Draining for Profit, and Draining for Health Part 9

Flat Spades of various lengths and widths, Bill-necked Scoop (_A_); Tile-layer (_B_); Pick-axe (_C_); and Scoop Spades, and Shovel.

Writers on drainage, almost without exception, recommend the use of elaborate sets of tools which are intended for cutting very narrow ditches,-only wide enough at the bottom to admit the tile, and not allowing the workmen to stand in the bottom of the ditch. A set of these tools is shown in Fig. 22.

Possibly there may be soils in which these implements, in the hands of men skilled in their use, could be employed with economy, but they are very rare, and it is not believed to be possible, under any circ.u.mstances, to regulate the bottom of the ditch so accurately as is advisable, unless the workman can stand directly upon it, cutting it more smoothly than he could if the point of his tool were a foot or more below the level on which he stands.

On this subject, Mr. J. Bailey Denton, one of the first draining engineers of Great Britain, in a letter to Judge French, says:

"As to tools, it is the same with them as it is with the art of draining itself,-too much rule and too much drawing upon paper; all very right to begin with, but very prejudicial to progress. I employ, as engineer to the General Land Drainage Company, and on my private account, during the drainage season, as many as 2,000 men, and it is an actual fact, that not one of them uses the set of tools figured in print. I have frequently purchased a number of sets of the Birmingham tools, and sent them down on extensive works. The laborers would purchase a few of the smaller tools, such as Nos. 290, 291, and 301, figured in Morton's excellent Cyclopaedia of Agriculture, and would try them, and then order others of the country blacksmith, differing in several respects; less weighty and much less costly, and moreover, much better as working tools. All I require of the cutters, is, that the bottom of the drain should be evenly cut, to fit the size of the pipe. The rest of the work takes care of itself; for a good workman will economize his labor for his own sake, by moving as little earth as practicable; thus, for instance, a first-cla.s.s cutter, in clays, will get down 4 feet with a 12-inch opening, _ordinarily_; if he wishes to _show off_, he will sacrifice his own comfort to appearance, and will do it with a 10-inch opening."

In the Central Park work, sets of these tools were procured, at considerable expense, and every effort was made to compel the men to use them, but it was soon found that, even in the easiest digging, there was a real economy in using, for the first 3 feet of the ditch, the common spade, pick, and shovel,-finis.h.i.+ng the bottoms with the narrow spade and scoop hereafter described, and it is probable that the experience of that work will be sustained by that of the country at large.

*Marking the Lines.*-To lay a drain directly under the position of its stakes, would require that enough earth be left at each point to hold the stake, and that the ditch be tunneled under it. This is expensive and unnecessary. It is better to dig the ditches at one side of the lines of stakes, far enough away for the earth to hold them firmly in their places, but near enough to allow measurements to be taken from the grade pegs. If the ditch be placed always to the right, or always to the left, of the line, and at a uniform distance, the general plan will remain the same, and the lines will be near enough to those marked on the map to be easily found at any future time. In fact, if it be known that the line of tiles is two feet to the right of the position indicated, it will only be necessary, at any time, should it be desired to open an old drain, to measure two feet to the right of the surveyed position to strike the line at once.

In soils of ordinary tenacity, ditches 4 feet deep need not be more than twenty (20) inches wide at the surface, and four (4) inches wide at the bottom. This will allow, in each side, a slope of eight (8) inches, which is sufficient except in very loose soils, and even these may be braced up, if inclined to cave in. There are cases where the soil contains so much running sand, and is so saturated with water, that no precautions will avail to keep up the banks. Ditches in such ground will sometimes fall in, until the excavation reaches a width of 8 or 10 feet. Such instances, however, are very rare, and must be treated as the occasion suggests.

One of the garden lines should be set at a distance of about 6 inches from the row of stakes, and the other at a further distance of 20 inches. If the land is in gra.s.s, the position of these lines may be marked with a spade, and they may be removed at once; but, if it is arable land, it will be best to leave the lines in position until the ditch is excavated to a sufficient depth to mark it clearly. Indeed, it will be well to at once remove all of the sod and surface soil, say to a depth of 6 inches, (throwing this on the same side with the stakes, and back of them.) The whole force can be profitably employed in this work, until all of the ditches to be dug are scored to this depth over the entire tract to be drained, except in swamps which are still too wet for this work.

