CO

APPRAISAL OF UNCONTROLLED FLOWING

ARTESIAN WELLS IN FLORIDA

A L A B A

G I A

2
ot
O U.S. GEOLOGICAL SURVEY

Water-Resources Investigations 78

O
ot

8
D Prepared in cooperation with the
FLORIDA DEPARTMENT OF ENVIRONMENTAL REGULATION
BUREAU OF WATER RESOURCES MANAGEMENT
i
a.
BIBLIOGRAPHIC DATA 1. Report No. 3. Recipient's Accession No.
SHEET
4. Title and Subtitle 5. Report Date
December 1978
APPRAISAL OF UNCONTROLLED FLOWING ARTESIAN 6.
WELLS IN FLORIDA
7. Author(s) 8. Performing Organization Rept.
Henry G. Healy No 'USGS/WRI 78-95
9. Performing Organization Name and Address 10. Project/Task/Work Unit No.
U.S. Geological Survey, Water Resources Division
Suite F-240 11. Contract/Grant No.

325 John Knox Road

Florida 32303
12. Sponso r »ng Organization Name and Address 13. Type of Report & Period
U.S. Geological Survey, Water Resources Division Covered
Suite F-240
325 John Knox Road 14.
Tallahassee, Florida 32303
15. Supplementary Notes

16. Abstracts

An estimated 15,000 uncontrolled flowing wells statewide are wastefully

discharging about 790 million gallons per day by surface and internal flow.
Seventy percent of the discharge, 550 million gallons per day, is from uncon-
trolled flowing wells in 14 counties in east-coastal and southwest parts of
the State. Programs for the control of flowing wells are being carried on
by state, county, municipal, or federal agencies in 21 counties.

17. Key Words and Document Analysis. 17a. Descriptors

Aquifers, artesian wells, subsurface flow, saltwater intrusion

I7b. Identifiers/Open-Ended Terms

Florida, Floridan aquifer, unconfined aquifers

I7e. COSATI Field/Group

18. Availability Statement 19. Security Class (This 21. "No. of Pages
Report)
UNCLASSIFIED. 26
No restriction on distribuiton. 20. Security Class (This 22. Price
Page
UNCLASSIFIED
ro«M NTI»-M <KEV. 10-73) ENDORSED BY ANSI AND UNESCO. THIS FORM MAY BE REPRODUCED USCOMM-OC 82C9-P74
APPRAISAL OF UNCONTROLLED FLOWING

ARTESIAN WELLS IN FLORIDA

By Henry G. Healy

U.S. GEOLOGICAL SURVEY

Water-Resources Investigations 78-95

Prepared in cooperation with the

FLORIDA DEPARTMENT OF ENVIRONMENTAL REGULATION

BUREAU OF WATER RESOURCES MANAGEMENT

1978
 UNITED STATES DEPARTMENT OF THE INTERIOR

CECIL D. ANDRUS, Secretary

GEOLOGICAL SURVEY

H. William Menard, Director

For additional information write to:

U.S. Geological Survey

325 John Knox Road
Suite F-240
Tallahassee, Florida 32303
 CONTENTS
Page

Abstract ............................ 1
The flowing well problem .................... 2
Historical summary. .................... 2
Purpose and scope. ....................... 6
Factors influencing flow. ................. 7
Effects of uncontrolled flow. ............... 7
Areas of uncontrolled flowing wells. .............. 13
Density and distribution of wells ............. 13
Estimated number of wells ................. 13
Quantity of water discharged. ............... 16
Surface flow ..................... 16
Internal flow. .................... 17
Principal problem areas .................. 17
Methods of controlling flowing wells .............. 18
Program for controlling flowing wells. ............. 21
Summary. ............................ 24
References ........................... 25

ILLUSTRATIONS

Figure 1. Map showing areas of water supply from shallow

aquifers and the thickness of the zone of potable
water in the Floridan aquifer ........... 3
2. Map showing numbers of uncontrolled flowing artesian
wells ....................... 5
3. Schematic diagrams showing: A) Relation between salt-
water and freshwater illustrating the Ghyben-Herzberg
principle, and B) its effect in an artesian aquifer
where potentiometric surface has declined ..... 9
4. Schematic diagram illustrating migration of poor
quality water by upward leakage through corroded
casings or improperly constructed wells ...... 10
5. Schematic diagram illustrating variations of internal
flow induced by pumping .............. 12
6. Map showing areas of artesian flow from the Floridan
aquifer, May 1974 ................. 14
7. Map showing principal problem areas of uncontrolled
flowing artesian wells. .............. 15

TABLES

Table 1. Summary of pertinent data on uncontrolled artesian

flow in principal problem areas in Florida by
counties. ..................... 19
2. Summary of current programs for the control of flowing
wells in Florida by counties. ........... 22

iii
 For use of those readers who may prefer to use metric units rather
than U.S. customary units; the conversion factors for the terms used
in this report are listed below:

Multiply U.S. customary unit By To obtain metric unit

inch (in.) 25.4 millimeter (mm)

foot (ft) .3048 meter (m)
gallons per minute (gal/min) .06309 liters per second (L/s)
square mile (mi^) 2.590 square kilometer (km^)
million gallons per day .04381 cubic meters per second
(Mgal/d) (m3/s)

IV
 APPRAISAL OF UNCONTROLLED FLOWING

ARTESIAN WELLS IN FLORIDA

By Henry G. Healy -

ABSTRACT

An estimated 15,000 uncontrolled flowing wells, many discharging

water of poor quality are wastefully discharging about 790 million
gallons per day by surface and internal flow. Internal flow in
principal problem areas in 14 counties is estimated at 550 million
gallons per day. Fourteen principal problem areas have been identified
in Brevard, Charlotte, Clay, De Soto, Duval, Flagler, Glades, Hendry,
Hillsborough, Lee, Manatee, Martin, Nassau, and Sarasota Counties.

