Overflowof Croton Water.
From April 25, 1909, to May 1 almost 10,000,000,000 gal. of water poured over the spillway of the Croton dam uselessly into the Hudson— enough to have supplied the wants of the city for a month, and the flow has not been greatly diminished since that time. Between November, 1907, and June, 1908, approximaeely 80,000,000,000 gal. ran to waste over in the same spillway—sufficient, used in connection with the natural flow of the Croton and its feeders, to have supplied the city with water for almost five years; or, without drawing a drop from the existing storage, it would have furnished supply for eight months. The lowest amount wasted was that of May 10—232.000,000 gal.; the highest, that of May 1—1.161,000.000 gal.; that of April 301,014.000,000—was a close second. The total tints lost—0,166,000,000 gal.— would have supplied the boroughs of Manhattan and The Bronx for 29H days—the estimated daily consumption in these two boroughs being 324,000,000 gal.
1 his wasted water would have come in most serviceably last summer and fall, when, although billions of gallons had run unused into the Hudson—the total volume of water in storage in the different Croton reservoirs fell below the normal danger point to 38,000,000,000 gal., of which about 20,000,000,000 gal. were practically useless, except for putting out fires, being a compound of mud, silt, sediment and decayed vegetable matter. Hence, a dry or snowless winter and a dry spring—and last winter partook somewhat of that character, although the rainfall has possibly supplied the want of the melting snow—might prove a very serious matter for a large portion of New York city—one that, under present conditions, cannot be remedied before the Catskill supply is available, and that cannot be before 1917, if then. For several years, therefore, the city’s condition as to its water supply is risky. The risk, however, can be in large measure, if not altogether, averted, not only by metering every tap, but, also, by stopping the underground leakage. The stopping of the waste at the Croton dam would constitute a large factor of safety. At present the new Croton system, including the old Croton and Muscoot dam. with its subdivisions, is as follow’s: New Croton Amawalk. with Kirk Lake and Mahopac. Cross River. Titieas. Croton Falls main dam. with West Branch or Carmel, with Lake Glencida, Barrett’s pond. Byrd’s Corners, lake Gilead, Middle Branch. East Branch and Bog brook. These all empty unitedly into the new Croton reservoir, which was completed in 1905. From it two aqueducts convey the water to the city. Below Croton Falls, some 18 miles above the main dam, the river receives the waters of the Amawalk reservoir, the Titicus reservoir, and the new Cross River reservoir, completed only last year. In the rear of Amawalk and floufing into it is lake Mahopac—a large body of water, which private ownership has caused to be restricted for public use to 5 ft. Above the falls the river divides into the East, Middle and West branches. The last at Carmel dam, receives the waters of a half dozen small lakes, as well as those of the Boyd’s Corners reservoir—one of the oldest of the large storage-receptacles. The East Branch likewise receives the water of several small lakes and reservoirs. From the headwaters of the three branches to the new Croton reservoir, the fall is considerable. The new Croton dam is 200 ft. above sea-level. Amawalk, the highest of the feeders below the falls, is 402 ft. in altitude. The West Branch, which receives its water from the highlands over towards the Hudson, shows the highest altitude, Carmel dam being 504 ft. and Boyd’s Corners reservoir 593 ft. above sea-level. Middle Branch reservoir has an altitude of 373 ft., and East Branch and Bog Brook combined an altitude of 417 ft.
The following dates and figures show the date of the completion of each reservoir, its area of tributary water shed in square miles, the elevation of its spillway above sea-level and its total storage capacity in millions of gallons: Boyd’s Corners dam.—1873: watershed area, 21.43 sq. miles; elevation, 593 ft. capacity, 2,727. White pond.—1879 to 1879; watershed area, 97; elevation, 830.5 ft.; capacity, 200,000,000; West Branch, or Carmel.— 1895; elevation, 503 ft.; watershed area, 19.51; capacity, 10,668,000. Barrett’s pond.—1870; watershed area, 57; elevation, 779 ft.; capacity, 170,000,000. Lake Gleneida.—1870; watershed area. 68; elevation, 505 ft.; capacity, 165. Middle Branch.—1878; watershmed area, 20.51; elevation, 372 ft.: capacity, 4,155. East Branch.— 1891: watershed area, 73.23; elevation, 417 ft.: capacity, 5,243. Bog Brook.—1891; watershed area, 3.67; elevation, 417 ft.; capacity, 4,440. Amawalk.—1847: watershed area, 18.32; elevation, 400 ft.: capacity. 7,086; Kirk lake.— 1870; watershed area, 2.84; elevation, 583 ft.; capacity, 565 gal. Lake Mahopac.—1870: watershed area, 2.36; elevation, 660 ft.; capacity, 575 gal. Croton Falls, main dam.—To be completed by the fall; watershed area, 23.39; elevation, 310 ft.: capacity, 14,865 gal. Lake Gilead.—1870; watershed area, 62; elevation, 497 ft.: capacity, 380 gal. Diverting dam.— Watershed area, 6.40; elevation, 310 ft.; capacity, 888. Titicus.—1893; watershed area, 22.80; elevation, 325 ft.; capacity, 7,617. Cross River.—1908: watershed area, 28.58: elevation, 330 ft.: capacity, 10,923. New Croton.—1905; watershed area, 129.00; elevation, 200 ft.; capacity. 33.815. The total reservoir capacity, thereiore, is 104,442,000,000 gal., or till the Croton Falls reservoir is finished, as it is stated it will be, in time to receive the flow from this fall’s rains, 89,577,000,000 gal., of which, on an emergency, probably one-fourth would not be fit to drink without filtration.
Competent engineers, however, are of the opinion that, although past a certain point the development of storage reservoirs cannot be pushed without impairing the water supply, it has been estimated that the present watershed could bear extension up to about 135,000,000,000 gal. It has, therefore, been proposed to convert the Patterson valley along the East Branch into a reservoir to hold 20,000,000,000 additional gallons. This valley extends north from Putnam county over the line into Dutchess, and marks the extreme-northerly region available for the purpose. It has been already surveyed, and engineers estimate that it could be made ready for the reception of water in two years’ time by the construction of an earth and masonry dam of moderate height. A reservoir averaging from 14 to 18 ft, in depth could thus be obtained. This, of course, would not take care of the entire overflow, for the other independent reservoirs are iust as full; but it would have the effect of lessening the present waste by a considerable amount, and, furthermore, it would bring the total storage-capacity for the watershed up to 124.000.000,000 gal. In case of an emergency the 20,000,000,000 gal. would supply the city at the present rate of consumption 324.000,000 gal. a day. for practically two months’ time. The cost, including the relaying of 12 miles of railway, would be comparatively small— about $3,250,000, and if the water used every day by the city should reach the present capacity of the Croton reservoirs, before the Catskill supply is available, the extra 20.000,000.000 gal. would prove a godsend.