PROBLEMS FROM DEVELOPMENT 125 



center of this cone of depression, in downtown Brooklyn, 

 was more than 15 feet below sea level. By that year, salt 

 water had moved in from Jamaica Bay and from the East 

 River and appeared in many pumped wells. 



Legislation passed at this time required permits for draft 

 of more than 100,000 gallons per day from new wells, and 

 these permits were issued with the proviso that water used 

 for cooling and air conditioning be returned to the same 

 aquifer through recharge wells. Since these regulations did 

 not apply to existing wells, the beneficial effect upon the 

 ground-water reservoir was delayed until a sufficient num- 

 ber of the old wells had been abandoned or required re- 

 placement. Water levels continued to decline gradually 

 until 1941, when the cone of depression was more than 25 

 feet below sea level under an extensive area, and locally as 

 much as 50 feet below sea level, and water levels were be- 

 low sea level under three-quarters of Brooklyn and several 

 square miles of neighboring Queens borough. The water 

 table rose gradually from 1941 to 1947 and at an accelerated 

 rate in succeeding years. 



Prior to 1917, all the public supplies for Brooklyn and 

 Queens came from ground water on Long Island, and the 

 draft reached an average 189 million gallons a day in 1916, 

 of which about half was pumped from wells within the two 

 boroughs. In 1917 these boroughs were connected to New 

 York City's Catskill supply. The ground-water pumpage 

 dropped to less than 50 million gallons a day in 1918, in- 

 creased again to more than 100 million gallons a day in 

 1931, and then trended gradually downward. Since 1947 

 there has been no pumping for public use in Brooklyn, and 

 industrial pumpage has been about 30 million gallons a day. 

 In Queens borough, pumpage in 1949 was about 60 million 

 gallons a day, of which about one-fourth was for industrial 

 use. 



Brooklyn's ground-water troubles have been aggravated 

 by its dearth of open spaces. About half of its 70 square miles 

 is covered by buildings and pavements, and the precipita- 