In many areas, uncontrolled discharge over the years has caused a

decline in the potentiometric surface locally and regionally, and a
deterioration of the potable water aquifers. Programs for control of
flowing wells are being carried on by state, county, municipal, or
federal agencies in 21 counties.
 THE FLOWING WELL PROBLEM

In 1956 the Florida Water Resources Study Commission identified

"wasteful flow" from uncontrolled flowing artesian wells in 29 counties
as being one of three most important water problems in Florida. The
other two are saltwater encroachment (20 counties) and reduction of flow
from wells (28 counties) (Hendry and Lavender, 1959, p. 12).

Uncontrolled flowing artesian wells, improperly constructed and

maintained, contribute to waste by surface flow and, in many areas, are
the principal means of deterioration of freshwater by upward leakage of
saltwater into water-table aquifers, shallow artesian aquifers, and
upper zones of the Floridan aquifer used as sources of water supply.

Hendry and Lavender (1957, p. 19) define wildly flowing wells as,
"...those that have been abandoned and flowing, those used mainly for
irrigation and livestock which are permitted to flow continuously, and
those wells provided with valves which are now inoperative to some
degree, permitting leakage." In this report, an uncontrolled or free-
flowing well is an artesian well either without a mechanism for control-
ling discharge or a well that is allowed to flow continuously at the
land surface as well as those wells that only flow internally below land
surface through corroded or leaky casings or from improperly cased or
otherwise poorly constructed wells.

Shallow aquifers are becoming increasingly important as sources of

ground-water supply, particularly in those areas where water in the
Floridan aquifer system is highly mineralized or where freshwater zones
in the Floridan are relatively thin (fig. 1). In southwest Florida
in Collier, Charlotte, Lee, and Sarasota Counties pumpage from shallow
aquifers for municipal and industrial uses increased from 26 Mgal/d
in 1970 (Pride, 1973) to about 35 Mgal/d in 1975 (Leach, 1978). In east
and southeast coastal Florida in Brevard, Flagler, Indian River,
Martin, Palm Beach, St. Johns, and St. Lucie Counties shallow aquifer
pumpage increased from 24 Mgal/d in 1970 (Healy, 1972) to about 73
Mgal/d in 1975 (Healy, 1977). The increased use of ground water has
resulted in considerable stress to the shallow aquifers; consequently,
water levels have declined and some deterioration in the quality of
freshwater has occurred.

Historical Summary

A summary of the chronological history (1903-1955) of water-

conservation laws and acts that relate to ground water is presented by
Hendry and Lavender (1957, pp. 12-16). According to Hendry and Lavender
(1957, p. 14) the first legislative action specifically for regulation
and control of flow in wells in Sarasota, Manatee, and Seminole Counties
was enacted in 1953. A statewide inventory of flowing artesian wells
was promoted by the Florida Association of Soil Conservation District
Supervisors and the Florida Water Resources Study Commission in 1954-56
30*-

29*

EXPLANATION
28'

Shollow aquifer chief sources of supply

(Modified from Healy , 1977)

Thickness of zone of potoble water in the

Floridon aquifer less than 250ft. Chloride
or sulfate exceeds 250 mg/l .(Modified
27 from Cousey ond Leve, 1976.)

Biscoyne aquifer

26

0 C 20 30 40 30 MILES

85» 84' 83» 82* 80*

Figure 1. Areas of water supply from shallow aquifers and the thickness of the
zone of potable water in the Floridan aquifer.
(Hendry and Lavender, 1959, p. 12). In response to a request by the
state legislature, the then Florida Geological Survey located 1,883 wild
flowing wells in 44 counties during 1956-57 (Hendry and Lavender, 1959).
Several recent inventories of uncontrolled flowing artesian wells have
been made by the U.S. Geological Survey in local areas in cooperation
with water management districts and county and local programs for
investigating and reducing the number of uncontrolled flowing wells.
The numbers of uncontrolled flowing wells inventoried by the Florida
Geological Survey in 1956 and 1957 plus the estimated or inventoried
numbers of wells flowing internally and on the surface made by the U.S.
Geological Survey in 1977, are shown on figure 2.

In many areas, uncontrolled flowing artesian wells were recognized

and reported as a potential problem by early investigators of water
resources in Florida. The reports briefly discuss: (1) effects of
uncontrolled flowing wells in Manatee County (Peek, 1958; and Peek and
Anders, 1955); Hillsborough County (Peek, 1953); and (2) deterioration
of shallow aquifers by upward leakage and internal flow in Glades and
Hendry Counties (Klein and others, 1964), in Martin County (Lichtler,
1960), and in Lee County (Boggess and others, 1977).

During the period 1900 to early 1950's, thousands of wells were

drilled into the Floridan aquifer to obtain artesian (flowing) water for
irrigation and stock watering. Most of the wells were in coastal and
inland agricultural areas of low elevation where artesian flow from the
Floridan aquifer offered an easily procurable, relatively inexpensive,
and reliable source of water supply. The water, however, was saline in
some areas. Cooper and Stringfield (1950, p. 6), in discussing some
problems of development and conservation, state "...apparently the fact
that the artesian water is salty in some areas has not greatly limited
its use for irrigation. Hundreds of flowing wells that yield water too
salty for municipal and most industrial uses are being used for irriga-
tion along the east and west coasts. Many yield water having a chloride
content of more than 1,000 parts per million."

Well drilling practices in many areas include casing a well only

part of its entire depth. For example, a well drilled 600 to 800 feet
deep might contain only 80 ft of casing (Klein and others, 1964). The
length of casing depends upon economic factors as well as hydrologic and
geologic conditions at the well site. An uncased hole penetrating two
or more aquifers allows free circulation between the aquifers. Water in
the deeper aquifers generally is under higher pressure and more mineral-
ized than water in the more shallow aquifers. Thus deep and improperly
cased wells allowed upward migration and mixing of the mineralized water
with water in the more shallow aquifers, and consequently, contamination
and deterioration in the quality of water in the shallower aquifers. In
southwest Florida, particularly, in Manatee, Sarasota, Charlotte, and
Lee Counties, the use of black-iron casings was widespread. In time,
however, the casings deteriorated because of the corrosive effect of
high chloride and sulfate concentration of the ground water and began
leaking saltwater into shallow aquifers, which reduced the usefulness of
 < Tl3 ~!~ . ""77

i WAKULLA 1

. .__._. 5

GULF IFRANKLIN J

EXPLANATION

19 Reported continuously flowing wells,

Hendry and Lavender (1959)
70 Estimated or inventoried flowing wells,
U.S. Geological Survey. Includes internally
flowing wells (1977)
Wells not inventoried.

