VARIOUS METHODS OF DRAINAGE.
Open Ditches.--Slope of Banks.--Brush Drains.--Ridge and
Furrow.--Plug-Draining.--Mole-Draining.--Mole-Plow.--Wedge and
Shoulder Drains.--Larch Tubes.--Drains of Fence Rails, and
Poles.--Peat Tiles.--Stone Drains Injured by Moles.--Downing's
Giraffes.--Illustrations of Various Kinds of Stone Drains.
OPEN DITCHES.
The most obvious mode of getting rid of surface-water is, to cut a ditch
on the surface to a lower place, and let it run. So, if the only object
were to drain a piece of land merely for a temporary purpose--as, where
land is too wet to ditch properly in the first instance, and it is
necessary to draw off part of the surplus water before systematic
operations are commenced--an open ditch is, perhaps, the cheapest method
to be adopted.
Again: where land to be drained is part of a large sloping tract, and
water runs down, at certain seasons, in large quantities upon the
surface, an open catch-water-ditch may be absolutely necessary. This
condition of circumstances is very common in mountainous districts,
where the rain which falls on the hills flows down, either on the
visible surface or on the rock-formation under the soil, and breaks out
at the foot, causing swamps, often high up on the hill-sides. Often,
too, in clay districts, where sand or loam two or three feet deep rests
on tough clay, we see broad sloping tracts, which form our best
grass-fields.
If we are attempting to drain the lower part of such a slope, we shall
find that the water from the upper part flows down in large quantities
upon us, and an open ditch may be most economical as a header, to cut
off the down-flowing water; though, in most cases, a covered drain may
be as efficient.
At the outlets, too, of our tile or stone drains, when we come down
nearly to the level of the stream which receives our drainage-water, we
find it convenient, often, and indeed necessary, to use open
ditches--perhaps only a foot or two deep--to carry off the water
discharged. These ditches are of great importance, and should be
finished with care, because, if they become obstructed, they cause
back-water in the drains, and may ruin the whole work.
Open drains are thus essential auxiliaries to the best plans of thorough
drainage; and, whatever opinion may be entertained of their economy,
many farmers are so situated that they feel obliged to resort to them
for the present, or abandon all idea of draining their wet lands. We
will, therefore, give some hints as to the best manner of constructing
open drains; and then suggest, in the form of objections to them, such
considerations as shall lead the proprietor who adopts this mode to
consider carefully his plan of operations in the outset, with a view to
obviate, as much as possible, the manifest embarrassments occasioned by
them.
As to the location of drains in swamps and peculiarly wet places,
directions may be found in another chapter. We here propose only to
treat of the mode of forming open drains, after their location is fixed.
The worst of all drains is an open ditch, of equal width from top to
bottom. It cannot stand a single season, in any climate or soil, without
being seriously impaired by the frosts or the heavy rains. All open
drains should be sloping; and it is ascertained, by experiment, what is
the best, or, as it is sometimes expressed, the natural slope, on
different kinds of soil. If earth be tipped from a cart down a bank, and
be left exposed to the action of the weather, it will rest, and finally
remain, at a regular angle or inclination, varying from 21 deg. to 55 deg. with
the horizon, according to the nature of the soil. The natural slope of
common earth is found to be about 33 deg. 42'; and this is the inclination
usually adopted by railroad engineers for their embankments.
If the banks of the open ditch are thus sloped, they will have the least
possible tendency to wash away, or break down by frost.
Again: where open ditches are adopted in mowing fields, they may, if not
very deep, be sloped still lower than the natural slope, and seeded down
to the bottom; so that no land will be lost, and so that teams may pass
across them.
This amounts, in fact, to the old ridge and furrow system, which was
almost universal in England before tiles were used, and is sometimes
seen practiced in this country. The land, by that system, is
back-furrowed in narrow lands, till it is laid up into beds, sloping
from the tops, or backs, to the furrows which constitute the drains.
This mode of culture is very ancient, and is probably referred to in the
language of the Psalmist, in the Scriptures: "Thou waterest the ridges
thereof abundantly, thou settlest the furrows thereof, thou makest it
soft with showers."
