“ 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 trench several times their width, into which a mass of loose earth must necessarily be returned. This is easily effected in the case of soils tolerably free from stones by the use of draining spades and the tile-hook which are represented in the accompanying cut. ”

“ When the higher-lying portion of such land is porous, rain falling upon it sinks down until it is arrested by clay or other impervious 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 wells or auger holes, the subjacent bed of sand or gravel in which a body of water is pent up by the clay, as in a vessel, might be tapped and the water conveyed harmlessly in the covered drain to the nearest ditch or stream. ”

“ The roots of plants require both air and warmth. A deep stratum through which water can percolate, but in which it can never stagnate, is therefore necessary. A waterlogged soil is impenetrable by air, and owing to the continuous process of evaporation and radiation, its temperature is much below that of drained soil. The surface of the water in the supersaturated soil is known as the “water-table” and is exemplified in water standing in a well. Water will rise in clay by capillarity to a height of 50 in., in sand to 22 in. ”

“ Land is not in a satisfactory condition with respect to drainage unless the rain that falls upon it can sink down to the minimum depth required for the healthy development of the roots of crops and thence find vent either through a naturally porous subsoil or by artificial channels. ”

“ In the case of flat land, where a fall is obtained chiefly by increasing the depth of the drains at their lower ends, these lines may be disposed in any direction that is found convenient; but in undulating ground a single 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 ”

“ A series of special improvement acts were passed, authorizing companies to execute or advance money for executing improvements in land. Finally, the Land Improvement Act 1864, amended and extended by the act of 1899, gave facilities for borrowing money by charging the cost of draining, &c., as a rent-charge upon the inheritance of the land. The instalments must be repaid with interest in equal amounts extending over a fixed term of years by the tenant for life during his lifetime, the tenant being bound to maintain the improvements. ”

“ The tile-hook is an 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 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 £2:10s. per acre on loose soils to £10 an acre on the most tenacious soils, the rate of 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 process.
Drainage is not a modern discovery. The 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 British husbandmen for drying their land. ”

“ 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 independent set of drains. In laying off receiving drains it is essential to give hedgerows and trees a good offing, lest the conduit be obstructed by the roots. ”

“ Very long main drains are to be avoided. Numerous outlets are also objectionable, from their liability to obstruction. An outlet to an area of from 10 to 15 acres is a good arrangement. These outlets should be faced with mason work, and guarded with iron gratings.
The distance and depth apart of the parallel drains is determined chiefly by reference to the texture of the soil. In an impervious 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 lay them about 3 ft. ”