Utilizing Pumping-Induced Reverse Water Level Fluctuations to Evaluate Fracture Connectivity in a Siliciclastic Aquifer System
Tuesday, September 24, 2013: 1:10 p.m.
Christopher Gellasch
,
Department of Preventive Medicine and Biometrics, Uniformed Services University of the Health Sciences, Bethesda, MD
Herb Wang
,
Department of Geoscience, University of Wisconsin-Madison, Madison, WI
Kenneth Bradbury
,
Wisconsin Geological & Natural History Survey, Madison, WI
Jean Bahr
,
Department of Geoscience, University of Wisconsin-Madison, Madison, WI
Reverse water-level fluctuations (RWFs), a phenomenon in which water levels rise briefly in response to pumping, were detected in monitoring wells in a fractured siliciclastic aquifer system near a deep public supply well. The magnitude and timing of RWFs provide important information that can help interpret aquifer hydraulics near pumping wells. A RWF in a well is normally attributed to poroelastic coupling between the solid and fluid components in an aquifer system. In addition to revealing classical pumping-induced poroelastic RWFs, data from pressure transducers located at varying depths and distances from the public supply well suggest that the RWFs propagate rapidly through fractures to influence wells hundreds of meters from the pumping well. The rate and cycling frequency of pumping is an important factor in the magnitude of RWFs. The pattern of RWF propagation can be used to better define fracture connectivity in an aquifer system. Rapid, cyclic head changes due to RWFs may also serve as a mechanism for contaminant transport.
Christopher Gellasch, Department of Preventive Medicine and Biometrics, Uniformed Services University of the Health Sciences, Bethesda, MD
Chris Gellasch is an Army Environmental Science and Engineering Officer and currently assigned as an assistant professor in the Department of Preventive Medicine and Biometrics at the Uniformed Services University of the Health Sciences in Bethesda, Maryland. He received his Ph.D. in Hydrogeology from the University of Wisconsin-Madison, his M.S. in Geology from Indiana University, and his B.S. in Geology from Eastern Michigan University. His current research combines aspects of hydrogeology and environmental engineering to determine the most likely pathways for sewer derived wastewater contaminants to migrate through the subsurface and impact public supply wells. combines aspects of hydrogeology and environmental engineering to determine the most likely pathways for sewer derived wastewater contaminants to migrate through the subsurface and impact public supply wells.
Herb Wang, Department of Geoscience, University of Wisconsin-Madison, Madison, WI
Herb Wang is a professor in the Department of Geoscience at the University of Wisconsin-Madison. He has a Ph.D. in Geophysics from the Massachusetts Institute of Technology, A.M. in physics from Harvard University, and a B.A. in physics from the University of Wisconsin. His current research is in deformation response to fluid injection in geothermal reservoirs and fiber-optic methods for monitoring rock mass behavior in underground facilities.
Kenneth Bradbury, Wisconsin Geological & Natural History Survey, Madison, WI
Ken Bradbury has been a research hydrogeologist/professor with the Wisconsin Geological and Natural History Survey, University of Wisconsin-Extension, in Madison, Wisconsin since 1982. He also serves as a coordinator of water and environmental programs for the Survey. He received his Ph.D. in Hydrogeology from the University of Wisconsin-Madison, his A.M. in Geology from Indiana University, and his B.A. in Geology from Ohio Wesleyan University.
Jean Bahr, Department of Geoscience, University of Wisconsin-Madison, Madison, WI
Jean Bahr is Professor of Hydrogeology in the Department of Geoscience at the University of Wisconsin-Madison, where she has been on the faculty since 1987. She received her Ph.D. and M.S. in Applied Earth Sciences (Hydrogeology) from Stanford University and her B.A. in Geology and Geophysics from Yale University. Her research explores physical, geochemical, and biogeochemical controls on the movement of water and associated solutes in subsurface geologic systems. She served as President of the Geological Society of America in 2009-2010 and is currently a member of the U.S. Nuclear Waste Technical Review Board.
