DOCUMENT NO. 2. BOARD OF ALDERMEN, MAY 14, 1838. The following Communication was received from the Water Commissioners, relative to the Croton Aqueduct, which was ordered to be printed and placed on file. THOMAS BOLTON, Clerk. To the Honorable the Common Council of the City of Neui York: The Water Commissioners beg leave respectfully to repre- sent: That, in their semi-annual report of the 1st of January last, they presented to the Common Council, their views on the subject of carrying the Croton water over the Harlaem River, and for the reasons therein set forth, they unanimously decided to cross the river with iron pipes, on a properly constructed bridge, leaving an opening, or arch way, sufficient in their opi- nion for all useful purposes of navigation. A plan and esti- mate of the cost accompanied the report. At the same time, Doc No. 2. 26 in order that the great saving in the expense of the project pro- posed and adopted by the Commissioners, might be seen, they submitted a plan, foi' crossing the river with an aquedect on a regular inclined plane, upon a high bridge of 131 feet above tide water, at an expense of $935,745, while the plan recom- mended by the Commissioners, for crossing the river on a low bridge, with iron pipes, would only cost $426,027, making a difference in favor of the latter of $509,718. The subject was referred, in the Board of Aidermen, to the Committee on " Roads and Canalsand the Commissioners, with the Chief Engineer on the works, were invited to attend several meetings of the Committee, when the necessary expla- nations were made, and the reasons in favor of the plan adopt- ed by the Commissioners freely communicated. A majority of the Committee, however, deemed the plan proposed by the Com- missioners, injurious to the navigation of the river. In order to obviate this objection, as far as consistent, the Commissioners proposed to leave an open archway of 120 feet in width, instead of 80 ; and 65 feet in height, instead of 50 ; which would still make the difference in the cost, in favor of the low bridge, $459,718. On the 23d day of April last, the Committee on " Roads and Canals" submitted their report to the Common Council, favoring the construction of a high bridge, at an expense of nearly half a million of dollars more than the plan proposed and adopted by the Commissioners. That report is still before the Com- mon Council, unacted on. The Commissioners feel themselves justified in taking exceptions to some parts of this report, as they think statements are made, and conclusions drawn from them, not warranted by the facts of the case. The Committee, at page 619 of their report, introduced the estimates of Major Douglass, for crossing the river, both by aqueduct and by sy- phons, which shows a difference in favor of the syphons of only $51,370, while the estimates of Mr. Martineau, for crossing the river with syphons, which was adopted by the Commissioners, when contrasted with the estimates of Mr. Douglass, for the 27 Doc. No. 2. high bridge, (Mr. Martineau having presented no estimate for the said bridge,) makes the difference in favor of the syphon $227,912 62. At the same page, the Committee observe:- " This same bridge, which was estimated to cost $415,650, is now estimated to cost $935,745," and they deem it " worthy of consideration, whether, with such discrepancy in the esti- mates, it would not be well to make more thorough and satis- factory estimates, before commencing the work." To this, nei- ther the Commissioners or Engineers can have any objection, if it should be deemed necessary by your Honorable Body. They, at the same time, think they have already given, in their report of the first of January last, satisfactory reasons for the discrepancy alluded to, which may be found at page 380 of the said report, where they observe, " The sum required is more than $3,000,000 over any of our former estimates, and can only be accounted for by the fact, that the Engineers, originally employ- ed, did not possess the means of testing their calculations, by the actual cost of the work under contract, as we have been able to do, <fce." These reasons, the Committee have not al- luded to, not having deemed them worthy their attention ; but, had they, or either of them, travelled over the line of Aqueduct before and since the commencement of the work, the Commis- sioners think they would have been better enabled to estimate the cause or discrepancy than they now are, in a work of greater magnitude than is to be found Jn this or any other country. At page 624, the Committee state, that the receiving reser- voir is at 86th street, and until the water reaches this, it is not proposed to draw off any water for the use of the city above that street. No benefit, therefore, will be derived from the pro- ject, to the upper parts of the island, while at the same time, they would be taxed to pay the interest on the debt, &c. This conclusion is by no means correct; the Committee might, with the same propriety say, no provision is made for supplying that part of the city, between the receiving reservoir at 86th street, and the distributing reservoir at 34th street, or between that Doc. No. 2. 