Documenting Hydrogeologic Information Obtained from Deep-Borehole Drilling in Suffolk County, New York

 

 

Borehole drilling and  well-installation are costly procedures,  and securing funding for new well  installation for the sake of research is  often difficult.The Suffolk County Water  Authority (SCWA) maintains a  large network of deep wells for public  supply that is constantly being upgraded  as water demands increase. During the  drilling process, contractors record  drillers’ logs and collect cores and,  subsequently, often perform borehole  geophysical logging for determination  of aquifer properties. However,  although these data may suffice for selecting a screen zone, they are lacking in more detailed hydrologic information necessary for a better understanding of Suffolk County’s hydrologic system. A comprehensive database documenting pertinent hydrologic information obtained from borehole drilling is needed.  The main objective will be to coordinate data-collection activities with the SCWA’s drilling operations for the purpose of collecting, analyzing, updating, and archiving hydrogeologic information. The database information will help understand and characterize the hydrogeology of aquifer systems throughout the County. This information will be used to determine altitudes of major hydrologic units penetrated by wells located throughout the County, and to facilitate developing and updating maps and sections of sub-surface hydrogeology. These objectives are to be met by the following:
 

1. having a hydrologist at select test- and production wells during drilling and(or) coring for up to one week at eight sites annually to maintain a geologist’s log;
2. collecting, describing, and archiving sediment cores and sieve samples at specified intervals and (or) facies changes; 
3. importing drillers’ and (or) geologists’ logs and geophysical logs in paper format into a geographic information system (GIS) for archival;
4. archiving other hydrogeologic data (for example, core photographs) in an electronic database;
5. digitally capturing a few (2–3) critical legacy geophysical paper logs annually with a large-format digitizing tablet and archiving the resulting electronic logs in the borehole database, and;
6. supplying new data that facilitates developing and updating hydrogeologic maps and sections