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Utah Agricultural College

EXPERIMENT STATION

Bulletin No. 1 44






ttl







Water Table Variations

Causes and Effects



BY

A. B. BALLANTYNE



Logan, Utah, May, 1916.



Lehi Sun Print
Lehi. Utah.



UTAH AGRICULTURAL EXPERIMENT
STATION



BOARD OF TRUSTEES.

LORENZO N. STOHL Brigham

THOMAS SMART Logan

JOHN Q. ADAMS Logan

ELIZABETH C. McCUNE Salt Lake City

J. W. N. WHITECOTTON Provo

JOHN DERN Salt Lake City

JOHN C. SHARP Salt Lake City

ANGUS T. WRIGHT Ogden

J. M. PETERSON Richfield

HAZEL L. 'DUN FORD Salt Lake City

GEO. T. ODELL Salt Lake City

JOSEPH QUINNEY, JR. Logan

DAVID MATTSON, Secretary of State, (Ex-officio) Salt Lake City

OFFICERS OF THE BOARD.

LORENZO N. STOHL _ President

ELIZABETH C. McCUNE Vice-President

JOHN L. COBURN Secretary

HYRUM E. CROCKETT Treasurer

EXPERIMENT STATION STAFF.
J. A. WIDTSOE, Ph. D., President of the College.

E. D. BALL, Ph. D Director

WM. PETERSON, B. S. Consulting Geologist

H. J. FREDERICK, D. V. M Veterinarian

E. G. TITUS, Sc. D Entomologist

L. D. BATCH ELOR, Ph. D Horticulturist

F. S. HARRIS, Ph. D Agronomist

F. L. WEST, Ph. D Meteorologist

J. E. GREAVES, Ph. D Bacteriologist

W. E. CARROL, Ph. D Animal Husbandman

BYRON ALDER, B. S Poultryman

G. R. HILL, JR., Ph. D Plant Pathologist

W. H. HOMER, JR., M. S Acting Horticulturist

C. T. HIRST, M. S. Assistant Chemist

ARCHIE EGBERT, D. V. M. B. S. Assistant Poultryman

H. J. MAUGHAN, B. S Assistant Agronomist

B. L. RICHARDS, B. S Assistant Plant Pathologist

GEORGE STEWART, B. S Assistant Agronomist

GEORGE B. CAINE, M. A Assistant Animal Husbandman

LESLIE A. SMITH, B. S Assistant Bacteriologist

WM. GOODSPEED, B. S Assistant Horticulturist

AARON BRACKEN, B. S Assistant Agronomist

H. R. HAGAN, B. S Assistant Entomologist

N. I. BUTT, B. S Assistant Agronomist

E. T. CARTER, B. S Assistant Chemist and Bacteriologist

VIOLET GREENHALGH, B. S Clerk and Librarian

O. BLANCHE CONDIT, B. A Clerk

IN CHARGE OF CO-OPERATIVE INVESTIGATIONS WITH U. S.
DEPARTMENT OF AGRICULTURE.

L. M. WINSOR, B. S _ Irrigation Engineer

J. W. JONES, B. S ....Assistant Agronomist



WATER TABLE VARIATIONS.

BY A. B. BALLANTYNE.

INTRODUCTION.

As stated in Bulletin No. 143 the matter contained there
and in the following pages grew out of seepage conditions on
the Southern Utah Experiment Farm, which necessitated the
removal of a five acre vineyard in 1908 and of a seven acre
orchard in 1910. The general soil conditions were there briefly
indicated and the extent and physical conditions of the root
systems discussed. In this bulletin is shown the effect of rain-
fall and irrigation water on the soil in relation especially to its
free water content at various seasons and how this varies. A
brief discussion of the fluctuations shown and of their effect on
the soil and vegetation is also included; this, with the conditions
of the farm especially in mind.

A history of the seepage conditions on the farm if carefully
written would be similar, with slight modifications, to that of
many other sections in the int6rmountain region, with this one
factor well in mind that the soil under discussion is decidedly
sandy, especially below the first foot. 1 Such a soil would
necessarily permit the very free movement of water within it,
if it were not hindered by the presence of too great a quantity of
alkaline salts.

