<%BANNER%>

STATE OF FLORIDA
STATE BOARD OF CONSERVATION
DIVISION OF GEOLOGY




FLORIDA GEOLOGICAL SURVEY
Robert 0. Vernon, Director




REPORT OF INVESTIGATIONS NO. 41




WATER RESOURCES
OF THE
ECONFINA CREEK BASIN AREA
IN
NORTHWESTERN FLORIDA
By
R. H. Musgrove, J. B. Foster, and L. G. Toler


Prepared by the
UNITED STATES GEOLOGICAL SURVEY
in cooperation with the
FLORIDA GEOLOGICAL SURVEY

TALLAHASSEE
1965










FLORIDA STATE BOARD

OF

CONSERVATION


HAYDON BURNS
Governor


TOM ADAMS
Secretary of State




BROWARD WILLIAMS
Treasurer




FLOYD T. CHRISTIAN
Superintendent of Public Instruction


EARL FAIRCLOTH
Attorney General




FRED O. DICKINSON, JR.
Comptroller




DOYLE CONNER
Commissioner of Agriculture


W. RANDOLPH HODGES
Director






LETTER OF TRANSMITTAL


'9orida jBeological QuTrvey

TALLAHASSEE

July 20, 1965

Honorable Haydon Burns, Chairman
Florida State Board of Conservation
Tallahassee, Florida

Dear Governor Burns:

The Florida Geological Survey will publish, as Report of Investi-
gations No. 41, a comprehensive report on the water resources of the
Econfina Creek Basin area in northwestern Florida. This report was
prepared by the members of the U. S. Geological Survey in coopera-
tion with the Florida Geological Survey, as a part of its water
resources study program.
The Econfina Creek is one of the largest discharging streams of
the State, and its potential for meeting water resources needs is great.
The publication of the total resources study, to be accomplished in
a series of papers, will contribute toward the stabilization of the
economic development of the Panhandle area, and will provide a
basis upon which a large water-using economy can be based.

Respectfully yours,
Robert O. Vernon,
Director and State Geologist




























Completed manuscript received
April 30, 1965
Published for the Florida Geological Survey
By The St. Petersburg Printing Co., Inc.
St. Petersburg, Florida
1965





PREFACE


In the planning and preparation of this report we have tried to
present the essential information that would provide a brief, concise
description of the water resources of the Econfina Creek basin area.
The report was designed to supply answers to general questions of
the many people interested in the water resources of the basin. Other
reports on particular aspects of the water resources of the basin will
present more detailed information about a phase of the hydrology or
geology of the basin. This report is intended to furnish the back-
ground from which the reader may refer to the phase reports for more
definitive treatments of a particular subject.
Special phases of the water resources of the basin will be featured
in reports on: Deer Point Lake; The Deadening area of southeastern
Washington County; geology and aquifers of Bay County; and a
quantitative study of ground water in the Panama City area. In addi-
tion, the basic data available through the period of investigation
will be published in the information circular series of the Florida
Geological Survey.
This report was prepared by the Water Resources Division of the
U. S. Geological Survey in cooperation with the Florida Geological
Survey. The investigation was under the general supervision of Robert
0. Vernon, Director, Division of Geology, State Board of Conserva-
tion; A. 0. Patterson, district engineer, Surface Water Branch; C. S.
Conover, district engineer, Ground Water Branch; and K. A. Mac
Kichan, district engineer, Quality of Water Branch, of the U. S.
Geological Survey.
A number of individuals and organizations have been most gener-
ous in supplying information, equipment, and time in the process of
collecting data for this report. The courtesies extended by the follow-
ing persons are most appreciated: W. C. Cooper of W. C. Cooper
Plumbing and Heating Co.; H. L. Berkstresser and W. H. Galloway
of the Water and Sewage Department of Panama City; G. Layman,
construction engineer for Gulf Power Co.; W. H. Toske and M. G.
Southall of the U. S. Navy Mine Defense Laboratory; R. B. Nixon
and J. L. Gore of the Tyndall Air Force Base water department; J. M.
Lowery and T. M. Jones of the International Paper Co.; A. G. Symons
and R. H. Brown of the Layne-Central Co.; W. Brown of the Brown
Well and Pump Co.; and J. W. Spiva of Modern Water Inc.
Data on the chloride content in water from Deer Point Lake
during the period of freshening were furnished by the Florida State
Board of Health.

V







PREFACE


We would like to express special appreciation to Judge Ira A.
Hutchison who through his interest in water resources and in par-
ticular the geology of this area has been most helpful. Claude Hicks
has volunteered invaluable assistance in the collection of water-level
information in the Deadening lakes area.
We would like to thank the numerous citizens in the basin who
gave us access to their wells and who furnished us with information
on their water supplies.







CONTENTS

Page

Preface .............. ---... ---...---- --......--.. .-----..-..-.---- v

Abstract ...-....................... .-------------------------- --- ............-- ........... 1

introductionn ---...........---..-.........- ....... .... ---. ---.. .........---- 2

The hydrologic environment ---..--............-..-..------------------- 4

General statement ..........................---------- ----------- 4

Physical make-up of the basin ...........-............------ ---..-- ..----... 4

Water movement .-.....---....--------------------------- 7

Water availability .........--....................- ----- ---------------- 8

Rainfall ...................... ........ ..... ..---- --------- --------- ------- 8

Water quality characteristics .--..-...-....-........-------- .--------- 9

Contamination by saline water .-......-...............----.........------- 11

Streamflow ..-.......-...--------..........----- ------------------ 15

Storage -..~.......---.......-.....-- .--.-------- ---------------- 18

Lakes ..--............ .. -------.---. --------- -------- 18

Aquifers ......-...........--..-- -------------- -------- 19

Aquifer characteristics ................---------------------------- 20

Hydraulics of aquifers ......-........-- .....--.--- ---- ------------22

Aquifer tests ....-...................-- ..-------------------- 24

Water use ......................---------- ---------------------------- 27

Water high lights of the basin .--.............-... --------------------- 29

Decline of water levels in the Panama City area ...---...---...--...--..-.......----.. 29

General statement .........-- ........---------------------- 29

History of ground-water development ..--------................. .............31

vii








Page

The Deadening lakes ...................................... ..............---- 35

Geologic and hydrologic setting ..--......--..-..........---------------- 37

Water levels ...--............---.......--------------------- 37

Flow of Econfina Creek .......-.................------- -------------40

Springs ---..........-...--..--..-...-------------- -----------41

Deer Point Lake .........--.....---- ---------------------- 45

Summary -..-----.---- -------------------------.----- 45

References .......-..---........----------------------------- 51







































viii








ILLUSTRATIONS

Figure Page
1 Map of Econfina Creek basin area ........--......................---............. 3

2 Map of Econfina Creek basin showing physiographic divisions and
surface runoff --................. ....-- .-..-- ..--.......--.......-....--.................. Facing p. 4

3 Geohydrologic sections of Econfina Creek basin area --...-..-.......----...--...-- 6

4 Bar graphs of maximum, minimum, and average monthly rainfall, and
annual rainfall, at Panama City from 1935 to 1963 ....-...-- .....-- ..---------...... 9

5 Map of Econfina Creek basin area showing location of data-collection
points referenced in report -....--.......-...-..----.....--.....---------------...............-.... 12

6 Scatter diagram showing relation of chloride to total mineral content
of water from the Floridan aquifer in the Econfina Creek basin area .... 13

7 Block diagram of Econfina Creek basin showing areal distribution of
mineral content and chloride concentration in water from selected wells
in the Floridan aquifer -....--...--.............- .......- ................... -......... ......-- 14

8 Graphs of chloride concentration in water from selected wells in the
Floridan aquifer .............------..--.......-....-........--......-- .. ....------------.---- 15

9 Flow chart of streams in the Econfina Creek basin -..-....--...---........-....-- ... -- 17

10 Graphs of water level in the water-table aquifer and rainfall near
Bennett for part of 1962 and 1963 ..----.......----......................--.......-- .-- 19

11 Graph of streamflow of Econfina Creek near Compass Lake for the
period April 1 to May 7, 1963 ......-..-...-........--------..-- ..-- .------. -----. 20

12 Sketch showing similarity of an artesian pressure system and water
pressure developed by an elevated tank .--..........---.................------ ..------ 21

13 Map showing the piezometric surface of the Floridan aquifer in the
Econfina Creek basin area, October 1962 ...----.........-..---...--...-...--- --.-- 23

14 Graphs showing theoretical drawdowns in the vicinity of wells being
pumped at a constant rate for selected periods .....-...-.....-...........-...-- ...... 26

15 Theoretical drawdowns along a line of 10 wells after 100 days of
pumping at a rate of 200 gallons per minute at each well -..--.....-..--.... 27

16 Graphs of water use and population in the Panama City area -...-....-.... 30

17 Map of the Panama City area showing the location of water wells for
each water system and the area supplied by these systems -..--..-..........--.. 31

18 Map showing the approximate piezometric surface of the Floridan
aquifer in the Panama City area in 1908 ---.........---..-.--... -~.. ------. 32

ix








Figure Page

19 Graph of water levels in observation well 008-537-332 near the center
of the International Paper Company well field for the period 1951
to 1963 .-..-..-.........................- .................-........-..............................----........... 33

20 Map showing the piezometric surface of the Floridan aquifer in the
Panama City area in April 1947 ....-......--.......-...................--...-..................... -35

21 Map of White Oak Creek basin in southeastern Washington County
showing The Deadening area ..-..-.........-................. .... ...-------........................ 36

22 Geohydrologic sections through the White Oak Creek basin, south-
eastern W ashington County .............................-.............. .......-- ......----- -....... 38

23 Graphs of water levels and rainfall in the vicinity of the Deadening
lakes .....----------------------.. ....... .... .............. ....................... ................. ........ 39

24 Flow chart of Econfina Creek during the low-water period of May 1963
showing the effect on streamflow if 30 mgd were diverted at the proposed
dam site .---------.--....... -............-----------------------..................................... 42

25 Flow chart of Econfina Creek showing spring flow ......-............................... 43

26 Graphs of streamflow, spring flow, and specific conductance for Econfina
Creek near Bennett for 1963 ..----.......................... ................- ...................... 44

27 Graph showing the relation of chloride in water in Deer Point Lake to
fresh water inflow --...-----.. .... ...........-----------------.......................... 46

28 Graphs showing the rise of water levels and change in chloride content
of ground water after construction of Deer Point Dam ...............--.....-..-- .. 47



TABLES

Table Page
1 Drainage areas, average flows, and low flows of subbasins within the
Econfina Creek basin ------ -----............-------------------.................................. 16

2 Record of water supply systems in the Econfina Creek Basin area .......... 28








WATER RESOURCES
OF THE
ECONFINA CREEK BASIN AREA
IN
NORTHWESTERN FLORIDA

By
R. H. Musgrove, J. B. Foster, and L. G. Toler

ABSTRACT
The Econfina Creek basin area of about 1,000 square miles is
located in northwestern Florida. Water use in the basin in 1963
averaged about 25.2 mgd (million gallons per day). The major uses
of water were for the manufacture of paper products, public and
domestic supplies, and recreation. Of the 25.2 mgd, 22.7 were pumped
from the artesian Floridan aquifer, mostly in the Panama City area.
In February 1964 use of lake water was started at the rate of about
30 mgd and ground-water withdrawal was reduced to about 11 mgd.
Since February 1964 the total use of water in the area has been about
41 mgd.
The basin receives most of its water from rainfall which averages
58.0 inches per year. Highly porous, unconsolidated sands form the
water-table aquifer and absorb much of the rainfall. Seepage from
this aquifer is to the streams and to the underlying artesian aquifers.
The productive artesian Floridan aquifer underlies the entire basin
and is the aquifer from which the most water is pumped. A secondary
artesian aquifer is present in the southern part of the basin and is
intermediate in depth to the water-table and Floridan aquifers. Move-
ment of water through these aquifers is generally southwestward.
By 1963, water levels in the Floridan aquifer near Panama City
had been lowered 200 feet by pumping since the first deep well was
drilled in 1908. The large drawdowns resulted from heavy pumping of
closely spaced wells in this aquifer which has a low transmissibility
(1,300 to 31,000 gallons per day per foot). In January 1964, pump-
age from a field of 21 wells was stopped and water levels in this field
recovered 163 feet within 51 days.
Water from the water-table aquifer generally had a mineral con-
tent from 10 to 50 ppm (parts per million) and that from the sec-

1







FLORIDA GEOLOGICAL SURVEY


ondary artesian aquifer from 80 to 150 ppm. Water from the Floridan
aquifer increased in mineral content from 70 ppm in the northern
part to about 700 ppm in the southern part of the basin. Mineral
content of water from streams and lakes, exclusive of those receiving
artesian spring flow, was from 6 to 25 ppm. Water from springs had
a mineral content from 50 to 68 ppm and was similar to water from
the Floridan aquifer in the upper part of the basin.
Streamflow into the coastal bays is at an average of about 960
mgd. Flow to North Bay is about 680 mgd, of which about 650 mgd
flows through Deer Point Lake. East Bay receives about 210 mgd,
and West Bay about 70 mgd. Runoff from the lower half of the drain-
age of Econfina Creek is 90 inches per year. This is about three times
the runoff from the upper half of the basin and is a result of artesian
spring flow.
There are about 80 named lakes in the basin, some of which have
a wide range in stage. A plan has been proposed to divert water from
Econfina Creek to a group of these lakes in southeastern Washington
County to stabilize their levels. At the proposed point of diversion,
Econfina Creek has a minimum flow of 30 mgd, which would supply
about 0.5 of a foot of water per month on the proposed lake area.

INTRODUCTION
This report describes and evaluates the water resources of the
Econfina Creek basin area located in northwestern Florida. The area
encompasses about 1,000 square miles and includes most of Bay
County and parts of Calhoun, Gulf, Jackson, and Washington coun-
ties, as shown in figure 1. As considered in this report, the Econfina
Creek basin area includes all basins that drain into the bay system
within Bay County.
Over 90 percent of the 70,000 people in the basin are located near
the coast and are centered in the Panama City area. In 1963, water
use in the basin was at the rate of 25.2 mgd. The three largest water
users were the International Paper Company, Panama City, and
Tyndall Air Force Base.
Ground-water levels were known to be below sea level in well
fields supplying the major users. Information was needed to determine
the extent of the low water levels and their effect on the water re-
sources of the area.
More than 80 fresh-water lakes are situated in the higher parts
of the area, mostly in southeastern Washington County. Included
is a group of lakes locally known as The Deadening. Considerable







REPORT OF INVESTIGATIONS No. 41


Figure 1. Map of Econfina Creek basin area.


interest has been expressed concerning the development of The Dead-
ening lakes into a water-oriented recreational area. Widely fluctu-
ating lake levels rendered this recreation plan infeasible without
lake controls. The Washington County Development Authority has
a plan to stabilize these lakes by water diverted from Econfina Creek.
Data were collected during the investigation to evaluate this plan.
No formal reports on the water resources of the area were avail-
able before this investigation. Some data were available on ground-
water levels, streamflow, and the chemistry of ground water. This
report is based on a 2-year investigation which began in January
1962. The investigation was designed to provide a basis for an evalu-
ation of the water resources of the Econfina Creek basin.






FLORIDA GEOLOGICAL SURVEY


THE HYDROLOGIC ENVIRONMENT

GENERAL STATEMENT

Water in the natural state continually moves due to many forces
acting upon it. Gravity acts on water in streams and underground
to keep it moving downward toward the level of the ocean. The sun
and wind evaporate water from open water bodies and plants trans-
pire water to the atmosphere. Gravity again moves the water earth-
ward when the atmospheric moisture meets conditions favorable for
rain. This never ending movement of water is known as the hydro-
logic cycle.
The water resources of any area depend upon this hydrologic
cycle. When the rate of water movement out of an area exceeds the
rate of water movement into the area, water shortages will develop.
Water shortages may also develop if the quality of water is signifi-
cantly altered within its natural environment to make it unfit for its
intended use. Variations in the rate of movement in any phase of the
hydrologic cycle, such as rainfall, may also affect an area by result-
ing in floods and droughts. Proper development of the water resources
of an area requires a thorough knowledge of water movement and
the factors controlling it. This knowledge will enable the best pre-
diction of where to obtain water and what provisions are required
to control water movement.
In general, the system through which water moves in the Econ-
fina Creek basin is similar to most river basins in Florida. Like most
other basins, (1) rainfall is the source of all the water even though
some falls outside the basin and moves into the basin underground;
(2) the surface materials are highly porous, unconsolidated sands;
(3) the basin is underlain by the artesian Floridan aquifer; and
(4) water leaves the basin by streamflow, evaporation, transpira-
tion, underground flow to the ocean and other basins, and by con-
sumptive use.

PHYSICAL MAKEUP OF THE BASIN

Four physiographic divisions within the basin affect the surface
drainage and the water storage. These are the sand hills, sinks and
lakes, the flat-woods forest, and the coastal beach sand dunes and
wave-cut bluffs, shown in figure 2. The physiographic divisions have
developed on a series of stair-step marine terraces which were carved
into the surface sands during the ice age by the successive levels of







55' 50' 45 40 35' 30' 25' 20' 15' 83*0


GREENHEA
30C 3


1 0 2 3 4 5 Miles




25'














EXPLANATION


PHYSIOGRAPHIC DIVISIONS 5

-- -- Sand hills A
SE Sinks and lakes a
B~bl Flat- woods forest
SBeach dunes and wave-cut bluffs

3711Numbers represent average annual
runoff in inches from areas out- TEReWAy
lined by dashed lines
860' 55 50' 45' 40' 35 30' 25' 20' 15' 85 10'

Figure 2. Map of Econfina Creek basin showing physiographic divisions and
surface runoff.


- 1 7 1 1 1 1


86"00'







REPORT OF INVESTIGATIONS No. 41


the ocean. Low swampy areas occur throughout each of these divi-
sions but are more prevalent in the flat-woods forest.
The sand hills in the northern part of the basin are erosional
remnants of the higher marine terraces which were between 100 feet
and 270 feet above the present sea level.
The sinks and lakes occur in the section of the basin west of
Econfina Creek where they have developed within the sand hills. This
area is typified by irregular sand hills and numerous sink holes and
sink-hole lakes. The sink holes range in diameter from a few feet to
broad flat areas such as those in The Deadening lakes area (see p. 73).
This physiographic division was developed by the solution of the
underlying limestone and the subsequent collapse of the overlying
material into the solution chambers. Most of the lakes have no sur-
face outlets.
The flat-woods forest is the largest physiographic division of the
basin. It is slightly rolling to flat land lying on the terraces below an
elevation of 70 feet. Most of this division is covered with pines except
for a few small areas cleared for agriculture. The flat-woods forest is
well drained except for some low areas around the bays on the 0 to
10 and 10 to 25 foot terraces. During rainy weather these low areas
of the flat woods become quite wet. A few small perennial swamps
occur at various locations throughout the flat-woods forest. The larg-
est is Bearthick Swamp southeast of Youngstown which covers an
area of about 2,000 acres (fig. 2).
The fourth physiographic division occurs adjacent to the gulf
coast and is characterized by beach dune deposits and wave-cut bluffs.
The beach dune deposits are the youngest sediments in the basin and
are the most rapidly changing physiographic feature.
The surface materials in the basin, on which the physiographic
features have developed, are generally very porous, permeable sands.
The sands form the water-table aquifer which is thicker in the sand
hills (80 to 100 feet) than in the lower elevations of the flat-woods
forest (10 to 30 feet) and thickens again along the coast (65 to 140
feet). The sands are missing only in stream channels and in some
parts of the broad depressions of the sinks and lakes division.
The sands of the water-table aquifer cover a relatively imperme-
able layer of sandy clay and clayey shell material which forms an
aquiclude (a formation that confines water to aquifers above and
below it) between the water-table aquifer and the artesian aquifers
below it, as shown in figure 3. This aquiclude is present throughout
the basin except where it has been breached by a collapse into solu-
tion chambers or by erosion along Econfina Creek.
















320- NO0
II


240-1 I -240




e~ d t San .-: L1 1 r. -20

BStse(I ..T.11 T I; 320
--160
~ Se-- Sea



40- 2ay 400

~tfLimestone -6
-560


A Is


AQIJICUDE -AQUICLUDE -


~"'ca~tt+~mrm7_rrT-rrIfr


WATE~TA8L AQUF


.3 -320





.640 --640
--.20
01 234 5 10 miles


Figure 3. Geohydrologic sections of Econfina Creek basin area.


Seoll


Io ll


80-
Seo Igl 0-
.80-


-60


-80 3
-160
--240 F
w


. . I. .


I


I


W


n: -- AOQUICLUiE"--"~'.





REPORT OF INVESTIGATIONS NO. 41


In the bay area and along the gulf coast in the basin, two artesian
aquifers are associated with the aquiclude. Here the aquiclude is
thicker than it is to the north and is overlain and in part underlain
by some shell-hash beds which contain water. The sandy clay material
which forms the base of the water-table aquifer is sufficiently imperm-
eable to confine water in the shell-hash beds under artesian pressure.
Water producing zones in the shell-hash beds above the aquiclude
are termed the secondary artesian aquifer. The water producing zones
in the shell-hash beds below the aquiclude are considered part of the
Floridan aquifer.
The Floridan aquifer underlies the entire basin below the aqui-
clude. It is composed of limestone formations that are as much as
1,200 feet thick. However, the usable part of the aquifer, the part
producing potable water, is the upper 500 to 700 feet.

