Title: QWIP manuscript entitled: "Salts of the Earth."
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00052724/00001
 Material Information
Title: QWIP manuscript entitled: "Salts of the Earth."
Alternate Title: Handwritten Note to L. M. Blain from SWFWMD enclosing the "QWIP" manuscript entitled: "Salts of the Earth."
Physical Description: 9p.
Language: English
Publication Date: June 24, 1975
Spatial Coverage: North America -- United States of America -- Florida
General Note: Box 5, Folder 16 ( QUALITY OF WATER IMPROVEMENT PROGRAM (QWIP) ), Item 17
Funding: Digitized by the Legal Technology Institute in the Levin College of Law at the University of Florida.
 Record Information
Bibliographic ID: UF00052724
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: Levin College of Law, University of Florida
Rights Management: All rights reserved by the source institution and holding location.

Full Text

Southwest Florida MEAGE RLY
Water Management District 4 TO

T C 44-9 /c

- --



A_)_ ()AUDIO

Sunset on Beach Long before the dawn of man on this earth, Nature was

at work molding the Florida landscape, creating hills, rivers

SA OC^ J and lakes, moving Florida's coastline back and forth,--and

setting the stage for one of Charlotte County's most serious

problems--salty ground water.V/

Map During Pleiocene times---about 2 million years ago-

warm tropical seas covered almost all of Peninsular Florida.

Only a few isolated islands---near present day Lakeland,

Haines City and the Green Swamp--- escaped inundation. WO,

Map Then came the Great Ice Age. As mammoth glaciers formed

S, i n both the northern and southern hemispheres, sea levels
.mL~s~ (Ya ^! ~th J A ^^ ^~&,AA.AO <3L CLA --.A o QCX-4 ,
"~ -"Ieclined. .In Florida as the seas retreated, lakes of salt
\ water and vast areas of salty ground water were left behind.

With the landscape now exposed to the effects of rainfall,

Sstreamflow and erosion, new layers of sand and clay were

washed down gradient to collect in shallow seas and on the

flatter portions of the land surface. &. js .

Map Eventually the world again turned warm; the glaciers

began to melt; sea. levels rose again and much of the Florida

peninsula was again underwater. Four times the cycle repeated
itself; four times the sea rose to cover portions of the land.

Each time it stopped short of the preceding high water mark

but each time it inundated Charlotte County and the southern

tip of the Florida peninsula.

The effect was permanent--if anything connected with
the earth and its geology can be permanent. By the time the

world had moved from the Pleistocene Epoch to the Recent

Epoch, by the time Florida's coastline had stabilized

roughly along its present boundaries, heavy deposits of salt

water had filled the deepest aquifers of Charlotte and

other South Florida counties IThis map shows us the areas

Map in which chlorides (saltS existed in significant quantities


in the top of the Floridan Aquifer at the end of the

Ice Age. W O Y

lhtil this century---a mere fraction of a second on

a geologic clock---this "problem" was no problem at all.

River Scene There was an abundance of fresh surface water available

and wells drilled into the shallower aquifers produced

a bountiful supply of potable water. So long as the

brackish water remained in the deep aquifers it was harmless. -

But 20th Century man---unaware of the consequences

of his actions, unaware of the various levels of aquifers
Truck Farm
in Charlotte County, unaware of the differences in water

quality in different aquifers and unaware of the causes of

salt water intrusion---upset the system. P o

(y Early settlers in Charlotte County---needing water with

which to irrigate their crops---drilled wells. Observing

5 L.L that, in general, the deeper the well the greater the

artesian pressure, they drilled their wells deep into those

aquifers most contaminated with chlorides, sulfates and

sulfides. Because the artesian pressure was so great,

pumps were unnecessary. Water---thousands of gallons per

day, even millions of gallons per day---poured freely from the

wells into the fields.

Those early settlers had no way of knowing what was

happening inside the well hole beneath the ground. They had

no way of understanding the effect those deep wells were

having upon the equilibrium between the brackish water in the

deeper aquifers and the sea waters in the Gulf and Charlotte

Harbor. They did not realize that they were inviting salt

water encroachment into their ground water resources and, at

the same time, allowing saline and sulfurous water to

contaminate the upper aquifers. They had no way of knowing

that they had set in motion a hydrologic process---actually

two processes---that would eventually contaminate the water

supply of their grandchildren. 7/ / Cl


Diagram #1 If we look at a cross sectional diagram of Charlotte

.County's geology, the impact of these deep wells upon the

water in the upper aquifers becomes clearer. As in most

parts of Florida, a layer of sand at the surface is under-

lain by a layer of clay. Beneath the clay, a massive strata

of limestone saturated with water extends down several

thousand feet. / /0j

Diagram #2 In Charlotte County, however, unlike most parts of the state,

several layers of clay or other impervious material intersect

the limestone, dividing it into separate aquifers or zones.

