• TABLE OF CONTENTS
HIDE
 Front Cover
 Credits
 Table of Contents
 Foreword
 The Everglades problem
 Description of the Everglades...
 Soils of the Everglades
 Subsidence of peat soils
 Seepage through peat soil
 Climatological data
 Water control by pumping
 Water table studies
 Summary














Group Title: Bulletin - University of Florida Agricultural Experiment Station ; 378
Title: Water control in the peat and muck soils of the Florida Everglades
CITATION THUMBNAILS PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00027664/00001
 Material Information
Title: Water control in the peat and muck soils of the Florida Everglades
Series Title: Bulletin - University of Florida Agricultural Experiment Station ; 378
Physical Description: Book
Language: English
Creator: Clayton, B. S.
Neller, J. R.
Allison, R. V.
Publisher: University of Florida Agricultural Experiment Station
Publication Date: 1942
 Record Information
Bibliographic ID: UF00027664
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.

Table of Contents
    Front Cover
        Page 1
    Credits
        Page 2
    Table of Contents
        Page 3
    Foreword
        Page 4
    The Everglades problem
        Page 5
        Page 6
        Page 7
    Description of the Everglades area
        Page 8
        Page 9
    Soils of the Everglades
        Page 10
        Page 11
        Page 12
        Page 13
        Page 14
    Subsidence of peat soils
        Page 15
        Page 16
    Seepage through peat soil
        Page 17
        Page 18
        Page 19
    Climatological data
        Page 20
        Page 21
        Page 22
        Page 23
        Page 24
        Page 25
        Page 26
        Page 27
        Page 28
        Page 29
        Page 30
        Page 31
        Page 32
        Page 33
        Page 34
        Page 35
        Page 36
        Page 37
    Water control by pumping
        Page 38
        Page 39
        Page 40
        Page 41
        Page 42
        Page 43
        Page 44
        Page 45
        Page 46
        Page 47
        Page 48
        Page 49
        Page 50
        Page 51
        Page 52
        Page 53
        Page 54
        Page 55
        Page 56
        Page 57
        Page 58
        Page 59
        Page 60
        Page 61
    Water table studies
        Page 62
        Page 63
        Page 64
        Page 65
        Page 66
        Page 67
        Page 68
        Page 69
        Page 70
    Summary
        Page 71
        Page 72
        Page 73
        Page 74
Full Text


November, 1942


UNIVERSITY OF FLORIDA
AGRICULTURAL EXPERIMENT STATION
WILMON NEWELL, Director
GAINESVILLE, FLORIDA

Cooperating with
UNITED STATES DEPARTMENT OF AGRICULTURE
SOIL CONSERVATION SERVICE
H. H. BENNETT, Chief






WATER CONTROL IN THE

PEAT AND MUCK SOILS

OF THE FLORIDA EVERGLADES


By


B. S. CLAYTON, J. R. NELLER and R. V. ALLISON


Single copies free to Florida residents upon request to
AGRICULTURAL EXPERIMENT STATION
GAINESVILLE, FLORIDA


Bulletin 378






EXECUTIVE STAFF
John J. Tigert, M.A., LL.D., President of the
University'
Wilmon Newell, D.Sc., Directors
Harold Mowry, M.S.A., Asso. Director
L. O. Gratz, Ph.D., Asst. Dir., Research
W. M. Fifield. M.S., Asst. Dir., Admin.4
J. Francis Cooper, M.S.A., Editor'
Clyde Beale, A.B.J., Assistant Editor3
Jefferson Thomas, Assistant Editor3
Ida Keeling Cresap, Librarian
Ruby Newhall, Administrative Manager3
K. H. Graham, Business Manager3
Claranelle Alderman, Accountant3

MAIN STATION, GAINESVILLE
AGRONOMY
W. E. Stokes, M.S., Agronomist'
W. A. Leukel, Ph.D., Agronomist'
Fred H. Hull, Ph.D., Agronomist
G. E. Ritchey, M.S., Associate'
W. A. Carver, Ph.D., Associate
Roy E. Blaser, M.S., Associate
G. B. Killinger, Ph.D., Associate
Fred A. Clark, B.S.A., Assistant
ANIMAL INDUSTRY
A. L. Shealy, D.V.M., An. Industrialist1 a
R. B. Becker, Ph.D., Dairy Husbandmans
E. L. Fouts, Ph.D., Dairy Technologists
D. A. Sanders, D.V.M., Veterinarian
M. W. Emmel, D.V.M., Veterinarian3
L. Swanson, D.V.M., Parasitologist4
N. R. Mehrhof, M.Agr., Poultry Husb.3
T. R. Freeman, Ph.D., Asso. in Dairy Mfg.
R. S. Glasscock, Ph.D., Asso. An. Hush.
D. J. Smith, B.S.A., Asst. An Husb.
P. T. Dix Arnold, M.S.A., Asst. Dairy Husb.3
G, K. Davis, Ph.D., Tech. in An. Nutrition
L. E. Mull, M.S., Asst. in Dairy Tech.'
0. K. Moore, M.S., Asst. Poultry Hush.
C. B. Reeves, B.S., Asst. Dairy Tech.
J. E. Pace, B.S., Asst. An. Husb.
ECONOMICS, AGRICULTURAL
C. V. Noble, Ph.D., Agr. Economist1 '
Zach Savage, M.S.A., Associate
A. H. Spurlock, M.S.A., Associate
Max E. Brunk, M.S., Assistant
ECONOMICS, HOME
Ouida D. Abbott, Ph.D., Home Econ.'
Ruth 0. Townsend, R.N., Assistant
R. B. French, Ph.D., Asso. Chemist
ENTOMOLOGY
J. R. Watson, A.M., Entomologiste
A. N. Tissot, Ph.D., Associate
H. E. Bratley, M.S.A., Assistant
HORTICULTURE
G. H. Blackmon, M.S.A., Horticulturist1
A. L. Stahl, Ph.D., Associate
F. S. Jamison, Ph.D., Truck Hort.
R. J. Wilmot, M.S.A., Asst. Hort.
R. D. Dickey, M.S.A., Asst. Hort.
J. Carlton Cain, B.S.A., Asst. Hort.'
Victor F. Nettles, M.S.A., Asst. Hort.'
Byron E. Janes, Ph.D., Asst. Hort.
F. S. Lagassee, Ph.D., Asso. Hort.2
H. M. Sell, Ph.D., Asso. Hort.'
PLANT PATHOLOGY
W. B. Tisdale, Ph.D., Plant Pathologist' a
George F. Weber, Ph.D.. Plant Path.3
Phares Decker, Ph.D., Asso. Plant Pathologist
Erdman West, M.S.. Mycologist
Lillian E. Arnold, M.S., Asst. Botanist
SOILS
R. V. Allison, Ph.D., Chemist1
Gaylord M. Volk, M.S., Chemist
F. B. Smith, Ph.D., Microbiologists
C. E. Bell, Ph.D., Associate Chemist
J. Russell Henderson, M.S.A., Associates
L. H. Rogers, Ph.D., Asso. Biochemist'
Richard A. Carrigan, B.S., Asso. Chemist4
L. E. Ensminger, Ph.D., Asso. Soils Chem.
H. W. Winsor, B.S.A., Assistant Chemist
Geo. D. Thornton, M.S., Asst. Chemist
R. E. Caldwell, M.S.A., Soil Surveyor
Olaf C. Olson, B.S.. Soil Surveyor


BOARD OF CONTROL
H. P. Adair, Chairman, Jacksonville
R. H. Gore. Fort Lauderdale
N. B. Jordan, Quincy
T. T. Scott, Live Oak
Thos. W. Bryant, Lakeland
J. T. Diamond Secretary, Tallahassee

BRANCH STATIONS
NORTH FLORIDA STATION, QUINCY
J. D. Warner, M.S., Agronomist in Charge
R. R. Kincaid, Ph.D., Asso. Plant Pathologist
R. W. Wallace, B.S., Asso. Agronomist
J. H. Wallance, M.A., Asso. Agronomist
Elliott WhiLehurst, B.S.A., Asst. An. Husb.'
W. C. McCormick, B.S.A., Asst. An. Husb.
Jesse Reeves, Asst. Agron., Tobacco
W. H. Chapman, M.S., Asst. Agron.4
CITRUS STATION, LAKE ALFRED
A. F. Camp, Ph.D., Horticulturist in Charge
V. C. Jamison, Ph.D., Soils Chemist
B. R. Fudge, Ph.D., Associate Chemist
W. L. Thompson, B.S., Associate Ento.
F. F. Cowart, Ph.D., Asso. Horticulturist
W. W. Lawless, B.S., Asst. Horticulturist*
R. K. Voorhees, Ph.D., Asso. Plant Path.
H. O. Sterling, B.S., Asst. Hort.
T. W. Young, Ph.D., Asso. Hort., Coastal
C. R. Stearns, Jr., B.S.A., Chemist
EVERGLADES STA.. BELLE GLADE
J. R. Neller, Ph.D., Biochemist in Charge
J. W. Wilson, Sc.D., Entomologist
F. D. Stevens, B.S., Sugarcane Agron.
Thomas Bregger, Ph.D., Sugarcane
Physiologist
G. R. Townsend, Ph.D., Plant Pathologist
R. W. Kidder, M.S., Asst. An. Hush.
W. T. Forsee, Ph.D., Asso. Chemist
B. S. Clayton, B.S.C.E., Drainage Eng.2
F. S. Andrews, Ph.D., Asso. Truck Hort.'
Roy A. Bair, Ph.D., Asst. Agron.
E. C. Minnurm, B.S. Asst. Truck Hort.
SUB-TROPICAL STA., HOMESTEAD
Geo. D. Ruehle, Ph.D., Plant Path. in Charge
S. J. Lynch, B.S.A., Asst. Horticulturist
E. M. Andersen, Ph.D., Asst. Hort.
W. CENT. FLA. STA., BROOKSVILLE
W. F. Ward, M.S., Asst. An. Hush. in Charge2
RANGE CATTLE STA., ONA
W. G. Kirk, Ph.D., An. Hush. in Charge
E. M. Hodges, Ph.D., Asso. Agron., Wauchula
Gilbert A. Tucker, B.S.A., Asst. An. Husb.4
Floyd Eubanks, B.S.A., Asst. An. Hush.
FIELD STATIONS
Leesburg
M. N. Walker, Ph.D., Plant Path. in Charge4
K. W. Loucks, M.S., Asst. Plant Path.
E. E. Hartwig Ph.D., Asst. Agron. & Path.
Plant City
A. N. Brooks, Ph.D., Plant Pathologist
Hastings
A. H. Eddins, Ph.D., Plant Pathologist
E. N. McCubbin, Ph.D., Asso. Truck Hort.
Monticello
S. 0. Hill, B.S., Entomologist2 4
A. M. Phillips, B.S., Asst. Entomologist2
Bradenton
Jos. R. Beckenbach, Ph.D., Truck Hart. in
Charge
E. G. Kelsheimer, Ph.D., Entomologist
F. T. McLean, Ph.D.. Horticulturist
A. L. Harrison, Ph.D., Asso. Plant Path.
David G. Kelbert. Asst. Plant Pathologist
Sanford
R. W. Ruprecht, Ph.D., Chemist in Charge,
Celery Investigations
Jack Russell, M.S., Asst. Entomologist
Lakeland
E. S. Ellison, Meteorologist' "
Harry Armstrong, Asso. Meteorologist2

1 Head of Department.
2 In cooperation with U. S.
3 Cooperative, other divisions. U. of F.
SOn leave.
















CONTENTS


THE EVERGLADES PROBLEM ..................................

DESCRIPTION OF THE EVERGLADES AREA ..

SOILS OF THE EVERGLADES .........

SUBSIDENCE OF PEAT SOILS .............

SEEPAGE THROUGH PEAT SOILS ................

CLIMATOLOGICAL DATA .................. .......

R ainfall ............ ....................

Evaporation and Transpiration ......

Tem perature ............................... .......

WATER CONTROL BY PUMPING ............ ...

Description of Pumping Plants ......

Fixed and Operating Costs of Pumping

Efficiency Tests on Pumping Plants .......

Farm Ditches ......... ............

M ole Drainage ... ...... ...........

WATER TABLE STUDIES .........

The W ell Lines ... .........

W ater Table Plots .. ....... .............

SUM M ARY .......................... .......... ..

S oils .............. .............. ... .....

Subsidence ............ ....................

S eepage ................... .... .. ...........

Rainfall, Evaporation and Temperature

Water Control by Pumping.- .......

Ditches and Sub-Drainage .......... .

Water Table Studies ........ ..


PAGE
.. .. ... 5

..... .. ... --...... 8

.. - 1 0

..................... 15

---- 17

.......... ..... 20

.. ................ 20

...... ..... ..... 27

S............. ... 35

S...... ............. 38

..... ... .. ...... 3 9

.................. 47

.... ..... ....... 56

.......-.....-.... 60

.. ....... .. 60

... 62

62

.. 70

71
....... ............ 71

.-..-. ..... ...... 71

................... 72

.. ...... 72

.... ... 72

..... 73

.... .. 73






FOREWORD
The reclamation and agricultural utilization of the organic
soils of the Everglades has created a problem of soil conservation
that is vital to the future of this area.
The conservation of organic soils under cultivation is no less
difficult than it is important. Neither is it unique to the soils
of the Everglades, since the record of reclamation activities on
soils of this type in other states and in other countries of the
world shows a practically complete disintegration and destruc-
tion of the soil body, almost without exception, under conditions
of continued use-and abuse.
Everglades soils require protection against natural oxidation
as well as actual burning, and the consequent surface subsidence
which occurs under almost any condition of reclamation.
We must try to learn all there is to be known about the hand-
ling of the natural waters of this tremendous flatland area that
we may use them in such a way as to protect and conserve the
soils under reclaimed as well as unreclaimed conditions, just as
fully as possible. Such an objective is neither drainage nor ir-
rigation, but WATER CONTROL in the fullest sense of the word.
The program towards which such an ideal approach points
must be broad enough to include the hydrology of the entire
Everglades system, that is, the Kissimmee watershed and re-
lated watersheds, Lake Okeechobee, and the original overflow
area which is the Everglades itself. Such a plan also must take
cognizance of the eccentricities of the climate from year to year.
Also it must give most careful consideration to the development
of adequate water reserves to meet not only ever-increasing de-
mands for domestic water supplies, municipal and other, and
the growing requirements of agriculture as the reclaimed area
steadily expands, but also the equally specific needs for soil con-
servation under unreclaimed conditions. Fortunately the several
requirements of the plan do not conflict but can be developed in
full harmnoy with each other, provided the question of water
supply is held paramount and there is no serious shortage at
any time.
In attacking a problem of this breadth we are, of course, ex-
ceedingly grateful for the interest and support of such an or-
ganization as the Soil Conservation Service of the U. S. Depart-
ment of Agriculture. The Chief of this Service, Dr. H. H. Ben-
nett, has had a deep technical interest in the problems of the
Everglades for a great many years, as has also Mr. L. A. Jones,
Chief of the Drainage Division in the Research Branch of the
Service with whose office the cooperation in this phase of the
work has been maintained. The results reported in this bulletin
relate very closely, of course, to the operation and demonstration
project initiated by the Service in 1939 with headquarters in
Ft. Lauderdale. This part of the Service's program in the Ever-
glades is under the management of Mr. C. Kay Davis, to whom
we are also very much indebted for the steady interest and co-
operation of his whole staff during the past three years.
HAROLD MOWRY








WATER CONTROL IN THE PEAT AND MUCK SOILS
OF THE FLORIDA EVERGLADES
By B. S. CLAYTON,' J. R. NELLER and R. V. ALLISON

In the spring of 1932 a cooperative agreement was entered
into by the Agricultural Experiment Station of the University
of Florida and the Bureau of Agricultural Engineering of the
United States Department of Agriculture for the purpose of
investigating problems relating to water control in Florida2 peat
soils. Headquarters for the work was established at the Ever-
glades Experiment Station near Belle Glade. The work has
continued since that time.
Early efforts at water control were confined to a system of
gravity ditches. Due to soil subsidence and the flat topography
of the land this method proved inadequate and pumps, installed
later, now serve nearly all the cultivated land.
All elevations used in this report are based on the old Punta
Rassa datum which has been generally used by drainage dis-
tricts in the northern Everglades. This datum is approximately
1.4 feet below the mean sea level datum of the United States
Coast and Geodetic Survey. Hence to reduce the elevations used
to mean sea level 1.4 feet should be subtracted from the figures
given.
Figure 1 is a map of the northern Everglades showing some
of the larger drainage canals and pumping plants.

THE EVERGLADES PROBLEM
The outstanding problem of the Florida Everglades is con-
cerned with prolonging the useful life of the cultivated land and
conserving the virgin lands from the destructive effects of sub-
sidence and fires. A successful solution of this problem would
benefit the cities of the lower East Coast, since these depend
largely on shallow wells for their water supply. Insofar as a
higher water table can be maintained in the Glades a larger yield
of salt-free water can be obtained from these wells. It is also
believed that a higher water table would reduce the frost hazards
in the cultivated lands.
Associate drainage engineer, Soil Conservation Service, U. S. Depart-
ment of Agriculture, and drainage engineer, Everglades Experiment Station.
SFollowing a reorganization of the Department, effective July 1, 1939,
the cooperation has been continued between the Soil Conservation Service
and the Experiment Station.






Florida Agricultural Experiment Station


LAKE OKEECHOBEE Q R
Canal Point

Moore Haven
Pahokee M
_UC





Lake Harbor


Pumping p s









and well lines in the Okeechobee area.

A complete solution of this problem would require a return
of the Everglades to their original condition, which is now im-
practicable. However, if the available water is so distributed
that a higher water table is maintained the losses from subsi-
dence and fires can be much reduced.

The useful life of the cultivated lands can be increased by
maintaining the highest water table compatible with good crop
yields. A water table depth of 1.5 to 2.0 feet produces the best
yield for most crops now grown in the Everglades.

