Where it is thought best to connect an open, or surface drain, with a covered drain, it will add much to its security against silt and other obstructions, to interpose a trap or silt-basin at the junction, and thus allow the water to pass off comparatively clean. Where, however, there is a large flow of water into a basin, it will be kept so much in motion as to carry along with it a large amount of earth, and thus endanger the drain below, unless it be very large.
DISTANCES APART, OR FREQUENCY OF DRAINS.
The reader, who has studied carefully the rival systems of "deep drainage" and "thorough drainage," has seen that the distance of drains apart, is closely connected with that controversy. The greatest variety of opinion is expressed by different writers as to the proper distances, ranging all the way from ten feet apart to seventy, or even more.
Many English writers have ranged themselves on one side or the other of some sharp controversy as to the merits of some peculiar system. Some distinguished geologist has discovered, or thinks he has, some new law of creation by which he can trace the underground currents of water; or some noble noble lord has "patronized" into notice some caprice of an aspiring engineer, and straight-way the kingdom is convulsed with contests to set up or cast down these idols. By careful observation, it is said, we may find "sermons in stones, and good in everything;" and, standing aloof from all exciting controversies, we may often profit, not only by the science and wisdom of our brethren, but also by their errors and excesses. If, by the help of the successes and failures of our English neighbors, we shall succeed in attaining to their present standard of perfection in agriculture, we shall certainly make great advances upon our present position.
As the distances of drains apart, depend manifestly on many circumstances, which may widely vary in the diversity of soil, climate, and cost of labor and materials to be found in the United States, it will be convenient to arrange our remarks on the subject under appropriate heads.
DISTANCES DEPEND UPON THE NATURE OF THE SOIL.
Water runs readily through sand or gravel. In such soils it easily seeks and finds its level. If it be drawn out at one point, it tends towards that point from all directions. In a free, open sand, you may draw out all the water at one opening, almost as readily as from an open pond.
Yet, even such sands may require draining. A body of sandy soil frequently lies not only upon clay, but in a basin; so that, if the sand were removed, a pond would remain. In such a case, a few deep drains, rightly placed, might be sufficient. This, however, is a case not often met with, though open, sandy soil upon clay is a common formation.
Then there is the other extreme of compact clay, through which water seems scarcely to percolate at all. Yet it has water in it, that may probably soak out by the same process by which it soaked in. Very few soils, of even such as are called clay, are impervious to water, especially in the condition in which they are found in nature. To render them impervious, it is necessary to wet and stir them up, or, as it is termed, puddle them. Any soil, so far as it has been weathered—that is, exposed to air, water and frost—is permeable to water to a greater or less degree; so that we may feel confident that the upper stratum of any soil, not constantly under water, will readily allow the water to pass through.
And in considering the "Drainage of Stiff Clays," we shall see that the most obstinate clays are usually so affected by the operation of drainage, that they crack, and so open passages for the water to the drains.
All gravels, black mud of swamps, and loamy soils of any kind, are readily drained.
Occasionally, however—even in tracts of easy drainage, as a whole—deposits are found of some combinations with iron, so firmly cemented together, as to be almost impenetrable with the pick-axe, and apparently impervious to water. Exceptional cases of this nature must be carefully sought for by the drainer.
Whenever a wet spot is observed, seek for the cause, and be satisfied whether it is wet because a spring bursts up from the bottom; or because the subsoil is impervious, and will not allow the surface-water to pass downward. Ascertain carefully the cause of the evil, and then skillfully doctor the disease, and not the symptoms merely. A careful attention to the theory of moisture, will go far to enable us properly to determine the requisite frequency of drains.
DISTANCES DEPEND UPON THE DEPTH OF THE DRAINS.
The relations of the depth and distance of drains will be more fully considered, in treating of the depth of drains. The idea that depth will compensate for frequency, in all cases, seems now to be abandoned. It is conceded that clay-soils, which readily absorb moisture, and yet are strongly retentive, cannot be drained with sufficient rapidity, or even thoroughness, by drains at any depth, unless they are also within certain distances.
In a porous soil, as a general rule, the deeper the drain, the further it will draw. The tendency of water is to lie level in the soil; but capillary attraction and mechanical obstructions offer constant resistance to this tendency. The farther water has to pass in the soil, the longer time, other things being equal, will be required for the passage. Therefore, although a single deep drain might, in ten days lower the water-line as much as two drains of the same depth, or, in other words, might draw the water all down to its own level, yet, it is quite evident that the two drains might do the work in less time—possibly, in five days. We have seen already the necessity of laying drains deep enough to be below the reach of the subsoil plow and below frost, so that, in the Northern States, the question of shallow drainage seems hardly debatable. Yet, if we adopt the conclusion that four feet is the least allowable depth, where an outfall can be found, there may be the question still, whether, in very open soils, a still greater depth may not be expedient, to be compensated by increased distance.
DISTANCES DEPEND UPON CLIMATE.
Climate includes the conditions of temperature and moisture, and so, necessarily, the seasons. In the chapter which treats of Rain, it will be seen that the quantity of rain which falls in the year is singularly various in different places. Even, in England, "the annual average rain-fall of the wettest place in Cumberland is stated to be 141 inches, while 19-1/2 inches may be taken as the average fall in Essex. In Cumberland, there are 210 days in the year in which rain falls, and in Chiswick, near London, but 124."
A reference to the tables in another place, will show us an infinite variety in the rain-fall at different points of our own country.
If we expect, therefore, to furnish passage for but two feet of water in the year, our drains need not be so numerous as would be necessary to accommodate twice that quantity, unless, indeed, the time for its passage may be different; and this leads us to another point which should ever be kept in mind in New England—the necessity of quick drainage. The more violent storms and showers of our country, as compared with England, have been spoken of when considering The Size of Tiles. The sudden transition from Winter to Summer, from the breaking up of deep snows with the heavy falls of rain, to our brief and hasty planting time, requires that our system of drainage should be efficient, not only to take off large quantities of water, but to take them off in a very short time. How rapidly water may be expected to pass off by drainage, is not made clear by writers on the subject.
"One inch in depth," says an English writer, "is a very heavy fall of rain in a day, and it generally takes two days for the water to drain fully from deep drained land." One inch of water over an acre is calculated to be something more than one hundred tons. This seems, in gross, to be a large amount, but we should expect that an inch, or even two inches of water, spread evenly over a field, would soon disappear from the surface; and if not prevented by some impervious obstruction, it must continue downward.
It is said, on good authority, that, in England, the smallest sized pipes, if the fall be good, will be sufficiently large, at ordinary distances, to carry off all the surplus water. In the author's own fields, where two-inch tiles are laid at four feet depth and fifty feet apart, in an open soil, they seem amply sufficient to relieve the ground of all surplus water from rain, in a very few days. Most of them have never ceased to run every day in the year, but as they are carried up into an undrained plain, they probably convey much more water than falls upon the land in which they lie.
So far as our own observation goes, their flow increases almost as soon as rain begins to fall, and subsides, after it ceases, about as soon as the water in the little river into which they lead, sinks back into its ordinary channel, the freshet in the drains and in the stream being nearly simultaneous. Probably, two-inch pipes, at fifty feet distances, will carry off, with all desirable rapidity, any quantity of water that will ever fall, if the soil be such that the water can pass through it to the distance necessary to find the drains; but it is equally probable that, in a compact clay soil, fifty feet distance is quite too great for sufficiently rapid drainage, because the water cannot get to the drains with sufficient rapidity.
DISTANCES DEPEND UPON THE COMPARATIVE PRICES OF LABOR AND TILES.
The fact, that the last foot of a four-foot drain costs as much labor as the first three feet, is shown in another chapter, and the deeper we go, the greater the comparative cost of the labor. With tiles at $10 per thousand, the cost of opening and filling a four-foot ditch is, in, round numbers, by the rod, equal to twice the cost of the tiles. In porous soils, therefore, where depth may be made to compensate for greater distance, it is always a matter for careful estimate, whether we shall practice true economy by laying the tiles at great depths, or at the smallest depth at which they will be safe from frost and the subsoil plow, and at shorter distances. The rule is manifest that, where labor is cheap and tiles are dear, it is true economy to dig deep and lay few tiles; and, where tiles are cheap and labor is dear, it is economy to make the number of drains, if possible, compensate for less depth.
DISTANCES DEPEND UPON SYSTEM.
While we would not lay down an arbitrary arrangement for any farm, except upon a particular examination, and while we would by no means advocate what has been called the gridiron system—of drains everywhere at equal depths and distances—yet some system is absolutely essential, in any operation that approaches to thorough drainage.
If it be only desired to cut off some particular springs, or to assist Nature in some ravine or basin, a deep drain here and there may be expedient; but when any considerable surface is to be drained, there can be no good work without a connected plan of operations.
Mains must be laid from the outfall, through the lowest parts; and into the mains the smaller drains must be conducted, upon such a system as that there may be the proper fall or inclination throughout, and that the whole field shall be embraced.