The objections to open ditches, as compared with under-drains, may be
briefly stated thus:
1. _They are expensive._ The excavation of a sloping drain is much
greater than that of an upright drain. An open drain must have a width
of one or two feet at the bottom, to receive the earth that always must,
to some extent, wash into it. An open drain requires to be cleaned out
once a year, to keep it in good order. There is a large quantity of
earth from an open drain to be disposed of, either by spreading or
hauling away. Thus, a drain of this kind is costly at the outset, and
requires constant labor and care to preserve it in working condition.
2. _They are not permanent._ A properly laid underdrain will last half a
century or more, but an open drain, especially if deep, has a constant
tendency to fill up. Besides, the action of frost and water and
vegetation has a continual operation to obstruct open ditches. Rushes
and water-grasses spring up luxuriantly in the wet and slimy bottom, and
often, in a single season, retard the flow of water, so that it will
stand many inches deep where the fall is slight. The slightest accident,
as the treading of cattle, the track of a loaded cart, the burrowing of
animals, dams up the water and lessens the effect of the drain. Hence,
we so often see meadows which have been drained in this way going back,
in a few years, into wild grass and rushes.
3. _They obstruct good husbandry._ In the chapter upon the effects of
drainage on the condition of the soil, we suggest, in detail, the
hindrances which open ditches present to the convenient cultivation of
the land, and, especially, how they obstruct the farmer in his plowing,
his mowing, his raking, and the general laying out of his land for
convenient culture.
4. _They occupy too much land._ If a ditch have an upright bank, it is
so soft that cattle will not step within several feet of it in plowing,
and thus a strip is lost for culture, or must be broken up by hand. If,
indeed, we can get the plow near it, there being no land to rest
against, the last furrow cannot be turned from the ditch, and if it be
turned into it, must be thrown out by hand. If the banks be sloped to
the bottom, and the land be thus laid into beds or ridges, the
appearance of the field may, indeed, be improved, but there is still a
loss of soil; for the soil is all removed from the furrow, which will
always produce rushes and water-grass, and carried to the ridge, where
it doubles the depth of the natural soil. Thus, instead of a field of
uniform condition, as to moisture and temperature and fertility, we have
strips of wet, cold, and poor soil, alternating with dry, warm, and rich
soil, establishing a sort of gridiron system, neither beautiful,
convenient, nor profitable.
5. _The manure washes off and is lost._ The three or four feet of water
which the clouds annually give us in rain and snow, must either go off
by evaporation, or by filtration, or run off upon the surface. Under the
title of Rain and Evaporation, it will be seen that not much more than
half this quantity goes off by evaporation, leaving a vast quantity to
pass off through or upon the soil. If lands are ridged up, the manure
and finer portions of the soil are, to a great extent, washed away into
the open ditches and lost. Of the water which filters downwards, a large
portion enters open ditches near the surface, before the fertilizing
elements have been strained out; whereas, in covered drains of proper
depth, the water is filtered through a mass of soil sufficiently deep to
take from it the fertilizing substances, and discharge it, comparatively
pure, from the field. In a paper by Prof. Way (11th Jour. Roy. Ag.
Soc.), on "The Power of Soils to retain Manure," will be found
interesting illustrations of the filtering qualities of different kinds
of soil.
In addition to the above reasons for preferring covered drains, it has
been asserted by one of the most skillful drainers in the world (Mr.
Parkes), "that a proper covered drain of the same depth as an open
ditch, will drain a greater breadth of land than the ditch can effect.
The sides of the ditch," he says, "become dried and plastered, and
covered with vegetation; and even while they are free from vegetation,
their absorptive power is inferior to the covered drain."
Of the depth, direction, and distance of drains, our views will be found
under the appropriate heads. They apply alike to open and covered
drains.
BRUSH DRAINS.
Having a farm destitute of stones, before tiles were known among us, we
made several experiments with covered drains filled with brush. Some of
those drains operated well for eight or ten years; others caved in and
became useless in three or four years, according to the condition of the
soil.
