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^ arrangements for the reception of the lorry-borne water t be provided at forward-water points, where the tank lorries be quickly emptied into other improvised tanks whence they be drawn by the troops in their water carts. At J gal. per man 5 per horse per diem a division requires about 300 tons of water this means 150 to 300 lorries according to the state of the roads, lorry doing one trip per day. With pack animals, in countries e no roads are available, the same principles apply, only in ition to the contents of the receptacles carried for the troops, an iwance must be made for the carrying animals' own requirements. (d) During position warfare there are three areas to be con-
 * red forward, concentration, and back. The forward area, i.e.

tveen front line and the rear of the heavy artillery zone, will juire only drinking water for the fighting troops. This will be istributed (apart from any existing sources) usually from water -rts or lorries filling at " points " in rear. Tank trucks on light ilways and pipe lines to water points may possibly be used, but is is not so usual. While existing supplies should be utilized as ,uch as possible, it is obvious that the greatest precautions against intamination are imperative. Distribution by water carts (holding 8 gal.) and water lorries, i.e. ordinary motor lorries fitted with or more tanks, can be made where roads exist with sufficient rity against hostile fire. They convey water from the supplies in to storage tanks of temporary construction. These "spill tanks" the forward area should be small, numerous, and not too near "i other so as to distribute risk of damage by hostile action. Itered positions, convenient for the troops, should be selected for r location. In some soils (e.g. in chalk) it is possible to mine rground tanks holding large quantities, and to bring supplies of iter on light railway trucks. With heavy batteries in the vicinity light railways such tank trucks can be used to deliver water to lividual units. Storage for the daily supply must be arranged in ich cases. A piped supply to a forward area is hardly practicable tthin 5,000 yd. of the line, where shelling is active. Such a system quires much care in maintenance, will be subject to great risk of .mage and therefore to waste of water, hence it should not be adopt- without fnll consideration of other alternatives. If adopted the
 * eral plan should be very simple, with as few branches as possible

main lines. It is better to construct radiating lines from the ce rather than multiply branches. All pipes should be buried ith 3 ft. of cover ; although this involves their being out of sight, it is disadvantageous than the exposure to shrapnel and frost. Pro-
 * ed shelters for pipe repairs and maintenance parties, together
 * th supplies of tools and special fittings, must be arranged at inter-

along the lines. As frequent breaks may be expected, frequent ige points must be provided ; these will generally be a series of .1 tanks, say 400 gal. each, dug in and fed direct from the mains.
 * h points must be arranged to serve an area of the defence or made

the supply of dressing stations, etc. The ground must be well ined and all possible protection from shell fire must be given.
 * last stage of the travel of the water consumed by the troops in

front line must be by manual labour. Receptacles such as petrol i may be used, and when filled may be carried to forward dumps pack animals, tram lines, etc., so as to minimize hand carriage much as possible, but in the last resort men have to be carriers. .t the battle of Messines pipe lines were used to take water forward n catch pits on the Kemmel Hills, from sterilizing barges on the ', and from existing lakes, the quantity being 45,000 to 60,000 gal. [y. Arrangements were made to transport the water to the troops pack animals and carrying parties. During the attack, water
 * hed the troops within 20 to 40 minutes of the capture of ppsi-

s. This is one instance out of many which illustrate the applica- pf the principles above generally described. It is in the concentration area (the line of demarcation between this ad the forward area being taken as the rear of the heavy batteries) lat the main source of .supply and main arrangements for distribu- on to the forward area will be carried out. There will be in addition ctensive arrangements for troops in reserve, casualty clearing sta- ons, etc. Whether a comprehensive pipe system should be con-
 * ructed, whether there should be a number of pumping stations, or

nether there should be one or two main installations, are matters hich will have to be carefully considered in the light of local cir- amstances and available labour and plant. In any case a thorough ,'stem of control with personnel trained in manipulating the arious valves governing the branches, and a time-table giving quitable distribution, will have to be organized. The concentra- on area will be divided up into water areas with water "points" hence fighting units can draw their supplies by means of their water irts, but there will be casualty clearing stations requiring special ttention where water should be laid on to standpipes near kitchens, blution rooms, operating rooms, etc.

In the back areas the circumstances resemble those of a semi-

errnanent camp. The requirements will be for divisions in billets,

enforcement camps, schools of instruction, etc., and the arrange-

lents only differ from those in regular encampments in cases where

i villages, etc., it is found more convenient to have water cart

oints rather than piped supplies laid on to camping grounds.