The water table in the virgin lands can be held somewhat
higher by retarding the rate of run-off. The large diagonal
canals have increased this rate of run-off and their continuous
flow bleeds the Glades of much seepage water which if retained
would result in a higher water table. The land on either side
of the North New River Canal is about two feet lower than that
several miles back, also the water table, during dry weather, is
much lower near the canal than several miles out. As far as
possible the free flow of these canals should be restricted by
possible the free flow of these canals should be restricted by





Water Control in the Soils of the Everglades


dams which should remain closed at all times except during
extreme high water.
If these canals were held at near bank full stage the total
amount of pumping would be increased due to seepage into the
diked areas, but as pumping costs are low this increase would
not greatly change the cost of operation of pumping districts.
A system of dikes has been proposed as a means of holding
rainfall on the idle lands. There is some doubt as to whether
the increased height of the water table during the spring months
would be sufficient to justify the costs. Also, it would be diffi-
cult to protect these dikes from fires. However, the possibility
of retaining water by dikes should be examined. Several typi-
cal areas should be completely enclosed and the results observed
before expanding the system.
The discharge from Lake Okeechobee through its two outlets
averages about 11 million acre-feet per year, but due to the
elevation of the land outside the levee it would be very difficult
to spread this water over the virgin lands. However, some of
this water could be used to maintain a high level in the large
canals during the dry season, and thus decrease the subsidence
losses.
Under present conditions the cultivated acreage in the Glades
is being expanded without any general plan. This is leading to
a condition where much of the land back from the existing roads
will have no outlet. Under this condition it is impossible to
design outlet canals with any certainty as to the drainage areas
which they should serve. This unfortunate situation will be-
come worse unless some general plan of development is adopted.
After a field survey is completed of the agricultural land a
map should be prepared and a system of levees and canals pro-
jected which would provide outlets for all agricultural land.
These levees and canals could be constructed as need arises for
new land, but would conform with the general plan adopted. All
new land should then come in as sub-districts with pumps placed
so as to discharge at points provided in the general plan.
It might prove feasible to provide north and south outlet
ditches along range lines and require sub-districts to extend back
three miles. Those interested in forming a new sub-district
should first prepare a plan and submit this to some designated
authority for approval before work is begun. Only in this
manner can a consistent plan of development be achieved.
A study of the field data might show that these outlet canals





Florida Agricultural Experiment Station


along the range lines could discharge directly into the open
Glades without an excessive increase in the lift of the sub-district
pumps. If such a plan proved feasible the pumped water would
move very slowly over the virgin lands and increase the height
of water table in these areas. Also it would not be necessary
to construct drainage works much in advance of development.
Some plan of development is urgently needed and when the
survey is completed a study should be made with this end in
view.
DESCRIPTION OF THE EVERGLADES AREA
The Everglades area includes Lake Okeechobee with its tribu-
tary drainage area; the peat lands known as the Everglades,
and the sand ridges on either side.
Lake Okeechobee covers an area of approximately 730 square
miles. Its shape, is roughly that of a circle with a diameter of
30 miles. The lake occupies a shallow depression the lowest part
of which is approximately at sea level. The total tributary area,
including the lake surface, is about 5,200 square miles. Of this
total the Kissimmee valley accounts for 3,079 square miles. Prior
to the construction of drainage works, the lake overflowed into
the Glades when the stage reached an elevation of about 21 feet.
Before the opening of the St. Lucie Canal in 1926 the recorded
stages varied from 13.8 to 21.7 feet. Since that time the range
has been from 11.8 to 19.5 feet and the average stage has been
approximately 16.0 feet.
The lake is now regulated through two outlets. The St. Lucie
Canal to the Atlantic Ocean has a capacity of 5,000 second feet
at a 17-foot lake stage, and the Caloosahatchee Canal to the Gulf
has a capacity of 2,500 second feet. The combined capacity of
the two outlets is sufficient to lower the lake about one foot
from normal level in 30 days. The lake is now regulated by the
United States War Department and the stages are held as nearly
as possible between 14 and 17 feet.
A levee has' been built along the east and south sides of the
lake, extending from the St. Lucie Canal to Fish-eating Creek,
a distance of about 50 miles. An additional 15 miles of levee
also has been built at the north end of the lake near Okeechobee.
The elevation of the levee top varies from 34 to 36 feet. This
levee will be a protection against huge waves caused by hurri-
canes.
The Florida Everglades contains about three-fourths of the





Water Control in the Soils of the Everglades


peat lands of the state and is probably the largest continuous
body of peat in the world. It is primarily a great sawgrass
marsh covering about 4,000 square miles. It lies in a trough
about 40 miles wide by 100 miles in length that extends from
Lake Okeechobee almost to the end of the peninsula and is
bounded on either side by a low sandy ridge. The slope from
north to south is about two inches per mile. The elevation near
Lake Okeechobee is now about 16 feet above mean low tide.
Prior to drainage, this great peat area was wet during a large
portion of the year. The overflow from Lake Okeechobee to-
gether with the normal rainfall of about 54 inches per year and
some run-off from the higher lands on either side resulted in a
high water table which conserved the soil and permitted a slow
increase in depth of peat from year to year.
The depth of peat varies generally from north to south. Near
the east side of Lake Okeechobee it is 8 to 12 feet deep but in
the southern portion of the Glades it is quite shallow. The depth
over a large part of the area is now less than three feet, and
probably not more than 500,000 acres has a depth of more than
five to six feet.
Approximately 85,000 acres of the peat and muck lands of
the northern Everglades are now in agricultural use. About
one fourth of this is in sugarcane and most of the remainder is
used for truck crops. Nearly all the cultivated acreage is served

Fig. 2.-Limerock under peat along the North New River Canal near
South Bay.





Florida Agricultural Experiment Station


by pumps. In addition to this there are about 20,000 acres in
cultivation near the southeastern edge of the Everglades and
approximately one fourth of this acreage is in citrus groves. The
peat depth in this part of the Everglades is very shallow and
only a small portion of the land is served by pumps.
A considerable portion of the Everglades area is underlaid
with a more or less porous deposit of limestone and marl con-
taining marine shells. This is known as the Fort Thompson
formation. It underlies the area adjacent to Lake Okeechobee
and extends south to about Twenty Mile Bend on the North New
River Canal. West of the Palm Beach County line a layer of sand
is usually found between the peat and the rock. Most of the re-
maining portion of the area is underlaid with Miami oolite. This
is a white limestsone which is considerably more porous than
the Fort Thompson formation.
The underlying rock formation along the North New River
Canal near South Bay is shown in Figure 2. This picture was
taken when the water had been pumped from a section of the
canal in order to excavate rock for a new road.

SOILS OF THE EVERGLADES
The soils of the Everglades usually have been divided into
three general types called "custard apple," "willow and elder,"
and "sawgrass." According to a recent classification and survey
these three general types are to be known as Okeechobee muck,
Okeelanta peaty muck, and Everglades peat, respectively. There
are some finer distinctions and a few other types, but this general
classification will be adhered to in this report.
By far the greater portion of the peat soils of the Everglades
is composed of the partially decomposed remains of sawgrass.
The marshy condition of the Glades, during the period of forma-
tion, prevented a more complete decomposition of this material.
In its original condition the sawgrass peat is a brown fibrous
mass in which the partially decayed sawgrass roots can be readily
distinguished. These roots are approximately in a vertical posi-
tion. After drainage, cultivation and weathering gradually
transform the top soil into a condition approaching a true muck.
The structure then changes into an amorphous mass, the density
increases, the color becomes dark, and the rate of seepage
through the soil is retarded.
When saturated the soil is a little heavier than water. After






Water Control in the Soils of the Everglades


drainage, the water retained by the soil is equivalent to about
three-fourths the weight of the field sample. The oven-dry
weight of the soil below the normal water table is about eight
pounds per cubic foot of field sample, and the ash or mineral
content is about 10 percent of the dry weight. The oven-dry
weights of the upper 18 inches of soil, from fields in cultivation
for 10 to 15 years, indicate that the density about doubles after
a considerable period of intensive use.
In December, 1935, soil samples were taken from 16 locations
within a 10-acre field at the Everglades Experiment Station. The
figure for each six inches of depth, as shown in Table 1, is an
average of 16 samples taken with a brass cylinder six inches long
and four inches in diameter. The field has been drained for the
past 20 years but had been in cultivation only two years before
the samples were taken. At a depth of 13 to 18 inches is a thin
layer of slightly plastic, peaty muck, but the remainder of the
soil is typical sawgrass peat.

TABLE 1.-OVEN-DRY WEIGHT AND ASH WEIGHT OF SOILS AT
EVERGLADES EXPERIMENT STATION.
Depth of Oven-Dry Weight Ash Weight Ash to Oven-
Sample per Cu. Foot per Cu. Foot Dry Weight
Inches Pounds Pounds Percent
0-6 17.5 1.76 10.1
7-12 12.2 1.27 10.4
13-18 11.4 2.00 17.5
19-24 9.5 1.14 12.0
25-30 8.1 0.68 8.4
31-36 7.5 0.62 8.3
37-42 7.8 0.70 9.0
43-48 7.7 0.73 9.5

Average 10.2 1.11 10.6

The large ash weight for the 13 to 18 inch depth is due to
the thin layer of peaty muck. If the samples for this depth are
omitted the remaining samples of sawgrass peat show an average
ash weight of approximately 10 percent of the oven-dry weight.
The greater dry weight of the upper portion of the soil shows
the effect of compaction, weathering and oxidation as the saw-
grass peat is slowly changed into a condition approaching a true
muck. It is probable that the water table in this field has aver-
aged about 24 inches and has seldom been lower than 30 inches.
The samples below the normal water table show little difference
in dry weights.







Florida Agricultural Experiment Station


TABLE 2.-SOIL SAMPLES ON SUBSIDENCE LINES-APRIL, 1938.
Results Based on One Cubic Foot of Field Samp-e.
Moist Oven-Dry Ash Water in Ash in Oven
Depth We'ght Weight Weight Moist Soil Dry Soil
Inches Pounds Pounds Pounds Percent Percent
Line A
1-6 37.4 9.4 1.41 75 15.0
7-12 43.7 6.9 0.69 84 10.0
13-18 54.9 9.6 1.26 83 13.1
19-24 63.3 12.3 2.08 81 16.9
25-30 60.7 9.8 1.35 84 13.8
31-36 59.7 i 8.1 0.94 86 11.6
37-42 63.4 7.8 0.90 88 11.6
43-48 65.2 8.6 0.95 87 11.0
Line H
1-6 59.8 23.0 2.78 62 12.1
7-12 64.6 14.4 1.90 78 13.2
13-18 62.9 10.9 1.37 83 12.6
19-24 64.1 12.4 2.53 81 20.4
25-30 62.2 8.8 0.86 86 9.8
31-36 64.1 7.6 0.79 88 10.4
Lawn
1-6 57.2 14.8 2.46 74 16.6
7-12 61.8 12.6 1.75 80 13.9
13-18 62.9 10.3 1.35 84 13.1
19-24 64.6 12.9 2.54 80 19.7
25-30 62.5 8.6 0.76 86 8.8
31-36 63.1 7.4 0.72 88 9.7

Remarks
Line "A" in Sec. 10 at Everglades Experiment Station. Virgin sawgrass
soil. Water table approximately 3.5'.
Line "H" at Everglades Experiment Station near Well 12. Sawgrass soil
in cultivation since 1924.
Line over grass lawn at Everglades Experiment Station. Sawgrass soil.

Table 2 shows three sets of soil samples taken from lands at
the Everglades Experiment Station in April, 1938. The high
ash content of the 19 to 24 inch sample in each set is due to the
thin layer of peaty muck referred to above. Line A is on virgin
sawgrass soil, south of the Experiment Station. Line H is on
land which has been in truck crops for about 14 years and the
"Lawn" line is on soil which has been covered with St. Lucie
grass for nearly the same period.
The Okeechobee (custard apple) or plastic muck of the Ever-
glades covers about 30,000 acres located along the east and south
sides of Lake Okeechobee. It is thought to have been formed
from the residue of succulent water plants deposited during a
period when the area was continuously under water. The ash
or mineral content varies from approximately 35 to 70 percent
of the oven-dry weight. This soil is dark in color and homo-






Water Control in the Soils of the Everglades


generous in structure. It was commonly called "custard apple"
muck on account of the custard apple trees which originally
covered it. The proximity of this soil to the lake probably
accounts to some extent for the high mineral content. In its
original state this soil was less fibrous and contained more of
the elements essential to plant growth than did the sawgrass
peat. Hence it was the first of the Everglades lands to be used
since it was also somewhat higher and therefore had better
natural drainage.

TABLE 3.-SOIL SAMPLES ON SUBSIDENCE LINES-APRIL, 1938.
Results Based on One Cubic Foot of Field Samp:e.


Moist Oven-Dry
Depth We'ght Weight
Inches Pounds Pounds

Line S
1-6 54.2 18.4
7-12 55.3 17.7
13-18 63.8 17.0
19-24 66.0 18.0
25-30 65.3 13.2
30-36 63.1 9.6

Line O
1-6 47.2 27.5
7-12 40.6 15.3
13-18 47.6 14.3
19-24 55.6 18.0
25-30 62.0 24.3
31-36 69.4 24.6

Line E
1-6 52.2 31.7
7-12 60.9 28.2
13-18 55.5 23.6
19-24 59.4 23.4
25-30 61.8 19.3
31-36 60.8 13.6
37-42 70.8 11.1
43-48 63.1 9.1

Line D
1-6 58.4 41.7
7-12 53.6 24.1
13-18 54.2 20.8
19-24 56.1 18.7
25-30 64.1 15.6
31-36 69.8 16.0
37-42 70.4 18.4
43-48 72.8 18.0


Ash
Weight
Pounds


5.46
4.11
7.80
8.19
3.54
1.34

14.85
7.19
7.12
11.35
18.30
15.15


15.88
19.38
17.04
16.31
10.81
2.82
1.55
0.96


26.52
15.91
13.40
12.29
7.80
10.53
10.30
12.22


Water in
Moist Soil
Percent

66
68
73
73
80
85


42
62
70
68
61
65


39
54
58
61
69
78
82
86

29
55
62
67
76
77
74
75


Ash in Oven
Dry Soil
Percent

29.7
23.2
45.9
45.5
26.8
14.0


54.0
47.0
49.8
63.1
75.3
61.6


50.1
68.8
72.2
69.7
56.0
20.7
14.0
10.5

63.6
66.0
64.4
65.7
50.0
65.8
56.0
67.9


Remarks
Line S near Well 18 at Canal Point. Willow and elder soil.
Line 0 near Well 7 at Canal Point. Okeechobee muck.
Line E at Well 10 on Boe farm near Pahokee. Okeechobee muck.
Line D at Well 8 near Bean City. Okeechobee muck.


i


~






Florida Agricultural Experiment Station


The samples from Lines O, E and D as shown in Table 3 are
typical Okeechobee (custard apple) muck. The low ash content
of the bottom 18 inches of soil on Line E is due to a layer of
sawgrass peat. At a depth of 25 to 30 inches on Line 0, and 13
to 18 inches on Line E, a two or three inch layer of yellow and
grayish material was encountered. Tests showed this to be ash;
hence the high mineral content of the samples at the above
depths. Such ash deposits found in this location and elsewhere
in the Everglades indicate that destructive fires occurred in this
area in the distant past.
Between the Okeechobee muck and the Everglades peat is an
intermediate soil type, Okeelanta peaty muck, commonly called
"willow and elder" land. This is somewhat similar to the saw-
grass peat but has a higher ash content and usually a thin,
well defined layer of plastic muck within the top two feet of the
profile. The zone of Okeelanta peaty muck is not clearly defined
but probably covers about 40,000 acres. Line S, shown in Table
3, is on soil of this type.
In addition to the three types of soil previously mentioned
there is a substantial area of Loxahatchee and Gandy peats. The
former type was formed from a mixture of sawgrass residue and
other vegetation, including water grasses and lilies, and largely
comprises the so-called "slough areas." These areas are usually
quite wet and are probably best suited for wild life reserves.
There is a large body of this land along the east side of the Glades
















Fig. 3.-Shrinkage of organic soils. Center cylinder shows original size.
Sample on left is Everglades peat; sample on right is Okeechobee (custard
apple) muck.






Water Control in the Soils of the Everglades


between the Hillsboro and West Palm Beach canals. The latter
type is composed of woody material derived from various species
of bay and myrtle, and occupies the small islands and ridges
commonly associated with the sloughs that are made up of the
Loxahatchee type.
Peat soils are subject to much shrinkage when dried and will
not expand to original volume when water is again added.
Figure 3 shows two soil samples which were oven-dried. The
center cylinder shows the original size of the samples. The one
on the right is Okeechobee (custard apple) muck; the one on
the left is Everglades peat.

SUBSIDENCE OF PEAT SOILS

As the subject of subsidence in the Everglades has been cov-
ered in special reports,3 only a summary will be given here.
Peat soils are formed by the slow accumulation of plant resi-
dues under very wet conditions.4 The complete decomposition
of the plant material is prevented by the high water table usually
found in swampy areas. After the natural water table is lowered
by drainage the ground surface elevation begins to fall. This
subsidence is due to loss of water and to slow oxidation; also
to compaction of the top layer by cultivation.
After a virgin area is drained the subsidence is very rapid at
first, but decreases with time. Figure 4 shows the rate of sub-
sidence along a reference line near Okeelanta, Florida. A small
portion of the loss shown is due to fires, but by far the greater
portion is due to subsidence resulting from drainage.
Most of the cultivated lands of the northern Everglades have
subsided approximately five feet since drainage was begun about
25 years ago. The rate of subsidence of sawgrass soil, in recent
years, has averaged about one inch per year. Okeechobee (cus-
tard apple) muck subsides at a somewhat slower rate. A large
number of reference lines have been established in the northern
Everglades for a continued study of this subject.
The data so far available indicate that the rate of subsidence
is approximately proportional to the average depth of water

3 Clayton, B. S. Subsidence of peat soils in Florida. Bureau of Agri-
cultural Engineering. U.S.D.A. Report No. 1070, 1936. (Mimeog.)
*Allison, R. V., O. C. Bryan, and J. H. Hunter. The Stimulation of
plant response on the raw peat soils of the Florida Everglades through the
use of copper sulphate and other chemicals. Florida Agr. Exp. Sta. Bul.
190:33-80. 1927.