WATER MOVEMENT
Rain, falling on the basin, is readily absorbed by the porous sur-
face sands. The portion that runs off directly to the streams depends
on the amount and intensity of the rainfall. The rain water and the
surface water are relatively pure but contain some salts carried in
the evaporate from the ocean and some gases dissolved from the at-
mosphere. The surface water becomes colored after contact with
decayed organic matter but the mineral content changes very little.
The water absorbed by the sands seeps downward to the water
table, the level below which the sand is saturated. The sands are not
very soluble in the rain water and consequently the mineral concen-
tration in water from the water-table aquifer is low.
Some of the water then moves from the water-table aquifer into
the streams and maintains flow during periods of no rainfall. In the
northern part of the basin where the sand and clay are breached by
sinkholes, some of the runoff and seepage from the sands is tempo-
rarily ponded in lakes and then moves into the Floridan aquifer. In
other areas the water from the sands may seep slowly into the lime-
stone through the clay layer.
The amount of water moving from the water-table aquifer to the
Floridan aquifer diminishes toward the southwest because the aqui-
Sclude is thicker. Water that moves downward into the limestone of
the Floridan aquifer then moves in the down gradient direction shown
by the piezometric map (see p. 23). The gases acquired from the at-
mosphere and from the soil zone form a weak acid solution which dis-
solves the limestone and thereby causes an increase in the mineral
I






FLORIDA GEOLOGICAL SURVEY


content of the water. The mineral content of the water increases in
the down gradient direction as more limestone is dissolved.
In areas along Econfina Creek where the artesian pressure surface
is above the land surface and the sand and clay are missing, springs
have developed. Most of the flow of Econfina Creek is derived from
these springs.
In the southern half of the basin, water may percolate downward
from the water-table aquifer into the secondary artesian aquifer. The
sandy clay material at the base of the water-table aquifer and at the
top of the secondary artesian aquifer acts as a semi-confining layer
which maintains the water in this aquifer under artesian conditions.
The secondary artesian aquifer is composed of shell-hash with
interlayered sand and limestone lenses. Water that moves into this
aquifer from the water-table aquifer is slightly acid. This water
dissolves the limestone and shell giving the water a calcium bicarb-
onate character.
The water withdrawn from wells in the Floridan aquifer in the
Panama City area entered the aquifer through the sinks in the north-
ern part of the basin and in areas farther north where the limestone
formations are at ground surface. By the time the water reaches
Panama City the mineral concentration is five to six times that of
water in the northern part of the basin. Part of the increase is caused
by solution of the limestone and part is caused by mixing with older
water in the rocks. The pressure gradient shows that the water is being
flushed into the ocean at some point where the rocks are exposed to
or hydraulically connected to the ocean bottom.

WATER AVAILABILITY
The amount of water moving through each part of the hydrologic
system must be known to properly evaluate a water resource. A
knowledge of the environment is necessary to determine the chemical
and physical properties of the water and to predict any changes in
these properties that may result from withdrawal of water from the
system. Some of the parameters that affect the amount and quality
of water available are rainfall, streamflow, water levels, rock com-
position, and the ability of aquifers to store and transmit water.
These hydrologic features can be measured either by direct or in-
direct methods.
RAINFALL
The Econfina Creek basin receives an average rainfall of 58 inches
per year, based on records collected at Panama City by the U. S.






REPORT OF INVESTIGATIONS No. 41


Weather Bureau. During the past 29 years the annual rainfall at
Panama City has varied from 37.6 inches to 85.0 inches. Graphs
showing variations in rainfall are given in figure 4. Short periods

25 100


W 20 w 80
AVERAGE 57.98
Z MAXIMUM-
15 60 F,


1 10j 40---- --- -

5 A

0 0
J FMAIMIJJIAI S7OINID i uA o 0 o 1


Figure 4. Bar graphs of maximum, minimum, and average monthly rainfall,
and annual rainfall, at Panama City from 1935 to 1963.

of low rainfall and short periods of high rainfall have little direct
effect on the water resources; that is, the amount of water in storage.
Extended periods of below-average rainfall, or droughts, cause reduc-
tion in storage. The most severe drought of record ended in 1956
with a 7-year deficiency in rainfall of 50.2 inches. Within this 7-year
period, 1953 was a single year of above-average rainfall but did not
bring about a complete recovery of water lost from storage during
the preceding years of low rainfall. The 6-year period from 1944 to
1949 was the wettest of record. Records of water levels indicate that
storage was near an all-time high during this wet period.


WATER QUALITY CHARACTERISTICS

The water in the lakes and streams of the area has about the
same mineral concentration as rain water. Samples of rain water
contained as much as 13 ppm of dissolved mineral matter; the water
in the streams and lakes ranged from about 6 to 25 ppm. The mineral
concentration of the surface water differs little from rainwater because
of the relative insolubility of the surface materials. During periods
of low flow, high mineral concentrations are normally expected in
stream water because a large part of the flow is seepage from the






FLORIDA GEOLOGICAL SURVEY


water-table aquifer. No difference in the chemistry of surface water
in the basin was noted between high and low flow except for the color
and pH. High color immediately following a rain is attributed to the
flushing of the decayed organic material from the swampy, poorly
drained areas adjacent to the streams. This same colored water tends
to be acid due to the solution of carbon dioxide released from the
decaying plants. The pH of the streams is lower (more acid) during
high flow when the flushing of the swampy areas occurs. The pH
normally ranges from 6.0 to 7.0 units but falls below 6.0 during
these times.
Two areas of exception to the normal low mineral concentration
in stream water occur in the Econfina Creek basin. One of the areas
is along Econfina Creek downstream from a point about due east of
Porter Lake, where the creek receives flow from artesian springs.
These springs emanate from limestones of the Floridan aquifer and
the chemistry and relative solubility of the rocks are reflected in the
mineral constituents found in the water. The mineral concentration
in water from the springs ranged from 50 to 68 ppm and all but about
10 to 12 ppm were calcium and magnesium carbonate, the constituents
of limestone. The mineral content of the water in Econfina Creek,
downstream from where spring water enters, is higher than that in
other streams in the basin, and varies with the ratio of spring flow
to surface runoff. Calculations, based on chemical analyses, (see
p. 84), show that 70 to 75 percent of the base flow of Econfina Creek
at the Bennett gaging station is from springs.
The other area of exception to normal low mineral concentrations
in stream water is near the mouth of the streams which empty into
salt-water bays. Salt water moves up the streams a distance that is
dependent upon the elevation of the streambeds, the stage of the
streams, and tides. This encroachment of saline water occurs in the
mouths of all streams except those emptying into Deer Point Lake,
which is a fresh water body.
That part of the rainwater that replenishes the aquifers continues
to move in the hydrologic cycle but at a slower rate than the water
moving as surface flow. This slow rate of movement allows a state of
chemical equilibrium to be approached and normally results in ground
water having a higher concentration of mineral constituents than does
the surface water in an area. The highly insoluble nature of the sands
which form the water-table aquifer in the Econfina Creek basin
results in low mineral concentration of water in this aquifer. Gen-
erally, the concentration of total mineral constituents in water from
this aquifer ranged from 10 ppm (about equal to that of rainwater)






REPORT OF INVESTIGATIONS NO. 41


,o about 50 ppm. In areas near the coast these sands are in contact
vith salt water. All water from the water-table aquifer which con-
tained more than 50 ppm dissolved minerals was from wells located
within a few hundred feet of salt-water bodies.
Water in the secondary artesian aquifer is slightly more mineral-
ized than water in the water-table aquifer. In some areas near the
coast the water from this aquifer may be saline. Where there is no
contamination by saline water, the water generally contains from 80
to 150 ppm dissolved minerals and is principally a calcium bicarbonate
water. Most of the water samples contained hydrogen sulfide and some
samples contained sulfate.
The mineral concentration of water from the Floridan aquifer is
higher than that from the secondary artesian or the water-table
aquifers. In the northern part of the basin the higher mineral content
is due entirely to higher concentrations of calcium and bicarbonate
resulting from solution of the limestone. There are definite trends in
mineral concentrations in water in the Floridan aquifer. These trends
have been mapped (Toler and Shampine, 1964) and generally show
increases in all constituents toward the southwest. An adaptation of
the map of dissolved solids is shown on page 14 and indicates the
trend of all the constituents. Sulfate, sodium, and hydrogen sulfide
show little trend, but are found in significant quantities in the
southern half of the basin. In this area, sulfate ranged from 0 to
81 ppm, sodium from 2 to 164 ppm, and the odor of hydrogen sulfide
was detected in water from most wells.

CONTAMINATION BY SALINE WATER
The large bays in the southern half of the Econfina Creek basin
provide an access for salt water several miles inland. Along the shore-
line of these bays and along the Gulf, the salt water is in contact with
the sands which form the water-table aquifer. During droughts, when
the water levels in the sands are low, salt water may enter the aquifer
and be pumped from shallow wells near the shore. Salt water is more
dense than fresh water and it moves into the aquifer in the form of
a wedge below a lens of fresh water. Fresh water will generally sup-
press the salt water about 40 feet below sea level for every foot of
elevation of fresh water above sea level. If the water level in the aquifer
is lowered by pumping, the saline wedge adjusts to the new water
levels and salt water may rise to contaminate a well. An interzone of
water of intermediate composition is normally present instead of a
sharp fresh-water salt-water interface.







FLORIDA GEOLOGICAL SURVEY


Salt water may enter the secondary artesian aquifer from the bays
or from the water-table aquifer, when the pressure surface of the
secondary artesian aquifer is below the water level of either source.
Highly saline water from the secondary artesian aquifer was observed
in samples from two wells. One well (007-535-334a), shown in figure 5


Figure 5. Map of Econfina basin area showing location of data-collection points
referenced in report.

is 76 feet deep and the water contained 1280 ppm chloride. The other
well (008-545-224, fig. 5) is 101 feet deep and the water contained





REPORT OF INVESTIGATIONS NO. 41


1090 ppm chloride. Both of these are adjacent to saline surface-water
bodies. Wells penetrating the underlying Floridan aquifer, at and
near these locations, produce water low in chloride. The saline water
is presumed, therefore, to have leaked from the bays through the
water-table aquifer.
Apparently, the aquiclude overlying the Floridan aquifer (fig. 3)
in the coastal and bay area is sufficiently impermeable to prevent
leakage of water from the overlying aquifers. The occurrence of
chloride in water in the Floridan aquifer does not appear to be
related to areas of high chloride in water in the overlying sediments
or to the bays. Water levels in the Floridan aquifer have been lowered
below water levels in both the water-table aquifer and the secondary
artesian aquifer, by pumping in the major well fields. Extended periods
of low water levels in the Floridan aquifer have not resulted in an
increase in the chloride concentration of water from this aquifer as
would be expected if the aquiclude were leaking.
The chloride content of the water increases southwestward, the
general direction of water movement. The fresh water apparently
mixes with saline water in the aquifer to account for the increase in
chloride. Figure 6 shows the relation of the increase in total mineral


400
z
_J
2300
Only those samples containing greater
than 5 ppm chloride included **'







0 100 200 300 400 500 600 700 800 900
MINERAL CONTENT, IN PARTS PER MILLION
Figure 6. Scatter diagram showing relation of chloride to total mineral content
of water from the Floridan aquifer in the Econfina Creek basin area.


concentration of the water to the increase in chloride for all samples

Figure 7 is a block diagram of a section along the coast showing
chloride concentrations and water producing intervals of wells pene-
chloride concentrations and water producing intervals of wells pene-







FLORIDA GEOLOGICAL SURVEY


Chloride, in ppm


S Top of the Floridon Aquifer


250- Dissolved solids in ports per million
teodapl from Toe anid Shamplne, 1994)
275
Well (number indicates dissolved solids in ppm)
Figure 7. Block diagram of Econfina Creek basin showing areal distribution of
mineral content and chloride concentration in water from selected wells in the
Floridan aquifer.






REPORT OF INVESTIGATIONS No. 41


treating the Floridan aquifer. The chloride concentration generally
increases with depth into the aquifer. No chloride mineral is present
in the rock-forming materials and if water is not leaking from the
overlying rocks, then this saline water must be residual water that
remains in the rocks from a time when they were in contact with the
sea. The geologic history (Foster, in preparation) indicates this may
have happened many times. The residual water in the rocks would be
from sea water and chemically would probably differ little from
present sea water.
Records of chloride content in water from four wells, from 1950 to
1963, are given in figure 8. Although there is considerable variation




350 350

300" 47ff. d \e 00
00 4 ft. de .p



2 -00 0 537-332 0'- 3oo
.3 f. 1o3
F G of -i on-en ratio in water f.-" sel td wls
'".' "''". -*,.,' i\ .' 1 .\ ./\ / \.. o o ;-3 .-2 .. .
id\\ \ .- \ / IH2APfL-. 12Z
U 0oo- I.' I

30- 10

a0 30 1 1951 13 1953 1 534 I2SI S 1 12537 1952 I2260 2002 0Z62 190i 0

Figure 8. Graphs of chloride concentration in water from selected wells in the
Floridan aquifer.

in the chloride concentration, there appears to be no long-term trends
due to pumping.


STREAMFLOW

In using a stream, two quantitative aspects to be considered are
channel storage and the rate of flow. Channel storage is important in
considering uses such as boating, fishing, and other recreational activi-
ties. The rate of flow must be considered when determining the quan-
tities of water that can be withdrawn from the stream at any time.
Only the larger streams in the Econfina Creek basin have enough







FLORIDA GEOLOGICAL SURVEY


channel storage during periods of low water to be used for boating.
Most of the streams have sufficient flow to be a potential water sup-
ply. During periods of minimum flows there is more than 10 times as
much fresh water flowing into the bays than is being withdrawn from
all sources in the Panama City area.
Streamflow in the basin comes from several sources. During and
immediately following rains water flows directly into the streams as
overland flow. Between rains the streams receive only water that seeps
from the shallow sands and from artesian spring flow from the lime-
stone formations. Every stream receives seepage from the shallow
sands.
Streamflow to the bays is at an average rate of about 960 mgd
which amounts to 40 percent of the average rainfall. About 650 mgd
flows through Deer Point Lake into North Bay from Econfina Creek,
Bear Creek, Big Cedar Creek, and Bayou George Creek. Another 30
mgd flows into North Bay below Deer Point Dam from smaller
streams. West Bay receives a flow of about 70 mgd from Burnt Mill
Creek, Big Crooked Creek and smaller tributaries. East Bay gets
about 210 mgd from Wetappo Creek, Sandy Creek, Calloway Creek,
and smaller streams.
Figure 2 shows values of runoff from areas within the Econfina
Creek basin. It can be seen from this map that the physiographic fea-
tures affect runoff. The low runoff in the southern half of the basin
results from the poor drainage of the flat-woods forest. Drainage in the
sinks and lakes division is mostly internal and there is almost no
surface runoff. High base flow due to seepage from the porous sands
causes the high runoff in the sand hills division. The extremely high
runoff of 90 inches from the lower half of Econfina Creek is a result
of the artesian spring flow.


TABLE 1. Drainage areas, average flows, and low flows
of subbasins within the Econfina Creek basin.

Drainage area Average flow Low flow
Creek basin sq. mi. mgd mgd
Econfina Creek --.....--..........................-.... 129 355 226
Bear Creek .-------------.......... ........... ............... 128 226 52.
Wetappo Creek ---...-.....-..................... ... --77 80 6
Sandy Creek ---------..................... ...... 60 70 10
Bayou George Creek ..---.......---...-- ... 51 26 3
Burnt Mill Creek ---......... ................. 45 23 8
Big Crooked Creek .-...--.. ..-..--....-....-----.. 22 17 6
Big Cedar Creek -............ --....-. ....- -- 62 12 4
Calloway Creek ...................._. __._.._.. .. 13 9 .6
All others ...................-.......-... ..... 142






REPORT OF INVESTIGATIONS NO. 41


Stream data are given in table 1. The values of streamflow, except
those for Econfina Creek, are estimated from short-term continuous
discharge records or from periodic discharge measurements. The low
flow of a stream without storage reservoirs limits its use. Much more
water can be taken from streams if storage reservoirs are available
from which to draw during periods of extreme low flows.
The flow chart in figure 9 shows the streamflow pattern of the
basin. The average flow of Econfina Creek is 355 mgd, by far the
largest of all the streams. This is a runoff of 58 inches per year and is


Figure 9. Flow chart of streams in the Econfina Creek basin.






FLORIDA GEOLOGICAL SURVEY


about equal to the annual rainfall on the drainage area of 129 square
miles. Streamflow records have been collected since 1936 at Porter
Bridge near Bennett at a point where the drainage area is 122 square
miles.
The average flow of Econfina Creek from the upper half of the
basin is 90 mgd, only one-fourth of the flow from the entire basin.
Upstream from Tenmile Creek (fig. 1) the flow during dry periods is
seepage from the shallow sands. Downstream from Tenmile Creek
artesian springs contribute most of the dry-weather flow. The mini-
mum flow from the entire drainage area of Econfina Creek is about
210 mgd, or seven times the minimum flow of about 30 mgd from the
upper half of the drainage area.
Floods occur on Econfina Creek almost every year. The creek has
overflowed its banks at least once each year in all but six of the last
28 years. The longest period that it has stayed within its banks is the
3-year period August 1950 to September 1953.
Bear Creek is the second largest creek in the basin and has an
average flow of 226 mgd. It drains almost entirely from the sand hills
and flow is supported by seepage from these sands.
The average total surface flow into the bays was estimated as
960 mgd. Econfina Creek and Bear Creek contribute 581 mgd of this
flow. The remainder of the average flow (379 mgd) comes from the
smaller streams in the basin. The larger streams are listed in table 1.


STORAGE
Rainfall, although it varies, supplies an adequate amount of water
to the basin. Water held in storage in lakes and aquifers eliminates
frequent shortages which would result from the inconsistent rainfall.

LAKES
There are about 80 named lakes in the basin. Most of the lakes
are in southeastern Washington County. Deer Point Lake (see p. 87),
a fresh-water reservoir covering 4,700 acres in Bay County, is the
largest. Porter Lake in Washington County has a surface area of 930
acres and is the largest natural lake.
The natural lakes have not been developed for water use to any
great extent although they offer considerable potential as recreational
facilities. Wide fluctuations in most lake levels, caused by seepage
losses to the ground and variations in rainfall, discourage their devel-
opment. The Washington County Development Authority has pro-






REPORT OF INVESTIGATIONS No. 41


posed a plan to divert water from Econfina Creek to a group of lakes
known as The Deadening (see p. 73) and thereby stabilize their levels.
This plan, if executed, would add about 4,000 acres to the normal size
of this group of lakes.

AQUIFERS
The three aquifers the water-table aquifer, the secondary arte-
sian aquifer, and the Floridan aquifer store large quantities of
water. The portion of rainfall that enters these aquifers through down-
ward percolation is stored temporarily.
Water contained in the water-table aquifer discharges slowly by
downward percolation to the underlying aquifers and to the streams
and lakes through seepage and small springs. The water-table aqui-
fer, in the basin, is composed of fine to coarse sand and contains a
volume of water approximately one-fourth the volume of the saturated
section. The fluctuation of water levels in the water-table aquifer is
an indication of the change in storage, shown in figure 10. During dry
periods the water levels decline as the aquifer discharges the water
from storage. In wet periods water levels rise as more water is received
by the aquifer than is discharged.
Exclusive of flow from the artesian aquifer, the low flows of the
streams are maintained by seepage from the water-table aquifer and



Z
jU 4
--.I n



0 o \/ Well 023-532=124,
S312 at Bennett

_j 0.
z_6

< .2
z MIJ JAIS IOINID JIFIMIA IM JJ AASOND
1962 1963
Figure 410. Graphs of water level in the water-table aquifer and rainfall near
Bennett for part of 1962 and 1963.







FLORIDA GEOLOGICAL SURVEY


are indications of the size and ability of the water-table aquifer to
store and transmit water. Figure 11 is a graph of streamflow of Econ-
fina Creek near Compass Lake for the period April 1 to May 7, 1963.
S i i i I i i I i I i I i i i i I i i i i i i i I I I Ii i I




30r
30 i















APRIL 1963 MAY
Figure 11. Graph of streamflow of Econfina Creek near Compass Lake for the
period April 1 to May 7, 1963.
The low-flow portion of this graph represents seepage from the water-
table aquifer. The nearly flat slope of the low-flow portion of this
graph, such as that immediately preceding the rise of April 30, shows
that storage of water in the aquifer is sufficient to maintain the low
flow for long periods of no rainfall.
The secondary artesian aquifer which is present along the Gulf
coast also provides for storage of water in the basin. This aquifer is
saturated at all times, therefore the volume of water stored in it does
not change. Water discharges from this aquifer to the Gulf and to
wells. There is some exchange of water between this secondary arte-
sian aquifer and the aquifers above and below.
The Floridan aquifer is the most extensive aquifer in the basin and
the one from which most water is obtained. A more detailed study
was made of the characteristics of this aquifer.
AQUIFER CHARACTERISTICS
Certain hydraulic features of aquifers are of prime importance to
water-supply planners and developers. These hydraulic features, ob-








REPORT OF INVESTIGATIONS No. 41


trained from well data, should be determined before the first well field
is developed. A thorough knowledge of the hydraulics of an aquifer will
enable the planners to predict how much water the aquifer will supply.
In the design of a well field the planner should know how much water
he can expect to pump from each well without overdrawing the aqui-
fer; what the optimum spacing of wells should be to keep pumping
interference between wells to a minimum; what the design of each
well should be as to the diameter, depth of casing, length and setting
for screens or depths of open hole in a consolidated rock aquifer; and
the required pump specifications.
The water in an artesian aquifer is under pressure much the same
as water in a pipe leading from an elevated water tank, as shown in
figure 12. The piezometric (pressure) surface in an artesian aquifer


100


-I
W
> 75
-I



. .50
ULJ
w


UJ
0

200
I-
L&J
LU
IJ-
W

z 150

0
g loo
UJ
I-
100
-j
wi


Figure '12. Sketch showing similarity of an artesian pressure system and water
pressure developed by an elevated tank.







FLORIDA GEOLOGICAL SURVEY


is the level to which water will rise in cased wells drilled into the
aquifer, and is likened to the level of water in a vertical pipe that taps
a city water main. Water can be taken from an artesian aquifer and
the piezometric surface lowered without dewatering the aquifer. Only
when the piezometric surface is lowered below the top of the aquifer
is the aquifer dewatered. The quantity of water that can be withdrawn
without dewatering the aquifer depends upon the ability of the aquifer
to transmit water and the rate of recharge to the aquifer.

