lons per diem. Fourth, the main Croton, including the east, west, and middle branches, which gives 12,695,480 gallons per day, making a total of 30,460,160 gallons every twenty-four hours, that will enter the confluent reservoir, if permitted; and, if we add to this the quantity produced by the river Cisco, we have 32,503,760 gallons runing water for daily use, if required. These several streams were gauged on the 4th, 5th, and 6th of September last, at a time when no rain, of a day's continuance, had occurred for about two months; and the opinion of the inhabitants was, that the streams were as low as they had ever been, except at a remarkable drought in 1816. To meet a like occurrence, should it again happen, it is proposed to deduct one-fifth from the foregoing results, which will reduce the quantity flowing on to the city to 26,002,008 gallons per day. From the confluent reservoir the water is to be carried in an aqueduct of masonry, the construction of which is particularly described in the report of the engineer, to the head-waters of the Sawmill river, which will require a deep cutting of about three miles, averaging 38 feet in depth and 55 feet at the dividing ridge. This is considered the principal difficulty in the location of this route. Twelve miles from the confluent reservoir, the engineer points out a favorable position, of 258 feet above tide, for a storing reservoir, should it be required or deemed at all necessary. For the next fifteen miles the ground goes off at a gentle slope, requiring no cutting or filling to any extent, or extra work of any kind, except in one or two instances. The entrance to the valley of Tibbit's brook requires a cut through the dividing ridge of 12 chains, or 792 feet in length, and 22 feet deep on an average, chiefly in rock; or it may be tunnelled, which will shorten the distance 50 or 60 feet. At this position another favorable place is proposed, 147 feet above tide, for a storing reservoir, if required. From this the route passes on the Harlem river, without any material obstruction to the work, either by deep cutting or high embankments. The river is to be crossed by an aqueduct bridge of 18 chains, or 1,188 feet in length, and consisting of nine plain semicircular arches; the height, to the water line of the aqueduct, will be 126 feet. On the aqueduct crossing the bridge, and entering the island of New-York, it proceeds to a receiving reservoir, located, by the profile accompanying this report, between the Ninth and Tenth Avenues and One hundred and thirty-third and One hundred and thirty-seventh-streets, at a height of about 123 feet above tide; and from thence, by conduit pipes, to reservoirs, termed by the engineer, equalizing reservoirs; one on One hundred and fifth-street, between the Eighth and Ninth Avenues, and the other on Sixtyninth-street, east of the Eighth Avenue; and finally, to a distributing reservoir, at the intersection of Thirty-eighth-street and the Fifth Avenue, three miles from the City Hall. The distributing reservoir is calculated to contain between fifty and sixty millions of gallons, and the water to stand in it at the depth of 20 feet, and 117 feet above the tide. The distance from the confluent reservoir to the receiving reservoir, at Manhattanville, is 37 miles 52 chains, and from that to the distributing reservoir, on Thirty-eighthstreet, is five and a half miles, making the whole distance of this route about 43 miles from the confluent reservoir, at Mechanicsville, to the distributing reservoir, in the city of New-York. The cost of the works is estimated at the sums following: For the conduits to the confluence reservoir, from the Muscoot, Cross river and Beaver dam, $761,000 Indemnity for water rights,.. ... Contingencies, 43,500 50,000 Total expenses of the water of lower Croton,..... $854,500 Amount brought forward,..... 8 Constructing confluent reservoir, channel way, &c.... Expense of the remaining 31 miles, viz.- 558,000 $191,000 733,420 576,000 1,020,000 200,000 Iron main at $100,000 per mile, 550,000 Contingencies, 325,067 Damage to land and water rights,...................... 