Again, a perfect plan of the completed work, accurately drawn on paper, should always be preserved for future reference. Now it is manifest, that it is impossible to lay out a given field, with proper mains and small drains, dividing the fall as equally as practicable between the different parts of an undulating field, preserving a system throughout, by which, with the aid of a plan, any drain may at any time be traced, without making distances conform somewhat to the system of the whole.
It is easily demonstrable, too, that drains at right angles with the mains, and so parallel with each other, are the shortest possible drains in land that needs uniform drainage. They take each a more uniform share of the water, and serve a greater breadth of soil than when laid at acute angles. While, therefore, it may be supposed that in particular parts of the field, distances somewhat greater or less might be advisable, considered independently, yet in practice, it will be found best, usually, to pay becoming deference to order, "Heaven's first law," and sacrifice something of the individual good, to the leading idea of the general welfare.
In the letter of Mr. Denton, in another chapter, some remarks will be found upon the subject of which we are treating. The same gentleman has, in a published paper, illustrated the impossibility of strict adherence to any arbitrary rule in the distances or arrangement of drains, as follows:
"The wetness of land, which for distinction's sake, I have called 'the water of pressure,' like the water of springs, to which it is nearly allied, can be effectually and cheaply removed only by drains devised for, and devoted to the object. Appropriate deep drains at B B B, for instance, as indicated in the dark vertical lines, are found to do the service of many parallel drains, which as frequently miss, as they hit, those furrows, or 'lips,' in the horizontal out-crop of water-bearing strata which continue to exude wetness after the higher portions are dry.
"A consideration, too, of the varying inclinations of surface, of which instances will frequently occur in the same field, necessitates a departure from uniformity, not in direction only, but in intervals between drains. Take, for instance, the ordinary case of a field, in which a comparatively flat space will intervene between quickly rising ground and the outfall ditch. It is clear that the soak of the hill will pervade the soil of the lower ground, let the system of drainage adopted be what it may; and, therefore, supposing the soil of the hill and flat to be precisely alike, the existence of bottom water in a greater quantity in the lower lands than in the higher, will call for a greater number of drains. It is found, too, that an independent discharge or relief of the water coming from the hill, at B, should always be provided, in order to avoid any impediment by the slower flow of the flatter drains.
"Experience shows that, with few exceptions, hollows, or 'slacks,' observable on the surface, as at B B, have a corresponding undulation of subsoil and that any system which does not provide a direct release for water, which would otherwise collect in and draw towards these spots, is imperfect and unsatisfactory. It is found to be much more safe to depend on relief drains, than on the cutting of drains sufficiently deep through the banks, at A A, to gain a fall at a regular inclination.
"Still, in spite of experience, we often observe a disregard of these facts, even in works which are otherwise well executed to a depth of four feet, but fettered by methodical rules, and I feel compelled to remark, that it has often occurred to me, when I have observed with what diligent examination the rules of depth and distance have been tested, that if more attention had been paid to the source of injury, and to the mode of securing an effective and permanent discharge of the injurious water, much greater service would be done."
In conclusion, as to distances, we should advise great caution on the part of beginners in laying out their drains. Draining is too expensive a work to be carelessly or unskillfully done. A mistake in locating drains too far apart, brings a failure to accomplish the end in view. A mistake in placing them too near, involves a great loss of labor and money. Consult, then, those whose experience has given them knowledge, and pay to a professional engineer, or some other skillful person, a small amount for aid, which will probably save ten times as much in the end. We have placed our own drains in porous, though very wet soil, at fifty feet distances, which, in most soils, might be considered extremely wide. We are fully satisfied that they would have drained the land as well at sixty feet, except in a few low places, where they could not be sunk four feet for want of fall.
In most New England lands that require drainage, we believe that from 40 to 50 feet distances, with four feet depth, will prove sufficient. Upon stiff clays, we have no experience of our own of any value, although we have a field of the stiffest clay, drained last season at 40 feet distances and four feet depth. In England, this would, probably, prove insufficient, and, perhaps, it will prove so here. One thing is certain, that, at present, there is little land in this country that will pay for drainage by hand labor, at the English distances in clay, of 16 or 20 feet. If our powerful Summer's sun will not somehow compensate in part for distance, we must, upon our clays, await the coming of draining plows and steam.
DEPTH OF DRAINS.
Cheap and temporary expedients in agriculture are the characteristics of us Americans, who have abundance of land, a whole continent to cultivate, and comparatively few hands and small capital with which to do the work. We erect temporary houses and barns and fences, hoping to find time and means at a future day, to reconstruct them in a more thorough manner. We half cultivate our new lands, because land is cheaper than labor; and it pays best for the present, rather to rob our mother earth, than to give her labor for bread.
The easy and cheap process in draining, is that into which we naturally fall. It is far easier and cheaper to dig shallow than deep drains, and, therefore, we shall not dig deep unless we see good reason to do so. If, however, we carefully study the subject, it will be manifest that superficial drainage is, in general, the result of superficial knowledge of the subject.
Thorough-drainage does not belong to pioneer farming, nor to a cheap and temporary system. It involves capital and labor, and demands skill and system. It cannot be patched up, like a brush fence, to answer the purpose, from year to year, but every tile must be placed where it will best perform its office for a generation. In England, the rule and the habit in all things, is thoroughness and permanency; yet the first and greatest mistake there in drainage was shallowness, and it has required years of experiments, and millions of money, to correct that mistake. If we commit the same folly, as we are very likely to do, we cannot claim even the originality of the blunder, and shall be guilty of the folly of pursuing the crooked paths of their exploration, instead of the straight highway which they have now established. To be sure, the controversy as to the depth of drains has by no means ceased in England, but the question is reduced to this, whether the least depth shall be three feet or four; one party contending that for certain kinds of clay, a three-foot drain is as effectual as a four-foot drain, and that the least effectual depth should be used, because it is the cheapest; while the general opinion of the best scientific and practical men in the kingdom, has settled down upon four feet as the minimum depth, where the fall and other circumstances render it practicable. At the same time, all admit that, in many cases, a greater depth than four feet is required by true economy. It may seem, at first, that a controversy, as to one additional foot in a system of drainage, depends upon a very small point; but a little reflection will show it to be worthy of careful consideration. Without going here into a nice calculation, it may be stated generally as an established fact, that the excavation of a ditch four feet deep, costs twice as much as that of a ditch three feet deep. Although this may not seem credible to one who has not considered the point, yet it will become more probable on examination, and very clear, when the actual digging is attempted. Ditches for tiles are always opened widest at top, with a gradual narrowing to near the bottom, where they should barely admit the tile. Now, the addition of a foot to the depth, is not, as it would perhaps at first appear, merely the addition of the lowest and narrowest foot, but rather of the topmost and widest foot. In other words, a four-foot ditch is precisely a three-foot ditch in size and form, with an additional foot on the top of it, and not a three-foot ditch deepened an additional foot.
The lowest foot of a four-foot ditch is raised one foot higher, to get it upon the surface, than if the ditch were but three feet deep. In clays, and most other soils, the earth grows harder as we go deeper, and this consideration, in practice, will be found important. Again: the small amount of earth from a three-foot ditch, may lie conveniently on one bank near its edge, while the additional mass from a deeper one must be thrown further; and then is to be added the labor of replacing the additional quantity in filling up.
On the whole, the point may be conceded, that the labor of opening and finishing a four-foot drain is double that of a three-foot drain.
Without stopping here to estimate carefully the cost of excavation and the cost of tiles, it may be remarked, that, upon almost any estimate, the cost of labor, even in a three-foot drain in this country, yet far exceeds the cost of tiles: but, if we call them equal, then, if the additional foot of depth costs as much as the first three feet, we have the cost of a four-foot tile-drain fifty per cent. more than that of a three-foot drain. In other words, 200 rods of four-foot drain will cost just as much as 300 rods of three-foot drain. This is, probably, as nearly accurate as any general estimate that can be made at present. The principles upon which the calculations depend, having been thus suggested, it will not be difficult to vary them so as to apply them to the varying prices of labor and tiles, and to the use of the plow or other implements propelled by animals or steam, when applied to drainage in our country.
The earliest experiments in thorough-drainage, in England, were at very small depths, two feet being, for a time, considered very deep, and large tracts were underlaid with tiles at a depth of eighteen, and even twelve inches. It is said, that 10,000 miles of drains, two feet deep and less, were laid in Scotland before it was found that this depth was not sufficient. Of course, the land thus treated was relieved of much water, and experimenters were often much gratified with their success; but it may be safely said now, that there is no advocate known to the public, in England, for a system of drainage of less than three feet depth, and no one advocates a system of drainage of less than four feet deep, except upon some peculiar clays.
The general principle seems well established, that depth will compensate for width; or, in other words, that the deeper the drain, the farther it will draw. This principle, generally correct, is questioned when applied to peculiar clays only. As to them, all that is claimed is, that it is more economical to make the drains but three feet, because they must, even if deep, be near together—nobody doubting, that if four feet deep or more, and near enough, they will drain the land.
