Recommended Basic Borehole Geophysics for Hydrologic Investigations in a Fractured Bedrock Aquifer

Monday, December 4, 2017: 11:50 a.m.
Rick A. Hoover, PG , Quality Geophysics, Quality Geosciences Company, LLC, Grantville, PA
Joseph T McNally , GeoServices Ltd, Camp Hill, PA

Hydrogeologists do not always receive a great exposure to borehole geophysics within many educational institutions, just as geophysicists do not get a lot of exposure to hydrogeology. Yet an often-heard inquiry from the hydrogeologist starts with “I have a 6-inch casing stick-up, but I don’t know much else about this well…” ending with “is there anything geophysics can do for me?” The geophysical choices can be many, and the answer sometimes depends on the person answering. Using a case history from a fouled groundwater supply well, constructed in the 1940’s, this presentation will look at a classic hydrologic suite of log measurements recommended to help the hydrogeologist understand the well and aquifer. In this particular instance, the well log was long lost to history, along with the well depth, yield, and water bearing zones and lithology. The geophysical investigation was designed to identify basic well characteristics to aid well rehabilitation. The basic logging suite recommended included Temperature, Caliper, Spontaneous Potential, Single Point Resistance, Normal Resistivity (8”, 16”, 32”, and 64”), Fluid Resistivity, Natural Gamma Radiation, Heat Pulse Flow Meter, and Optical Televiewer. None of the geophysical measurements is unusual. However, the combination provides well details and insight into geology and hydrogeology penetrated by this well. This recommended basic suite of borehole geophysical measurements should be included in all fundamental hydrogeologic investigations. The presentation will review the measured results for this well and compare the information to data gathered during the well rehabilitation process.
Rick A. Hoover, PG, Quality Geophysics, Quality Geosciences Company, LLC, Grantville, PA
Mr. Hoover has over 30-years of diverse background in near surface geophysical services applied to engineering, environmental, hydrogeologic and natural resource projects. Duties have included review of proposals and bid documents, equipment specifications, software testing and specifications, survey design, the development of standard geophysical operating procedures and project-specific quality management. Advancing the science, Mr. Hoover is a member of the American Society of Civil Engineers (ASCE), GeoInstitute geophysical subcommittee, Transportation Research Board geophysics subcommittee, and the ASTM committee 18.01 on Surface and Subsurface Characterization, and currently serves on the Board of Directors for the Environmental and Engineering Geophysical Society. Mr. Hoover was recipient of the 2015 Technical Achievement Award from the Harrisburg Section of ASCE.


Joseph T McNally, GeoServices Ltd, Camp Hill, PA
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