For this reason, more or less alkaline soils of different
physical texture such as the clays, loams and silts, might not,
under excessive irrigation, reveal as great fluctuations of the
water table as the ones shown. The seepage conditions might
be manifest by only a boggy condition of the soil, and the presence
of quantities of free water might be detected only by the well
being kept open for some time.

On more porous soils, as the gravels, if the drainage were
good less marked fluctuations would occur; but if this drainage
were not free, then the fluctuations might be even more marked
than those illustrated here.

The Wells: As suggested previously, these borings down to
water were made in the fall of 1910, the main purpose being to

1 For a discussion of the Physical and Chemical characteristics of
this soil see Utah Station Bulletin No. 121.



4 BULLETIN NO. 144

determine the nature of the movement of the free water or the
water table level within the soil. It was of course known that
water applied on the surface would induce a change in the level
of the free water in the soil, but it was desirable to know just
how much and why it varied.

It may be well to state that in 1910 the line of demarkation
between the seeped and normal portions of the farm was
practically coincident with the drive which separated the upper
and lower halves of the farm.

Six wells were originally bored, and as nearly as possible
each was located so as to represent the different areas on the
farm and the different stages in the process of becoming seeped.

Well No. 6 was bored in the old vineyard and was intended
to represent the highest and best drained land on the farm. Well
No. 1 was also on the upper part of the farm but in a small
slightly swale-like depression and the surface soil had always
shown considerable alkali. The surface soil here is clay loam,
which with the alkali has made the rate of growth of the trees
in the vicinity less than that of those in the rest of the orchard.
It was expected that if seepage effect should appear in the upper
haJf of the farm that this would be one -of the first places, and
this proved to be true, as the entire southcentral portion of the
Elberta peach orchard later sickened and died.

Wells Nos. 2 and 3 were in an old lucern patch on the south-
west portion of the farm. The lucern all through this patch was
short and stunted and at no time through the season made more
than half a normal crop. 1 To the north of well No. 3 half way
between that and No. 4 was a small area in which the alfalfa had
died out. Well No. 4 was on the edge of the alfalfa field in an
area that had originally been planted to orchard and vineyard,
but which had been removed on account of seepage. 2 The
alfalfa around well No. 4 grew quite well for a few years but
later had mostly died out and all of the orchard in the region

1. On this area the third crop of lucern in 1911 was cut and left
on the ground and that and the fourth crop were plowed under and the
whole patch was seeded to fall oats. The lucern came up with the
oats the next spring, and after the grain ripened the lucern grew up and
was again plowed under, the land seeded to oats and the process
repeated; hence the irrigations after the oats were removed.

2 This area was seeded to oats and alfalfa in the spring of 1911
and a fair stand of alfalfa resulted which remained through 1914.



WATER TABLE VARIATIONS 5

between wells Nos. 4 and 5 had been destroyed, well No. 5
representing the central portion of this area.

Well No. 7 was bored later than the remainder of the wells,
as it was observed that a few trees in the apple orchard were
showing the effect of seepage, so this well was put down to
ascertain the depth to water in this section. At the time the well
was bored the water stood 8 feet 6 inches from the surface. A
year before this it was 10 feet from the surface only a very short
distance to the northeast of this location.



We.ll* 5



Apricot-

_____

Well *4



i 4 ..,

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We.ll-6



02=1



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Wn3



Wll*2



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Method of Measurement: To insure uniformity of measure-
ment, a wooden plate was placed at the edge of the hole even
with the surface. A light, 12-foot wooden rule, graduated to
tenths of inches, was used in measuring the depth of the water
from the surface. This was inserted in the hole and lowered
until the tip rested on the mud, the distance noted and if the tip



6 BULLETIN NO. 144

was wet, the amount of it was subtracted from the first reading
and the result recorded. If the well was filled in as was usually
the case, it was cleaned with the auger and an hour or so later
the depth was measured. The measurements were taken to
tenths of inches. At first semi-weekly measurements were
planned, but later it was found that rainstorms and irrigations
usually altered the level of the water table so the measurements
were, if possible, taken before and after irrigations.