In a wet swamp a brush drain endures much longer than in sandy land,
which is dry a part of the year, because the brush decays in dry land,
but will prove nearly imperishable in land constantly wet. In a peat or
muck swamp, we should expect that such drains, if carefully constructed,
might last twenty years, but that in a sandy loam they would be quite
unreliable for a single year.
Our failure on upland with brush drains, has resulted, not from the
decay of the wood, but from the entrance of sand, which obstructed the
channel. Moles and field-mice find these drains the very day they are
laid, and occupy them as permanent homes ever after.
Those little animals live partly upon earth-worms, which they find by
burrowing after them in the ground, and partly upon insects, and
vegetation above ground. They have a great deal of business, which
requires convenient passages leading from their burrows to the
day-light, and drains in which they live will always be found perforated
with holes from the surface. In the Spring, or in heavy showers, the
water runs in streams into these holes, breaks down the soft soil as it
goes, and finally the top begins to fall in, and the channel is choked
up, and the work ruined. We have tried many precautions against this
kind of accident, but none that was effectual on light land.
The general mode of construction is this: Open the trench to the depth
required, and about 12 inches wide at the bottom. Lay into this poles of
four or five inches diameter at the butt, leaving an open passage
between. Then lay in brush of any size, the coarsest at the bottom,
filling the drain to within a foot of the surface, and covering with
pine, or hemlock, or spruce boughs. Upon these lay turf, carefully cut,
as close as possible. The brush should be laid but-end up stream, as it
obstructs the water less in this way. Fill up with soil a foot above the
surface, and tread it in as hard as possible. The weight of earth will
compress the brush, and the surface will settle very much. We have tried
placing boards at the sides, and upon the top of the brash, to prevent
the caving in, but with no great success. Although our drains thus laid,
have generally continued to discharge some water, yet they have, upon
upland, been dangerous traps and pitfalls for our horses and cattle, and
have cost much labor to fill up the holes, where they have fallen
through by washing away below.
In clay, brush drains might be more durable. In the English books, we
have descriptions of drains filled with thorn cuttings from hedges and
with gorse. When well laid in clay, they are said to last about 15
years. When the thorns decay, the clay will still retain its form, and
leave a passage for the water.
A writer in the Cyclopedia sums up the matter as to this kind of drains,
thus:
"Although in some districts they are still employed, they can only
be looked upon as a clumsy, and superficial plan of doing that
which can be executed in a permanent and satisfactory manner, at a
very small additional expense, now that draining-tiles are so cheap
and plentiful."
Draining-tiles are not yet either cheap or plentiful in this country;
but we have full faith that they will become so very soon. In the mean
time it may be profitable for us to use such of the substitutes for them
as may lie within our reach, selecting one or another according as
material is convenient.
PLUG-DRAINING
has never been, that we are aware, practiced in America. Our knowledge
of it is limited to what we learn from English books. We, therefore,
content ourselves with giving from Morton's Cyclopedia the following
description and illustrations.
"_Plug-draining_, like mole-draining, does not require the use of
any foreign material--the channel for the water being wholly formed
of clay, to which this kind of drain, like that last mentioned is
alone suited.
"This method of draining requires a particular set of tools for its
execution, consisting of, first, a common spade, by means of which
the first spit is removed, and laid on one side; second, a
smaller-sized spade, by means of which the second spit is taken
out, and laid on the opposite side of the trench thus formed;
third, a peculiar instrument called a bitting iron (Fig. 11),
consisting of a narrow spade, three and a half feet in length, and
one and a half inches wide at the mouth and sharpened like a
chisel; the mouth, or blade, being half an inch in thickness in
order to give the necessary strength to so slender an implement.
From the mouth, _a_, on the right-hand side, a ring of steel, _b_,
six inches long and two and a half broad, projects at right angles;
and on the left, at fourteen inches from the mouth, a tread, _c_,
three inches long, is fitted.
[Illustration: Fig. 11.]
