Fig. 24.—Diagram of a spring.Fig. 24.—Diagram of a spring.
Fig. 25.—Water finding its way from a hillside.Fig. 25.—Water finding its way from a hillside.
Fig. 26.—The sinking of wells.Fig. 26.—The sinking of wells.
If the water is held in the ground as in the first case, it is possible to develop the spring artificially; that is, to drill through or bore through the overlying impervious strata so as to allow the escape of the water. When this happens, the water bursts forth exactly as in a natural spring except that under some conditions the pressure may be sufficient to force the water rising in a pipe instead of through the ground to flow above the surface of the ground as a fountain or jet, making what is known as an"artesian well." A true well, on the other hand, may be put down in the ground and through strata where springs could never develop; that is, where no pressure exists in such a way as to bring the water to the surface, as in Fig. 26. The well here is sunk until it reaches the water, and it is safe to say that one can always reach a layer of water in the ground by a well if the well is deep enough.
The flow of underground water is, however, always very uncertain and confusing, and even in localities where water would naturally be expected in quantity, as, for instance, in the bottom of a valley filled with glacial drift, much disappointment is often experienced because the expected water is not found. The city supply of Ithaca, New York, is a case in point. For six miles south of the lake there is a broad, almost level valley filled many hundred feet deep with glacial drift and presumably filled with water flowing at some unknown depth below the surface into the lake. When the city was recovering from the typhoid fever epidemic which, in 1903, committed such ravages, well water seemed to the panic-stricken citizens the only safe water. Geologists were called in, and they gravely asserted that the valley contained glacial drift to a great depth and that an ample supply of pure water could be counted on. It was known that water was met all through this valley at depths of from six to twelve feet and then that there would be found a layer of finely powdered silt to a depth of about one hundred feet, when another layer of water would be found, and that all the private wells reached this layer. When tested by the city, however, it was found that this water-bearing stratum wasof too fine material to yield its water freely, and the supply from the depth was altogether inadequate. In one section of the town large quantities of good water were found at a depth of about three hundred feet, and the city thought that other wells of the same depth should add to the quantity, but experiment showed that this three hundred-foot water was limited to one particular section, and after a considerable expenditure of money, an underground water-supply for the city was given up.
Ordinary dug well.
The ordinary well at a farmhouse is what is known as a shallow well or sometimes a "dug well," usually ten to twenty feet deep. This type does not usually pierce any impervious layer and thus reach a water-bearing stratum, otherwise inaccessible. The water is found almost at the surface, and the depth of the well is only that necessary to reach the first water layer. A very good example of this kind of well is to be found on the south shores of Long Island Sound, where a pipe can be driven into the sand at any point, and at a depth of a few feet an abundant and cheap supply of water may be secured. The amount of water that such a well can furnish depends upon the area from which the water comes and upon the size of the particles of sand or gravel through which the water has to percolate, it being evident that the finer the material, the more difficult for the water to penetrate.
The writer remembers superintending the digging of trenches in the streets of a city where the texture of the soil varied continually from clay to sand and even to gravel, all saturated with subsoil water into which wells could have been dug. It was very striking to see how thecoarseness of the material affected the quantity of water that had to be pumped from the trenches,—the finest sand requiring only one hand pump at a time, while the coarse gravel required either a dozen men or a steam pump to keep a short trench reasonably free from water. The same conditions exist when a well is in operation, modified by the fact that the coarse material yielding a larger supply will be most quickly exhausted unless the area drained is very large.
A shallow well is most uncertain as to its quantity and is likely to be of doubtful quality. There are, however, some examples of shallow well supplies which furnish large amounts of water; as, for instance, the one at Waltham, Massachusetts, or at Bath, New York,—the latter, a dug well some twenty feet in diameter and about twenty-eight feet deep, furnishing a constant supply of good water to a village of about 4000 people.
Construction of dug wells.
The construction of shallow wells requires little comment. Ordinarily, they are dug down to the water, or to such a depth below the level of the water as is convenient, by the use of an ordinary boat pump to keep down the water, and then are stoned up with a dry wall. Such a well for a single house requires an excavation of about eight feet diameter, with an inside dimension of about five feet.
Fig. 27.—Mode of sinking a well.Fig. 27.—Mode of sinking a well.
If the soil at the bottom of the well is sandy, it is possible to take a barrel or a large sewer pipe and sink it into the bottom of the well in the water by taking out material from the inside and loading the outside to keep it pressed down into the sand. This same plan may be used to sink the whole body of the well wall, first supporting the lower course of masonry on a curb, so called (see Fig. 27). This curb is usually made of several thicknesses of two-inch plank well nailed together, the plank breaking joints in the three or four layers used. It is a good plan to have this shoe or curb extend outwardly beyond the walls of the well so that some clearance may be had, otherwise the dirt may press against the walls so hard as to hold it up and prevent its sinking. While this arrangement may be put down in water, it requires some sort of bucket which will dig automatically under water and has not been therefore a customary methodexcept for large excavations where machinery can be installed. There is no reason, however, why the method might not be used for a single house.
Fig. 28.—A well that will catch surface waste.Fig. 28.—A well that will catch surface waste.
