Farm drainage / The Principles, Processes, and Effects of Draining Land with Stones, Wood, Plows, and Open Ditches, and Especially with Tiles

by Henry F. French

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.