IN compliance with the request, contained in your letter of the 18th of December last, I have taken the earliest opportunity, which my engagements and the state of the weather would permit, to ascertain the practicability of introducing the water of the Bronx into the City of New-York. The result of which investigation, I have now the honour of transmitting to you, requesting that you will lay the same before the Common Council, who, as the immediate guardians of the city, must feel peculiarly anxious to possess such information on the subject, as may enable them to determine upon the propriety of the measures, necessary to be taken to accomplish that important object.

I AM sensible that Estimates of the expence at­tendant on the execution, would have been a desira­ble piece of information; but a wish to render them as accurate as the uncertainty of the business will admit, induces me to request a further indulgence of time, to procure information on several material points, essential to be known, previous to the com­pletion of the necessary calculations, but with which I am at present unacquainted·

[Page 4]THOUGH the amount of the expence, ought, and doubtless will, have a proper degree of influence on the final decision; yet perhaps it is not a disadvan­tage in the first instance, that the question should be determined on its abstract merits alone.

IN an object of this nature, the first point to be fixed, is the Quantity of water, necessary to be de­livered in a given time: was nothing more required than a sufficiency for culinary and other domestic uses, the matter might be easily ascertained. But as the principal object of this undertaking, is the in­troduction of a copious and constant supply, for cleansing and cooling the streets, it becomes a ques­tion of importance to determine, as near as may be, the annual amount of the required demand. Seve­ral specific quantities have been mentioned; but in my opinion, they are all inadequate to the contem­plated purpose. In this, as in all other undertakings, I conceive it to be an object of the first consequence, to have the effect dependent on the will, and where, from the nature of the thing, no certain conclusions can be obtained, it is wisest to err on the safe side.

WHATEVER doubts may be entertained of this deduction as a general principle, I believe there can be none respecting the propriety of it in the present instance; for, however great the amount of the sur­plus water may be, there are a variety of useful, and productive purposes, to which it may be advan­tageously applied. Proceeding on this ground, I have endeavoured to calculate as near as the want of sufficient data would enable me, the Minimum quan­tity necessary to be introduced in 24 hours. Tho' conclusions deduced from Hydraulic principles of the expence of water issuing from pipes of given dia­meters placed on the summits of the several streets, would have been much preferable to vague guesses; yet the infinite variety of cases, arising from different [Page 5] degress of depression below, and distance from the principal Reservoir, would have rendered the opera­tion a very laborious one, and from a variety of causes, the result very uncertain. Indeed, every mode, with which I am acquainted, may be objected to, on the latter principle, but though it is perhaps impossible to ascertain the exact truth, we must en­deavor to approximate as near thereto as possible.— Conceiving it to be the intentions of the gentlemen, who have recommended the measure of washing the streets, as essential to the health of the citizens, to have a regular and plentiful current of water run­ning at least twelve hours every day, through all the streets, by means of pipes placed at the respective summits, producing an effect, similar to what we may observe to be done, by a moderate shower of rain of the same duration. Calculating therefore, the area of the city; the quantity of water usually descending in the time above mentioned, and making due allowance for such parts of the general surface, as are pervious to water, we shall obtain a result, that perhaps on the whole, will be as near the truth as can be done by any other mode, and sufficient to answer every purpose required. I find that the area of the city, bounded by the East and North rivers, and the intersection of them by Grand-street, is up­wards of 750 acres, and making an allowance of 350 for public squares, gardens, and other unpaved surfaces, we have a remainder of 400 acres; which being unpenetrable to the rain, all that falls on that surface, must be discharged by means of the Channels of the different streets, into the adjacent rivers. I have made various enquiries, but have not as yet re­ceived any correct information of the quantity of water produced by a moderate shower, of 12 hours continuance. I am, therefore, under the necessity of assuming as a fact, what may hereafter be proved to be erroneous, though I have reason to believe, that my calculations will not be found to be over-rated. [Page 6] Fixing, therefore, the depth, as shown by the rain­gage, at one fourth of an inch, we shall find the total amount to be 363,000 cubic feet, or 2,221,560 ale gallons, and adding to this 778,440 gallons, as an adequate supply for domestic consumption, we shall have Three Millions of gallons to be introduced into the reservoir every twenty-four hours.