In whatever way the well is dug, one point in the construction that needs to be emphasized is that the wall should be well cemented together, beginning about six feet below the surface and reaching up to a point at least one foot above the surface. This is to prevent pollution from the surface gaining direct access to the well, and ifthis cementing is well done for the distance named, it is not likely that any surface pollution in the vicinity of the well could ever damage the water. Figure 28 shows the section of a well where no such precautions have been taken, and it is evident that not only surface wash, but subsurface pollution may readily contaminate the water. Figure 29 (after Imbeaux), on the other hand, shows a shallow well properly protected by a good wall and water-tight cover. Figure 30 shows a photograph also of this latter type of well. Even if a cesspool or privy is located dangerously near the well, in the second case the fact that the contaminating influence must pass downward through at least six feet of soil before it can enter the well is a guarantee that the danger is reduced to the smallest possible terms.
Fig. 29.—A well properly protected.Fig. 29.—A well properly protected.
Deep wells.
Deep wells are of the same general character as shallow wells. Usually, the ground on which the rainfalloccurs is more distant, so that the source of the water is often unknown, and usually, also, the stratum from which the water comes is overlaid by an impervious one.
Fig. 30.—A properly protected well.Fig. 30.—A properly protected well.
It often happens that there are several layers of water or of water-bearing strata alternating with more or less impervious strata, and that wells might be so dug as to take water from any one of them. Indeed, not infrequently in driving down a pipe to reach water, a fairly satisfactoryquantity is obtained at a certain level, and then, in order to increase the supply, the pipe is driven further, shutting off the first supply and reaching some other, less abundant.
Deep wells are reached usually by wrought-iron pipe driven into the ground. Sometimes this is done by taking a one-and-one-quarter inch pipe, with its lower end closed and pointed, and driving it with wooden mauls into the ground. When it has gone six or eight feet, it is pulled up, cleared from the earth, and replaced, to be driven six feet again.
Fig. 31.—Well-drilling apparatus.Fig. 31.—Well-drilling apparatus.
With ordinary soil, the pipe is easily withdrawn with a chain wrench, and two men will drive one hundred feet in a couple of days. When water is reached, a well point is put on through which water may percolate without carrying too much soil. This type of well is suitable for use in soft ground or sand, up to depths of about one hundred feet, and in places where the water is not abundant. It is most useful for testing the ground to see where water may be found and by pumping from such a well to see what quantity of water may be expected. This type is oftenused as a shallow well, and the author has seen such wells driven only a dozen feet. Such a well has no protection against pollution, and an ordinary dug well is better for shallow depths. A driven well always has a disadvantage also from the ever present danger that the iron pipe will rust through at the top of the ground water and so admit to the well the most polluted part of the drainage.
For larger supplies and for greater depths, a machine like a pile-driver has to be used for forcing down the pipe. This is not usually removed, but driven down as far as possible, and when the limit of the machine has been reached, a smaller size is slipped down inside the driven pipe, to be in turn driven to refusal. In rock, that is, if the well has to penetrate a layer of rock, a drill is used that will work inside of the pipe last driven, and by alternately lifting and dropping the drill, and at the same time twisting it back and forth, a hole through rock may be made many hundred feet below the surface of the ground. Figure 31 shows a cut of a common type of well-drilling machine.
In some soils, not rock, it is necessary to keep the drill going in order to churn up or soften the earth so that the pipe may be lowered. The churned-up soil is removed by a sand pump, which is a hollow tube with a flap valve at the lower end opening inwards and a hook on the upper end. By alternately drilling, pipe-driving, and pumping the wet material, length after length of pipe can be forced into the ground until water of a satisfactory quantity is reached. Very often a jet of water is used to wash out the dirt from the interior of the well instead of a sandpump. As shown by Fig. 32 water under pressure is forced down the small pipeAwhich runs to the bottom of the well. The large pipeBcan then, as the sand is loosened by the water, be driven down by the one thousand-pound hammerM. The water and sand together flow up in the space outside the small pipe and inside the large pipe, overflowing through the waste pipeW. This type of well has been very largely used throughout New York State; on Long Island, in connection with the Brooklyn Water-supply; along the Erie Canal, in connection with the Barge Canal Work, and in New York City, in connection with building foundations.
Fig. 32.—Sinking a well by means of a water-jet.Fig. 32.—Sinking a well by means of a water-jet.
Sometimes, when a shallow dug well does not furnish the required quantity of water, the amount of water can be increased by driving pipe wells down into water strata below the one from which the dug well takes its supply, so that water will rise to the strata penetrated by the dug well. This has been done to increase the public supplies at Addison and Homer in New York State. Unfortunately, much uncertainty exists inthe matter of the yield of driven wells, and an individual undertakes a deep well usually with great reluctance on account of the expense involved and the uncertainty of successful results. In level ground, conditions are not likely to vary in the same valley, so that if one well is proved successful, the probabilities are that wells in the vicinity will be equally so, and yet, at some places, the contrary has proved to be true.
One may estimate the cost of putting down four-inch driven wells as approximately one dollar per foot besides the cost of the pipe, which will be about fifty cents per foot. The cost of one-and-one-half-inch pipe would be considerably less than fifty cents, the cost of driving varying not so much with the size of the pipe as with the soil conditions. The writer recently paid ninety dollars for driving two one-and-one-half-inch wells to a depth of about one hundred feet, the above cost including that of the pipe; the soil conditions, however, were very favorable. In Ithaca the cost of driving one-and-one-quarter-inch pipe is fifteen cents per lineal foot up to about fifty feet deep with the cost of the pipe fifteen cents per foot additional. Below fifty feet deep the cost increases, since the labor and time required for pulling up the pipe is largely increased, and at the same time the rate at which the pipe will drive is notably diminished.