*Water Courses.*-The brooks which carry the water from the springs should be "jumped" in marking out the lines, as it is desirable that their water be kept in separate channels, so far as possible, until the tiles are ready to receive it, as, if allowed to run in the open ditches, it would undermine the banks and keep the bottom too soft for sound work.

With this object, commence at the southern boundary of our example tract, 10 or 15 feet east of the point of outlet, and drive a straight, temporary, shallow ditch to a point a little west of the intersection of the main line _D_ with its first lateral; then carry it in a northwesterly direction, crossing _C_ midway between the silt-basin and stake _C 1_, and thence into the present line of the brook, turning all of the water into the ditch. A branch of this ditch may be run up between the lines _F_ and _G_ to receive the water from the spring which lies in that direction.

This arrangement will keep the water out of the way until the drains are ready to take it.

*The Outlet.*-The water being all discharged through the new temporary ditch, the old brook, beyond the boundary, should be cleared out to the final level (3.75,) and an excavation made, just within the boundary, sufficient to receive the masonry which is to protect the outlet. A good form of outlet is shown in Fig. 23. It may be cheaply made by any farmer, especially if he have good stone at hand;-if not, brick may be used, laid on a solid foundation of stout planks, which, (being protected from the air and always saturated with water,) will last a very long time.

[Ill.u.s.tration: Fig. 23 - OUTLET, SECURED WITH MASONRY AND GRATING.]

Fig. 23 - OUTLET, SECURED WITH MASONRY AND GRATING.

If made of stone, a solid floor, at least 2 feet square, should be placed at, or below, the level of the brook. If this consist of a single stone, it will be better than if of several smaller pieces. On this, place another layer extending the whole width of the first, but reaching only from its inner edge to its center line, so as to leave a foot in width of the bottom stone to receive the fall of the water. This second layer should reach exactly the grade of the outlet (3.50) or a height of 3 inches from the brook level. On the floor thus made, there should be laid the tiles which are to const.i.tute the outlets of the several drains; _i.e._, one 3-1/2-inch tile for the line from the silt-basin, two 1-1/4-inch for the lines _F_ and _G_, and one 2-1/4-inch for the main line _E_. These tiles should lie close to each other and be firmly cemented together, so that no water can pa.s.s outside of them, and a rubble-work of stone may with advantage be carried up a foot above them. Stone work, which may be rough and uncemented, but should always be solid, may then be built up at the sides, and covered with a secure coping of stone. A floor and sloping sides of stone work, jointed with the previously described work, and well cemented, or laid in strong clay or mortar, may, with benefit, be carried a few feet beyond the outlet. This will effectually prevent the undermining of the structure. After the entire drainage of the field is finished, the earth above these sloping sides, and that back of the coping, should be neatly sloped, and protected by sods. An iron grating, fine enough to prevent the entrance of vermin, placed in front of the tile, at a little distance from them,-and secured by a flat stone set on edge and hollowed out, so as merely to allow the water to flow freely from the drains,-the stone being cemented in its place so as to allow no water to pa.s.s under it,-will give a substantial and permanent finish to the structure.

An outlet finished in this way, at an extra cost of a few dollars, will be most satisfactory, as a lasting means of securing the weakest and most important part of the system of drains. When no precaution of this sort is taken, the water frequently forces a pa.s.sage under the tile for some distance up the drains, undermining and displacing them, and so softening the bottom that it will be difficult, in making repairs, to secure a solid foundation for the work. Usually, repairs of this sort, aside from the annoyance attending them, will cost more than the amount required to make the permanent outlet described above. As well constructed outlets are necessarily rather expensive, as much of the land as possible should be drained to each one that it is necessary to make, by laying main lines which will collect all of the water which can be brought to it.