In speaking of clay soil, it should always be borne in mind, that clay is merely a relative term in agriculture. "A clay in Scotland," says Mr. Pusey, "would be a loam in the South of England." Professor Mapes, of our own country, in the Working Farmer, says, "We are convinced, that, with thorough subsoil plowing, no clay soil exists in this country which might not be underdrained to a depth of four feet with advantage."
There can be no doubt, that, with four-foot drains at proper distances, all soils, except some peculiar clays, may be drained, even without reference to the changes produced in the mechanical structure of soil by the operation. There is no doubt, however, that all soils are, by the admission of air, which must always take the place of the water drawn out, and by the percolation of water through them, rendered gradually more porous. Added to this, the subsoil plow, which will be the follower of drainage, will break up the soil to considerable depth, and thus make it more permeable to moisture. But there is still another and more effective aid which Nature affords to the land-drainer, upon what might be otherwise impracticable clays.
This topic deserves a careful and distinct consideration, which it will receive under the title of "Drainage of Stiff Clays."
In discussing the subject of the depth of drains, we are not unmindful of the fact that, in this country, the leaders in the drainage movement, especially Messrs. Delafield, Yeomans, and Johnston, of New York, have achieved their truly striking results, by the use of tiles laid at from two and a half to three feet depth. On the "Premium Farm" of R. J. Swan, of Rose Hill, near Geneva, it is stated that there are sixty-one miles of under-drains, laid from two and a half to three feet deep. That these lands thus drained have been changed in their character, from cold, wet, and unproductive wastes, in many cases, to fertile and productive fields of corn and wheat, sufficiently appears. Indeed, we all know of fields drained only with stone drains two feet deep, that have been reclaimed from wild grasses and rushes into excellent mowing fields. In England and in Scotland, as we have seen, thousands of miles of shallow drains were laid, and were for years quite satisfactory. These facts speak loudly in favor of drainage in general. The fact that shoal drains produce results so striking, is a stumbling-block in the progress of a more thorough system. It may seem like presumption to say to those to whom we are so much indebted for their public spirit, as well as private enterprise, that they have not drained deep enough for the greatest advantage in the end. It would seem that they should know their own farms and their own results better than others. We propose to state, with all fairness, the results of their experiments, and to detract nothing from the credit which is due to the pioneers in a great work.
We cannot, however, against the overwhelming weight of authority, and against the reasons for deeper drainage, which, to us, seem so satisfactory, conclude, that even three feet is, in general, deep enough for under-drains. Three-foot drains will produce striking results on almost any wet lands, but four-foot drains will be more secure and durable, will give wider feeding-grounds to the roots, better filter the percolating water, warm and dry the land earlier in Spring, furnish a larger reservoir for heavy rains, and, indeed, more effectually perform every office of drains.
In reviewing our somewhat minute discussion of this essential point—the proper depth of drains—certain propositions may be laid down with considerable assurance.
TILES MUST BE LAID BELOW THE REACH OF THE SUBSOIL PLOW.
Let no man imagine that he shall never use the subsoil plow; for so surely as he has become already so much alive to improvement, as to thorough-drain, so surely will he next complete the work thus begun, by subsoiling his land.
The subsoil plow follows in the furrow of another plow, and if the forward plow turn a furrow one foot deep, the subsoil may be run two feet more, making three feet in all. Ordinarily, the subsoil plow is run only to the depth of 18 or 20 inches; but if the intention were to run it no deeper than that, it would be liable to dip much deeper occasionally, as it came suddenly upon the soft places above the drains. The tiles should lie far enough below the deepest path of the subsoil plow, not to be at all disturbed by its pressure in passing over the drains. It is by no means improbable that fields that have already been drained in this country, may be, in the lifetime of their present occupants, plowed and subsoiled by means of steam-power, and stirred to as great a depth as shall be found at all desirable. But, in the present mode of using the subsoil plow on land free from stones, a depth less than three and a half or four feet would hardly be safe for the depth of tile-drains.
TILES MUST BE LAID BELOW FROST.
This is a point upon which we must decide for our selves. There is no country where drainage is practiced, where the thermometer sinks, as in almost every Winter it does in New England, to 20 deg. below zero (Fahrenheit).
All writers seem to assume that tile-drains must be injured by frost. What the effect of frost upon them is supposed to be, does not seem very clear. If filled with water, and frozen, they must, of course, burst by the expansion of the water in freezing; but it would probably rarely happen, that drainage-water, running in cold weather, could come from other than deep sources, and it must then be considerably above the freezing point. Still; we know that aqueduct pipes do freeze at considerable depths, though supplied from deep springs. Neither these nor gas-pipes are, in our New England towns, safe below frost, unless laid four feet below the surface; and instances occur where they freeze at a much greater depth, usually, however, under the beaten paths of streets, or in exposed positions, where the snow is blown away. In such places, the earth sometimes freezes solid to the depth of even six feet. It will be suggested at once that our fields, and especially our wet lands, do not freeze so deep, and this is true; but it must be borne in mind, that the very reason why our wet lands do not freeze deeper, may be, that they are filled with the very spring-water which makes them cold in Summer, indeed, but is warmer than the air in Winter, and so keeps out the frost. Drained lands will freeze deeper than undrained lands, and the farmer must be vigilant upon this point, or he may have his work ruined in a single Winter.
We are aware, that upon this, as every other point, ascertained facts may seem strangely to conflict. In the town of Lancaster, among the mountains in the coldest part of New Hampshire, many of the houses and barns of the village are supplied with water brought in aqueducts from the hills. We observed that the logs which form the conduit are, in many places, exposed to view on the surface of the ground, sometimes partly covered with earth, but generally very little protected. There has not been a Winter, perhaps in a half century, when the thermometer has not at times been 10 deg. below Zero, and often it is even lower than that. Upon particular inquiry, we ascertained that very little inconvenience is experienced there from the freezing of the pipes. The water is drawn from deep springs in the mountains, and fills the pipes of from one to two-inch bore, passing usually not more than one or two hundred rods before it is discharged, and its warmth is sufficient, with the help of its usual snow covering, to protect it from the frost.
We have upon our own premises an aqueduct, which supplies a cattle-yard, which has never been covered more than two feet deep, and has never frozen in the nine years of its use. We should not, therefore, apprehend much danger from the freezing of pipes, even at shallow depths, if they carry all the Winter a considerable stream of spring-water; but in pipes which take merely the surface water that passes into them by percolation, we should expect little or no aid from the water in preventing frost. The water filtering downward in Winter must be nearly at the freezing point; and the pipes may be filled with solid ice, by the freezing of a very small quantity as it enters them.
Neither hard-burnt bricks nor hard-burnt tiles will crumble by mere exposure to the Winter weather above ground, though soft bricks or tiles will scarcely endure a single hard frost. Too much stress cannot be laid upon the importance of using hard-burnt tiles only, as the failure of a single tile may work extensive mischief. Writers seem to assume, that the freezing of the ground about the drains will displace the tiles, and so destroy their continuity, and this may be so; though we find no evidence, perhaps, that at three or four feet, there is any disturbance of the soil by freezing. We dig into clay, or into our strong subsoils, and find the earth, at three feet deep, as solid and undisturbed as at twice that depth, and no indication that the frost has touched it, though it has felt the grip of his icy fingers every year since the Flood. With these suggestions for warning and for encouragement, the subject must be left to the sound judgment of the farmer or engineer upon each farm, to make the matter so safe, that the owner need not have an anxious thought, as he wakes in a howling Winter night, lest his drains should be freezing.
Finally, in view of the various considerations that have been, suggested, as well as of the almost uniform authority of the ablest writers and practical men, it is safe to conclude, that, in general, in this country, wherever sufficient outfall can be had, four feet above the top of the tiles should be the minimum depth of drains.
ARRANGEMENT OF DRAINS.
Necessity of System.—What Fall is Necessary.—American Examples.—Outlets.—Wells and Relief-Pipes.—Peep holes.—How to secure Outlets.—Gate to Exclude Back-Water.—Gratings and Screens to keep out Frogs, Snakes, Moles, &c.—Mains, Submains, and Minors, how placed.—Capacity of Pipes.—Mains of Two Tiles.—Junction of Drains.—Effect of Curves and Angles on Currents.—Branch Pipes.—Draining into Wells or Swallow Holes.—Letter from Mr. Denton.
As every act is, or should be, a part of a great plan of life, so every stake that is set, and every line laid in the field, should have relation not only to general principles, but also to some comprehensive plan of operations.
Assuming, then, that the principles advocated in this treatise are adopted as to the details, that the depth preferred is not less than four feet—that the direction preferred is up and down the slope—that the distance apart may range from fifteen to sixty feet, and more in some cases, according to the depth of drains and the nature of the soil—that no tiles smaller than one and a half inch bore will be used, and none less than two inches except for the first one hundred yards, there still remains the application of all these principles to the particular work in hand. With the hope of assisting the deliberations of the farmer on this point, some additional suggestions will be made under appropriate heads.
ARRANGEMENT MUST HAVE REFERENCE TO SYSTEM.
The absolute necessity of some regularity of plan in our work, must be manifest. Without system, we can never, in the outset, estimate the cost of our operation; we can never proportion our tiles to the quantity of water that will pass through them; we can never find the drains afterwards, or form a correct opinion of the cause of any failure that may await us.