The question of pumping from wells will be considered in a later chapter, together with methods of construction and operation.
Springs.
Springs should be the most natural method of securing water-supply for a detached house, since no expense isinvolved except that of piping the water to the building. In Europe, spring water-supplies have been greatly developed in furnishing water for large cities. Vienna, for example, with its population of nearly two millions, obtains its water-supply from springs in the Alps mountains, and many smaller cities do likewise.
But in this country springs have been little used for water-supplies, partly because of the uncertain quantity furnished and partly because of difficulty in acquiring title to the water rights. If an individual, however, has on his farm, or within reach, a spring furnishing a continuous supply of water, it would seem quite absurd not to make use of such a Heaven-sent blessing. Care must be taken always that a spring is not contaminated by surface drainage, and for this reason, as with shallow wells, the wall surrounding the inclosed spring should be extended above the ground and made impervious to water for at least six feet below the surface. In some cases it may be wise to convert an open spring into an underground one, putting a roof over all and then covering with earth and sod. Figure 33 shows a type suggested by the French engineer, M. Imbeaux.
Fig. 33.—An inclosed spring.Fig. 33.—An inclosed spring.
Very often a larger supply from a spring may be obtained by collecting into one basin a number of separate and smaller springs. A swampy or boggy piece of ground is often the result of the existence of a number of springs, and if drains are laid to some convenient corner of the field, and a well dug there, into which the drains will discharge, not only will the swamp be drained, but an ample supply of water in this way be obtained. It would, of course, not be wise to have cows pasture in this part of the field, nor, even when the ground has been dried out, should this field be manured or cultivated. It should rather be fenced and left to grow up in underbrush, dedicated to the farm water-supply.
Extensions of springs.
Fig. 34.—A spring extension.Fig. 34.—A spring extension.
Again, if the water comes from a stratum W-W, as shown in Fig. 34, a large additional yield can be obtained by extending the spring from the point where it breaks out along the edge of the water-bearing stratum on each side. This extension or gathering conduit can be made by building rough stone walls on each side of the ditch, covering with flat stones so as to form a pervious channel to intercept the water and lead it to the chamber from which the supply pipe to the house leads out. The ground-water level will then be altered as shown by the broken line in the draining.
More simply it may be made by digging a trench along the hillside at the same level as the spring, or into the spring if necessary to find the water, and then laying draintile surrounded by coarse gravel or broken stone in the trench.
In the western part of the country much knowledge has been gained by investigating and experimenting on this kind of spring water development, only there the springs have been made artificially by digging down to meet the underground flow of water. For example, in the Arkansas River Valley, California, where it was suspected that water was flowing underground, a trench was dug transversely across the valley, and at a depth of six feet sufficient water was found to amount to 200,000 gallons per day for each one hundred feet of trench. On the South Platte River, near Denver, much the same thing has been done, and in a trench eighteen feet deep, water is collected at the rate of a million and a quarter gallons per day for each one hundred feet of trench. Other examples of the same sort might be given.
For a single house, the spring need usually only be extended by means of a short trench, and three-inch terra-cotta tile should be laid in the trench and surrounded by gravel and then covered over. The spring receiving water from these tiles should be inclosed, as will be described in a later chapter.
Supply from brooks.
Whenever a spring is not available and at the same time a supply of running water by gravity is determined on for a house, recourse is generally had to brooks which may find their way down the hillsides in the vicinity. In manyinstances the water in such brooks is practically spring water and is the overflow of actual springs. Where the brook is not subject to contamination between the spring and the point at which the supply is taken, the latter is as truly spring water as the former, and if a long length of pipe is saved, there can be no objection to the brook supply. On the other hand, it is suggestive, at least, of misrepresentation for a summer hotel or boarding house to advertise that their water-supply comes from springs when really it comes from an open brook miles away from the spring which may be indeed the origin of the brook, but with so many intervening opportunities for contamination that the pure original source is unrecognizable.
There are two obvious drawbacks to the use of brooks: (1) that the quality of the water is, in many cases, objectionable, and (2) that brooks are very apt to dry up in summer on account of their limited watersheds. The discussion on the first point will be postponed to a later chapter, and we have now to consider the question of quantity only.
The wisest plan before deciding on a brook supply is to measure the volume of water which flows in the brook at the time when it is lowest, probably about the middle of August. The actual volume of water needed for the household is not large, although its required rate of flow may be high and, as already pointed out, a stream which furnishes water at the rate of one quart in five minutes is sufficient for a family of three persons, a rate which is almost a drop-by-drop supply. Such a stream would require a reservoir somewhere in order to supply the faucets at the proper rate, and for a single family a small cistern oreven a barrel sunk in the ground would be sufficient for this purpose. An objection to the utilization of so small a flow in connection with the smaller storage is that the temperature of the water in summer is so raised that vegetation and animal growths take place easily and freely, so that the taste and smell of such water is most disagreeable. These consequences can be avoided even with the low flow by increasing the storage, since the larger quantity of water has been found to resist the bad effects of the low flow and high temperature. Figure 35 shows a small reservoir actually in use to supply water for a single house.