There are many local variations, but in general the

deeper the aquifer the greater the chloride and sulfide

contamination. Similarly, the deeper the aquifer the

greater the artesian pressure. /'7 0 ,--/

Diagram #3 When a well is drilled into the lower zones, if it were

properly cased all the way down, the problem with inter-aquifer

contamination would be minimal.

Most wells, however, were cased only down to the upper clay

bed or to the upper zone. Other wells, which were cased to

a greater depth, were cased with black iron and galvanized iron

substances that are attacked by hydrogen sulfide. Thus, over

the decades, these casings became corroded and water flows freely

in and out of the well bore. "

Here is what happens: V

Diagram #4 Water from the deep aquifer spurts up the well shaft. Because

it is under greater pressure than the upper aquifers, water

from the deep aquifer forces its way not only to the surface

but also into the upper aquifers. Thus, it contaminates them "

with greater concentrations of chloride, sulfate, and sulfide.//1

450 If we were talking of only a few such wells the regional
450 + l _/
Contaminated effect would not be particularly significant. However, more
than 450 such wells have been inventoried in Charlotte CountyA(AI..

and many more are known to exist. The cumulative effect oi this

many wells---ranging from 8 to 24 inches in diameter---pouring

contaminants into the upper aquifers year after year, decade

after decade has c- V,,I''.e ..n.
/ "

C oss Section / The movement of contaminated water from the deeper

s aquifers to the upper aquifers, however,;ls only one of the ill

effects of these wells. The other effect, closely related and

equally critical, is salt water intrusion. By reducing the

artesian pressure in the lower aquifers, these flowing wells

have invited the inland movement of salty water from the Gulf

of Mexico and from Charlotte Harbor. As a result, potable water

is mixed with sea water .i-'r_..i. _;

To understand how salt water intrusion occurs and

Cross Section 1 why, let's look at this cross section of Florida almost any-

where along the coast. Here the fresh water from the land

,urfaaeemeets the salt water from the Gulf. Because salt

water is heavier than fresh water, when the two meet, the fresh

water floats on top. The salt water forms a wedge underneath

the fresh water. l' ".'

A cross-section of the entire state with the Atlantic

Cross Section 2 Ocean on the east and Gulf of Mexico on the west shows that

salt water underlies the entire Floridan peninsula. Near the

coasts salt water is near land surface; at mid-peninsula, it

lies 1000 feet or more deep. /lf

Water, of course, seeks its own level. Thus, the salt

water beneath the-state is under pressure from both the Gulf

and the Atlantic to rise to mean sea level. Why doesn't it?

Because of the counter pressure exerted by the fresh waters

in the aquifer.t / 7
If, however, oe reduce the artesian pressure in the

Cross Section 3 fresh-water aquifer, the salt water beneath the ground will

rise proportionately. If we greatly reduced the artesian

pressure the salt water would rise to---or almost to---mean 2.

-------'-- sea level. '20 ... -

And how do we reduce artesian pressure? By taking water

from the aquifer at rates greater than Nature can replace it.~ j f/

Th6illustration, in terms of the entire peninsula, is

academic. But in Charlotte County and specific other locations

in the state, the problem is very real. For half a century in
1J )1
Charlotte County alone, wells have been taking more than H Of $

million gallons of water from the deep aquifers every day. The

cumulative effect upon pressures in the deeper aquifers---and thus

upon salt water intruion---has been enormous.v i ) a .. ,

.- *.- 5 -

The U. S. Geological Survey has compiled this Infor-
Map #1
ovation on Charlotte County's ground water resources. In

'Zone A, only the shallow aquifer is used. Water in the

deeper aquifers is too saline (salty) for human consumption. ,"

In Area B, north of Charlotte Harbor, the shallow
Mhp #2
aquifer contains water that meets state water quality

standards although it is high in iron. The uppermost

artesian aquifer here is too salty for human consumption

and of marginal quality for irrigation.

The second aquifer generally contains water suitable

for irrigation but not for humario*~nfpt Vt.

The third aquifer is about 150 feet thick. .Water

quality varies with the part of the aquifer tapped by

the well. In the deepest part of this aquifer, dissolved

solids content of the water exceeds 2,000 mg/l and is thus

unsuitable both for mats-3rim-i-'n and for many

irrigation purposes. -

In Area C, the shallow aquifer yields---with some
Map #3
localized exceptions---potable water.

In the eastern half of this area the first aquifer

also yields potable water. In the western half, however,

water from the first aquifer is not suitable for human

The second aquifer contains water that can be used

for irrigation but that is too salty for humans.

The 3rd, 4th and 5th aquifers in this area contains
-2 I/
water suitable for flood irrigation n .