Florida Agricultural Experiment Station


Aug. 914, Elv. 20.3

P.... t' /

i9 i -
t'l. As2, thpe lo19iB, goe th wtrab e a re~te





e I c eb.l e o933,1, on5,50
iI 9' [ 6 j i






Fig. 4.-Surface subsidence of Okeelanta peaty muck near the Bolles Canal.

table.5 As the lowering of te water table exposes a greater
volume of soil to slow oxidation a greater subsidence loss nat-
urally occurs.
Total subsidence following drainage does not appear to have
been much affected by the type of crop grown, as lands planted
to cane, truck crops, or grasses have subsided approximately the
same total amount. Even virgin lands exposed to pump drainage
or near the large gravity canals have subsided about four feet.
A large number of soil samples have been taken from various
reference lines. These have been oven-dried and the density and
ash content determined. The results indicate that the top 18
inches of soil on fields used intensively for truck crops has
doubled in density in about 10 years of use. The soil densities,
based on oven-dry weights, decrease from the top downward.
In virgin soil areas which have subsided almost as much as the
cultivated fields, the density of the top soil shows very little
increase over that below the permanent water table. For equal
subsidence a greater loss of soil mass has occurred in the drained
but idle lands. It, therefore, appears evident that the land should
be placed in cultivation as soon as possible following drainage
in order to conserve the soil.
Roe, H. B. A study of influence of depth of ground water level on
yields of crops grown on peat lands. Minn. Agr. Exp. Sta. Bul. 330: 1-32.
1936.





Water Control in the Soils of the Everglades


Much of the virgin land in the northern Everglades has sub-
sided from three to four feet due to gravity drainage by the large
canals and there has been little or no increase in density in the
upper portion of the soil. Subsidence levels over similar saw-
grass land near Pahokee show that after pump drainage was
established and the area was planted to cane a further subsi-
dence of 1.8 feet occurred during 10 years of use. It is probable
that approximately an equal amount of subsidence will occur
during the next 20 years, making the loss after 30 years of use
about 3.6 feet. It is, therefore, important that before new areas
of virgin lands are brought into use, the depth of soil and prob-
able subsidence should be carefully considered in planning the
drainage works.
From the records available it is estimated that the average
water table in the cultivated lands of the northern Everglades
is approximately 2.5 feet. This may vary from surface to a
depth of four feet, due to the variation in season, rainfall and
the amount of pumping. If the water table were held to an
average depth of 1.5 to 2.0 feet, the subsidence would be propor-
tionally reduced. Aside from maintaining a higher water table,
there appears to be no practical way of decreasing subsidence in
peat soils.
SEEPAGE THROUGH PEAT SOIL
There is considerable evidence that the seepage movement in
the Everglades is largely through the porous rock and sands
beneath the peat. Typical profiles of the water table between
drainage ditches approximate a rather flat curve over the major
portion of the line, but about 100 feet from the ditches the pro-
files show a steep slope, indicating the resistance of the peat
to lateral seepage. In porous material like sand the slope would
be much flatter. It was also noted that the completion of the
new lake levee, with the probably impervious seepage fills be-
neath, apparently had no substantial effect on the ground water
table of the protected lands.
In the spring of 1939 the water in the North New River Canal
was a foot or more below the rock over a long stretch below
Okeelanta. Well readings on the west side of the canal showed
a water table slope towards the canal for a distance of at least
two miles back (Fig. 5). From the canal to a point a half mile
back, the seepage gradient rose approximately two feet. It was
thus evident that the seepage water from the peat lands on
either side reached the canal through the porous rock formation.











L- 2 MeIs -h f B,1- C-I ,
1,0,, pra HehoyNo 26


049.0496,0,,44 9 04.0' ,9 091, '1u 910
A-~rli G,-ud 1 7,Mo~~199. 1' t




121'.






-F2












17t4
1912 -L 194__ 0
1. "~S--- 345 -


Fig. 5.-Profiles showing water table in virgin peat land after a very dry period.





Water Control in the Soils of the Everglades


Figure 5 shows surface profiles and water tables along two
lines. One begins at the North New River Canal two miles below
the Bolles Canal near Okeelanta and the second begins four miles
south of the Bolles Canal. Both lines extend two miles to the
west over sawgrass land. The depths to water table were very
close to maximum, as the rainfall for the preceding year was
one of the lowest recorded.
To make a rough comparison of the rates of seepage through
vertical and horizontal sections of sawgrass peat, three samples
were taken in brass tubes four inches in diameter. One vertical
sample was taken from the top 18 inches of soil, a second from
the 18 to 36-inch depth, and a horizontal sample was taken at
a depth of three feet. The land has been drained by pumps for
14 years but has been in cultivation for only a few years. The
vertical samples were 18 inches long. The horizontal sample
after compression of several inches due to forcing the tube
through the soil was 11 inches long. The tubes were set up so
that the difference in level of the inflowing and outflowing water
was held constant at 19 inches.
The average depth of water passing through the top 18-inch
sample was 0.30 foot per day, that through the 18 to 36-inch
vertical sample was 27.3 feet and that through the horizontal
sample was 0.25 foot per day. The second vertical and the hori-
zontal samples were both in the brown fibrous peat, and the wide
difference of seepage movement through them doubtless is due
to the structure of the partially decayed sawgrass residue which
provides small openings along vertical lines. The seepage
through the top sample of soil was not much greater than that
through the horizontal one. The top soil is changed by weather-
ing and cultivation into a very finely fibrous peat. The density
is increased and the original vertical seepage lines are largely
obliterated. Hence the decrease in rate of seepage movement.
This change is evident in old cultivated fields for, subsequent to
a heavy rain, surface water remains for extended periods after
the ditches are pumped to a low level.
The rates of seepage through the samples were doubtless af-
fected to some extent by compaction. However, the differences
were so great that it seems reasonable to conclude that the seep-
age movement through the soil is much greater in a vertical
than in a horizontal direction.





Florida Agricultural Experiment Station


CLIMATOLOGICAL DATA
RAINFALL
On the peat lands near Lake Okeechobee there are four rain-
fall stations with records of more than 14 years. These are
located at Canal Point, Moore Haven, Everglades Experiment
Station, and the Shawano Plantation. Also, there was a record
at Ritta from 1914 to 1930, inclusive, but this station was dis-
continued in 1930. Ritta was located on the south shore of the
lake about two miles west of the Miami Canal.
The Station at Canal Point is maintained by the Cane Breed-
ing Experiment Station of the U. S. Department of Agriculture;
the one at Moore Haven by the U. S. Weather Bureau; and the
one at Shawano by the Brown Company. Tables 4, 5, 6 and 7
show the monthly and annual rainfall for the four stations.
Maximum, minimum and average monthly and annual rainfalls
also are shown.
The average rainfall for the four-month period from June to
September at the Everglades Experiment Station is 60 percent
of the mean annual precipitation and at the other three stations
it is 59 percent of the annual amount. December is the driest
month at each of these stations, with an average of about one
inch.
Two of the longest rainfall records in South Florida are those
at Fort Myers and Miami. A 70-year record at Fort Myers,
including 1938, shows a mean annual precipitation of 51.84
inches, a maximum of 82.64 inches, and a minimum of 32.85
inches. At Miami a 51-year record shows a mean annual of
59.51, a maximum of 89.07, and a minimum 33.15 inches.
The record shown for the Everglades Experiment Station
covers 14.5 years. The maximum rainfall for a calendar year
was 66.14 and the minimum was 40.99 inches. However, the
maximum rainfall during a consecutive 12-month period was
73.81 and the minimum was 34.98 inches.
Table 8 shows the record of excessive precipitations at the
Everglades Experiment Station for the years 1935 to 1938, as
determined from the charts of a weighing rain gage. Only 15
storms of two inches or more were recorded during these four
years. The greatest rate for one hour was 3.25 and that for
two hours was 3.35 inches. The Weather Bureau record at
Miami for the period 1912 to 1930 shows a maximum of 3.50
in one hour and 6.11 inches in two hours. These Miami records
were obtained from November storms.










TABLE 4.-RAINFALL IN INCHES AT CANAL POINT.


Year Jan. Feb.


1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1935

1937
1938

Av.
Max.
Min.


1.53
3.00
4.46
0.19
0.3:i
0.19
1.34
2.54
2.05
0.26
1.54
0.25
0.16
2.40
4.30
0.12

1.92
6.19
0.12


0.14
2.23
2.24
2.25
1.80
1.38
0.07
3.03
0.91
2.38
0.35
5.36
2.81
5.69
1.81
0.84

2.08
5.69
0.07


Mar.


0.34
3.71
2.46
1.63
2.37
3.48
0.60
4.32
4.27
0.87
4.73
2.77
0.17
3.27
4.88
1.08

2.56
4.88
0.17


A


pr. May


55 7.06
17 2.27
50 9.73
33 1.54
08 1.54
72 3.10
32 5.43
25 6.10
71 3.05
67 3.49
.42 1.31
.64 6.27
.45 0.76
.39 6.10
.36 1.92
.45 3.13

.56 3.93
.25 9.73
.39 0.76


June


6.62
4.84
8.62
8.62
6.31
5.42
11.74
16.96
0.49
11.26
7.62
7.96
6.11
14.29
4.44
6.67

8.00
16.96
0.49


July


8.48
11.08
8.47
7.45
7.32
14.57
11.26
4.08
3.33
4.91
14.02
5.20
3.98
5.44
14.62
7.28

8.22
14.62
3.33


SAug. Sept.


9.95
1.85
7.12
5.72
8.14
14.13
6.31
3.07
4.67
9.91
8.51
8.14
3.62
S8.59
9.37
5.52

7.16
14.13
1.85


8.31
10.97
4.09
14.82
3.31
16.45
10.70
5.36
5.64
2.40
8.16
11.69
11.90
4.08
5.88
8.45

8.26
16.45
2.40


Oct.


3.17
18.14
2.25
1.24
3.35
0.77
3.08
5.14
4.43
4.51
4.36
2.40*
4.44
2.84
6.50
3.69

4.39
18.14
0.77


Nov.


0.43
0.89
1.67
0.72
0.49
1.24
0.69
0.67
0.70
25.09
1.84
0.55*
0.57
5.08
2.23
0.97

2.74
25.09
0.43


Dec.


0.45
0.15
1.99
0.10
0.40
0.20
1.08
2.77
4.62
0.16
0.09
0.58*
1.22
1.65
0.26
0.10

0.99
4.62
0.09


Annual
To al

48.03
61.30 .
56.60 o
53.61
36.44
62.65
54.62
63.29
39.87
67.91
58.95
58.81
41.19
59.82
59.57
38.30

53.81
67.91
36.44
ca
-- G


*Rainf;ll for month estimated from records of nearby stations.










TABLE 5.-RAINFALL IN INCHES AT MOORE HAVEN.


Year Jan. Feb.


1918
1919 1
1920 2
1921 0
1922 0
1923 0
1924 3
1925 2
1926 3
1927 0
1928 C
1929 C
1930 C
1931 2
1932 1
1933 1
1934 1
1935 C
1936
1937
1938 (

Av. ]
Max.
Min.


3.70
2.59
1.99*
1.10
0.49
1.75
1.88
1.19
2.09
2.31
0.14
3.23
0.76
3.13
0.19
2.89
1.00
4.97
1.70
0.57

1.88
4.97
0.14


Mar.



2.83
0.53
0.84*
0.74
0.62
3.38
2.04
1.12
1.70
2.46
0.52
4.76
5.90
2.87
3.88
2.73
0.03
1.95
4.83
0.34

2.20
5.90
0.03


Apr. May June


2.05
0.62
5.13
0.66*
0.46
3.55
3.55
3.92
3.82
2.02
1.52
1.55
4.12
3.44
1.76
6.92
2.22
5.18
2.55
4.89
0.21

2.86
6.92
0.21


0.35
6.70
3.05
5.86*
5.14
11.70
1.21
6.43
2.13
1.94
4.19
2.73
11.33
1.59
6.05
3.89
6.43
3.57
5.41
4.94
6.28

4.81
11.70
0.35


2.55
10.59
6.84
2.16*
9.82
12.52
8.86
8.69
15.05
10.79
8.12
9.35
17.85
1.20
4.96
4.66
4.36
5.84
14.59
3.59
7.40

8.08
17.85
1.20


July Aug. ISept. Oct.


2.87
6.88
15.21
5.11*
7.63
7.54
11.77
4.68
11.24
5.79
5.43
8.44
4.72
2.68
6.25
5.36
8.48
5.09
2.99
13.79
8.20

7.15
15.21
2.68


6.94
4.12
4.51
3.65*
6.72
10.04
4.76
9.83
6.24
8.61
11.82
4.93
11.61
10.34
15.71
5.77
6.20
5.50
5.79
4.71
2.39

7.15
15.71
2.39


10.83 2.72
2.78 0.90
3.18 2.72
2.16* 8.35
14.93 10.70
4.23 1.39
8.41 13.39
1.08 1.54
8.90* 1.93*
6.99 4.12
14.60 0.47
13.45 1.71
11.26 6.33
5.06 1.94
5.99 2.93
2.75 5.18
4.18 5.54
9.53 1.42
11.51 3.55
4.48 8.72
2.23 3.92

7.05 4.26
14.93 13.39
1.08 0.47


*Rainfall for month estimated from records of nearby stations.


0.98
4.86
4.54
2.19
1.56
0.21
0.30
0.93
1.74*
0.38
0.97
1.27
0.45
0.08
3.28
0.92
3.58
1.71
0.58
5.47
1.52

1.79
5.47
0.08


Annual
Total


46.38
51.03
33.67
60.39
52.89
60.52
46.06
56.95
44.93
52.62
46.30
78.48
35.92
54.97
41.45
48.20
40.87
57.30
59.63
33.78

50.12
78.48
33.67


0.73
1.15
0.63
0.25
0.89
0.28
0.09
2.83
0.10
0.39
0.31
1.39
2.33
0.35
0.07
0.28
0.26
1.48
1.18
0.44
0.11

0.74
2.83
0.07













Year Jan.


1924
1925 3.58
1926 5.39
1927 0.32
1928 0.31
1929 1.20
1930 1.92
1931 2.31
1932 1.72
1933 0.64
1934 0.14
1935 0.30
1936 1.91
1937 2.97
1938 0.46

Av. 1.65
Max. 5.39
Min. 0.14


TABLE 6.-RAINFALL IN INCHES AT THE EVERGLADES EXPERIMENT STATION.

Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov.


6.59 3.72 8.49 15.84 0.62
2.49 2.37 3.78 9.38 5.61 5.56 12.36 4.17 0.49 1.14
0.66 1.48 1.81 3.69 9.29 10.57 10.40 13.60 3.58 0.91
2.90 2.18 2.44 3.19 7.08 12.77 11.45 6.41 4.50 0.42
1.66 3.83 1.78 2.61 9.20 8.25 1 1.31 19.04 1.46 1.07
0.49 1.70 2.61 8.92 11.11 7.32 3.79 12.23 4.71 4.13
2.40 6.32 6.03 4.43 19.61 6.28 3.74 3.58 4.94 0.56
1.17 3.93 4.41 3.16 0.59 3.05 7.67 10.68 4.16 0.51
2.13 1.56 1.54 4.69 16.01 3.93 10.59 7.43 3.68 12.36
0.38 5.42 6.90 4.04 9.51 3.85 12.75 11.89 5.30 4.50
1.91 7.10 3.11 5.20 10.15 10.09 12.41 7.44 3.22 0.65
1.32 0.41 5.32 1.08 8.45 6.37 6.54 10.88 5.71 0.36
4.04 2.40 1.96 6.39 18.61 6.09 5.33 5.84 1.65 9.17
1.21 5.87 6.00 3.38 7.74 7.65 7.89 8.35 4.92 2.08
1.14 1.87 0.32 4.52 5.44 8.85 2.65 10.09 2.78 2.66

1.71 3.32 3.43 4.62 9.89 7.15 8.17 9.34 4.46 2.74
4.04 7.10 6.90 9.38 19.61 12.77 12.75 19.04 15.84 12.36
0.38 0.41 0.32 1.08 0.59 3.05 2.65 3.58 0.49 0.36


Dec. Annual
To:al

0.22
2.84 53.77
0.55 61.93
0.42 54.08
0.25 60.77
0.92 59.13
3.54 63.35
1.11 42.75
0.50 66.14
0.12 65.30
0.82 62.24
2.07 48.81
1.18 64.57
0.38 58.44
0.21 40.99

1.01 57.30
3.54 66.14
0.12 40.99














TABLE 7.-RAINFALL IN INCHES ON THE SHAWANO PLANTATION.


July


Jan.



4.86
0.37
0.83
0.46
1.33
2.61


1I I-- I7 I
Aug. Sept. Oct. Nov.


7.38 1 2.42 0.63 3.84


Apr.



3.24
1.55
6.74
2.68
5.36
5.00
0.99
4.51
3.15
7.28
0.57
3.42
0.00

3.42
7.28
0.00


4.58
3.58
1.08
6.20
2.47
5.29
4.11
11.30
2.01
6.11
4.46
4.25
1.81

4.13
11.30
0.63


12.02
8.16
14.66
5.66
2.83
8.32
10.83
8.59
9.85
11.36
5.47
2.00
3.73

7.92
14.66
2.00


Mar.


b.64
5.19
5.27
7.51
3.20
4.65
2.06
10.36
9.77
4.13
8.19
13.37
8.20

6.73
13.37
2.06


May I June


Year


1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938

Av.
Max.
Min.


Dec.


1.71


6.64
4.91
16.48
10.43
6.14
9.31
4.00
8.03
5.14
12.81
5.03
10.45
6.72

7.75
16.48
2.42


5.85
4.94
8.16
6.64
9.03
1.20
8.45
6.52
5.07
10.13
17.72
7.13
8.18

7.62
17.72
1.20


Annual
Total


50.89
36.49
62.04
53.27
44.24
45.78
46.62
59.11
50.10
59.06
61.56
55.71
39.92

51.15
62.04
36.49


1.45
0.51
1.05
2.92
0.96
0.96
5.64
3.17
0.54
0.61
5.24
1.45
1.77

2.15
5.64
0.51







TABLE 8.-EXCESSIVE PRECIPITATION AT THE EVERGL'ADES EXPERIMENT STATION 1935 TO 1938, INCLUSIVE.


Accumula
Date
1 hr. 2 hrs.

6/25/35 0.94 3.00
8/9/35 0.56 1.95
0,07 0.11
9/:/35 [ 0.62 0.90
1.16 1.23
6/3/36 2.10 2.45
( 0.11 0.38
6/15/36 I 1.80 2.12
3.24 3.70
11/6/36 0.10 0.10
) 1.71 1.74
11 /7/36 0.10 0.12
S1.88 1.96
11/12/36 0.10 1.25
1/13/37 0.10 0.14
3/31/37 0.98 1.96
S4.63 4.68
1/6/37 0.58 0.58
6/8/37 2.10 2.26
7/1/37 | 0.24 0.30
2.50
9/5/37 2.40 2.65
9/2/ 38 2.26 2.32


ted Amount


3 hirs.

