Efforts at drainage, which is the greatest trouble during the winter months to troops occupying the line, must be as systematic and thorough as possible. Tinkering is of very little use and brings no results but causes a great and tiring expenditure of labor as far as the men are concerned, with no end of work in sight. When taking over a sector of line, the drainage system must be thoroughly studied and a line of campaign mapped out and strictly adhered to. Thorough work in the initial stages will save any amount of subsequent unnecessary fatigue and labor. The system to be applied depends entirely on local conditions, but full advantage must be taken of the assistance which nature affords. Water running down hill is a marvelous fact; nevertheless it is often overlooked. Field drains and natural streams anywhere near the trench must be kept clear of obstructions. These are usually attended to by the overworked farmers in peace times, but as they do not work near a trench system, it must be looked after by the army. Neglect of the natural watercourses has been the cause of much of the difficulty of draining the trenches themselves.

During the winter months a trench is never really drained. A mixture in the trenches which is neither water nor good, sticky mud, but a beautiful liquid combination of water and dirt, which is thick enough not to run, is formed. Sometimes it becomes sufficiently like water to be pushed or assisted to run down hill with scrapers, boards, and anything else that is handy. Sometimes it becomes sufficiently heavy enough to be shoveled over the parapet or put into sand bags. In either of these cases it is only overcome by persistent labor, but when the mud is in its true clayed self it is a waste of time and labor to attempt to move it, and the only way, without a large amount of cursing, is to sit tight and pray for the sun to dry it.

When a valley or dip is close to the side of a C.T. a few narrow gullies through the side, of about 18 inches in width, should be made so that liquid mud can be swept along the trench and on through the gulley to a natural fall. These little gullies or ditches should start at a place or places where there are dips in the level of the trench and must be dug straight through the side, as it then becomes easier to keep clear and gives no obstruction to the flow of mud; but if facing the enemy, it should not be in a straight line, as it then allows rifle fire into the trenches. If no other way is possible, then overhead traverse or other means of protection should be taken at that point. Sometimes, when it is not possible to complete these gullies, they should be dug out as far as circumstances will permit and a block of soil or very large sods be put at the junction of the gulley to the trench and the liquid mud dipped out of the trench and dumped into the gulley, where it will be prevented from running into the trench again by these collections of sods. This process is very slow, but conditions frequently make it the easiest and most convenient way of ridding the trenches of some of the mud. This work can be carried on by what is sometimes known as a “trench patrol” or maintenance squad, which is generally detailed from the company in the support line and which patrols the system of trenches held by their battalion during the day. The N.C.O. in charge generally reports serious collapses to his company officer, who in turn reports it to the engineers, who immediately take steps to have it repaired.

The width of drainage gullies should not be less than 18 inches, thus allowing easy use of brushes issued. With these brushes and adequate gullies, very long stretches of trench can be kept in excellent condition when the trench is wide enough to allow the drying effect of wind and sun to reach the bottom. The time spent in making these gullies is saved over and over again. If there be no natural valley or dip, a sump-pit is generally dug, the size depending on the energy of the troops digging it, but generally it is about 10 feet below the level of the trench it drains, and anything from 8 feet on in diameter. It is dug some fair distance from the trenches and in a position that will allow the maximum amount of gullies to be led to it from that particular section of the trench.

After having this system worked out, the next thing is to ascertain what parts of the rest of the trench system will not be affected by this drainage, and there to dig similar sump-pits just to the side of the trenches drained, small gullies leading to them. These need only be about 6 feet deep below the trench level and 4 feet in diameter. A short gulley, 12 to 15 inches wide and 2 feet long, should lead from the trench to the sump-pit, as shown in sketch of trench system.

Sometimes the sump-pit may be semi-circular and cut into the side of the trench, but in this case some barrier must be put across it to prevent men falling in while traveling at night. The former system is far more satisfactory, and especially so when the trench is hardly wide enough to allow the passing of traffic without touching the sides of the trench.

Entrances to these sump-pits must always be kept clear of all obstructions. Very often a ridge of mud from a man’s foot-mark is enough to put a sump-pit out of action. They should be continually emptied by pumping the contents over the parapet, or carrying in pails to the nearest gulley.

The side sump-pits must never be cut under the wall of a trench. On very short notice the roof will take the place of the excavated soil and there will be no sump-pit.

It is not always that pumps are available, and the few of those which are, are of no practical use for a length of time sufficient to be of any value; in fact, they hardly repay the fatigue entailed in getting them to the trenches. For ordinary trench drainage several small pumps are of far more use than one large one, as the range’s limited by the difficulties of removing it or by the length of pipe attached. These pumps, whether large or small, must be given a large and substantial platform, placed in some central position among a number of sump-pits. Each pump must have not only a discharge pipe, but a suction pipe, the latter being movable from one pit to another in the pump’s area without moving the pump. The placing of these pumps must be thorough and systematic, and those sump-pits not reached by pumps must be kept empty by means of pails.