690 



NEW YORK STATE MUSED M 



of ground water in about fifteen hundred wells included in 1000 

 square miles of territory. 



At a test of the old driven- well plant at Spring creek, made from 

 October 22 to November 20, 1894, water was pumped at an average 

 rate of 4,091,551 gallons in 24 hours. The elevation of the under- 

 side of the discharge valve of the pump was 12.3 feet above datum. 

 On October 22, at the beginning of the tests, the average elevation 

 of the water in the wells was 4 feet below datum. The quantity 

 pumped in 24 hours, on October 22. was 4,488,275 gallons. On 

 November 20, the date of the conclusion of the test, the elevation 

 of water in wells was 7.7 feet below datum, and the quantity 

 pumped on that day in 24 hours was 4,112,663 gallons. The total 

 quantity pumped during the entire period from October 22 to 

 November 20 was 122,746,525 gallons. The taking of this quantity 

 of water from the wells resulted, therefore, in lowering the ground 

 water a total of 3.7 feet. 



A new driven-well plant at Watts pond was subjected to a test 

 of capacity extending continuously from January 3 to February 2, 

 inclusive. In 1895 a rather extended series of tests were made 

 of a number of the wells of the Brooklyn water supply in order 

 to determine the yield as well as the extent of the underground 

 supply. The following particulars of these tests have been derived 

 from Mr De Varona's report, as contained in the annual report 

 of the commissioner of city works for the year 1895. 



The flowing wells at Jameco were tested from January 3 to 14, 

 inclusive. During this period the wells were operated singly and 

 in groups of 2, 3, and 4, in all possible combinations, and observa- 

 tions were taken to determine the elevation of the ground water. 

 Upon completion of the tests a series of observations was taken, 

 extending to January 30, to determine the normal water level. 

 It was shown that the average yield from one well alone was 

 only 1,000,000 gallons daily, decreasing pro rata up to a total 

 yield of 3,500,006 gallons daily when four wells were in 

 operation. The lowering of the ground water was approxi- 

 mately 5 feet when pumping 1,000,000 gallons, increasing up to 

 approximately 10 feet when pumping at the full capacity developed 

 of 3,500,000 gallons. In this connection it is stated that the water ^ 

 in these test wells is found to rise and fall directly with the tide, 

 thus rendering it difficult to state with accuracy the full effect of 



