Wells and Subterranean Water Supply.

Wells and Subterranean Water Supply.

(Continued from last week.)

Another point in connection with subterranean water deserves a word as we pass by. It is frequently asserted and maintained that subterranean water obtained from either open or driven wells in the immediate vicinity of rivers or streams is the natural and lateral infiltration from the latter, cither through its banks or bed. It seems to us that a moment’s reflection on the nature of things will challenge this theory, from the fact that is universally known that every stream is inclined to deposit more or less mud or silt in its bed and pass along in a practically impervious channel. Now, should there be any holes or springs in the bottom of the river or stream, would it be natural for the river waters to flow out) If this were the case would not our rivers be likely to lose in volume rathei than to gain as they proceeded on their course? And as our streams are almost invariably found in the lowest points of our valleys or water sheds, does it not follow that the waters from the surrounding territory, which is presumably higher, should be fed by the natural head which the elevation of the surrounding country would give, and being held down in many cases by an impervious soil preserve the pressure upward? This is the theory, but practice is better. For example, the author could name “a stream where this assertion was made, and to disprove it a well was dug along the shore of the river, in which the water on pumping maintained a level about four feet lower than the water level in the river following a suitable operation of the pumps.” When this was the case the earth over the whole water level on the river side was entirely dry, and extending it laterally until within less than two feet of the bank of the river caused no inflow of water from the bed of the river into the well, and this last few inches of soil proved itself to be dense and impervious to water, Such examinations have and often will prove that there is no connection between the gravel beds of a valley and the stream which drains it, but that the former is fed entirely from an independent underground source, many times flowing parallel to the river through the gravel and following in a general way the slope of the lund.

The author could name in his own experience several like cases, notably one at Watertown, Mass., where we put in a well approximating twenty feel from the river on a low bank, the surface of which was scarcely 18 inches above low water, and subject to overflow at all periods of flood. The mate~™Yterafew feet below the surface was large, coarse gravel, extending to the river bank, and apparently should have offered the freest of passages for the water from the river to the wells, the water level in which, when we were pumping, was from six to nine lect below the level of the river level. Vet, under analysis, these waters had little in common ; the temperature of the river water was in the vicinity of seventy degrees in midsummer and of the wells but a trifle over lifty. These wells were pumping from half to three-quarters of a million gallons per day. A bacteriological examination of the waters showed the river water to have 2,700 bacteria to the cubic centimeter, and the water from the wells but three. This should be pretty conclusive proof of non-connection or contamination. And it is a common occurrence with us to put down wells in the vicinity of ponds and streams and have a difference of fifteen to twenty degress in temperature in midsummer and midwinter which could not possibly be accounted for by the passage of the water did it come direct through so short a passage as that between the river or stream to the well or wells, for if a large quantity of water of higher or lower temperature passed through it would undoubtedly in a very short time reduce the earth by its modifying influence to an equal temperature, so that the two waters should be alike in this respect. And it should not be forgotten that this question of temperature of subterranean water is one not to be overlooked when considering it as a source of supply, for in summer it will nearly always be found vastly cooler than water fromasurface source, which is an important and desirable consideration iu the average community. And the author believes, taken as a whole, where subterranean supplies are possible, they are, as a rule, cheaper than the average supply of an equal quality and quantity of water taken from surface sources, for it is nearly always the case that a city or town of any importance will usually have to go some distance away for the purpose of obtaining a satisfactory and unpolluted source.

Now, having considered some of the advantages and made an appeal for subterranean water, it is well to add a few of the popular objections thereto, several of which in regard to permanence, quality, quantity, etc., have already been treated, but the chief of which in the eyes of the average community or individual is the objection that such waters are often hard. Considering this it is well to remember that it is difficult to obtain a water that is highly desirable for drinking purposes and at the same time equally desirable for manufacturing. When we look over the field, however, it seems to us that the health of the community deserves primary consideration. There are comparatively few lines of manufacturing save dyeing and a few chemical processes or work involving cooking or something in which the steam comes in contact with that which it would damage, where the trouble with the average hard water could not in most cases be practically connected, by the addition of a little kerosene oil, fed through a common sight feed luoricator. I’he writer is inclined to believe this a very desirable and almost costless boiler compound to cure either medium or fairly hard waters.