28 and the Battery. The duty of the Commissioners is, to bring in the water, not to distribute it. The water will stand at 86th street, about 120 feet above tide, and may be distributed from the receiving reservoir, to a large portion of the upper parts of the city, as high as the attics of the buildings, and it is believed, there is a very small portion of the land on the island so high, but that they may receive the water from this reser- voir, in their basement at least. If that part, or any other part of the city is not supplied with water, therefore, it will not be the fault of the Commissioners, but of those whose province it is to distribute it by pipes. At page 620, and at several other parts of the report of the Committee on " Roads and Canals," it is asserted that " the na- vigation would be obstructed for every thing, except boats and vessels without masts." The general assertion by the Committee " that an archway of 65 feet in height, and 120 feet span, will not admit vessels with masts, to pass through it," is what we had no right to ex- pect. It must be known to the Committee, as it is to every per- son having any knowledge of the vessels navigating our rivers, that there are many of them which could, with perfect ease, pass through this archway. The two masted craft employed in trans- porting manure, have masts from 35 to 45 feet in height. Near- ly all the market boats, as they are called, of from 40 to 50 tons, have masts measuring, from the keelson up, from sixty to sixty-five, as the Commissioners are informed. There are, however, no doubt, several hundred vessels with masts, now navigating both the North and East Rivers, that could pass through an arch of 65 feet in height, and any of the steam- boats, with their towboats, would find no manner of difficulty in the passage. The large sloops of 90 or 100 tons, with masts of 80 feet in height, would not be able to pass ; but, if the contemplated canal shall be cut sufficiently wide and deep, and if McCombs Dam shall be removed, and some parts of the channel excavated, then, and in such case, these large vessels may come from the North River as far as the bridge, and also 29 Doc. No. 2. from the East River to the bridge. It appears to the Commis- sioners, however, quite problematical, to say the least of it, that the Harlaem River will ever be made navigable for any but small vessels. First, there is McComb's Dam to be removed. The act authorizing its erection, makes it the property of Robert McComb, his heirs and assigns forever ; and how are they to be deprived of it, as a vested right ? Second, the channel of the river is full of sinuosities and curves, and varies from twenty to five feet in the deepest parts of it. To make it straight is impossible, and to deepen it will be attended with great expense ; add to this, the contemplated canal, through marble rock and salt marsh, with the removal of a portion of the dam, and we have a work that cannot be effected for less than half a million of dollars. The act incorporating the Harlaem River Canal Company, only contemplated an improvement of the naviga- tion, * so as to afford to vessels which shall traverse the land canal, an easy navigation from Spuyten Duyvil Creek to and along Harlaem River to the East River," and the Committee on " Roads and Canals" of the Board of Assistants, in their report of the 22d January last, at page 431, confine the whole object of improvement to obtaining a draft of water amply sufficient for a passage through the river, "not only for ordinary steam- boats, but also such lake boats as will find their way to our city, through the enlarged Erie Canal;" and at page 436, " to establish a direct communication for steamboats, and other ves- sels, between the East and North Rivers, and affording a de- lightful and cheap aquatic excursion, to a numerous class of our citizens." At page 437, they say, " here may basins be con- structed, for all our river and lake craft, and if it is found ne- cessary for large vessels to lay here, or to repair, in the section of the river between Harlaem and McComb's Dam, the water is sufficiently deep." The improvement of the navigation, therefore, as contem- plated by the Engineer who made the survey, and by the Com- mittee who projected the plan, only extended to the opening a navigation for steamboats, and vessels navigating the canals; Doc. No. 2. 30 and the plan for crossing the Harlaem River, as proposed by the Commissioners, not only gives the facilities contended for, but increases them. At page 624 the Committee say, "the rapidity of the cur- rent through the archway, for at least half of the time, would be such as to make it dangerous to pass through, even if the height was sufficient." If the rapidity of the current, through an opening of 120 feet, which is greater than the channel width of some parts of the river, would make it dangerous to pass, what would be the effect of a passage through the draws of the five or six bridges, particularly through the contemplated opening in McComb's Dam, which it is understood is to be but from twenty to thirty feet in width? The draw in the Harlaem Bridge is not to be less than twenty-five feet, by the act; and the bridge now in progress, for the use of the inhabitants of Harlaem and Morri- sena, is carried out, in solid abutments, from both sides of the river; and will have the same effect upon the rapidity of the tide as McComb's Dam, and much greater than the low bridge, with an opening of 120 feet, as proposed by the Commissioners. Instead, therefore, of the decreased depth of the river, by the erection of the low bridge, as supposed by the Committee, we concur with the Committee of the Assistants, " that this river will be restored to its original depth, by the proposed work, from the force of the current, is the general opinion of all who have considered the subject." The answers made by the Committee, to the specific reasons offered by the Commissioners in favor of the plan by syphons, has not been attended to, as they have presumed your Honora- ble Body will contrast the reasons with the answers, and de- cide them on their merits; but the Commissioners feel them- selves called on to notice the observations of the Committee, as to the third reason offered by the Commissioners. The Com- missioners only stated the fact, that the experience in sinking piers, in so great a depth of water and mud, in order to reach the rock bottom, being very limited, and their great number 31 Doc. No. 2. and immense height, from the rock to the spring of the arches, although their construction is practicable, it must be attended with many unforeseen difficulties and casualties, &c. (see Doc. 55, p. 372); and