I BEG leave to observe, that an encrease or dimi­nution of the above quantity may be effected by one of the plans, submitted to your consideration, without materially altering the design or enhancing the estimates, while by the other, the expence will be nearly proportioned to the quantity required. I offer the preceding calculation, merely as an essay to de­termine a point, which as yet has remained undis­cussed, though of such importance, that I deem it the basis of the whole work. I shall readily yield to any valid reasons, that may be produced in support of variations from the above conclusions.

THE quantity requisite being determined, the next point to be ascertained, is from what sources it can be most conveniently derived. I am acquainted with but two modes, that deserve any consideration. The first is the introduction of a part, or the whole of the waters of the Bronx—The second is a supply obtained from the springs of the Collect. As this question has much agitated the public mind, and each plan in its turn been extolled or decried by their respective advocates and opponents, it has produced, (what is frequently the effect of a collision of senti­ments) a more obstinate attachment to pre-conceived opinions. I do not, therefore, expect that any argu­ments which I shall produce, will reconcile the jar­ring interests. Yet I trust that the statement I shall offer, (and it is the result of some experience and reflection), will enable those whose province it is to judge of the merits and disadvantages of the different [Page 7] plans, to select that, which on the whole shall be most conducive to the public welfare.

IN order to form a correct opinion on the subject, it is necessary to take into consideration, the efficiency of supply; the quality of water, as it respects the different uses to which it is to be applied; and the expence of execution.

ON the first of these heads, I am aware that it has generally been believed, and pretty confidently maintained, that at those seasons, when the demand will be greatest, and most essential, that the wa­ters of the Bronx are wholly inadequate. These assertions have been made with a degree of positive­ness, that would induce one to believe, they were founded on the most careful and accurate expe­riments, which I have every reason to imagine, have as yet never been made; instead of which, I have no doubt they are the random guesses of superficial ob­servation. The question is of such importance, that we ought to be very careful, that we proceed upon the most certain grounds. In a matter of this con­sequence, I may be allowed to be a little diffuse.

IT is evident that at the period, when the greatest supply of water is wanted, there will, from natural causes, be the least quantity furnished. This is a common principle, applicable to all rivers, and springs; the very few examples to the contrary, are mere exceptions to the general rule. This circum­stance, has created doubts in the minds of many persons of the efficiency of the Bronx. Previous to my examination of that stream, I had regretted that proper experiments had not been made, at the season above alluded to, as then the fact would have been ascertained beyond all dispute. It is uni­versally allowed, that for the greatest part of the year, there is a super-abundant quantity; what the [Page 8] diminution may be, is not easily ascertained; we must rely altogether upon the information of those persons, whom a long residence has afforded the best opportunities of judging of its usual decrease; but as not materially interested on the subject, we cannot expect any considerable degree of accuracy in their observations—Allowing for this circumstance, I have been careful to take the lowest average of the re­sults of three distinct cases, founded on the best data I could procure, and applying to them well known Hydraulic laws, I am persuaded that the natural stream of the Bronx alone, if conveyed with­out waste, would be fully adequate to the supply before mentioned; but fortunately a minute accuracy is not required, as will appear by the following ac­count of the River Bronx,

WHOSE principal source is from a Lake, about 4 miles to the Northward of the White Plains, known by the name of Rye Pond. This is a beautiful sheet of water, upwards of a mile in length, containing, as appears from an old survey, upwards of 500 acres of water; which flowing from the outlet, is receiv­ed into another pond, a short distance below; whose area exceeds 50 acres. From this pond it descends with a rapid current upwards of a mile, to Mr. Ro­bens's Mill; a few rods below which, it unites with the other branch of the Bronx. This last, which has its origin in a swamp a few miles to the North­ward, retains the name of the Bronx, to its source; yet it is the least considerable stream, particularly in the Summer, when it is reduced to a small current; while the other branch is sufficiently large, to turn an overshot wheel, twelve hours out of twenty-four, in the driest times. Rye Pond is bounded by high and bold shores, which tending towards each other at the outlet, are admirably calculated for the form­ation [Page 9] of an immense Reservoir. This being filled during the winter and spring, may be retained until the month of July, when the natural supplies begin to diminish, it may then be discharged periodically, so as to afford any given quantity of water, that may be requisite for the use of the city.