From October, 1910, to January, 1911, the measurements
were made by Joseph T. Atkin who had no soil auger so that the
depth of the water could not usually be determined. However,
after January 12, 1911, only one measurement was missed that
of Well No. 4 July 12, 1913, and for this one there is a break in
the graph ; otherwise the rest of the measurements are com-
plete and accurate from September 16, 1910, to September 16,
1913. The semi-monthly measurements for the following year
used in the tables are also complete.

In the following charts, is given a graphical representation
of the vertical movement of the water table in the respective
wells. The heavy vertical lines below the body of the chart in
the section marked "Irrigations" represent irrigations of the
ground immediately around the respective wells. The irregular
heavy vertical lines below represent the precipitation in inches.

The charts or graphs represent a total of 915 measurements
extending from September 16, 1910, to September 16, 1913. la
addition each well was measured semi-monthly from the latter
date to September 16, 1914, making a total of 1,111 measurements
on which this discussion is based.

Discussion.

In general the measurements show that an intimate relation-
ship exists between the water table level and the conditions of
drainage, precipitation, surface evaporation, and the amount of
water applied at, and the frequency of irrigations.

Drainage: On the higher bench lands with deep gravelly
subsoils, the other causes will operate slightly if at all when
the country drainage is unimpeded. On low bottom lands, how-
ever, these agencies will have greater effect, the rate of evapor-
ation and amount of rainfall governing to an appreciable extent
the level of the water table.




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WELL N,. I



1912



Irrigations



i, I



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Precipitalhn, _[ . ,j .. .L. i .IT I .IJI . J




Plates 1, 2 and 3.



8 BULLETIN NO. 144

A study of the movement of the water in all of the wells
during the winter and spring when irrigating water was not
applied to any extent shows that the level without exception
persistently lowered as the season progressed up to the time when
the first spring irrigation w T as applied.

This indicates that the amount of water lost by evaporation
(and the little used by the vegetation) and that carried away by
the natural drainage was greater than the amount applied
mainly in the form of rain. Thus, if no irrigating water was
applied or none escaped into the natural drainage, the water
level would soon sink to the point at which it would be main-
tained by the seepage from the canal. It may be well to add
that the main canal extends along the eastern side of the farm
and water runs continually through it, being turned out only
for about two weeks in late March or early April to allow the
annual cleaning. Hence the water which fills the soil above the
level which the seepage from the canal would maintain, comes
from that received on the surface by irrigation or precipitation.

Effect of Rainfall: The extent to which rainfall will in-
fluence the movement of the water table apparently depends upon
the amount of rain falling within a given time, the condition of
the soil, and the distance from the surface of the soil to the water
level. If the free water is a considerable distance below the
surface and the rainfall moderate the section of soil between will
retain. the bulk of the water received and will permit but a small
amount to join the country drainage, thus slightly affecting the
water level. Conversely, a moderate or great amount of rain-
fall will readily saturate a much thinner section of soil, and the
greater quantities of water escaping into the country drainage
will cause an appreciable rise in the water level, where it is but a
short distance below the surface. That is, the farther from the
surface the free water is the less will it be affected by given
amounts of rainfall.

For instance Wells Nos. 4 and 5 for July of 1912. On the
15th of this month Well No. 4 showed water at 4 feet, 10 inches ;
rains between then and July 26 caused a rise of 5 inches, and in
W T ell No. 5 caused $ rise of 10.3 inches. Well No. 7 showed a
rise of an even foot, while Well No. 1* showed a rise of only 2.5
inches. 1

1 Wells Nos 2, 3 and 6 also slaved rises, but the land around was
irrigated in the interval so these are not quoted.



U ..I . I.I .I...I. . .1.. \P^cipitation {




Senri Oct. Nov. I Dec. I Uan. Feb. I Mar. , Apr. May Uune\ Uuly I

prill Tii MI: r i: Tf i i T i "r f i ri j i i r i I i i ri i I i i rri I rn n I i i r i|



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4



WELLNo3\



\WELLNo2\



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1912



Irrigations j



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Plates 4, 5 and 6.



