.9, T.38 S., R.41 E.
724 NEt NEt sec.9, T.38 S., R.41 E.

City of Stuart
City of Stuart
City of Stuart
City of Stuart
City of Stuart
S. Smith
H.I. Burkey
Martin County Garage
R.W. Hartman, Sr.
E. Cabre
City of Stuart
St. Lucie Hotel
J. Kuhn
American Legion
G. Knouse
F. E. Rue
F. Rowell
City of Stuart
City of Stuart
City of Stuart
U.S. Geological Survey
City of Stuart
Casaboom
A. Dehone
C. Luce
Sheppard Park
E. Tyner
H.P. Hudson
City of Stuart
City of Stuart
City of Stuart

57
56
56
56
56
40
103
53
15
38
72
46
26
113
78
63
63
145
125
125
13
125
45
60
103
60
84
84
112
125
125

Obs.
Obs.
P.S.
Obs.
P.S.
Irr.
Irr.
Dom.
Irr.
Irr.
Fire
Irr.
Dom.
Irr.
Irr.
Irr.
Dom.
Obs.
P.S.
Obs.
Obe.
Obs.
Irr.
Irr.
Irr.
Irr.
Irr,
Irr.
Irr.
P.S.
P.S.

See table 3.
Do.

See table 3.

Flower farm.
Do.

See table 3.

Not in use. See table 3.

Not in use. See table 3.
Flower farm.
See table 3.

Recorder

Not in use.
Do.
Do.
See table 3.
Do.

See table 3.

Table 4, Records of Selected Wells (continued)

Well Depth Diameter Well fin-
No. Location Owner (ft.) (in,) ish (1) Use (2) Remarks

NEI SW sec, 4, T. 38 S., R. 41 E.
*SE SW- sec. 12, T. 38 5., R. 41 E.
SW* NE eec.4, T, 38 S., R, 41 E.
*NE SW sec. 1, T. 38 S., R, 41 E.
*NEI SWI sec, 13, T.38 S., R.41 E.
*NW NE1 sec. 25, T. 38 S. R. 41 E.
*SWi SW) sec. 12, T. 38 S., R.41 E.
*NW SWi sec. 12, T. 38 S., R. 41 E.
*NW, NW seec. 13, T. 38 S., R, 41 E.
*NW NW sec. 13, T. 38 S., R. 41 E.

Martin County School
Dutton
Episcopal Church
Danforth
Metcalf
J.J. O'Connor
Andrew Berkey
J. Whiticar
J. Whiticar
J. Whiticar

731
732
733
734
735
738
753
755
766
767

P.S.
Irr,
Irr.
Dom.
Dom.
Dom,
Test
Irr.
Irr.
Irr.

See table 3.
Do.

FLORIDA GEOLOGICAL SURVEY

the salty water in the aquifer.after. that time was artesian
water which had not been flushed away. The residual arte-
sian water, therefore, moved downgradient and was diluted
by fresh water as it progressed. As the salty water was
dispersed, the water from wells downgradient from the arte-
sian well became fresher.

SUMMARY AND CONCLUSIONS

All supplies of fresh ground water in the Stuart area are
obtained from the shallow nonartesian aquifer. The deep
(Floridan) artesian aquifer will yield large quantities of water
to flowing wells, but the water is too highly mineralized for
most purposes. The nonartesian aquifer, although it differs
from area to area, is composed generally of Pleistocene,
Pliocene andpossiblyMiocene deposits consisting of sand to
a depth of about 40 feet and alternating layers of limestone
or shell and sand from 40 feet to about 130 feet. Below
130 feet little or no water is available from the sands and
clays that form the major part of the Hawthorn formation,
the confining unit of the Floridan aquifer. The Floridan
aquifer is composed of limestones of the Vicksburg group,
the Ocala group, the Avon Park limestone, and the Lake
City limestone.

Pumping tests reveal that the new city well field is far
enough from the St. Lucie River that salt-water encroach-
ment should not be a problem if hydrologic conditions remain
substantially as they are at the present time.