HYDRAULICS OF AQUIFERS
When a well that taps the Floridan aquifer begins to discharge
water, the piezometric surface surrounding the well is lowered. A cone,
centered at the discharging well, describes the shape of the lowered
pressure surface in the vicinity of the well. This lowered pressure sur-
face near a well or a group of wells in a producing field is referred to
as the cone of depression or cone of influence. This cone of depression
is graphically portrayed by the cones developed in the piezometric
surface of the Floridan aquifer in the vicinity of the well fields in the
Panama City area, as shown in figure 13.
In the initial stages of development the cone of depression is small
in diameter and depth. As discharge from the well continues the cone
spreads out. The lowering or drawdown of the pressure surface at the
well continues until the amount of water being discharged is balanced
by an equal amount being transmitted through the aquifer to the well.
This balance can be achieved by a decrease in natural discharge or an
increase in natural recharge.
When pumping stops the pressure surface begins to recover, rap-
idly at first, then at a progressively slower rate. With no further pump-
ing in the vicinity the pressure surface will eventually recover to the
initial level.
The response of an aquifer to pumping from one well or a group of
neighboring wells in terms of the rate and extent of drawdown in the
pressure surface, and the quantity of water that the aquifer will pro-
duce is related to the hydraulics of the aquifer at that location. The
principal hydraulic properties of an aquifer are its ability to transmit
and to store water.
An artesian aquifer, such as the Floridan aquifer in the Econfina
Creek basin, functions as a conduit through which water moves from
the areas of recharge to the areas of discharge. The aquifer's ability
to transmit water is expressed in terms of its coefficient of transmissi-
bility. It is the quantity of water, in gallons per day, that will flow






REPORT OF INVESTIGATIONS NO. 41


i 1 '/

!. I i I
Figure 13. Map showing the piezometric surface of the Floridan aquifer in the
Econfina Creek basin area, October 1962.
through a vertical section of the aquifer one foot wide and extending
the full height of the aquifer, under a unit hydraulic gradient, at the
prevailing temperature of the water.
The coefficient of storage of an aquifer is the volume of water re-
leased from or taken into storage per unit surface area of the aquifer







FLORIDA GEOLOGICAL SURVEY


per unit change in head normal to that surface. This storage coefficient
for an artesian aquifer is a measure of the small amount of water re-
leased or taken into storage when the aquifer compresses or expands
due to changes in water pressure.

AQUIFER TESTS
The coefficients of transmissibility and storage are determined by
the analysis of data obtained by aquifer tests or pumping tests. Three
aquifer tests were carried out during the field investigation of the
Econfina Creek basin utilizing available wells in the Floridan aquifer.
In each of the three tests conducted, a well was pumped at a constant
rate while water levels were measured in the pumped well and in one
observation well.
A test of short duration was run at Bid-a-wee (fig. 5) using a
standby supply well and an observation well belonging to the city of
West Panama City Beach. The pump was operated for a period of 6
hours at a rate of 55 gpm (gallons per minute). The rate of drawdown
and the rate of recovery of the water level were measured in the obser-
vation well, 49 feet from the pumped well.
A similar test was made at Long Beach (fig. 5) in which one well
was pumped for a period of 5 hours at a rate of 328 gpm. In this test
the observation well was 1,800 feet from the pumped well.
The third test was made at the Lansing Smith Steam Plant (fig. 5)
northwest of Lynn Haven. In this test one well was pumped at a rate
of 504 gpm for a period of 50 hours. The observation well was 1,195
feet away.
The Theis graphical method (Theis, 1935) was used to compute
values of T (coefficient of transmissibility) and S (coefficient of stor-
age) from the test data. The following values of T and S were
computed:
Bid-a-wee test T= 2,000 gpd/ft
S=1.2X 10-4
Long Beach test T= 4,000 gpd/ft
S=5 X10-4
Lansing Smith Steam Plant test T= 30,000 gpd/ft
S=3X10-4
These computations are based on the assumptions that the aquifer
is (1) of uniform thickness; (2) of infinite areal extent; and (3) homo-
geneous and isotropic (transmits water equally in all directions). De-
terminations of T and S from data collected during these three tests
give a wide range of values and show considerable change in the hy-






REPORT OF INVESTIGATIONS NO. 41


draulic character of that part of the aquifer penetrated by the wells
at each of the test site locations. The wells used in the tests pene-
trated the upper 330 feet of the aquifer at Bid-a-wee, 245 feet at Long
Beach and about 250 feet at the Lansing Smith Steam Plant. None of
the wells used in these tests penetrated the full thickness of the aqui-
fer. Deeper wells would draw water from a greater thickness of the
aquifer and would, consequently, give higher values.
The values of the coefficient of storage from these tests are con-
sistent with values for the Floridan aquifer in other areas. The co-
efficient of transmissibility of the aquifer at the Lansing Smith Steam
Plant is higher than at the other test sites. This may indicate vertical
leakage into the aquifer from the overlying formations. Because the
tests show considerable differences in the coefficient of transmissi-
bility of the aquifer within the bay area, the coefficient of transmissi-
bility determined from pumping tests nearest a proposed well field
should be used. Additional tests should be made at distant locations
before a well field is designed.
In order to predict the amount and areal extent of drawdowns that
will result from different rates of pumping and different well spacings,
computations were made using the Theis formula (Theis, 1935) and
the coefficients of transmissibility and storage determined at the
Lansing Smith Steam Plant, at Bid-a-wee, and at Long Beach. Figure
14 shows theoretical drawdowns in the vicinity of a well discharging
at a constant rate for different lengths of time at the Lansing Smith
Steam Plant, the Long Beach, and the Bid-a-wee locations. These
drawdowns represent the conditions that would result from continuous
pumping at this rate. Because drawdowns vary directly with dis-
charge, drawdowns for greater or lesser rates of discharge can be com-
puted from these curves. For example, the drawdown 100 feet from
a well at the Lansing Smith Steam Plant discharging at 500 gpm
would be 24 feet after 100 days of pumping. If the well had discharged
at 100 gpm for the same length of time, the drawdown at the same
distance would have been only one-fifth as much, or about 5 feet.
The graph of drawdowns along a line of 10 wells, spaced 2,000 feet
apart, at a rate of 200 gpm, are shown in figure 15. The values used
to determine this profile were obtained by summing the overlapping
drawdowns for each well in the line as read from the 100-day curve for
the Long Beach test (fig. 14). Similar graphs can be computed to de-
termine the drawdown that would result from different pumping rates
or different well spacings (Lang, 1961, Theis, 1957).
The cone of depression in the vicinity of a well or a well field
being pumped at a constant rate will eventually stabilize if a balance







FLORIDA GEOLOGICAL SURVEY


DISTANCE, IN FEET, FROM DISCHARGING WELL


Figure 14. Graphs showing theoretical drawdowns in the vicinity of wells being
pumped at a constant rate for selected periods.






REPORT OF INVESTIGATIONS NO. 41


THOUSANDS OF FEET
25 20 15 10 5 0 5 10 15 20 25


50 ---.
It-
UW 100 -- -- -- -

150 - -
Computations based o /

200 T= 4,000gpd/ft.
S= .0005

250 __
Figure 15. Theoretical drawdowns along a line of 10 wells after 100 days of
pumping at a rate of 200 gallons per minute at each well.

is established between the amount being pumped and the amount
moving to the well, either through a decrease in natural discharge or
an increase in natural recharge. Water-level records (p. 33) in the
well field of the International Paper Company show that the cone of
depression in that well field had stabilized by 1951 as a result of
controlled pumping.
WATER USE
Water planners should know how much of the available water is
being used and the areas from which it is taken. Oftentimes, the
amount of water available in an aquifer is ascertained by determining
how much is being withdrawn and by measuring the effects of this
withdrawal on the water levels in the aquifer. For example, the low
water levels in the Floridan aquifer prior to February 1964 were near
the level where dewatering of the aquifer would begin near the cen-
ters of heavy pumping.
The major uses of water within the Econfina Creek basin are rec-
reation, manufacture of paper products, and public and domestic sup-
plies. An undetermined though relatively small amount is used for
irrigation. More than 80 named lakes, inland bays that cover over 100
square miles, and the larger streams are used for recreation.
Information was collected on the various municipal and industrial
uses of water within the basin, except recreation, in order to estimate
the total amount being withdrawn. Data on principal water-supply
systems are given in table 2.











'I'TAIL 2. I4tcnrli of watclr ipply l .ysntriIM in tihe Ic('onflna (Crwk Blasin arau.


Aquifer: F, Floridan; W, wator table.

Treatment: A, aeration; C, coagulation; CI, chlorination;


Number
of wells


Well-pump Ground Elevated
Aquifer capacity storage storage
(gpm) (gallons) (gallons)


F, floculation; I1, recarlonation;
S, softening; St, stabilization.


Capacity of
stand by
Treatment well pump
(gpm)


Yearly pumpage
(mhlliona of
gallons)


Remarks


Panama City:
St. Andrew Plant



Millville Plant

Lynn Haven

West Panama City Beach
Long Beach
Tyndall Air Force Base


U. S. Navy Mine Def. Lab.
Woodlawn Subdivision
Hathaway Water System
Mexico Beach Water System
Gulf Power Co. Water Plant
International Paper Co.


8 F 285 to 500 1,000,000 300,000 A, St, CI, 8


430 to 500
e175
750
700
500
328
300 to 600


300
e350
60 to 100
735
00
)50 to 776


400,000

100,000

1 reservoir


240,000
125,000
84,000
45,000
20,000
100,000
250,000


100,000

250,000
100,000
500,000
160,000
50,000



100,000
400,000


A, St. CI, fS
A, St, Cl, S
A, C1

A, Cl
Cl
A, C, R, CI, F, S
St

A, CI, St
A, C1
CI
A, Cl


800 866.8 Ground storage 2 tanks
W00,000 each,
Elevated storage for
Panama City system 3
tanks 100,000 gal, ea.


600


360
500.
328
1,500


630
e350


735


660.2

95.5

84.9
76.1
1,017


78
31.6
12.7
24.4


5,478.5
5,478.5


2 tanks 350 each



2 tanks 250,000 each


2 tanks 42,000 each


4 tanks 5,000 each


Not in operation
As of Jan. 31, 1964
began receiving water
from Deer Point Lake


e Estimated


Location


____ _I_ _I~ 1 __





REPORT OF INVESTIGATIONS No. 41


Prior to February 1964, no surface water was being withdrawn and
ground water was being used at the rate of 25.2 mgd. Of this amount,
22.7 mgd came from the Floridan aquifer. In February 1964, when
the International Paper Company began using surface water, ground-
water use in the basin was reduced to about 11 mgd.
The International Paper Company, the major industry in the
area, is the largest user of water. Prior to February 1964, the water
used by this company was supplied by wells. About 13.5 of 15 mgd
was pumped from the Floridan aquifer and the remainder was pumped
from the watertable aquifer. Water used by this industry prior to 1964
is shown by graph in figure 16. In February 1964, this company started
receiving water from Deer Point Lake at the rate of about 30 mgd.
There are nine public water-supply systems in the area. All water
produced by public water-supply systems is pumped from the ground.
The rate of pumping varies from 6.7 mgd during low demand periods
of fall and winter to 12.9 mgd during peak demand periods of spring
and summer. Areas served by these systems and locations of the wells
are shown in figure 17.
Water use has increased with population (fig. 16). Also the per
capital consumption in Panama City has increased from 70 gpd (gal-
lons per day) to 80 gpd during the 10-year period, 1950-60. This
figure is based on the average daily pumpage of the Panama City
water system and the population of the area supplied by this system.
Only a small part of the water pumped by the city is supplied to indus-
try and other non-domestic users. Also, there are a number of private
irrigation wells in the city. Partly for these reasons the per capital con-
sumption is below the more normal rate of about 150 gpd per person
that is reported in other areas.
Nearly 18,000 persons live in areas not served by public water
systems. At a per capital consumption of 80 gpd this would amount to
about 1.4 mgd used for rural domestic purposes.


WATER HIGH LIGHTS OF THE BASIN
DECLINE OF WATER LEVELS IN THE PANAMA CITY AREA
GENERAL STATEMENT
From 1908 to 1964 water levels in the Floridan aquifer near Pan-
ama City were lowered about 200 feet in the centers of major well
fields. This decline represents the difference between the reported
static water level of 16 feet above mean sea level in the first well
drilled in 1908 and the pumping water levels in the major well fields







30 FLORIDA GEOLOGICAL SURVEY

a "O O i I a i I I i i I I I i i I \


INTERNATIONAL
i i I i i 5 I I I i I i
i i I I I I I '



PAPER COMPANY I I I I




I I I I I i I I

0 4POo-

I
1 ; I j




O I Ii r 'iI II
I I J I I l l

0
I I I I I I ,









. OO I .



40,000- IiiANAI IM A i ION
z IIr I I I ,.



















Figure 16 Graphs of water use and population in the Panama Cit area.
I I l
l I I i i I
,w I i ,i I I
m I [ j I I s I
g 6 p f ,t s a p ain in i I ana I l rea.






Figur 16 rpso ae s n ouaini h aaaCt ra





REPORT OF INVESTIGATIONS No. 41


Figure 17. Map of the Panama City area showing the location of water wells
for each water system and the area supplied by these systems.

in early 1964. In January 1964 one well field consisting of 21 wells
was shut down. The water levels in this well field recovered 163 feet
within 51 days. Figure 18 shows the approximate piezometric surface
in 1908 under natural water conditions. The piezometric surface in
1962 (fig. 13) shows the lowered water levels caused by pumping
since 1908.

HISTORY OF GROUND-WATER DEVELOPMENT
The first deep well reported in the Econfina Creek basin was com-
pleted in 1908 for an ice plant in downtown Panama City (Sellards,
1912). In 1909 Panama City drilled a city supply well at the location
of the old National Guard Armory. In the same year another well was
drilled near the present water tank on Eleventh Street to supply
St. Andrew.






FLORIDA GEOLOGICAL SURVEY


Figure 18. Map showing the approximate piezometric surface of the Floridan
aquifer in the Panama City area in 1908.

From 1908 to 1930 there was not enough water withdrawn by
pumping to noticeably affect water levels in the Floridan aquifer.
However, in 1930 the International Paper Company developed a well
field in the Millville area, consisting of seven wells in the Floridan
aquifer and three wells in the water-table aquifer. Three of these wells
in the Floridan aquifer flowed at the time of drilling and the static
levels in the others were about 20 feet above mean sea level (from 8
to 20 feet below land surface). The original test well for this supply
reportedly flowed at a rate of 60 gpm and, when pumped at a rate of
700 gpm, the water level dropped to 55 feet below land surface. A cone
of depression developed in the piezometric surface of the Floridan
aquifer as water was withdrawn. Static water levels in wells drilled
in 1935 were more than 50 feet lower than in the original wells drilled
in 1930. By 1937 the water level near the center of the well field re-
portedly was 104 feet below mean sea level, a decline of 124 feet from
the time pumping began. This cone of depression expanded as the
paper company extended their well field eastward and northward.
A program was initiated by the paper company to protect their
water supply. Four wells near the original center of pumping were





REPORT OF INVESTIGATIONS NO. 41


abandoned to decentralize pumping and to thus prevent excessive
drawdowns which were limiting production of water. The control of
water levels was considered necessary also as a precaution against
salt-water encroachment. Pumping from each of the other wells in the
field was regulated for the most efficient production from the aquifer
within the cone of influence. Water-level records, shown in figure 19,
of an abandoned well about one mile from the center of pumping show
the effectiveness of this program.

-J
W 75
Water level affected by
80- near-by pumping wells
J
-85-
S90-
S95
M 100-

U I
w 105A





<125 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963

Figure 19. Graph of water levels in observation well 008-537-332 near the center
of the International Paper Company well field for the period 1951 to 1963.

In January 1964 the paper company was producing water from 21
wells in the Floridan aquifer and 10 wells in the water-table aquifer.
These wells were pumping an average of 15 mgd, of which about 13.5
mgd were from the Floridan aquifer. At this time the water level in
the Floridan aquifer under pumping conditions was about 184 feet
below mean sea level at the center of pumping and 100 feet below
mean sea level on the east edge of the field. These represent draw-
downs of about 200 to 120 feet since pumping began in 1930. Although
this is a considerable drawdown, the pumping level in the field was
essentially stabilized at this level. Minor fluctuations (fig. 19) were
caused in part by seasonal variations in pumping from neighboring
well fields. The major recoveries shown on this graph indicate periods
when pumping from wells near the observation well was stopped tem-
porarily or when pumping from the entire field was stopped.







FLORIDA GEOLOGICAL SURVEY


At the end of January 1964 when the paper company began using
water from Deer Point Lake, all of the wells that had been pumping
from the Floridan aquifer were shut down. In four days water levels
in the aquifer recovered from about 200 to 83 feet below mean sea
level near the old center of pumping and from 105 to 58 feet below
mean sea level on the east edge of the field. After 51 days, water levels
had recovered to 21 feet below mean sea level near the center and to
about mean sea level on the east edge of the field.
In 1936 Panama City built a water plant in the Millville area.
This plant was initially supplied by wells in the water-table aquifer,
but later supplied by wells drilled into the Floridan aquifer. In 1955
a well drilled into the Floridan aquifer had a water level of 63 feet
below mean sea level. In October 1962, after all pumps were shut off
for a period of 6 hours, the water level in this well was 72 feet below
mean sea level, a net decline of 9 feet from 1955 when the well was
drilled. The decline in water levels is attributed to pumping from this
well field and from the nearby paper company well field.
Another public water-supply system for Panama City was con-
structed in the St. Andrew section during late 1942 and 1943. When
the first of the original seven wells were drilled the water level in the
Floridan aquifer stood at about mean sea level. By mid-1943, when
the last of the seven wells was drilled, pumping from the first wells
had lowered the water level in the vicinity about 20 feet. In October
1954, when an eighth well was added to the well field, the pumping
level had been lowered to 67 feet below mean sea level. This drawdown
of 67 feet resulted from pumping at an average rate of 1.6 mgd.
Measurements of water-level in the St. Andrew well field in Octo-
ber 1962, after a 6-hour recovery from pumping, showed the water
level to be 87 feet below mean sea level near the center of the field.
The additional drawdown of 20 feet in the center of the field during
the 9-year period from 1954 to 1962 represents the effect of pumping
at 2.0 mgd, an increase of 0.4 mgd in the average daily pumping rate.
A well field consisting of four gravel-packed, screened wells in the
water-table aquifer was constructed at Tyndall Air Force Base in
1941 to supply water for the base, then under construction. It was
found that this aquifer would not supply sufficient water so it became
necessary to develop a supply from the Floridan aquifer. When the
wells were drilled in the Floridan aquifer the water level stood about
8 feet above mean sea level. By 1946 the water level had lowered to
about 10 feet below mean sea level. In 1961 pumping levels in the
Floridan aquifer were as much as 82 feet below mean sea level near






REPORT OF INVESTIGATIONS No. 41


the center of the well field. The cone of depression which had been
developing in this field was clearly established by 1961.
The maps of the Panama City area showing the piezometric sur-
face of the Floridan aquifer, figures 13, 18, and 20, illustrate the effect
of development of water from this aquifer. The piezometric surface in
1908 (fig. 18) is indicative of the general conditions in the area up to
about 1930. By 1947 the 4 principal well fields were producing enough
water to develop sizeable cones of depression in the piezometric sur-


Figure 20. Map showing the piezometric surface of the Floridan aquifer in the
Panama City area in April 1947.

face (fig. 20). A comparison 6f piezometric surfaces in figures 13 and
20 clearly shows that increased pumping from expanded well fields
has extended the cones of depression and has lowered water levels
generally throughout the Panama City area during the period from
1947 to 1962.
THE DEADENING LAKES
The Deadening is a group of lakes in the lower end of a closed
creek basin-'in the southeastern corner of Washington County, as
shown in figure 21. These lakes receive the surface drainage from the








FLORIDA GEOLOGICAL SURVEY


053a


Figure 21. Map of White Oak Creek basin in southeastern Washington County
showing The Deadening area.

White Oak Creek basin of 44 square miles and seepage from the water-
table aquifer which underlies the surrounding sand hills. They lose
water only by evapotranspiration and percolation to the underlying
limestone formation. Gully Pond, Wages Pond, Hamlin Pond, Still
Pond, and Hammock Lake are joined at an elevation of 70 feet and
their combined surfaces cover 3,640 acres. Porter Lake is connected
to the other lakes at high water through Swindle Swamp and Black
Slough. At an elevation of 70 feet, Porter Lake covers 930 acres. The






REPORT OF INVESTIGATIONS No. 41


area of these lakes and Swindle Swamp is about 5,000 acres at an
elevation of 70 feet.
The variances in the supply of water and the constant drain
through the ground cause wide fluctuations in stages of The Dead-
ening lakes. In 1950, as a result of flood waters, the lakes reached an
elevation of about 70 feet. Due to the dry weather for a period of
several years (fig. 4) some of the lakes were dry and others had re-
ceded to elevations as low as 40 feet by 1956. Above average rains in
the late 1950's caused some of the lakes to recover to normal levels.
Since 1960 lake levels have again receded.
The Deadening lakes have a considerable recreation potential.
However, the wide ranges in lake levels prevent the potential from
being realized.
The Washington County Development Authority has proposed a
plan to divert water from Econfina Creek to these lakes at the rate
necessary to stabilize them at an elevation of 70 feet above mean sea
level. The diversion from Econfina Creek would be at a point just
downstream from Tenmile Creek, by way of a diversion canal to
Porter Lake. After Porter Lake is filled, water would overflow through
Swindle Swamp and Black Slouth to The Deadening lakes.

GEOLOGIC AND HYDROLOGIC SETTING
The Deadening lakes are located in the sinks and lake physio-
graphic division (fig. 2). They originated by the collapse of the over-
lying sands and clays into cavities caused by solution of the limestone
of the Floridan aquifer. Where solution and collapse activity has
breached the confining layer, figure 22, there is a loss of water from
the lakes to the Floridan aquifer.

WATER LEVELS
Levels of the Deadening lakes have been as high as 70 feet and as
low as about 40 feet above mean sea level. A topographic map made in
1950 shows an elevation of 70 feet for Porter Lake, and shows the
Deadening lakes to be completely covered with water at an elevation
of 69 feet. Based on flood marks, about 70 feet is the highest elevation
that the lakes have reached. The bottoms of Hammock Lake and
Porter Lake are at an elevation of about 40 feet. Hammock Lake was
reported to have been dry in 1956.
Figure 23 shows that lake levels have varied from a high of 68.3
feet in Porter Lake to a low of 44.2 feet in Gully Pond during the
period from'1961 to 1963. Lake levels declined throughout most of
that period. In mid-1963 the lakes began responding to rainfall as







FLORIDA GEOLOGICAL SURVEY


3--4- -
I





southeastern Washington County.00






la, and the aquifers.-


Figure 22low Geohydrologic sections through the White Oak Creek enters Swindle Swamp and separates,
and ground-water levels indicates hydrologic continuity between the
lakes and the aquifers.
Flow from White Oak Creek enters Swindle Swamp and separates,
part going to Porter Lake and part going to Still Pond through Black
Slough (fig. 21). The flow from Still Pond is to Hamlin Pond by way
of subsurface channels. These subsurface channels are evidenced by
sink holes through which movement of water can be seen. Hamlin
Pond overflows to Hammock Lake. Wages Pond receives surface
drainage from Howard Swamp and overflows to Gully Pond. Ham-
mock Lake and Gully Pond are at a lower stage than the other lakes
because they receive surface flow only when the other lakes overflow.
A comparison of the recessions of lake levels to the expected evap-
orational losses indicates the lakes lose water to the underlying Flor-
idan aquifer. The level of Clarks Hole, an arm of Hamlin Pond,
receded seven feet from August to December 1962. Below a stage of
55 feet, Clarks Hole is separated from Hamlin Pond and the shore
line is below the line of vegetation, which eliminates most transpir-
ational losses. The major water losses from Clarks Hole below a stage
of 55 feet are evaporation and downward leakage. During the 5-month
period that water levels in Clarks Hole declined seven feet, the evap-
orational loss was about 2 feet, based on pan evaporation records







REPORT OF INVESTIGATIONS No. 41


1962


1963


SAMIJ Jd A SI 0 ND J F MIAM J J IAISIOINID

10-
S(2 miles north of Porter Lake)

6
4-
2-
0-


1962 1963


Figure 23. Graphs of water levels and rainfall in the vicinity of the Deadening
lakes.