10 BULLETIN NO. 144

It will be seen that the water levels in Nos. 5 and 7 for this
period (July 15) were respectively over one ancl two feet lower
than in Well No. 4, while the rise in each was over twice as great
(July 26). This additional rise was probably caused by the
irrigation of a soja bean crop which was about twenty rods
directly east of Well No. 7 and on higher ground so that the
drainage from that area probably affected the water level in both
Nos. 7 and 5, which were in the direct line of drainage. Besides,
Well No. 7 was in a cultivated area, while Nos. 4 and 5 were in
an alfalfa field, the alfalfa growing much ranker around Well
No. 4 so that the percentage of soil moisture in its vicinity was
probably much less than in that of either of the others. However,
the mean rise by July 26 of the level in the three showing the
water level to be nearer the surface July 15, was over one foot
two inches as against 2.5 inches in the wall where the water level
was from one foot five inches to three feet seven inches lower
than in the others.

While the amount of precipitation is not great 1 being 8.03
inches yet the winter stormy spells have a distinct effect upon
the movement of the water table especially shown on the graphs
as upward bulges from the line or ideal curve which would
represent the gradual unimpeded lowering of the free water in
the soil due to its removal by natural drainage alone. In the
graphs of all of the wells for the period from the latter part of
February to late in Marh of!912, such upward bulges occur, and
these can not well be attributed to other causes. The graphs of
Wells Nos. 4 and 5 for 1911 also show this upward bulge through
January, February, March and part of April ; and this is true of
practically all of the wells for this period- The wells Nos. 2, 3,
4 and 5, where the water was nearer the surface, show the greater
tendency in this respect. The same condition would probably
have been. shown more distinctly in the spring of 1913 had sick-
ness not prevented the taking of measurements.

Evaporation: In a reverse manner the unimpeded evapor-
ation from the surface would help to lower the level of the water
table faster than the natural drainage alone would do it. The
degree to which it would help would of course depend upon the
state of the surface soil, the amount of vegetation present,

1 The precipitation occurs mainly in two periods the three winter
months and through July and August.



l 1.. . I.I .I... .1 . .. Precipitation






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Plates 7, S and 9.



12 BULLETIN NO. 144

meteriological conditions and the distance of the water table
from the surface. Marked specific instances are not present in
enough cases to warrant attention being directed to them, mainly
because during the periods when rainfall was not abundant
and thus evaporation high irrigation water was applied to the
crops then growing upon the land. Besides, to gain an accurate
idea of this relation, daily measurements would probably have
to be taken and an accurate record made of meterological con-
ditions during the period.

Effect of Irrigations.

Size of Stream: The size of the stream used on the Southern
Utah Experiment Farm varied, ranging from about two to three
second-feet in the stream that watered the ground around Wells
Nos. 1, 6 and 7, and from three and one-half to probably five and
one-half second-feet in the stream that watered the soil around
the rest of the wells. These are estimates as there was no weir
on the place and only in two or three places was it possible to
secure as much as a six or eight inch drop for one. It is realized
that had measured quantities of water been applied the results
obtained would have been more valuable.

Method of Applying Water: In all of the irrigations on the
Farm the furrow method was used. In the orchard from four to
seven were made between the tree rows (which were 16 feet apart) ;
in the vineyards two or three were made between the rows (7 feet
apart) ; and in the alfalfa and grain a marker left the furrows
twenty to twenty-six inches apart. Some flooding nearly always
occured near the head ditches in the low places, and to some extent
at the bottom of the patches.

In 1910 and 1911 the general method and length of time
used in applying the irrigations were those that had been used
on the Farm for a number of years. In 1912 and 1913 an attempt
was made to reduce the number of irrigations and the amount of
each on all of the land except that in which "Wells Nos. 2 and 3
were located. On this (Plat "B") the water was not applied
oftener than necessary, but the length of time it was allowed to
run was not altered, except in two instances June 21, 1911, and
July 17, 1912 when it was watered in six hours, or in about half
the usual time.

Influence of Water : As noted before the graphs of the well



WATER TABLE VARIATIONS 13

measurements show that as soon as the fall irrigations ceased, the
water level began to lower and continued to do so until the time of
the first spring irrigation. 1

TABLE No. I MEAN SEASONAL VARIATION SHOWN BY 254
MEASUREMENTS FROM ALL WELLS.





