BG Support for USGS District Hydrologists: Borehole-Geophysical Research at Aquifer Storage and Recovery Research Site in Charleston, South Carolina

Branch of Geophysics (BG) staff collaborated during Summer 2002 with the South Carolina District, providing support for borehole-geophysical surveys conducted using an electromagnetic-flowmeter tool. Matt Petkewich and Kevin Conlon of the South Carolina District, with support from John Williams (OGW BG), collected geophysical logs and conducted single- and cross-hole flowmeter tests at an Aquifer Storage and Recovery (ASR) research site in Charleston, South Carolina.

Prior to the trip, John Williams and the South Carolina District hydrologists discussed project needs and applicable borehole-geophysical methods. John spent two days in the field with the District hydrologists, training them in the use of the electromagnetic-flowmeter and acoustic-televiewer tools in the process of logging the first ASR observation well. The field work was followed by a day in the District office where the collected log data were processed and analyzed. A summary of the field results was sent to John Lane (OGW BG) in preparation for the next phase of the ASR work.

The logs and test results are being analyzed to help define the distribution and behavior of aquifer and confining units and to estimate the transmissivity, hydraulic head, and connectivity of permeable zones. The work was completed in preparation for the installation of an innovative electrical-resistivity imaging system by John Lane and Roelof Versteeg (Idaho National Engineering and Environmental Laboratory). The system will use a series of downhole electrodes placed against the borehole wall with a flexible borehole liner to continuously monitor the movement of fresh and brackish water in the aquifer during the ASR injection, storage, and withdrawal process.

This research was funded by the USGS Ground-Water Resources Program.

Matt Petkewich (USGS South Carolina) prepares the electromagnetic flowmeter used for the single- and cross-hole tests.

Matt Petkewich (USGS South Carolina) and Kevin Conlon (USGS South Carolina) lower a pump in the monitoring well for the single-hole flowmeter test.

Vertical borehole flow measured between major aquifer zones in the monitoring well in response to injection into the ASR well.