THE CROTON WATERSHED SUPPLY

THE CROTON WATERSHED SUPPLY

If the prophesyings of alarmists on all sides are to be believed, long before the Catskill supply is distributed in New York city, there will be a water famine. According to some engineers, that famine should have taken place by the end of 1907. It did not materialise, nor did it materialise, notwithstanding the fact during the late fall and the winter months of 1907-08 more than 70,000,000,000 gal. of water have passed over the spillway of the Croton dam. In November last all the upper reservoirs of the Croton system were filled, and the water rose to the crest of the dam’s 1,000-ft. spillway, the stream increasing in capacity till it reached a depth of 1 ft. for the whole length of the spillway, and the flow has continued to a greater or less degree without intermission up to the present time. During the recent heavy rains of May, the flow, which (as represented in the accompanying illustrations reproduced from the Scientific American) was about l-in. was increased to 6-in. The Croton watershed itself is situated east of the Hudson river and extends from the great dam, which is built about 2 1/2 miles of the point where the Croton river discharges into the Hudson, is made up of rolling land, chiefly agricultural and pasture, with very little forestarea and with no large towns. Its total area is 360.4 sq. miles. There are nine reservoirs 011 the system, and six natural ponds have been adapted to the purpose of storage. The Cross river dam, which has recently been completed, has a capacity of 10,308,000,000 gal. The Croton Falls reservoir, with a capacity of over 14,000,000,000 gal. is being built. The most important reservoirs are the Amawalk, the capacity of which is nearly 7,000,000,000; the Carmel or West Branch reservoir, whose capacity is 10,000,000,000 gal.; the Titicus, whose capacity is 7,000,000,000 gal., and the new Croton reservoir, whose capacity is close upon 30,000,000.000 gal. The total available capacity of these reservoirs, when all are completed, will be 336,000,000,000 gal. daily through ordinary dry years. The present Croton reservoirs, the elevation and the capacity of each was as follows: Boyd’s Corners, elevation, 593 ft., capacity, 2,727,000,000 gal.; East Branch, Boybrook, 417 ft. 9,028,000,000 gal.; West Branch, 503 ft., 10,070,000,000 gal.; cross river, 330,100,308.000 gal.; Titicus, 325 ft., 7,167,000,000 gal.; Middle Branch, 372 ft., 4,005,000.000 gal.; Croton Falls diverting dam, 310 ft., 8,880,000,000 gal.; Croton Falls, 310 ft., 14,192,000,000 gal.; Muscoot (Amawalk), 400 ft., 7,678,000.000 gal.: Muscoot dam, 2,500,000,000 gal.; Old Croton dam—now submerged by the new Croton reservoir—capacity, 2,000,000,000 gal.; new Croton reservoir, 200 ft., 30,000,000,000 gal. The Cross river, the Titicus river, the east, middle and west branches of the Croton river, and the Muscoot river, with their accompanying streamlets, combined into the Croton river, make up the principal feeders of the Croton reservoir. The Croton river itself during thirty-six years from t869 to 1904 experienced two dry periods of eighteen years each, the first being the drier of the two. In the first period the annual average flow was 127,000,000,000 gal.; in the second, 165,000,000,000. In 1907 for the first eight months of the year the rainfall was only 28.1 in. —5 in. below the average. The heavy rains that set in about the middle of September and continued till the end of the year raised the total precipitation to 59.6—a figure exceeded only twice during the past forty years. In those late fall months and during the winter months of 1908 (as has been already said) 70,300.000,000 gal. of water have run to waste over the spillway of the Croton reservoir. Hence, has arisen the natural question as to whether it would not late been feasible and more economical to have constructed additional reservoirs throughout the watershed (among these the Quaker dam, which was begun, but never finished, owing, it was said, to the influence exercised by certain interested parties). By so doing and metering the city supply, it is claimed that the necessity for building the Catskill supply at a cost (as originally estimated) of $161,000,000—in reality it will be at least $200,000,000 —• would have been avoided. On the other hand, it is claimed that the cost of building the storage-reservoirs required to utilise the wastage over the spillway (409,000,000.000 gal.) during a period of forty years similar to those from 1868 to 1907 would be much greater than to have recourse to the Catskill supply. The expense would amount to $153,000,000. and, in return, only 47,000,000 gal. more would lxgained daily, while the Catskill supply would give 500,000,000 daily. This fact, however, is admitted by the engineers— namely, that, as there arc several points in the Croton watershed where a large amount of water could still be stored to advantage, additional reservoirs should be built. Another point, however, is ignored, or, at all events, relegated to the background—namely, that another very large saving in wastage could be avoided by metering the whole supply, which, with the gain from the additional storage already referred to, would bring the whole supply very far up towards the 500,coo.ooo promised by the Catskill supply.

Middle Branch Reservoir, Capacity 4,000,000,000 Gallons.Spillway of Croton Dam Only a Few Feet Less in Height than Niagara Falls.

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