"A number of blocks of wood, each one foot long, six inches high,
and two inches thick at the bottom, and two and a half at the top,
are next required. From four to six of these are joined together by
pieces of hoop-iron let into their sides by a saw-draught, a small
space being left between their ends, so that when completed, the
whole forms a somewhat flexible bar, as shown in the cut, to one
end of which a stout chain is attached. These blocks are wetted,
and placed with the narrow end undermost, in the bottom of the
trench, which should be cut so as to fit them closely; the clay
which has been dug out is then to be returned, by degrees, upon the
blocks, and rammed down with a wooden rammer three inches wide. As
soon as the portion of the trench above the blocks, or plugs, has
been filled, they are drawn forward, by means of a lever thrust
through a link of the chain, and into the bottom of the drain for a
fulcrum, until they are all again exposed, except the last one. The
further portion of the trench, above the blocks, is now filled in
and rammed, and so on the operations proceed until the whole drain
is finished."
[Illustration: Fig. 12.--PLUG DRAINAGE.]
MOLE DRAINING.
We hear of an implement, in use in Illinois and other Western States,
called the Gopher Plow, worked by a capstan, which drains wet land by
merely drawing through it an iron shoe, at about two and a half feet in
depth, without the use of any foreign substance.
We hear reports of a mole plow, in use in the same State, known by the
name of Marcus and Emerson's Patent Subsoiler, with which, an informant
says, drains are made also in the manner above named. This machine is
worked by a windlass power, by a horse or yoke of oxen, and the price
charged is twenty-eight cents a rod for the work. These machines are,
from description, modifications of the English Mole Plow, an implement
long ago known and used in Great Britain.
[Illustration: Fig. 13.--MOLE PLOW.]
The following description is from Morton's Cyclopedia:
"_Mole-Drains_ are the simplest of all the forms of the covered
drains. They are formed by means of a machine called the mole plow.
This machine consists of a long wooden beam and stilts, somewhat in
the form of the subsoil plow; but instead of the apparatus for
breaking up the subsoil in the latter, a short cylindrical and
pointed bar of iron is attached, horizontally, to the lower end of
the broad coulter, which can be raised or lowered by means of a
slot in the beam. The beam itself is sheathed with iron on the
under side, and moves close to the ground; thus keeping the bar at
the end of the coulter at one uniform depth. This machine is
dragged through the soft clay, which is the only kind of land on
which it can be used with propriety, by means of a chain and
capstan, worked by horses, and produces a hollow channel very
similar to a mole-run, from which it derives its name."
A correspondent of the _New York Tribune_ thus describes the operation
and utility of a mole plow, which he saw on the farm of Major A. B.
Dickinson, of Hornby, Steuben County, New York:
"I believe there is not a rod of tile laid on this farm, and not a
dozen rods of covered stone drain. But the major has a home-made,
or, at least, home-devised, 'bull plow,' consisting of a
sharp-pointed iron wedge, or roller, surmounted by a broad, sharp
shank nearly four feet high, with a still sharper cutter in front,
and with a beam and handles above all. With five yoke of oxen
attached, this plow is put down through the soil and subsoil to an
average depth of three feet--in the course which the superfluous
water is expected and desired to take--and the field thus plowed
through and through, at intervals of two rods, down to three feet,
as the ground is more or less springy and saturated with water. The
cut made by the shank closes after the plow and is soon
obliterated, while that made by the roller, or wedge, at the
bottom, becomes the channel of a stream of water whenever there is
any excess of moisture above its level, which stream tends to clear
itself and rather enlarge its channel. From ten to twenty acres a
day are thus drained, and Major D. has such drains of fifteen to
twenty years' standing, which still do good service. In rocky
soils, this mode of draining is impracticable: in sandy tracts it
would not endure; but here it does very well, and, even though it
should hold good in the average but ten years, it would many times
repay its cost."
Major Dickinson himself in a recent address, thus speaks of what he
calls his
SHANGHAE PLOW.
"I will take the poorest acre of stubble ground, and if too wet for
corn in the first place, I will thoroughly drain it with a Shanghae
plow and four yoke of oxen in three hours.
