The Largest Well in the World--Capacity 1,000,000 Gallons of Water per Day.
One of the grand necessities of the Prospect Park, Brooklyn, N.Y., that of providing for a continual supply of water for all the purposes of the Park developed itself, as the Commissioners progressed with their stupendous undertaking. Mr. Stranahan, the President of the Board, after carefully weighing the cost, the practicability, and importance of having an independent water supply for the Park, advised the Commissioners of the plan which had suggested itself, and the calculations which had been made by the engineers relative to the project, and the work was commenced, the first idea being to secure at least a partial supply of water by means of a well constructed in the Park. The subject was thus treated in the last annual report of Mr. C.C. Martin, the engineer in charge:
"This well has been located on the south side of Lookout Hill, near the lake, and work was commenced upon it late in the season. After a careful consideration of various methods for sinking the well, it was decided to build the wall and then to excavate the material from within, trusting to the weight of the wall to force it down. Sixteen feet of the wall were laid securely bolted together, before the excavation was commenced. A derrick with a boom fifty-five feet in length was set up near the wall, so that the sweep of the boom commanded the interior of it. Iron buckets containing fourteen cubic feet each were obtained, and a six-horse power hoisting engine purchased. With these appliances the excavation was commenced, and carried on with slight interruption until the work was suspended on account of the frost."
The well is now completed, and is one of the most important features of the Park. It is worthy to rank as a feat of engineering skill with, any of the great works of modern times. The Commissioners decided to put its powers to the test yesterday afternoon, but owing to the unpropitious weather of the forenoon the trial was postponed. Nevertheless, Commissioners Stranahan, Fiske, and Haynes, with Mr. Martin, engineer in charge, and Mr. John Y. Culyer, his assistant, were at the well. During the last summer some difficulties were encountered in the sinking of the wall, which were set down by superficial observers as the utter failure of the enterprise. Mr. Stranahan received but little encouragement from his fellow Commissioners, some of whom had never seen greater works of engineering than the construction of street sewers. He assumed the responsibility of seeing the work through, feeling that the whole thing depended entirely upon the ability of the engineers, in which he had abundant faith. All obstacles were surmounted; the work proceeded and the well is now finished, and so far as is known, is understood to be the largest one in the world.
The outer wall is fifty feet in diameter, two feet thick, and fifty-four feet high. The inner curb, or wall, is thirty-five feet in diameter and two feet thick, having a depth of ten feet. The masonry, as seen from the top of the structure, is a marvel of neatness and solidity. The water surface in the well is thirteen feet above high-tide level, and the depth of water in the well is fourteen feet. The pump foundations are entirely independent of the walls. This plan was adopted so as to obviate any possible difficulty which might arise from displacement. The pump is the Worthington patent, and, with a pressure of forty pounds, is capable of raising one million gallons of water every twenty-four hours a height of 176 feet, and is competent to a lift of 180 feet.
The boiler house is a neat, pressed-brick structure trimmed with Ohio stone, standing on the surface near the mouth of the well. The interior of the well is reached by a spiral stairway built in the wall, and commencing in the boiler house. In this way the engineer is able to reach the pump. It is a fact worthy of notice in connection with the construction of the wall, or rather the sinking of it, that the outer wall rests upon four feet of wooden cribwork, two feet thick, and having an iron shield. The inner wall is built upon a similar crib only two feet deep, also shielded with iron.
The Commissioners were led to the construction of this well in presence of the danger at any time of some accident taking place in connection with the Brooklyn Water Works which would render it necessary for the Water Board to cut off the Park supply so as to secure the citizens from suffering. This well has more than the necessary capacity to supply the Park abundantly with water, yielding most when most is needed. This is established by the discovery that the time of drought from which the well is, or may be, likely to suffer, occurs in the Fall. Besides these facts, it further appears that in order to furnish the supply of water to the Park the Water Board would have to go through the process of pumping their water twice to convey it to the required elevation, equal to 225 feet from its original level.
The work of the well will be to supply the pools at an elevation of 133 feet. From the pools the water is conducted to the lake. Besides this, there is an independent connection with the lake by which, as necessity may suggest, the water can be directed to the lake, a lift of only seventy feet. The lake, when completed, will occupy an area of fifty acres, which will be kept continually supplied with fresh water, the arrangements being such, or to be such, as will insure a permanent change of water, and prevent any of the evils that may arise from stagnancy. The well is fed from the earth, consisting of a circuit of two miles, with a fall of five feet to the mile. For this reason it does not appear easy to exhaust the supply, as when the water is pumped out to four or five feet from the surface of the well it is replaced at a rate equal to the demand. Every allowance has been made for evaporation from the lake and pools, and the supply is regarded as inexhaustible. Another important fact here suggests itself; that is, that sufficient rain falls during the season in the area of two miles around the well to make the supply perennial. The Prospect Park well is a credit to Brooklyn.--New York Times.