THIS Lake is supplied wholly by springs, many of which are internal, and few of the others originate more than a mile from the head; these are so con­stant and copious, that no doubt can arise of their capacity to fill the Reservoir to the contemplated height of six feet, which may easily be effected by throwing a dam across the outlet of the lower pond; this would form a sheet of water of more than 600 acres in extent, containing 959,713,920 gallons of water; affording (independent of the natural stream of the Bronx) a diurnal supply of nearly Eight Millions of gallons, for 120 days; three eighths of which quantity is sufficient for our purpose; the sur­plus, Five Millions may be given to the Mills below the point of partition; so that instead of injuring (and consequently recompencing them for the dam­age,) the Mills on the Bronx as has been generally apprehended, they will derive essential benefits from the measure. Having, I flatter myself, removed the doubts of the most incredulous, respecting the effici­ency of the supply to be derived from the Bronx, it remains to examine the competency of the waters of the Collect. The general bias of opinion seems to lean in favour of this scheme; and if it can be made satisfactorily to appear, that the required supply can be obtained from this source, I am ready to al­low that it is a work, that would be soonest accom­plished, and attended with the least expence. But we ought to be extremely cautious in hazarding an experiment, where the cost would be so great, and the event so doubtful. The question is of infinite importance, and unfortunately, one that cannot be [Page 10] determined by abstract reasoning. The capacity of the Collect, has been attempted to be proved, by its present extent, but that in my mind is a most falla­cious mode of reasoning; for however great that may be, a powerful Steam Engine would soon ex­haust it, unless replenished with numerous and copious Springs; on these alone, therefore, it is evident we must depend; and I know of no other mode of es­timating their combined effect, than by calculating the quantity of water issuing from the outlet of the Collect; which even at this time is so inconsiderable as scarce to deserve attention, and if my information is correct, it ceases to flow altogether in the summer. I am sensible that we should not too hastily conclude, that the above is the total amount of the supply that may be derived from this source; I think it very probable, that from the nature of the surrounding ground, (which is a coarse and porous gravel) a con­siderable portion thereof, may percolate through, into the adjacent rivers. Much, and perhaps the greatest quantity, is also daily drawn off by the Tea-Water Pump; which from its vicinity, I have no doubt is supplied from the same source.

IT is true that by sinking deeper into the earth, an augmentation of quantity would be procured, yet if we went lower than the surface of the Tide Water, I apprehend that the quality would be materially in­jured. Leaving the question, as I fear it will remain, undetermined, we next proceed to examine the quality of the respective waters. To appreciate their merits fairly, we should judge of their utility, by the extent of their application: Proceeding on this ground, I believe it may be safely affirmed that the water of the Bronx, is at least equal to that of the Collect, though this is contrary to the general opini­on. The only reason that I can perceive for the pre­ference usually given to the last mentioned, arises solely from its superior coolness. However grateful [Page 11] this may be to our feelings, it does not follow that it is equally conducive to our health; for whatever degree of purity it may now possess, the period is not very remote, when from the natural encrease of the city, these springs must be subject to those con­taminations, which have already rendered so many wells unfit for use; an evil that is daily encreasing, and to which no effectual remedy can be applied.— This to me has ever appeared an unsurmountable objection. The idea of supplying a large city with Pure Water, from a Reservoir in its center, has al­ways been a very strange one to me. From the re­presentations made respecting the water of the Bronx, I believe many persons have hastily concluded that it was unfit for use. When it is considered that the principal cities in Europe, are necessarily supplied from Rivers, and with water, generally taken from those parts, which from a variety of causes, are most impure, and yet that the experience of ages has not evinced any known ill effects, arising from the prac­tice, I conceive that little fears will be entertained of the salubrity of the water of the Bronx—which is a collection of innumerable Springs, issuing from a rocky and gravelly country, and running with a rapid current, over a bed of the same materials. It will be conveyed into the city without any additional impurity, and e're it is distributed from the Reser­voir, will by a mode of purification hereafter de­scribed, be rendered as clear as Spring Water.