We prefer, in general, where practicable, parallel lines for our minor drains, at right angles with the mains, because this is the simplest and most systematic arrangement; but the natural ravines or water-courses in fields, seldom run parallel with each other, or at right angles with the slope of the hills, so that regular work like this, can rarely be accomplished.
If the earth were constructed of regular slopes, or plains of uniform character, we could easily apply to it all our rules; but, broken as it is into hills and valleys, filled with stones here, with a bank of clay there, and a sand-pit close by, we are obliged to sacrifice to general convenience, often, some special abstract rule.
We prefer to run drains up and down the slope; but if the field be filled with undulations, or hills with various slopes, we may often find it expedient, for the sake of system, to vary this course.
If the question were only as to one single drain, we could adjust it so as to conform to our perfect ideal; but as each drain is, as it were, an artery in a complicated system, which must run through and affect every part of it, all must be located with reference to every other, and to the general effect.
Keeping in mind, then, the importance of some regular system that shall include the whole field of operation, the work should be laid out, with as near a conformity to established principles as circumstances will permit.
ARRANGEMENT MUST HAVE REFERENCE TO THE FALL.
In considering what fall is necessary, and what is desirable, we have seen, that although a very slight inclination may carry off water, yet a proportionably larger drain is necessary as the fall decreases, because the water runs slower.
"It is surprising," says Stephens, "what a small descent is required for the flow of water in a well-constructed duct. People frequently complain that they cannot find sufficient fall to carry off the water from the drains. There are few situations where a sufficient fall cannot be found if due pains are exercised. It has been found in practice, that a water-course thirty feet wide and six feet deep, giving a transverse sectional area of one hundred and eighty square feet, will discharge three hundred cubic yards of water per minute, and will flow at the rate of one mile per hour, with a fall of no more than six inches per mile."
Messrs. Shedd and Edson, of Boston, have superintended some drainage works in Milton, Mass., where, after obtaining permission to drain through the land of an adjacent owner, not interested in the operation, they could obtain but three inches fall in one hundred feet, or a half inch to the rod, for three quarters of a mile, and this only by blasting the ledges at the outlet. This fall, however, proves sufficient for perfect drainage, and by their skill, a very unhealthful swamp has been rendered fit for gardens and building-lots. In another instance, in Dorchester, Mass., Mr. Shedd informs us that in one thousand feet, they could obtain only a fall of two inches for their main, and this, by nice adjustment, he expects to make sufficient. In another instance, he has found a fall of two and a half inches in one hundred feet, in an open paved drain to be effectual.
It is certainly advisable always to divide the fall as even as possible throughout the drains, yet this will be found a difficult rule to follow. Very often we have a space of nearly level ground to pass through to our outfall; and, usually, the mains, in order that the minor drains may be carried into them from both sides, must follow up the natural valleys in the field, thus controlling, in a great measure, our choice as to the fall. We are, in fact, often compelled to use the natural fall nearly as we find it.
It is thought advisable to have the mains from three to six inches lower than the drains discharging into them, so that there may be no obstruction in the minor drains by the backing up of water, and the consequent deposition of sand or other obstructing substances. Wherever one stream flows into another, there must be more or less interruption of the course of each. If the water from the minors enters the main with a quick fall, the danger of obstruction in the minor, at least, is much lessened. A frequent cause of partial failure of drains, is their not having been laid with a regular inclination. If, instead of a gradual and uniform fall, there should be a slight rising in the bed of a drain, the descending water will be interrupted there till it accumulate so high as to be above the level of the rising. At this point, therefore, the water must have a tendency to press out of the drains, and will deposit whatever particles of sand or other earthy matter it may bring down.
Drains must, therefore, be so arranged, that in cutting them, their beds may be as nearly as possible, straight, or, at least, have a constant, if not a regular and equal fall.
ARRANGEMENT MUST HAVE REFERENCE TO THE OUTLET.
All agree that it is best to have but few general outlets. "In the whole process of draining," says an engineer of experience, "there is nothing so desirable as permanent and substantial work at the point of discharge." The outlet is the place, of all others, where obstruction is most likely to occur. Everywhere else the work is protected by the earth above it, but here it is exposed to the action of frost, to cattle, to mischievous boys, to reptiles, as well as to the obstructing deposits which are discharged from the drains themselves. In regular work, under the direction of engineers, iron pipes, with swing gratings set in masonry, are used, to protect permanently this important part of the system of drainage.
It may often be convenient to run parallel drains down a slope, bringing each out into an open ditch, or at the bottom of some bank, thus making a separate outlet for each. This practice, however, is strongly deprecated. These numerous outlets cannot be well protected without great cost; they will be forgotten, or, at least, neglected, and the work will fail.
Regarding this point, of few and well-secured outlets, as of great importance, the arrangement of all the drains must have reference to it. When drains are brought down a slope, as just suggested, let them, instead of discharging separately, be crossed, near the foot of the slope, by a sub-main running a little diagonally so as to secure sufficient fall, and so carried into a main, or discharged at a single outlet.
It may be objected, that by thus uniting the whole system, and discharging the water at one point, there may be difficulty in ascertaining by inspection, whether any of the drains are obstructed, or whether all are performing their appropriate work. There is prudence and good sense in this suggestion, and the objection may be obviated by placing wells, or "peep-holes," at proper intervals, in which the flow of the water at various points may be observed. On the subject of wells and peep-holes, the reader will find in another chapter a more particular description of their construction and usefulness.
The position of the outlet must, evidently, be at a point sufficiently low to receive all the water of the field; or, in other words, it must be the lowest point of the work. It will be fortunate, too, if the outlet can be at the same time high enough to be at all times above the back-water of the stream, or pond, or marsh, into which it empties; and high enough, too, to be protected by solid earth about it. In any case, great care should be taken to make the outlet secure and permanent. The process of thorough-drainage is expensive, and will only repay cost, upon the idea that it is permanent—that once well done, it is done forever. The tiles may be expected to operate well, for a lifetime; and the outlet, the only exposed portion of the work, should be constructed to endure as long as the rest.
It is true that this portion of the work may be reached and repaired more conveniently than the tiles themselves; but it must be remembered that the decay of the outlet obstructs the flow of the water, produces a general stagnation throughout the drains, and so may cause their permanent obstruction at various points, hard to be ascertained, and difficult to be reached. Considering our liability to neglect such things as perish by a gradual decay, as well as the many accidental injuries to which the outlet is exposed, there is no security but in a solid and permanent structure at the first.
To illustrate the importance attached to this point in England, as well as to indicate the best mode of securing the outlet, the drawings below have been taken from a pamphlet by Mr. Denton. Fig. 37 represents the mode of constructing the common small outlets of field drainage.
The distinguished engineer, of whose labors we have so freely availed ourselves, remarks as follows upon the subject:
"Too many outlets are objectionable, on account of the labor of their maintenance: too few are objectionable, because they can only exist where there are mains of excessive length. A limit of twenty acres to an outlet, resulting in an average of, perhaps, fourteen acres, will appear, by the practices of the best drainers, to be about the proper thing. If a shilling an acre is reserved for fixing the outlets, which should be iron pipes, with swing gratings, in masonry, very substantial work may be done."
Figures 38 and 39 represent the elevation and section of larger outlets, used in more extensive works.
It is almost essential to the efficiency of drains, that there be fall enough beyond the outlet to allow of the quick flow of the water discharged. At the outlet, must be deposited whatever earth is brought down by the drains; and, in many cases, the outlet must be at a swamp or pond. If no decided fall can be obtained at the outlet, there must be care to provide and keep an open ditch or passage, so that the drainage-water may not be dammed back in the drains. It is advised, even, to follow down the bank of a stream or river, so as to obtain sufficient fall, rather than to have the outlet flooded, or back-water in the drains. Still, there may be cases where it will be impossible to have an outlet that shall be always above the level of the river or pond which may receive the drainage water. If the outlet must be so situated as to be at times overflowed, great care should be taken to excavate a place at the outlet, into which any deposits brought down by the drain, may fall. If the outlet be level with the ground beyond it, the smallest quantity of earth will operate as a dam to keep back the water. Therefore, at the outlet, in such cases, a small well of brick or stonework should be constructed, into which the water should pour. There, even if the water stand above the outlet, will be deposited the earth brought along in the drain. This well must at times, when the water is low, be cleared of its contents, and kept ready for its work.
The effect of back-water in drains cannot ordinarily be injurious, except as it raises the water higher in the land, and occasions deposits of earthy matter, and so obstructs the drains. We have in mind now, the common case of water temporarily raised, by Winter flowage or by Summer freshets.