70


_J
W 68


66
66


S62
w

60

w

0 58
m


56
I-
w
W
UJ.

LL 54

Z
52

.J
L 50
w
-J

48

IJ
46



44


1961


1961






FLORIDA GEOLOGICAL SURVEY


collected at Woodruff Dam by the U. S. Weather Bureau. The re-
maining five feet represents leakage to the ground. Clarks Hole re-
ceived no inflow during this period. Some of the other lakes did, which
minimizes the apparent losses shown by graphs in figure 23.
The Deadening area received about 11 inches of rain in July 1963,
of which 8 inches fell during the last 10 days of the month. These
heavy rains caused moderate rises in the lake levels and the piezo-
metric surface of the Floridan aquifer. The ground-water level and
lake levels, in general, showed about the same amount of rise, from
2 to 5 feet. The water level in Clarks Hole rose about 12 feet as a
result of overflow from Hamlin Pond.
Water in the Floridan aquifer moves in the general direction of the
slope of the piezometric surface (fig. 13). Water moves to the center
of The Deadening area from the northeast, and moves radially from
The Deadening area toward Econfina Creek to the southeast, the
Gulf of Mexico to the south, and Pine Log Creek to the southwest.
Wells in The Deadening area showed larger gains during the rise
of July 1963 than wells outside the area. This indicated that the
Floridan aquifer gains water indirectly from rainfall more rapidly in
The Deadening area than in the surrounding area.
Water diverted to The Deadening lakes would move from the
lakes to the Floridan aquifer at a rate proportional to the head
between the lake surfaces and the piezometric surface of the aquifer.
Raised lake levels could increase this head and cause more water to
enter the aquifer. If the lake levels are maintained at a constant ele-
vation, the head that will be established depends on the ability of the
Floridan aquifer to transmit water away from the area.

FLOW OF ECONFINA CREEK
Information on the flow of Econfina Creek was obtained to de-
termine the amount of water available at the proposed point of diver-
sion and to determine what effect diversion would have on streamflow.
The proposed point of diversion is just east of the north end of
Porter Lake, about midway of the basin. The drainage area of Econ-
fina Creek above the proposed point of diversion is about 67 square
miles. The average flow at this point was estimated to be 90 mgd.
Minimum flow at the point of diversion is the important criterion
in determining the available flow. The greatest amount of water will
be needed in the lakes when the creek flow is lowest. A minimum flow
of 30 mgd was estimated on the basis of three discharge measure-
ments and the relation of these measurements to the long-term flow
record at the Bennett gaging station. This minimum flow probably will





REPORT OF INVESTIGATIONS No. 41


not occur more often than once every 15 to 20 years, and then prob-
ably will not persist for more than a few months. A flow of 36 mgd
was measured at the point of diversion on May 27, 1963, during a
period of extreme low flow.
A dam to create a retention reservoir along Econfina Creek is being
considered. The main purpose of this reservoir would be to raise the
water level in the creek and make gravity flow to Porter Lake possible.
There would be a usable storage in this reservoir between elevations
80 and 95 feet of about 4,000 acre-feet. This amount of storage would
provide 10 mgd for a period of four months. This, added to the natural
flow of the creek, would assure a minimum flow of about 40 mgd. A
flow of 40 mgd would supply about 0.7 of a foot of water per month
on the 5,000-acre lake area.
If diversion from Econfina Creek is at a rate of 30 mgd, the stream-
flow just downstream from the point of diversion would be almost
depleted during periods of low flow. This effect will diminish down-
stream. Diversion of 30 mgd would reduce the flow below Gainer
Springs about 15 percent. The width of the stream at this point would
not be affected, and the depth would be reduced from a usual 4.5 feet
to about 4 feet. Figure 24 shows, pictorially, the effect on stream-
flow if 30 mgd were taken from the creek during low flow. A diversion
of this amount is a negligible part of the total flow into Deer Point
Lake and would have no adverse effect on this water supply.
Some of the diverted water would be returned to Econfina Creek
by an increase in the flow of artesian springs. The higher spring flow
would result from an increase in the piezometric slope caused by
recharge to the Floridan aquifer from the lakes.

SPRINGS
The artesian springs along Econfina Creek are located downstream
from a point just east of Porter Lake. Spring flow to the creek in-
creases downstream to a maximum near the Washington-Bay County
line. Below Gainer Springs it diminishes and there is little, if any,
spring flow to the creek below the gaging station near Bennett, as
shown on the flow chart in figure 25.
Spring water flows into Econfina Creek directly through the
stream bed, from the base of rock bluffs, and from short spring runs
about a quarter of a mile in length. The spring water emanates from
the Floridan aquifer where Econfina Creek has breached the over-
lying, confining clay layer. Figure 22 illustrates the hydrologic rela-
tionship of the aquifer with the creek. Figure 13 shows the pattern
of flow towards the springs.







FLORIDA GEOLOGICAL SURVEY


0 2 4 Wals


NO sPMI WSLIREAM FMW HItE




FLOW CHART
T~at width of stroem represents flow wilh no diversion.
30 mgd diverted
SStreamflow other 30 nO d diverted
4 Flow--moasing poit
0 400 rmg
Flow scale


Figure 24. Flow chart of Econfina Creek during the low-water period of May
1963 showing the effect on streamflow if 30 mgd were diverted at the proposed
dam site.


It was possible to make direct measurements of the flow from
Blue Springs and Williford Springs. Flow from Gainer Springs was
determined by the difference in streamflow measurements above and
below the group. Other spring flow, which could not be measured,
enters the creek along its bed and banks.
The amount of flow attributable to spring flow was calculated at
the Bennett gaging station utilizing electrical conductivity measure-
ments of the water. Pure water is a poor conductor of electricity but
mineral matter dissolved in water consists of charged particles which
will conduct an electrical current. The amount of current that a water
will conduct is an indicator of the amount of dissolved minerals in
the water. The measurement of the electrical current conducted by







REPORT OF INVESTIGATIONS No. 41


FLOW CHART
M Spring flow
E Non-spring flow
0 300mgd
Flow scale


1 0 1 2 3 4 5mi.

Figure 25. Flow chart of Econfina Creek showing spring flow.


water is expressed as specific conductance in units of micromhos.
The specific conductance of the water from the springs along
Econfina Creek ranged from 95 to 150 micromhos. Water in the creek
above the area of spring flow ranged from 14 to 26 micromhos. Aver-
age specific conductance values of 114 micromhos for spring water
and 20 micromhos for non-spring water were used in the calculation
of spring flow.
i /







FLORIDA GEOLOGICAL SURVEY


Water at the Bennett gaging station was considered to be a thor-
oughly mixed combination of spring water and non-spring water.
Flow at the Bennett gaging station, attributable to springs, was
calculated from the formula:

Kb K
Q K Qb
sK -K

where: Q is spring flow

Qb is streamflow at Bennett
K is specific conductance of spring water
K is specific conductance of non-spring water

Kb is specific conductance of the mixture

Figure 26 shows the flow of Econfina Creek during non-flood periods
and that portion attributable to springs for 1963. Spring flow con-
tributes about two-thirds of the total flow of Econfina Creek.


90C G800


730- 70TOO


600- TOTAL FLOW


00- -500





300 300
3iO
1





CALCULATED SPRING FLOW



oo .o


"AM FEDB UM APR MtI JUNE AI AU6 SEPT OCT NOV DEC
Figure 26. Graphs of streamflow, spring flow, and specific conductance for
Econfina Creek near Bennett in 1963.






REPORT OF INVESTIGATIONS No. 41


DEER POINT LAKE
Deer Point Lake (fig. 1) was formed on November 17, 1961, by
construction of a salt-water barrier across North Bay at Deer Point.
The lake was planned to serve as a source of fresh water and to pro-
vide recreational facilities. It covers 4,700 acres, most of which was
formerly a part of North Bay, and stores approximately 32,000 acre-
feet of water at a level of 4.5 feet above mean sea level, the elevation
of the dam.
The lake is stabilized at an elevation of 5.0 feet above mean sea
level. The potential fresh water supply is approximately 650 mgd,
the average flow through the lake to North Bay. In February 1964
the only withdrawal from Deer Point Lake was the 30 mgd by the
International Paper Company.
A study of the lake hydrology in the period immediately before
and for several months after the dam was constructed (Toler, Mus-
grove, and Foster, 1964) was made to determine the rate of freshen-
ing and the effect the lake would have on the water-table aquifer.
Figure 27 shows the rate of freshening of the lake in terms of the
number of times the inflow of fresh water would have filled the lake.
Plotted in this manner, the graph enables a prediction of the rate of
freshening of any similar lake if the volume and concentration of lake
water and inflowing water are known (Toler, Musgrove, and Foster,
1964). When the barrier was completed on November 17, 1961, the
lake was about half full and the chloride concentration was about
7,400 ppm. Flow over the spillway began on November 29, 1961, and
the chloride concentration had been reduced to 3,700 ppm. In mid-
February 1962 the chloride concentration was about 200 ppm.
When the barrier was completed, water levels in the lake and in
the water-table aquifer adjacent to the lake rose rapidly, as shown
in figure 28. An immediate effect of the rise in the lake level was to
reverse the water-table gradient near the lake so that water moved
from the lake into the aquifer. This is evidenced by the rise in chloride
content in water from well 015-535-232, 45 feet from the lake. Water
in wells 100 feet or more from the lake showed no change in chloride
content. When the water table adjusted to the new lake level, the
water movement was again toward the lake and the high chloride
water was flushed from the aquifer.

SUMMARY
In general, the hydrologic system through which water moves in
the Econfina Creek basin is similar to most basins in northwest
I







46 FLORIDA GEOLOGICAL SURVEY


1961 1962 1963
Di pC JAN FEB MAIAPR J' JUL AUG SPT OCT NOV DEC JAN



4500 -



4000 -



3500

z
2
S3000 Vi- volume of fresh woltr that has flowed into lake
I:slince spillway overflow begon

a" V volume of the lake at spillway elevation
a 2500
I-


. 2000


U 1 500



000 .



500 -



I 2 3 4 5 6 7 8 9 10 II 12 13 14 15 16 17 18 19 20 21
V, /V0
Figure 27. Graph showing the relation of chloride in water in Deer Point Lake
to fresh water inflow.


Florida. That is: (1) rainfall is the source of all the water even though
some falls outside the basin and moves into the basin underground;
(2) the surface materials are highly porous, unconsolidated sands;
(3) it is underlain by the artesian Floridan aquifer; and (4) water
leaves the basin by streamflow, evaporation, transpiration, under-
ground flow to the ocean and other basins, and by consumptive use.
There are four physiographic divisions within the basin that
affect the surface drainage and the water storage, both above and







REPORT OF INVESTIGATIONS No. 41


4.0 I Well 016-535-342b Z
Water level



2.0 3 000




Figure 28. Graphs showing the rise of water levels and change in chloride




content of ground water after construction of Deer Point Dam.


below the ground. These are the sand hills, sinks and lakes, the flat-
woods forest, and the coastal sand dunes and wave-cut bluffs.
The surface materials on which the physiographic features have
developed are generally very porous, permeable sands which are from
1.0 2000








0 1 feet thick. These sands form the water-table aquifer. A con-







fining layer, or aquiclude, of sandy clay and clayey shell material
NOV. DEC. JAN. FEB MAR. APR. MAY JUNE JULY AUa SEP. OCT. NOV. DEC. JAN. FEB& MAR. APR. MAY JUNE
961 1962 963





sepaFigure 28. Graphs showing water-table aquifer and the Floridand change in chloridefer.
In the bay area and along the gulf construction of Deer Point Dam.rtesian

aquifer. Here the foreground. These aretion that forms the aquiclude is thicker thflat-
woodit is to the north and is overlain and in part und wave-cutrlain bluff some shell-
The surface mat which contain water under arte physian pressure. Which feater pro-have
during zones in the shell-hashy very porous, permeable aquicludends which are termed
0 to 140 feet thick. These sands form the watertable aquifer. A con-
fining layer, or aquiclude, of sandy clay and clayey shell material



separates he Floridwater-table aquifer underlies the entire basin aquifbelow the aqui-
In the bay area and along the gulf coast there are two artesian



aquifer. HereIt is composedof limestone formation that forms the aquiclude thicker thanlower
it is to the north and is overlain and in part underlain by some shell-
hash beds which contain water under artesian pressure. Water pro-
ducing zones in the shell-hash beds above the aquiclude are termed
the secondary artesian aquifer.
The Floridan aquifer underlies the entire basin below the aqui-
elude. It is composed of limestone formations that include the lower
units of the shell-hash beds and are as much as 1,200 feet thick.
The basin receives an average of 58 inches of rainfall per year.
A partof the rainfall is absorbed by the porous surface sands and a
part moves directly into the streams. Some water from the sands
moves to the streams and maintains flow during periods of no rain-
(I






FLORIDA GEOLOGICAL SURVEY


fall. Water also moves from the sands downward to the Floridan
aquifer but the amount diminishes toward the southwest because the
aquiclude becomes thicker. Movement within the Floridan aquifer
is generally southward with some water flowing into the channel of
Econfina Creek by way of artesian springs.
The transmissibility of the Floridan aquifer varies within the
basin, and is lower than the transmissibility of this aquifer in most
other areas in Florida. Coefficients of transmissibility range from
2,000 to 30,000 gpd/ft.
The water in the lakes and streams differs little in mineral con-
centration from rain water because of the relative insolubility of the
surface materials. Two areas of exception are where Econfina Creek
receives artesian spring flow and near the mouth of streams that
empty into salt-water bays.
The mineral content of water from the water-table aquifer gener-
ally ranges from 10 to 50 ppm, and that of water from the secondary
artesian aquifer from 80 to 150 ppm. The mineral content of water
from the Floridan aquifer is higher than that from the other two
aquifers. Mineral concentrations in water from this aquifer show
increases in all constituents from the northern part of the basin to
the southwest.
Some salt-water intrusion was detected in the water-table and
the secondary artesian aquifers adjacent to the bays and Gulf. The
confining clay layer overlying the Floridan aquifer in the coastal
and bay area is sufficiently impermeable to prevent leakage of water
from the overlying aquifers. Water in the Floridan aquifer in the
southern part of the basin is apparently a mixture of fresh water and
residual saline water.
Streamflow to the bays is at an average rate of about 960 mgd
which for a year would amount to 40 percent of the average annual
rainfall of 58 inches. About 650 mgd flows through Deer Point Lake
into North Bay, and another 30 mgd flows into North Bay below Deer
Point Dam. East Bay receives a flow of about 210 mgd and West Bay
about 70 mgd. Most of the streams have sufficient flow to be a poten-
tial water supply. During periods of minimum flows there is more
than 10 times as much fresh water flowing into the bays than is being
withdrawn in the basin. Econfina Creek, by far the largest stream
in the basin, has an average flow of 355 mgd.
Low runoff from the southern part of the basin results from poor
drainage features of the flat-woods forest. Drainage in the sinks and
lakes division is mostly internal. High base flow due to seepage from
the porous sands causes high runoff in the sand hills division.






REPORT OF INVESTIGATIONS NO. 41


There are about 80 named lakes in the basin, most of which are
in southeastern Washington County. Deer Point Lake, a fresh-water
reservoir covering 4,700 acres, is the largest. Porter Lake has a sur-
face area of 930 acres and is the largest natural lake.
The major uses of water within the basin are for the manufacture
of paper products, for public and domestic supplies, and for recrea-
tion. Prior to February 1964 no surface water was being withdrawn
and ground water was being used at the rate of 25.2 mgd. Of this
amount, 22.7 mgd came from the Floridan aquifer. The International
Paper Company was the largest user of water, using about 13.5 mgd
from the Floridan aquifer and about 1.5 mgd from the water-table
aquifer. In February 1964 this company started receiving water from
Deer Point Lake at the rate of about 30 mgd. Ground-water use in
the Panama City area was reduced to about 11 mgd.
The first well in the Floridan aquifer was drilled in 1908. Later,
as the demand for water increased, more wells and well fields were
developed and water levels were lowered. By the end of 1963, when
water was being withdrawn at the rate of about 25.2 mgd, pumping
levels had been lowered as much as 200 feet near the centers of major
well fields. Pumping from the paper company well field, consisting
of 21 wells, was discontinued in February 1964 and water levels in
this field recovered 163 feet within 51 days.
The Deadening lakes in southeastern Washington County offer
considerable recreation potential. However, they lose water to the
ground at a high rate causing wide fluctuations in stage and this
prevents their full potential from being realized. The Washington
County Development Authority has proposed a plan to divert water
from Econfina Creek to stabilize these lakes at an elevation of 70
feet. The diversion from Econfina Creek would be at a point just
downstream from Tenmile Creek where the minimum flow was esti-
mated to be 30 mgd. The proposed plan calls for a detention reservoir
on Econfina Creek to raise the water level and make gravity flow
through a diversion canal possible. The storage in this reservoir,
added to the natural flow of the creek, would provide a minimum
flow of 40 mgd which would supply about 0.7 of a foot of water per
month on the 5,000-acre lake area.
Water leaks from the lakes to the Floridan aquifer at a rate pro-
portional to the head between the lake surfaces and the piezometric
surface of the aquifer. If the lake levels are maintained at a constant
elevation, the head that will be established depends on the ability of
the Floridan aquifer to transmit water away from the area.
If diversion from Econfina Creek is at a rate of 30 mgd, the stream






FLORIDA GEOLOGICAL SURVEY


just downstream from the point of diversion would be almost depleted
during periods of low flow. This effect will diminish downstream and
become almost negligible below Gainer Springs, a group of large
artesian springs just downstream from the Washington-Bay County
line. A diversion of 30 mgd is a negligible part of the total flow of
650 mgd into Deer Point Lake and would have no adverse effect on
this water supply. A part of the water diverted to the lakes would be
merely re-routed through the lakes into the ground and back to the
Econfina Creek through the artesian springs below the dam.
Deer Point Lake is a fresh-water lake formed November 17, 1961,
by a salt-water barrier across North Bay. It covers 4,700 acres and
stores about 32,000 acre-feet of water. The lake elevation is 5.0 feet
above mean sea level and fluctuates very little.
Artesian spring water flows from the Floridan aquifer into Econ-
fina Creek directly through the streambed, from the base of rock
bluffs and from short runs about a quarter of a mile in length. These
springs occur from a point just east of Porter Lake downstream to a
point near the Bennett gaging station. Springs contribute about two-
thirds of the flow of Econfina Creek.







REPORT OF INVESTIGATIONS No. 41 51

REFERENCES

Foster, J. B. (also see Toler, L. G.)
In Preparation Geology and ground-water hydrology of Bay County,
Florida.
Gunter, Herman (see Sellards, E. H.)
Hantush, M. S.
1955 (and Jacob, C. E.) Non-steady radial flow in an infinite leaky
aquifer: Am. Geophys. Union Trans., V-37, No. 6, p. 702-714.
Lang, S. M.
1961 Methods for determining the proper spacing of wells in artesian
aquifers: U.S. Geol. Survey Water-Supply Paper 1545-B.
Musgrove, R. H. (see Toler, L. G.)
Sellards, E. H.
1912 (and Gunter, Herman) The underground water supply of west-
central and west Florida: Florida Gzol. Survey 4th Ann. Rept.,
p. 116.
Shampine, W. J. (see Toler, L. G.)


Theis, C. B.
1935 The relation of the lowering of the
rate and duration of discharge of
storage: Am. Geophys. Union Trans.
1964 The spacing of pumped wells: U.S.
Paper 1545-C, p. 113.


Toler, L. G.
1964 .


piezometric surface and the
a well using ground-water
p. 519-524, August.
Geol. Survey Water-Supply


(and Musgrove, R. H., and Foster, J. B.) Freshening of Deer
Point Lake, Bay County, Florida: Am. Water Works Assoc.
Journal, V. 56, No. 8, p. 984-990.


1965 (and Shampine, W. J.) Quality of water from the Floridan aquifer
of the Econfina Creek basin area, Florida: Florida Geol. Survey
Map Series No. 10.




Water resources of the Econfina Creek Basin area in Northwestern Florida ( FGS: Report of investigations 41 )
CITATION SEARCH THUMBNAILS PDF VIEWER PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00001228/00001
 Material Information
Title: Water resources of the Econfina Creek Basin area in Northwestern Florida ( FGS: Report of investigations 41 )
Series Title: ( FGS: Report of investigations 41 )
Physical Description: 51 p. : illus. ;
Language: English
Creator: Musgrove, Rufus H
Foster, J. B ( James B )
Toler, L. G ( jt. author )
Publisher: s.n.
Place of Publication: Tallahassee
Publication Date: 1965
 Subjects
Subjects / Keywords: Groundwater -- Florida -- Econfina Creek Basin   ( lcsh )
Water-supply -- Florida -- Econfina Creek Basin   ( lcsh )
Genre: non-fiction   ( marcgt )
 Notes
Statement of Responsibility: by R. H. Musgrove, J. B. Foster and L. G. Toler. Prep. by the United States Geological Survey in cooperation with the Florida Geological Survey.
 Record Information
Source Institution: University of Florida
Rights Management:
The author dedicated the work to the public domain by waiving all of his or her rights to the work worldwide under copyright law and all related or neighboring legal rights he or she had in the work, to the extent allowable by law.
Resource Identifier: aleph - 000957323
oclc - 01725690
notis - AES0059
System ID: UF00001228:00001

Downloads

This item has the following downloads:

( PDF )


Full Text






FLRD GEOLOSk ( IC SUfRiW


COPYRIGHT NOTICE
[year of publication as printed] Florida Geological Survey [source text]


The Florida Geological Survey holds all rights to the source text of
this electronic resource on behalf of the State of Florida. The
Florida Geological Survey shall be considered the copyright holder
for the text of this publication.

