Publications in Scientific Journals:

H.M. Wainwright, A. Flores-Orozco, M. Bücker, B. Dafflon, J. Chen, S. Hubbard, K. Williams:
"Hierarchical Bayesian method for mapping biogeochemical hot spots using induced polarization imaging";
Water Resources Research, 52 (2016), 533 - 551.

English abstract:
In floodplain environments, a naturally reduced zone (NRZ) is considered to be a common biogeochemical
hot spot, having distinct microbial and geochemical characteristics. Although important for
understanding their role in mediating floodplain biogeochemical processes, mapping the subsurface distribution
of NRZs over the dimensions of a floodplain is challenging, as conventional wellbore data are typically
spatially limited and the distribution of NRZs is heterogeneous. In this study, we present an innovative
methodology for the probabilistic mapping of NRZs within a three-dimensional (3-D) subsurface domain
using induced polarization imaging, which is a noninvasive geophysical technique. Measurements consist
of surface geophysical surveys and drilling-recovered sediments at the U.S. Department of Energy field site
near Rifle, CO (USA). Inversion of surface time domain-induced polarization (TDIP) data yielded 3-D images
of the complex electrical resistivity, in terms of magnitude and phase, which are associated with mineral
precipitation and other lithological properties. By extracting the TDIP data values colocated with wellbore
lithological logs, we found that the NRZs have a different distribution of resistivity and polarization from the
other aquifer sediments. To estimate the spatial distribution of NRZs, we developed a Bayesian hierarchical
model to integrate the geophysical and wellbore data. In addition, the resistivity images were used to estimate
hydrostratigraphic interfaces under the floodplain. Validation results showed that the integration of
electrical imaging and wellbore data using a Bayesian hierarchical model was capable of mapping spatially
heterogeneous interfaces and NRZ distributions thereby providing a minimally invasive means to parameterize
a hydrobiogeochemical model of the floodplain.

induced polarization, hydrogeology, natural attention

"Official" electronic version of the publication (accessed through its Digital Object Identifier - DOI)

Created from the Publication Database of the Vienna University of Technology.