Fig. 35.—A reservoir for home use.Fig. 35.—A reservoir for home use.
Storage reservoirs.
But even if the stream actually dries up for two or three months, it is still possible to use it for water-supply, provided a suitable location for a dam and pond can be found where storage, as described in the preceding chapter, can be secured. For this reason as well as for the greater benefit to the quality of the water, brooks flowing through rough, wooded, and uninhabited country are to be preferred as a source of water-supply to brooks flowing through flat agricultural land, and in many cases, where their flow is largely due to springs, the brooks themselves may compare favorably with springs in quality.
Ponds or lakes.
Water may be properly taken from ponds or lakes whenever the danger from pollution is negligible. No better source of supply can be imagined than a pond in the midst of woods, far away from human habitation, presumably furnishing an unlimited supply of pure soft water. Sometimes water from such ponds contains large amounts of vegetable matter, the result of decomposition of swampy or peaty material, as, for instance, from the ponds in the Dismal Swamp of Virginia, so that the water has a yellow, coffee-colored appearance. The appearance of such water is suspicious, but it need not be feared unless something more pernicious than the coloring matter is present.
As the country becomes more settled, ponds are more and more likely to become contaminated and hence unfit for a water-supply, and this possibility must be taken into account in planning for a water-supply. It would be most shortsighted to carry a long line of pipe from a house to a pond several miles away, only to have the pond made unfitfor use within a few years by the growth of the community around the pond. The possibility of coöperation ought not to be overlooked, however. It is quite possible that half a dozen householders might be so located with respect to each other and to a pond that an arrangement could be made whereby the owner of a small pond would agree to fence it around and dedicate it to the purposes of a water-supply, doing this as his share. The others might then well afford to pipe the water to one house after another, including that of the owner of the pond.
Water from a pond or lake has one great advantage over water from a brook, namely, that contaminating substances in the pond settle out, so that pond water, especially if the pond is deep, is always of much better quality than running water. For this same reason, water taken from a reservoir on a stream is much better water than that in the stream above the reservoir indicates, and pollution is much less to be feared where the reservoir exists.
Pressure for water-supplies.
The value of a high pressure in the water-pipes of a house has been much overestimated. For a number of years the water-supply in the writer's residence came from a tank in the attic, the pressure in the bath-room being not more than ten feet, and while the water flowing through a three fourths inch pipe was noticeably slow, it was not so slow as to discredit the supply.
A height or head of twenty feet above the highest fixture in the house would be better and ought to be secured whenever possible. This head is obtained by having the source of supply higher than the highest fixture, not merely thetwenty feet mentioned, but also an additional height necessary to offset the frictional losses caused by the running water. The loss from this source in case of fire supply has already been referred to, but for purely domestic supplies the loss is appreciable. The maximum rate as already indicated is not more than 7000 gallons per day, whereas the fire rate both for single houses and for a small hamlet is about a million gallons a day. For the lower rate, as well as for rates one half and twice this rate, the friction loss in vertical feet per 100 feet run in small pipes is shown in the following table:—
Rate of Flow in Gallons Per Day1/2" Pipe5/8" Pipe3/4" Pipe1" Pipe1-1/4" Pipe350013.954.812.350.660.25700047.1717.307.452.040.7414000163.0957.825.006.642.41
The table shows how much additional elevation is needed over the 20 feet already referred to. For example, suppose it is decided that a rate of 1 quart in 10 seconds is to be maintained from three faucets or a rate of 7000 gallons per day. Suppose that a pond 4000 feet away is found to be 50 feet above the highest faucet in the house, and it is a question what size pipe ought to be used. By the table a 1-inch pipe loses 2.6 feet per 100 feet or 104 feet in the 4000 feet, an impossible amount when only50 feet are available, although the size would be entirely proper if the difference of level was 124 feet or anything greater. A 1-1/4-inch pipe, however, loses only 0.74 foot in 100 or 39 feet per mile, so that the 1-1/4-inch pipe would be necessary, although that size would answer even if the pond were a mile and a quarter away.
When water from a well is pumped to an elevated tank there is the same necessity of providing about 20 feet difference in level between the tank and the highest fixture, but the length of pipe involved being small, the friction losses are not great. It should be noted even here that too small a pipe may reduce the pressure, a 1/2-inch pipe causing a loss of 47 feet in a 100-foot pipe line. If a tower is built by the side of the house, the distance down to the ground, across to the house, and up to the second floor would hardly be less than 50 feet, and this is a loss of 23-1/2 feet, which means that the tank would have to be set higher in the air by this amount. With a 3/4-inch pipe, it should go 3.7 feet, and with a 1-inch pipe but a foot higher than the level necessary to make the water flow out of the faucet at the rate already specified.
A pure water-supply has always been regarded as desirable and its value can hardly be overrated, from the standpoint of health, happiness, or economy. From the earliest history, no crime has been so despicable as that of deliberately poisoning a well from which the public supply was obtained, and in the past no charge more quickly could stir the populace to riot. In Strassburg in 1348 two thousand Jews were burned for this crime charged against them; and as late as 1832 the Parisian mob, frantic on account of the many deaths, insisted that the water-carriers who distributed water from the Seine, shockingly polluted with sewage as it was, had poisoned the water, and many of the carriers were murdered on this charge.
