PROBLEMS FROM DEVELOPMENT 129 



better quality than the shallower aquifers, and it is the only 

 one yielding fresh water to wells on the barrier beach, for 

 the Boardwalk and communities on the open ocean. Wells 

 in this aquifer originally flowed by artesian pressure in At- 

 lantic City and at many other places along the coast. Pump- 

 ing has reduced the pressure more than 50 feet in extensive 

 areas and more than 100 feet in Atlantic City, so that water 

 levels in some wells are more than 75 feet below sea level. 

 The aquifer is protected from direct salt-water encroach- 

 ment from the ocean by overlying clays, but water un- 

 doubtedly moves into this deep cone of depression from the 

 part of the aquifer now under the ocean, and it is not known 

 to what extent that aquifer contains fresh water. 



During the Ice Age, when sea levels were several hundred 

 feet lower than today, fresh water may have moved through 

 the aquifer for some distance east of the present shore line. 

 The eastward extension of the aquifer, however, is evidently 

 not now open to the ocean, for, if it were, the 800-foot sand 

 at Atlantic City would probably already have a higher pro- 

 portion of salt. The present analysis of the situation at 

 Atlantic City is that the 800-foot sand, before pumping com- 

 menced, had water under sufficient artesian pressure to 

 move upward through the "confining" clays and discharge 

 at the land surface or into the ocean not very far away from 

 the present shore line. This natural discharge has been 

 eliminated in many places by lowering of the artesian pres- 

 sure below sea level, and the water instead is pumped from 

 wells. Thus there is a possibility of a substantial perennial 

 yield without salt-Avater contamination, even though the 

 artesian pressure is below sea level. Until there is indication 

 of increasing salinity in the easternmost wells, the draft may 

 be presumed to be within the limit of this perennial yield. 



Salt-water encroachment presents many problems in the 

 vicinity of Baltimore, Md. Although as a general rule cessa- 

 tion of pumping is a corrective to salt-water encroachment, 

 there are areas around Baltimore where it is advisable to con- 