the Committee admit, that they were informed by Mr. Jervis, that he did not consider there was any serious difficulty in the erection of the high bridge. (See their report, p. 622.) With these opinions before them, that the Commis- sioners considered the measure practicable, and that the Chief Engineer did not consider there was any serious difficulty in the way of the erection, the Committee seem to understand the fact of limited experience in sinking piers, of the description al- luded to, as applicable to the whole work on the aqueduct, and accordingly say, " If there is a want of experience in those em- ployed by the Commissioners, in working on the Croton Aque- duct, it certainly is not to be supposed that men of competent abili- ties and experience can not be found to undertake and complete the work." There are but two works in this country, known to the Commissioners, in which piers have been sunk, in about the same depth of water and mud, as those required for the aqueduct bridge over the Harlaem River, viz.: the bridge for travelling over the Schuylkill River, at Philadelphia, and that in progress, for crossing the Potomac River with the Alexandria and Chesa- peake Canal. With a knowledge of this fact, had they not good reason to think the experience in this description of work limit- ed? But the Committee have referred to the London Bridge, the bridge over the Potomac, as well as several other works in our own country, of a similar character, all requiring as much experience and skill as this work, &c. (p. 621.) Where these other works of a similar character are situated, the Committee have not deemed it necessary to say. Those they have quoted, however, differ materially from the high bridge for crossing the Harlaem River. The piers of the London Bridge, from the bottom of the foundation to the top of the parapet wall, is about seventy feet in height, while the high bridge is 163 feet, nearly double; and the piers of the bridge over the Potomac, are about fifty feet, or about the one-third of the height of the aforesaid high bridge. Doc. No. 2. 32 The Commissioners have deemed it their duty to state fur- ther, that they were directed by the Act of the Legislature, passed the 2d of May, 1834, to adopt a plan for supplying this city with water; which plan, if approved by the Common Coun cil, was to be presented to the electors ; and, if adopted by them, it was to be carried into effect, " with such immaterial altera- tions as may be necessary." The plan submitted and adopted, both by the Common Council and by a majority of the electors, contemplated crossing the river by iron pipes, or an inverted syphon, as the following extract from the report will clearly show: "Crossing Harlaem River by aqueduct, and by wrought iron pipes, or inverted syphons, as to cost. Estimate by J. Martineau, for wrought iron pipes$ 187,737 62 " by D. B. Douglass, by high arches and aqueduct ...... 415,650 00 Differedpe ,.in favor of an inverted syphon $227,912 62" The difference in the cost of crossing the river by a pipe of the description alluded to, compared with that of an aqueduct, is so considerable that, in the opinion of the Commissioners, it ought to be adopted. (See Doc. 44, p. 364.) At page 368, they say, " the river is to be crossed by inverted syphons, &c." and in bringing together the estimates of the two Engineer^, the saving, by crossing the river by syphons instead of aque- duct, is deducted from the average amount of cost; clearly showing, that throughout their report, the Commissioners had in view the propriety of avoiding the heavy expense that would be incurred, if the plan for a high bridge and aqueduct of ma- sonry was adopted. The quotation from the report of the Com- missioners, referred to by the Committee on " Roads and Ca- nals," at page 619, was not given as the opinion of the Com- missioners, but as the opinion of Major Douglass; and forms part of the synopsis of the report, made by that gentleman to the Commissioners. 33 Doc. No. 2. The Commissioners are of opinion, therefore, that an impor- tant part of the plan adopted by the Common Council, and ra- tified by a large majority of the electors of this city, was the crossing of the Harlaem River by inverted syphon; and it then remains for the Common Council to decide, whether, under the circumstances of the case, it is competent to direct so material an alteration in the plan, not called for by any adequate consi- deration of usefulness, and thus add to the expense of the pro- ject more than half a million of dollars, without the sanction of the electors in the same manner as that provided for in its adoption. Whatever may be that decision, the Commissioners feel they are bound to comply with its direction. They would respect- fully urge, however, a speedy decision on the question, in order that this part of the work may progress in the same order, and with the same speed, as the other parts. The crossing of the Harlaem River, even by the plan proposed by the Commission- ers, is a work of great magnitude, and its c^B^ncement ought not to be delayed a moment more than whaMrabsolutely necessary. The time already elapsed since the subject was presented to the Common Council, has tended to embarrass the operations of the Commissioners, in a measure, by depriving them, during their late letting to contractors, of placing this im- portant part of the work in a progressive situation; and, if longer delayed, will materially interfere with the further opera- tions of the work; particularly if the expensive project should be adopted, which will require one or two years more to complete, than the plan recommended by the Commissioners; they ear- nestly request, therefore, that your Honoral le Body will give them the necessary instructions, at the earliest day practicable. All which is respectfully submitted. By order of the Board, Orfce of the 'Water Commis- sioners, May 8th, 1838. STEPHEN ALLEN, Chairman.