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DRAINAGE OF LAND

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Originally appearing in Volume V08, Page 473 of the 1911 Encyclopedia Britannica.
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DRAINAGE OF See also:

LAND . The verb " to drain," with its substantives " drain " and " drainage," represents the O. Eng. parallel drains. The former must occupy the lowest See also:part of the natural hollows, and the latter must run in the See also:line of the greatest slope of the ground. In the See also:case of See also:flat land, where a fall is obtained chiefly by increasing the See also:depth of the drains at their See also:lower ends, these lines may be disposed in any direction that is found convenient; but in undulating ground a single See also:field may require several distinct sets of drains lying at different angles, so as to suit its several slopes. When a field is ridged in the line of the greatest ascent of the ground, there is an obvious convenience in adopting the furrows as the site of the drains; but wherever this is not the case the drains must be laid off to suit the See also:contour of the ground, irrespective of the furrows altogether. When parts of a field are flat, and other parts have a considerable acclivity, it is expedient to cut a receiving drain near to the bottom of the slopes, and to give the flat ground an See also:independent set of drains. In laying off receiving drains it is essential to give hedgerows and trees a See also:good offing, lest the conduit be obstructed by the roots. When a See also:main drain is so placed that parallel ones empty into it from both sides, care should be taken that the inlets of the latter are not made exactly opposite to each other. Much of the success of draining depends on the skilful planning of these main drains, and in making them large enough to See also:discharge the greatest flow of See also:water to which they may be exposed. Very See also:long main drains are to be avoided.

Numerous outlets are also objectionable, from their liability to obstruction. An outlet to an See also:

area of from ro to 15 acres is a good arrangement. These outlets should be faced with See also:mason See also:work, and guarded with See also:iron gratings. The distance and depth apart of the parallel drains is deter-See also:mined chiefly by reference to the texture of the See also:soil. In an impervious See also:clay the flow of the water is much impeded and the water-table can be controlled only by frequent lines of pipes. On such land it is customary to See also:lay them about 3 ft. from the See also:surface and from 15 to 21 ft. apart. In lighter soils the depth, and proportionately the distance apart, is increased, but the drains are rarely more than 4 ft. 6 in. below the surface, though they may be 75 or 100 apart. A fall of at least r in 200 is desirable. There are various forms of under-drainage, some of them alluded to in the See also:historical See also:section below, but by far the commonest is by means of cylindrical or See also:oval pipes of burnt clay about 1 ft. in length, sometimes supplemented by collars, though nowadays the use of these is being abandoned. Pipes vary in See also:bore from 2 in. for the parallel to 6 in. for the main drains. In constructing a drain, it is of importance that the bottom be cut out just wide enough to admit the pipes and no more.

Pipes, when accurately fitted in, are much less liable to derangement than when laid in the bottom of a See also:

trench several times their width, into which a See also:mass of loose See also:earth must necessarily be returned. This is easily effected in the case of soils tolerably See also:free from stones by the use of draining spades and the See also:tile-See also:hook which are represented in the accompanying cut. The tile-hook is an See also:implement by means of which the pipes may be lowered from the edge of the trench and laid at the bottom. An implement, sometimes propelled by See also:steam, known as the draining plough, can be used for opening the trenches. Draining can be carried on at all seasons, but is usually best done in autumn or summer. A thoroughly trustworthy and experienced workman should be selected to lay the pipes, with instructions to set no pipes until he is satisfied that the depth of the drains and level of the bottoms are correct. The expense of tile-drainage may vary from about £2:See also:ros. per See also:acre on See also:locse soils to £10 an acre on the most tenacious soils, the See also:rate of See also:wages and the cost of the pipes, the depth of the trenches and the ease with which they can be dug, all influencing the cost of the See also:process. Drainage is not a See also:modern See also:discovery. The See also:Romans were careful to keep their arable lands dry by means of open trenches or covered drains filled with stones or twigs. It is at least several centuries since covered channels of various kinds were used by See also:British husbandmen for drying their land. See also:Walter Blith (see See also:AGRICULTURE) about the See also:middle of the 17th See also:century wrote ofthe improvement which might be effected in barren land by freeing it from the excess of stagnant water on or near the surface by means of channels filled with faggots or stones, but his principles, never generally adopted, were ultimately forgotten. In the latter See also:half of the 18th century.