Yet no water, as used for drinking purposes, is absolutely pure, according to the standards of chemistry. Distilled water is the nearest approach to pure water obtainable, and it is said by physicians that such water is not desirable as a habitual and constant beverage. The human body requires certain mineral salts particularly for the bones and muscles, and while these salts are provided in a large measure by food, a number are also furnishedby drinking water. On the other hand, a wonderful natural process is accomplished by distilled or approximately pure water in that the water tends to dissolve, to add to itself, and to carry away whatever excess of solids may exist in the body. For certain kidney diseases, for example, pure water is prescribed, not merely as a means of preventing further accretions, but for the purpose of dissolving and removing the undesirable accumulations already existing.
Practically, considerable latitude is possible in the matter of the purity of drinking water, and no particular harm is to be apprehended by the constant use of either a water containing as little as ten parts per million of total solids or of water containing as much as three hundred parts per million of total solids. The human body, in this as in so many other ways, is so constituted as to be able to adjust itself to varying conditions of food, and, until an excessive amount of ingredients are absorbed, no great harm is done. There are, however, certain definite substances—animal, vegetable, and mineral—which, when found in water, are decidedly objectionable, and it is not the amount of foreign matter in a water-supply, but its character, which is of importance in a water to be used for drinking.
Mineral matter in water.
The mineral matter is the least objectionable as it is also the most common, since all water is forced to partake, more or less, of the nature of the rocks and soil over which it passes. Good waters contain from twenty to one hundred grains per gallon of mineral salts; that is, of various chemical substances which are able to be dissolvedby water. If the amount is much in excess of one hundred parts, the water is noticeably "hard," and this may increase to a point where the water cannot be used. For example, the writer once superintended the locating and drilling of a well which passed through a bed of sodium sulphate or gypsum, just before reaching the water, so that as the latter rose in the well it dissolved and carried with itself a large amount of this salt, so much that the water was useless. Water containing more than one hundred grains per gallon of such salts as magnesium sulphate or sodium phosphate is a mineral water rather than a good drinking water, and while an occasional glass may do no harm or may even have desirable medicinal effects, such a water is not fit for constant drinking.
It is worth noting that many attempts have been made to show the relative effect of various hard waters on the health. A French commissioner reported that apparently people in hard-water districts had a better physique than in soft-water districts. A Vienna commissioner also reported in favor of a moderately hard water for the same reason. It is to-day believed by many that children ought to have lime in water; that is, ought to drink hard water to prevent or ward off "rickets" or softening of the bones. An English commissioner, on the other hand, has concluded that, other things being equal, the rate of mortality is practically uninfluenced by the softness or hardness of the water-supply. This same commissioner has also shown that in the British Isles the tallest and most stalwart men were found in Cumberland and in the Scotch Highlands, where the water used is almost invariably very soft (Thresh's "Water-supplies").
It has been asserted that certain diseases, not necessarily causing death, are caused by hard water, as calculus, cancer, goiter, and cretinism; but, as already pointed out in Chapter II, no satisfactory proof has ever been established. One must conclude that within reasonable limits there is little to choose between a hard and soft water for drinking purposes, although a change from a soft water to a hard, orvice versa, usually produces temporary derangements.
Loss of soap.
For washing purposes the value of a soft water is more marked. When a hard water is used, a certain amount of soap is required to neutralize the hardness before the soap is effective, and this takes place at the rate of about 2 ounces of soap to 100 gallons of water for each part of calcium carbonate per gallon, or about 3 ounces of soap to 10,000 gallons for each part per million increase in hardness.
The village of Canisteo, New York, has a hard spring water, the hardness being recorded by the State Department of Health as 162.8 parts calcium carbonate in a million parts of water. Clifton Springs water has a hardness of 208. Catskill, New York, which gets its water from a stream running down from the hillside, has a hardness of 22.1 or 140.7 parts less than Canisteo. Mr. G. C. Whipple says ("Value of Pure Water") he has found that 1 pound of soap is needed to soften 167 gallons of water when that water has a hardness of 20 parts per million, and that each additional part requires 200 pounds of soap to soften a million gallons. If Clifton Springs and Catskill should each use 100,000 gallons per day, theadditional cost of the hard water, at five cents a pound for soap, would be 20 × 140.7 × 0.05 = $140.70, provided all the village water were neutralized with soap. Probably not over one fiftieth part of the water is so neutralized, so that the added cost of soap is actually about $2.80 a day. Whipple expresses this cost asH/100 =D, where H is the hardness in parts per million andDis the cost in cents for every 1000 gallons used for all purposes. Thus Canisteo water costs 162.8/100 = 1.6 cents per 1000 gallons used, while Catskill costs only 22.1/100 or 0.2 cent on account of soap.
This discussion is intended to suggest a comparison between a well of hard water and a surface supply of soft water, when both are available. It should arouse an interest in securing a soft water as well as a clear water, and the advantages of the softer water, in so far as soap consumption alone is concerned, are seen to be not inconsiderable.
Vegetable pollution.
The vegetable and animal matter is organic in its origin and nature, and their effect on water may be taken up together.