(e) Before and after an attack the water supply arrangements

iclude the supply during concentration, and keeping up supply as

ie troops advance. In the former case the work is very much as

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already described for position warfare. Every endeavour must be made to develop resources rapidly and secretly on all parts where attack is contemplated, and the most thorough training must be given to the technical troops in the rapid extension of the water system. In Palestine prior to the great attack, material was brought during night to the farthest advanced positions, and concealed in orange groves, etc., while the personnel was drilled in rapid laying of pipes and erecting of pumping plant. The supply after the initial advance will depend on the nature of the country and the initial success, and the most complete and accurate intelligence of the water resources of the country is of paramount importance. While the construction of pipe lines in the rear of an advancing army may be of the utmost value in securing a position won (as at the Somme in 1916), it is hopeless with a rapid advance (as in Palestine in 1918), so that in this case either independent sources of supply must be relied on, or transport by lorry must take place, and this places a tremendous strain on the transport organization and is. therefore, not lightly to be considered. Where pipe lines are decided upon, it is well to take them in entirely fresh installations rather than attempt to extend existing systems.

(/) A few details may be added of various constructional matters common to all phases of operations.

" Filling points " are tank and standpipe installations where water carts, lorries, " dixies " and water bottles are filled. Preferably there should be separate standpipes and approaches for carts and for lorries, so that the one may not impede the other, but all the standpipes should be such as can be equally used by either. There should be provision off the main road for waiting vehicles (within call of the " point " police).

As there is a limit to the number of horses that should be watered at _ one point, it is best to establish numerous small "watering points," with 2OO-ft. run of troughs as a maximum, and to locate the positions of the stables accordingly. The troughs should be near a road, but not next a main road where strings of horses would impede traffic, and, above all, horses must not cross a road to reach the troughs. The approaches to the troughs and the standings must be well made, drained and fenced in ; otherwise the whole place becomes a morass. The frontage for each horse at the trough is about 2| feet. In an actual instance 6,000 cavalry horses per hour were watered at 500 ft. of trough, using both sides. This works out at 12 horses per ft. of double troughing, each horse being 5 minutes inside the enclosure. Probably the best figures for general use are 6 min- utes each horse and 2j ft. frontage. If watering is to be on both sides the trough should be at least 3 ft. wide. Canvas troughs (600 gallons) _ are 36 ft. long, and should be in strong framing.

Where, as is often the case in Oriental countries, water lies deep below the ground, necessitating the use of pumping machinery, the watering of large numbers of animals becomes exceedingly difficult. In the Palestine campaign the water distribution unit was I lift and force pump, with hose, and I 6oo-gallon trough, which unit with good management could water some 1 80 horses or 54 camels per hour. Only 18 camels can use a trough at the same time, and each relay takes 20 minutes to water. The requirements of a division are about 100,000 gallons a day, so each field company of Water Engineers carried 12 water units, or 36 per division. For the men's drinking water 10 large canvas tanks each holding about 1,500 gallons are needed. For storage, while at rest, large canvas bucksails, specially proofed and holding some 7,000 gallons, are useful, but it has been found better to construct tanks of masonry or planking and to reserve canvas tanks for mobile use. Copper vessels, holding 12 gallons, called fantassis, were used for camel transport.

Some notes may here be given about Oriental methods of raising water. The shadoof is a bucket hung by a rope to a horizontal swing- ing pole, slung from a vertical standard and weighted at the end furthest from the bucket. It can raise about 1,500 gallons an hour from a depth of 6 feet. The Persian wheel or sakkieli, a system of small jars working on an endless band round a vertical wheel above. a well, and actuated by oxen or camels turning a horizontal wheel, can raise 3,000 gallons an hour from 40 feet. The charsa, or skin bag, worked by a bullock hauling a rope attached to the bag over a pulley above the well, can raise 1,500 gallons from 40 feet.

IV. Distribution in Standing Camps and Cantonments. This is a comparatively easy problem. Certain quantities of supply will have to be assumed, in accordance with experience in similar cases, at various points, and then the sizes of the pipes can be calculated by ordinary hydraulic rules. But it is well to keep the sizes of the pipes fairly uniform, giving rather larger than the calculated diameters, both because the data on which the calculations are based are at best conjectural, and because it is well to avoid a multiplicity of different sizes. In designing the system it should be arranged that " dead ends " of pipes are avoided, i.e. that the possibility of water remaining stagnant in an isolated length of pipe should be reduced to a minimum. Supply will be from an existing town main, or from some independent source (well, river, etc.) whence the water is pumped to an overhead service reservoir that overlooks and can supply by gravitation the whole system.

V. Purification of Water. A safe water may be turbid in appear- ance and even disagreeable to taste and therefore repulsive; a dangerous water may be clear and palatable and therefore attractive. War experience has shown that few waters are so foul that they