This section is from the book "Spons' Mechanics' Own Book: A Manual For Handicraftsmen And Amateurs", by Edward Spon. Also available from Amazon: Spons' Mechanics' Own Book.
In making banks, the necessary material is thrown or wheeled into position, and piled up in such a way that it will retain the position given to it. To ensure this it is essential to observe a correct slope. Most materials will lie naturally at an angle not exceeding 40° with the horizon, while 20° or even 10° will suffice if the surface is covered with turf, the binding together of the earth by the roots of the grass preventing the scouring effect which would otherwise be exerted by every shower of rain. When such materials as large stones are available, the bank may assume more the nature of a wall, and be built on one side at least very nearly vertical. The same object may be attained by driving 2 or 3 rows of stakes into the firm ground beneath, and ramming the earth tightly around them; or a sort of hurdle may be made by winding brushwood among the stakes.
Banks are seldom used alone for the purpose of a fence, being usually supplemented by a hedge planted at the top. This is generally of hawthorn, from its impenetrable character, though many other shrubs are available in different regions, for instance fuchsias are so planted in Ireland. The hedge serves a double purpose of great utility in forming a serviceable fence and presenting an obstacle to the wind and a shelter for cattle. On the other hand it harbours vermin. In connection with the hedge and bank, a ditch is needed. This increases the effectiveness of the fence, and drains the roots of the hedge, besides being a ready means of supplying the material required to form the bank. As the hedge and ditch occupy a considerable space of land, it is a pity that some tree or shrub affording a useful product cannot be more generally adopted.
Drains, not to be confounded with sewer pipes, are provided for the purpose of easily and effectively carrying off the excess of water which falls during heavy rain, preventing its lying in a stagnant condition to the detriment of health and vegetation. Obviously this could be accomplished by simple open ditches having the requisite amount of fall, i.e. being cut in such directions as suited the undulation of the surface, in order to accommodate the natural tendency of the water to find the lowest available level. But an open drain is very costly to keep free from weeds and fallen earth, and becomes a receptacle for the best portion of the soil, washed into it by the rushing water. Therefore the first principle in draining is to provide a channel for the water at such a depth beneath the surface as the nature of the ground determines: that is to say, when the subsoil is a stiff clay impervious to moisture, the drain channel should be only so far beneath the surface as to escape all possibility of contact with the plough or spade used in tilling the surface; while in more porous soil the depth may be 3-4 ft.
The first step is to set out the lines which the drains are to follow, choosing the lowest level for the main channel, and letting the others meet it at an angle of about 30°. On these lines trenches are dug with a trenching tool to the requisite depth and with contracting sides. In these trenches a water channel is formed in various ways. In stiff clays, filling the bottom with brushwood and then replacing the surface earth will often be effective for years. But a far more enduring and efficient method is to occupy the lower space with stones in some form. Fig. 1401 shows several methods of using stones in drains : at A, clean round stones a are packed closely in half the depth of the trench, and covered by a turf clod b to prevent dirt washing down among them; at B, the round stones a rest on a triangle of 3 flat stones forming an open channel c; at C, the 2 flat stones a placed on edge are kept apart by a large rough stone b, and smaller stones c and a clod d complete the arrangement; at D, 2 flat stones a on edge support a third b lying flat, and this is overlaid by rough stones c and clod d; at E, the whole channel is formed of flat stones, 2 on edge and 2 flat, the earth coming immediately on the lid a.
All these are cheap, enduring, and effective plans, adapted to almost any country. The most perfect system is to lay earthenware drainpipes in the bottom of the trench, placing them end to end without joining thou, bo that the water may enter at the interstices.