Individually owned shallow wells used for water supply and cess- 

 pools used for domestic waste disposal. 



Public supply wells that tap the deeper artesian hydrogeologic 

 units and use of cesspools for domestic waste disposal. 



Deep public supply wells and large scale communal sewage collec- 

 tion and disposal systems. 



It is the third stage of development that has a significant 

 impact. The effect of sewering and subsequent discharge to the ocean dis- 

 rupted the hydrologic balance resulting in large scale salt water encroach- 

 ment and lowered water levels in areas of large-scale pumping (the status of 

 water development in Long Island as of 1966 is shown on Fig. 13). 



j_ 



EXPLANATION 



SUBAREA CHARACTERISTICS 



A Hydrologic system mainly is in a state of virtual quantitative equilibrium. 

 B Transitional in development between subareas A and C. 

 C Hydrologic system is locally out of balance; local salt-water intrusion. 

 D Hydrologic system is out of balance: widespread salt-water intrusion. 



E Hydrologic system is out of balance; may be subject to salt-water intrusion in the future. 

 F Ground-water development is negligible, and the hydrologic system is in balance. 

 G Large parts of the subarea are contaminated with salty ground water owing to 

 former intensive ground-water development and related salt-water intrusion. 



Figure 13. Status of water development in 1966, 

 (1966, Fig. 8). 



After Heath and others 



31 