Under the Statutes of the State of Florida (FS 257.05; 257.105, and
377.075), the Florida Geologic Survey (Tallahassee, FL), publisher of
the Florida Geologic Survey, as a division of state government,
makes its documents public (i.e., published) and extends to the
state's official agencies and libraries, including the University of
Florida's Smathers Libraries, rights of reproduction.

The Florida Geological Survey has made its publications available to
the University of Florida, on behalf of the State University System of
Florida, for the purpose of digitization and Internet distribution.

The Florida Geological Survey reserves all rights to its publications.
All uses, excluding those made under "fair use" provisions of U.S.
copyright legislation (U.S. Code, Title 17, Section 107), are
restricted. Contact the Florida Geological Survey for additional
information and permissions.






STATE OF FLORIDA
STATE BOARD OF CONSERVATION
DIVISION OF GEOLOGY




FLORIDA GEOLOGICAL SURVEY
Robert O. Vernon, Director




REPORT OF INVESTIGATIONS NO. 41




WATER RESOURCES
OF THE
ECONFINA CREEK BASIN AREA
IN
NORTHWESTERN FLORIDA
By
R. H. Musgrove, J. B. Foster, and L. G. Toler




Prepared by the
UNITED STATES GEOLOGICAL SURVEY
in cooperation with the
FLORIDA GEOLOGICAL SURVEY

TALLAHASSEE
1965










FLORIDA STATE BOARD

OF

CONSERVATION


HAYDON BURNS
Governor


TOM ADAMS
Secretary of State




BROWARD WILLIAMS
Treasurer




FLOYD T. CHRISTIAN
Superintendent of Public Instruction


EARL FAIRCLOTH
Attorney General




FRED O. DICKINSON, JR.
Comptroller




DOYLE CONNER
Commissioner of Agriculture


W. RANDOLPH HODGES
Director






LETTER OF TRANSMITTAL


'9orida jBeological QuTrvey

TALLAHASSEE

July 20, 1965

Honorable Haydon Burns, Chairman
Florida State Board of Conservation
Tallahassee, Florida

Dear Governor Burns:

The Florida Geological Survey will publish, as Report of Investi-
gations No. 41, a comprehensive report on the water resources of the
Econfina Creek Basin area in northwestern Florida. This report was
prepared by the members of the U. S. Geological Survey in coopera-
tion with the Florida Geological Survey, as a part of its water
resources study program.
The Econfina Creek is one of the largest discharging streams of
the State, and its potential for meeting water resources needs is great.
The publication of the total resources study, to be accomplished in
a series of papers, will contribute toward the stabilization of the
economic development of the Panhandle area, and will provide a
basis upon which a large water-using economy can be based.

Respectfully yours,
Robert O. Vernon,
Director and State Geologist



























Completed manuscript received
April 30, 1965
Published for the Florida Geological Survey
By The St. Petersburg Printing Co., Inc.
St. Petersburg, Florida
1965





PREFACE


In the planning and preparation of this report we have tried to
present the essential information that would provide a brief, concise
description of the water resources of the Econfina Creek basin area.
The report was designed to supply answers to general questions of
the many people interested in the water resources of the basin. Other
reports on particular aspects of the water resources of the basin will
present more detailed information about a phase of the hydrology or
geology of the basin. This report is intended to furnish the back-
ground from which the reader may refer to the phase reports for more
definitive treatments of a particular subject.
Special phases of the water resources of the basin will be featured
in reports on: Deer Point Lake; The Deadening area of southeastern
Washington County; geology and aquifers of Bay County; and a
quantitative study of ground water in the Panama City area. In addi-
tion, the basic data available through the period of investigation
will be published in the information circular series of the Florida
SGeological Survey.
This report was prepared by the Water Resources Division of the
U. S. Geological Survey in cooperation with the Florida Geological
Survey. The investigation was under the general supervision of Robert
0. Vernon, Director, Division of Geology, State Board of Conserva-
tion; A. 0. Patterson, district engineer, Surface Water Branch; C. S.
Conover, district engineer, Ground Water Branch; and K. A. Mac
Kichan, district engineer, Quality of Water Branch, of the U. S.
Geological Survey.
A number of individuals and organizations have been most gener-
ous in supplying information, equipment, and time in the process of
collecting data for this report. The courtesies extended by the follow-
ing persons are most appreciated: W. C. Cooper of W. C. Cooper
Plumbing and Heating Co.; H. L. Berkstresser and W. H. Galloway
of the Water and Sewage Department of Panama City; G. Layman,
construction engineer for Gulf Power Co.; W. H. Toske and M. G.
Southall of the U. S. Navy Mine Defense Laboratory; R. B. Nixon
and J. L. Gore of the Tyndall Air Force Base water department; J. M.
Lowery and T. M. Jones of the International Paper Co.; A. G. Symons
and R. H. Brown of the Layne-Central Co.; W. Brown of the Brown
Well and Pump Co.; and J. W. Spiva of Modern Water Inc.
Data on the chloride content in water from Deer Point Lake
during the period of freshening were furnished by the Florida State
Board of Health.







PREFACE


We would like to express special appreciation to Judge Ira A.
Hutchison who through his interest in water resources and in par-
ticular the geology of this area has been most helpful. Claude Hicks
has volunteered invaluable assistance in the collection of water-level
information in the Deadening lakes area.
We would like to thank the numerous citizens in the basin who
gave us access to their wells and who furnished us with information
on their water supplies.







CONTENTS

Page

Preface .............. ---... ---...---- --......--.. .-----..-..-.---- v

Abstract ...-----.............--......---......-............ -.. --.-........................ 1

Introduction ---...........---..-.........- ....... .... ---. ---.. .........---- 2

The hydrologic environment ---..-.....--.....-..-..--..---.------------- 4

General statement ...........-....-----...---. ...-- ..------------- 4

Physical make-up of the basin ...........-............------ ---..-- ..----... 4

Water movement .-.....---....--------------------------- 7

Water availability ;-......--...................--------.--------------- 8

Rainfall ...................... ........ ..... ..---- --------- --------- ------- 8

Water quality characteristics .--..-...-....-........-------- .--------- 9

Contamination by saline water .-......-...............----.........------- 11

Streamflow ..-.......-...--------..........----------------------- 15

Storage ...........--.------.....----..- -------- ----------- ------ 18

Lakes ..--............ .. -------.---. --------- -------- 18

Aquifers ......-...........--..-- -------------- -------- 19

Aquifer characteristics ................---------------------------- 20

Hydraulics of aquifers ......-.......---- .......--- ---- ------------22

Aquifer tests ....-...................-- ..-------------------- 24

Water use ......................---------- ---------------------------- 27

Water high lights of the basin .--..-...-..-...... ---------------------. 29

Decline of water levels in the Panama City area ...---...---...--...--..-.......----.. 29

General statement .........-- ........---------------------- 29

History of ground-water development ..--------................. .............31

vii







Page

The Deadening lakes ....-...-..........--.--...---------.......------ --------35

Geologic and hydrologic setting ..--......--..-...........--------------- 37

Water levels ...--............---.......--------------------- 37

Flow of Econfina Creek .......-.................------- -------------40

Springs ..........-- ..---.......--- -----... ---------- ---------- 41

Deer Point Lake .........--.....---- ---------------------- 45

Summary -..----- ---- -------------------------.----- 45

References .......-..---........----------------------------- 51







































viii








ILLUSTRATIONS

Figure Page
1 Map of Econfina Creek basin area ........--......................---............. 3

2 Map of Econfina Creek basin showing physiographic divisions and
surface runoff --................. ....-- .-..-- ..--.......--.......-....--.................. Facing p. 4

3 Geohydrologic sections of Econfina Creek basin area --...-..-.......----...--...-- 6

4 Bar graphs of maximum, minimum, and average monthly rainfall, and
annual rainfall, at Panama City from 1935 to 1963 ....-...-- .....-- ..---------...... 9

5 Map of Econfina Creek basin area showing location of data-collection
points referenced in report -....--.......-...-..----.....--.....---------------...............-.... 12

6 Scatter diagram showing relation of chloride to total mineral content
of water from the Floridan aquifer in the Econfina Creek basin area .... 13

7 Block diagram of Econfina Creek basin showing areal distribution of
mineral content and chloride concentration in water from selected wells
in the Floridan aquifer -....--...--.............- .......- ................... -......... ......-- 14

8 Graphs of chloride concentration in water from selected wells in the
Floridan aquifer .............------..--.......-....-........--......-- .. ....------------.---- 15

9 Flow chart of streams in the Econfina Creek basin -..-....--...---........-....-- ... -- 17

10 Graphs of water level in the water-table aquifer and rainfall near
Bennett for part of 1962 and 1963 ..----.......----......................--.......-- .-- 19

11 Graph of streamflow of Econfina Creek near Compass Lake for the
period April 1 to May 7, 1963 ......-..-...-........--------..-- ..-- .------. -----. 20

12 Sketch showing similarity of an artesian pressure system and water
pressure developed by an elevated tank .--..........---.................------ ..------ 21

13 Map showing the piezometric surface of the Floridan aquifer in the
Econfina Creek basin area, October 1962 ...----.........-..---...--...-...--- --.-- 23

14 Graphs showing theoretical drawdowns in the vicinity of wells being
pumped at a constant rate for selected periods .....-...-.....-...........-...-- ...... 26

15 Theoretical drawdowns along a line of 10 wells after 100 days of
pumping at a rate of 200 gallons per minute at each well -..--.....-..--.... 27

16 Graphs of water use and population in the Panama City area -...-....-.... 30

17 Map of the Panama City area showing the location of water wells for
each water system and the area supplied by these systems -..--..-..........--.. 31

18 Map showing the approximate piezometric surface of the Floridan
aquifer in the Panama City area in 1908 ---.........---..-.--... -~.. ------. 32

ix








Figure Page

19 Graph of water levels in observation well 008-537-332 near the center
of the International Paper Company well field for the period 1951
to 1963 .-..-..-.........................- .................-........-..............................----........... 33

20 Map showing the piezometric surface of the Floridan aquifer in the
Panama City area in April 1947 ....-......--.......-...................--...-..................... -35

21 Map of White Oak Creek basin in southeastern Washington County
showing The Deadening area ..-..-.........-................. .... ...-------........................ 36

22 Geohydrologic sections through the White Oak Creek basin, south-
eastern W ashington County .............................-.............. .......-- ......----- -....... 38

23 Graphs of water levels and rainfall in the vicinity of the Deadening
lakes .....----------------------.. ....... .... .............. ....................... ................. ........ 39

24 Flow chart of Econfina Creek during the low-water period of May 1963
showing the effect on streamflow if 30 mgd were diverted at the proposed
dam site .---------.--....... -............-----------------------..................................... 42

25 Flow chart of Econfina Creek showing spring flow ......-............................... 43

26 Graphs of streamflow, spring flow, and specific conductance for Econfina
Creek near Bennett for 1963 ..----.......................... ................- ...................... 44

27 Graph showing the relation of chloride in water in Deer Point Lake to
fresh water inflow --...-----.. .... ...........-----------------.......................... 46

28 Graphs showing the rise of water levels and change in chloride content
of ground water after construction of Deer Point Dam ...............--.....-..-- .. 47



TABLES

Table Page
1 Drainage areas, average flows, and low flows of subbasins within the
Econfina Creek basin ------ -----............-------------------.................................. 16

2 Record of water supply systems in the Econfina Creek Basin area .......... 28








WATER RESOURCES
OF THE
ECONFINA CREEK BASIN AREA
IN
NORTHWESTERN FLORIDA

By
R. H. Musgrove, J. B. Foster, and L. G. Toler

ABSTRACT
The Econfina Creek basin area of about 1,000 square miles is
located in northwestern Florida. Water use in the basin in 1963
averaged about 25.2 mgd (million gallons per day). The major uses
of water were for the manufacture of paper products, public and
domestic supplies, and recreation. Of the 25.2 mgd, 22.7 were pumped
from the artesian Floridan aquifer, mostly in the Panama City area.
In February 1964 use of lake water was started at the rate of about
30 mgd and ground-water withdrawal was reduced to about 11 mgd.
Since February 1964 the total use of water in the area has been about
41 mgd.
The basin receives most of its water from rainfall which averages
58.0 inches per year. Highly porous, unconsolidated sands form the
water-table aquifer and absorb much of the rainfall. Seepage from
this aquifer is to the streams and to the underlying artesian aquifers.
The productive artesian Floridan aquifer underlies the entire basin
and is the aquifer from which the most water is pumped. A secondary
artesian aquifer is present in the southern part of the basin and is
intermediate in depth to the water-table and Floridan aquifers. Move-
ment of water through these aquifers is generally southwestward.
By 1963, water levels in the Floridan aquifer near Panama City
had been lowered 200 feet by pumping since the first deep well was
drilled in 1908. The large drawdowns resulted from heavy pumping of
closely spaced wells in this aquifer which has a low transmissibility
(1,300 to 31,000 gallons per day per foot). In January 1964, pump-
age from a field of 21 wells was stopped and water levels in this field
recovered 163 feet within 51 days.
Water from the water-table aquifer generally had a mineral con-
tent from 10 to 50 ppm (parts per million) and that from the sec-







FLORIDA GEOLOGICAL SURVEY


ondary artesian aquifer from 80 to 150 ppm. Water from the Floridan
aquifer increased in mineral content from 70 ppm in the northern
part to about 700 ppm in the southern part of the basin. Mineral
content of water from streams and lakes, exclusive of those receiving
artesian spring flow, was from 6 to 25 ppm. Water from springs had
a mineral content from 50 to 68 ppm and was similar to water from
the Floridan aquifer in the upper part of the basin.
Streamflow into the coastal bays is at an average of about 960
mgd. Flow to North Bay is about 680 mgd, of which about 650 mgd
flows through Deer Point Lake. East Bay receives about 210 mgd,
and West Bay about 70 mgd. Runoff from the lower half of the drain-
age of Econfina Creek is 90 inches per year. This is about three times
the runoff from the upper half of the basin and is a result of artesian
spring flow.
There are about 80 named lakes in the basin, some of which have
a wide range in stage. A plan has been proposed to divert water from
Econfina Creek to a group of these lakes in southeastern Washington
County to stabilize their levels. At the proposed point of diversion,
Econfina Creek has a minimum flow of 30 mgd, which would supply
about 0.5 of a foot of water per month on the proposed lake area.

INTRODUCTION
This report describes and evaluates the water resources of the
Econfina Creek basin area located in northwestern Florida. The area
encompasses about 1,000 square miles and includes most of Bay
County and parts of Calhoun, Gulf, Jackson, and Washington coun-
ties, as shown in figure 1. As considered in this report, the Econfina
Creek basin area includes all basins that drain into the bay system
within Bay County.
Over 90 percent of the 70,000 people in the basin are located near
the coast and are centered in the Panama City area. In 1963, water
use in the basin was at the rate of 25.2 mgd. The three largest water
users were the International Paper Company, Panama City, and
Tyndall Air Force Base.
Ground-water levels were known to be below sea level in well
fields supplying the major users. Information was needed to determine
the extent of the low water levels and their effect on the water re-
sources of the area.
More than 80 fresh-water lakes are situated in the higher parts
of the area, mostly in southeastern Washington County. Included
is a group of lakes locally known as The Deadening. Considerable







REPORT OF INVESTIGATIONS No. 41


Figure 1. Map of Econfina Creek basin area.


interest has been expressed concerning the development of The Dead-
ening lakes into a water-oriented recreational area. Widely fluctu-
ating lake levels rendered this recreation plan infeasible without
lake controls. The Washington County Development Authority has
a plan to stabilize these lakes by water diverted from Econfina Creek.
Data were collected during the investigation to evaluate this plan.
No formal reports on the water resources of the area were avail-
able before this investigation. Some data were available on ground-
water levels, streamflow, and the chemistry of ground water. This
report is based on a 2-year investigation which began in January
1962. The investigation was designed to provide a basis for an evalu-
ation of the water resources of the Econfina Creek basin.






FLORIDA GEOLOGICAL SURVEY


THE HYDROLOGIC ENVIRONMENT

GENERAL STATEMENT

Water in the natural state continually moves due to many forces
acting upon it. Gravity acts on water in streams and underground
to keep it moving downward toward the level of the ocean. The sun
and wind evaporate water from open water bodies and plants trans-
pire water to the atmosphere. Gravity again moves the water earth-
ward when the atmospheric moisture meets conditions favorable for
rain. This never ending movement of water is known as the hydro-
logic cycle.
The water resources of any area depend upon this hydrologic
cycle. When the rate of water movement out of an area exceeds the
rate of water movement into the area, water shortages will develop.
Water shortages may also develop if the quality of water is signifi-
cantly altered within its natural environment to make it unfit for its
intended use. Variations in the rate of movement in any phase of the
hydrologic cycle, such as rainfall, may also affect an area by result-
ing in floods and droughts. Proper development of the water resources
of an area requires a thorough knowledge of water movement and
the factors controlling it. This knowledge will enable the best pre-
diction of where to obtain water and what provisions are required
to control water movement.
In general, the system through which water moves in the Econ-
fina Creek basin is similar to most river basins in Florida. Like most
other basins, (1) rainfall is the source of all the water even though
some falls outside the basin and moves into the basin underground;
(2) the surface materials are highly porous, unconsolidated sands;
(3) the basin is underlain by the artesian Floridan aquifer; and
(4) water leaves the basin by streamflow, evaporation, transpira-
tion, underground flow to the ocean and other basins, and by con-
sumptive use.

PHYSICAL MAKEUP OF THE BASIN

Four physiographic divisions within the basin affect the surface
drainage and the water storage. These are the sand hills, sinks and
lakes, the flat-woods forest, and the coastal beach sand dunes and
wave-cut bluffs, shown in figure 2. The physiographic divisions have
developed on a series of stair-step marine terraces which were carved
into the surface sands during the ice age by the successive levels of









55' 50' 45' 40 35' 30' 25' 20' 15' 8310


ECONFINA CREEK BASIN AREA

3035 Sevenfenmi/le 30'33
Pond



30 GREENHE -30
TAIN








20 -20










IO T 4 CIT
EXPLANATION


PHYSIOGRAPHIC DIVISIONS 5

E Sand hills
Sinks and lakes a
S Flat- woods forest 3
--- Beach dunes and wave-cut bluffs

37 Numbers represent average annual
runoff in inches from areas out- WrEERWAy
lined by dashed linesI
86oo' 55' 50' 45' 40' 35' 3o' 25' 20' 15' 85l0'

Figure 2. Map of Econfina Creek basin showing physiographic divisions and
surface runoff.


8600d










REPORT OF INVESTIGATIONS No. 41


the ocean. Low swampy areas occur throughout each of these divi-
sions but are more prevalent in the flat-woods forest.
The sand hills in the northern part of the basin are erosional
remnants of the higher marine terraces which were between 100 feet
and 270 feet above the present sea level.
The sinks and lakes occur in the section of the basin west of
Econfina Creek where they have developed within the sand hills. This
area is typified by irregular sand hills and numerous sink holes and
sink-hole lakes. The sink holes range in diameter from a few feet to
broad flat areas such as those in The Deadening lakes area (see p. 73).
This physiographic division was developed by the solution of the
underlying limestone and the subsequent collapse of the overlying
material into the solution chambers. Most of the lakes have no sur-
face outlets.
The flat-woods forest is the largest physiographic division of the
basin. It is slightly rolling to flat land lying on the terraces below an
elevation of 70 feet. Most of this division is covered with pines except
for a few small areas cleared for agriculture. The flat-woods forest is
well drained except for some low areas around the bays on the 0 to
10 and 10 to 25 foot terraces. During rainy weather these low areas
of the flat woods become quite wet. A few small perennial swamps
occur at various locations throughout the flat-woods forest. The larg-
est is Bearthick Swamp southeast of Youngstown which covers an
area of about 2,000 acres (fig. 2).
The fourth physiographic division occurs adjacent to the gulf
coast and is characterized by beach dune deposits and wave-cut bluffs.
The beach dune deposits are the youngest sediments in the basin and
are the most rapidly changing physiographic feature.
The surface materials in the basin, on which the physiographic
features have developed, are generally very porous, permeable sands.
The sands form the water-table aquifer which is thicker in the sand
hills (80 to 100 feet) than in the lower elevations of the flat-woods
forest (10 to 30 feet) and thickens again along the coast (65 to 140
feet). The sands are missing only in stream channels and in some
parts of the broad depressions of the sinks and lakes division.
The sands of the water-table aquifer cover a relatively imperme-
able layer of sandy clay and clayey shell material which forms an
aquiclude (a formation that confines water to aquifers above and
below it) between the water-table aquifer and the artesian aquifers
below it, as shown in figure 3. This aquiclude is present throughout
the basin except where it has been breached by a collapse into solu-
tion chambers or by erosion along Econfina Creek.









120 0

N2O

240- T -240
160- 160








sJso
S e 0 0S
T T1` I L I 1,1 T.", '
so % ,. .. i..... 0.1 ..- 1-s
160 AU 1.1 4 -. 160
.LORIDAN A. WU I-------E4LANATION0

I n Shells n
400- MC IC17Y : 77-L -L L=IL 11 ;LI la 400 J
. j .-490
SLimestone








so en B 60 e
Se Im 0Sa 1001t


-160- -' AQ CEUBE A QUICLUDE --160-240
.,,.,, _,,, -----240-
.3m i .32


-4848
1E E ..II IJ FLORIDAN AQUIFER
MA0.60
.640640
0 I 2 3 4 5 10 miles

Figure 3. Geohydrologic sections of Econfina Creek basin area.





REPORT OF INVESTIGATIONS NO. 41


In the bay area and along the gulf coast in the basin, two artesian
aquifers are associated with the aquiclude. Here the aquiclude is
thicker than it is to the north and is overlain and in part underlain
by some shell-hash beds which contain water. The sandy clay material
which forms the base of the water-table aquifer is sufficiently imperm-
eable to confine water in the shell-hash beds under artesian pressure.
Water producing zones in the shell-hash beds above the aquiclude
are termed the secondary artesian aquifer. The water producing zones
in the shell-hash beds below the aquiclude are considered part of the
Floridan aquifer.
The Floridan aquifer underlies the entire basin below the aqui-
clude. It is composed of limestone formations that are as much as
1,200 feet thick. However, the usable part of the aquifer, the part
producing potable water, is the upper 500 to 700 feet.