Vegetable pollution is generally the result of decayed leaves, roots, bark, and such other vegetable tissue as would be likely to be found where the water-supply flows through a swamp or accumulates in hollows and depressions. This sort of water is likely to have a brownish or yellowish brown color, to have a slightly sweetish taste, and tobe soft, that is, free from mineral solids. Usually such water can be used for drinking purposes without serious consequences. Æsthetically, it is objectionable because of its color, and the city of Boston has expended many thousands dollars in building channels around swamps and in providing artificial outlets for swamps, so that the color of the water collected on the watershed shall not show the color induced thereby. Water from the Dismal Swamp of Virginia is so discolored as to look like coffee, and yet, in the vicinity, it is much prized for drinking, and formerly great pains were taken to fill casks with this water when in preparation for a long sea voyage.
Such matter always has a marked influence on a chemical analysis of the water, shows large amounts of nitrogenous matter, and apparently indicates a polluted supply; but, if the reason for this apparent pollution lies in the presence of a swamp, no danger to health therefrom is to be apprehended. Such water also is less subject to decay or putrefaction, and if a water-supply for a house is to be taken from a small pond, a gathering ground containing swamps is likely to furnish a more satisfactory water, color alone excepted, than one free from such swamps.
Pollution of water by animals.
Animal pollution usually comes from the presence on the watershed of domestic animals, that is, cows, sheep, and horses, or from manure spread on fields draining into the brook, or from barns or barnyards close by the water. It is the presence of this sort of pollution that furnishes the other kind of organic matter not to be distinguished by chemical analysis from the organic matter just referred to, but vastly more objectionable.
Drainage from houses and barns is responsible for the same kind of animal pollution, and while it is difficult to prove by statistics that such pollution is always dangerous to health, it is sufficiently repulsive from an æsthetic standpoint to be done away with whenever possible. Such pollution applies only to surface water, such as brooks or lakes, and the best method of detecting and evaluating this pollution is to make a careful inspection of the watershed.
If it is proposed to use the water from a certain stream for drinking purposes, the first step should be to examine carefully the area draining into the stream, to detect, if possible, all opportunities for animal wastes to find their way directly into the stream and to note whether fields sloping rapidly to the streams are manured; to see whether the stream flows through pasture land in which cows are kept, and especially to note whether houses with their accompanying outbuildings are near enough the brook so that water may at any time wash impurities down into the stream. Whenever a brook flows through woodland free from all animal pollution and not subject to pollution before entering the wood, the water is probably as pure as that in any spring or well.
On the contrary, when the water in a brook flows through a meadow used for pasture or through gullies, the sides of which are manured, or in the vicinity of houses and barns, the water is probably unfit for drinking purposes. This can be realized by standing at the edge of a barnyard and watching the rain falling first on the roof of the barn, then in larger quantities from the eaves on to the manure pile into the yard below, then accumulating inpools of reddish black concentrated liquid, until the volume is sufficient to form small rills which gradually assemble into a fair-sized stream. Similarly, the pig-pen drainage is washed out from under or even through the building, and, after combining with the barnyard drain, is carried into the stream near by. The very idea of drinking such filth is nauseating in the extreme. It is common for small slaughter-houses to be built on the side of a stream, so that the offal, carrion, and refuse of the place may be carried off without effort on the part of the owner, and there are a number of such places where brooks, used as places of deposit for slaughter-house refuse, discharge directly into the reservoirs of water works.
But this sort of animal refuse is not the most serious pollution. The leachings and washings from privies and cesspools, carrying, as they do, germs of contagious diseases, are most to be dreaded, and when a privy (with no vault underneath) is built on the side of a steep ravine and is so located that the natural drainage of the sidehill on which it is built cannot help but run around and through the building, then the pollution of the stream in the gulley is not only direct and inevitable, but of a deadly sort (see Fig. 36). Fortunately, the germs thus carried into the stream suffer the vicissitudes of all life exposed to the attacks of hostile forces.
At the time of freshets the streams carry mud in abundance, which mud is continually settling out of the water as opportunity offers, and with this settlement of mud there occurs also the settlement of the germs. Also the pathogenic or disease-producing germs are usually weaker and more susceptible than the putrefactive and otherorganisms which are found in the water in great abundance after any rain storm, and which tend to inhibit or destroy the pathogenic germs. But some will survive, and, with favoring conditions, may pass through the water-pipe to the house, causing sickness, if not death.
Fig. 36.—Stream draining a privy.Fig. 36.—Stream draining a privy.
Any inspection of the watershed, therefore, should look to the elimination of the dangers above described, and to the location of barns and barnyards, pig-pens and poultry yards, privies and cesspools, so that no direct drainage into the stream shall be possible.
It is out of the question for any surface water-supply to be pure, since the mere fact of the passage of water over the soil inevitably results in the collection of organic matter; and it is no exaggeration to say that the time will inevitably come in this country, as it has already in Germany, when no surface supply will be considered satisfactory unless the water is filtered. The only alternative is water gathered from areas that are owned by the individual and on which, therefore, all dwellings may be prohibited, all cultivated land avoided, and where the primeval forest may be restored, making the watershed equal to that from which forest streams emerge.