*The Main Silt-Basin.*-The silt-basin, at which the drains are collected, may best be built before any drains are brought to it, and the work may proceed simultaneously with that at the outlet. It should be so placed that its center will lie exactly under the stake which marks its position, because it will const.i.tute one of the leading landmarks for the survey of the drains.(17)

Before removing the stake and grade stake, mark their position by four stakes, set at a distance from it of 4 or 5 feet, in such positions that two lines, drawn from those which are opposite to each other, will intersect at the point indicated; and place near one of them a grade stake, driven to the exact level of the one to be removed. This being done, dig a well, 4 feet in diameter, to a depth of 2-1/2 feet below the grade of the outlet drain, (in the example under consideration this would be 5 feet below the grade stake.) If much water collects in the hole, widen it, in the direction of the outlet drain, sufficiently to give room for baling out the water. Now build, in this well, a structure 2 feet in interior diameter, such as is shown in Fig. 24, having its bottom 2 feet, in the clear, below the grade of the outlet, and carry its wall a little higher than the general surface of the ground. At the proper height insert, in the brick work, the necessary for tiles all incoming and outgoing drains; in this case, a 3-1/2-inch tile for the outlet, 2-1/4-inch for the mains _A_ and _C_, and 1-1/4-inch for _B_ and _D_.

[Ill.u.s.tration: Fig. 24 - SILT-BASIN, BUILT TO THE SURFACE.]

Fig. 24 - SILT-BASIN, BUILT TO THE SURFACE.

This basin being finished and covered with a flat stone or other suitable material, connect it with the outlet by an open ditch, unless the bottom of the ditch, when laid open to the proper depth, be found to be of muck or quicksand. In such case, it will be best to lay the tile at once, and cover it in for the whole distance, as, on a soft bottom, it would be difficult to lay it well when the full drainage of the field is flowing through the ditch. The tiles should be laid with all care, on a perfectly regulated fall,-using strips of board under them if the bottom is shaky or soft,-as on this line depends the success of all the drains above it, which might be rendered useless by a single badly laid tile at this point, or by any other cause of obstruction to the flow.

While the work is progressing in the field above, there will be a great deal of muddy water and some sticks, gra.s.s, and other rubbish, running from the ditches above the basin, and care must be taken to prevent this drain from becoming choked. A piece of wire cloth, or basket work, placed over the outlet in the basin, will keep out the coa.r.s.er matters, and the mud which would acc.u.mulate in the tile may be removed by occasional flus.h.i.+ng. This is done by crowding a tuft of gra.s.s,-or a bit of sod,-into the lower end of the tile (at the outlet,) securing it there until the water rises in the basin, and then removing it. The rush of water will be sufficient to wash the tile clean.

This plan is not without objections, and, as a rule, it is never well to lay any tiles at the lower end of a drain until all above it is finished; but when a considerable outlet must be secured through soft land, which is inclined to cave in, and to get soft at the bottom, it will save labor to secure the tile in place before much water reaches it, even though it require a daily flus.h.i.+ng to keep it clean.

*Opening the Ditches.*-Thus far it has been sought to secure a permanent outlet, and to connect it by a secure channel, with the silt-basin, which is to collect the water of the different series of drains. The next step is to lay open the ditches for these. It will be best to commence with the main line _A_ and its laterals, as they will take most of the water which now flows through the open brook, and prevent its interference with the rest of the work.

The first work is the opening of the ditches to a depth of about 3 feet, which may be best done with the common spade, pick, and shovel, except that in ground which is tolerably free from stones, a subsoil plow will often take the place of the pick, with much saving of labor. It _may_ be drawn by oxen working in a long yoke, which will allow them to walk one on each side of the ditch, but this is dangerous, as they are liable to disturb the stakes, (especially the grade stakes,) and to break down the edges of the ditches. The best plan is to use a small subsoil plow, drawn by a single horse, or strong mule, trained to walk in the ditch. The beast will soon learn to accommodate himself to his narrow quarters, and will work easily in a ditch 2-1/2 feet deep, having a width of less than afoot at the bottom; of course there must be a way provided for him to come out at each end. Deeper than this there is no economy in using horse power, and even for this depth it will be necessary to use a plow having only one stilt.

[Ill.u.s.tration: Fig. 25 - FINIs.h.i.+NG SPADE.]