THE next object to be ascertained, is the practica­bility and probable expence of accomplishing the re­spective plans: And here it may not be amiss to ob­serve, that in a matter of such immense consequence to the present and future convenience and welfare of the city, every local view, every subordinate conside­ration, should yield to the general good; that a re­gard to the primary object alone, should decide the question, regardless of a paltry difference of expence, [Page 12] or the immediate emolument to be derived from the undertaking. On the first of the above mentioned heads, there have been a diversity of opinions, which, previous to an actual survey, was not to be wondered at. These doubts must now be removed, as it ap­pears from the examination that has been recently made, that the Bronx is sufficiently elevated above the highest parts of the city, to introduce its waters therein, without the aid of machinery; and the in­termediate ground, though very irregular, presents no obstacles which art and industry may not sur­mount. A general view of the subject, is all that I am able now to present; and all that is necessary to be known, in this stage of the business. An outline of the plan, I would recommend for adoption, as best adapted to the varying face of the country, will be sufficient to enable you to form a tolerable correct idea of the eligibility of the measure.

THE best situation I have yet seen to draw the wa­ter from the Bronx, is a short distance above Mr. Lorillard's Snuff Mill; a break in the western bank, enables us to divert the stream (by means of a dam thrown across it) without any difficulty. The water being raised six feet above its natural level, will flow over a small swamp, from which originates the little rivulet called Mill Brook; following the direction of this stream, a canal may be drawn along its northern bank at a small expence, for the distance of three miles; when the ground falling off rapidly, renders it necessary to cross the valey in which Mill Brook runs, by means of an aquaduct, to the opposite rising ground; along which the level may be preserved, to the heights above Haerlem river. An open walled canal, will be the cheapest mode of conveying the water so far; a little loss is not material, as a small increase in the section, will remedy such waste.

[Page 13]A DECLIVITY of 6 inches in a mile, with a section of 1,152 and linear border of 89 6-10 inches, will oc­casion a velocity in the current sufficient to introduce into the small reservoir at the extremity of the canal, 6 cubic feet of water per second; which is more than the quantity required, supposing the daily supply to be three millions of gallons. The most difficult and expensive part of the route, will be the conveyance of the water across Haerlem river, the most eligi­ble mode of effecting this, appears to me, to be by means of cast iron cylinders, of two feet diameter, with a difference of 8 feet between the extremities. This descent will produce a velocity of 22 3-4 inches per second, yielding in that time 5 95-100 cubic feet, while the required quantity is only 5 65-100. From the Cylinder to the Reservoir, it is a matter of con­sequence to preserve as much of the water as possible: to effect this object, the bottom and sides should be rendered impervious to that element. An absolute necessity to preserve a regular and uniform descent, leaves us little room, in the choice of our route: which will be chiefly along the shore of the North river. The quality and make of the ground, vary much: the greatest impediments are occasioned by the numerous ravines, which intersect the line of the Canal—over all these, aquaducts must be constructed. The level may thus be preserved upwards of 6 miles, or within 2 miles of the city; there it descends so much, that unless higher ground can be found, it will again be necessary to have recourse to iron Cy­linders, to convey the water into the Grand Reser­voir, which may either be placed in the Park, or a vacant piece of ground to the Northward of the Hospital, either of which are sufficiently elevated to distribute the water through all parts of the city.— The total distance from the Bronx to the Park, is 14 miles 7 furlongs, and the descent twenty three feet. It is to be observed that the principal object of this survey, being to ascertain the practicability of the [Page 14] plan, and neither my time or the season, permitting that minute investigation, which is necessary to be made, previous to the commencement of any ope­rations, there is a probability that advantageous de­viations may be made from the route pursued.

