Farm drainage Part 19

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 quant.i.ty 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 ill.u.s.tration of the principle, which is obvious enough. Different experiments would vary with the velocity, quant.i.ty 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 r.e.t.a.r.ded 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:

[Ill.u.s.tration: Fig. 50.--JUNCTION OF DRAINS.]

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 s.p.a.ce 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 s.p.a.ce 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.

[Ill.u.s.tration: Fig. 51. BRANCH PIPES.]

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 pa.s.sing 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 coa.r.s.e 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 ma.s.ses 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 Inst.i.tute, 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 pa.s.sage 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 ill.u.s.trations.

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 h.o.m.ogeneous 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 inst.i.tution 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 circ.u.mstance 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 quant.i.ty 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."

CHAPTER IX.

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:

_Horse-shoe Tile--Pieces._

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 "

_Sole-Tile--Pieces._

2 inches rise $12 per 1000.

3 " " 18 "

4 " " 40 "

5 " " 60 "