3.73
1.97
0.18
0.92
1.33
2.62
0.62
2.44
4.11
0.10
2.24
0.17
2.00
3.45
0.84
2.25

0.73
2.37
0.30


s of Rainfall (in Inches) During Periods

4 hrs. 5 hrs. 6 hrs. 7 hrs_. 8 hrs. I

3.84
2.00
0.18 0.21 0.2:3 0.42 0.60
0.95 0.97 1 13 .16 1.16
1.50 1.51 1.52 1.83 2.01

0.82 (.98 1.08 1.17 1.43
2.52 2.66 2.85 3.00 3.10
4.14 4.18 4.22 5.38 6.55
0.20 0.20 0.22 0.22 0.82
2.45 2.52 2.54 2.79 3.05
0.30 0.31 0.31 1.10 1.68
2.07 2.09 2.10 2.10 2.12

1.40 1.77 1.78 2.14
2.58 3.92 4.36 4.50 4.50

1.37 2.33 3.28 3.38 3.84
2.44
0.32 0.70 1.19 2.20 2.42


Note. Rains of less than 2.00 inches in 24 hours are not shown. Tabulations of rains of more than 8 hours are shown in two or more line.
counceled by brackets. In such cases each amount in the second line includes the total for the eight-hour period in the line above.
The highest amount in a one- or two-hour period is not shown unless two inches or more fell in two consecutive hours.


Highest Amount
(in Inches)
1 hr. 2 hrs.


2.38


--- --









TABLE 9.-RAINS OF TWO INCHES OR MORE AT THREE STATIONS NEAR LAKE OKEECHOBEE.


Rain Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec.
(Inches)

Everglades Experiment Station, 1925 to 1938, Inclusive


2-3 2 -
3-4
4-5 -
5-6
6-7
8-12 -


U. S.


2-3 3 2
3-4
A-5; -


3 5 3
12
2 I
2 -


Cane Breeding Station,


1 7


5-6
6-7
7-8
21-22


9 3 5 o 2
4 1 1 2
SP 1 t I 3

1C



Canal Point, 1923 to 1938, Inclusive


5 13 2 1

2 2 -
S1 1


-I 1


Moore Haven, 1918 to 1938, Inclusive (see note)


10 7 6
2 2 4
2 1

1


Note.-There was no record at Moore Haven from Feb. to Sept. 1921, and from Sept. to Nov. 1926.


2-3
3-4
4-5
5-6
8-9


1


1
1


5
1

1


S3.
o
----
^+-
cc
----
f-
~L a
i^

re
c.


Ct/

a
---------C-+
's>






Water Control in the Soils of the Everglades


One of the heaviest 24-hour rainfalls ever recorded in Florida
occurred at Canal Point in November, 1932. The record at the
U. S. Cane Breeding Station showed 21.92 inches. Nearly all
the rain fell between 11:00 p.m. November 6, and 7:00 a.m.
November 7. During the preceding day 1.90 inches was re-
corded, making a total of 23.82 inches for 48 hours. Other rain
gages within a few miles of this station showed amounts varying
from 19.0 to 21.2 inches in 24 hours. The heaviest 24-hour rain-
fall at the Everglades Station was 10.90, during the same No-
vember storm. The maximum 24-hour rainfall recorded within
the state, 23.22 inches, occurred at New Smyrna in October,
1924.
Table 9 shows the number of rains of two inches or more
which have occurred in 24 hours at the Everglades Station, at
Moore Haven, and at Canal Point during the periods of record.
The number of rains are shown according to size groups as
indicated in the first column. The data show an average of
about four rains of two inches or more per year at each station
and approximately 60 percent of these rains have occurred dur-
ing the four-month period from June to September, when there
is little or no farming.
Rains of four inches or over have occurred eight times in 14
years at the Everglades Experiment Station; 13 times in 16
years at Canal Point; and seven times in 21 years at Moore Haven.

EVAPORATION AND TRANSPIRATION
To determine the evaporation and transpiration from sugar-
cane and grasses, records have been kept for the years 1934 to
1938, inclusive. For this purpose four large steel tanks were
used. Each tank is four by 12 feet in area by four feet deep
and is set in the ground to a depth of 3.5 feet. The bottoms of
the tanks were first covered with a three-inch layer of crushed
stone about one inch in size so as to allow the water table to
more readily equalize when water is added or withdrawn. The
excavated peat soil was replaced in layers to an elevation about
six inches below the tops of the tanks. The water table in the
tanks was kept at a near-constant elevation by adding or with-
drawing water as needed, using a two-inch bilge pump for this
purpose. The water added or withdrawn was measured in small
tanks of such size that an inch over the large tanks was equiva-
lent in volume to a foot in the smaller tanks. The rainfall was
measured in a standard rain gage placed nearby. The wind






Florida Agricultural Experiment Station


movement, shown in total miles per month, was recorded on the
top of a two-story building about 1,000 feet from the tanks.
The crops planted in the tanks were surrounded by other plant-
ings on the outside to protect the tank growth from an excessive
exposure to wind and sunlight and thus approximate fie'd condi-
tions as closely as possible. The open pan evaporation data were
obtained from a standard U. S. Weather Bureau open pan located
near the steel tanks. Tables 10 to 14 show the evaporation and
transpiration records for the years 1934 to 1938, inclusive.
The cane record covers a period of five years. The total
evaporation and transpiration for the four-month period from
June to September was approximately 49 percent of the total
for the five-year period and the total for the two-month period
from July to August was 27 percent of the five-year total. The
ratoon of cane cut in January does not reach much size till June
and the period of heavy growth extends through September.
During these summer months the days are long and the tem-
peratures high; hence the heavy evaporation. The average an-
nual loss from Tank 1, for the period of 1934 to 1937 inclusive,
was 46.8 inches. The 1928 record is not included as the ground
was kept heavily mulched during that year.
In field practice the cane is usually burned over before harvest
and after cutting the fields are fairly well covered with trash
from cane tops. This covering is probably a little thicker than
that on the tanks. The water table in the tanks averaged about
1.5 feet, while that in the cane fields probably averages about
two feet. Hence the field evaporation would be a little less than
the figures shown. It is estimated that the evaporation and
transpiration over large cane areas is between 42 and 45 inches
per year.
During the years 1937 and 1938 evaporation records were kept
for a tank covered with three or four inches of cane trash. The
water table averaged approximately 1.4 feet. The evaporation
for the first year was 12.2 inches and that for the second year
was 9.1 inches. The record for 1937 shows that the evaporation
from the mulched tank was about 30 inches less than that from
a bare soil tank which was partially shaded by cane around the
tank. During the year 1938 the cane tank was also covered with
a similar mulch of cane trash in order to determine the approxi-
mate transpiration through the cane. The results indicated
that 25.9 inches of the total loss from the cane tank was trans-
piration. The cane yield was 37.4 tons per acre. Calculations









TABLE 10.-EVAPORATION AND TRANSPIRATION FROM TANKS AND OPEN PAN FOR YEAR 1934, EVERGLADES EXPERIMENT
STATION, BELLE GLADE, FLORIDA.


Wind
Motion


Miles

4,600
5,070
5,650
4,950
4,100
3,860
3,330
3,410
3,540
3,980
4,250
4,220


Average Evaporation and Transpiration
Depth to Cane Cane Bare Soil Open
Water Tank 1 Tank 2 Tank 3 Pan
Feet Inches Inches Inches Inches


2.05
1.94
1.87
1.61
1.76
1.37
1.66
1.35
1.67
1.93
1.99
1.96


1.95
2.63
2.91
4.62
3.66
5.37
7.32
6.51
5.67
5.61
3.48
1.67


2.39
2.86
3.38
4.62
3.97
4.59
4.65
4.74
3.69
3.41
2.31
2.05


3.63
3.69
5.56
6.96
6.40
6.19
7.12
6.70
5.77
5.73
4.03
3.49


Mean
Rainfall Tempera-
ture
Inches F.

0.14 63.8
1.91 62.3
7.10 66.4
3.11 70.2
5.20 75,3
10.15 78.5
10.0! 79.2
12.41 80.0
7.44 79.6
3.22 76.1
0.65 68.0
0.82 63.8


Year ...................... 50,960 1.76 51.40 49.32 42.65 65.27 62.24 71.9

Note.-Cane in Tank 1 was a large barrel type (P.O.J. 2725) and that in Tank 2 was a medium barrel type (Co. 281). Both canes were planted
Feb. 1. 1934, and were cut Dec. 13, 1934. following a hard freeze on Dec. 12. Cane in Tank 1 produced 46.4 tons per acre and that in Tank 2 produced
33.0 tons per acre. Tank 3 contained bare soil without shade. Tanks 1 and 2 were surrounded with cane on the outside, for a windbreak.


Month


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


v











TABLE 11.-EVAPORATION AND TRANSPIRATION FROM TANKS AND OPEN PAN FOR YEAR 1935, EVERGLADES EXPERIMENT
STATION, BELLE GLADE, FLORIDA.

Wind Average Evaporation and Transpiration Mean
Month Motion Depth to Cane Cane Bare Soil I Alfalfa i Open Rainfall Tempera-
Water Tank 1 Tank 2 Tank 3 I Tank 4 Pan ture
Miles Feet Inches inches Inches Inches Inches IInches F.

Jan. ......... 5,179 1.80 0.93 0.87 2.08 1.74 3.81 0.30 63.4
Feb ......... 4,143 1.78 1.76 1.62 2.24 2.46 4.25 1.32 63.1
Mar. ......... 5,087 1.79 1.98 1.64 2.94 2.23 6.52 0.41 68.8
Apr. .......... 4,434 1.38 3.15 4.86 3.81 3.06 7.50 5.32 71.1
May ........ 4,073 1.82 2.94 2.73 2.79 4.22 8.84 1.08 76.1
June .......... 2,990 1.46 4.11 4.14 3.54 5.01 6.55 8.45 77.3
July ......... 3,851 1.67 5.83 6.26 4.16 6.70 7.38 6.37 79.3
Aug. ........ 2,956 1.55 6.54 7.16 4.37 7.28 7.02 6.54 80.1
Sept. ......... 4,111 1.28 5.64 5.28 5.55 3.69 5.54 10.88 79.1
Oct. .. 4,898 1.36 5.30 5.46 3.81 3.60 5.37 5.71 75.9
Nov. ......... 4,148 1.82 5.25 4.11 1.50 2.49 4.32 0.36 69.0
Dec. .......... 4,820 1.65 3.08 2.42 2.42 2.64 3.50 2.07 56.4


Year .......... 50,690 1.61 46.51 46.55 39.21 45.12 70.60 48.81 71.6

Note.-Cane in both tanks was the same type as in previous year. S il was covered with dry cane leaves until Jan. 21, thus reducing evaporation
for a period of three weeks. Cane growth was stopped by killing frost o Dec. 1 and crop was harvested on Jan. 14, 1936. Cane in Tank 1 was
retarded by wireworms. The yield was 42.0 tons per acre. Tank 2 was replanted on April 15. because of wireworm damage. The cane yield was
28.6 tons per acre.
Tank 3 contained bare soil partially shaded by cane around the outsi !e. but the shade was not equivalent to usual cane field conditions.
Tank 4 had soil substantially bare prior to April 15 when alfalfa was planted. At first the alfalfa made good progress but the stand deteriorated
during the summer, and only a scattered growth remained in the fall; he.ice the drop in evaporation.








TABLE 12.-EVAPORATION AND TRANSPIRATION FROM TANKS AND OPEN PAN FOR YEAR 1936, EVERGLADES EXPERIMENT
STATION, BELLE GLADE, FLORIDA.


Av. Depth to
Month Wind Water in Ft.
Motion Tanks Tank
1. 3 & 4 2
Miles

Jan ................ 4410 1.38
Feb. ............. 4994 1.21
Mar ........... 5050 1.42 *
Apr. ............ 4520 1.47 0.72
May ............. 4709 1.24 0.75
June ........... 3526 1.00 0.59
July ............ 3943 1.47 1.00
Aug ............ 3337 1.46 1.00
Sept .............. 2707 1.31 0.97
Oct .......... 3509 1.46 1.08
Nov. ........ 3755 1.14 0.86
Dec. .......... .. 3850 1.42 1.02


Year .......... 48,310 1.33 -


Evaporation and Transpiration

Cane Sawgrass Bare Soil Grass
Tank 1 Tank 2 Tank 3 Tank 4
Inches Inches Inches Inches

1.43 1.20 2.67
1.02 1.12 2.87
1.64 2.08 4.34
3.48 2.79 3.54 6.80
5.55 3.22 4.43 5.24
5.94 4.86 4.56 4.86
6.45 5.42 4.94 7.28
5.36 6.60 4.74 5.95
3.87 5.43 3.78 4.38
3.56 4.25 1.89 3.44
2.76 4.86 2.76 2.13
2.70 4.06 0.93 1.95


43.76 35.97 51.91


Open
Pan
Inches

4.18
3.81
6.22
7.68
7.40
5.94
7.37
6.54
4.92
5.15
4.28
3.13


66.62


Mean
Rainfall Tempera-
ture


Inches

1.91
4.04
2.40
1.96
6.39
18.61
6.09
5.33
5.84
1.65
9.17
1.18


64.57


F.

65.1
63.5
65.5
70.6
73.8
77.0
81.1
80.6
79.3
78.1
68.0
67.0


Note.-Cane (F31-1037) was cut Dec. 29, 1936. Yield of mill cane w s 28.4 tons per acre and 205 lbs. of 960 sugar per ton.
Sawgrass was set in Tank 2 on Mar. 3. By May 1 old sawgrass had died down and new sprouts appeared. Stand did not reach full size until
Nov. Thereafter a good stand was maintained.
Soil in Tank 3 was partially shaded during year by cane around tank.
Tank 4 was planted to Alfalfa on Jan. 29. Stand died down by summer and was mostly grass and weeds during last half of year.
*No record.












TABLE 13.-EVAPORATION AND TRANSPIRATION FROM TANKS AND OPEN PAN FOR YEAR 1937, EVERGLADES EXPERIMENT
STATION, BELLE GLADE, FLORIDA.


Ja
Fe


Wind Av. Del
Month Motion Water
Tanks
S__1, 3&4
Miles

n. ................ 4076 1.28
b. .. ............ 4283 1.47


M ar. ............
A pr. ..............
M ay ..............
June
June ... .........
July ...............
Aug. ....
Sept.. .. .......
Oct.......-
N ov ...........
Dec .-...........


Y ear ...........


1 4235
4037
3275
S 2978
S 2914
S 2853
S 2812
3345
4418
4275


.43,501


th to
in Ft.
Tank Cane
2 Tank 1
Inches

0.77 1.73
1.05 2.46
1.06 3.36
0.84 4.63
1.04 5.85
0.77 4.33
0.96 5.43
0.88 5.24
0.95 4.79
0.93 3.44
0.93 2.49
0.99 1.67


1.34 0.93 45.42


Evaporation and Transpiration


Sawgrass
Tank 2
Inches

5.61
4.93
6.24
7.53
9.64
7.05
9.95
8.80
8.93
7.60
4.14
3.62


SRainfall


Bare Soil Mulch Soil| Open
Tank 3 Tank 4 Pan
Inches Inches Inches Inches

1.75 0.53 4.44 2.97
2.91 0.66 3.86 1.21
3.78 0.71 5.30 5.87
4.26 1.06 6.30 6.00
4.54 1.05 7.77 3.38
4.53 1.18 6.70 7.74
5.09 2.05 6.66 7.65
4.99 1.48 6.02 7.89
4.38 1.39 5.58 8.35
3.20 1.10 4.93 4.92
1.44 0.55 3.76 2.08
1.41 0.43 3.12 0.38


84.04 42.28 12.19 64.44 58.44


Mean
Tempera- .
ture

F.

70.8
64.7
66.1
70.0
74.0
78.3
79.7
80.6
78.9
73.8
67.1
63.2


72.3
o
-------


Note.-Cane (F31-1037) was cut Dec. 17. Yield of cane was 20.0 tons per acre and 219 lbs. of 96 su-car per ton. Stand was poor probably due
to wire worms. Sawgrass fully grown and shaded by cane around tank. Stand probably equal to average in Glades. Bare soil partially shaded by
cane around tank. About 4 inches of cane leaves used for mulch on Tank 4.








TABLE 14.-EVAPORATION AND TRANSPIRATION FROM TANKS AND OPEN PAN FOR YEAR 1938, EVERGLADES EXPERIMENT
STATION, BELLE GLADE, FLORIDA.

Wind Av. Depth to Evaporation and Transpiration Mean
Month Motion Water in Ft. Rainfall Tempera-
Tanks Tank Cane Sawgrass Grass Mulch Soil Open ture
1, 3 & 4 2 Tank 1 Tank 2 Tank 3 Tank 4 Pan CJ
Miles Inches Inches Inches Inches Inches Inches F.

Jan. ...... 4140 1.60 0.78 0.56 4.01 0.56 3.69 0.46 62.5
Feb ......... 4685 1.45 0.90 0.62 4.17 2.87 0.5) 4.22 1.14 65.4
Mar. ..... 3833 1.43 1.02 0.73 6.49 4.93 0.43 5.85 1.87 68.9
Apr. ...... 4300 1.51 1.04 1.29 7.:2 5.27 0.46 6.78 0.32 69.8
May 3224 1.37 0.92 2.33 7.69 6.98 0.76 6.66 4.52 75.8
June 2913 1.39 0.90 3.93 7.59 7.26 1.11 6.50 5.44 77.6
July ... 3188 1.26 0.94 5.70 6.72 5.63 1.65 6.64 8.85 79.0
Aug ...... 3062 1.45 1.00 6.00 7.05 5.80 0.59 6.75 2.65 79.8
Sept. 2961 1.36 0.88 5.46 5.99 4.65 1.08 5.92 10.09 78.6
Oct. ......... 4220 1.43 0.95 3.45 5.09 4.34 0.78 5.34 2.78 72.5
Nov. ... 3663 1.39 0.90 2.67 3.48 3.57 0.81 4.08 2.66 71.2
Dec. .......... 3554 1.50 0.96 2.29 2.25 2.69 0.28 3.36 0.21 63.7


Year ......... 43,743 1.43 0.93 35.03 67.85 53.99 9.10 65.79 40.99 72.1

Note.-Cane (F31-436) was planted last week of Dec., 1937, and cut Jan. 3. 1939. Yield was 37.4 tons per acre. Both Cane Tank I and Mulch
Tank i were covered with a heavy layer of cane trash during the year. The difference between the total evaporations of the 2 tanks or 25.93 inches
is roughly the transpiration loss through the cane. This amounted to 78.4 pounds of water per pound of mill cane, and 763 pounds of water per
pound of 96 sugar.
The sawgrass in Tank 2 was surrounded by cane for a windbreak. The stand of sawgrass was below normal during the last half of year. Tank
3 was planted to Bahia grass in January. The grass was not cut during the year.
*No record.