25* -

80'

Figure 2. Numbers of uncontrolled flowing artesian wells.

those aquifers as potential sources of water supply. In addition, con-
tamination of underlying aquifers has occurred by downward leakage of
saltwater through corroded casings of wells drilled in areas adjacent to
tidal water bodies in Lee County (Boggess and others, 1977) and in
Okaloosa County (Trapp and others, 1977).

In recent years, many areas formerly used for agriculture are being
converted to residential to accommodate the burgeoning population.
Wells in former agricultural areas were abandoned and no effort was made
to halt the uncontrolled flow from these wells. With development of
homesites and trailer parks, many of the abandoned wells were either
plugged at the surface or covered by construction. Also many wells that
formerly flowed at the surface ceased flowing when artesian pressures
declined because of increased local or regional pumping, or drought.
Many of those wells are hardly recognizable as wells today because of
the deterioration of the casing at the surface. The surface expressions
of many appear as seeps and springs rather than continuously discharging
wells.

An increased awareness of developing water problems during the

successive wet and dry periods of 1948-49 and 1950-52 resulted in enact-
ment of regulatory measures by the 1953 State Legislature (Chapter
370.051-370.055, Florida Statutes, 1953). These statutes required that
valves be installed on all flowing wells and that uncontrolled flowing
artesian wells be capped or plugged.

Failure to enforce the provisions of many of the early laws resulted

from: (1) The lack of knowledge or comprehension of the seriousness of
the problem; (2) the fact that each law had a restricted areal applica-
tion rather than being statewide in scope and application; and (3) the
"imbedding" of a potentially effective good law with a host of other
special laws which were neither approved nor appropriately funded
(Hendry and Lavender, 1957, p. 13).

PURPOSE AND SCOPE

Extensive and expanded use of ground water for municipal, indus-

trial, and agricultural supplies has resulted in the need for a thorough
and continuing assessment of ground-water resources in the State. The
problem of artesian wells flowing uncontrolled at and below land surface
is of importance to the conservation of the State's water supply. An
evaluation of problem areas will provide state regulatory agencies with
a sound basis for making management decisions necessary for the protec-
tion of shallow aquifers and to effectively reduce and otherwise control
water loss from uncontrolled flowing wells.

This report appraises the problem of flowing wells in Florida. It

presents a general statewide summary of uncontrolled flowing artesian
wells based on data available from reports and field data files. The
report emphasizes principal problem areas and includes the estimated
number of uncontrolled flowing wells and their impact, primarily on
contamination of shallow aquifers. This report is the result of cooper-
ative study with the Florida Department of Environmental Regulation to
obtain information on the importance and magnitude of the problem of
uncontrolled flowing wells and any existing programs of control.

Factors Influencing Flow

Control of flowing wells involves an understanding of the physical

factors influencing flow. The yield of a well by artesian flow is
controlled by many variables which may be divided into the general
categories of well construction and the geologic and hydrologic char-
acteristics of the aquifer.

The length of casing in relation to the total depth of the well is

important in controlling the quantity of water flowing at the well head
or internally. Sproul and others (1972, p. 10) reported that the
internal leakage within uncased parts of wells ranged from about 30 to
nearly 100 gal/min (gallons per minute) in the McGregor Isles area, Lee
County. The relation of this and other factors to flow have been
treated at length in reports of hydrologic and water-resources investi-
gations. Factors influencing well yields have been discussed in detail
by many authors, including Boggess (1974), Wilson (1977), and Lichtler
(1960),

Effects of Uncontrolled Flow

Uncontrolled artesian flow affects ground-water resources by:

lowering the potentiometric surfaces; decreasing volumes of flow; and
causing migration of saltwater into freshwater zones under certain
geologic and hydrologic conditions.

The potentiometric surface of the Floridan aquifer fluctuates

continuously in response to changes in the quantities of water recharged
to and discharged from the aquifer. The potentiometric surface rises
during wet periods and declines during dry periods. Hydrostatic or
hydrodynamic pressure of the water in the aquifer, represented by the
potentiometric surface or water level in the well, normally acts as a
pressure barrier to prevent highly mineralized water from migrating
into the freshwater aquifer. Thus, declines in water levels may signal
the eventual migration of saltwater into the freshwater part of the
Floridan aquifer, particularly in coastal areas, except where such
migration is prevented by impermeable beds.

Generally, under hydrostatic equilibrium, the depth of freshwater

below mean sea level is about 40 times the height of the potentiometric
surface above mean sea level, or, for each foot that the potentiometric
surface stands above mean sea level, the freshwater will extend an
additional 40 ft below sea level. Generally, a decline of one foot of
freshwater will result in an approximate rise of 40 ft of saltwater.
This relation between saltwater and freshwater, is the Ghyben-Herzberg
principle and provides the mechanism by which saltwater encroachment
takes place. The principle and its application has been described and
discussed in many reports of ground-water resource studies, including
Heath and Smith (1958), Lichtler (1960), McCoy (1962), and Peek (1959).
The principle has been modified to apply to the dynamic condition of
constant ground-water flow. The modifications, however, are usually
minor and the Ghyben-Herzberg ratio can be used to estimate the minimum
depth to saltwater in areas adjacent to and underlain by seawater (Heath
and Smith, 1958, and Lichtler, 1960).