See also:

Joseph See also:Elkington, a See also:Warwickshire See also:farmer, discovered a See also:plan of laying dry sloping ground that is drowned by the outbursting of springs. When the higher-lying portion of such land is porous, See also:rain falling upon it sinks down until it is arrested by clay or other impervious See also:matter, which causes it again to issue at the surface and wet the lower-lying ground. Elkington showed that by cutting a deep drain through the clay, aided when necessary by See also:wells or See also:auger holes, the subjacent See also:bed of See also:sand or See also:gravel in which a See also:body of water is pent up by the clay, as in a See also:vessel, might be tapped and the water conveyed harmlessly in the covered drain to the nearest ditch or stream. In the circumstances to which it is applicable, and in the hands of skilful drainers, Elkington's Draining Implements. plan, known as " sink-hole drainage," by bringing into See also:play the natural drainage furnished by porous strata, is often eminently successful. During the subsequent See also:thirty or See also:forty years most of the draining that took See also:place was on this See also:system, and an immense See also:capital was expended in such See also:works with varying results. Things continued in this position until about 1823, when See also:James See also:Smith of Deanston, having discovered anew those principles of draining so long before indicated by Blith, proceeded to exemplify them in his own practice,'and to expound them to the public in a way that speedily effected a See also:complete revolution in the See also:art of draining, and marked an era in agricultural progress. Instead of persisting in fruitless attempts to dry extensive areas by a few dexterous cuts, he insisted on the See also:necessity of providing every field that needed draining at all with a complete system of parallel under-ground channels, See also:running in the line of the greatest slope of the ground, and so near to each other that the whole rain falling at any See also:time upon the surface should sink down and be carried off by the drains. A main receiving drain was to be carried along the lowest part of the ground, with sub-drains in every subordinate hollow that the ground presented. The distances between drains he showed must be regulated by the greater or less retentiveness of the ground operated upon, and gave 10 to 40 ft. as the limits of their distance apart. The depth which he prescribed for his parallel drains was 30 in., and these were to be filled with 12 in. of stones small enough to pass through a 3-in. ring—in See also:short a new edition of Blith's drain. See also:Josiah See also:Parkes, engineer to the Royal Agricultural Society, advocated a greater distance apart for the drains, and, in See also:order that the subterranean water might be reached, a depth of at least 4 ft.

The cultivated lands of See also:

Britain being disposed in ridges which usually See also:lie in the line of greatest ascent, it became customary to See also:form the drains in each furrow, or in each alternate, or third or See also:fourth one, as the case might require, or views of See also:economy dictate and hence the system soon came to be popularly called " furrow draining." From the number and arrangement of the drains, the terms " frequent " and " parallel " were also applied to it. Smith himself more appropriately named it, from its effects, " thorough draining." The See also:sound principles thus promulgated by him were speedily adopted and extensively carried into practice. The See also:great labour and cost incurred in procuring stones in adequate quantities, and the difficulty of carting them in wet seasons, soon led to the substitution of " tiles," and soles of burnt earthenware. The limited See also:supply and high See also:price of these tiles for a time impeded the progress of the new system of draining; but the invention of tile-making See also:machines removed this impediment, and gave a stimulus to this fundamental agricultural improvement. The substitution of cylindrical pipes for the See also:original See also:horse-See also:shoe tiles has still further lowered the cost and increased the efficiency and permanency of drainage works. The system introduced by Smith of Deanston has now been virtually adopted by all drainers. See also:Variations in matters of detail (having respect chiefly to the depth and distance apart of the parallel drains) have indeed been introduced; but the distinctive features of his system are recognized and acted upon. A great stimulus was given to. the improvement of land by the passing in See also:England of a See also:series of acts of See also:parliament, which removed certain obstacles that effectually hindered tenants with limited interests from investing capital in works of drainage and kindred amelioration. The Public See also:Money Drainage Acts 1846–1856 authorized the advance of public money to landowners to enable them to make improvements in their lands, not only by draining, but by See also:irrigation, the making of permanent roads, clearing, erecting buildings, planting for shelter, &c. The rapid absorption of the funds provided by these acts led to further legislative See also:measures by which private capital was rendered available for the improvement of land. A series of See also:special improvement acts were passed, authorizing companies to execute or advance money for executing improvements in land. Finally, the Land Improvement See also:Act 1864, amended and extended by the act of 1899, gave facilities for borrowing money by charging the cost of draining, &c., as a See also:rent-See also:charge upon the See also:inheritance of the land.

The instalments must be repaid with See also:

interest in equal amounts extending over a fixed See also:term of years by the See also:tenant for See also:life during his lifetime, the tenant being See also:bound to maintain the improvements. See C. G. See also:Elliott, See also:Engineering for Land Drainage (New See also:York, 1903); F. H. See also:King, Irrigation and Drainage (New York, 1899); G. S. See also:Mitchell, Handbook of Land Drainage (See also:London, 1898), with a good bibliography.

End of Article: DRAINAGE OF LAND

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