ALTHOUGH the form and dimensions of the reser­voir, are objects of importance, it is now prema­ture to point out the particular mode of construction I would recommend to be adopted; yet it may not be improper to give a general outline thereof, as perhaps it may tend to remove many of the preju­dices which have been entertained against the sup­posed impurity of the waters of the Bronx. It is proposed to divide the Reservoir into three parts, two of which will again be subdivided; each of these minor divisions capable of containing a daily supply of water. The first division, or reservoir of Reception, will contain the water as immediately delivered by the Cylinder of discharge; while one of its subdivisions is filling, the other in a quiescent state, will be depositing the adventitious matter, with which the water may be intermixed. After so re­maining 24 hours, it will be drawn off by an aperture near the bottom (so as to prevent any buoyant par­ticles from entering) into the Reservoir of Filtration, where it will still further purify itself, by gradually depositing the remaining sediment, until it is finally received into the Reservoir of Distribution, after percolating through a bank of washed sand and gra­vel, (in imitation of that natural process to which all water owes its purification)—This last Reservoir it is proposed to Arch over, so as to preserve the water pure and cool; from hence it will be distribut­ed in separate and distinct pipes, through every part of the city.

THE water destined to cleanse and cool the streets may be taken immediately from the Reservoir of re­ception, [Page 15] as I conceive it is not necessary, that it should be very pure.

THE surplus water, which for a considerable part of the year, will not be wanted for washing the streets, may be applied to a variety of purposes, but perhaps to none more useful or advantageous, than the supplying of Dry Docks, which may be construct­ed to receive the largest ships.

IF the water in the Collect is deemed adequate to all the purposes of domestic consumption, it must be raised by means of a Steam Engine, into a Reservoir; the situation before mentioned, will in this case be very convenient—Although one Engine might be constructed, so as to raise, both the water for wash­ing the city, and for family use; yet as from the quantity necessary to be raised, it would be unwield­dy in its parts, and more liable to accident, and also as two thirds of its powers would be useless the great­est part of the year, I believe it will be most advisea­ble to erect two—the first destined to raise the water for cleansing the streets, placed at the foot of the hill, to the northward of the hospital; which would be supplied with water from a reservoir made in the ad­jacent low ground. This would be replenished twice in twenty-four hours by the tide, by means of an open canal, or culvert, communicating with the reservoir. The small engine might be placed near the other, the pump well being supplied with water from the collect, conveyed in a culvert or pipes. The following calculations of the dimensions of the larg­est engine, will be found sufficiently correct, to ena­ble you to form a tolerable idea of the annual ex­pence attendant on it. Admitting the quantity (as before calculated) to be sufficient, we find that 2,200,000 gallons, or 359,640 cubic feet must be daily raised. Supposing the engine to work 16 hours out of 24, we have 22,477 feet to be raised every [Page 16] hour, or nearly 375 every minute, estimating ten strokes to be made in a minute, each stroke must yield 37 1-2 feet; but as pumps generally fail in pro­ducing the calculated quantity, say 40 feet per stroke; and if the lengths of the strokes are 8 feet, it will re­quire a pump of 30 27-100 inches diameter; but a pump of that dimension would not answer in prac­tice; it will be necessary therefore, to diminish the diameter and increase the number of pumps; six of 12 3-10 inches will be equal in area to that before-mentioned. As the water would be raised about 50 feet, the weight of the column would be 15613 lb, which would require a cylinder of 44 2-10 inches di­ameter (allowing the active power of Mess. Bolton and Watts engines to be 8 lb on every circular inch) such an engine would consume about 330 lb of coal per hour.

HAVING thus given you every information neces­sary to be known for your guidance, I shall conclude by remarking, that my objections to the Collect (be­ing founded on the doubts I entertain of its efficien­cy to supply the annual increasing demand of this improving city, and to the contamination its waters will be subject to) will be done away altogether, when it shall be made to appear that they are groundless; in such a case, there can be no question which plan is most eligible as it respects the time and expence of execution.

The Hon. RICHARD VARICK. New-York, March 14, 1799.