Figure 3-A is a generalized cross section of Florida-illustrating

the relation between freshwater and saltwater. Figure 3-B shows the
upward migration of saltwater of about 40 ft (from 400 to 360 ft) in
response to 1-foot decline of the potentiometric surface in the artesian
aquifer. In figure 3-B the saltwater has migrated into the upper part
of the aquifer that previously contained only freshwater.

Some of the ways contamination by saltwater from wells occurs

through corroded casings, improperly constructed wells, and by pumping
conditions are illustrated by figures 4 and 5.

In many counties in southwest and east-coastal Florida, shallow

aquifers are the only sources of freshwater. In several locations these
aquifers are being contaminated by upward migration of highly mineral-
ized water from the underlying Floridan aquifer. Upward movement of
saltwater can occur in several ways as schematically illustrated in
figure 4 and.figure 5. The horizontal distance between wells in figures
4 and 5 is not significant. Each well represents an isolated example
showing different types of internal flow. The following descriptions
apply to figure 4.

Well A. Properly constructed flowing artesian well with valve that

taps the secondary artesian aquifer. No contamination occurring, but
could receive contamination if nearby wells such as well B exist.

Well B. Abandoned flowing artesian well with corroded casing in

the secondary artesian aquifer and open well bore to saltwater in the
top of the artesian aquifer. Saltwater is flowing up the open well bore
and through corroded casings and contaminating three freshwater aquifers:
the secondary artesian aquifer; the shallow artesian aquifer; and the
water-table aquifer. Surface flow is also contaminating the water-table
aquifer.

Well C. Abandoned flowing artesian well with an uncased well bore.

Saltwater from the deeper part of the artesian aquifer is flowing up the
open well bore and contaminating the three overlying freshwater aquifers.
Surface flow from this well is also contaminating the water-table aquifer
and adjacent surface-water bodies.
w ,POTENTIOMETRIC SURFACE

- ^ ^^ MHM

)FT1
e^" SHORELINE
10 FT. MEAN SEA LEVEL

\ 400 FT.
\
FRESHWATER
«J
^-^.
)FT '

MEAN SEA LEVEL 1 FOOT DECLINE OF

POTENTIOMETRIC
FRESH-
40H SURFACE I
WATER

FRESHWATER

-CONFININ6--
LAYER ----

FRESHWATER|j
40 FOOT RISE OF
SALTWATER-FRESHWATER INTERFACE
SALTWATER
440

Figure 3. Schematic diagrams showing (A) Relation between saltwater

and freshwater illustrating the Ghyben-Herzberg principle,
and (B) and its effect in an artesian aquifer where
potentiometric surface has declined.
 WELL A WELL B WELL C WELL D WELL E

Figure A. Schematic diagram illustrating migration of poor quality

water by upward leakage through corroded casings or
improperly constructed wells.
10
 Well D. Properly constructed artesian well cased through the upper
aquifers and confining layers with open hole only into the saltwater in
the upper part of the artesian aquifer. Saltwater flowing upward con-
taminates both shallow artesian and water-table aquifers through corroded
casing. This well is not flowing at the surface but has the potential
to flow if the potentiometric surface (water level) rises.

Well E. Abandoned artesian well cased through saltwater of secon-

dary artesian aquifer and confining layer with open hole into the upper
section of the Floridan aquifer. Although this well does not flow at
the surface, internal or interaquifer flow is taking place. Saltwater
is flowing up the well bore and contaminating, by internal leakage
through corroded casing, freshwater in the shallow artesian and water-
table aquifers.

Some .possible combined effects of pumping and internal flow on

aquifer contamination are schematically illustrated in figure 5.

Well I. Saltwater migrating toward the pumping well from a nearby

non-pumping well. The source of saltwater is an abandoned deep well
with leaky casing (well I 1 ).

Well I*. This well is contaminating the secondary artesian aquifer

by upward flow outside the casing and the water-table aquifer by flow
through leaking casing.

Well II. Migration of saltwater from leaky abandoned deep well

(well I') towards the shallow well.

Well III. Pumping well tapping the secondary artesian aquifer and
the artesian aquifer. Water from this well is being contaminated by
downward and lateral migration of saltwater from abandoned well III'.

Well III*. Abandoned well with corroded casing. The leaky upper
casing allows saltwater from the water-table and shallow artesian
aquifers to contaminate the underlying freshwater in the secondary
artesian aquifer by downward leakage. The source of the saltwater in
the shallow aquifers is from adjacent tidal saltwater bodies. (Hydraulic
condition shown in well III' is not related to well IV.)

Well IV. Abandoned supply well showing migration of ^contaminated

water entering the well from the lower saltwater zone of the secondary
artesian aquifer and entering the shallow artesian aquifer through leaky
casing. Contamination of the water-table aquifer is also occurring
through leaky casing.

Well V. Pumping well tapping the secondary artesian aquifer.

Source of the contamination is. saltwater leaking from well IV into the
shallow artesian aquifer. The water enters well V through corroded and
leaky casing.

11
 WELL I WELL I' WELL 11 WELL HE WELL IE' WELLE WELLY

Figure 5. Schematic diagram illustrating variations of

internal flow induced by pumping.
12
 Although surface flow often can be measured readily, internal flow
is more difficult because variations in construction, aquifer character-
istics, and corroded casings. Nevertheless, some measurements of internal
flow from one aquifer to another have been made in wells by current
meters and geophysical equipment and on an areal basis by water quality
criteria. Water loss to overlying aquifers by leakage is discussed
under Quantity of Water Discharged.

AREAS OF UNCONTROLLED FLOWING WELLS

Density and Distribution of Wells

Water will flow at the surface from wells tapping the Floridan
aquifer in 19,700 mi2 , or 36 percent of the state (Healy, 1975).
Principal areas of surface flow include the Atlantic east coast and the
southern third of the peninsula (fig. 6).