Florida Agricultural Experiment Station


by Mr. F. D. Stevens, sugarcane agronomist, Everglades Station,
showed that the transpiration amounted to 78.4 pounds of water
per pound of mill cane, and 763 pounds of water per pound of
960 sugar.
The four-year evaporation record from the uncropped and un-
mulched tank showed an average loss of 40 inches per year. The
difference between the several years is doubtless due, in part,
to variation in the amount of shading and probably also to varia-
tion in frequency of rainfall. When the surface soil is kept wet
by frequent rains evaporation increases.
On January 29, 1936, one of the tanks was planted to alfalfa
but the stand died down by summer and was mainly grass and
weeds during the last half of the year. Evaporation and trans-
piration for 11 months exclusive of January totaled 49.2 inches.
On January 3, 1938, a tank was planted to Bahia grass. The
grass grew well and was not cut during the year. Cane was
planted around the tank as a windbreak. The water table aver-
aged 1.4 feet. Evaporation and transpiration for 11 months,
exclusive of January, were 54.0 inches. The estimated total
for a full year was 57 inches. It is evident that the losses from
grass land are very high.
To secure data with which to estimate the evaporation from
the sawgrass land of the Everglades, the sawgrass plants from
an area of 4x12 feet were transplanted in a tank of the same
area in March, 1936. By May 1 the old sawgrass had died down
and new sprouts appeared. These did not reach full size until
November. Through the year 1937 the stand was equal to that
on the land from which the plants were taken. Cane was planted
around the sawgrass tank to serve as a windbreak. The water
table averaged nearly a foot in depth. Evaporation and trans-
piration for the year 1937 amounted to 84 inches.
During the last half of the year 1938 the sawgrass deteriorated
to a considerable extent, but was probably somewhat better than
the average stand on the virgin areas of the Everg'ades. Evap-
oration and transpiration for the year amounted to almost 68
inches.
There are very few data on average depth of water table in
the sawgrass area of the Everglades. The water table may vary
from surface to a depth of four feet or more. It probably aver-
ages about two feet. Annual evaporation from the Everglades
would be somewhat less than that from the tank, due to the
deeper water table and also a little better protection from wind.






Water Control in the Soils of the Everglades


After making some allowance for these differences it is estimated
that the mean annual evaporation from the sawgrass lands aver-
ages about 60 inches. As this is substantially more than the
average rainfall of approximately 53 inches, the results indicate
that run-off and seepage from outside areas are a considerable
factor in maintaining the water table beneath the peat lands
of the Everglades.
Evaporation records from a standard Weather Bureau open
pan have been kept by the Everglades Station since 1924. The
records for the years 1934 to 1938 show a five-year average loss
of 66.54 inches. This evaporation is considerably higher than
that from a large open body of water such as a lake. Experi-
ments, in the arid West, conducted by the Irrigation Division
of the Soil Conservation Service, USDA,6 indicated that the
evaporation from large bodies of open water is approximately
70 percent of that from a standard Weather Bureau open pan.
If this ratio also holds for the humid region, the mean annual
evaporation from a large body of water such as Lake Okeechobee
would approximate 47 inches.

TEMPERATURE
The mean annual temperature at the Everglades Station for
the five-year period of 1934 to 1938 was 72.10 F. August was
the warmest month with an average of 80.2 and December was
the coldest with an average of 62.80 for the five-year period.
The Everglades Station has kept a record of temperatures since
July, 1924. The maximum of 100 was reached three times in
July, 1931. The minimum recorded at a height of four feet
above the ground was 250 on January 15, 1926, and again on
December 13, 1934. The record shows that temperatures of 320
or less were experienced 12 times in December, 11 times in Jan-
uary, three times in February and six times in March, during a
period of 14 years.
The Everglades Station has kept a record of minimum tem-
peratures from a point near the Hillsboro locks west of Belle
Glade to Twenty Mile Bend on the West Palm Beach Canal. The
thermometers are located near State Highway 25 and are set
in boxes about four feet above the ground. Table 15 shows the
readings at the several stations for periods when the minimum
at the Experiment Station was 380 or less. Readings at the
SRohwer, Carl. Evaporation from free water surfaces. U. S. Dept.
Agr. Tech. Bul. 271. 1931.






Florida Agricultural Experiment Station


Experiment Station, 4.3 miles below the Hillsboro lock, are taken
each day, but those at the other stations were usually read once
a week during the cold portion of the year. The readings are

TABLE 15.-MINIMUM TEMPERATURES ALONG HIGHWAY NO. 25 FOR PERIODS
WHEN MINIMUM WAS 38 F. OR LESS AT THE EVERGLADES EXPERIMENT
STATION FROM DECEMBER, 1929, TO MARCH, 1938.

Date Distance from Hillsboro Lock No. 1 in Miles
0.2 1.3 1 2.6 4.3 8.4** 13.5** 21.5**


12/26/29 ..... 38.0 34.0 32.5 33.5 27.0 28.0 27.0
1/31/30 ............ 38.0-* 38.0- 35.0- 36.0- 31.0-
3/5/30 .......... 30.0 28.0 30.0 30.0 26.5 26.0 21.0
11/26/30 .... 37.0 36.0 36.0 35.0 34.5 32.0 33.0
12/10/30 .......... 31.0 28.5 29.0 28.5 23.0 23.0 23.0
12/15/30 .......... 38.5- 34.0- 34.0- 35.5- 30.0- 28.5-
12/24/30 ......... 41.0- 39.0- 40.0- 34.0- 32.0- 31.0-
12/28/30 ....... 38.5 35.0 35.0 35.0 32.0 32.0 30.0
1/7/31 ............ 35.0 31.5 30.0 29.0 23.5 22.5 20.5
1/15/31 .. ...-..... 38.5- 38.0- 37.5- 36.5- 35.0- 35.0-
1/22/31 ......... 39.0 38.0 37.0 32.0 32.0 34.0 31.0
3/5/31 .............. 34.5 33.0 33.0 32.0 27.0 29.5 27.5
3/12/31 ............ 45.0 44.0 41.0 30.0 34.0 35.0 35.0
4/8/31 ............ 39.0 35.5 32.5 33.0 28.0 31.0 28.0
10/10/32 ......... 43.0 37.0 37.5 37.0 37.0 32.0 30.0
3/14/32 ....--....- 35.0 30.0.0 0.0 32.0 27.0 28.0 25.0
1/29/33 .......... 32.5 28.5 30.0 34.0 28.5 32.0 28.0
2/6/33 ............. 36.0 31.0 34.0 35.0 28.0 30.0 31.0
3/4/33 ............ 34.0 29.0 31.5 34.0 24.5 29.0 27.0
1/11/34 ........... 45.0 37.0 35.5 37.0 34.5 33.0 28.0
1/31/34 ........... 42.0 38.0 35.0 38.0 37.0 31.0 31.0
2/3/34 ............ 41.0 34.5 37.0 36.0 26.0 27.0 26.5
3/12/34 .......... -- 132.0- 34.0- 34.5- 33.0- 30.0- 29.0-
12/13/34 ........ 26.5 27.0 23.0 25.0 18.0 13.0 13.0
12/14/34 ........ 40.0 35.0 36.0 37.0 30.0 29.0 25.0
1/24/35 ...-.. 41.0 39.5 38.0 36.0 32.0 30.0 28.0
2/5/35 ....... ..... 32.0 30.5 30.0 31.0 21.5 27.0 28.0
2/21/35 .-..--...- 38.5 37.0 35.0 38.0 30.0 30.0 27.0
2/28/35 ......... 39.5- 39.0- 37.0- 31.0- 25.0- 26.0-
12/1/35 ........... 30.0 30.0 31.5 34.0 26.0 27.0 26.5
12/19/35 ......... 35.5 32.0 32.0 34.0 27.0 27.5 28.0
12/21/35 ....... 30.0 30.0 30.0 30.0 25.0 24.5 24.5
2/1/36 .......... 38.0 37.5 36.0 36.0 33.0 30.5 31.0
2/11/36 .......... 36.0 36.0 35.0 37.0 33.0 28.0 33.0
3/19/36 ............ 37.0- 36.0- 36.0- 1 36.0- 33.0- 36.0- -
3/22/36 ........... 34.0 33.5 34.0 35.0 29.0 35.0 37.0
11/28/36 --....-... 41.0 -- -- 34.0- 36.0- 36.0-
2/6/37 ........... 33.0- 33.5- 37.0- 27.0- 30.0- 30.0-
11/21/37 .......... 40.0- 40.0- 36.0- 36.0- 34.0- -
12/7/37 ....-..... 32.0- 32.0- 29.0- 31.0- 28.0- -
1/28/38 .......... 30.0- 30.0- 28.0- 32.0- 24.5- 26.0-
2/26/38 .........- 39.0- 37.0- 38.0- 34.0-


Average .......... 36.5 33.7 33.3 33.6 28.8 28.8 27.7

*Readings marked (-) are not included in averages.
**Locations at Miles 8.4; 13.5; and 21.5 were in areas of virgin sawgrass.





Water Control in the Soils of the Everglades


the minimums for the period covered and when the minimum
for the period was 38 or less at the Experiment Station the
corresponding readings at the several stations are shown as of
the same date. For this reason all readings of 38 or less at
the Experiment Station are not shown, for if the minimum were
380 for one day of the period and 35 for another day only the
lowest reading would be shown.
The table shows the change in minimum temperatures with
distance from Lake Okeechobee. The stations at 0.2, 1.3, 2.6,
and 4.3, miles from the lock are on cultivated ground while those
at 8.4, 14.0, and 21.5 miles from the lock are on virgin land.
The lock is 1.3 miles from the new lake levee. The data indicate
that low temperatures at the lock average nearly 30 warmer
than those at the Experiment Station (4.3 mi.) and nearly 90
warmer than those at Twenty Mile Bend (21.5 miles). There
is reason to believe that these low temperatures in the virgin
land would be 3 or 4 higher if the land were in cultivation. The
very loose top soil and mulch of leaves and trash on the virgin
land acts as an insulating cover which retards the flow of heat
from the wet soil beneath to the air above.
The Shawano Plantation is located on the Hillsboro Canal
about 11 miles southeast of the Everglades Experiment Station.
A record of temperatures on the cultivated areas in that loca-
tion is available since January 1, 1929. A comparison of the
minimum readings of 38 or less at the Experiment Station
with those at Shawano shows those of the latter station to aver-
age 1.1 lower than at the Experiment Station. However, the
difference is somewhat greater when the comparison is confined
to very low temperatures. From January, 1929, to March, 1938,
a tabulation of temperatures, when the minimum was 320 or
less at either of these stations, showed an average difference of
2, while the minimum readings on cultivated land near Glade-
view (13.5 miles) showed a difference of 4.8'. As the station
near Gladeview is about the same distance from Lake Okeechobee
as that at Shawano, the comparison indicates that temperatures
of 380 or less will average from 3 to 4 higher after the virgin
land is placed in cultivation.
On March 14, 1932, a minimum temperature of 9 was re-
corded on a thermograph located one foot above ground on virgin
sawgrass land at the Shawano plantation. The water table was
very low in the soil at that time and the Glades very dry and





Florida Agricultural Experiment Station


covered with a deep mantle of dead weeds and sawgrass from
earlier frosts.
On December 13, 1934, two readings of 13 were recorded on
virgin land (see Table 15). One was 13.5 and the other 21.5
miles east of the Hillsboro locks along State Highway 25. A
minimum thermometer set by the Everglades Station 15 miles
below South Bay and 600 feet west of the North New River
Canal on virgin land recorded a low of 14.00 on or about March
5, 1930.
These records indicate that very low temperatures occasionally
occur in the virgin areas east and south of Lake Okeechobee.
It is probable that higher minimum temperatures would result
if the water tables in the outer areas could be held near or above
the surface.

WATER CONTROL BY PUMPING
The early drainage of the peat lands around Lake Okeechobee
depended on gravity systems discharging into the large outlet
canals, which were never entirely completed. Due to the flat
topography the ditch gradients are only a few inches per mile
and hence the water movement is very slow. The subsidence
following original drainage further reduced the effectiveness of
the gravity systems. To improve their drainage nearly all the
sub-districts in the northern Everglades have installed large
pumps, and many farmers also have installed private pumps to
increase the effectiveness of their water control. The first large
pumping plants were built in 1925. As most of the pumps are
reversible, water as needed may be pumped into the areas served
and thus control the water levels during dry periods. The
majority of the large plants are located near Lake Okeechobee
and discharge into the lake; however, a few are located farther
back on the large canals and the water from these may run either
into the lake or down the canals, depending on the relative lake
and canal stages. The amount of pumping varies widely from
year to year, depending largely on the amount of rainfall. There
is little pumping from November 1 to June 1, the dry portion
of the year.
Nearly all the large plants use the screw type pumps with a
capacity of from 30,000 to 60,000 gallons per minute, but in
recent years a few large vertical turbine pumps of 30,000 to
40,000-gallon capacity have been installed. The large screw
pumps are driven by heavy duty diesel engines of from 80 to





Water Control in the Soils of the Everglades


180 horsepower and one large vertical turbine pump uses a 125
horsepower electric motor. This particular pump is operated
under an off-peak contract and the cost of power has averaged
approximtaely 1.8 cents per k.w.h.
The drainage districts of the northern Everglades have in-
stalled pumping plants with a total rated horsepower of approx-
imately 5,500 and a total capacity of approximately 4,200 second
feet. The average static lift is probably close to four feet and
the maximum lift has seldom reached eight feet. The discharge
capacity of most of the large pumping plants is approximately
one inch in 24 hours over the area served, but a few have capaci-
ties of 1.5 inches. In addition to the large plants there are a
number of small plants serving areas of 80 to 640 acres. These
are usually privately owned. Many of them are located within
the areas served by the district pumps and provide additional
facilities for controlling the water table on individual farms. The
capacities of these smaller pumps usually range from 1.5 to 3
inches. Approximately 100,000 acres in the northern Everglades
are served by pumps and about 85 percent of this acreage is in
agricultural use.
Approximately 60 percent of the rainfall near Lake Okee-
chobee occurs during the four-month period of June to Septem-
ber, and by far the greater part of the pumping is done during
these months. During the late winter and spring months a small
amount of water is pumped into the districts to raise the water
table. This will probably not average over six inches and will
seldom exceed 12 inches in the driest years. A comparison of
the amount pumped with the estimated difference between rain-
fall and evaporation indicates that seepage accounts for a large
portion of the water pumped from a drainage area.

DESCRIPTION OF PUMPING PLANTS
During the six-year period of 1933 to 1938, inclusive, pumping
records have been kept on four large plants near Canal Point
and on one small plant at the Everglades Station. The locations
of these plants are shown in Figure 1. The four large plants
located in the Pelican Lake and Pahokee drainage districts are
fairly typical of the larger plants around Lake Okeechobee. They
have a discharge capacity of one inch in 24 hours and may be
reversed to supply irrigation water when needed. The cultivated
acreage is largely planted to sugarcane, but a substantial amount
is used for truck crops. All four plants pump directly into the





Florida Agricultural Experiment Station


West Palm Beach Canal and the amount of pumping is consider-
ably affected by the canal stage. The small plant at the Ever-
glades Station near Belle Glade discharges directly into the Hills-
boro Canal. This area served is planted to experimental crops
of cane, truck and grasses. A larger amount of pumping is done
through the summer than is usual on other land. Figure 6 shows
a typical pumping plant of the northern Everglades.



















Fig. 6.-A typical large pumping plant of the northern Everglades.
Such plants contain from one to three pumps of approximately 56,000
gallons capacity each.

Pelican Lake Unit No. 1.-The two engines are each 80 horse-
power, vertical, two-cylinder, type Y, diesels, made by Fairbanks-
Morse and Company, and are directly connected to the pumps.
The full speed is 300 revolutions per minute, but this can be
varied by special adjustments. The two pumps are each 42-inch
Wood-screw type, with a rated capacity of 30,000 gallons per
minute. The pump house is made of corrugated metal on timber
framework and is set on a concrete foundation. The total cost
of the plant was $55,000. Pumping operations were started in
1925.
Fuel oil consumption during the six-year period has averaged
1.14 gallons per acre-foot pumped, and 5.2 gallons per pump-hour
of operation. The static lift has averaged 3.5 feet and the maxi-
mum lift was 7.1 feet. The plant-days of operation during a
year has averaged 68.3. As one or more pumps in a given plant






Water Control in the Soils of the Everglades


may be operated during the day, a plant-day is determined by
adding together the total days of operation of each pump during
the year and dividing the result by the number of pumps.
Pelican Lake Unit No. 2.-This plant is similar to Pelican
Lake Unit No. 1. The total cost of the plant was $51,000.
Pumping operations were started in July, 1929.
Fuel oil consumption during the six-year period has averaged
1.05 gallons per acre-foot pumped and 5.2 gallons per pump-
hour of operation. The static lift has averaged 3.9 feet and the
maximum lift was 7.5 feet. The plant-days of operation during
a year has averaged 44.2.
Figure 7 shows the record of pump operations at the two
Pelican Lake plants for the year 1934. Similar charts have been
prepared for the other five years of record. Copies of these

JIr M pr ) .t U -e ov e



1 -
ur," ,I,'s' C a I 'ac a,' atpu # 1-Ln 'o I


Fig. 7.-Record of pumping plant operation at Pelican Lake Drainage
District, Florida, 1934. Total water pumped for drainage: Unit No. 1,
23,764.2 acre-feet (7.03 feet on 3,379 acres); Unit No. 2, 14,287.2 acre-feet
(5.01 feet on 2,853 acres). Total rainfall (both units), 69.78 inches or 5.82
feet. Total fuel oil used: Unit No. 1, 26,300 gallons; Unit No. 2, 15,985
gallons. Average lift of pumps: Unit No. 1, 3.3 feet; Unit No. 2, 4.3 feet.


