The circle banner. [volume] (Circle, Mont.) 1914-1939, 1922-07-21

WaLerlOBS1nS Oh Cne surface sui, due
in many instances, an accumulation
of alkaline salts, due to the evapora
ton of water from the surface. Prac
tically every valley in the west has
suffered to a greater or less extent
from the over-zealousness of the LAND
owners, and in some valleys con
siderable percentage of the lands is
now unproductive and often abandon.
ed
The water-logging of the soil is the
direct result of seepage from the irri-
CATION of the lands themselves;
seepage from lateral bitches, and to
small extent seepage from the sup
ply canals. The concentration of the
alkaline salt solution near the sur
face and the deposition of the alkal-
inc salts on the surface is the indir-
ect action. The remedy for the COM
bined evils is Understandings which
removes the excess moisture from
the soil space, directly, while the al
| kaline salts disappear as matter of
course, the action being just the re-
verse of that by which they made
their appearance.
BY lowering the water table, the
excess moisture already in the soil
is removed; fluctuations of the
ground water level are prevented,
and the percolation from subsequent
irrigation finds ready means of es-
cape. Vigorous cultivation of the
soil followed by copious irrigation
permits of the teaching out of the al
kaline salts by the downward move
ment of the water. The removal of
the excess moisture from the soil
spaces allows the air to enter and the
proper balance between air and
moisture is maintained, while the
soil is made warmer. The greater
root space afforded actually increases
the amount of available moisture and
the available plant food supply. Plow-
ing may be done earlier so the grow
ing Season is made both earlier and
longer.
While the direct action of under
drains is much the same in arid as in
humid regions, the ultimate results
desired and the methods of obtaining
them are vastly different. In the
humid sections drainage systems are
designed to remove a given depth of
period of time. This is usually ex-
pressed in terms of certain frac
ton of an inch in "a hours. In the
arid section the important thing isl
to prevent fluctuations of the ground
water level within the root zone,
which requires that the drainage sys-
tenn shall remove storm water as
rapidly as it falls and to care for per-
colating irrigation water and lateral
seepage from higher lying lands. Sys-
TENS must be designed, therefore, to
care for the maximum flow, and there
is usually continuous flow the year
round.
The root zone in the arid sections
to a considerable depth and
for ordinary conditions the ground
water level should not be permitted
to rise higher than five or six feet
from the surface. This calls for |
drains six feet or more in depth, |
which is greater than that usually
given to drains in the humid sections. |
Where alkaline salts are present, it
s especially important that ample
iepth be given, since these salts, be-
ng soluble, are concentrated at the
upper limit of saturation, which is
)ften several feet above the free
water level, owing to the capillary
of the SOIL
The greater depth of drains re-
luired and the necessity of providing
more generous capacity make the
init cost of constructing drains in
he arid section higher than in the
lumid. Labor and material are also
higher. Properly designed and care
ully constructed drains are effective
throughout a greater area, however,
n the arid sections so that the cost
# drainage is no more and often
ess than in the humid sections.
The drainage of irrigated lands has
,een reduced to a science and in
olives many technical considerations.
t is easy to make vital errors in loca-
ion and design of drainage systems
nd since the work is comparatively
lew and has received but little at
ention, there are but few men capa-
lie of handling the situation. The
reat importance of the work is be-
ng realized now, however, and much
areful study is being given the sub
ejct The construction of drainagel
works. is often extremely difficult and
resents problems that only special
SITS are competent to- handle.
The first experiments to determine
neither or not lands injured by seep-
ge water and alkaline salts could
e economically reclaimed were made
n Utah and many successful demon
trations were carried out. AS re-
ult of the success of these experi-1
nents a general movement toward
exclamation of the 100000 acres OIL