Uncontrolled flowing artesian wells were reported in 44 counties in

1956-57 (Hendry and Lavender, 1959, p. 29, table 2). The statewide
distribution of wells flowing at the surface and internally, by counties
(fig. 2) shows that a large percentage of the wells is in two areas in
east coastal Florida, extending from Nassau to Martin Counties, and in
the southwest along the Gulf coast extending from Hillsborough to Lee
Counties. At least 250 or more uncontrolled flowing artesian wells are
in each of 10 of the 14 counties comprising the two areas. The areal
distribution and density of flowing wells generally coincide with the
extent and location of shallow aquifers used for water supply (figs. 1
and 2).

The geographic distribution of the areas where internal flow occurs

is critical. In south Florida, surface and internal flow results in
deterioration of the quality of water in the shallow aquifers. Presently
these aquifers are the only sources of fresh ground water in coastal
areas where extensive development is now occurring and expected in the
next 10 to 15 years.

Estimated Number of Wells

About 15,000 uncontrolled flowing artesian wells 1,883 inventoried

by Hendry and Lavender (1959) and 13,155 estimated by U.S. Geological
Survey are flowing at the surface and internally (fig. 2). About 75
percent of the estimated number of flowing wells are in areas considered
to be principal problem areas deficient in freshwater resources (fig.
7).

13
 I I
A L A B A M A

G E 0 R G I A

i.-lti'!^".c-Xi_^--^:«
30*

29*

28*

EXPLANATION

AREA OF ARTESIAN FLOW Extent and

distribution of areas of artesian flow vary with
27' fluctuations of the potentiometric suface. Areas
of artesian flow adjacent to springs, many rivers,
and coastal beach ridge areas have not been
included, (After Heoly, 1975 ).

26'

29*

85* 84* 83* 82* 81" 80*

Figure 6. Areas of artesian flow from the Floridan aquifer, May 1974.

14
 GEORGIA

jPi \ HAMILTON f

30*

29'

170

EXPLANATION

Principal types of problems

ra Contamination by surface flow and

internal leakage.
Loss of potable water by surface
and internal leakage. ~"f3"HIGHLANDS \ *f\

27'
Loss of potable water by surface
flow.

Estimated total flow (surface and

internal) exceed I million gallons per day.
Number is estimated total flow in
26' million gallons per day.

25'- 0 O 20 90 40 90 MILES

87' 8S» 89* 84« 83* 82* 80*

Figure 7. Principal problem areas of uncontrolled flowing artesian wells.

15
 Quantity of Water Discharged

Surface Flow

Two types of flow from wells tapping artesian aquifers are dis-
cussed surface flow and internal flow. According to Hendry and Lavender
(1959, p. 29, table 2), surface flow from 1,883 continuously flowing
wells measured nearly 80,000 gal/min (115 Mgal/d) or about 42 gal/min
per well. The quantity of water flowing at any given time depends on
the altitude of the potentiometric surface. Hendry's statewide surface
flow figure probably represents higher than average flow per well
because of the subsequent decline of the potentiometric surface in many
areas during 1959-77.

Presently (1978), the U.S. Geological Survey estimates there are

15,000 uncontrolled flowing artesian wells discharging a total of 790
Mgal/d internally and onto the surface in Florida. Surface flow,
statewide, which includes both potable and brackish waters, accounts for
approximately 180 Mgal/d of the total. In contrast to the total state-
wide water pumped for use (3,318 Mgal/d, Leach, 1978), and by spring
discharge (5,000 Mgal/d, Rosenau and Faulkner, 1974), water flowing to
waste from uncontrolled flowing wells is more than 9 percent. However,
when compared with the total withdrawn by pumpage only, that amount lost
by uncontrolled flowing wells becomes far more significant, approxi-
mately 24 percent.

The estimated surface flow from uncontrolled flowing wells is 90

Mgal/d in the 14 counties which include significant problem areas. In
at least 13 more counties, the artesian flow at the surface from uncon-
trolled wells exceeds 1 Mgal/d. For the rest of the State, total surface
flow is estimated at 15 Mgal/d. High rates of artesian flow are con-
centrated along the east coast and in areas along and adjacent to the
southwest Gulf coast (fig. 7).

In several counties the primary problem is the loss of potable

water to the surface rather than contamination of overlying aquifers by
internal flow. In Duval County, the freshwater loss from uncontrolled
artesian wells in the Jacksonville area, was estimated to be as much as
20 Mgal/d, with an uncontrolled average flow rate of 10 gal/min from 2-
inch diameter wells and as much as 300 gal/min from 4- to 6-inch diameter
wells (Leve and Goolsby, 1969, p. 29-30).

In Lee County, the flow from 103 inventioned artesian wells is

primarily brackish and averages about 233 gal/min (0.33 Mgal/d) with
rates ranging from 20 to 750 gal/min (Boggess, 1974, p. 52).

16
 Internal Flow

Many wells that flow at the surface also flow internally through
leaky casings. In Lee County, there are about 3,000 wells and test
holes most of which leak internally (Boggess, oral commun., 1977).

Sproul and others (1972, p. 10) state that in Lee County, "Only
small quantities of water are withdrawn from the lower Hawthorn aquifer
at the present time (1970). However, water is discharged from this
aquifer by upward leakage from the uncased portion of wells. The amount
of leakage in individual wells, as measured by geophysical logging
methods, ranged from about 30 gpm to nearly 100 gpm. Flows less than 30
gpm could not be measured reliably with the instruments used, but it may
be assumed that such flow does occur in most wells penetrating the
aquifer. Assuming an average leakage rate of only 30 gpm per well, and
that at McGregor Isles 40 wells are open to both the upper and lower
Hawthorn aquifers, about 1.7 mgd (million gallons per day) is discharged
from the lower aquifer as vertical leakage. The quantity of water
discharged from the lower aquifer either through wells or along faults
probably will increase as the head in the shallower aquifers is lowered
by pumping."