It should be remembered that even when the outlet is under water, if there is any current in the stream into which the drain empties, there must be some current in the drain also; and even if the drain discharge into a still pond, there must be a current greater or less, as water from a level higher than the surface of the pond, presses into the drains. Generally, then, under the most unfavorable circumstances, we may expect to have some flow of water through the pipes, and rarely an utter stagnation. If, then, the tiles be carefully laid, so as to admit only well-filtered water, there can be but little deposit in the drain; and a temporary stagnation, even, will not injure them, and a trifling flow will keep them clean. Much will depend, as to the obstruction of drains, in this, and indeed in all cases, upon the internal smoothness, and upon the nice adjustment of the pipes. In case of the drainage of marshes, and other lands subject to sudden flood, a flap, or gate, is used to exclude the water of flowage, until counterbalanced by the drainage-water in the pipes.
We are quite sure that it is not in us a work of supererogation to urge upon our farmers the importance of careful attention to this matter of outlets. This is one of that class of things which will never be attended to, if left to be daily watched. We Americans have so much work to do, that we have no time to be careful and watchful. If a child fall into the fire, we take time to snatch him out. If a sheep or ox get mired in a ditch, we leave our other business, and fly to the rescue. Even if the cows break into the corn, all hands of us, men and boys and dogs, leave hoeing or haying, and drive them out. And, by the way, the frequency with which most of us have had occasion to leave important labors to drive back unruly cattle, rendered lawless by neglect of our fences, well illustrates a national characteristic. We are earnest, industrious, and intent on doing. We can look forward to accomplish any labor, however difficult, but lack the conservatism which preserves the fruit of our labors—the "old fogyism" which puts on its spectacles with most careful adjustment, after wiping the glasses for a clear sight, and at stated periods, revises its affairs to see if some screw has not worked loose. A steward on a large estate, or a corporation agent, paid for inspecting and superintending, may be relied upon to examine his drainage works, and maintain them in repair; but no farmer in this country, who labors with his own hands, has time even for this most essential duty. His policy is, to do his work now, while he is intent upon it, and not trust to future watchfulness.
We speak from personal experience in this matter of outfalls. Our first drains ran down into a swamp, and the fall was so slight, that the mains were laid as low as possible, so that at every freshet they are overflowed. We have many times, each season, been compelled to go down, with spade and hoe, and clear away the mud which has been trodden up by cattle around the outlet. Although a small river flows through the pasture, the cows find amusement, or better water, about these drains, and keep us in constant apprehension of a total obstruction of our works. We propose to relieve ourself of this care, by connecting the drains together, and building one or more reliable outlets.
GRATINGS OR SCREENS AT THE OUTLET.
There are many species of "vermin," both "creeping things" and "slimy things, that crawl with legs," which seem to imagine that drains are constructed for their especial accommodations. In dry times, it is a favorite amusement of moles and mice and snakes, to explore the devious passages thus fitted up for them, and entering at the capacious open front door, they never suspect that the spacious corridors lead to no apartments, that their accommodations, as they progress, grow "fine by degrees and beautifully less," and that these are houses with no back doors, or even convenient places for turning about for a retreat. Unlike the road to Hades, the descent to which is easy, here the ascent is inviting; though, alike in both cases, "revocare gradum, hoc opus hic labor est." They persevere upward and onward till they come, in more senses than one, to "an untimely end." Perhaps stuck fast in a small pipe tile, they die a nightmare death; or, perhaps overtaken by a shower, of the effect of which, in their ignorance of the scientific principles of drainage, they had no conception, they are drowned before they have time for deliverance from the straight in which they find themselves, and so are left, as the poet strikingly expresses it, "to lie in cold obstruction and to rot."
In cold weather, water from the drains is warmer than the open ditch, and the poor frogs, reluctant to submit to the law of Nature which requires them to seek refuge in mud and oblivious sleep, in Winter, gather round the outfalls, as they do about springs, to bask in the warmth of the running water. If the flow is small, they leap up into the pipe, and follow its course upward. In Summer, the drains furnish for them a cool and shady retreat from the mid-day sun, and they may be seen in single file by scores, at the approach of an intruding footstep, scrambling up the pipe. Dying in this way, affects these creatures, as "sighing and grief" did Falstaff, "blows them up like a bladder;" and, like Sampson, they do more mischief in their death, than in all their life together. They swell up, and stop the water entirely, or partially dam it, so that the effect of the work is impaired.
To prevent injuries from this source, there should be, at every outlet, a grating or screen of cast iron, or of copper wire, to prevent the intrusion of vermin. The screen should be movable, so that any accumulation in the pipe may be removed. An arrangement of this kind is shown in Fig. 40, as used in England. We know of nothing of the kind used in this country. For ourself, we have made of coarse wire-netting, a screen, which is attached to the pipe by hinges of wire. Holes may be bored with a bit through even a hard tile, or a No. 9 wire may be twisted firmly round the end of it, and the screen thus secured.
This has thus far, been our own poor and unsatisfactory mode of protecting our drains. It is only better than none, but it is not permanent, and we hope to see some successful invention that may supply this want. So far as we have observed, no such precaution is used in this country; and in England, farmers and others who take charge of their own drainage works, often run their pipes into the mud in an open ditch, and trust the water to force its own passage.
OF WELLS AND RELIEF PIPES.
In draining large tracts of land of uniform surface, it is often convenient to have single mains, or even minors, of great length. Obstructions are liable to occur from various causes: and, moreover, there is great satisfaction in being certain that all is going right, and in watching the operation of our subterranean works. It is a common practice, and to be commended, to so construct our drains, that they may be inspected at suspicious points, and that so we may know their real condition.
For this purpose, wells, or traps, are introduced at suitable points, into which the drains discharge, and from which the water proceeds again along its course.
These are made of iron, or of stone or brick work, of any size that may be thought convenient, secured by covers that may be removed at pleasure.
Where there is danger of obstruction below the wells, relief pipes may be introduced, or the wells may overflow, and so discharge temporarily, the drainage water. These wells, sometimes called silt basins, or traps, are frequently used in road drainage, or in sewers where large deposits are made by the drainage water. The sediment is carried along and deposited in the traps, while the water flows past.
These traps are large enough for a man to enter, and are occasionally cleared of their contents.
When good stone, or common brick, are at hand, occasional wells may be easily constructed. Plank or timber might be used; and we have even seen an oil cask made to serve the purpose temporarily. In most parts of New England, solid iron castings would not be expensive.
The water of thorough-drainage is usually as pure as spring-water, and such wells may often be conveniently used as places for procuring water for both man and beast, a consideration well worth a place in arrangements so permanent as those for drainage.
The following figures represent very perfect arrangements of this kind, in actual use.
The flap attached to a chain at A, is designed to close the incoming drain, so as to keep back the water, and thus flush the drain, as it is termed, by filling it with water, and then suddenly releasing it. It is found that by this process, obstructions by sand, and by per-oxide of iron, may be brought down from the drains, when the flow is usually feeble.
SMALL WELLS, OR PEEP-HOLES.
By the significant, though not very elegant name of peep-holes, are meant openings at junctions, or other convenient points, for watching the pulsations of our subterranean arteries.
In addition to the large structures of wells and traps, such as have been represented, we need small and cheap arrangements, by which we may satisfy ourselves and our questioning friends and neighbors, that every part of our buried treasure, is steadily earning its usury. It is really gratifying to be able to allow those who "don't see how water can get into the tiles," and who inquire so distrustfully whether you "don't think that land on the hill would be just as dry without the drains," to satisfy themselves, by actually seeing, that there is a liberal flow through all the pipes, even in the now dry soil. And then, again,
"The best laid schemes o' mice an' men Gang aft agley."
and drains will get obstructed, by one or other of the various means suggested in another place. It is then convenient to be able to ascertain with certainty, and at once, the locality of the difficulty, and this may be done by means of peep-holes.
These may be formed of cast iron, or of well-burnt clay, or what is called stone-ware, of 4, 6, or 10 inches internal diameter, and long enough to reach from the bottom of the drain to the surface, or a little above it.
The drain or drains, coming into this little well, should enter a few inches above the pipe which carries off the water, so that the incoming stream may be plainly seen. A strong cover should be fitted to the top, and secured so as not to cause injury to cattle at work or feeding on the land. The arrangement will be at once seen by a sketch given on the following page.
In our own fields, we have adopted several expedients to attain this object of convenient inspection. In one case, where we have a sub-main, which receives the small drains of an acre of orchard, laid at nearly five feet depth, we sunk two 40-gallon oil casks, one upon the other, at the junction of this sub-main with another, and fitted upon the top a strong wooden cover. The objections to this contrivance are, that it is temporary; that it occupies too much room; and that it is more expensive than a well of cast iron or stone-ware of proper size.
In another part of the same field, we had a spring of excellent water, where, "from the time whereof the memory of man runneth not to the contrary," people had fancied they found better water to drink, than anywhere else. It is near a ravine, through which a main drain is located, and which is now graded up into convenient plow land.
To preserve this spring for use in the Summer time, we procured a tin-worker to make a well, of galvanized iron, five feet long and ten inches diameter, into which are conducted the drain and the spring. A friendly hand has sketched it for us very accurately; thus:
The spring is brought in at a by a few tiles laid into the bank where the water naturally bursts out. The pipe b brings in the drain, which always flows largely, and the pipe c carries away the water. The small dipper, marked d, hangs inside the well, and is used by every man, woman, and boy, who passes that way. The spring enters six inches above the drain, for convenience in catching its water to drink.
