Drainage is the natural or artificial removal of surface and sub-surface water from an area. Many agricultural soils need drainage to
improve production or to manage water supplies.
Early history
The
ancient Indus systems of sewerage and drainage that
were developed and used in cities throughout the civilization were far more
advanced than any found in contemporary urban cites in the Middle
East
and even more efficient than those in some areas of modern Pakistan and India
today. All houses in the major cities of Harappa and Mohenjo-daro had access to water and drainage
facilities. Waste water was directed to covered drains, which lined the major
streets.
Drainage in the 19th century
This
operation is always best performed in spring or summer, when the ground is
dry. Main drains ought to be made in every part of the field where a cross-cut[disambiguation
needed] or open drain was
formerly wanted; they ought to be cut four feet (1.2 m) deep, upon an average.
This completely secures them from the possibility of being damaged by the
treading of horses or cattle, and being so far
below the small drains, clears the water finely out of them. In every
situation, pipe-turfs for the main drains, if they can be had, are preferable.
If good stiff clay, a single row of
pipe-turf; if sandy, a double row. When pipe-turf cannot be got conveniently, a
good wedge drain may answer well, when the subsoil is a strong, stiff clay; but
if the subsoil be only moderately so, a thorn drain, with couples below, will
do still better; and if the subsoil is very sandy, except pipes can be had, it
is in vain to attempt under-draining the field by any other method. It may be
necessary to mention here that the size of the main drains ought to be
regulated according to the length and declivity of the run, and t eihther it can
be he quantity of water to be carried off by them. It is always safe, however,
to have the main drains large, and plenty of them; for economy here seldom
turns out well.
Having
finished the main drains, proceed next to make a small drain in every furrow of
the field if the ridges formerly have not been less than fifteen feet (4.6 m)
wide. But if that should be the case, first level the ridges, and make the
drains in the best direction, and at such a distance from each other as may be
thought necessary. If the water rises well in the bottom of the drains, they
ought to be cut three feet (1 m) deep, and in this ease would dry the field
sufficiently well, although they were from twenty-five to thirty feet (8 to 10
m) asunder; but if the water does not draw well to the bottom of the drains,
two feet (0.6 m) will be a sufficient deepness for the pipe-drain, and two and
a half feet (1 m) for the wedge drain. In no case ought they to be shallower
where the field has been previously leveled. In this instance, however, as the
surface water is carried off chiefly by the water sinking immediately into the
top of the drains, it will be necessary to have the drains much nearer each
other—say from fifteen to twenty feet (4.6 to 6 m). If the ridges are more than
fifteen feet (4.6 m) wide, however broad and irregular they may be, follow
invariably the line of the old furrows, as the best direction for the drains;
and, where they are high-gathered ridges, from twenty to twenty-four inches
will be a sufficient depth for the pipe-drain, and from twenty-four to thirty
inches for the wedge-drain. Particular care
should be taken in connecting the small and main drains together, so that the
water may have a gentle declivity, with free access into the main drains.
When
the drains are finished, the ridges are cleaved down
upon the drains by the plough;
and where they had been very high formerly, a second clearing may be given; but
it is better not to level the ridges too much, for by allowing them to retain a
little of their former shape, the ground being lowest immediately where the
drains are, the surface water collects upon the top of the drains; and, by
shrinking into them, gets freely away. After the field is thus finished, run
the new ridges across the small drains, making them about ten feet (3 m) broad,
and continue afterwards to plough the field in the same manner as dry land.
It
is evident from the above method of draining that the expense will vary very
much, according to the quantity of main drains necessary for the field, the
distance of the small drains from each other, and the distance the turf is to
be carried.
The
advantage resulting from under-draining, is very great, for besides a
considerable saving annually of water furrowing, cross cutting, etc., the land
can often be ploughed and sown
to advantage, both in the spring and in the fall of the year, when otherwise it
would be found quite impracticable; every species of drilled crops, such as beans, potatoes, turnips, etc., can be
cultivated successfully; and every species, both of green and white crops, is
less apt to fail in wet and untoward seasons.
Wherever
a burst of water appears in any particular spot, the sure and certain way of
getting quit of such an evil is to dig hollow drains to such a depth below the
surface as is required by the fall or level that can be gained, and by the
quantity of water expected to proceed from the burst or spring.
Having ascertained the extent of water to be carried off, taken the necessary
levels, and cleared a mouth or loading passage for the water, begin the drain
at the extremity next to that leader, and go on with the work till the top of
the spring is touched, which probably will accomplish the intended object. But
if it should not be completely accomplished, run off from the main drain with
such a number of branches as may be required to intercept the water, and in
this way disappointment will hardly be experienced. Drains, to be substantially
useful, should seldom be less than three feet (1 m) in depth, twenty or twenty
four inches thereof to be close packed with stones or wood, according to
circumstances. The former are the best materials, but in many places are not to
be got in sufficient quantities; recourse therefore, must often be made to the
latter, though not so effectual or durable.
It
is of vast importance to fill up drains as fast as they are dug out; because,
if left open for any length of time, the earth is not only apt to fall in but
the sides get into a broken, irregular state, which cannot afterwards be
completely rectified. A proper covering of straw or sod should be put upon
the top of the materials, to keep the surface earth from mixing with them; and
where wood is the material used for filling up, a double degree of attention is
necessary, otherwise the proposed improvement may be effectually frustrated.
SUBSCRIBERS - ( LINKS) :FOLLOW / REF / 2 /
findleverage.blogspot.com
Krkz77@yahoo.com
+234-81-83195664
No comments:
Post a Comment