WATER MOVEMENT
Rain, falling on the basin, is readily absorbed by the porous sur-
face sands. The portion that runs off directly to the streams depends
on the amount and intensity of the rainfall. The rain water and the
surface water are relatively pure but contain some salts carried in
the evaporate from the ocean and some gases dissolved from the at-
mosphere. The surface water becomes colored after contact with
decayed organic matter but the mineral content changes very little.
The water absorbed by the sands seeps downward to the water
table, the level below which the sand is saturated. The sands are not
very soluble in the rain water and consequently the mineral concen-
tration in water from the water-table aquifer is low.
Some of the water then moves from the water-table aquifer into
the streams and maintains flow during periods of no rainfall. In the
northern part of the basin where the sand and clay are breached by
sinkholes, some of the runoff and seepage from the sands is tempo-
rarily ponded in lakes and then moves into the Floridan aquifer. In
other areas the water from the sands may seep slowly into the lime-
stone through the clay layer.
The amount of water moving from the water-table aquifer to the
Floridan aquifer diminishes toward the southwest because the aqui-
clude is thicker. Water that moves downward into the limestone of
the Floridan aquifer then moves in the down gradient direction shown
by the piezometric map (see p. 23). The gases acquired from the at-
mosphere and from the soil zone form a weak acid solution which dis-
Lolves the limestone and thereby causes an increase in the mineral






FLORIDA GEOLOGICAL SURVEY


content of the water. The mineral content of the water increases in
the down gradient direction as more limestone is dissolved.
In areas along Econfina Creek where the artesian pressure surface
is above the land surface and the sand and clay are missing, springs
have developed. Most of the flow of Econfina Creek is derived from
these springs.
In the southern half of the basin, water may percolate downward
from the water-table aquifer into the secondary artesian aquifer. The
sandy clay material at the base of the water-table aquifer and at the
top of the secondary artesian aquifer acts as a semi-confining layer
which maintains the water in this aquifer under artesian conditions.
The secondary artesian aquifer is composed of shell-hash with
interlayered sand and limestone lenses. Water that moves into this
aquifer from the water-table aquifer is slightly acid. This water
dissolves the limestone and shell giving the water a calcium bicarb-
onate character.
The water withdrawn from wells in the Floridan aquifer in the
Panama City area entered the aquifer through the sinks in the north-
ern part of the basin and in areas farther north where the limestone
formations are at ground surface. By the time the water reaches
Panama City the mineral concentration is five to six times that of
water in the northern part of the basin. Part of the increase is caused
by solution of the limestone and part is caused by mixing with older
water in the rocks. The pressure gradient shows that the water is being
flushed into the ocean at some point where the rocks are exposed to
or hydraulically connected to the ocean bottom.

WATER AVAILABILITY
The amount of water moving through each part of the hydrologic
system must be known to properly evaluate a water resource. A
knowledge of the environment is necessary to determine the chemical
and physical properties of the water and to predict any changes in
these properties that may result from withdrawal of water from the
system. Some of the parameters that affect the amount and quality
of water available are rainfall, streamflow, water levels, rock com-
position, and the ability of aquifers to store and transmit water.
These hydrologic features can be measured either by direct or in-
direct methods.
RAINFALL
The Econfina Creek basin receives an average rainfall of 58 inches
per year, based on records collected at Panama City by the U. S.






REPORT OF INVESTIGATIONS No. 41


Weather Bureau. During the past 29 years the annual rainfall at
Panama City has varied from 37.6 inches to 85.0 inches. Graphs
showing variations in rainfall are given in figure 4. Short periods

25 100

W20 ---- 80
AVERAGE 57.98
Z MAXIMUM- z
z 15 60" u


J 0 40------ --




JFMAMJ JASON o o


Figure 4. Bar graphs of maximum, minimum, and average monthly rainfall,
and annual rainfall, at Panama City from 1935 to 1963.

of low rainfall and short periods of high rainfall have little direct
effect on the water resources; that is, the amount of water in storage.
Extended periods of below-average rainfall, or droughts, cause reduc-
tion in storage. The most severe drought of record ended in 1956
with a 7-year deficiency in rainfall of 50.2 inches. Within this 7-year
period, 1953 was a single year of above-average rainfall but did not
bring about a complete recovery of water lost from storage during
the preceding years of low rainfall. The 6-year period from 1944 to
1949 was the wettest of record. Records of water levels indicate that
storage was near an all-time high during this wet period.


WATER QUALITY CHARACTERISTICS
The water in the lakes and streams of the area has about the
same mineral concentration as rain water. Samples of rain water
contained as much as 13 ppm of dissolved mineral matter; the water
in the streams and lakes ranged from about 6 to 25 ppm. The mineral
concentration of the surface water differs little from rainwater because
of the relative insolubility of the surface materials. During periods
of low flow, high mineral concentrations are normally expected in
stream water because a large part of the flow is seepage from the






FLORIDA GEOLOGICAL SURVEY


water-table aquifer. No difference in the chemistry of surface water
in the basin was noted between high and low flow except for the color
and pH. High color immediately following a rain is attributed to the
flushing of the decayed organic material from the swampy, poorly
drained areas adjacent to the streams. This same colored water tends
to be acid due to the solution of carbon dioxide released from the
decaying plants. The pH of the streams is lower (more acid) during
high flow when the flushing of the swampy areas occurs. The pH
normally ranges from 6.0 to 7.0 units but falls below 6.0 during
these times.
Two areas of exception to the normal low mineral concentration
in stream water occur in the Econfina Creek basin. One of the areas
is along Econfina Creek downstream from a point about due east of
Porter Lake, where the creek receives flow from artesian springs.
These springs emanate from limestones of the Floridan aquifer and
the chemistry and relative solubility of the rocks are reflected in the
mineral constituents found in the water. The mineral concentration
in water from the springs ranged from 50 to 68 ppm and all but about
10 to 12 ppm were calcium and magnesium carbonate, the constituents
of limestone. The mineral content of the water in Econfina Creek,
downstream from where spring water enters, is higher than that in
other streams in the basin, and varies with the ratio of spring flow
to surface runoff. Calculations, based on chemical analyses, (see
p. 84), show that 70 to 75 percent of the base flow of Econfina Creek
at the Bennett gaging station is from springs.
The other area of exception to normal low mineral concentrations
in stream water is near the mouth of the streams which empty into
salt-water bays. Salt water moves up the streams a distance that is
dependent upon the elevation of the streambeds, the stage of the
streams, and tides. This encroachment of saline water occurs in the
mouths of all streams except those emptying into Deer Point Lake,
which is a fresh water body.
That part of the rainwater that replenishes the aquifers continues
to move in the hydrologic cycle but at a slower rate than the water
moving as surface flow. This slow rate of movement allows a state of
chemical equilibrium to be approached and normally results in ground
water having a higher concentration of mineral constituents than does
the surface water in an area. The highly insoluble nature of the sands
which form the water-table aquifer in the Econfina Creek basin
results in low mineral concentration of water in this aquifer. Gen-
erally, the concentration of total mineral constituents in water from
this aquifer ranged from 10 ppm (about equal to that of rainwater)






REPORT OF INVESTIGATIONS NO. 41


to about 50 ppm. In areas near the coast these sands are in contact
with salt water. All water from the water-table aquifer which con-
tained more than 50 ppm dissolved minerals was from wells located
within a few hundred feet of salt-water bodies.
Water in the secondary artesian aquifer is slightly more mineral-
ized than water in the water-table aquifer. In some areas near the
coast the water from this aquifer may be saline. Where there is no
contamination by saline water, the water generally contains from 80
to 150 ppm dissolved minerals and is principally a calcium bicarbonate
water. Most of the water samples contained hydrogen sulfide and some
samples contained sulfate.
The mineral concentration of water from the Floridan aquifer is
higher than that from the secondary artesian or the water-table
aquifers. In the northern part of the basin the higher mineral content
is due entirely to higher concentrations of calcium and bicarbonate
resulting from solution of the limestone. There are definite trends in
mineral concentrations in water in the Floridan aquifer. These trends
have been mapped (Toler and Shampine, 1964) and generally show
increases in all constituents toward the southwest. An adaptation of
the map of dissolved solids is shown on page 14 and indicates the
trend of all the constituents. Sulfate, sodium, and hydrogen sulfide
show little trend, but are found in significant quantities in the
southern half of the basin. In this area, sulfate ranged from 0 to
81 ppm, sodium from 2 to 164 ppm, and the odor of hydrogen sulfide
was detected in water from most wells.

CONTAMINATION BY SALINE WATER
The large bays in the southern half of the Econfina Creek basin
provide an access for salt water several miles inland. Along the shore-
line of these bays and along the Gulf, the salt water is in contact with
the sands which form the water-table aquifer. During droughts, when
the water levels in the sands are low, salt water may enter the aquifer
and be pumped from shallow wells near the shore. Salt water is more
dense than fresh water and it moves into the aquifer in the form of
a wedge below a lens of fresh water. Fresh water will generally sup-
press the salt water about 40 feet below sea level for every foot of
elevation of fresh water above sea level. If the water level in the aquifer
is lowered by pumping, the saline wedge adjusts to the new water
levels and salt water may rise to contaminate a well. An interzone of
water of intermediate composition is normally present instead of a
sharp fresh-water salt-water interface.






FLORIDA GEOLOGICAL SURVEY


Salt water may enter the secondary artesian aquifer from the bays
or from the water-table aquifer, when the pressure surface of the
secondary artesian aquifer is below the water level of either source.
Highly saline water from the secondary artesian aquifer was observed
in samples from two wells. One well (007-535-334a), shown in figure 5


Figure 5. Map of Econfina basin area showing location of data-collection points
referenced in report.

is 76 feet deep and the water contained 1280 ppm chloride. The other
well (008-545-224, fig. 5) is 101 feet deep and the water contained






REPORT OF INVESTIGATIONS NO. 41


1090 ppm chloride. Both of these are adjacent to saline surface-water
bodies. Wells penetrating the underlying Floridan aquifer, at and
near these locations, produce water low in chloride. The saline water
is presumed, therefore, to have leaked from the bays through the
water-table aquifer.
Apparently, the aquiclude overlying the Floridan aquifer (fig. 3)
in the coastal and bay area is sufficiently impermeable to prevent
leakage of water from the overlying aquifers. The occurrence of
chloride in water in the Floridan aquifer does not appear to be
related to areas of high chloride in water in the overlying sediments
or to the bays. Water levels in the Floridan aquifer have been lowered
below water levels in both the water-table aquifer and the secondary
artesian aquifer, by pumping in the major well fields. Extended periods
of low water levels in the Floridan aquifer have not resulted in an
increase in the chloride concentration of water from this aquifer as
would be expected if the aquiclude were leaking.
The chloride content of the water increases southwestward, the
general direction of water movement. The fresh water apparently
mixes with saline water in the aquifer to account for the increase in
chloride. Figure 6 shows the relation of the increase in total mineral


z
0
-J
W
L.


Cd,
0
z


S


%UU


300
Only those samples containing greater
than 5 ppm chloride included "



100



0, ------ ---'-L:---- -------_ -----_---- -----_________ ________
o --~ /"
.. . .. .. .. .. .


S 01U 200 300 400 500 600 700 800 900
MINERAL CONTENT, IN PARTS PER MILLION
Figure 6. Scatter diagram showing relation of chloride to total mineral content
of water from the Floridan aquifer in the Econfina Creek basin area.


concentration of the water to the increase in chloride for all samples
containing more than 5 ppm chloride.
Figure 7 is a block diagram of a section along the coast showing
chloride concentrations and water producing intervals of wells pene-







FLORIDA GEOLOGICAL SURVEY


Chloride, in ppm


.- -'-- Top of the Floridon Aquifer


,. 250- Dissolved solids in parts per million
(adaptd trom Tole and Shampine, 1964)
275
Well (number indicates dissolved solids in ppm)
Figure 7. Block diagram of Econfina Creek basin showing areal distribution of
mineral content and chloride concentration in water from selected wells in the
Floridan aquifer.







REPORT OF INVESTIGATIONS No. 41


treating the Floridan aquifer. The chloride concentration generally
increases with depth into the aquifer. No chloride mineral is present
in the rock-forming materials and if water is not leaking from the
overlying rocks, then this saline water must be residual water that
remains in the rocks from a time when they were in contact with the
sea. The geologic history (Foster, in preparation) indicates this may
have happened many times. The residual water in the rocks would be
from sea water and chemically would probably differ little from
present sea water.
Records of chloride content in water from four wells, from 1950 to
1963, are given in figure 8. Although there is considerable variation


400 ---400

350 30
004-53- \ 333




loo...a. -auI /\ i
S 010-545-412_ -"K
604 ft. eei p



S *.." .-.*..- A II 1\ A /\ /\ ..-/'.. oo l.s6-,21 ".
l st e a te rt o lw. l t i imptt i
00- f V




t 19530 191 135Z 195 1954 123 19535 12537 3 19 5 560 156 1 619Z 1931 0
Figure 8. Graphs of chloride concentration in water from selected wells in the
Floridan aquifer.

in the chloride concentration, thr there ro be no long-term trends
due to pumping.


STREAMFLOW
In using a stream, two quantitative aspects to be considered are
channel storage and the rate of flow. Channel storage is important in
considering uses such as boating, fishing, and other recreational activi-
ties. The rate of flow must be considered when determining the quan-
tities of water that can be withdrawn from the stream at any time.
Only the larger streams in the Econfina Creek basin have enough







FLORIDA GEOLOGICAL SURVEY


channel storage during periods of low water to be used for boating.
Most of the streams have sufficient flow to be a potential water sup-
ply. During periods of minimum flows there is more than 10 times as
much fresh water flowing into the bays than is being withdrawn from
all sources in the Panama City area.
Streamflow in the basin comes from several sources. During and
immediately following rains water flows directly into the streams as
overland flow. Between rains the streams receive only water that seeps
from the shallow sands and from artesian spring flow from the lime-
stone formations. Every stream receives seepage from the shallow
sands.
Streamflow to the bays is at an average rate of about 960 mgd
which amounts to 40 percent of the average rainfall. About 650 mgd
flows through Deer Point Lake into North Bay from Econfina Creek,
Bear Creek, Big Cedar Creek, and Bayou George Creek. Another 30
mgd flows into North Bay below Deer Point Dam from smaller
streams. West Bay receives a flow of about 70 mgd from Burnt Mill
Creek, Big Crooked Creek and smaller tributaries. East Bay gets
about 210 mgd from Wetappo Creek, Sandy Creek, Calloway Creek,
and smaller streams.
Figure 2 shows values of runoff from areas within the Econfina
Creek basin. It can be seen from this map that the physiographic fea-
tures affect runoff. The low runoff in the southern half of the basin
results from the poor drainage of the flat-woods forest. Drainage in the
sinks and lakes division is mostly internal and there is almost no
surface runoff. High base flow due to seepage from the porous sands
causes the high runoff in the sand hills division. The extremely high
runoff of 90 inches from the lower half of Econfina Creek is a result
of the artesian spring flow.


TABLE 1. Drainage areas, average flows, and low flows
of subbasins within the Econfina Creek basin.

Drainage area Average flow Low flow
Creek basin sq. mi. mgd mgd
Econfina Creek --..-..--..........................-.... 129 355 226
Bear Creek .---.............. ............. ...........-... .... 128 226 52.
Wetappo Creek ---...-.....-..................... ... --77 80 6
Sandy Creek ----------........................ ... 60 70 10
Bayou George Creek ..-....-----...--..-... 51 26 3
Burnt Mill Creek --......................_.._... 45 23 8
Big Crooked Creek .-...--.. ..-..--....-....-----.. 22 17 6
Big Cedar Creek -............ --....-. ....- -- 62 12 4
Calloway Creek ...................._. __._.._.. .. 13 9 .6
All others ...................-....... ..... ..... 142 -







REPORT OF INVESTIGATIONS NO. 41 17

Stream data are given in table 1. The values of streamflow, except
those for Econfina Creek, are estimated from short-term continuous
discharge records or from periodic discharge measurements. The low
flow of a stream without storage reservoirs limits its use. Much more
water can be taken from streams if storage reservoirs are available
from which to draw during periods of extreme low flows.
The flow chart in figure 9 shows the streamflow pattern of the
basin. The average flow of Econfina Creek is 355 mgd, by far the
largest of all the streams. This is a runoff of 58 inches per year and is


FLOW CHART


flow in million gollons- per doy.
o soo mad
I I I I I
Floe Scale






FLORIDA GEOLOGICAL SURVEY


about equal to the annual rainfall on the drainage area of 129 square
miles. Streamflow records have been collected since 1936 at Porter
Bridge near Bennett at a point where the drainage area is 122 square
miles.
The average flow of Econfina Creek from the upper half of the
basin is 90 mgd, only one-fourth of the flow from the entire basin.
Upstream from Tenmile Creek (fig. 1) the flow during dry periods is
seepage from the shallow sands. Downstream from Tenmile Creek
artesian springs contribute most of the dry-weather flow. The mini-
mum flow from the entire drainage area of Econfina Creek is about
210 mgd, or seven times the minimum flow of about 30 mgd from the
upper half of the drainage area.
Floods occur on Econfina Creek almost every year. The creek has
overflowed its banks at least once each year in all but six of the last
28 years. The longest period that it has stayed within its banks is the
3-year period August 1950 to September 1953.
Bear Creek is the second largest creek in the basin and has an
average flow of 226 mgd. It drains almost entirely from the sand hills
and flow is supported by seepage from these sands.
The average total surface flow into the bays was estimated as
960 mgd. Econfina Creek and Bear Creek contribute 581 mgd of this
flow. The remainder of the average flow (379 mgd) comes from the
smaller streams in the basin. The larger streams are listed in table 1.


STORAGE
Rainfall, although it varies, supplies an adequate amount of water
to the basin. Water held in storage in lakes and aquifers eliminates
frequent shortages which would result from the inconsistent rainfall.

LAKES
There are about 80 named lakes in the basin. Most of the lakes
are in southeastern Washington County. Deer Point Lake (see p. 87),
a fresh-water reservoir covering 4,700 acres in Bay County, is the
largest. Porter Lake in Washington County has a surface area of 930
acres and is the largest natural lake.
The natural lakes have not been developed for water use to any
great extent although they offer considerable potential as recreational
facilities. Wide fluctuations in most lake levels, caused by seepage
losses to the ground and variations in rainfall, discourage their devel-
opment. The Washington County Development Authority has pro-






REPORT OF INVESTIGATIONS No. 41


posed a plan to divert water from Econfina Creek to a group of lakes
known as The Deadening (see p. 73) and thereby stabilize their levels.
This plan, if executed, would add about 4,000 acres to the normal size
of this group of lakes.

AQUIFERS
The three aquifers the water-table aquifer, the secondary arte-
sian aquifer, and the Floridan aquifer store large quantities of
water. The portion of rainfall that enters these aquifers through down-
ward percolation is stored temporarily.
Water contained in the water-table aquifer discharges slowly by
downward percolation to the underlying aquifers and to the streams
and lakes through seepage and small springs. The water-table aqui-
fer, in the basin, is composed of fine to coarse sand and contains a
volume of water approximately one-fourth the volume of the saturated
section. The fluctuation of water levels in the water-table aquifer is
an indication of the change in storage, shown in figure 10. During dry
periods the water levels decline as the aquifer discharges the water
from storage. In wet periods water levels rise as more water is received
by the aquifer than is discharged.
Exclusive of flow from the artesian aquifer, the low flows of the
streams are maintained by seepage from the water-table aquifer and

0w-


-<')
_z- M__ODJMMSN


M w olO Well 023-532=124,
w 12- at Bennett

u) 14 -Rainfall station 2 miles west of Bennett



MIa JA lS 0o N D J IFMIA IM a J jA| S O IN D
1962 1963
Figure 10. Graphs of water level in the water-table aquifer and rainfall near
Bennett for part of 1962 and 1963.







FLORIDA GEOLOGICAL SURVEY


are indications of the size and ability of the water-table aquifer to
store and transmit water. Figure 11 is a graph of streamflow of Econ-
fina Creek near Compass Lake for the period April 1 to May 7, 1963.


0


z
a






S10 I5 20 25
APRIL 1963
Figure 11. Graph of streamflow of Econfina Creek near
period April 1 to May 7, 1963.
period April 1 to May' 7, 1963.


MAY
Compass Lake for the


The low-flow portion of this graph represents seepage from the water-
table aquifer. The nearly flat slope of the low-flow portion of this
graph, such as that immediately preceding the rise of April 30, shows
that storage of water in the aquifer is sufficient to maintain the low
flow for long periods of no rainfall.
The secondary artesian aquifer which is present along the Gulf
coast also provides for storage of water in the basin. This aquifer is
saturated at all times, therefore the volume of water stored in it does
not change. Water discharges from this aquifer to the Gulf and to
wells. There is some exchange of water between this secondary arte-
sian aquifer and the aquifers above and below.
The Floridan aquifer is the most extensive aquifer in the basin and
the one from which most water is obtained. A more detailed study
was made of the characteristics of this aquifer.

AQUIFER CHARACTERISTICS
Certain hydraulic features of aquifers are of prime importance to
water-supply planners and developers. These hydraulic features, ob-







REPORT OF INVESTIGATIONS No. 41


trained from well data, should be determined before the first well field
is developed. A thorough knowledge of the hydraulics of an aquifer will
enable the planners to predict how much water the aquifer will supply.
In the design of a well field the planner should know how much water
he can expect to pump from each well without overdrawing the aqui-
fer; what the optimum spacing of wells should be to keep pumping
interference between wells to a minimum; what the design of each
well should be as to the diameter, depth of casing, length and setting
for screens or depths of open hole in a consolidated rock aquifer; and
the required pump specifications.
The water in an artesian aquifer is under pressure much the same
as water in a pipe leading from an elevated water tank, as shown in
figure 12. The piezometric (pressure) surface in an artesian aquifer



Elevated
Tank Level to which water would rise in standpipes with no discharge
100 ------------------------
Level to which water would rise in
-_ a standpipe when water is
75 j discharging
> 75 *



z .50




200
0 --
UJ -/L' Cone of
150 Myy Depression
150
o Pumped
S\ Well

100 Ita
w Piezometric Surface

50- \
1 N!AQUUIFER
II i

Figure '12. Sketch showing similarity of an artesian pressure system and water
pressure developed by an elevated tank.