Now, while the writer may have appeared slightly enthusiastic on the subject of subterranean water, yet he is fully mindful of the many difficulties to be encountered in obtaining such supply. T he old and grossly erroneous idea that if one goes down deep enough in any given locality he is sure to get water should have been exploded long ago, but, alas, is not. If persons seeking supplies in the lower stratas where artesian wells have to be resorted to would consult geologists and obtain an accurate knowledge of what is likely to be encountered beneath the surface, they would sometimes save themselves a large expenditure, for an artesian well has its necessary requirements as well as the driven well or surface stream. There must be a roof and floor between which such waters must be confined if they are to be found in any quantity, though there is also usually existing chance of striking a fissure which may furnish one good well, though the likelihood of striking another is exceedingly remote; and the author could cite a case where a single artesian well gave as much as seven more, and a ten foot shaft sunk in the same locality for the purpose of increasing the yield, as there was only so much water there and one robbed the other. The same is practically true of wells in the upper strata. And the writer knows of few things, (except in obvious cases of the existence of a supply,) that requires more judgment and experience than the location of a large subterranean source of supply for a city or town, and many of the failures to obtain water are due to lack of knowledge, forethought, or experience. And many, again, to the lack of the application, the proper appliances or devices to fit the conditions. Practical well men and others are too prone to the practice of trying to make their favorite well point strainer, open well, or other appliance, do duty under all conditions, which is like trying to drive a square plug in a round hole and make a tight joint.

I he writer has been called to several places in the last two years, where a number of attempts by various people had been made to obtain a water supply and failed, and has located from one to five million gallons within a hundred feet of abandoned test wells which had been put down and the ground declared useless or impracticable for water supply. It is an apparent fact that in well work one has to deal with conditions as they are found and with materials as nature placed them. Consequently we have to make our methods subservient to this great mistress, and if we do not we are almost sure to fail. In locating the subterranean water supply,.great care should be taken to ascertain the available water shed with direction of its flow and the character of the material through which it passes and in which the plant must be located.

The writer is an ardent advocate of the driven or tubed welt, believing it in nearly all cases to be superior to an open well for the reason that in the first place an artificial head can be created by suctions in addition to any natural head due to the lowering of the water plane. As the open wall is merely a reservoir into which the water runs by natural gravitation, when the lever is lowered you have only gravitation to supply the deficiency and what you have taken away. The bottom of the open well or filter gallery is likely tosilt up and the flow to diminish from the fact that such wells can rarely be sunk to any great depth where much water exists in the first few feet, thus reaching only comparatively the top of the water bearing strata instead of penetrating it, which is the natural desideratum. And likewise being on the .wrong principle insomuch as they present their contact with the water strata on a plane and, on top when the rational method is vertical and by pertration.

Much could be said in reference to the location and fit condition for successful well plants, but so much depends upon surrounding circumstances that no given set of rules or suggestions could be made to satisfactorily cover the ground and be a reliable guide to one not well or thoroughly versed by experience in such matters.

There are many more points which the writer would like to cover on this interesting subject, but he feels that he has al ready taxed the patience of his listeners, and, as barely time remains for the mechanical details of putting this article on paper, he will close with a brief description of a plant recently designed by him and built by the Hydraulic Construction Company for the New Utrecht Water Supply Company, New Utrecht, Long Island.

The writer was called in a little over a year ago by the president of the above company, which was at the time suffering seriously on account of inadequate supply. Their then plant consisted of some eight open wells about six feet in diameter and approximating 35 feet in depth, constructed about 1886. These wells were of the ordinary type with a brick curb sunk to the depth above named and with a few large stones thrown in the bottom, but through which the finer sands had run and largely silted them up, reducing the yield so that under heavy draught the suction would be bad and the level lowered to the limit of the pumps. The president of the company was a great advocate of open wells and after our first interview employed a party to sink one of about 25 feet in diameter in the vicinity of the others. The contractor began the work, but after some weeks was compelled to abandon his attempt on account of the fineness of the material and water, which prevented him from carrying down his curb more than about 10 feet, as the sand ran in so that he could not make any practical progress. The result was, he gave up and we were again consulted. This time, mindful ol the president’s predilection in favor of open wells, we designed an atmospheric well to use in combination with his open wells which would not reduce the water level abnormally in the vicinity of the tube well plant, and, therefore, perhaps take the water away from and render his open wells useless. As they were in serious straits by this time for water, we were asked how long it would take us to put in wells to yield a million gallons, which we agreed to supply in ten days and actually finished in nine, increasing this amount up to nearly two million in sixteen days, which the author believes is about the quickest work for the quantity of water obtained on record. Having relieved their immediate necessities, we proceeded to put in the permanent plant of twenty 6-inch wells. These wells were designed after the general style of the annexed blue print. The wells proper were of 6-inch iron tubing, equipped with a special spiral copper non-corrosive strainer of 7 1-2 inches in diameter, as shown in the drawing, and designed by the writer. These strainers averaged aDout 6 feet long and were sunk to a depth of about 58 feet below the surface of the ground and presented a suction area about 50 times greater than a cross section of the 6-inch pipe. A flange was screwed on the upper end of the 6-inch pipe and on this was placed a chair with four frets on the bottom and with an aperture through it large enough to drop a 4-inch suction pipe inside, which pipe was sunk down to about the top of the strainer. This 4-inch receiving pipe had only a relative proportion of the area of the strainer of xoo to 1, and the result of such liberal proportion was almost beyond the writer s expectation. ‘This suction pipe was connected with a 6-inch well head and that by a ninety degree elbow to a 5inch cross section running at forty-five degrees’ angle to the main and connected thereto by a flanged Y, intersected by a gate valve, so that each well could be shut off without interfering with the operation of the plant. The suction main is 12 inches in diameter and the wells are located on a square 20×25. An expanded joint entered the receiver which had four 16-inch flanged openings, only two of which, however, were used and the others blanked. The receiver was a single casting, weighing some 6,000 pounds and being 5 1-2 feet in diameter and 7 1-2 feet high, covered with a manhole 18 inches in diameter, furnishing access for the removal of sand or for any other purpose. The joints and connections throughout the plant were flanged and bolted together with the intervention of rubber caskets. The wells were thoroughly pumped with a centrifugal pump for from two days to a week before being connected into the line, as the sand was quite fine and it took some time to get them clear. A 16-inch main approximating from 500 to 600 feet in length connects the receiver with the engine house, through which the water is pumped.