Ij. .. J lJ





Florida Agricultural Experiment Station


may be obtained from the Soil Conservation Service, U. S. Dept.
of Agriculture, Washington, D. C. Total amount of pumping,
depth over the drainage area, rainfall, fuel oil used, and average
lifts are shown for each plant. During the year 1934 Unit No. 1
pumped approximately seven feet from the drainage area, and
Unit No. 2 pumped five feet. This difference is mainly due to
the heavy seepage into the area of Unit No. 1 from undrained
lands to the east. There is a large area of virgin land between
the St. Lucie and West Palm Beach canals, much of which drains
to the south. A high water table in lands outside of a pumped
area materially increases the amount of pumping. A high stage
in the West Palm Beach Canal also increased the pumping in
each of these units, due likewise to seepage which reaches the
pumped area through the porous limestone and sand beneath
the peat. This seepage probably has little effect on the maxi-
mum rate of pumping, but prolongs the pumping period.
The rainfall at Azucar, located between the two Pelican Lake
units, will probably differ little from the average over the two
drainage areas. For the years 1933 to 1938, inclusive, the an-
nual amounts were 61.1, 69.8, 52.5, 57.8, 55.7 and 39.3 inches,
respectively. The average was 56.0 inches.
If the rainfall, evaporation and depth pumped for a given
area are known, an approximate estimate may be made of the
seepage during a year. Azucar is located near the center of
Unit 2 of the Pelican Lake District and all land is within two
miles of the rain gage. Nearly all the land is in sugarcane.
Records at the Everg'ades Station indicate that the annual evap-
oration from such an area approximates 3.5 feet. The rainfall
for 1936 was 4.82 feet, which is close to normal, and the depth
pumped was 4.09 feet. These data indicate that the seepage
inflow was equivalent to a depth of 2.77 feet. The average
annual seepage depth for the six-year period was 2.5 feet. A
large area under similar conditions would show a smaller depth
of seepage.
East Pahokee Unit No. 1.-The two engines are each 180
horsepower, vertical, three-cylinder, type Y, diesels, made by
Fairbanks-Morse and Company, and are directly connected to
the pumps. The full speed is 257 revolutions per minute and
this can be readily reduced by a speed control mechanism on each
engine, so that a fairly constant canal stage can be maintained
at the pump intake. The two pumps are each a 54-inch Wood-
screw type with a rated capacity of 60,000 gallons per minute.





Water Control in the Soils of the Everglades


The pump house is made of corrugated metal on steel frame-
work, and is set on a concrete foundation. The total cost of the
plant was 875,000. Pumping operations were started in No-
vember, 1929.
Fuel oil consumption during the six-year period has averaged
0.96 gallons per acre-foot pumped, and 6.8 gallons per pump-hour
of operation. The static lift averaged 4.4 feet and the maximum
lift was 7.5 feet. The average lift for the year 1938 was 2.9
feet. This low lift was due to the fact that the West Palm Beach
Canal was at a very low stage during the year and a!so because
there was considerable pumping for irrigation in December when
there was little or no lift. Some water was siphoned into the
district through the pumps with the engines disconnected. The
plant days of operation during the six-year period has aver-
aged 39.5.
East Pahokee Unit No. 2.-The equipment of this plant is
similar to that of East Pahokee Unit No. 1, except that there
are three engines and pumps instead of two. The total cost
of the plant was 8105,000. Pump operations were started in
January, 1930.
Fuel oil consumption during the six-year period averaged 0.91
gallons per acre-foot pumped and 7.7 gallons per pump-hour of
operations. The static lift averaged 4.1 and the maximum lift
was 7.6 feet. The average lift for the year 1938 was 2.3 feet.
This low lift was due to the low stage of the West Palm Beach
Canal and also to the large amount of pumping for irrigation
in April, May and December, when the lift was very low. The
amount pumped for drainage in 1938 was 7,757 acre-feet and
that pumped for irrigation was 11,039 acre-feet. The plant-days
of operation during the six-year period averaged 40.0.
Figure 8 shows the record of pump operations at the two East
Pahokee plants for the year 1934. Similar charts have been
prepared for the other five years of record. Copies of these may
be obtained from the Soil Conservation Service, Washington,
D. C. The amount pumped, depth over the drainage area, rain-
fall, fuel oil used, and average lift are shown for each plant.
The records indicate that the stage in the West Palm Beach
Canal has a substantial effect on the amount of pumping. This
is particularly evident when a comparison is made of the pump-
ing in August and October, 1935.
The drainage areas of these two units are not completely
separated, as a ditch at the west end of the district may carry






44 Florida Agricultural Experiment Station

water to either unit. The six-year record for Unit 1 shows an
average annual depth pumped for drainage of 2.26 feet and for
irrigation of 0.004 feet. The record for Unit 2 shows 2.25 feet
pumped for drainage and 0.30 feet for irrigation. The two units
combined show 2.26 feet pumped for drainage and 0.20 feet for
irrigation. In 1938, the driest year of record, Unit 2 pumped
0.82 feet for drainage and 1.16 feet for irrigation. The rainfall
near the center of Unit 1 for the years 1933 to 1938, inclusive,
was 64.57, 66.20, 49.36, 57.45, 53.84 and 33.72 inches, respec-
tively. The average was 54.19 inches. There was no rain gage
in Unit 2, but the rainfall will probably differ little from the
above.
A comparison of the depth pumped by Pelican Lake Unit No. 1

S Jaen. O ret March Api May u Sept t. N-O ec.






400
S400 -




?,------,----- ---r ----- -------

300 _- -




i3 ..a L Iaoai- i ,oo.,+: x o o



S 0 3 6 40 7. 63 8 O" 6.4!" 11 0" 1405" 2.3" 0.30
o ... ,, 0 1


Fig. 8.-Record of pump operation at East Pahokee Drainage District,
Florida, 1934. Total water pumped for drainage: Unit No. 1, 16,588.0 acre-
feet (2.86 feet on 5,798 acres); Unit No. 2, 30,270.8 acre-feet (3.20 feet on
9,478 acres). Total rainfall (both units), 66.20 inches or 5.52 feet. Total
fuel oil used: Unit No. 1, 17,500 gallons; Unit No. 2, 32,087 gallons.
Average lift of pumps: Unit No. 1, 4.7 feet; Unit No. 2, 4.7 feet.





Water Control in the Soils of the Everglades


with that of East Pahokee Unit No. 1 shows that the six-year
average for the former plant was almost twice that of the latter
plant. The effect of a high water table outside of a pumped area
is here clearly shown. Pelican Lake Unit No. 1 abuts on virgin
land to the east in which the water table is usually high due to
seepage from higher lands. On the west it abuts on the sandy
ridge along Lake Okeechobee whose average stage is as high as
the lands in the pumped area. The East Pahokee Unit No. 1
adjoins pumped lands to the north, south and west. Both areas
have about the same frontage on the West Palm Beach Canal.
Everglades Experiment Station Plant.-The electric motor is
a four-speed Westinghouse, type C. S. induction model. It is
rated from 4.2 to 30 horsepower, depending on the speed used,
and is connected to the pump by a set of short V-belts. The
four speeds are 445, 590, 890 and 1,180 revolutions per minute.
However, nearly all the operation has been at the third speed
of 890 revolutions per minute. A small amount of pumping
has been done with an oil engine, but the energy so used has
been estimated in equivalent kilowatt hours and added to the
totals shown for the electric motor.
The pump is a 24-inch vertical turbine rated at 10,000 gallons
per minute at high speed, and is so built that water can be
pumped either in or out of the area, served by the simple opera-
tion of four vertical slides. It was made by the Couch Manu-
facturing Company and has four speeds of 217, 292, 442 and 574
revolutions per minute. The pump is started and stopped by an
automatic float in the intake ditch, and requires little attention
during operation. The pump house is made of corrugated metal
on steel framework and is set on a concrete foundation. The
total cost of the plant was approximately $3,400. It began
operating in July, 1931.
The electric power used is three-phase, 60-cycle, 220-volt cur-
rent. The cost of power up to July 1, 1936, was based on a
charge of $4.00 per "contract" horsepower for the first 25
"contract" units per month for four months in each yearly
period; $3.00 per horsepower for all additional "contract" horse-
power per month for four months in each year; and 3 cents per
kilowatt-hour for all energy used per month. Since July 1, 1936,
the plant was operated under a new contract, but the cost of
power was reduced only a very small amount, although the basis
of calculating the cost was changed.






Florida Agricultural Experiment Station


The record covers a six-year period. During the first three
years the area drained was 162 acres, but after that period an
additional 40 acres was added to the farm. This new land may
drain either to the South Florida Conservancy District pump or
to the Experiment Station pump. It is estimated that approxi-
mately 180 acres are now served by the Experiment Station pump
and the cost estimates for the last three years are based on that
area. The annual cost of electric power during the six-year
period has averaged $3.90 per acre served and 6.1 cents per k.w.h.
used. The average period of operation has been 49 days per
year. The annual rainfall for the six-year period varied from
65.3 to 41.0 inches and averaged 56.7 inches. The static lift has
averaged 2.1 feet and the maximum lift was 4.2 feet. The record


L i




QI 0

2r 4
oI.

070i
lo


T.;



2: .1 i-


r- 1- A--I-i--





--4"
401

0 40 3 00r 9 2 257.h 1 03 *h 4359sXlT(J1 3294r ;1003 *~h 40


6 0 0 2


Fig. 9.-Record of pump operation at Everglades Experiment Station,
Florida, 1934. Total water pumped for drainage, 1,411.1 acre-feet (8.71
feet on 162 acres). Total water pumped for irrigation, 87.7 acre-feet (0.54
feet on 162 acres). Total time of pumping, 1,338 hours (55.8 days). Total
energy used, 12,665 k.w.h. Total cost of electric power, $780. Average
lift of pump, 2.32 feet.


,,,,,, ...r






Water Control in the Soils of the Everglades


for the six years shows an average annual depth of 6.9 feet
pumped out for drainage and 0.65 feet pumped in for irrigation.
Figure 9 shows the record of pump operation at the Everglades
Station for the year 1934. Similar charts have been prepared
for the other years. Copies of these may be obtained from the
Soil Conservation Service, Washington, D. C. The amount
pumped, depth over the drainage area, kilowatt hours used, rain-
fall, and stages of the Hillsboro Canal are shown for each year.
The charts show that the amount of pumping is increased
when the Hillsboro Canal is at a high stage. During May, 1936,
with a rainfall of 6.4 inches and an average canal stage of 12.9
feet, only 12 acre-feet were pumped for drainage while in July
with a rainfall of 6.1 inches and a canal stage 3.8 feet higher,
407 acre-feet were pumped. This increase indicates the effect of
a high water table outside a cultivated area on the amount of
pumping. This, however, is an extreme case, as the variation
in outside water table is seldom so wide. The Experiment Sta-
tion area has a frontage of over a mile on the Hillsboro Canal
and due to the use of the land for experimental purposes more
pumping is done in the summer than is the case with ordinary
farm land. These conditions account for the large annual amount
of pumping. A small quantity of water is run into and out of
the area by gravity, but it is estimated that the quantities will
about balance. From evaporation experiments with sugarcane,
grass, bare soil, and open water it is estimated that the annual
evaporation from the Experiment Station farm will approximate
3.5 feet. This figure, used with the amount pumped and the
rainfall, indicates a seepage inflow varying from two to seven
feet per year and averaging five feet. As previously stated, the
seepage will depend on the water table in surrounding lands and
on the stage of the Hillsboro Canal.

FIXED AND OPERATING COSTS OF PUMPING
The installation costs and fixed charges for each pumping
plant are shown in Table 16. The term "fixed charges" as used
in this report includes the annual interest on the capital invested
and the annual depreciation charge. The interest on invested
capital is figured at 6 percent. The depreciation charge has been
computed by the sinking fund method and the annual charge is
such an amount that, invested at 4 percent compound interest,
the sum of the payments and the interest will equal the cost
of the building and equipment at the end of their estimated life.







Florida Agricultural Experiment Station

TABLE 16.-FIXED CHARGES OF PUMPING PLANTS.

Cost Intere
Plant Engines Depre- at 6
Building and Total ciation Perce:
Pumps

can Lake
S-N 1 I o 2n \n rAfn Ir r nnn q1i Q47 3 7 30


Pelican Lake I
Unit No. 2
East Pahokee
Unit No. 1
East Pahokee
Unit No. 2
Everglades
Experiment
Station


20,250 30,750


32,000

40,000


1,900


43,000


51,000

75,000


65,000 105,000


1.500 3,400


1,713

2,519

3,526


114


st
nt


3,060

4,500

6,300


204


As both the building and equipment in the plants studied are
of a very durable type, the life of the entire plant has been esti-
mated at 20 years. The Wood-screw type of pumps have all
moving parts above water and the heavy duty diesel engines are
of a type that has been in use for 20 years in other fields. The
foundations and floors of pump houses are concrete and the build-
ings are covered with corrugated sheet metal and all but one has
steel framework.
The costs of fuel oil or electricity, lubricating oil and labor
are shown in Tables 17a, 17b and 17c. The unit costs per acre
served and per acre-foot pumped are also shown. The period
of operation is expressed in plant-days. As the oil engine plants
have two or more pumps and all or part of the units may be in
operation at a particular time, the number of days on which some
pumping was done was greater than the p'ant-days shown. The
plant-days were determined by reducing the total pump-hours
to 24-hour days and dividing the result by the number of pumps.
The Wood-screw pumps were rated with a Pitot tube and cur-
rent meter. A record of the lifts and speeds was kept. The
Experiment Station pump was rated with a current meter but
during the last two years a submerged orifice has been used and
the discharge computed from a continuous record of the head on
the orifice. The cost of fuel oil delivered at the plants has ranged
from 6.5 to 7.0 cents per gallon. The cost of lubricating oil and
gasoline includes the gasoline used in the lighting plant, in the
compressor engine and for the truck used in supervising the


Peli
Vt


Total
Fixed
Charges


0 $5,147


4,773

7,019

9,826


318


~~+,~uv i auviuv j ~uuvvv


I


,





TABLE 17A.-COSTS OF FUEL OIL, LUBRICATING OIL, AND LABOR AT PUMPING PLANTS.

Size Period of ____Costs for Year
Plant Year of Area Opera- Water Per Per
Engine Served tion Pumped Fuel Oil Lub. Oil Labor Total Acre Acre-Foot
______ __________ __ and Gas Served Pumped _
H. P. Acres Plant Acre-Feetl Dollars Dollars Dollars Dollars Dollars Dollars
Days I
Pelican Lake 1933 10iO 3,379 82.8 19,181 1,384 298 1,510 3,192 0.94 0.17
Unit No. 1 1934 160 3,379 103.4 23,764 1,710 310 1,910 3,930 1.16 0.17
1935 160 3,379 48.6 11,105 7(4 175 1,250 2,189 0.65 0.20 C
1936 160 3,379 62.8 14,174 1,089 220 1,535 2,844 0.84 0.20
1937 10 3,379 87.6 16,024 1,485 255 1,603 3,343 0.99 0.21
1938 160 3,379 24.4 4,904 398 132 788 1,318 0.39 0.27
Average 160 3,379 68.3 14,859 1.138 232 1,433 2,803 0.83 0.19


Pelican Lake 1933 160 2,853 41.5 9,858 718 159) 1,062 1,939 0.68 0.20
Unit No. 2 1934 160 2,853 61.5 14,287 1.037 235 1,315 2,587 0.91 0.18

1935 1 miO 2.853 30.6 7,488 492 117 1,143 1,752 0.61 0.23
1936 160 2,853 47.8 11,667 784 172 1,295 2,251 0.79 0.19
1937 160 2,853 65.6 15,089 1,124 205 1,313 2,642 0.93 0.18
1938 160 2,853 18.1 4,232 274 12) 678 1,072 0.38 0.25
Average 160 2,853 44.2 10,437 738 168 1,134 2,041 0.72 0.20
10,437 4 2,041 0.72 0_. 20.







TABLE 17B.-COSTS OF FUEL OIL, LUBRICATING OIL, AND LABOR AT PUMPING PLANTS.
[ Costs for Year
Size Period ofCoss fr
Plant Year of Area Opera- Water i I Per Per
Engine Served tion Pumped Fuel Oil Lub. Oil Labor Total Acre Acre-Foot
I and Gas Served Pumped
H. P. Acres Plant Acre-Feet Dollars Dollars Dollars Dollars Dollars Dollars
Days
East Pahokee 1933 360 5,798 48.2 15,607 1,070 222 971 2,263 0.39 0.14
Unit No. 1 1934 360 5,798 55.6 16,588 1,138 256 1,160 2,554 0.44 0.15
1935 360 5,798 37.4 11,210 666 172 930 1,768 0.30 0.16
1936 360 5,798 33.5 12,627 792 160 1,276 2,228 0.38 0.18
I II
1937 360 5,798 39.2 15,556 1,001 200 1,188 2,389 0.41 0.15
1938 360 5,798 23.1 8,414 503 155 833 1,491 0.26 0.18
Average 360 5,798 39.5 13,334 832 194 1,060 2,116 0.36 0.16

East Pahokee 1933 540 9,478 49.7 28,609 1,970 277 1,212 3,459 0.36 0.12
Unit No. 2 1934 540 9,478 54.6 30,271 2,086 305 1,430 3,821 0.40 0.13
1935 540 9,478 35.3 21,385 1,184 197 1,101 2,482 0.26 0.12
1936 540 9,478 41.7 26,071 1,430 286 1,459 3,175 0.33 0.12
1937 540 9,478 31.1 19,747 1,215 243 1,034 2,492 0.26 0.13
1938 540 9,478 27.6 18,796 964 201 923 2,088 0.22 0.11
Average 540 9,478 40.0 24,146 1,475 252 1,193 2,920 0.31 0.12












TABLE 17c.-COSTS OF ELECTRIC POWER AND L\BOR AT EVERGLADES EXPERIMENT STATION PUMP.