FLORIDA GEOLOGICAL SURVEY


is the level to which water will rise in cased wells drilled into the
aquifer, and is likened to the level of water in a vertical pipe that taps
a city water main. Water can be taken from an artesian aquifer and
the piezometric surface lowered without dewatering the aquifer. Only
when the piezometric surface is lowered below the top of the aquifer
is the aquifer dewatered. The quantity of water that can be withdrawn
without dewatering the aquifer depends upon the ability of the aquifer
to transmit water and the rate of recharge to the aquifer.

HYDRAULICS OF AQUIFERS
When a well that taps the Floridan aquifer begins to discharge
water, the piezometric surface surrounding the well is lowered. A cone,
centered at the discharging well, describes the shape of the lowered
pressure surface in the vicinity of the well. This lowered pressure sur-
face near a well or a group of wells in a producing field is referred to
as the cone of depression or cone of influence. This cone of depression
is graphically portrayed by the cones developed in the piezometric
surface of the Floridan aquifer in the vicinity of the well fields in the
Panama City area, as shown in figure 13.
In the initial stages of development the cone of depression is small
in diameter and depth. As discharge from the well continues the cone
spreads out. The lowering or drawdown of the pressure surface at the
well continues until the amount of water being discharged is balanced
by an equal amount being transmitted through the aquifer to the well.
This balance can be achieved by a decrease in natural discharge or an
increase in natural recharge.
When pumping stops the pressure surface begins to recover, rap-
idly at first, then at a progressively slower rate. With no further pump-
ing in the vicinity the pressure surface will eventually recover to the
initial level.
The response of an aquifer to pumping from one well or a group of
neighboring wells in terms of the rate and extent of drawdown in the
pressure surface, and the quantity of water that the aquifer will pro-
duce is related to the hydraulics of the aquifer at that location. The
principal hydraulic properties of an aquifer are its ability to transmit
and to store water.
An artesian aquifer, such as the Floridan aquifer in the Econfina
Creek basin, functions as a conduit through which water moves from
the areas of recharge to the areas of discharge. The aquifer's ability
to transmit water is expressed in terms of its coefficient of transmissi-
bility. It is the quantity of water, in gallons per day, that will flow






REPORT OF INVESTIGATIONS No. 41


Figure 13. Map showing the piezometric surface of the Floridan aquifer in the
Econfina Creek basin area, October 1962.

through a vertical section of the aquifer one foot wide and extending
the full height of the aquifer, under a unit hydraulic gradient, at the
Prevailing temperature of the water.
The coefficient of storage of an aquifer is the volume of water re-
leased from or taken into storage per unit surface area of the aquifer






FLORIDA GEOLOGICAL SURVEY


per unit change in head normal to that surface. This storage coefficient
for an artesian aquifer is a measure of the small amount of water re-
leased or taken into storage when the aquifer compresses or expands
due to changes in water pressure.

AQUIFER TESTS
The coefficients of transmissibility and storage are determined by
the analysis of data obtained by aquifer tests or pumping tests. Three
aquifer tests were carried out during the field investigation of the
Econfina Creek basin utilizing available wells in the Floridan aquifer.
In each of the three tests conducted, a well was pumped at a constant
rate while water levels were measured in the pumped well and in one
observation well.
A test of short duration was run at Bid-a-wee (fig. 5) using a
standby supply well and an observation well belonging to the city of
West Panama City Beach. The pump was operated for a period of 6
hours at a rate of 55 gpm (gallons per minute). The rate of drawdown
and the rate of recovery of the water level were measured in the obser-
vation well, 49 feet from the pumped well.
A similar test was made at Long Beach (fig. 5) in which one well
was pumped for a period of 5 hours at a rate of 328 gpm. In this test
the observation well was 1,800 feet from the pumped well.
The third test was made at the Lansing Smith Steam Plant (fig. 5)
northwest of Lynn Haven. In this test one well was pumped at a rate
of 504 gpm for a period of 50 hours. The observation well was 1,195
feet away.
The Theis graphical method (Theis, 1935) was used to compute
values of T (coefficient of transmissibility) and S (coefficient of stor-
age) from the test data. The following values of T and S were
computed:
Bid-a-wee test T=2,000 gpd/ft
S=1.2X 10-4
Long Beach test T= 4,000 gpd/ft
S=5 X10-4
Lansing Smith Steam Plant test T= 30,000 gpd/ft
S=3X 10-4
These computations are based on the assumptions that the aquifer
is (1) of uniform thickness; (2) of infinite areal extent; and (3) homo-
geneous and isotropic (transmits water equally in all directions). De-
terminations of T and S from data collected during these three tests
give a wide range of values and show considerable change in the hy-






REPORT OF INVESTIGATIONS NO. 41


draulic character of that part of the aquifer penetrated by the wells
at each of the test site locations. The wells used in the tests pene-
trated the upper 330 feet of the aquifer at Bid-a-wee, 245 feet at Long
Beach and about 250 feet at the Lansing Smith Steam Plant. None of
the wells used in these tests penetrated the full thickness of the aqui-
fer. Deeper wells would draw water from a greater thickness of the
aquifer and would, consequently, give higher values.
The values of the coefficient of storage from these tests are con-
sistent with values for the Floridan aquifer in other areas. The co-
efficient of transmissibility of the aquifer at the Lansing Smith Steam
Plant is higher than at the other test sites. This may indicate vertical
leakage into the aquifer from the overlying formations. Because the
tests show considerable differences in the coefficient of transmissi-
bility of the aquifer within the bay area, the coefficient of transmissi-
bility determined from pumping tests nearest a proposed well field
should be used. Additional tests should be made at distant locations
before a well field is designed.
In order to predict the amount and areal extent of drawdowns that
will result from different rates of pumping and different well spacings,
computations were made using the Theis formula (Theis, 1935) and
the coefficients of transmissibility and storage determined at the
Lansing Smith Steam Plant, at Bid-a-wee, and at Long Beach. Figure
14 shows theoretical drawdowns in the vicinity of a well discharging
at a constant rate for different lengths of time at the Lansing Smith
Steam Plant, the Long Beach, and the Bid-a-wee locations. These
drawdowns represent the conditions that would result from continuous
pumping at this rate. Because drawdowns vary directly with dis-
charge, drawdowns for greater or lesser rates of discharge can be com-
puted from these curves. For example, the drawdown 100 feet from
a well at the Lansing Smith Steam Plant discharging at 500 gpm
would be 24 feet after 100 days of pumping. If the well had discharged
at 100 gpm for the same length of time, the drawdown at the same
distance would have been only one-fifth as much, or about 5 feet.
The graph of drawdowns along a line of 10 wells, spaced 2,000 feet
apart, at a rate of 200 gpm, are shown in figure 15. The values used
to determine this profile were obtained by summing the overlapping
drawdowns for each well in the line as read from the 100-day curve for
the Long Beach test (fig. 14). Similar graphs can be computed to de-
termine the drawdown that would result from different pumping rates
or different well spacings (Lang, 1961, Theis, 1957).
The cone of depression in the vicinity of a well or a well field
being pumped at a constant rate will eventually stabilize if a balance








FLORIDA GEOLOGICAL SURVEY


DISTANCE, IN FEET, FROM DISCHARGING WELL


LANSING SMITH STEAM PLANT TEST

Figure 14. Graphs showing theoretical drawdowns in the vicinity of wells being
pumped at a constant rate for selected periods.






REPORT OF INVESTIGATIONS NO. 41


THOUSANDS OF FEET
25 20 15 10 5 0 5 10 15 20 25
0

50 ------ -- ---- --- --- ---
50

So 100o


S Computations based on

200 T= 4,000gpdft. _
S= .0005

250 __-.
Figure 15. Theoretical drawdowns along a line of 10 wells after 100 days of
pumping at a rate of 200 gallons per minute at each well.

is established between the amount being pumped and the amount
moving to the well, either through a decrease in natural discharge or
an increase in natural recharge. Water-level records (p. 33) in the
well field of the International Paper Company show that the cone of
depression in that well field had stabilized by 1951 as a result of
controlled pumping.
WATER USE
Water planners should know how much of the available water is
being used and the areas from which it is taken. Oftentimes, the
amount of water available in an aquifer is ascertained by determining
how much is being withdrawn and by measuring the effects of this
withdrawal on the water levels in the aquifer. For example, the low
water levels in the Floridan aquifer prior to February 1964 were near
the level where dewatering of the aquifer would begin near the cen-
ters of heavy pumping.
The major uses of water within the Econfina Creek basin are rec-
reation, manufacture of paper products, and public and domestic sup-
plies. An undetermined though relatively small amount is used for
irrigation. More than 80 named lakes, inland bays that cover over 100
square miles, and the larger streams are used for recreation.
Information was collected on the various municipal and industrial
uses of water within the basin, except recreation, in order to estimate
the total amount being withdrawn. Data on principal water-supply
systems are given in table 2.










'I'TAIL 2. 1t4'ordl of watlr IIpply sy .tystin in tihe Ic(onflna Crwek nasin ar~a.


Aquifer: F, Floridan; W, wator table.

Treatment: A, aeration; C, coagulation; CI, chlorination;


F, floculation; I1, recarlonation;
S, softening; St, stabilization,


Number Well.pump
of wells Aquifer capacity
(gpm)


Ground Elevated
storage storage
(gallons) (gallons)


Capacity of
stand by Yearly pumpago
Treatment well pump milliona of
(gpm) gallons)


Panama City:
St. Andrew Plant



Millville Plant

Lynn Haven

West Panama City Beach
Long Beach
Tyndall Air Force Base


U. S. Navy Mine Def. Lab.
Woodlawn Subdivision
Hathaway Water System
Mexico Beach Water System
Gulf Power Co. Water Plant
International Paper Co.


8 F 285 to 500 1,000,000 300,000 A, St, CI, 8


430 to 500
e175
750
700
500
328
300 to 600


300
e350
60 to 100
735


n3) to 770


400,000

100,000

reservoir


240,000
125,000
84,000
45,000
20,000
100,000
250,000


100,000

250,000
100,000
500,000
150,000
50,000



100,000
400,000


A, St. CI, S
A, St, CI, S
A, C1

A, Cl
Cl
A, C, R, CI, F, S
St

A, CI, St
A, C1
Cl
A, Cl


800 866.8 Ground storage 2 tanks
500,000 each.
Elevated storage for
Panama City system 3
tanks 100,000 gal, ea.


600


350
500,
328
1,500


630
e350


735


660,2

05.5

84.9
76.1
1,017


78
31.6
12.7
24.4


5,478.5
5,478.5


2 tanks 350 each



2 tanks 250,000 each


2 tanks 42,000 each


4 tanks 5,000 each


Not in operation
As of Jan, 31, 1964
began receiving water
from Deer Point Lake


e Estimated


Location


Remarks


____ _I_





REPORT OF INVESTIGATIONS No. 41


Prior to February 1964, no surface water was being withdrawn and
ground water was being used at the rate of 25.2 mgd. Of this amount,
22.7 mgd came from the Floridan aquifer. In February 1964, when
the International Paper Company began using surface water, ground-
water use in the basin was reduced to about 11 mgd.
The International Paper Company, the major industry in the
area, is the largest user of water. Prior to February 1964, the water
used by this company was supplied by wells. About 13.5 of 15 mgd
was pumped from the Floridan aquifer and the remainder was pumped
from the watertable aquifer. Water used by this industry prior to 1964
is shown by graph in figure 16. In February 1964, this company started
receiving water from Deer Point Lake at the rate of about 30 mgd.
There are nine public water-supply systems in the area. All water
produced by public water-supply systems is pumped from the ground.
The rate of pumping varies from 6.7 mgd during low demand periods
of fall and winter to 12.9 mgd during peak demand periods of spring
and summer. Areas served by these systems and locations of the wells
are shown in figure 17.
Water use has increased with population (fig. 16). Also the per
capital consumption in Panama City has increased from 70 gpd (gal-
lons per day) to 80 gpd during the 10-year period, 1950-60. This
figure is based on the average daily pumpage of the Panama City
water system and the population of the area supplied by this system.
Only a small part of the water pumped by the city is supplied to indus-
try and other non-domestic users. Also, there are a number of private
irrigation wells in the city. Partly for these reasons the per capital con-
sumption is below the more normal rate of about 150 gpd per person
that is reported in other areas.
Nearly 18,000 persons live in areas not served by public water
systems. At a per capital consumption of 80 gpd this would amount to
about 1.4 mgd used for rural domestic purposes.


WATER HIGH LIGHTS OF THE BASIN
DECLINE OF WATER LEVELS IN THE PANAMA CITY AREA
GENERAL STATEMENT
From 1908 to 1964 water levels in the Floridan aquifer near Pan-
ama City were lowered about 200 feet in the centers of major well
fields. This decline represents the difference between the reported
static water level of 16 feet above mean sea level in the first well
drilled in 1908 and the pumping water levels in the major well fields







30 FLORIDA GEOLOGICAL SURVEY

p i I ; i il Il
i I Ia i I
IIJT NA I t I I

PAPER COMPANY i
.5o00 ; .' ; --
S( I I i I "


a I I I I I I
I A I






t 2I l A I I I
a a t at
S I







o I l I I
I I II I


I I I; I' I
I i a I
OAO I I i a I I





0 00 I
0 1 I I I I
















gure 16. Graphs of water use and population in the Panama Cit area.
SI

I I l






aTY I I L I "DAIRFORCE
S 0 ,1 1 I ',1
S: I I 1950 I 5 0






Fixur 16 Gahofwtr us an pouato intePn itar.






REPORT OF INVESTIGATIONS No. 41


Figure 17. Map of the Panama City area showing the location of water wells
for each water system and the area supplied by these systems.

in early 1964. In January 1964 one well field consisting of 21 wells
was shut down. The water levels in this well field recovered 163 feet
within 51 days. Figure 18 shows the approximate piezometric surface
in 1908 under natural water conditions. The piezometric surface in
1962 (fig. 13) shows the lowered water levels caused by pumping
since 1908.

HISTORY OF GROUND-WATER DEVELOPMENT
The first deep well reported in the Econfina Creek basin was com-
pleted in 1908 for an ice plant in downtown Panama City (Sellards,
1912). In 1909 Panama City drilled a city supply well at the location
of the old National Guard Armory. In the same year another well was
drilled near the present water tank on Eleventh Street to supply
St. Andrew.






FLORIDA GEOLOGICAL SURVEY


Figure 18. Map showing the approximate piezometric surface of the Floridan
aquifer in the Panama City area in 1908.

From 1908 to 1930 there was not enough water withdrawn by
pumping to noticeably affect water levels in the Floridan aquifer.
However, in 1930 the International Paper Company developed a well
field in the Millville area, consisting of seven wells in the Floridan
aquifer and three wells in the water-table aquifer. Three of these wells
in the Floridan aquifer flowed at the time of drilling and the static
levels in the others were about 20 feet above mean sea level (from 8
to 20 feet below land surface). The original test well for this supply
reportedly flowed at a rate of 60 gpm and, when pumped at a rate of
700 gpm, the water level dropped to 55 feet below land surface. A cone
of depression developed in the piezometric surface of the Floridan
aquifer as water was withdrawn. Static water levels in wells drilled
in 1935 were more than 50 feet lower than in the original wells drilled
in 1930. By 1937 the water level near the center of the well field re-
portedly was 104 feet below mean sea level, a decline of 124 feet from
the time pumping began. This cone of depression expanded as the
paper company extended their well field eastward and northward.
A program was initiated by the paper company to protect their
water supply. Four wells near the original center of pumping were






REPORT OF INVESTIGATIONS NO. 41


abandoned to decentralize pumping and to thus prevent excessive
drawdowns which were limiting production of water. The control of
water levels was considered necessary also as a precaution against
salt-water encroachment. Pumping from each of the other wells in the
field was regulated for the most efficient production from the aquifer
within the cone of influence. Water-level records, shown in figure 19,
of an abandoned well about one mile from the center of pumping show
the effectiveness of this program.

-J
W 75
SWater level affected by
S80 near-by pumping wells
Ui
S85-
S90
1 95.




U 115-
120 -
- 125
3 1951 1952 1953 1954 1955 1956 11957 11958 11959 11960 1961 1962 11963

Figure 19. Graph of water levels in observation well 008-537-332 near the center
of the International Paper Company well field for the period 1951 to 1963.

In January 1964 the paper company was producing water from 21
wells in the Floridan aquifer and 10 wells in the water-table aquifer.
These wells were pumping an average of 15 mgd, of which about 13.5
mgd were from the Floridan aquifer. At this time the water level in
the Floridan aquifer under pumping conditions was about 184 feet
below mean sea level at the center of pumping and 100 feet below
mean sea level on the east edge of the field. These represent draw-
downs of about 200 to 120 feet since pumping began in 1930. Although
this is a considerable drawdown, the pumping level in the field was
essentially stabilized at this level. Minor fluctuations (fig. 19) were
caused in part by seasonal variations in pumping from neighboring
well fields. The major recoveries shown on this graph indicate periods
when pumping from wells near the observation well was stopped tem-
porarily or when pumping from the entire field was stopped.






FLORIDA GEOLOGICAL SURVEY


At the end of January 1964 when the paper company began using
water from Deer Point Lake, all of the wells that had been pumping
from the Floridan aquifer were shut down. In four days water levels
in the aquifer recovered from about 200 to 83 feet below mean sea
level near the old center of pumping and from 105 to 58 feet below
mean sea level on the east edge of the field. After 51 days, water levels
had recovered to 21 feet below mean sea level near the center and to
about mean sea level on the east edge of the field.
In 1936 Panama City built a water plant in the Millville area.
This plant was initially supplied by wells in the water-table aquifer,
but later supplied by wells drilled into the Floridan aquifer. In 1955
a well drilled into the Floridan aquifer had a water level of 63 feet
below mean sea level. In October 1962, after all pumps were shut off
for a period of 6 hours, the water level in this well was 72 feet below
mean sea level, a net decline of 9 feet from 1955 when the well was
drilled. The decline in water levels is attributed to pumping from this
well field and from the nearby paper company well field.
Another public water-supply system for Panama City was con-
structed in the St. Andrew section during late 1942 and 1943. When
the first of the original seven wells were drilled the water level in the
Floridan aquifer stood at about mean sea level. By mid-1943, when
the last of the seven wells was drilled, pumping from the first wells
had lowered the water level in the vicinity about 20 feet. In October
1954, when an eighth well was added to the well field, the pumping
level had been lowered to 67 feet below mean sea level. This drawdown
of 67 feet resulted from pumping at an average rate of 1.6 mgd.
Measurements of water-level in the St. Andrew well field in Octo-
ber 1962, after a 6-hour recovery from pumping, showed the water
level to be 87 feet below mean sea level near the center of the field.
The additional drawdown of 20 feet in the center of the field during
the 9-year period from 1954 to 1962 represents the effect of pumping
at 2.0 mgd, an increase of 0.4 mgd in the average daily pumping rate.
A well field consisting of four gravel-packed, screened wells in the
water-table aquifer was constructed at Tyndall Air Force Base in
1941 to supply water for the base, then under construction. It was
found that this aquifer would not supply sufficient water so it became
necessary to develop a supply from the Floridan aquifer. When the
wells were drilled in the Floridan aquifer the water level stood about
8 feet above mean sea level. By 1946 the water level had lowered to
about 10 feet below mean sea level. In 1961 pumping levels in the
Floridan aquifer were as much as 82 feet below mean sea level near






REPORT OF INVESTIGATIONS No. 41


the center of the well field. The cone of depression which had been
developing in this field was clearly established by 1961.
The maps of the Panama City area showing the piezometric sur-
face of the Floridan aquifer, figures 13, 18, and 20, illustrate the effect
of development of water from this aquifer. The piezometric surface in
1908 (fig. 18) is indicative of the general conditions in the area up to
about 1930. By 1947 the 4 principal well fields were producing enough
water to develop sizeable cones of depression in the piezometric sur-


Figure 20. Map showing the piezometric surface of the Floridan aquifer in the
Panama City area in April 1947.

face (fig. 20). A comparison 6f piezometric surfaces in figures 13 and
20 clearly shows that increased pumping from expanded well fields
has extended the cones of depression and has lowered water levels
generally throughout the Panama City area during the period from
1947 to 1962.
THE DEADENING LAKES
The Deadening is a group of lakes in the lower end of a closed
creek basin-'in the southeastern corner of Washington County, as
shown in figure 21. These lakes receive the surface drainage from the







FLORIDA GEOLOGICAL SURVEY


Figure 21. Map of White Oak Creek basin in southeastern Washington County
showing The Deadening area.

White Oak Creek basin of 44 square miles and seepage from the water-
table aquifer which underlies the surrounding sand hills. They lose
water only by evapotranspiration and percolation to the underlying
limestone formation. Gully Pond, Wages Pond, Hamlin Pond, Still
Pond, and Hammock Lake are joined at an elevation of 70 feet and
their combined surfaces cover 3,640 acres. Porter Lake is connected
to the other lakes at high water through Swindle Swamp and Black
Slough. At an elevation of 70 feet, Porter Lake covers 930 acres. The






REPORT OF INVESTIGATIONS No. 41


area of these lakes and Swindle Swamp is about 5,000 acres at an
elevation of 70 feet.
The variances in the supply of water and the constant drain
through the ground cause wide fluctuations in stages of The Dead-
ening lakes. In 1950, as a result of flood waters, the lakes reached an
elevation of about 70 feet. Due to the dry weather for a period of
several years (fig. 4) some of the lakes were dry and others had re-
ceded to elevations as low as 40 feet by 1956. Above average rains in
the late 1950's caused some of the lakes to recover to normal levels.
Since 1960 lake levels have again receded.
The Deadening lakes have a considerable recreation potential.
However, the wide ranges in lake levels prevent the potential from
being realized.
The Washington County Development Authority has proposed a
plan to divert water from Econfina Creek to these lakes at the rate
necessary to stabilize them at an elevation of 70 feet above mean sea
level. The diversion from Econfina Creek would be at a point just
downstream from Tenmile Creek, by way of a diversion canal to
Porter Lake. After Porter Lake is filled, water would overflow through
Swindle Swamp and Black Slouth to The Deadening lakes.

GEOLOGIC AND HYDROLOGIC SETTING
The Deadening lakes are located in the sinks and lake physio-
graphic division (fig. 2). They originated by the collapse of the over-
lying sands and clays into cavities caused by solution of the limestone
of the Floridan aquifer. Where solution and collapse activity has
breached the confining layer, figure 22, there is a loss of water from
the lakes to the Floridan aquifer.