But usually, in the case of a single house, it will not be possible entirely to eliminate the dangers of surface pollution, although an inspection will show the dangers, and possibly some of them may be avoided. Certainly any direct drainage into the streams should be cut out, as well as the drainage from barnyards in the immediate vicinity of the point where the water is taken out. Just what percentage of pollution may be eliminated in this way it is impossible to determine, but it is not too much to say that no brook or pond should be used for a water-supply of a house unlessevery known pollutionof an organic nature has been removed. Under the most favorable circumstances there will be enough accidental contamination to make the water at times dangerous, and no added risks ought to be assumed.
In looking over a watershed the possibility of sewage entering the stream is, of all pollutions, the most to be avoided. To adequately investigate the quality of a stream, the inspector must satisfy himself as to the pointof discharge of the sewer of every house on the watershed, and this must be done personally, without apparently reflecting on the statements of the owner of the house. If any such points of discharge are found, the sewage should be either diverted into some other watershed, or spread out over the ground away from the stream, or purified by some artificial treatment before discharge, or else the creek water cannot be used.
The next point to be noted in the source of the water-supply is the presence and location of privies. These nuisances should be as far back from the banks of the streams as possible to eliminate all danger since the surface of the ground always slopes toward some stream, and pollution may be carried for considerable distances over or through the soil. Water-tight boxes can be provided so that no possible pollution of the surface-wash can occur, and if periodically the contents of these boxes be hauled away and buried, the privy loses its dangerous character. The city of Syracuse has installed on the watershed of Skaneateles Lake a most admirable system of collection of privy wastes, and the lake water is thoroughly protected, although there are several hundred privies on the watershed.
Cesspools, in general, are not dangerous if they are located fifty feet or more from the stream and if no overflow occurs.
Barnyards ought not to drain directly into streams, but when, as in so many cases, the stream flows through the barnyard, the only remedy is to move either the stream or the barnyard, and it is difficult to persuade even a well-disposed neighbor to do either. It is sometimespossible to appeal to his sense of right; but, too often, the neighbor feels that it is his land, his barn, his drain, even his brook, and he will do whatever he pleases with them, whether the water further down stream is to be used for drinking purposes or not. The question resolves itself into an inspection of the watershed and a determination of the existing conditions. If those are tolerable, the water may be used. If evident contamination is present, the water must usually be given up, and some other source of supply sought.
Well water.
The pollution of wells, if it exists at all, is usually very pronounced, and it is probably safe to say that, except where buildings, drains, or cesspools have been crowded too close to wells, or where some manifest and gross cause of pollution exists, a well water is safe to drink.
To protect properly a well from gross pollution, two precautions should be observed. The wall of the well should be built up in water-tight masonry, so that surface wash cannot enter the well except at a depth of at least six feet, and second, this water-tight masonry should be carried above the surface of the ground at least six inches and the well then covered with a water-tight floor so that no foreign matter can drop through the floor into the well or can be washed in by the waste water from the pump (see Figs. 28, 29, 30). If these precautions are taken, it is safe to say that nine tenths of the pollution occurring in isolated wells would be stopped.
Besides the above, a well may be polluted by a stream of underground water washing the contaminating matter through the soil. Experiments have been made to showthis very plainly. A large number of bacteria were placed six feet below the surface just in the top of the underground stream of water. Within a week they were found in considerable numbers in the water of the soil one hundred feet distant, but when the same number of bacteria were placed in the soil four feet below the surface above the level of the ground water, none of them found their way into the water of the soil. This experiment shows the folly of building a cesspool in the vicinity of a well when they both go down to the same water level, since the contents of the cesspool will be carried into the well if the underground stream flows in the proper direction. A shallow cesspool, however, would not be open to the same objection.
It is always difficult to detect the direction or flow of underground water, and various technical and delicate methods have been selected to make this determination. A very simple test, however, is to dig a hole at the point where pollution is suspected, carrying the hole down to where ground water is reached, and then to throw a gallon of kerosene oil into the hole, and if the ground-water flow is toward the well, the presence of kerosene in the well water will make the fact known. This would not, however, prove that the actual contamination would produce disease, since a liquid like kerosene can find its way through the pores of the soil to much greater distances than bacteria can be carried. But, to be on the safe side, water from such a well should not be used.
To make sure of the quality of the water proposed for a water-supply, it is wise to have such water examined by a chemist. The chemist will make certain determinationsof ammonia and other chemical combinations, and will report his findings with an interpretation or explanation of the result. What he finds is not the presence or absence of disease or disease germs, but substances that suggest or involve the presence of organic pollution. A test is made for the number of bacteria, and a well of spring water which contains more than about fifty in a cubic centimeter is a suspicious water. Surface water, on the other hand, may contain two or three hundred without being necessarily bad, the types of bacteria being harmless. Generally, a chemist will also determine the presence of the colon bacillus which is found in the intestinal tract of man or warm-blooded animals. Wherever this is found, in even such a small quantity as one cubic centimeter of water or less, there is strong presumption that the water has been polluted by human wastes and is therefore not fit to drink.
Dangers of polluted water.
Since no evidence of the danger of drinking polluted water can be so graphically expressed as by a direct reference to epidemics caused by the unwise use of such water, it will not be out of place to refer briefly to some of the instances in which a direct connection has been traced between a specific pollution of a certain water and disease or death resulting from it.