By careful observation the present Winter of 1858-9, the impression that there is some peculiar quality in this water is confirmed, for it is ascertained that it is six degrees warmer in cold weather than any other water upon the farm. The spring preserves a temperature of about 47 deg., while the drain running through the same well, and the other drains in the field, and the well at the house, vary from 39 deg. to 42 deg..
We confess to the weakness of taking great satisfaction in sipping this water, cool in Summer and warm in Winter, and in watching the mingled streams of spring and drainage water, and listening as we pass by, to their tinkling sound, which, like the faithful watchman of the night, proclaims that "all is well."
POSITION AND SIZE OF THE MAINS.
Having fixed on the proper position of the outlet, for the whole, or any portion of our work, the next consideration is the location of the drains that shall discharge at that point. It is convenient to speak of the different drains as mains, sub-mains, and minors. By mains, are understood the principal drains, of whatever material, the office of which is, to receive and carry away water collected by other drains from the soil. By minors, are intended the small drains which receive the surplus water directly from the soil. By sub-mains, are meant such intermediate drains as are frequently in large fields, interposed across the line of the minors, to receive their discharge, and conduct their water to the mains.
They are principally used, where there is a greater length of small drains in one direction than it is thought expedient to use; or where, from the unequal surface, it is necessary to lay out subordinate systems of drains, to reach particular localities.
Whether after the outlet is located, the mains or minors should next be laid out, is not perhaps very important. The natural course would seem to be, to lay out the mains according to the surface formation of the land, through the principal hollows of the field, although we have high authority for commencing with the minors, and allowing their appropriate direction to determine the location of the mains.
This is, however, rather a question of precedence and etiquette, than of practical importance. The only safe mode of executing so important a work as drainage, is by careful surveys by persons of sufficient skill, to lay out the whole field of operations, before the ground is broken; to take all the levels; to compare all the different slopes; consider all the circumstances, and arrange the work as a systematic whole. Generally, there will be no conflict of circumstances, as to where the mains shall be located. They must be lower than the minors, because they receive their water. They must ordinarily run across the direction of the minors, either at right angles or diagonally, because otherwise they cannot receive their discharge. If, then, in general, the minors, as we assume, run down the slope, the mains must run at the foot of the slope and across it.
It will be found in practice, that all the circumstances alluded to, will combine to locate the mains across the foot of regular slopes; and whether in straight or curved lines, along through the natural valleys of the field.
In locating the mains, regard must always be had to the quantity of water and to the fall. Where a field is of regular slope, and the descent very slight, it will be necessary, in order to gain for the main the requisite fall, to run it diagonally across the bottom of the slope, thus taking into it a portion of the fall of the slope. If the fall requires to be still more increased, often the main may be deepened towards the outlet, so as to gain fall sufficient, even on level ground.
If the fall is very slight, the size of the main may be made to compensate in part for want of fall, for it will not be forgotten, that the capacity of a pipe to convey water depends much on the velocity of the current, and the velocity increases in proportion to the fall. If the fall and consequent velocity be small, the water will require a larger drain to carry it freely along. The size of the mains should be sufficient to convey, with such fall as is attainable, the greatest quantity of water that may ever be expected to reach them. Beyond this, an increase of size is rather a disadvantage than otherwise, because a small flow of water runs with more velocity when compressed in a narrow channel, than when broadly spread, and so has more power to force its way, and carry before it obstructing substances.
We have seen, in considering the size of tiles, that in laying the minor drains, their capacity to carry all the water that may reach them is not the only limit of their size. A one-inch tile might in many cases be sufficient to conduct the water; but the best drainers, after much controversy on the point, now all agree that this is a size too small for prudent use, because so small an opening is liable to be obstructed by a very slight deposit from the water, or by a slight displacement, and because the joints furnish small space for the admission of water.
Mains, however, being designed merely to carry off such water as they may receive from other drains, may in general be limited to the size sufficient to convey such water, at the greatest flow. It might seem a natural course, to proportion the capacity of the main to the capacity of the smaller drains that fall into it; and this would be the true rule, were the small drains expected to run full.
If our smallest drain, however, be of two-inch, or even one and a half inch bore, it can hardly be expected to fill at any time, unless of great length, or in some peculiarly wet place. Considering, then, what quantity of water will be likely to be conducted into the main, proportion the main not to the capacity of all the smaller drains leading into it, but to the probable maximum flow—not to what they might bring into it, but to what they will bring.
If the mains be of three-inch pipes, other things being equal, their capacity is nine times that of a one-inch pipe, and two and a quarter times the capacity of a two-inch pipe.
A three-inch main may, then, with equal fall and directness, be safely relied on to carry nine streams of water equal each to one inch diameter, or two and a quarter streams, equal to a two-inch stream. The three-inch main will, in fact, from the less amount of friction, carry much more than this proportion.
The allowance to be made for a less fall in the mains, has already been adverted to, and must not be overlooked. It is believed that the capacity of a three or four-inch pipe to convey water, is in general likely to be much under-estimated.
It is a common error, to imagine that some large stone water-course must be necessary to carry off so large a flow as will be collected by a system over a ten or twenty-acre field. Any one, however, who has watched the full flow of even a three-inch pipe, and observed the water after it has fallen into a nearly level ditch, will be aware, that what seems in the ditch a large stream, impeded as it is by a rough, uneven bottom, may pass through a three inch opening of smooth, well-jointed pipes. When we consider that a four-inch pipe is four times as capacious as a two-inch pipe, and sixteen times as large as a one-inch pipe, we may see that we may accommodate any quantity of water that may be likely anywhere to be collected by drainage, without recourse to other materials than tiles.
When one three or four-inch pipe is not sufficient to convey the water, mains may conveniently be formed of two or more tiles of any form. A main drain is sometimes formed by combining two horse-shoe tiles, with a tile sole or slate between them, to prevent slipping, as in fig. 47.
The combinations represented in the above figures, will furnish sufficient suggestions to enable any one to select or arrange such forms as may be deemed best suited to the case in hand. Where the largest obtainable tile is not large enough, two or more lines of pipes may be laid abreast.
POSITION OF THE MINOR DRAINS.
Assuming that it is desirable to run the small drains, as far as practicable, up and down the slope, the following directions, from the Cyclopedia of Agriculture, are given:
"There is a very simple mode of laying out these (the minor drains), which will apply to most cases, or, indeed, to all, although in some its application may be more difficult. The surface of each field must be regarded as being made up of one or more planes, as the case may be, for each of which the drains should be laid out separately. Level lines are to be set out, a little below the upper edge of each of these planes, and the drains must be then made to cross these lines at right angles. By this means, the drains will run in the line of the greatest slope, no matter how distorted the surface of the field may be."
Much is said, in the English books, about "furrows," and the "direction of the furrows," in connection with the laying out of drains. Much of the land in England, especially in moist places, was formerly laid up by repeated plowings, into ridges varying in breadth from ten to twenty feet, so as to throw off, readily, the water from the surface.
These ridges were sometimes so high, that two boys in opposite furrows, between the ridges, could not see each other. In draining lands thus ridged, it is found far more easy to cut the ditches in the furrows, rather than across or upon the ridges. After thorough-drainage, in most localities, these ridges and furrows are dispensed with. The fact is, probably, only important here, as explaining the constant reference by English writers to this mode of working the land.
Whether we shall drain "down the furrows," or "across the ridges," is not likely to be inquired of, by Americans.
The accompanying diagram represents a field of about thirty acres, as drained by the owner, B. F. Nourse, Esq., of Orrington, Me., a particular description of which will be found in another place.
The curves of the ends of the minors, at their junction with the mains, will indicate their course—the minors curving always so as to more nearly coincide, in course, with the current of water in the mains.
THE JUNCTION OF DRAINS.
Much difficulty arises in practice, as to connecting, in a secure and satisfactory manner, the smaller with the larger drains. It has already been suggested, that the streams should not meet at right angles, but that a bend should be made in the smaller drain, a few feet before it enters the main, so as to introduce the water of the small drain in the direction of the current in the main. In another place, an instance is given where it was found that a quantity of water was discharged with a turn, or junction with a gentle curve, in 100 seconds, that required 140 seconds with a turn at right angles; and that while running direct, that is, without any turn, it was discharged in 90 seconds. This is given as a mere illustration of the principle, which is obvious enough. Different experiments would vary with the velocity, quantity of water, and smoothness of the pipe; but nothing is more certain, than that every change of direction impedes velocity.
Thus we see that if we had but a single drain, the necessary turns should be curved, to afford the least obstruction.
Where the drain enters into another current, there is yet a further obstruction, by the meeting of the two streams. Two equal streams, of similar velocity and size, thus meeting at right angles, would have a tendency to move off diagonally, if not confined by the pipe; and, confined as they are, must both be materially retarded in their flow. In whatever manner united, there must be much obstruction, if the main is nearly full, at the point of junction. The common mode of connecting horse-shoe tile-drains is shown thus:
Having no tiles made for the purpose, we, at first, formed the union by means of common hard bricks. Curving down the small drain toward the direction of the main, we left a space between two tiles of the main, of two or three inches, and brought down the last tile of the small drain to this opening, placing under the whole a flat stone, slate, or bricks, or a plank, to keep all firm at the bottom. Then we set bricks on edge on all sides, and covered the space at the top with one or more, as necessary, and secured carefully against sand and the like.