WATER LEVELS
Levels of the Deadening lakes have been as high as 70 feet and as
low as about 40 feet above mean sea level. A topographic map made in
1950 shows an elevation of 70 feet for Porter Lake, and shows the
Deadening lakes to be completely covered with water at an elevation
of 69 feet. Based on flood marks, about 70 feet is the highest elevation
that the lakes have reached. The bottoms of Hammock Lake and
Porter Lake are at an elevation of about 40 feet. Hammock Lake was
reported to have been dry in 1956.
Figure 23 shows that lake levels have varied from a high of 68.3
feet in Porter Lake to a low of 44.2 feet in Gully Pond during the
period from'1961 to 1963. Lake levels declined throughout most of
that period. In mid-1963 the lakes began responding to rainfall as






FLORIDA GEOLOGICAL SURVEY


-,












Figure 22 Geohydrologic scions through the White Oak Creek basin,




lakes and the aquifer.
: *
3 AccA







l ccli..., o Si c'o












S 'ogh (fig. 21). The flow from Still Pond is to Hamlin Pond by way1
of subsurface channels. These subsurface channels are evidenced by
Figure 22 Geohydrologic sections through the White Oak Creek basin,
southeastern Washington County.

shown by the graphs in figure 23. The similarity of the graphs of lake
and ground-water levels indicates hydrologic continuity between the
lakes and the aquifers.
Flow from White Oak Creek enters Swindle Swamp and separates,
part going to Porter Lake and part going to Still Pond through Black
Slough (fig. 21). The flow from Still Pond is to Hamlin Pond by way
of subsurface channels. These subsurface channels are evidenced by
sink holes through which movement of water can be seen. Hamlin
Pond overflows to Hammock Lake. Wages Pond receives surface
drainage from Howard Swamp and overflows to Gully Pond. Ham-
mock Lake and Gully Pond are at a lower stage than the other lakes
because they receive surface flow only when the other lakes overflow.
A comparison of the recessions of lake levels to the expected evap-
orational losses indicates the lakes lose water to the underlying Flor-
idan aquifer. The level of Clarks Hole, an arm of Hamlin Pond,
receded seven feet from August to December 1962. Below a stage of
55 feet, Clarks Hole is separated from Hamlin Pond and the shore
line is below the line of vegetation, which eliminates most transpir-
ational losses. The major water losses from Clarks Hole below a stage
of 55 feet are evaporation and downward leakage. During the 5-month
period that water levels in Clarks Hole declined seven feet, the evap-
orational loss was about 2 feet, based on pan evaporation records







REPORT OF INVESTIGATIONS No. 41


1961 1962 1963
70 JIFIMIAIMJJASOND AMIJJIAISIOINIDJIFIMIAIMIJIJ IASONID
70 w 12-

(2 miles north of Porter Lake)









N.Porter Lake) (water'table aqufer) o
W 68 Z
> 26
w

66 2 .


w p
COJ64
Well 030-535-422b ,
SPorter Lake n (wateForableaquifer)






o t S o (Flodan aquifer) 0-5'




Sages

w

Clarks Hole- /Ik








48 Le
zn P) G03-535-42
52 (Floridan aufer)







lakes. H

46




1961 1962 1963

Figure 23. Graphs of water levels and rainfall in the vicinity of the Deadening
lakes.






FLORIDA GEOLOGICAL SURVEY


collected at Woodruff Dam by the U. S. Weather Bureau. The re-
maining five feet represents leakage to the ground. Clarks Hole re-
ceived no inflow during this period. Some of the other lakes did, which
minimizes the apparent losses shown by graphs in figure 23.
The Deadening area received about 11 inches of rain in July 1963,
of which 8 inches fell during the last 10 days of the month. These
heavy rains caused moderate rises in the lake levels and the piezo-
metric surface of the Floridan aquifer. The ground-water level and
lake levels, in general, showed about the same amount of rise, from
2 to 5 feet. The water level in Clarks Hole rose about 12 feet as a
result of overflow from Hamlin Pond.
Water in the Floridan aquifer moves in the general direction of the
slope of the piezometric surface (fig. 13). Water moves to the center
of The Deadening area from the northeast, and moves radially from
The Deadening area toward Econfina Creek to the southeast, the
Gulf of Mexico to the south, and Pine Log Creek to the southwest.
Wells in The Deadening area showed larger gains during the rise
of July 1963 than wells outside the area. This indicated that the
Floridan aquifer gains water indirectly from rainfall more rapidly in
The Deadening area than in the surrounding area.
Water diverted to The Deadening lakes would move from the
lakes to the Floridan aquifer at a rate proportional to the head
between the lake surfaces and the piezometric surface of the aquifer.
Raised lake levels could increase this head and cause more water to
enter the aquifer. If the lake levels are maintained at a constant ele-
vation, the head that will be established depends on the ability of the
Floridan aquifer to transmit water away from the area.

FLOW OF ECONFINA CREEK
Information on the flow of Econfina Creek was obtained to de-
termine the amount of water available at the proposed point of diver-
sion and to determine what effect diversion would have on streamflow.
The proposed point of diversion is just east of the north end of
Porter Lake, about midway of the basin. The drainage area of Econ-
fina Creek above the proposed point of diversion is about 67 square
miles. The average flow at this point was estimated to be 90 mgd.
Minimum flow at the point of diversion is the important criterion
in determining the available flow. The greatest amount of water will
be needed in the lakes when the creek flow is lowest. A minimum flow
of 30 mgd was estimated on the basis of three discharge measure-
ments and the relation of these measurements to the long-term flow
record at the Bennett gaging station. This minimum flow probably will






REPORT OF INVESTIGATIONS No. 41


not occur more often than once every 15 to 20 years, and then prob-
ably will not persist for more than a few months. A flow of 36 mgd
was measured at the point of diversion on May 27, 1963, during a
period of extreme low flow.
A dam to create a retention reservoir along Econfina Creek is being
considered. The main purpose of this reservoir would be to raise the
water level in the creek and make gravity flow to Porter Lake possible.
There would be a usable storage in this reservoir between elevations
80 and 95 feet of about 4,000 acre-feet. This amount of storage would
provide 10 mgd for a period of four months. This, added to the natural
flow of the creek, would assure a minimum flow of about 40 mgd. A
flow of 40 mgd would supply about 0.7 of a foot of water per month
on the 5,000-acre lake area.
If diversion from Econfina Creek is at a rate of 30 mgd, the stream-
flow just downstream from the point of diversion would be almost
depleted during periods of low flow. This effect will diminish down-
stream. Diversion of 30 mgd would reduce the flow below Gainer
Springs about 15 percent. The width of the stream at this point would
not be affected, and the depth would be reduced from a usual 4.5 feet
to about 4 feet. Figure 24 shows, pictorially, the effect on stream-
flow if 30 mgd were taken from the creek during low flow. A diversion
of this amount is a negligible part of the total flow into Deer Point
Lake and would have no adverse effect on this water supply.
Some of the diverted water would be returned to Econfina Creek
by an increase in the flow of artesian springs. The higher spring flow
would result from an increase in the piezometric slope caused by
recharge to the Floridan aquifer from the lakes.

SPRINGS
The artesian springs along Econfina Creek are located downstream
from a point just east of Porter Lake. Spring flow to the creek in-
creases downstream to a maximum near the Washington-Bay County
line. Below Gainer Springs it diminishes and there is little, if any,
spring flow to the creek below the gaging station near Bennett, as
shown on the flow chart in figure 25.
Spring water flows into Econfina Creek directly through the
stream bed, from the base of rock bluffs, and from short spring runs
about a quarter of a mile in length. The spring water emanates from
the Floridan aquifer where Econfina Creek has breached the over-
lying, confining clay layer. Figure 22 illustrates the hydrologic rela-
tionship of the aquifer with the creek. Figure 13 shows the pattern
of flow towards the springs.







FLORIDA GEOLOGICAL SURVEY


0 2 4 Wal
I t ---


V Od- Wf > I / NO SPW WSTIEAM FOWN HIE




FLOW CHART
4 229 gd otal with of treaom represents flow with no diversion.
U 30 mgd diverted
Streamflow afte r 30 rg diverted
4 Flow--moeasing poilt
0 400 rgd
Flow scola






Figure 24. Flow chart of Econfina Creek during the low-water period of May
1963 showing the effect on streamflow if 30 mgd were diverted at the proposed
dam site.


It was possible to make direct measurements of the flow from
Blue Springs and Williford Springs. Flow from Gainer Springs was
determined by the difference in streamflow measurements above and
below the group. Other spring flow, which could not be measured,
enters the creek along its bed and banks.
The amount of flow attributable to spring flow was calculated at
the Bennett gaging station utilizing electrical conductivity measure-
ments of the water. Pure water is a poor conductor of electricity but
mineral matter dissolved in water consists of charged particles which
will conduct an electrical current. The amount of current that a water
will conduct is an indicator of the amount of dissolved minerals in
the water. The measurement of the electrical current conducted by







REPORT OF INVESTIGATIONS No. 41


FLOW CHART
M Spring flow
E Non-spring flow
0 300mgd
Flow scale


1 0 1 2 3 4 5mi.

Figure 25. Flow chart of Econfina Creek showing spring flow.


water is expressed as specific conductance in units of micromhos.
The specific conductance of the water from the springs along
Econfina Creek ranged from 95 to 150 micromhos. Water in the creek
above the area of spring flow ranged from 14 to 26 micromhos. Aver-
age specific conductance values of 114 micromhos for spring water
and 20 micromhos for non-spring water were used in the calculation
of spring flow.
i /







44 FLORIDA GEOLOGICAL SURVEY

Water at the Bennett gaging station was considered to be a thor-
oughly mixed combination of spring water and non-spring water.
Flow at the Bennett gaging station, attributable to springs, was
calculated from the formula:

Kb -K
Qs K -K Qb
s n
where: Q is spring flow

Q, is streamflow at Bennett
K is specific conductance of spring water
K is specific conductance of non-spring water
Kb is specific conductance of the mixture

Figure 26 shows the flow of Econfina Creek during non-flood periods
and that portion attributable to springs for 1963. Spring flow con-
tributes about two-thirds of the total flow of Econfina Creek.






00 5 800






3i
400 400


300 500







5-
CALCULATED SPRIM FLOW






4AM FED MAR APR M"t JPE AUI AU6 SEPT OCT NOV DEC
Figure 26. Graphs of streamflow, spring flow, and specific conductance for
Econfina Creek near Bennett in 1963.






REPORT OF INVESTIGATIONS No. 41


DEER POINT LAKE
Deer Point Lake (fig. 1) was formed on November 17, 1961, by
construction of a salt-water barrier across North Bay at Deer Point.
The lake was planned to serve as a source of fresh water and to pro-
vide recreational facilities. It covers 4,700 acres, most of which was
formerly a part of North Bay, and stores approximately 32,000 acre-
feet of water at a level of 4.5 feet above mean sea level, the elevation
of the dam.
The lake is stabilized at an elevation of 5.0 feet above mean sea
level. The potential fresh water supply is approximately 650 mgd,
the average flow through the lake to North Bay. In February 1964
the only withdrawal from Deer Point Lake was the 30 mgd by the
International Paper Company.
A study of the lake hydrology in the period immediately before
and for several months after the dam was constructed (Toler, Mus-
grove, and Foster, 1964) was made to determine the rate of freshen-
ing and the effect the lake would have on the water-table aquifer.
Figure 27 shows the rate of freshening of the lake in terms of the
number of times the inflow of fresh water would have filled the lake.
Plotted in this manner, the graph enables a prediction of the rate of
freshening of any similar lake if the volume and concentration of lake
water and inflowing water are known (Toler, Musgrove, and Foster,
1964). When the barrier was completed on November 17, 1961, the
lake was about half full and the chloride concentration was about
7,400 ppm. Flow over the spillway began on November 29, 1961, and
the chloride concentration had been reduced to 3,700 ppm. In mid-
February 1962 the chloride concentration was about 200 ppm.
When the barrier was completed, water levels in the lake and in
the water-table aquifer adjacent to the lake rose rapidly, as shown
in figure 28. An immediate effect of the rise in the lake level was to
reverse the water-table gradient near the lake so that water moved
from the lake into the aquifer. This is evidenced by the rise in chloride
content in water from well 015-535-232, 45 feet from the lake. Water
in wells 100 feet or more from the lake showed no change in chloride
content. When the water table adjusted to the new lake level, the
water movement was again toward the lake and the high chloride
water was flushed from the aquifer.

SUMMARY
In general, the hydrologic system through which water moves in
the Econfina Creek basin is similar to most basins in northwest
I







46 FLORIDA GEOLOGICAL SURVEY


1961 | 1962 I 1963
V 1 EC I JAN FEB MAR APR MA UN JUL AUG SPT OCT NOV DEC JAN



4500 -



4000 -



3500

z2
0
_ 3000 Vis volume of fresh woler that has flowed into Joke
:. since spillway overflow began
lii
a-
2V,- volume of the loke at spillway elevation
a 2500



. 2000



U 1500



1000 -



500 -



I 2 3 4 5 6 7 8 9 10 II 12 13 14 15 16 17 18 19 20 21


Figure 27. Graph showing the relation of chloride in water in Deer Point Lake
to fresh water inflow.


Florida. That is: (1) rainfall is the source of all the water even though
some falls outside the basin and moves into the basin underground;
(2) the surface materials are highly porous, unconsolidated sands;
(3) it is underlain by the artesian Floridan aquifer; and (4) water
leaves the basin by streamflow, evaporation, transpiration, under-
ground flow to the ocean and other basins, and by consumptive use.
There are four physiographic divisions within the basin that
affect the surface drainage and the water storage, both above and







REPORT OF INVESTIGATIONS No. 41


4.0 Well 016-535-342b







SWail 015-535-232
Wale( level



S3.0 2000


2-0 1 3000





NOV. DEC. JAN. FEr MAR. APR. MAY JUNE JULY AUG SEP. OCT. NOV. DEC. JAN. FEB. MAR. APR MAY JUNE
961 1962 963
Figure 28. Graphs showing the rise of water levels and change in chloride
content of ground water after construction of Deer Point Dam.


below the ground. These are the sand hills, sinks and lakes, the flat-
woods forest, and the coastal sand dunes and wave-cut bluffs.
The surface materials on which the physiographic features have
developed are generally very porous, permeable sands which are from
0 to 140 feet thick. These sands form the water-table aquifer. A con-
fining layer, or aquiclude, of sandy clay and clayey shell material
separates the water-table aquifer and the Floridan aquifer.
In the bay area and along the gulf coast there are two artesian
aquifers. Here the formation that forms the aquiclude is thicker than
it is to the north and is overlain and in part underlain by some shell-
hash beds which contain water under artesian pressure. Water pro-
ducing zones in the shell-hash beds above the aquiclude are termed
the secondary artesian aquifer.
The Floridan aquifer underlies the entire basin below the aqui-
clude. It is composed of limestone formations that include the lower
units of the shell-hash beds and are as much as 1,200 feet thick.
The basin receives an average of 58 inches of rainfall per year.
A partof the rainfall is absorbed by the porous surface sands and a
part moves directly into the streams. Some water from the sands
moves to the streams and maintains flow during periods of no rain-
(I


Deer Ptint. ..-- e*-
7 K Well 015-535-232






FLORIDA GEOLOGICAL SURVEY


fall. Water also moves from the sands downward to the Floridan
aquifer but the amount diminishes toward the southwest because the
aquiclude becomes thicker. Movement within the Floridan aquifer
is generally southward with some water flowing into the channel of
Econfina Creek by way of artesian springs.
The transmissibility of the Floridan aquifer varies within the
basin, and is lower than the transmissibility of this aquifer in most
other areas in Florida. Coefficients of transmissibility range from
2,000 to 30,000 gpd/ft.
The water in the lakes and streams differs little in mineral con-
centration from rain water because of the relative insolubility of the
surface materials. Two areas of exception are where Econfina Creek
receives artesian spring flow and near the mouth of streams that
empty into salt-water bays.
The mineral content of water from the water-table aquifer gener-
ally ranges from 10 to 50 ppm, and that of water from the secondary
artesian aquifer from 80 to 150 ppm. The mineral content of water
from the Floridan aquifer is higher than that from the other two
aquifers. Mineral concentrations in water from this aquifer show
increases in all constituents from the northern part of the basin to
the southwest.
Some salt-water intrusion was detected in the water-table and
the secondary artesian aquifers adjacent to the bays and Gulf. The
confining clay layer overlying the Floridan aquifer in the coastal
and bay area is sufficiently impermeable to prevent leakage of water
from the overlying aquifers. Water in the Floridan aquifer in the
southern part of the basin is apparently a mixture of fresh water and
residual saline water.
Streamflow to the bays is at an average rate of about 960 mgd
which for a year would amount to 40 percent of the average annual
rainfall of 58 inches. About 650 mgd flows through Deer Point Lake
into North Bay, and another 30 mgd flows into North Bay below Deer
Point Dam. East Bay receives a flow of about 210 mgd and West Bay
about 70 mgd. Most of the streams have sufficient flow to be a poten-
tial water supply. During periods of minimum flows there is more
than 10 times as much fresh water flowing into the bays than is being
withdrawn in the basin. Econfina Creek, by far the largest stream
in the basin, has an average flow of 355 mgd.
Low runoff from the southern part of the basin results from poor
drainage features of the flat-woods forest. Drainage in the sinks and
lakes division is mostly internal. High base flow due to seepage from
the porous sands causes high runoff in the sand hills division.







REPORT OF INVESTIGATIONS NO. 41


There are about 80 named lakes in the basin, most of which are
in southeastern Washington County. Deer Point Lake, a fresh-water
reservoir covering 4,700 acres, is the largest. Porter Lake has a sur-
face area of 930 acres and is the largest natural lake.
The major uses of water within the basin are for the manufacture
of paper products, for public and domestic supplies, and for recrea-
tion. Prior to February 1964 no surface water was being withdrawn
and ground water was being used at the rate of 25.2 mgd. Of this
amount, 22.7 mgd came from the Floridan aquifer. The International
Paper Company was the largest user of water, using about 13.5 mgd
from the Floridan aquifer and about 1.5 mgd from the water-table
aquifer. In February 1964 this company started receiving water from
Deer Point Lake at the rate of about 30 mgd. Ground-water use in
the Panama City area was reduced to about 11 mgd.
The first well in the Floridan aquifer was drilled in 1908. Later,
as the demand for water increased, more wells and well fields were
developed and water levels were lowered. By the end of 1963, when
water was being withdrawn at the rate of about 25.2 mgd, pumping
levels had been lowered as much as 200 feet near the centers of major
well fields. Pumping from the paper company well field, consisting
of 21 wells, was discontinued in February 1964 and water levels in
this field recovered 163 feet within 51 days.
The Deadening lakes in southeastern Washington County offer
considerable recreation potential. However, they lose water to the
ground at a high rate causing wide fluctuations in stage and this
prevents their full potential from being realized. The Washington
County Development Authority has proposed a plan to divert water
from Econfina Creek to stabilize these lakes at an elevation of 70
feet. The diversion from Econfina Creek would be at a point just
downstream from Tenmile Creek where the minimum flow was esti-
mated to be 30 mgd. The proposed plan calls for a detention reservoir
on Econfina Creek to raise the water level and make gravity flow
through a diversion canal possible. The storage in this reservoir,
added to the natural flow of the creek, would provide a minimum
flow of 40 mgd which would supply about 0.7 of a foot of water per
month on the 5,000-acre lake area.
Water leaks from the lakes to the Floridan aquifer at a rate pro-
portional to the head between the lake surfaces and the piezometric
surface of the aquifer. If the lake levels are maintained at a constant
elevation, the head that will be established depends on the ability of
the Floridan aquifer to transmit water away from the area.
If diversion from Econfina Creek is at a rate of 30 mgd, the stream






FLORIDA GEOLOGICAL SURVEY


just downstream from the point of diversion would be almost depleted
during periods of low flow. This effect will diminish downstream and
become almost negligible below Gainer Springs, a group of large
artesian springs just downstream from the Washington-Bay County
line. A diversion of 30 mgd is a negligible part of the total flow of
650 mgd into Deer Point Lake and would have no adverse effect on
this water supply. A part of the water diverted to the lakes would be
merely re-routed through the lakes into the ground and back to the
Econfina Creek through the artesian springs below the dam.
Deer Point Lake is a fresh-water lake formed November 17, 1961,
by a salt-water barrier across North Bay. It covers 4,700 acres and
stores about 32,000 acre-feet of water. The lake elevation is 5.0 feet
above mean sea level and fluctuates very little.
Artesian spring water flows from the Floridan aquifer into Econ-
fina Creek directly through the streambed, from the base of rock
bluffs and from short runs about a quarter of a mile in length. These
springs occur from a point just east of Porter Lake downstream to a
point near the Bennett gaging station. Springs contribute about two-
thirds of the flow of Econfina Creek.







REPORT OF INVESTIGATIONS No. 41 51

REFERENCES

Foster, J. B. (also see Toler, L. G.)
In Preparation Geology and ground-water hydrology of Bay County,
Florida.
Gunter, Herman (see Sellards, E. H.)
Hantush, M. S.
1955 (and Jacob, C. E.) Non-steady radial flow in an infinite leaky
aquifer: Am. Geophys. Union Trans., V-37, No. 6, p. 702-714.
Lang, S. M.
1961 Methods for determining the proper spacing of wells in artesian
aquifers: U.S. Geol. Survey Water-Supply Paper 1545-B.
Musgrove, R. H. (see Toler, L. G.)
Sellards, E. H.
1912 (and Gunter, Herman) The underground water supply of west-
central and west Florida: Florida Gzol. Survey 4th Ann. Rept.,
p. 116.
Shampine, W. J. (see Toler, L. G.)
Theis, C. B.
1935 The relation of the lowering of the piezometric surface and the
rate and duration of discharge of a well using ground-water
storage: Am. Geophys. Union Trans. p. 519-524, August.
1964 The spacing of pumped wells: U.S. Geol. Survey Water-Supply
Paper 1545-C, p. 113.
Toler, L. G.
1964 (and Musgrove, R. H., and Foster, J. B.) Freshening of Deer
Point Lake, Bay County, Florida: Am. Water Works Assoc.
Journal, V. 56, No. 8, p. 984-990.
1965 (and Shampine, W. J.) Quality of water from the Floridan aquifer
of the Econfina Creek basin area, Florida: Florida Geol. Survey
Map Series No. 10.