"I will suppose the acre to be twenty rods long and eight rods
wide. To thoroughly drain the worst of your clay subsoil, it may
require a drain once in eight feet, and they can be made so cheaply
that I can afford to make them at that distance. To do so, will
require the team to travel sixteen times over the twenty rods
lengthwise, or one mile in three hours; two men to drive, one to
hold the plow, one to ride the beam, and one to carry the crow-bar,
pick up any large stones thrown out by going to the right or left,
and to help to carry around the plow, which is too heavy for the
other two to do quickly.
"The plow is quite simple in its construction, consisting of a
round piece of iron three and a half or four inches in diameter,
drawn down to a point, with a furrow cut in the top one and a half
inches deep; a plate, eighteen inches wide and three feet long,
with one end welded into the furrow of the round bar, while the
other is fastened to the beam. The coulter is six inches in width,
and is fastened to the beam at one end, and at the other to the
point of the round bar. The coulter and plate are each
three-fourths of an inch thick, which is the entire width of the
plow above the round iron at the bottom.
"It would require much more team to draw this plow on some soils
than on yours. The strength of team depends entirely on the
character of the subsoil. Cast-iron, with the exception of the
coulter, for an easy soil would be equally good; and from eighteen
to twenty-four inches is sufficiently deep to run the plow. I can
as thoroughly drain an acre of ground in this way as any that can
be found in Seneca County."
From the best information we can gather, it would seem, that on certain
soils with a clay subsoil, the mole plow, as a sort of pioneer
implement, may be very useful. The above account certainly indicates
that on the farm in question it is very cheap, rapid, and effectual in
its operation.
Stephens gives a minute description of the mole plow figured above, in
his Book of the Farm. Its general structure and principle of operation
may be easily understood by what has been already said, and any person
desirous of constructing one may find in that work exact directions.
WEDGE AND SHOULDER DRAINS.
These, like the last-mentioned kind of drains, are mere channels formed
in the subsoil. They have, therefore, the same fault of want of
durability, and are totally unfitted for land under the plow. In forming
_wedge-drains_, the first spit, with the turf attached, is laid on one
side, and the earth removed from the remainder of the trench is laid on
the other. The last spade used is very narrow, and tapers rapidly, so as
to form a narrow wedge-shaped cavity for the bottom of the trench. The
turf first removed is then cut into a wedge, so much larger than the
size of the lower part of the drain, that when rammed into it with the
grassy side undermost, it leaves a vacant space in the bottom six or
eight inches in depth, as in Fig. 14.
The _shoulder-drain_ does not differ very materially from the
wedge-drain. Instead of the whole trench forming a gradually tapering
wedge, the upper portion of the shoulder-drain has the sides of the
trench nearly perpendicular, and of considerable width, the last spit
only being taken out with a narrow, tapering spade, by which means a
shoulder is left on either side, from which it takes its name. After the
trench has been finished, the first spit, having the grassy side
undermost as in the former case, is placed in the trench, and pushed
down till it rests upon the shoulders already mentioned; so that a
narrow wedge-shaped channel is again left for the water, as shown in
Fig. 15.
[Illustration: Fig. 14.--WEDGE-DRAIN.]
[Illustration: Fig. 15.--SHOULDER-DRAIN.]
These drains may be formed in almost any kind of land which is not a
loose gravel or sand. They are a very cheap kind of drain; for neither
the cost of cutting nor filling in, much exceeds that of the ordinary
tile drain, while the expense of tiles or other materials is altogether
saved. Still, such drains cannot be recommended, for they are very
liable to injury, and, even under the most favorable circumstances, can
only last a very limited time.
LARCH TUBES.
These have been used in Scotland, in mossy or swampy soils, it is said,
with economy and good results. The tube represented below presents a
square of 4 inches outside, with a clear water-way of 2 inches. Any
other durable wood will, of course, answer the same purpose. The tube is
pierced with holes to admit the water. In wet meadows, these tubes laid
deep would be durable and efficient, and far more reliable than brush or
even stones, because they may be better protected from the admission of
sand and the ruinous working of vermin. Their economy depends upon the
price of the wood and the cost of tiles--which are far better if they
can be reasonably obtained.
[Illustration: Fig. 16.--LARCH TUBE-DRAIN.]