In Clay County, Foster (1962, p. 7), in discussing loss of water

from leaky wells states, "The estimated water loss in poorly designed
wells ranges from 32 to 180 gpm. Of the 69 wells inventoried, 14 were
found to be leaking, and the total estimated loss of water from the
leaky wells amounts to about 1,000 gpm. It is assumed that 5 percent of
the existing wells were inventoried and it seems probable that the same
percentage of leaky wells would be found among all the wells in the
area. If these assumptions are reasonably correct, the total water loss
would be about 20,000 gpm, or about 30 mgd." According to Foster, about
20 percent of the wells inventoried were leaking internally an average
of 70 gal/min. Internal leakage is not necessarily a "loss" of fresh-
water from the ground-water system, but movement of water from one
aquifer to another as in Clay County. Loss of water would take place if
internal leakage allowed mineralized water to flow through leaky casings
into freshwater aquifers causing a deterioration in the water quality of
the aquifer. Estimated internal flow is 460 Mgal/d in the 14 counties
which include problem areas and 150 Mgal/d for the remaining 13 counties
in central, eastern, and southern areas (fig. 7).

Principal Problem Areas

For the purpose of this report, principal problem areas are those
areas where: (1) Surface flow is at least 1 Mgal/d, (2) upward leakage
of mineralized water from deep aquifers into overlying freshwater
aquifers through leaky well casings or open bore holes has occurred or
is occurring, (3) water levels have declined in shallow and in the
deeper aquifers, and (4) numerous wells either flow at the surface or
flow internally.

17
 The most current priority problem areas of uncontrolled flowing
wells are in parts of Brevard, Charlotte, Clay, De Soto, Duval, Flagler,
Glades, Hendry, Hillsborough, Lee, Manatee, Martin, Nassau, and Sarasota
Counties. In these 14 counties, total estimated discharge from uncon-
trolled flowing wells is 550 Mgal/d of which 460 Mgal/d is internal and
90 Mgal/d is at the surface. Principal problem areas are shown in
figure 7 and are tabulated by counties in table 1.

METHODS OF CONTROLLING FLOWING WELLS

Several methods may be used to control the surface and internal

flow of wells. In determining which method to use, the well bore must
first be examined with several geophysical logging devices to determine
the length and condition of the casing and those horizons where water
may be entering the well. If the casing is intact and of proper length,
and effectively sealing off strata that contain undesirable water, the
well may simply be capped or valved. Capping and valving methods of
flow control do not offer a satisfactory solution when the casing is
corroded or otherwise defective. If the casing is corroded or of insuf-
ficient length, or if this information is unattainable, then the bore
hole must be plugged. One method is to place inside the well bore a
plug or series of plugs above (upward leakage) or below (downward
leakage) the horizon or horizons from which flow into the bore is
identified from geophysical logs. The plug can consist of a fast-
hardening cement or some other material and may extend throughout the
entire depth of the well and include open bore as well as cased hole, or
a series of plugs may be used to seal off different aquifers from which
undesirable water may enter the well bore. If a well is capped without
examining and evaluating the condition of the casing, the capped well
may continue to flow internally and contaminate freshwater aquifers with
mineralized water. In discussing control procedures for eliminating the
intrusion of saline water from deep aquifers, Sproul and others (1972,
p. 27) state, "...capping a well at the surface in no way diminishes the
effects of intruding water into the upper Hawthorn or sandstone aquifers,
and may actually exacerbate the problem."

Cap and valve control are the lowest cost means of controlling
surface flow but will not control internal flow. Well plugging offers
the most effective but most expensive method of controlling both surface
and internal flow. In 1977, costs for plugging with cement varied from a
few hundred to thousands of dollars per well depending upon the length
of the well bore to be sealed. According to the Sarasota County Health
Department (R. Walcott, oral commun., 1977), plugging 5 wells throughout
their entire length cost $6,000. Costs vary from area to area depending
upon the complexity of the problem and the combined experiences of the
driller and of water-management personnel working in programs for
controlling flowing wells.

18
 Table 1. Summary of pertinent data on uncontrolled artesian flow in principal problem areas in Florida by countie

Number of uncontrolled
Estimated flowing wells Estimated Flow
affected area Inventoried; Estimated; artesian flow Aquifers
County (mi 2 ) Hendry 1959 USGS J977* (Mgal/d)!/ fype Depth (feet) Effect of flow affected Remarks
Brevard 150 155 1/3,000 170 Internal, 250-1,400 Decline in water Shallow aquifers, Area affected - southern coastal Brevard County
surface levels, increase upper Floridan south of 28°15' N. Wells used by developers and
in chlorides by aquifer. old tomato farms 20 percent, mosquito control wells
internal leakage. 80 percent. Upward leakage from partially cased
wells. Floridan aquifer salting up in upper zones.
Shallow aquifers being contaminated in east Brevard
County. Chloride in flowing water reported to have
increased 500-2,000 Mg/L in 20-30 years.
Charlotte 260 81 800 45 Internal, 250-900 Contamination by Water-table and Area affected - coastal and central Charlotte
surface internal leakage. shallow artesian County. Sutcliffe (p. 42-44, 1975). In late
aquifers. 1950's General Development Corporation plugged many
flowing wells. Maximum flow of 100 gal/min re-
ported.
Clay 150 40 - 275 32 Internal, 275-600 Wastage of potable Floridan aquifer. Area affected - east Clay County. Estimated
surface water by internal leakage to aquifers overlying the Floridan
leakage and sur- aquifer 30 Mgal/d. Foster (1962).
face flow.
DeSoto 175 138 400 13 Internal, 250-600 Wastage of potable Water-table aquifer, Area affected - southwest DeSoto County (Wilson
surface water, contamina- upper unit of the p. 90, 1977) poor quality water discharging in-
tion by internal Floridan aquifer. ternally as well as at the surface. Mostly
leakage and sur- irrigation and stock wells.
face flow.
Duval 14° 30 200 20 Internal, 300-600 Wastage of potable Shallow aquifers. Area affected - Jacksonville and Duval County.
surface water by surface parts of the Problems include: Uncontrolled flowing wells;
flow, contamina- Floridan aquifer. interaquifer and intraaquifer flow - with salty
tion by internal water (up to 1,000 Mg/L) flowing into zones of
leakage, decline water with 20 Mg/L; poorly constructed walls
of water levels. with upward leakage; walls with internal flow
into aquifers, offshore and beach wells where
tidal fluctuations influence direction of flow.
Estimated flow 15 Mgal/d (Leve and~Goolsby, 1969).