Ft. In.


Ft. In.


Ft. In.


Ft. In.


Ft. In.




1910-11


1911-12


1912-13


1913-14


Mean


November


8 3.6


7 0.1


6 5.1


8 3.7


7 6.1


March


9 2.5


8 0.4


7 3.4


8 10.7


8 4.2


July


6 7.0


6 3.5


6 9.5


7 2.6


6 8.6



This is brought out very clearly by a study of Table No. 1
which shows the mean monthly depth of the water table for four
years to have been at 7 feet 6.1 inches for the month of November,
or at the end of the summer and fall irrigation season. From
then until March it sank to a mean depth of 8 feet 4.2 inches,
revealing a mean lowering of 10.1 inches. This does not represent,
however, the lowest points reached by tne water table as Table
No. II illustrates. This represents the measurements taken just
before the spring irrigation, when the level was lowest.

TABLE No. II LOWEST LEVELS RECORDED.



Date




Year


No. 1
Pt. In.


No. 2
Ft. In,


No. 2
Ft. In.


No. 4
Ft. In.


No. 5
Ft. In.


No. 6
Ft. In.


No. 7
Ft. In.


Mean
Ft. In.


Apr.


17


1911


11 6.0


9


11.


8 2.2


8 3.5


8 4.


11 3.7




9 7.1


Apr.


17


1912


10 5.6


8


6.3


7 4.


7 4.


7 2.7


10 6.


9 7.0


8 8.5


Apr.


14


1913


8 9.0


7


6.0


6 3.


6 2.3


6 6.


9 1.7


8 4.0


7 6.3


Mar.


2


1914


11 0.7


10


5.0


8 2.7


6 7.5


8 7.5


10 4.5


8 11.


9 2.1



The mean lowest level reached in the spring through four
years is thus 8 feet, 10 inches, or nearly six inches below the lowest
mean monthly level.

Effect of First Spring Irrigation: Immediately after the
first spring irrigation usually given after the middle of April
a rise in the water table is nearly always noted, as will be seen

1 This was usually given between April 15 and April 25, and while
it may seem early, yet it is about a month later than is common in the
ne : ghborhood. We should also remember in connection with this, the
bright, warm winter enjoyed by this locality and that four inches of
rain is all of the moisture the soil received after the fall irrigation, in late
October or November, to supply the loss by evaporation and the amount
used by the plant before active growth begins in early March.



14 BULLETIN NO. 144

by consulting all of the graphs. The amount of the rise is not
constant for the wells in any season nor does any one well show
an approximately uniform annual variation from the effects of
the first irrigation. As shown by Table No. I the rise continues
with variations so that by July the mlean rise has been 1 foot 5.6
inches.

In some instances the sudden variation is extreme, notably
in Wells Nos. 2 and 3 for the three years they are mapped. (See
Plates 3, 4, and 5). The greatest single variation occurs in Well
No. 2 in 1911. (See Plate No. 4). Between the seventeenth and
the twenty-sixth of April of that year the water level rose from
9 feet 11 inches to 5 feet 3.5 inches, a total rise of 4 feet 7.5
inches from a single irrigation a rise that undoubtedly proved
a serious injury to the fall sown grain crop whose roots had been
constantly growing downward during the winter as the water
level receded.

Prom this extreme condition we go nearly to the opposite in
a few instances where the level was but slightly, or not at all,
affected. (See Plate No. 4, June 11 ; Plate No. 5, July 17 ; also
Plate No. 12, June and August). This indicates that the irri-
gations preceding were either about right or scant in quantity.
At any rate the amount of water that passed into the country
drainage was very small.

In a few instances the water table shows a slight rise, before
the first spring irrigation on the ground immediately around the
well. (See Plate No. 5, April; Plate No. 6, March; Plate No. 10,
April, May and June; Plate No. 13, April). In these instances
it will be seen that the variations occur always after the first
irrigation on the farm, and are probably caused by the seepage
from the lands either above or below. It may be well to state
here that excessive quantities of water applied on land near
either 1, 2 or 3 will affect the level in the others; likewh'se Nos.


1

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