So far, salt water has encroached in the Stuart area
only in a relatively narrow area adjacent to the St. Lucie
River and in areas near leaking artesian wells. Water-
table contour maps indicate that the fresh-water head is
sufficient to prevent extensive encroachment of salt water
into the shallow aquifer. If drainage canals are dug to depths
below sea level in the vicinity of the well field, however,
they could become avenues through which salt water may
encroach during periods of low ground-water levelsand high
tides. Also, drainage canals may lower the water table
sufficiently to allow salt water to encroach at depth in the
aquifer.

INFORMATION CIRCULAR NO. 12

REFERENCES

Black, A. P.
1951

(and Brown, Eugene) Chemical character of
Florida's waters: Florida State Board Cons. ,
Div. Water Survey and Research, Paper 6,
p. 13, 79.

1953 (and Brown, Eugene, and Pearce, J.M.) Salt
water intrusion in Florida: Florida State
Board Cons. Div. Water Survey and Research,
Paper 9, p. 2, 5.

Brown, Eugene (see Black)

Collins, W.D.
1928 (and Howard, C. S.) Chemical character of
waters of Florida: U.S. Geol. Survey Water-
Supply Paper 596-G, p. 193-195, 220-221.

Cooke, C. Wythe (see also Parker)
1945 Geology of Florida: Florida Geol. Survey
Bull. 29, p. 223-269.

Ferguson, G. E. (see Parker)

Hantush, M. S.
1955 (and Jacob, C. E.) Non-steady radial flow in
an infinite leaky aquifer: Am. Geophys. Union
Trans., vol. 36, no. 1, p. 95-100.

Howard, C.S. (see Collins)

Jacob, C.E. (see Hantush)

Love, S.K. (see Parker)

Mansfield, W. C.
1939 Notes on the upper Tertiary and Pleistocene
mollusks of peninsular Florida: Florida Geol.
Survey Bull. 18, p. 29-34.

FLORIDA GEOLOGICAL SURVEY

Matson, G. C.
1913 (and Sanford, Samuel) Geology and ground
waters of Florida: U.S. Geol. Survey Water-
Supply Paper 319, p. 381-384.

Parker, G.G.
1944 (and Cooke, C. Wythe) Late Cenozoic geology
of southern Florida, with a discussion of the
ground water: Florida Geol. Survey Bull. 27,
p. 41.

1955 (and Ferguson, G. E. Love, S. K. and others)
Water resources of southeastern Florida, with
special reference to the geology and ground
water of the Miami area: U.S. Geol. Survey
Water-Supply Paper 1255, p. 174-175, 814-
815.

Pearce, J. M. (see Black, 1953)

Sanford, Samuel (see Matson)

Stringfield, V. T.
1936 Artesian water in the Florida peninsula: U.S.
Geol. SurveyWater-SupplyPaper 773-C, p. 170,
183, 193.

Theis, C.V.
1935 The relation between the lowering of the piezo-
metric surface and the rate and duration of
discharge of a well using ground-water storage:
Am. Geophys. Union Trans., p. 519-524.

1938 The significance and nature of the cone of de-
pression in ground water bodies: Econ. Geol-
ogy, vol. 33, no. 8, p. 892, 894.

U. S. Geological Survey
Water levels and artesian pressures in obser-
vation wells in the United States; 1950, 1951,
1952, part 2, Southeastern States: Water -Supply
Papers 1166, p. 80-81, 1192, p. 65, and 1222,
p. 77, respectively.

INFORMATION CIRCULAR NO. 12

Wenzel, L.K.
1942 Methods for determining permeability of water-
bearing materials, with special reference to
discharging-well methods: U.S. Geol. Survey
Water-Supply Paper 887, p. 87-90.

FLRD GEOLOSk ( IC SUfRiW

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	Title Page
	Table of Contents
	Abstract
	Introduction
	Location and general features
	Geologic formations and their water-bearing...
	Ground water
	Quantitative studies
	Salinity studies
	Summary and conclusions
	References