Flagler 50 22 200 22 Internal, Contamination by Nonartesian Area affected - coastal-municipal well field
surface inu-rnal Leakage, aquifer. reported to be affected by deep flowing artesian
surface flow. wells from Floridan aquifer, at Flagler Beach
(Bermes and others, p. 86, 1963). Possibly a
number of uncontrolled flowing wells in vicinity
of Haw Creek.
Glades 150 26 "0 18 Internal, f,00- 1.200 Cont.-.mi n.-it ion hv Shallow aquifers. Area effected - southwest Glades County (Klein
surface internal le;ik:i R e, and others, 1964).
surl.-u-e flow. /
Hendry 200 37 400 60 Internal 400-700 Contamination Shallow aquifers Area affected - Caloosaha tehee River Basin, north-
surface hy inu-rnal and upper part west Hendry County (Klein and others, 1964). Leaky
leakage and of Kl-ridan and nonoperative valves, partial casing or none
wnsu.no of aquifer. reported. Hendry County Environmental Natural Re-
and Advisory Council considering a well
plugging ordinance.
 Table 1. Summary of pertinent data on uncontrolled artesian flow in principal problem areas in Florida, by counties. - Continued

Number of uncontrolled
Estimated flowing wells Estimated now
affected area Inventoried; Estimated; artesian flow From Aquifers
County (mi 2 ) Hendry 1959 USGS 1977 (Mgal/d)!/ Type Depth (feet) Effect of flow affected Remarks

Hillsborough 130 19 400 23 Internal, 200-600 Contamination Shallow aquifers Area affected - southwest coastal Hillsborough
surface bV internal overlying the County near Ruskin and Cockroach Bay west of
leakage and Floridan and upper Highway 201. Wells that flow periodically but were
wastage of parts of Floridan. not flowing at the time of inventory (Feb., 1975)
potable water are Included. Estimated maximum total surface
by surface flow 17 Mgal/d. Estimated .internal flow 6 Mgal/d.
flow. ' - eastern Hillsborough County. Well
plugging program reduced flow from 45 to 14 Mgal/d.

Lee 175 166 3,000 90 Internal, 400-1,200 Contamination Water-table aquifer, Area affected - coastal Cape Coral area, central
surface bX internal unconfined aquifer, Lee County, valley of Caloosahatchee River. De-
leakage and secondary artesian tails of flow are given on page 24. Lee County
surface flow . aquifer. Commission considering an ordinance for plugging
wells. Saline water intrusion related to well
construction (Boggess and others, 1977). Water
supply problems in southwest Florida are discussed
by Boggess (1968) and in Lee County (Boggess, 1974).

Manatee 110 50 325 18 Internal, 200-600 Contamination Shallow aquifers Area affected - estimated 50 wells with uncontrolled
surface bV leakage and overlying the surface flow and 200 wells leaking internally.
surface flow. Floridan aquifer. Much of area was formerly farming now developed
or unused farms with uncontrolled flowing wells.
Problem areas include: Along the Braden River,
coastal area including the barrier island, and
inland areas of county. Wells cased to 200
feet, open hole to 600 feet, into the Floridan
aquifer. Highest flow in September, lowest flow
in May. Two persistent discharge areas may be
attributed to discharge by leaky wells (Peek,
1953).

Martin 26 100 10 Internal, 700-1,485 Contamination Water-table aquifei, Area affected - coastal in vicinity of Stuart.
surface by internal shallow aquifer. Shallow aquifer contaminated by deep flowing
leakage. well tapping the Floridan aquifer, according to
surface flow. Lichtler (p. 72, 1960). Well plugged, chloride

There was no upward leakage through confining

bed overlying the Floridan aquifer at Stuart;

(Lichtler, p. 45, 1960).

Internal, 500-1,800 Contamination by Upper zones of Area affected - coastal Fernandina Beach and central
surface upward leakage. Floridan aquifer. Nassau County. Industrial wells mostly with inter-
nal flow of salt water from lower to upper zones
of Floridan aquifer. (Leve, Oral commun., 1977)

Contamination by Shallow aquifers. Area affected - coastal and western Sarasota

Internal, upward and County. Three areas important: southern and
surface lateral internal western part of Sarasota County north of Philllpi
leakage. Creek; at Osprey waters high in sulfates leak-
Ing upward to ponds; area east of Venice.
if Includes surface and internal flow
~2/ Many wells capped, valved and plugged (1959-1977)
~ by individual owners
3/ Estimated, Foster, 1962, p.7.
 PROGRAM FOR CONTROLLING FLOWING WELLS

The problem of flowing wells is primarily the end result of poor

well construction; that is, wells constructed without valves, with
inadequate casing, with casing not properly seated or cemented, with
casing that corrodes, and otherwise not drilled and constructed to
conform to the local hydrologic and geologic conditions. Many of the
flowing wells were constructed a number of years ago before there was
full recognition of the problem that would be generated and which has
been accentuated by the large increase in demand for freshwater.
Further, lack of regulatory controls on well construction tended to
promote promiscuous and competitive drilling which often resulted in poor
well construction.

Recognition of the need for well construction commensurate with the

hydrologic and geologic environment is inherent in the creation of the
Water Management Districts, under the Florida Water Resources Act of
1972, Chapter 373, Florida Statutes. Under this act the Water Management
Districts have the authority to permit consumptive use of water, part of
which involves issuance of well permits which specify well construction
in conformance with the geologic and hydrologic conditions. Also under
this act, the Water Management Districts have the authority to require
that flowing wells be equipped with valves to control waste or be plugged
if the water is of poor quality and no longer a usable water supply.

