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these will act as silt-basins. During the first few storms the water will flow elf much‘more freely from the first barrel; but, little by little, the second one, as the water finds its way through the clay, and as the occasional drying and repeated filtration make it more porous, will increase in its flow until it will, by the end of the season, or, at latest, by the end of the second season, drain as well as the first, if, indeed, that be not by this time somewhat obstructed with silt. The amount of accumulation in the vessels at the outlet will show which process has best kept back the silt, and the character of the deposit will show which would most probably be carried ofi' by _ the gentle flow of water in a nearly level drain.
It is no argument against this experiment that its results cannot be determined even in a year, for it is not pretended that drains laid in compact clay will dry land so completely during the first month as those which give more free access to the water; only that they will do so in a comparatively short time ; and that, a drainage is a work for all time, (practically as lasting as the farm itselfi) the importance of permanence and good working for long years to come, is out of all proportion to that of the temporary good results of one or two seasons, accompanied with doubtful durability.
It has been argued that smface water will be more readily removed by drains having porous filling. Even if this were true to any important degree,—which it is not,— it would be an argument against the plan, for the remedy would be worse than the disease. If the water flow from the surface down into the drain, it will not fail to carry dirt with it, and instead of the clear water, which alone should rise into the tiles from below, we should have a trickling flow from above, muddy with wasted manure and silty earth.
The remaining filling of the ditch. is a matter of sim~ ple labor, and may be done in whatever way may be most
economical under the circumstances of the work. If the amount to be filled is considerable, so that it is desirable to use horse-power, the best way will be to use a scraper, such as is represented in Figure 39, which is a strongly ironed plank, 6 feet long and 18 inches wide, sharp shod at one side, and supplied with handles at the other. It is propelled by means of the curved rods, which are attached to its under side by flexible joints. These rods are connected by a chain which has links large enough to
receive the hook of an ox-chain. This scraper may be used for any straight-forward work by attaching the power to the middle of the chain. By moving the hook a few links to the right or left, it will act somewhat after the manner of the mould-board of a plow, and will, if skillfully handled, shoot the filling rapidly into the ditch.
If the work is done by hand, mix the surface soil and turf with the subsoil filling for the whole depth. If with a scraper, put the surface soil at the bottom of the loose filling, and the subsoil at the top, as this will be an imitation, for the limited area of the drains, of the process of “ trenching,” which is used in garden cultivation.
When the ditches are filled, they will be higher than the adjoining land, and it will be well to make them still more so by digging or plowing out a small trench at each side of the drain, throwing the earth against the mound, which will prevent surface water, (during heavy rains,) from running into the loose filling before it is sufficiently settled. A cross section of a filled drain provided with these ditches is shown in Figure 40.
In order that the silt-basins may be examined, and their accumulations of earth removed, during the early action of the drains, those parts " . of the ditches which are over 77% them may be left open, care I being taken, by cutting snr”‘ face ditches around them, to prevent the entrance of water ,7 ~ from above.‘ During this time the covers of the basins should be kept on, and should be covered \vithinverted sods F. 40_'/ 1' H
I lg. . CROSS SECTION OF t0 keep loose dirt from get- m'rcn (FILLED), wrru FURting into them_ now AT men sins.
Collecting the Water of Springs—The lateral which connects with the main drain, A, (Fig. 20,) at the point m, and which is to take the water of the spring at the head of the brook, should not be opened until the main has been completed and filled in to the silt-basin,—'the brook having, meantime, been carried over the other ditches in wooden troughs. This lateral may now be made in the following way: Dig down to the tile of the main, and carry the lateral ditch back, a distance of ten feet. In the bottom of this, place a wooden trough, at least six feet long, laid at such depth that its channel .shall be on the exact grade required for laying the tiles, and lay long straw, (held down by weights,) lengthwise withingit. Make an opening in the tile of the main and connect the trough with it. The straw will prevent any coarse particles of earth from being carried into the tile, and the flow of the water will be sufficient to carry on to the silt-basin any finer matters. N ow open the ditch to and beyond the spring, digging at least a foot below the grade in its immediate vicinity, and filling to the exact grade with small stones, broken bricks, or other suitable material. Lay the tiles from the upper end of the ditch across the stone Work, and down to the wooden trough. Now spread a sufiicient layer of wood shavings over the stone work to keep the earth from entering it, cover the tiles and fill in the ditch, as before directed, and then remove the straw from the wooden trough and lay tiles in its place. In this way, the water of even a strong spring may be carried into a finished drain without danger. In laying the tile which crosses the stone work, it is well to use full 2anh tiles in the place of collars, leaving the joints of these, and of the 11-inch tiles, (which should join near the middle of the collar tile,) about a quarter of an inch open, to give free entrance to the water.
The stone and tile drainLH, I, is simply dug out to the surface of the rock, if this is not more than two feet below the grade of the upper ends of the laterals with which it connects, and then filled up with loose stones to the line of grade. Ifthe stones are small, so as to form a good bottom for the tiles, they may be laid directly upon it; if not, a bottom for them mayr be made of narrow strips of cheap boards. Before filling, the tiles and stone work should be covered with shavings, and the filling above these should consist of a strong clay, which will remain in place after the shavings rot away.
Amending the Map—When the tiles are laid, and be fore they are covered, all deviations of the lines, as in pass~ , ing around large stones and other obstructions, which may have prevented the exact execution ofthe original plan, and the location and kind of each underground silt-basin should also be carefully noted, so that they may be transferred to the map, for future reference, in the event of re pairs becoming necessary. In a short time after the work
is finished, the surface of the field will show no trace of the lines of drain, and it should be possible, in case of need, to find any point of the drains with precision, so that no labor will be lost in digging for it. It is much cheaper to measure over the surface than to dig a four foot trench through the ground.
Nora—(Third edition.) All that is said in the former chapter on the subject of silt basins, should be heeded only as modified by what is said on the same subject in Chapter XII and its supplemental note.