Plant Year


Everglades 1933

Exp. Station 1934

1935

1936

1937

1938

Average
I, I


Size
of
Motor


H. P.

30

30

30

30

30

30

30


Area
Served

Acres

162

162

162

180-_

180

180

171


SPeriod of


Opera-
tion

Plant
Days
72.4

55.8

51.0

60.9

42.1

11.7

49.0


Water
Pumped Electric
Power
Acre-Feet Dollars

1,670 785

1,499 780

1,349 750

1,822 8:3(

1,076 623

329 220

1,291 636


Costs for Year
Per
Lub. Oil Labor Total Acre
Served
Dollars Dollars Dollars Dollars

75 860 5.31

75 855 5.28

75 825 5.09

75 911 5.06

75 698 3.88

75 295 1.64

75 741 4.33


Per
Acre-Foot
Pumped


Dollars

0.51

0.57

0.61

0.50

0.65

0.90

0.57


'


Period of






Florida Agricultural Experiment Station


plants. No cost is shown for lubricating oil at the Experiment
Station plant as the amount used is very small and no record
is kept.
The labor costs at the four oil engine plants include the wages
of attendants and help used in cleaning screens and also that
part of the superintendent's salary chargeable to supervision of
these plants. The Experiment Station plant requires no regular
attendant, so the labor item was estimated.
Tables 18a, 18b and 18c show the total operating costs, includ-
ing fixed charges. The fixed charges are taken from Table 16.
The annual maintenance costs have been estimated at 1 percent
of the total investment in the plants. It is probable that $1 per
horsepower per year would easily cover the engine repairs. The
pumps and buildings require very little maintenance. The rec-
ords available are not sufficient to determine maintenance costs,
but 1 percent is believed to be ample. No insurance is carried
on the plants, and no taxes were included in the estimates of
pumping costs. The total costs are also shown as unit costs per
acre served, per acre-foot pumped and per acre-foot lifted one
foot.
Average costs as shown on the tables are based on the full
six-year period and hence may not be the same as the average
of the separate years. The costs per acre-foot pumped by Pelican
Lake Unit 1 is less than that of Unit 2, due to the fact that
more water is pumped by Unit 1. The costs, including fixed
charges, however, do not vary much on the acre-served basis,
being $2.52 for the one and $2.57 for the other. The levees of
Unit 1 are often subject to greater pressure than those of Unit 2,
due to high water on the outside, hence the ditches usually are
not pumped as low as those of Unit 2 and the average lift is
0.4 foot less.
The costs for East Pahokee Unit 1 are higher than those of
Unit 2. However, the tables show that the average lift is greater
for the first unit and the total depth pumped is less. Also the
cost of the plant in relation to the acreage served is greater. The
costs, including fixed charges, averaged $1.70 per acre for Unit 1
and $1.45 for Unit 2. These costs are considerably under those
shown for the Pelican Lake plants, but it should be noted that
the average depths of water pumped are considerably less, and
the cost of these plants in relation to the acreage served is lower.
The Pelican Lake plants are also less efficient than the East
Pahokee plants.






TABLE 18A.-TOTAL OPERATING COSTS OF PUMPING PLANTS, INCLUDING FIXED CHARGES.

Costs for Year
Av. Water Area Fixed Main- Oils & I----
Plant Year Static Pumped Served Charges tenance Labor Total Per Acre PerAc.Ft. PerAc.Ft.
Lift Amount Served Pumped Lifted1ft.
Feet Acre-Feet Acres Dollars Dollars Dollars Dollars Dollars Dollars Dollars
I I


3,379

3,379

3,379

3,379

3,379

3,379

3,379


2,853

2,853

2,853


Pelican Lake

Unit No. 1








Average


Pelican Lake

Unit No. 2


3,192 8,889 2.63

3,i930 9,627 2.85

2,189 7,886 2.33

2,844 8.541 2.53

3,343 9,040 2.68

1,318 7,015 2.08

2,803 8,500 2.52


19,181

23,764

11,105

14,174

16,024

4,9041

14,859


S0.46

0.41

0.71

0.60

0.56

1.43

0.57


1933

1934

1935

1936

1937

1938




1933

1934

1935

1936

1937

1938


5,147

5,147

5,147

5,147

5,147

5,147

5,147


4,773

4,773

4,773

4,773


7,222

7,870

7,035

7,534

7,925

6,355

7,324


1,9)3

2,587

1,752

2,251

2,642

1,072

2,040


9,858

14,287

7,488

11,667

15,089

4,232


Average


I


j 1








TABLE 18B.-TOTAL OPERATING COSTS OF PUMPING PLANTS, INCLUDING FIXED CHARGES.


Av.
Plant Year S atic
L;ft
Feet

East Pahokee 1933 4.6

Unit No. 1 1934 4.7

1935 4.9

1936 4.2

1937 4.5

1938 2.9

Average 4.4


East Pahokee 1933 4.7

Unit No. 2 1934 4.7

1935 4.4

1936 3.6

1937 4.5

1938 1 2.3

Average 4.1


Water Area Fixed
Pumped Served Charges

Acre-Feet Acres DoLars

15,607 5,798 7,019

16,588 5,798 7,019

11,210 5,798 7,019

12,627 5,798 7,019

15,556 5,798 7,019

8,414 5,798 7,019

13,334 5,798 7,019


28,609

30,271

21,385

26,071

19,747

18,796

24,146


9,478

9,478

9,478

9,478

9,478

9,478

9,478


9,826

9,826

9,826

9,826

9,826

9,826

9,826


Main- Ois Costs for Year
Main- Oils & _
tenance Labor Total Per Acre PerAc.Ft.I PerAc.Ft.
Amount Served Pumped I Lifted1ft.


Dollars


750

750

750

750

750

750

750


1,050

1,050

1,050

1,050

1,050

1,050


1,050


Dollars Dollars I

2,263 10,032

2,554 10,325

1,768 9,537

2,228 9,997

2,389 10,158

1,491 9,260

2,116 9,885


3,459 14,335


3,821

2,482

3,175

2,492

2,088

2,920


14,697

13,358

14,051

13,368

12,964

13,796


Dolars Dollars | Dollars

1.73 0.64 0.14

1.78 0.62 0.13

1.64 0.85 0.17

1.72 0.79 0.19

1.75 0.65 0.14

1.60 1.10 0.38

1.70 0.74 0.17













TABLE 18c.-TOTAL OPERATING COSTS OF PUMPING PLANT AT EVE(GLADES EXPERIMENT STATION, INCLUDING FIXED CHARGES.


Av. Water
Plant Year Static Pumped
Lift
Feet Acre-Feet
Everglades 1933 2.0 1,670

Exp. Station 1934 2.3 1,499

1935 2.3 1,349

1936 2.1 1,822

1937 2.2 1,076

1938 1.7 329
Average 2.1 1,291


Area Fixed
Served Charges

Acres Dollars

162 318
162 318

162 318

180- 318

180+- 318

180- 318

171 318


] Electric Costs for Year
Main- Power
tenance and Total Per Acre PerAc.Ft. PerAc.Ft.
Labor Amount Served Pumped i Lifted1ft.
Dollars Dollars Dollars Dollars Dollars Dollars

34 860 1,212 7.48 0.73 0.36

34 855 1,207 7.45 0.81 0.35

:4 825 1,177 7.26 0.87 0.38

34 911 1,263 7.02 0.69 0.33

34 698 1,050 5.84 0.98 0.45

34 295 647 3.59 1.97 1.16

34 741 1,093 6.44 0.85 0.40






Florida Agricultural Experiment Station


The fixed charges for the four oil engine plants average ap-
proximately two-thirds of the total costs of pumping. The four
plants will also average about one gallon of fuel oil per acre-foot
pumped. Most of the cultivated land of the northern Everglades
is served by pumping units similar to those of the East Pahokee
District and it is estimated that the depth pumped will average
approximately three feet per year over the area served. Of the
four plants considered, probably the costs shown for East Pa-
hokee Unit 1 will more nearly approximate the average costs
for the pumped lands. In comparison with the value of crops
raised, pumping costs are very low. In addition to the cost of
pumping, proper maintenance of ditches and levees would amount
to about $2 an acre per year.
The cost tables for the Everglades Station plant show an aver-
age annual cost for electric power and labor of $4.33 per acre
served and $0.57 per acre-foot pumped. The total costs, includ-
ing fixed charges, have averaged $6.44 per acre served, $0.85
per acre-foot pumped, and $0.40 per acre-foot lifted one foot.
The fixed charges average about one-third the total cost of opera-
tion. The rainfall in 1938 was only 41 inches and very little
pumping was done. Hence the low costs per acre served and
the high costs per acre-foot pumped for that year. Very little
pumping of the peat lands is done with electric power.
Rainfall for 1937 was 58.44 inches; depth pumped for drainage
was 6.0 feet; and evaporation is estimated at 3.5 feet. Seepage
into the pumped area, based on the above data, was approxi-
mately 4.6 feet during that year of nearly normal rainfall. This
is equivalent to an average inflow of about 500 gallons per minute
into the area pumped by the Experiment Station plant. A higher
water table without or a lower water table within an area will
increase the seepage. A comparison of the amount of pumping
with the stages of the Hillsboro Canal clearly shows this effect.
Average annual consumption of electric energy by the Experi-
ment Station plant over the six-year period has been 10,920 kilo-
watt hours and has cost $666.

EFFICIENCY TESTS ON PUMPING PLANTS
Overall efficiency tests were made at each of the oil engine
plants in 1935 and the results are shown in Table 19. The dis-
charge of the pumps was measured with a Pitot tube and the
fuel consumed in an hour's time was carefully weighed. The
static lifts are the difference in readings of the gages just out-






TABLE 19.-EFFICIENCY TESTS OF OIL ENGINE PLANTS.


Pel
I
U

U
U
I
I


Eam
I
I
I

I


Discharge Work
Plant Pump Speed per Static of Pump by
No. Minute Lift per Minute Plant
Revolutions Feet Pounds H. P.

ican Lake
Jnit No. 1 .. 1 276 4.25 227,600 29.3
Jnit No. 1 ... 2 270 4.72 201,300 28.3

Jnit No. 2 .... .... 1 272 3.22 232,100 22.6
Jnit No. 2 ..... ... 1 269 5.77 182,700 32.0
Jnit No. 2 ......... 2 290 5.95 227,600 41.1
Jnit No. 2 .... 2 275 3.27 234,300 23.2

st Pahokee
Jnit No. 1 ... 1 250 5.80 441,500 77.6
Jnit No. 1 ....... 1 227 6.15 391,500 72.9
Jnit No. 1 ...... 1 202 5.96 301,800 54.6
Jnit No. 1 ......... 1 177 5.96 240,000 43.4
Jnit No. 1 ........... 2 248 5.14 457,000 71.2


Unit No. 1 ..

Unit No. 2
Unit No. 2
Unit No. 2 ...
Unit No. 2 ...
Unit No. 2 ....


S 2

. 1
. 1
S 1
1
. 1


U nit N o. 2 ...... ..........
U nit N o. 2 ........ ......
U nit N o. 2 ..............
Unit No. 2 ...................
U nit N o. 2 ........ .......

*Value probably too high.


256
256
226
200
176


395,100

483,500
418,200
356,000
279,200
148,600

488,000
480,000
401,100
336,500
263,500


61.8

73.2
62.3
53.3
43.7
23.7


Fuel Oil Energy Overall
Used Output Efficiency
per Hour of Engine of Plant
Pounds Brake H.P. Percent


37.4 74.9 31.
34.5 69.0 33.

30.8 61.6 29.
36.4 72.9 35.
46.8 93.6 35.
31.2 62.4 30.


73.7
66.1
54.0
41.4
70.5
57.2

75.5
57.2
46.1
38.6
29.1

71.3
79.0
63.1
47.5
39.2


147.5
132.3
108.0
82.8
141.0
114.5

151.0
114.5
92.2
77.3
58.2

142.6
158.0
126.2
95.0
78.4






Florida Agricultural Experiment Station


side the screens at either end of the plant. The useful work
done by the plant, or water horsepower, is based on the pump
discharge and static lift. The energy output of engines is esti-
mated on the basis of 0.50 pounds of fuel oil per brake horse-
power. The overall efficiency is the ratio of the water horse-
power hours to the indicated horsepower hours or energy used
in the engine. The mechanical efficiency or ratio of the brake
horsepower to the indicated horsepower is estimated at 80 per-
cent. The term "plant" in Table 19 refers to a complete pump
and engine unit. Each plant has two or three such units. It is
evident that the East Pahokee plants are much more efficient
than the Pelican Lake plants. The East Pahokee pumps are
of larger size and probably more recent design. Efficiencies
based on fuel consumption and brake horsepower are necessarily
only approximate.
In October, 1937, several efficiency tests were made on the
Experiment Station pump. The power input was measured by
the watt-hour meter and the discharge with a standard weir.
The motor is connected to pump with V-belts. The motor effi-
ciency used was 88 percent and the belt efficiency 94 percent.
The static lift was measured inside the pump house. The results
were as follows:
Pump Static Pump Work Energy Efficiencies
Speed Lift Discharge Done Used Overall Pump
R.P.M. Feet Sec. Feet H. P. H. P. Percent Percent
574 4.33 17.95 8.82 26.2 34 41
442 3.94 11.72 5.24 15.1 35 42
292 3.46 5.00 1.96 7.9 25 30
The pump used in these efficiency tests was a 24-inch vertical
turbine driven by a four-speed Westinghouse induction motor
rated 30 horsepower at 1,180 revolutions per minute. A large
number of pumps of this type are used in the northern Ever-
glades, but only a few are operated by electric power. This
pump was later re-conditioned and the discharge was improved.
Capacity of Pumps.-A 12-year record of rainfall at the Ever-
glades Experiment Station shows the following average periods
between rains:
between rains: Av. Number Av. Period
Size of Rains per Yr. in Months
1.0 inch or more .- ....... .................. 17.2 0.7
1.5 inch or more ........................ 8.1 1.5
2.0 inch or more ....... ..................... 4.0 3.0
2.5 inch or more ............................. 2.3 5.2
3.0 inch or more ............................... 1.4 8.5
3.5 inch or more ............................. 1.0 12.0
4.0 inch or more -............................ 0.58 20.6
4.5 inch or more ................... ... 0.33 36.4
5.0 inch or more .............................. 0.25 48.0





Water Control in the Soils of the Everglades


The above figures indicate that excessive rains are not very
frequent. The probability of rains of two inches or more is four
in a year; of 3.5 inches or more is one in a year; and of 5 inches
or more is one in four years. Many of the heavy rains occur
during the three summer months when there is little or no
farming. Nearly half of the rains of two inches or over occurred
in that period. The damage from excessive rains is reduced to
a considerable extent by the high absorptive capacity of the peat
soils. Under usual conditions an inch of rain will raise the water
table about six inches. If the water table were two feet deep,
about four inches would be required to saturate the soil. How-
ever, as the top soil is changed by cultivation and weathering,
the seepage movement is retarded and water will remain on the
surface for a considerable period with the ditches at a low stage.
Heavy rains sometimes occur when the water table is high and
the soil wet from previous small rains. Certainly not more than
two inches should be the allowance for the decrease in pump
capacity on account of soil absorption. On this basis pumps with
a one inch capacity would handle all rains up to three inches and
the 12-year record shows only 11 rains of three inches or more
outside the summer months. With pumps of 2-inch capacity,
rains up to four inches could be cared for in this area, and only
six rains of four inches or more have occurred outside the sum-
mer. With a 3-inch pump capacity a 5-inch rain could be cared
for. The 12-year record shows three rains of five inches or more
and one of these fell in the summer period.
The Wood-screw type of pumps used in the larger drainage
units have a capacity of approximately one inch in 24 hours.
Experience indicates that this rate of discharge is sufficient
for sugarcane. During recent years nearly all the pumps in-
stalled to serve land used mainly for truck crops have had capaci-
ties varying from 1.5 to 3.0 inches. The Experiment Station
pump has served from 160 to 180 acres in recent years and the
record shows that a 2-inch discharge has been sufficient except
in the case of very exceptional rains. For rains exceeding 3.5
inches a greater rate of run-off is usually needed. Only 14 such
storms have occurred in the last 15 years and five of these have
been in the three summer months. Pumps serving truck lands
should have a capacity of two to three inches. The proper depth
of run-off will depend on the value of crops raised and also on
the area drained. A run-off of more than three inches probably
could not be justified on economic grounds. Private pumping





Florida Agricultural Experiment Station


units within a large drainage system are of value in controlling
the water table on individual farms, but the run-off provided
by such units should not greatly exceed that of the main system.

FARM DITCHES
District laterals are usually spaced a half mile apart along
section and half section lines. Farm ditches are spaced from
1,320 to 660 feet apart, the closer spacing being generally used
for truck crops. The depth of run-off which these ditches will
carry should be equal to that provided by the pumps. The ditch
banks should have a 1/2 to 1 side slope. As the land is practically
flat, a three-inch fall per mile is commonly used in calculating
ditch sizes.
The maintenance of ditches is an important problem. Water
plants such as hyacinths or moss commonly cover or fill the
channel's and Para grass grows readily on the banks. Such
growth greatly reduces the capacity of a ditch. In addition to
these, a soft soupy sludge collects in the bottoms. These growths
and deposits should be removed at regular intervals. The ditch
banks should be sodded to prevent the growth of weeds and Para
grass. The sludge in the bottoms of ditches can best be removed
with a pump type of ditch cleaner.

MOLE DRAINAGE
Subdrainage and subirrigation is accomplished by means of
moles.7 These are formed by drawing a 6-inch, bullet-nosed
cylinder through the soil between farm ditches. The depth is
commonly 30 inches and the spacing from 12 to 15 feet. The
resulting hole is about 41/2 inches in diameter.
Cleaner mole holes result if the moling is done when the water
table is below the mole depth. Spring is the best time to do
this work, for it then requires less pumping to hold a deep
water table.
If the mole work is well done, the lines will probably give
satisfactory sub-drainage for a period of from five to eight
years. At the end of the effective period the field can readily
be re-moled. The cost of such work is about 50 cents per acre.
Following a heavy rain the water table in a moled field will
drop more rapidly than in a similar field not moled. Some obser-

7 Allison, R. V. Movement of underground waters. Florida Agr. Exp.
Sta. Ann. Rpt. 1928: 117R-118R.



























Fig. 10.-Mole entering soil at side of ditch. Note vertical cut in bank
from mole to surface of the soil where the blade that precedes the mole
has entered.

vations at the Everglades Station indicate that after a rain has
saturated the soil the water table in a moled field will drop a foot
in about one third the time required for a field without moles.
In a pumped area subject to pressure, due to higher water out-

Fig. 11.-Mo'ing machine in operation. The mole (as shown in Fig. 10)
is being drawn through the soil at the bottom of a heavy blade carried at
the end of the eye-beam and directly beneath the man on the machine at
the right.