This is a very brief and inadequate description of a well plant which the writer believes is as successful and modern in proportio’n and design throughout as anything recently done. The results are equally gratifying, as every well on the plant will pump nearly 400 gallons of water, or approximately so, per minute, and the writer is advised, though he has not visited the plant for nearly a year, that it is giving perfect satisfaction. The pumping capacity of the works is approximately 4.000,000 gallons, consisting of two 2,000,000 Worthington pumps, one of which is a high duty ; and we are told that running days they run on about a 7-inch vacuum, and that the water is never lowered more than 23 inches, and that on the average consumption during the day it is only reduced 9 inches. And although the plant is operated under the Holly or direct system, during the night the water recovers, so that in the morning it is found to be only 4j£ inches below the normal. The water is of an exceptional character, being the most palatable, the author thinks, he has ever tasted, and so seems to be the general consensus of opinion in regard to its quality. The wells are located in an excavation some twenty feet deep, the material having been taken out some time ago and used for filling in and street purposes in Brooklyn. The writer can only approximate the yield of this plant, but is inclined to believe it would readily give six or eight million gallons, and that for low friction, high efficiency and quality of water it is worthy of notice. The quality of the water may be all the more surprising to some of our inland friends when it is remembered that this plant is located within a mile substantially of the ocean at Coney Island and within a quarter to a half a mile of an inlet or arm of Jamaica Bay.

The writer begs leave to offer his apologies for so incomplete and incoherent a paper, which has been dictated at a single sitting, without revision, for all of which please accept the apologies of an earnest brother member.

(To be continued)

Wells and Subterranean Water Supply.

Wells and Subterranean Water Supply.

The writer promised to prepare only a paper on the well plant recently constructed for the New Utrecht Water Supply Co., knowing the very limited time at his disposal, owing to a number of large plants on which final estimates and bids had to be prepared, and which allowed only some twenty-four hours for this purpose. Imagine his dismay when advised by a fellow member that his subject had been enlarged to the almost limitless one of “ Wells and Water Supply,” thanks to the zeal and enthusiasm of our ardent and beloved secretary.

That is a question which we all well know could be treated by volumes of interesting matter and deserves a more able and learned exponent than your humble servant.

The question, however, is of primary and most vital importance to all interested ir. water works in any department. The supply is, as a rule, a most difficult thing to get, and to maintain which we many times lay awake nights, and on the quality of which we are frequently damned and pilloried by the entire community, and without which it is hardly possible to imagine anything more us Bess than a water works.

The writer may as well at once declare that his hobby is subterranean water supply, and mounting the animal proceed to show a few of its paces.

There is little doubt but that the question of subterranean water supply is growing more and more prominent from day to day, and wells coming more and more into use, as our popula. tion increases and our streams and natural sources of supply become further encroached upon, and as a result polluted by human and animal and vegetable matters.

It is likewise true that our cities and towns are growing in size, and the number of important and suitable sources of supply within practical and financial reach of the average community are extremely limited, while many of the overground supplies now in use, if they have not already reached that point, are rapidly approaching a condition where they ought to be abandoned, or some rigorous steps should be taken to render them wholesome and fit for human consumption. l’rosperous towns, like little boys and their breeches, have a way of outgrowing their sources of supply. znd we believe that the average engineer, when called in in such case, is more or less prejudiced, and unless he has been brought in contact with a successful and satisfactory well plant or subterranean supply, is inclined to look far afield rather than immediately under his feet for a remedy or solution of his problem. It is but natural that the engineer, superintendent or manager of a water works should want to see his water and its sources to their very head waters. He naturally thinks that when he can see it, it must be there and can be depended upon, and consequently doubts the unseen and more or less doubtful possibilities of the subterranean supply, lie has heard of a failure here and there of a well plant, but let him remember that every day there are just as many failures or shortages occurring in old and assumedly long tried and thoroughly adequate surface sources, or by improper calculations or accident on new work, create little or no comment. Be it also remembered that while wells in their primitive form of open reservoirs dug in the ground are almost as old as the earth itself, any improvement on them, such as artesian wells, dates back but a few years, and the driven well is but little more than thirty of age. It is the latter well in its various forms which the writer is inclined to champion and to predict is to be the staff on which generations of our followers will lean.

