Perrysburg journal. (Perrysburg, Wood Co., O. [Ohio]) 186?-1965, 1871-10-13
How Do Drains Operate!

After conversation with several practi-
cal farmers, 1 am satisfied that many of
them do not fully understand the correct
theory of the action OF drains. To those
who do not give the matter their careful
attention, it will seem very simple matter
to understand how, when it rains, or
when from other causes water accumulates
in the soil, it should escape by sinking
down into awell-made drain but Just here
is where mistake is made, for the water
does not come into the drain from the top,
but from the bottom of the drain; or, in
other words, the surplus water comes up
into the drain, and not down into it. In
all low lands there is point at which the
soil remains saturated with water, and the
distance of this point from the surface will
OF course vary with the facility offered for
the discharge of the surplus water. Where
this point is so near the surface as to affect
the roots of the farmers crops, drains are
needed, and should be used, in order to
keep this line of saturation on level with
their bottoms. In order to simplify the
matter, this line of ssturation has been
styled the water table. In case of heavy
rsln, the water will sink down until Il
reaches this water, which, from the accu-
mutation of water, will gradually rise until
lin the absence of drains) it finds
a natural outlet. The amount of
damage done to the farmer
will, of course, depend upon the height of
this outlet; in some cases it is so high as
20 overflow the surface, and in others will
not reach the surface, but still is high
enough to do damage to the growing
crops.
To explain more clearly my meaning,
suppose barrel (water-tight) to be filled
with common soil, and small openings
made at different heights along its side; /;
now suppose water to be poured so slowly
upon the surface of the soil that it will be
absorbed rs fast as it is poured in-the
earth will reach point of saturation at
which it will hold no more water, and it
will accumulate at the bottom of the bar
rel. If the addition of water is continued,
the artificial water-table will rise, and the
surplus water will pass off at the lowest
openings; if the water is added faster than
one opening can carry it off 1t will rise to
the next above, and in this way will, If the
water is added fast enough, overflow the
top of the barrel. In all cases the surplus
water will rise to the lowest opening, and
not fall to and escape by the upper one.
This is exactly what takes place with a
drain. AS soon as the drain is opened it
lowers the water-table to its own level,
and if the water does not come In faster
than the drain can carry it of, will hold it
there.
In one case / was told by practical
farmer, who had drains in successful oper.
alton, that this idea was not correct, for if
it was, one drain would lower the water
table on an acre of ground, and should
prove sufficient to drain it properly. But
for the capillary attraction of the soil, this
objection would hold coed. Different
soils possess the power of holding wa er
in different degrees; aud hence no rule for
spacing drains will hold good; they may
be, and often are, so far apart that the
capillary attraction Of the so / entirely
counteracts the tendancy of the water to
seek the level of the drains and hence we
| find, where the drains are too far apart, that
the water table is not level, but rises nearly
or quite TO the surface, midway between
the drains, but over them falls to their
| level.
This liue of saturation is a wonderful
provision Of nature, whereby moisture is
furnished just as It is needed, and in
proper quantities, provided it is at the
proper distance from the surface. Ii this
point is too far from the surface, the pow er
of capillary attraction will be overcome by
the weight of waler-and if too near the
surface, the crop will be injured by its
roots c ming In contact with the water.
From what ! have already WIitten, We