Florida Agricultural Experiment Station


side the dikes, the water table in the fields will usually stand
substantially higher than that in the ditches. In such cases the
mole drains will tend to level out the water table and reduce
this difference.
As far as possible it is best to install the mole lines before
digging the farm ditches, for in this case the moles will have
outlets in ditches at either end, whereas if the work is done later
each line will have a dead end. Also the depth should not be
less than 30 inches, for experience has shown that shallower
lines may be closed up by the weight of farm machines.

WATER TABLE STUDIES
THE WELL LINES
In the spring of 1932 a number of well lines were established
to record the rise and fall of the ground water elevations in cer-
tain areas near Lake Okeechobee. For several years prior to
1932 the Everglades Station made weekly readings along several
lines on the station property. Two of these lines extended in a
southwesterly direction from the Hillsboro Canal and across
several farm ditches located 240 feet apart.
The data indicated that with a high level in the Hillsboro
Canal the seepage gradient diminished rapidly with distance
from the canal. On irrigation tests the data also showed that
the plot water tables were substantially below the high level in
the ditches. Line "G," mentioned in this report, was one of
these old lines and the subsequent data were consistent with the
earlier measurements. A third line extended from the Hillsboro
Canal across virgin land owned by the Experiment Station. This
line was relocated in 1932 and designated as Line "A" and read-
ings were continued for several years.
The location of the lines as established in 1932 are shown on
Figure 1. A chart for each line shows the fluctuations of the
water table in a typical well over a period of several years.
The rainfall, lake or canal levels and other data affecting the
ground water levels are also shown. A profile for each of the
lines shows typical ground water curves, the depth of peat, and
the distance between wells. Charts and profiles have been pre-
pared for 12 lines designated as A, B, C, D, E, G, M, O, Q-R,
S, T, and U. A map showing ties to section corners and a short
discussion of the water table variations has been prepared for
each of the lines.






Water Control in the Soils of the Everglades


In this report, data for only a few of the more important lines
are presented. Charts and profiles for the remaining lines may
be secured from the Soil Conservation Service, Washington, D. C.
Well Line D.-Line D (Fig. 1) begins at the old levee on the
south side of Lake Okechobee and extends south across the east
portion of Sections 5 and 8; Township 44, Range 36, to the
Florida East Coast Railroad. The location is about a quarter
mile west of the east line of these sections, and is in the South
Shore Drainage District. A road ditch along the north side of
Section 8 provided some drainage for the land. The drainage


Fig. 12.-Hydrographs of Wells 8 and 27, Line D, and Lake Okeechobee;
rainfall near Line D.










I JANUARY |FEBRUARY MARCH
1935


APRIL MAY JUNE JANUARY FEBRUARY MARCH PRI MAY JUNE
1936
,----- -- i


Fig. 13.-Hydrographs of Wells 8 and 27, Line D, and Lake Okeechobee; rainfall near Line D.






Water Control in the Soils of the Everglades


district had no permanent pump installations until the spring
of 1938, when a 35,000-gallon pump was installed. Land south
of the railroad line is in the South Florida Conservancy District,
which is drained by pumps. The water table along Line D is
probably lowered somewhat by seepage into this pumped land
during the summer and fall months.
The soil is Okeechobee (custard apple) muck underlaid with
limestone at an average depth of 7.5 feet. During the period
of the record the land was used for truck crops. The drainage
was not very good until pumps were installed in 1938.
Well records on this line began in May, 1932, and readings
were made about once a week until July, 1934, when automatic
gages were installed at Wells 8 and 27. Figures 12 and 13
show the variations in water tables at these wells and also the
stages of Lake Okeechobee. The rainfall shown is the average
of that at South Bay and Lake Harbor. Figure 15 shows a
profile along line D and the depth of soil.
The lowest stages in both well's occurred in May, 1932, when
the lake was at a record low stage. The low stages were pre-
ceded by nearly a year of very low lake levels and by more than
a year of subnormal rainfall.
Well 8 is located 1,000 feet south of the old Everglades Dis-
trict levee and 1,700 feet south of the new Government levee.
The stages in this we:l are strongly affected by the lake level.
Near the end of the dry season in the latter part of May or early
June the well water has averaged about 0.7 feet below the lake
and the extreme differences have ranged from 0.5 to 1.5 feet.
The corresponding lake elevations have varied from 12.5 to 15.8
feet. The extreme differences between lake and well stages in
January averaged 0.6 feet and ranged from 0.4 to 1.0 feet. The
low lake stage for January, 1933, was 14.5 and for January of
the years 1934 to 1938 was approximately 16 feet.
Well 27 is located 5,000 feet south of Well 8 and 6,700 feet
from the new levee. The extreme low stages in the latter part
of May or early June averaged 2.3 feet below the lake and varied
from 1.0 to 3.2 feet below. The extreme low stages for January
averaged 2.2 feet below the lake and varied from 1.6 to 2.6 feet
below.
Wells 8 and 27 are almost one mile apart. The extreme low
stages in January for the years 1933 to 1938 show an average
difference of 1.5 feet and those for May or June a difference of
1.8 feet. This greater slope at the end of the dry season is






Florida Agricultural Experiment Station


doubtless due to the fact that evaporation and seepage have
lowered the water table in land south of the cultivated area.
On account of variation in rainfall and other conditions, it is
difficult to determine the effect of changes in lake stage on the
water table in the outer lands. Although a comparison of lake
stages with the stages in Well 27 do not show a consistent differ-
ence, it is evident that a substantial change in lake elevation
has some effect on this well. However, the effect appears to be
small and it seems probable that an increase of two to three feet
in the normal lake height would cause no substantial increase
on the water table several miles out.
The new levee was completed across the end of Line D in the
summer of 1935. Beneath the levee are two trenches which
were excavated to rock and then refilled with marl and shell.
The purpose of the one near the inner toe is to prevent fires
from reaching the organic materials beneath the fill and that
of the other is to decrease seepage. A comparison of the stages
in Well 8, before and after the levee was completed, indicate
that the construction of the levee has had little effect on the
water table near this well.
Well Line E.-Line E begins at the edge of Lake Okeechobee,
about 11/4 miles northeast of Pahokee, in Section 8, Township
42, Range 37, and extends in a southeasterly direction through
the Boe farm to the Florida East Coast Railroad. The line
crosses a sand ridge at a point 610 feet from the levee. Well 6,
at the east toe of the ridge, is 710 feet from the levee and Well
10 is 1,440 feet from the levee. East of the railroad is a low
area once covered by Pelican Lake. This is now drained by
pumps and as a result the water table along this line is lowered
by seepage into this low area. The soil east of the sandy ridge
is deep Okeechobee "custard apple" muck and is used for truck
crops.
Readings along this line began in May, 1932. In July, 1934,
an automatic water level recorder was installed at Well 10. The
principal purpose of the line was to show the effect of lake stages
on the water table in the adjacent land. Figure 14 shows the
water levels in Wells 6 and 10, lake stages, and rainfall for the
first half of the years 1935 to 1938. This period is used because
it includes the dry part of the year when the rainfall and water
tables are at minimum and the effect of lake stakes are most
apparent. Figure 15 shows a profile along this line.
In January, with a normal lake elevation of about 16 feet, the








JANUARY FEBRUARY MARCH I APRIL MAY JUNE ) ) JANUARY I FEBRUARY I MARCH I APRIL MAY JUNE

1935 1936
SA pp o ground surface near well no 10
Lake Okeechoee--

Well 6

4 -'-- ,- -WelllO I'












010 300 030 779 064 763 259 4b0 2 76 033 544 I247

1937 1938


6 n








3 f 2 343..S
3 -

I. I 24 34


Fig. 14.-Hydrographs of Wells 6 and 10, Line E, and Lake Okeechobee; rainfall at Azucar.








































Fig. 15.-Profiles of Lines D and E.





Water Control in the Soils of the Everglades


lowest readings at Well 6 have averaged 1.6 feet below the lake
and those at Well 10 have averaged 2.6 feet below lake level.
The difference of one foot between these wells is equivalent to
a slope of 7.2 feet per mile in the seepage gradient. The extreme
low readings in these wells occur near the end of the dry season
in May or early June. With a lake elevation of about 15, the
low readings in this period have averaged 2.4 feet below the lake
at Well 6 and 3.7 feet at Well 10. The difference of 1.3 feet
between these wells is equivalent to a slope of 9.4 feet per mile
in the seepage gradient. This increase of slope between January
and May or June is due to a lowering of the water table in the
adjacent lands by seepage and evaporation.
The new levee across the head of Line E was closed in October,
1935. Beneath the fill are two trenches which were dug to rock
and refilled with marl and shell. It is probable that very little
seepage can penetrate these fills. A study of the well readings
along Line E indicates that the new levee has had no substantial
effect on the water table in adjacent lands. This and other obser-
vations appear to show that the seepage movement between the
lake and adjacent lands takes place through the porous limestone
and sand beneath the peat rather than directly through the peat
deposit.
On account of the variation in rainfall and amount of pump-
ing, it is difficult to determine the effect of changes in lake stage
on the water table in this area. A substantial change in lake
stage will raise the water table at Well 6, but the raise is con-
siderably less at Well 10. The effect certainly decreases with
distance from the lake. A change of several feet from normal
lake level would probably have no substantial effect on the water
table a few miles from the levee. As previously noted, the water
table at Line E is affected by the low land in the old Pelican Lake
area. The water table along Line D is the more typical of the
general condition around the lake. The lake level is regulated
as nearly as possible between 14 and 17 feet. The average stage
of 16 feet is probably the most favorable height for present agri-
cultural conditions. However, as the farm lands continue to sub-
side a lower level may become desirable.
As the water table in the peat land near Lake Okeechobee is
affected by rainfall, pumping, lake and canal stages, it is diffi-
cult to draw general conclusions from a study of fluctuations
along well lines. The study, however, shows that the water table
in a field is usually not the same as that in the ditches. Follow-






Florida Agricultural Experiment Station


ing a rain the profile of the water table between ditches shows
a very flat curve with a rather sharp drop to ditch levels near
the ends. This curve will slowly flatten as pumping continues
and during dry spells with no pumping may reach a point about
one-half foot below ditch levels. Fields adjacent to a levee with
high water stage outside may have a water table close to the
surface when the interior drainage ditches are at a low level.
This pressure causes a seepage flow through the porous rock
or sand and thence upward into the fields. If the water table
outside a dike were held a foot above the land within it is prob-
able that a strip about 100 yards wide would be too wet for satis-
factory farming even though the ditches were held at a low level
by pumping. A small ditch along the toe of a dike will substan-
tially depress the seepage gradient.

WATER TABLE PLOTS
To determine the effect of water table depth on crop yields
eight water table plots were established at the Everglades Sta-
tion. The plots are approximately 100 by 240 feet in gross size,
and are surrounded by ditches on three sides. Mole drains 15
feet apart extend across each plot and connect the side ditches.
Two 1,000-gallon pumps with electric motors maintain the de-
sired water tables at near-constant levels. Two of the plots are
equipped with overhead spray lines.
One-third of each plot has been planted to sugarcane, one-third
is used for truck crops, and the other third is used for grass or
forage crops. The water tables in the several plots varied from
approximately one to three feet. During the years 1937 and
1938 water table depths of 1.0, 1.5, 2.0, 2.5, and 3.0 feet were
held as nearly as possible in the particular plots.
For about 18 months before operation the water table was
approximately the same in the whole area and during this period
corn was grown on all plots to determine their relative produc-
tivity under conditions of equal water tables. The maintenance
of definite water tables at different levels was begun in Novem-
ber, 1935.
After a few more crop years a complete report will be prepared
covering the crops as well as the soil conservation phases of these
water table experiments. The results so far obtained indicate
that a 1.5 to 2.0-foot water table is best for truck crops; that
grasses do well on a table held at from 1.0 to 2.0 feet; that some






Water Control in the Soils of the Everglades


varieties of sugarcane produce good yields on a 1.0 to 1.5-foot
table while other varieties do better on a deeper table.
The canes producing best on a high water table are of partic-
ular value from a soil conservation standpoint, for the higher
the water table the less is the surface subsidence of the land.

SUMMARY

An outstanding need of the Everglades is a comprehensive
plan of water conservation whereby the water now wasted could
be used to maintain a higher water table in the idle lands and
thus decrease the losses from subsidence and fires. This should
also provide for a definite system of outlet canals for all land of
agricultural value so that an orderly development could be
achieved. Under present conditions expansion is taking place
without such a plan, thus complicating the problem of providing
a consistent scheme for the whole area.

SOILS
The major portion of the peat lands of the Everglades consists
of the partially decayed residue of sawgrass deposited over a
period of thousands of years. A field sample of this soil when
oven-dried loses about three-fourths of its weight. The ash or
mineral content is about 10 percent of the dry weight. After
drainage and cultivation for a period of 10 to 15 years the dry
weight of the top 18 inches of soil about doubles. The Okee-
chobee (custard apple) or plastic muck on the east and south
sides of Lake Okeechobee has a mineral content of 35 to 70
percent of the dry weight. Between the "Everglades" peat and
the plastic muck is an area of Okeelanta peaty muck (willow
and elder) land with a mineral content intermediate between the
peat and the muck.
SUBSIDENCE
Subsidence of peat soils is due to natural oxidation, fires,
shrinkage and compaction caused by lowering the water table
and cultivation. The loss in elevation of the drained deep peat
lands in the northern Everglades has been approximately five
feet since drainage. About 1112 feet of this loss is accounted
for by the increase of dry weight in the upper portion of the
soil. The present rate of loss is approximately one inch per
year. The loss is about proportional to the average depth of






Florida Agricultural Experiment Station


water table. Okeechobee (custard apple) muck subsides some-
what slower than sawgrass land.

SEEPAGE
The rate of seepage through virgin sawgrass peat soil is very
slow in a horizontal direction. However, after cultivation and
weathering, the vertical movement through the top portion of
the soil also becomes very slow due to changes in the soil struc-
ture. There appears to be a considerable movement of the seep-
age water through the porous rock and sand beneath the peat.
Pumping records show that a large part of the water pumped
enters the drained area through seepage.

RAINFALL, EVAPORATION AND TEMPERATURE
In the northern Everglades the average rainfall for the four-
month period from June to September is approximately 60 per-
cent of the mean annual amount. A 141/2-year record at the
Everglades Experiment Station shows an average annual rainfall
of 57.3 inches. The greatest intensity for a one-hour period
was 3.25 inches.
Estimates based on tank experiments with sugarcane indicate
an annual evaporation and transpiration from cane fields of 42
to 45 inches per year. Similar experiments with sawgrass
showed an annual loss of 84 inches from a dense stand of grass
and 68 inches after the stand had deteriorated to some extent.
As the average stand over the sawgrass areas of the Everglades
is less dense than that in the experimental tanks, it is estimated
that the loss from such areas would approximate 60 inches per
year.
The lowest temperature recorded in the Everglades was 9' F.
at Shawano on virgin sawgrass land. A comparison of low tem-
perature records indicates that minimum readings will be about
4 degrees higher on cultivated land than on nearby virgin land
at temperatures below 38 F.

WATER CONTROL BY PUMPING
Pumps are essential for the proper control of water in the
northern Everglades. The sub-drainage districts of this area
have a total rated pumping capacity of 4,200 second-feet. In
addition to these sub-district pumps there are a large number
of small pumps serving private farms. The area served by






Water Control in the Soils of the Everglades


pumps in the northern Everglades is approximately 100,000
acres.
Most of the sub-districts are served by large pumps of the
Wood-screw type with a capacity of approximately one inch over
the area served. Records have been kept for four pumping plants
of this type over a period of six years. The average static lifts
of these plants varied from 3.5 feet to 4.4 feet. The fuel oil con-
sumption was approximately one gallon per acre-foot of water
pumped. The mean annual depth pumped over the six-year
period varied from 2.3 feet for one of the larger units to 4.4
feet for one of the smaller units and the total cost of pumping,
including fixed charges, varied from 81.45 to S2.57 per acre
served. The fixed charges amounted to about two-thirds of the
total cost of pumping.
The annual cost of electric power at the Everglades Experi-
ment Station plant, over a period of six years, averaged 83.90
per acre served and 6.1 cents per k.w.h. used, and the average
period of plant operation was 49 days per year. The amount of
pumping depends very much on the stage of the Hillsboro Canal.
as this affects the rate of seepage into the pumped area.
A pumping capacity of two to three inches is recommended
for areas of moderate size used to grow truck crops. The proper
depth will depend on the kind and value of crops grown and also
on the size of area drained.

DITCHES AND SUB-DRAINAGE
Collection ditches should have a total capacity equal to that
of the pumping plant, and should be kept clean of hyacinths,
moss and grasses, which greatly reduce the channel capacity.
Mole lines, usually spaced 12 to 15 feet apart and 30 inches
deep, provide an inexpensive sub-drainage system and increase
the rate of drop of the water table after heavy rains.

WATER TABLE STUDIES
Records from well lines near Lake Okeechobee indicate that
the new lake levee has had little or no effect on the seepage
gradient from the lake to adjacent lands. A continuous water
table record has been kept at a well 6,700 feet south of the new
levee near Bean City. During the dry periods from January to
June with the lake at a 15 to 16-foot stage the water table at
this well was approximately 2.3 feet below the lake. A sub-
stantial change in lake level appeared to have a small effect at






74 Florida Agricultural Experiment Station

this point, but at a distance of several miles from the lake it is
believed the lake effect would be negligible.
Water table studies at the Everglades Experiment Station in-
dicate that truck crops give best results when the depth to water
is 1.5 to 2.0 feet, while grasses and some varieties of sugarcane
do well when the water in the soil is maintained at an appreciably
higher level. Such considerations, under practical conditions in
the field, shall have to take into account such features as trans-
portation in the field, plant anchorage in relation to wind damage,
and many others.




University of Florida Home Page
© 2004 - 2010 University of Florida George A. Smathers Libraries.
All rights reserved.

Acceptable Use, Copyright, and Disclaimer Statement
Last updated October 10, 2010 - - mvs