ft is also worthy of note that the combination of such wells by ganging together and pumping simultaneously is younger yet, and I do not believe, while not guaranteeing myself as an accurate historian, that any plant of this kind dates back more than twenty years. As a consequence, it is but fair to presume it is yet in its infancy, and it is only fair also to make allowances for many mistakes and defective apparatus, location and details.

Now, before going far into the subject, the author is inclined to say a few words on the general question of subter. ranean water supply, correct a few prejudices, and place the advantages and disadvantages in fair contrast.

I .et us look at the question of subterranean water supply in a fair way. We kr.ow of no superintendent or city which is not proud to say and does not stick a plume in its hat overthe assertion, if such be the case, that their supply is pure spring woter. Now, let us ask you to pause a moment and consider what else is well or subterranean water save spring water in its best form? as you lap exactly the same source and your water goes through identically the same process of purification, and you are simply taking the water at a slightly more remote point or nearer its source than from the bubbling spring, which is merely the off-flow of an over saturated soil. Does it not stand to reason also that subterranean water must necessarily be of a very desirable character from a sanitary standpoint, for if, as we are advised by the advocates of filters, the worst specimen of water can be purified by passing it through a few feet, say 5 or 10 at most, of sand and gravel, why, therefore,is not water infinitely better filtered which passes through the earth which is nature’s God-given filter? And even let us say our well should be only 30 feet deep, w-e would have from three to five times the depth of filtering material overthe artificial filter; but, as isawell known fact,the amount of water which would fall on the area or territory actually occupied by a well plant would, as a rule, not furnish one per cent.of the quantity yielded,and it is but fair to presume that in a well plant yielding say a million gallons of water per day, to give a constant supply of such a quantity we must have a water shed or area approximating at least one square mile. This being the case, it is therefore seen that even should your water shed and source of supply be absolutely local in character you can approximate the average distance which the waterwould have to travel to reach a central point of delivery. From the standpoint of the sanitarium should not this be an excellent safeguard, when we are practically safe from the possibilitiy of an occurrence like that productive of the well known epidemic at Plymouth, Pa., where a mountain stream of presumably the purest and most desirable character was polluted by a small portion of typhoid poison in the form of human excrement getting into it, and the town almost decimated in population. What city with an open source of supply is free from the likelihood of such a calamity? While if we are taking water from a system of wells it would surely be most difficult for any of such poison to pass through even 50 feet of soil, presuming it were deposited in the immediate neighborhood of the well itself. Of course this does not argue, however, that certain wells have not been dug in improper places and poisoned by the infiltration of sewage; but in nearly all such cases the sewerage has existed in such large quantities and has been so well known and apparent that in the mind even of one not versed in such matters it was obviouusly unsafe to have ever sunk wells in such locality or permitted the encroachment of sewerage. There is also another unverified assertion,which is generously handed around, that the future or permanent yield of underground sources of water supply is a matter of great uncertainty. It would be but a matter of compilation to name almost numberless cities and towns in the United States and very large numbers in England, France, Germany, and throughout the continent, to disprove this assertion. It is true that expectations have in certain cases remained unfulfilled, but experience and pracice has shown the reason therefor; and an experienced specialist may in nearly all cases judge of the existing circumstance with reasonable certainty. To be candid, why should there be more uncertainty in underground water than in surface supply? It is an acknowledged fact among scientists and geologists that of the rainfall, as a rule,seldom more than one-third passes off by surface streams, and it is but reasonable to suppose that not more than another third is taken up by evaporation and vegetation. Thus, apparently, there is an off-flow by subterranean means equal to that which flows on the surface, and as these subterranean streams and sources are protected from the evaporative influence of the sun and wind why should they not be more permanent in their character than the underground stream? Again, let us look at it and ask this question, if it be true that water delights to seek the lowest available level, why is it not reasonable that the underground stream, parallel to the overground stream or in the vicinity thereof, should have a head and supply greater than that of the underground stream and be fed from a greater area? Again, in so much we know that all of our rivers, lakes and ponds are fed between seasons of rain by the gradual giving off of waters from the reservoirs of the earth by means of springs and other outpourings ; thus do not the vast resources of the earth as a water giver and reservoir tfecome all the more apparent ?