Fig. 25 - FINIs.h.i.+NG SPADE.

Before the main line is cut into the open brook, this should be furnished with a wooden trough, which will carry the water across it, so that the ditch shall receive only the filtration from the ground. Those laterals west of the main line, which are crossed by the brook, had better not be opened at present,-not until the water of the spring is admitted to and removed by the drain.

[Ill.u.s.tration: Fig. 26 - FINIs.h.i.+NG SCOOP.]

Fig. 26 - FINIs.h.i.+NG SCOOP.

The other laterals and the whole of the main line, having been cut to a depth of 3 feet, take a finis.h.i.+ng spade, (Fig. 25,) which is only 4 inches wide at its point, and dig to within 2 or 3 inches of the depth marked on the stakes, making the bottom tolerably smooth, with the aid of the finis.h.i.+ng scoop, (Fig. 26,) and giving it as regular an inclination as can be obtained by the eye alone.

[Ill.u.s.tration: Fig. 27 - BRACING THE SIDES IN SOFT LAND.]

Fig. 27 - BRACING THE SIDES IN SOFT LAND.

If the ground is "rotten," and the banks of the ditches incline to cave in, as is often the case in pa.s.sing wet places, the earth which is thrown out in digging must be thrown back sufficiently far from the edge to prevent its weight from increasing the tendency; and the sides of the ditch may be supported by bits of board braced apart as is shown in Fig.

27.

[Ill.u.s.tration: Fig. 28 - MEASURING STAFF.]

Fig. 28 - MEASURING STAFF.

The manner of opening the ditches, which is described above, for the main _A_ and its laterals, will apply to the drains of the whole field and to all similar work.

*Grading the Bottoms.*-The next step in the work is to grade the bottoms of the ditches, so as to afford a bed for the tiles on the exact lines which are indicated by the figures marked on the different stakes.

The manner in which this is to be done may be ill.u.s.trated by describing the work required for the line from *C10* to *C17*, (Fig. 20,) after it has been opened, as described above, to within 2 or 3 inches of the final depth.

A measuring rod, or square, such as is shown in Fig. 28,(18) is set at *C10*, so that the lower side of its arm is at the mark 4.59 on the staff, (or at a little less than 4.6 if it is divided only into feet and tenths,) and is held upright in the ditch, with its arm directly over the grade stake. The earth below it is removed, little by little, until it will touch the top of the stake and the bottom of the ditch at the same time.

If the ground is soft, it should be cut out until a flat stone, a block of wood, or a piece of tile, or of brick, sunk in the bottom, will have its surface at the exact point of measurement. This point is the bottom of the ditch on which the collar of the tile is to lie at that stake. In the same manner the depth is fixed at _C11_ (4.19,) and _C12_ (4.41,) as the rate of fall changes at each of these points, and at _C15_ (3.89,) and _C17_ (4.17,) because (although the fall is uniform from _C12_ to _C17_,) the distance is too great for accurate sighting.

[Ill.u.s.tration: Fig. 29 - BONING ROD.]

Fig. 29 - BONING ROD.

Having provided _boning-rods_, which are strips of board 7 feet long, having horizontal cross pieces at their upper ends, (see Fig. 29,) set these perpendicularly on the spots which have been found by measurement to be at the correct depth opposite stakes 10, 11, 12, 15, and 17, and fasten each in its place by wedging it between two strips of board laid across the ditch, so as to clasp it, securing these in their places by laying stones or earth upon their ends.

As these boning-rods are all exactly 7 feet long, of course, a line sighted across their tops will be exactly 7 feet higher, at all points, than the required grade of the ditch directly beneath it, and if a plumb rod, (similar to the boning-rod, but provided with a line and plummet,) be set perpendicularly on any point of the bottom of the drain, the relation of its cross piece to the line of sight across the tops of the boning-rods will show whether the bottom of the ditch at that point is too high, or too low, or just right. The manner of sighting over two boning-rods and an intermediate plumb-rod, is shown in Fig. 31.

[Ill.u.s.tration: Fig. 30 - POSITION OF WORKMAN AND USE OF FINIs.h.i.+NG SCOOP.]