Near Washington, D. C., we know of drainage tolerably well performed by
the use of common fence-rails. A trench is opened about three inches
wider at bottom than two rails. Two rails are then laid in the bottom,
leaving a space of two or three inches between them. A third rail is
then laid on for a cover, and the whole carefully covered with turf or
straw, and then filled up with earth. Poles of any kind may be used
instead of rails, if more convenient.
In clay, these drains would be efficient and durable; in sand, they
would be likely to be filled up and become useless. This is an
extravagant waste of timber, except in the new districts where it is of
no value.
Mr. J. F. Anderson, of Windham, Maine, has adopted a mode of draining
with poles, which, in regions where wood is cheap and tiles are dear,
may be adopted with advantage.
Two poles, of from 3 to 6 inches diameter, are laid at the bottom of the
ditch, with a water-way of half their diameter between them. Upon these,
a third pole is laid, thus forming a duct of the desired dimensions.
The security of this drain will depend upon the care with which it is
protected by a covering of turf and the like, to prevent the admission
of earth, and its permanency will depend much upon its being placed low
enough to be constantly wet, as such materials are short-lived when
frequently wet and dried, and nearly imperishable if constantly wet. It
is unnecessary to place brush or stones over such drains to make them
draw, as it is called. The water will find admission fast enough to
destroy the work, unless great care is used.
[Illustration: Fig. 17.--POLE-DRAIN.]
In Ireland, and in some parts of England and Scotland, peat-tiles are
sometimes used in draining bogs. They are cheap and very durable in such
localities, but, probably, will not be used in this country. They are
formed somewhat like pipes, of two pieces of peat. Two halves are formed
with a peculiar tool, with a half circle in each. When well dried, they
are placed together, thus making a round opening.
[Illustration: Fig. 18.--TOOL FOR PEAT-TILES.]
[Illustration: Fig. 19.--PEAT-TILES.]
In draining, the object being merely to form a durable opening in the
soil, at suitable depth, which will receive and conduct away the water
which filters through the soil, it is obvious that a thousand expedients
may be resorted to, to suit the peculiar circumstances of persons. In
general, the danger to be apprehended is from obstruction of the
water-way. Nothing, except a tight tube of metal or wood, will be likely
to prevent the admission of water.
Economy and durability are, perhaps, the main considerations. Tiles, at
fair prices, combine these qualities better than anything else. Stones,
however, are both cheap and durable, so far as the material is
concerned; but the durability of the material, and the durability of the
drains, are quite different matters.
DRAINS OF STONES.
Providence has so liberally supplied the greater part of New England
with stones, that it seems to most inexperienced persons to be a work of
supererogation, almost, to manufacture tiles or any other draining
material for our farms.
We would by no means discourage the use of stones, where tiles cannot be
used with greater economy. Stone drains are, doubtless, as efficient as
any, so long as the water-way can be kept open. The material is often
close at hand, lying on the field and to be removed as a nuisance, if
not used in drainage. In such cases, true economy may dictate the use of
them, even where tiles can be procured; though, we believe, tiles will
be found generally cheaper, all things considered, where made in the
neighborhood.
In treating of the cost of drainage, we have undertaken to give fair
estimates of the comparative cost of different materials.
Every farmer is capable of making estimates for himself, and of testing
those made by us, and so of determining what is true economy in his
particular case.
The various modes of constructing drains of stones, may be readily shown
by simple illustrations:
[Illustration: Fig. 20.]
[Illustration: Fig. 21.]
[Illustration: Fig. 22.]
[Illustration: Fig. 23.]
If stone-drains are decided upon, the mode of constructing them will
depend upon the kind of stone at hand. In some localities, round
pebble-stones are found scattered over the surface, or piled in heaps
upon our farms; in others, flat, slaty stones abound, and in others,
broken stones from quarries may be more convenient. Of these, probably,
the least reliable is the drain filled with pebble-stones, or broken
stones of small size. They are peculiarly liable to be obstructed,
because there is no regular water-way, and the flow of the water must,
of course, be very slow, impeded as it is by friction at all points with
the irregular surfaces.
Sand, and other obstructing substances, which find their way, more or
less, into all drains, are deposited among the stones--the water having
no force of current sufficient to carry them forward--and the drain is
soon filled up at some point, and ruined.