In Area D, the water resources outlook is more
Map #4
promising. This area has undergone less development

than other parts of the county; it is located upgradient

from most of the contaminating deep wells.7 /

Water in the shallow aquifer here is low in chlorides

and sulfate. The first aquifer contains water that

apparently meets state health requirements. vt


The second aquifer contains potable water.

The third aquifer, in some places, also yields r water.

Oily in the 4th and 5th aquifers, is the water contam-

inated and it is---at least in some places---so salty that it

cannot be used even for irrigation. 2

If we bear in mind that few deep uncased wells were

drilled in Area D and then note the contrast between the

high quality water in the upper aquifers here and the poor

quality in the deepest aquifers, it becomes obvious that

the deep, uncased wells in other areas of the county are

the primary cause of water quality problems. Where man

has not created conduits for the water in the deeper

aquifers to flow into the upper aquifers, the upper aquifers

have continued to yield fresh and potable water. \

The solution, then, must depend upon shutting off this

QWIP flow of water between aquifers. That is the purpose of
Superimposed on
Map Operation QWIP---a major project of thr SWFWMD in, Charlotte

County. Hydrologists and technicians of the Water Management

District are now at work establishing a method through which

these contaminating wells can be plugged. The District's

Peace River Basin Board and Walt Wetterhall, District hydrologist

in charge of Operation QWIP, have emphasized that the contamin-

i. i- "-- .. eating wells must be plugged rather than capped. v

SWhen a well is capped---and many of the contaminating
Diagram #7
wells were capped years ago before being abandoned---

the cap shuts off the flow to the surface. It does not,

however, stop the flow from the lower aquifers into the upper

aquifers. 'In fact, by stopping the flow to the surface, the cap

increases the flow between aquifers.w f 3f .1' 1<

Plugging, on the other hand, stops the flow from the deep

aquifers and, thereby, allows flow where desired, from the upper
Diagram #8
aquifers to the surface. In this diagram, plugs have been placed

between the 3rd and 4th aquifers and between the 4th and 5th

aquifers. Thus, water from these deep aquifers can no longer

rise in the well bore. Water from the upper aquifers---water

of better quality---is now allowed to enter the well bore for use

by man. .
^ "
i/ -> f

With the aid of boom equipment, thejistrict'c n1..d crew lowers the

plugging materials -- pipe, and a long burlap tube with a leatherette boot

at the bottom -- into the well hole. The pipe and burlap L be pushed

to the precise location in the well hole where the plug is needed. -

Once the plugging material is in place, cement slurry is pumped down

the pipe to inflate the burlap tube and extrude through the plug material.

The leatherette at the bottom of the burlap provides protection and rigid-

ity against the well water flowing upward under artesian pressure -- often

gushing upward at 5-10 feet per second -- from blowing the plug back out. t--^

Once .the cement has filled the burlap tube, pushing it out to the

walls of the well hole, and then hardened, this is the result. The plug

-- often 15-20 feet in length -- stops the flow of contaminated water from

the deeper aquifers and allows free flow of better quality water from the

upper aquifers.\~ d



*- *, *

C. t

The diagram serves to illustrate the concept of

plugging a well. It fails, however to illustrate the

problems and challenges associated with the procedure, .

A more realistic illustration of a well bore would

Diagram #9 show not a round cylindrical shaft but a shaft riddled

with crevices and caverns. Before a plugging operation

can begin District hydrologists lower probes from a

Logger geophysical logger into the shaft. From the data collected

..-- by the logger they learn where the well bore widens, how fast

'1 water is flowing into the shaft from different aquifers,

Caliper log which aquifers are most seriously contaminated, and how deep

and.thick the various aquifers are. 3- ? /

From this information, the District staff determines

where the plug or plugs should be placedl7t

Then comes the challenge of getting the plugs in

the well shaft. Cement slurry is pumped down a small pipe into
Rig at Site lot)O
a burlap tube that is placed in the zone to be plugged./ The

plug must be pushed to the precise location in the shaft, filled

with cement and held in place until the cement hardens to

prevent this gushing water---often moving upward at 5-10 feet

per second---from blowing it back out.

Because of the problems encountered with well plugging,

because the old, conventional method of well plugging by

pumping cement into a well just doesn't work in many situations,

much of the work performed by the Water Management District

staff for operation QWIP experimental in nature. Although

several national companies build equipment for plugging huge

oil wells, apparently no one in this country has ever attempted

a water well plugging operation like QWIP. Consequently,

every aspect of QWIP- _g kTi. A

be designed and developed by District hydrologists, geologists,

engineers, welders, and mechanics.

But if Project QWIP presents its special problems and
QWIP superimposed
over water spigot challenges, it also presents an even greater reward- a bete-er

.-qual;-t water supply for this and future generations of Charlotte

Countians. 4/3

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