Time-series monitoring in fractured-rock aquifers

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Time-lapse monitoring of subsurface processes is an emerging and promising area of hydrogeophysics. The combined use of non-invasive or minimally invasive geophysical methods with hydraulic and geochemical sampling is a cost-effective approach for aquifer characterization, long-term aquifer monitoring, and remediation monitoring. Time-lapse geophysical surveys can indirectly measure time-varying hydrologic parameters such as fluid saturation or solute concentration. Monitoring of time-varying hydrologic processes provides insight into aquifer properties and structure and aquifer responses to natural or induced stresses, such as seasonal fluctuations or fluid injection experiments for active remediation. The U.S. Geological Survey (USGS) Office of Ground Water, Branch of Geophysics, in cooperation with USGS Toxic Substances Hydrology Program, Environmental Protection Agency (USEPA), Department of Defense, the University of Connecticut, and Stanford University researchers, has applied time-lapse geophysics for site characterization and remediation monitoring in a number of studies. Recent and ongoing examples of time-lapse monitoring in fractured-rock aquifers include: 1) application of attenuation-difference, boreholeradar tomography used to monitor a series of sodium chloride tracer injection tests in fractured crystalline rock; 2) application of attenuation- and velocity-difference tomography and radar-reflection data to monitor steam injection in a fractured limestone aquifer; 3) design of an electrical resistivity tomography investigation to monitor the injection of resistive water into brackish water in a fractured limestone aquifer for aquifer storage and recovery (ASR); and 4) combined application of borehole-geophysical logging with long-term discreteinterval monitoring of hydraulic head and water-chemistry in a fractured crystalline-rock aquifer. These investigations demonstrate the application of geophysical methods to provide quantitative information about the subsurface critical for characterizing aquifer structure, flow dynamics, and hydraulic processes.

Study Area

Publication type Conference Paper
Publication Subtype Conference Paper
Title Time-series monitoring in fractured-rock aquifers
Year Published 2004
Language English
Publisher EPA/NGWA
Contributing office(s) Office of Ground Water, Toxic Substances Hydrology Program
Description 13 p.
Larger Work Type Book
Larger Work Subtype Conference publication
Larger Work Title Proceedings: 2004 U.S. EPA/NGWA fractured rock conference: State of the science and measuring success in remediation
First page 295
Last page 307
Conference Title 2004 U.S. EPA/NGWA Fractured Rock Conference: State of the Science and Measuring Success in Remediation
Conference Location Portland, ME
Conference Date September 13-15, 2004
Country United States
State New Hampshire
County Grafton County
Other Geospatial Mirror Lake, USGS Fractured-Rock Research site
Google Analytic Metrics Metrics page
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