Although, as has already been explained, an infected water causes various kinds of intestinal disorders, particularly among children, the most characteristic evidence of pollution occurs when the noxious material comes directly from a typhoid fever patient, so that this same disease can be recognized as transmitted to another individualor family. This transmission of typhoid fever, while in some cases very plainly due to other agencies than water, as, for example, milk, oysters, and flies, yet, by far the largest proportion of the transmitted cases comes through the agency of polluted drinking water, and there are many examples both of contaminated wells and streams which emphasize this possibility beyond all question.
Two historic investigations of epidemics which have thoroughly convinced sanitarians that typhoid fever is a communicable disease and that water is the vehicle for its transmission may be briefly cited.
In 1879 Dr. Thorne reported an epidemic in the town of Caterham, England, which he had investigated, and disclosed the following facts: The population of the village was 5800. The first case of fever appeared on January 19. Others followed in rapid succession, until the number reached 352, of whom in due time 21 died.
The possibility of infection was carefully looked into. The influence of sewer air was ruled out because there were no sewers. The milk supply was proved unobjectionable. No theory of personal or secondary infection could account for the widespread prevalence, particularly as only one isolated case had occurred during the preceding year, and this had been imported.
Of the first 47 persons attacked, 45 lived in houses supplied with the public water-supply, and the other two were during the day in houses supplied with public water. Further, in the Caterham Asylum, with nearly 2000 patients, not a single case appeared, their water coming from driven wells. Investigation of the water-supplyshowed the undoubted cause of the epidemic. The public water-supply was derived from three deep wells, connected by tunnels in the chalk. In one of these tunnels, from January 5 to the end of the month, a laborer worked, who, though unattended by a physician, was evidently suffering from mild typhoid fever, the symptoms of the disease being carefully detailed by Dr. Thorne. The laborer at the time of his going to work had a severe diarrhœa, and while in the tunnel was obliged to make use of the bucket, in which the excavated chalk was hauled to the top. He admitted that at times the bucket, in being hauled up, would oscillate in such a way as to spill part of its contents and thereby pollute the water of the well below. Two weeks from this accidental pollution the epidemic began, and there can be little doubt of the relation of this mild case of typhoid to the epidemic which followed.
A second illustration may be cited at Butler, Pennsylvania, which occurred in 1903. The water-supply of Butler, a borough of 16,000 people, comes from a reservoir on the creek which flows through the phase. On account of the gross pollution of the water at the pumping-station, a long supply pipe has been laid from the reservoir directly to the pumps. The water also was filtered through a filter of the mechanical type. Through some accident the filter was thrown out of service for eleven days, between October 20 and 31, 1903, and unfortunately, on account of the failure of the reservoir dam, the water was at that time being taken directly from the creek at the pump well, and had been since August 27. Only ten days after the filter was shut down, the epidemic broke out in all parts of thetown. Between November 10 and December 19 there were 1270 cases and 56 deaths. In the subsequent investigation it developed that not only was the stream generally polluted by the sewage at various points above the intake, but that there had been several cases of typhoid fever on the watershed, some on a brook that enters the creek within one hundred feet of the filter plant. As at Caterham, the inference is patent that the introduction of some specific infection into the drinking water was the direct cause of the general epidemic.
The occasional outbreaks of typhoid fever which occur in single families are not so easy to explain, particularly since the small number of persons affected does not usually call for a widespread interest on the part of those experienced in such epidemics. In the Twenty-seventh Annual Report of the New York State Department of Health, the following description of an outbreak in a small hamlet, where the cause seems to have been the use of a pond for a wash tub by some Italian laborers, thereby transmitting the disease germs from their clothes to the water afterwards used in a creamery, is given. The diagram, Fig. 37, shows that the creamery secured its water for the purpose of washing cans from a small pond by means of a gravity pipe line. The foreman of the creamery, who boarded at the residence markedA, first contracted typhoid fever. A week later an employee at the creamery also contracted the fever, the residence of the latter being markedBon the diagram. About six weeks later the railroad station agent, living at the point markedC, contracted the fever, and two weeks later his wife was attacked with the same disease. The residences atBandCare only about three hundred feet apart, both families taking their water-supplies from a spring between the two, but nearerB. During the summer previous to this outbreak a gang of Italian laborers, engaged in double-tracking the Central New England Railroad, were housed in box cars standing on one track of the railroad. One of the members of the gang was reported to have been taken ill with a fever and was at once removed, it was supposed, to a hospital in New York. It was the practice of the Italian laborers to bathe and wash their clothes in the upper of the two ponds from which water is supplied to the creamery by the pipe line. All the persons who contracted the fever were supplied with milk from the creamery. The foreman, who was the first to contract the fever, used water from the creamery and from the well at the house where he boarded. The other families, as already mentioned, used water from the spring. The conclusions, therefore, are that the creamery in some way became infected with typhoid fever, probably through the water-supply from the pond, and that the first two cases were due directly to this cause; that the station agent and his wife contracted the fever because of the infection of the spring, either from some small stream which is the outlet of the ponds or from some infection due to the illness of the owner of the houseBnear by. The report concludes as follows: "The use of water for creamery purposes from a pond exposed to such unwarranted and unchecked pollution as is shown here, or the permitted abuse of a water-supply for a creamery, appears little less than criminal negligence on the part of those responsible for the management of the creamery."