Miles of such drains have been laid on many New England farms, at shoal
depths, of two or two and a half feet, and have in a few years failed.
For a time, their effect, to those unaccustomed to under-drainage, seems
almost miraculous. The wet field becomes dry, the wild grass gives place
to clover and herds-grass, and the experiment is pronounced successful.
After a few years, however, the wild grass re-appears, the water again
stands on the surface, and it is ascertained, on examination, that the
drain is in some place packed solid with earth, and is filled with
stagnant water.
The fault is by no means wholly in the material. In clay or hard pan,
such a drain may be made durable, with proper care, but it must be laid
deep enough to be beyond the effect of the treading of cattle and of
loaded teams, and the common action of frost. They can hardly be laid
low enough to be beyond the reach of our great enemy, the mole, which
follows relentlessly all our operations.
We recollect the remarks of Mr. Downing about the complaints in New
England, of injury to fruit-trees by the gnawing of field-mice.
He said he should as soon think of danger from injury by giraffes as
field-mice, in his own neighborhood, though he had no doubt of their
depredations elsewhere!
It may seem to many, that we lay too much stress on this point, of
danger from moles and mice. We know whereof we do testify in this
matter. We verily believe that we never finished a drain of brush or
stones, on our farm, ten rods long, that there was not a colony of these
_varmint_ in the one end of it, before we had finished the other. If
these drains, however, are made three or four feet deep, and the solid
earth rammed hard over the turf, which covers the stones, they will be
comparatively safe.
The figures 24 and 25 below, represent a mode of laying stone drains,
practiced in Ireland, which will be found probably more convenient and
secure than any other method, for common small drains. A flat stone is
set upright against one side of the ditch, which should be near the
bottom, perpendicular. Another stone is set leaning against the first,
with its foot resting against the opposite bank. If the soil be soft
clay, a flat stone may be placed first on the bottom of the ditch, for
the water to flow upon; but this will be found a great addition to the
labor, unless flat stones of peculiarly uniform shape and thickness are
at hand. A board laid at the bottom will be usually far cheaper, and
less liable to cause obstructions.
[Illustration: Figs. 24, 25.--STONE DRAINS.]
Figure 25 represents the ditch without the small stones above the duct.
These small stones are, in nine cases in ten, worse than useless, for
they are not only unnecessary to admit the water, but furnish a harbor
for mice and other vermin.
Drawings, representing a filling of small stones above the duct, have
been copied from one work to another for generations, and it seems never
to have occurred, even to modern writers, that the small stones might be
omitted. Any one, who knows anything of the present system of draining
with tiles, must perceive at once that, if we have the open triangular
duct or the square culvert, the water cannot be kept from finding it, by
any filling over it with such earth as is usually found in ditching.
Formerly, when tiles were used, the ditch was filled above the tiles, to
the height of a foot or more, with broken stones; but this practice has
been everywhere abandoned as expensive and useless.
An opening of any form, equal to a circle of two or three inches
diameter, will be sufficient in most cases, though the necessary size of
the duct must, of course, depend on the quantity of water which may be
expected to flow in it at the time of the greatest flood.
Whatever the form of the stone drain, care should be taken to make the
joints as close as possible, and turf, shavings, straw, tan, or some
other material, should be carefully placed over the joints, to prevent
the washing in of sand, which is the worst enemy of all drains.
It is not deemed necessary to remark particularly upon the mode of
laying large drains for water-courses, with abutments and covering
stones, forming a square duct, because it is the mode universally known
and practiced. For small drains, in thorough-draining lands, it may,
however, be remarked, that this is, perhaps, the most expensive of all
modes, because a much greater width of excavation is necessary in order
to place in position the two side stones and leave the requisite space
between them. That mode of drainage which requires the least excavation
and the least carriage of materials, and consequently the least filling
up and levelling, is usually the cheapest.
Our conclusion as to stone drains is, that, at present, they may be, in
many cases, found useful and economical; and even where tiles are to be
procured at present prices stones may well be used, where materials are
at hand, for the largest drains.