100,000 2,962,317 $5,827,237 Total cost of bringing the water to the city, It may be proper to observe here, that the quantity of water may be reduced or increased at pleasure, by using or not, as the case may be, any or all of the streams leading to the confluent reservoir, as shall be deemed necessary to furnish a full supply. Thus, if we exclude the water of the upper Croton branches, viz. the west, middle, and eastern branches, which will require to be brought in iron conduits for about fourteen miles, we shall still have a daily supply of about sixteen million of gallons, and a reduction in the expense of $1,277,000; leaving the actual cost of the project at $4,550,237. Second, the Hudson River Route. It is proposed, on this route, to build a dam across the main Croton, about one mile below Mechanicsville, and a mile and a quarter below the confluent reservoir. The height of the fountain head thus formed, will be about 175 feet above tide, and the quantity of running water which will come to this reservoir, including the discharge from the Muscoot river, will be 44,120,924 gallons daily. The location of this route, until it penetrates the valley of the Sawmill, is carried along the hill side of the Hudson and Croton rivers; the line follows the north bank of the Croton to Garritson's mill, when it crosses the river on an aqueduct of 85 feet span, to the south bank, where an arch must be thrown over the road in order to admit the passage of travellers. A number of culverts must be built, and several excavatious made, of 20 to 23 feet in depth, on this part of the line. Near the mouth of the Croton, a work of considerable magnitude occurs, where the ground will have to be excavated to the depth of 35 feet at the summit. After leaving the valley of the Croton, near Sing-Sing village, another deep cutting occurs, of 36 feet at the summit; and in crossing the chasm, or gap, at Sing-Sing hill, a culvert of 60 feet span will be necessary. The route then proceeds nearly on a line with the turnpike road, without any material excavations or embankments, for 19 miles from the Croton reservoir to Sleepy-Hollow. In crossing this hollow, an aqueduct of five arches, of 70 feet span, and 500 feet in length including the wings, and 60 feet in height to the water line, will be necessary. Two miles below this, at Tarrytown, a cut of 15 feet, and about two miles further on, another, of 26 feet, will be required. Several heavy culverts must be constructed, one of which, in the vicinity of Greenburgh landing, must have a span of 20 feet. Here the route leaves the line of the turnpike road and inclines east, towards the valley of the Sawmill river. In order to enter this valley, a deep cutting will be necessary, of 45 chains, or 2,970 feet in length, and averaging 37 feet in depth chiefly rock. After entering the valley, the Sawmill river has to be crossed, which will require an aqueduct of three arches with 60 feet span, making the length, including wings, 250 feet, and the height above the river, 36 feet. The Hudson river route, and the Sawmill or interior route, now take the same line to the city. The former, however, is considerably lower in its grade than the latter, and consequently the magnitude of its works will be increased. The Harlem river is to be crossed by both routes, in the same manner, to the receiving reservoir, between the Ninth and Tenth Avenues and 133d and 137th streets, on the island of New-York. The distance from the dam, on the Croton river, to the distributing reservoir, at the intersection of 38th street, is nearly 47 miles. The expense of constructing the Hudson river line will be as follows: For cutting and filling, including the dam of the Cro- $674,651 812,000 Channel way for aqueduct, or open conduit, 35 miles As the corporation are in possession of a survey and map of the country, embracing the Bronx river and its sources, the Commissioners have not deemed it important to spend much time in the examination of that river, with the object of supplying the city with its waters; particularly, as the running water to be obtained, it is believed, would barely be sufficient for present purposes, with out reference to the future; and their time being limited to the month of November, when, by the act under which they are appointed, the report to the Legislature is directed to be made, and the examination to cease, they have deemed it more profitable to lend their whole attention to a source of supply, where the adequate quantity may be obtained at all seasons, both for the future as well as for the present. Some attention, however, has been given to the subject, as may be seen by the report of the Engineer. In order to test the correctness of an opinion, that the Harlem river possessed the requisite power to raise the water to a sufficient elevation on New-York island, a calculation has been entered into, the result of which is, that the whole power of the river would only raise to the requisite height, 4,939,000 gallons in 24 hours, being about two millions less than the present wants. By a reference to the map, it will be seen, that a line has been run, commencing at Popham's factory on the Bronx river, where a head of 142 feet above tide was gained; from whence the line continues down the west side of the river, taking the same ground, from the vicinity of Fordham's church, as that occupied by the routes from the Croton; the ground is by no means unfavorable, but, in crossing, an aqueduct of 740 feet, at an elevation of 57 feet, [Assem. No. 15.] 2 |