We have since procured branch-pipes to be made at the tile-works, such as are in use in England, and find them much more satisfactory. The branches may be made to join the mains at any angle, and it might be advisable to make this part of both drains larger than the rest, to allow room for the obstructed waters to unite peacefully.
The mains should be from three to six inches deeper than the minors. The fall from one to the other may usually be made most conveniently, by a gradual descent of three or four feet to the point of junction; but with branch-pipes, the fall may be nearly vertical, if desired, by turning the branch upward, to meet the small pipe. It will be necessary, in procuring branches for sole-tiles, to bear in mind that they are "rights and lefts," and must be selected accordingly, as the branch comes in upon the one or other side of the main.
The branch should enter the larger pipe not level with the bottom, but as high as possible, to give an inch fall to the water passing out of the branch into the main, to prevent possible obstruction at the junction.
DRAINAGE INTO WELLS, OR SWALLOW HOLES.
In various parts of our country, there are lands lying too flat for convenient drainage in the ordinary methods, or too remote from any good outlet, or perhaps enclosed by lands of others who will not consent to an outfall through their domain, where the drainage water may be discharged into wells.
In the city of Washington, on Capitol Hill, it is a common practice to drain cellars into what are termed "dry wells." The surface formation is a close red clay, of a few feet thickness, and then comes a stratum of coarse gravel; and the wells for water are sunk often as deep as sixty feet, indicating that the water-table lies very low. The heavy storms and showers fill the surface soil beyond saturation, and the water gushes out, literally, into the cellars and other low places. A dry well, sunk through the clay, conducts this water into the gravel bed, and this carries it away. This idea is often applied to land drainage. It is believed that there are immense tracts of fertile land at the West, upon limestone, where the surface might readily be relieved of surplus water, by conducting the mains into wells dug for the purpose. In some places, there are openings called "sink-holes," caused by the sinking of masses of earth, as in the neighborhood of the city of St. Louis, which would afford outlets for all the water that could be poured into them. In the Report of the Tioga County Agricultural Society for 1857, it is said in the Country Gentleman, that instances are given, where swamps were drained through the clay bottom into the underlying gravelly soil, by digging wells and filling them with stones.
In Fig. 7, at page 82, is shown a "fault" in the stratification of the earth; which faults, it is said, so completely carry off water, that wells cannot be sunk so as to reach it.
Mr. Denton says that in several parts of England, advantage is taken of the natural drainage existing beneath wet clay soils, by concentrating the drains to holes, called "swallow-holes." He says this practice is open to the objection that those holes do not always absorb the water with sufficient rapidity, and so render the drainage for a time, inoperative.
These wells are liable, too, to be obstructed in their operation by their bottoms being puddled with the clay carried into them by the water, and so becoming impervious. This point would require occasional attention, and the removal of such deposits.
This principle of drainage was alluded to at the American Institute, February 14, 1859, by Professor Nash. He states, that there are large tracts of land having clay soil, with sand or gravel beneath the clay, which yet need drainage, and suggests that this may be effected by merely boring frequent holes, and filling them with pebbles, without ditches. In all such soils, if the mode suggested prove insufficient, large wells of proper depth, stoned up, or otherwise protected, might obviously serve as cheap and convenient outlets for a regular system of pipe or stone drains.
Mr. Bergen, at the same meeting, stated that such clayey soil, based on gravel, was the character of much of the land on Long Island; and we cannot doubt that on the prairies of the West, where the wells are frequently of great depth to obtain water for use, wells or swallow-holes to receive it, may often be found useful. Whenever the water-line is twenty or thirty feet below the surface, it is certain that it will require a large amount of water poured in at the surface of a well to keep it filled for any considerable length of time. The same principle that forces water into wells, that is, pressure from a higher source, will allow its passage out when admitted at the top.
We close this chapter with a letter from Mr. Denton. The extract referred to, has been here omitted, because we have already, in the chapter preceding this, given Mr. Denton's views, expressed more fully upon the same subject, with his own illustrations.
It should be stated that the letter was in reply to inquiries upon particular points, which, although disconnected, are all of interest, when touched upon by one whose opinions are so valuable.
"LONDON, 52 Parliament Street, Westminster, S. W.
"MY DEAR SIR:—I have received your letter of the 17th August, and hasten to reply to it.
"I am gratified at the terms in which you speak of my roughly-written 'Essays on Land Drainage.' If you have not seen my published letter to Lord Berners, and my recent essay 'On the Advantages of a Daily Record of Rain-fall,' I should much like you to look over them, for my object in both has been to check the uniformity of treatment which too much prevails with those who are officially called upon to direct draining, and who still treat mixed soils and irregular surfaces pretty much in the same way as homogeneous clays and even surfaces, the only difference being, that the distance between the drains is increased. We have now, without doubt, arrived at that point in the practice of draining in this country, which necessitates a revision of all the principles and rules which have been called into force by the Drainage Acts, and the institution of the Drainage Commission, whose duty it is to administer those Acts, and to protect the interests of Reversioners.
"This protection is, in a great measure, performed by the intervention of 'Inspectors of Drainage,' whose subordinate duty it is to see that the improvements provisionally sanctioned are carried out according to certain implied, if not fixed, rules. This is done by measuring depth and distance, which tends to a parallel system (4 feet deep) in all soils, which was Smith of Deanston's notion, only his drains were shallower, i.e., from 2 to 3 feet deep.
"Some rules were undoubtedly necessary when the Commissioners first commenced dispensing the public money, and I do not express my objection to the absurd position to which these rules are bringing us, from any disrespect to them, nor with an idea that any better course could have been followed by the Government, in the first instance, than the adoption of the 'Parkes—Smith frequent drain system.' This system was correctly applied, and continues to be correctly applied, to absorbent and retentive soils requiring the aeration of frequent drains to counteract their retentive nature; but it is altogether misapplied when adopted in the outcropping surfaces of the free water-bearing strata, which, though equally wet, are frequently drained by a comparatively few drains, at less than half the cost.
"The only circumstance that can excuse the indiscriminate adoption of a parallel system, is the fact, that all drains do some good, and the chances of a cure being greater in proportion to the number of drains, it was not necessary to insist upon that judgment which ten years' experience should now give.
"My views on this point will perhaps be best understood by the following extract from an address I recently delivered. [Extract omitted, see p. 161].
* * * "I use one and a half inch pipes for the upper end of drains (though I prefer two-inch), one half being usually one and a half and the other half two-inch. This for minor drains; the mains run up to 9 or 10 inches, and even 18 inches in size, according to their service.
"There is no doubt sufficient capacity in one-inch pipes for minor drains; but, inasmuch as agricultural laborers are not mathematical scholars, and are apt to lay the pipes without precise junctions, it is best to have the pipes so large as to counteract that degree of carelessness which cannot be prevented. The ordinary price of pipes in this country will run thus: + meaning above, and-below, the prices named:
1-1/2 inch 15s. + 2 " 20s. - 3 " 30s. 4 " 40s. + 5 " 50s. + 6 " 60s. +
"The price of cutting clays 4 feet deep, will vary from 1d. to 1-1/2d. per yard, according to density and mixture with stone; and the price of cutting in mixed soils will vary from 1-1/2d. to 6d., according to the quantity of pick-work and rock, and with respect, also, to the price of agricultural labor. (See my tabular table of cost in Land Drainage and Drainage Systems.)
"I should have thought it would have been quite worth the while of the American Government to have had a farm of about 500 acres, drained by English hands, under an experienced engineer, as a practical sample of English work, for the study of American agriculturists, with every drain laid down on a plan, with the sizes of the pipes, and all details of soil, and prices of labor and material, set forth.
"I am, dear Sir, "Yours very faithfully, "The HON. H. F. FRENCH, Exeter. "J. BAILEY DENTON."
THE COST OF TILES—TILE MACHINES.
Prices far too high; Albany Prices.—Length of Tiles.—Cost in Suffolk Co., England.—Waller's Machine.—Williams' Machine.—Cost of Tiles compared with Bricks.—Mr. Denton's Estimate of Cost.—Other Estimates.—Two-inch Tiles can be Made as Cheaply as Bricks.—Process of Rolling Tiles.—Tile Machines.—Descriptions of Daines'.—Pratt & Bro.'s.
The prices at which tiles are sold is only, as the lawyers say, prima facie evidence of their cost. It seems to us, that the prices at which tiles have thus far been sold in this country, are very far above those at which they may be profitably manufactured, when the business is well understood, and pursued upon a scale large enough to justify the use of the best machinery. The following is a copy of the published prices of tiles at the Albany Tile Works, and the same prices prevail throughout New England, so far as known:
2-1/2 inches rise $12 per 1000. 3-1/2 " " 15 " 4-1/2 " " 18 " 5-1/2 " " 40 " 6-1/2 " " 60 " 7-1/2 " " 75 "
2 inches rise $12 per 1000. 3 " " 18 " 4 " " 40 " 5 " " 60 " 6 " " 80 " 8 " " 125 "
Few round pipe-tiles have yet been used in this country, although they are the kind generally preferred by engineers in England. The prices of round tiles would vary little from those of sole-tiles.