Programs for the control of flowing wells are being carried on by

federal, state, county, and municipal agencies in 21 counties and
principal problem areas. The scope of individual programs in six
counties are briefly summarized by counties in table 2. One well
plugging program, QWIP, quality of water improvement program, in opera-
tion since 1974, is being operated by the Southwest Florida Water
Management District in cooperation with their pertinent basin boards and
counties.

Another program, the Agriculture Conservation Program (ACP),

formerly the Rural Environmental Assistance Program (REAP) of the U.S.
Department of Agriculture, Soil Conservation Service, began in 1971 in
Lee County and has continued yearly except in 1973 and 1975. In addition
to those counties shown on table 2, the ACP program is currently active
in Brevard, Clay, Collier, De Soto, Flagler, Hendry, Indian River, Lake,
Martin, Okeechobee, Putnam, St. Johns, St. Lucie, Seminole, and Volusia
Counties. As of February 1978, flowing wells have been plugged in
several counties as follows: Brevard, 3; Charlotte, 4; Collier, 2;
Hendry, 1; Lee, 23; and St. Johns, 7 (Wyatt Thomas, oral commun., 1978).

The quality and efficacy of well construction depends primarily on

the expertise and competency of the driller. As part of the statewide
effort to maintain acceptable drilling standards and responsibilities
of the driller, the Department of Environmental Regulation, issued about
79 new and renewed 750 driller's licenses, during July 1975-January 1978.

21
 Table 2. Summary of current programs for the control of flowing wells in Florida, by counties

Date
Type program Type
County Agency agency began problem Remarks - program activities

Charlotte Southwest Florida Water 1974 Contamination Purpose, to control surface flow and
Water Management Management of aquifers internal flow, prevent contamination
District (SWFWMD), District by surface and of shallow aquifers by waters high
Quality of Water internal flow in chlorides and sulfates. As of
Improvement 1977, 400 wells inventoried, 63 wells
Program (QWIP) required plugging, 39 wells plugged -
in cooperation program continuing. Wells logged
with Peace River prior to plugging.
Basin Board,
USDA SCS Federal 1972

NJ Duval City of Municipal 1975 Surface flow Purpose, to prevent surface flow of
N)
Jacksonville, of good potable water. 98 free-flowing wells
Health, Welfare quality water, reported. As of October 1977, 12
and Bioenviron- internal flow, wells reported plugged. Wells logged
mental Services, saltwater prior to plugging. Well owners
Water Conserva- contamination responsible for plugging well in
tion Authority presence of representative of
Jacksonville. Plugging done by
private driller.
Hillsborough SWFWMD, (QWIP), Water 1975 Waste flow Purpose, to prevent surface flow of
(Eastern) in cooperation Management of good potable water from Floridan aquifer.
with Alafia District quality water As of 1977, 700 abandoned or flowing
River Basin wells inventoried; 206 wells need
Board, USDA SCS Federal repair; 147 flowing wells capped.
Estimated original flow of 45 Mgal/d
reduced to 14 Mgal/d. Well capping
program continuing.
Table 2. Summary of current programs for the control of flowing wells in Florida by counties - Continued

Date
Type program Type
County Agency agency began problem Remarks - program activities

Hillsborough Hillsborough County, 1975 Contamination Purpose, to control surface and sub-
(Western County Technical Water of aquifers surface flow and prevent deteriora-
Coastal) Support Program Management by surface and tion of shallow aquifers. 70 wells
in cooperation District, internal flow. inventoried. Well logging and plug-
with SWFWMD, Federal ging program continuing.
USGS, USDA SCS

Lee U.S. Dept. Federal, 1971 Surface flow, Purpose, prevent wastage by surface flow,
of Agriculture County contamination prevent deterioration of shallow
Soil Conserva- of shallow aquifers. About 29 wells plugged since
tion Service aquifers by 1971. Program national in scope, con-
internal flow. tinuing. Lee County Commission con-
sidering an ordinance for plugging wells.

City of Cape Municipal Contamination Purpose, to reduce contamination of

Coral of aquifer by upper Hawthorn aquifer from salt-
internal flow. water flowing internally from
corroded casings.
Manatee Manatee County County, 1977 Surface and Purpose, control of flowing wells
in cooperation Water internal flow, and reduction of contamination of
with Manasota Management contamination. aquifers overlying the Floridan
Basin Board and District aquifer. Inventory of flowing wells
SWFWMD (QWIP), continuing. 5 wells logged and to be
USDA SCS Federal plugged. 2 wells plugged on Anna Maria
Island at Coquina Beach by QWIP.
Sarasota Sarasota County County, 1976 Surface flow, Pilot program to determine cost of
Health Depart- Water internal flow. plugging wells. 5 wells plugged.
ment in coopera- Management 3 or 4 more wells to be plugged.
tion with District Cost of plugging 5 wells - entire
Manasota Basin length, $6,000.
Board, USDA SCS Federal
 SUMMARY

An estimated 15,000 uncontrolled flowing wells, wastefully dis-

charge about 790 million principal of water per day by surface and
internal flow. Internal flow discharges into shallow artesian and
water-table aquifers through leaky casings or open well bores. Total
flow in principal problem areas in 14 counties is estimated at 550
million gallons per day, or 70 percent of the statewide total.

A large percentage of the discharge from uncontrolled flowing wells

is concentrated in the east-coastal and southwest coastal counties of
Florida. Fourteen principal problem areas have been identified in
Brevard, Charlotte, Clay, De Soto, Duval, Flagler, Glades, Hendry,
Hillsborough, Lee, Manatee, Martin, Nassau, and Sarasota Counties.

Any natural or artifically induced factor that affects water

resources, particularly by causing deterioration in quantity or quality
of water, requires particular surveillance and careful management
practices. Management is necessary to prevent deterioration of the
resources. In many areas, uncontrolled discharge over the years has
caused a decline in the potentiometric surface and a deterioration of
the potable water aquifers.

24
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25
Peek, H. M., 1953, The artesian water of the Ruskin area of Hillsborough
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26

*U.S. GOVERNMENT PRINTING OFFICEi 1979-641/322/6231. REgion