Tiles are usually cut fourteen inches long, and shorten, in drying and burning, to about twelve and a half inches, so that, with breaking and other casualties, they may be calculated to lay about one foot each; that is to say, 1,000 tiles may be expected to lay 1,000 feet of drains.
To assist those who desire to manufacture tiles for sale, or for private use, it is proposed to give such information as has been gathered from various sources as to the cost of making, and the selling prices of tiles, in England. The following is a memorandum made at the residence of Mr. Thomas Crisp, at Butley Abbey, in Suffolk Co., Eng., from information given the author on the 8th of July, 1857:
"Mr. Crisp makes his own tiles, and also supplies his neighbors who need them. He sells one and a half inch pipes at 12s. ($3) per 1,000. He pays 5s. ($1.25) per 1,000 for having them made and burnt. His machine is Waller's patent, No. 22, made by Garrett and Son, Leiston, Saxemundham, Suffolk. It works by a lever, makes five one and a half inch pipes at once, or three sole-tiles about two-inch. The man at work said, that he, with a man to carry away, &c., could make 4,000 one and a half inch pipes per day. They used no screen, but cut the clay with a wire. The machine cost L25 (about $125). At the kiln, which is permanent, the tiles are set on end, and bricks with them in the same kiln. They require less heat than bricks, and cost about half as much as bricks here, which are moulded ten inches by five.
"Two girls were loading bricks into a horse-cart, and two women receiving them, and setting them in the kiln. They made roof-tiles with the same machine, and also moulded large ones by hand. The wages of the women are about 8d. (sixteen cents) per day."
At the exhibition of the Royal Agricultural Society, in England, the author saw Williams' Tile Machine in operation, and was there informed by the exhibitor, who said he was a tile-maker, that it requires five-sevenths as much coal to burn 1,000 two-inch tiles, as 1,000 bricks—the size of bricks being 10 by 5; and he declared, that he, with one boy, could make with the machine, 7,000 two-inch tiles per day, after the clay is prepared. Of course, one other person, at least, must be employed to carry off the tiles.
Mr. Denton gives his estimates of the prices at which pipe-tiles may be procured in England, as follows—the prices, which he gives in English currency, being translated into our own:
"When ordinary agricultural labor is worth $2 50 per week, pipes half one and a half inch, and half two-inch, maybe taken at an average cost of $4 38 per 1,000. When labor is $3 00 per week, the pipes will average $5 00 per 1,000, and when labor is $3 50, they will rise to $5 62."
He adds: "In giving the above average cost of materials, those districts are excluded from consideration, where clay suitable for pipes, exists in the immediate vicinity of coal-pits, which must necessarily reduce the cost of producing them very considerably."
Taking the averages of several careful estimates of the cost of tiles and bricks, from the "Cyclopaedia of Agriculture," we have the price of tiles in England about $5 per 1,000, and the price of bricks $7.87, from which the duty of 5s. 6d. should be deducted, leaving the average price of bricks $6.50. Upon tiles there is no such duty. Bricks in the United States are made of different sizes, varying from 8 x 4 in. to the English standard 10 x 5 in. Perhaps a fair average price for bricks of the latter size, would be not far from $5 per 1,000; certainly below $6.50 per 1,000. There is no reason why tiles may not be manufactured in the United States, as cheaply, compared with the prices of bricks, as in England; and it is quite clear that tiles of the sizes named, are far cheaper there than common bricks.
What is wanted in this country is, first, a demand sufficient to authorize the establishment of works extensive enough to make tiles at the best advantage; next, competent skill to direct and perform the labor; and, finally, the best machinery and fixtures for the purpose. It is confidently predicted, that, whenever the business of tile-making becomes properly established, the ingenuity of American machinists will render it easy to manufacture tiles at English prices, notwithstanding the lower price of labor there; and that we shall be supplied with small tiles in all parts of the country at about the current prices of bricks, or at about one half the present Albany prices of tiles, as given at the head of this chapter. It should be mentioned here, perhaps, that, in England, it is common to burn tiles and bricks together in the same kiln, placing the tiles away from the hottest parts of the furnace; as, being but about half an inch in thickness, they require less heat to burn them than bricks.
In the estimates of labor in making tiles in England, a small item is usually included for "rolling." Round pipes are chiefly used in England. When partly dried, they are taken up on a round stick, and rolled upon a small table, to preserve their exact form. Tiles usually flatten somewhat in drying, which is not of importance in any but round pipes, but those ought to be uniform. By this process of rolling, great exactness of shape, and a great degree of smoothness inside, are preserved.
Drainage with tiles is a new branch of husbandry in America. The cost of tiles is now a great obstacle in prosecuting much work of this kind which land-owners desire to accomplish. The cost of tiles, and so the cost of drainage, depends very much—it may be said, chiefly—upon the perfection of the machinery for tile-making; and here, as almost everywhere else, agriculture and the mechanic arts go hand in hand. Labor is much dearer in America than in Europe, and there is, therefore, more occasion here than there, for applying mechanical power to agriculture. We can have no cheap drainage until we have cheap tiles; and we can have cheap tiles only by having them made with the most perfect machinery, and at the lowest prices at which competing manufacturers, who understand their business, can afford them.
In the preceding remarks on the cost of tiles, may be found estimates, which will satisfy any thinking man that tiles have not yet been sold in America at reasonably low prices.
To give those who may desire to establish tileries, either for public or private supply, information, which cannot readily be obtained without great expense of English books, as to the prices of tile machines, it is now proposed to give some account of the best English machines, and of such American inventions as have been brought to notice.
It is of importance that American machinists and inventors should be apprised of the progress that has been made abroad in perfecting tile machines; because, as the subject attracts attention, the ingenuity of the universal Yankee nation will soon be directed toward the discovery of improvements in all the processes of tile-making. Tiles were made by hand long before tile machines were invented.
A Mr. Read, in the "Royal Agricultural Journal," claims to have used pipe tiles as early as 1795, made by hand, and formed on a round stick. No machine for making tiles is described, before that of Mr. Beart's, in 1840, by which "common tile and sole (not pipes or tubes) were made." This machine, however, was of simple structure, and not adapted to the varieties of tiles now used.
All tile machines seem to operate on the same general principle—that of forcing wet clay, of the consistency of that used in brick-making, through apertures of the desired shape and size. To make the mass thus forced through the aperture, hollow, the hole must have a piece of metal in the centre of it, around which the clay forms, as it is pushed along. This centre piece is kept in position by one or two thin pieces of iron, which of course divide the clay which passes over them, but it unites again as it is forced through the die, and comes out sound, and is then cut off, usually by hand, by means of a small wire, of the required length, about fourteen inches.
Tile machines work either vertically or horizontally. The most primitive machine which came to the author's notice abroad, was one which we saw on our way from London to Mr. Mechi's place. It was a mere upright cylinder, of some two feet height, and perhaps eight inches diameter, in which worked a piston. The clay was thrown into the cylinder, and the piston brought down by means of a brake, like an old-fashioned pump, and a single round pipe-tile forced out at the bottom. The force employed was one man and two boys. One boy screened the clay, by passing through it a wire in various directions, holding the wire by the ends, and cutting through the mass till he had found all the small stones contained in it. The man threw the masses thus prepared, into the cylinder, and put on the brake, and the other boy received the tiles upon a round stick, as they came down through the die at the bottom, and laid them away. The cylinder held clay enough to make several, perhaps twenty, two-inch pipes. The work was going on in a shed without a floor, and upon a liberal estimate, the whole establishment, including shed and machine, could not cost more than fifty dollars. Yet, on this simple plan, tiles were moulded much more rapidly than bricks were made in the same yard, where they were moulded singly, as they usually are in England. It was said that this force could thus mould about 1,800 small tiles per day.
This little machine seems to be the same described by Mr. Parkes as in general use in 1843, in Kent and Suffolk Counties.
Most of the tile machines now in use in England and America, are so constructed, as to force out the tiles upon a horizontal frame-work, about five two-inch, or three three-inch pipes abreast. The box to contain the clay may be upright or horizontal, and the power may be applied to a wheel, by a crank turned by a man, or by horse, steam, or water power, according to the extent of the works.
We saw at the Exhibition of the Royal Agricultural Society, at Salisbury, in England, in July, 1857, the "pipe and tile machine," of W. Williams, of Bedford. It was in operation, for exhibition, and was worked by one man, who said he was a tile maker, and that he and one boy could make with the machine 7,000 two-inch tiles per day, after the clay was prepared in the pug mill. Four tiles were formed at once, by clay passed through four dies, and the box holds clay enough for thirty-two two-inch tiles, so that thirty-two are formed as quickly as they can be removed, and as many more, as soon as the box can be refilled.