Electrical characterization of non‐Fickian transport in groundwater and hyporheic systems

Abstract

[1] Recent work indicates that processes controlling solute mass transfer between mobile and less mobile domains in porous media may be quantified by combining electrical geophysical methods and electrically conductive tracers. Whereas direct geochemical measurements of solute preferentially sample the mobile domain, electrical geophysical methods are sensitive to changes in bulk electrical conductivity (bulk EC) and therefore sample EC in both the mobile and immobile domains. Consequently, the conductivity difference between direct geochemical samples and remotely sensed electrical geophysical measurements may provide an indication of mass transfer rates and mobile and immobile porosities in situ. Here we present (1) an overview of a theoretical framework for determining parameters controlling mass transfer with electrical resistivity in situ; (2) a review of a case study estimating mass transfer processes in a pilot-scale aquifer storage recovery test; and (3) an example application of this method for estimating mass transfer in watershed settings between streams and the hyporheic corridor. We demonstrate that numerical simulations of electrical resistivity studies of the stream/hyporheic boundary can help constrain volumes and rates of mobile-immobile mass transfer. We conclude with directions for future research applying electrical geophysics to understand field-scale transport in aquifer and fluvial systems subject to rate-limited mass transfer.

Investigating the impact of advective and diffusive controls in solute transport on geoelectrical data

“…This observation indicates that electrical geophysical data, in conjunction with saline tracer tests, may provide evidence about scales of mass transfer in controlling solute breakthrough behavior. This conclusion was further supported by theoretical work in Day-Lewis and and Singha et al (2008).…”

How Does Subsurface Characterization Affect Simulations of Hyporheic Exchange?

“…Although not hyporheic in application, several studies suggest ER imaging of solute tracers could be an informative technique to characterize hydrologic process dynamics. Indeed, saline tracers have recently been used to characterize hyporheic exchange in both field (Nyquist et al 2008;Ward et al 2010b) and numerical studies (Singha et al 2008;Ward et al 2010a). ER imaging of saline tracers has been used to inform groundwater flow properties (e.g., White 1988;Bevc and Morrison 1991) including preferential flowpaths (e.g., Schima et al 1996), and have been used to parameterize numerical models of flow and transport in the subsurface (Binley et al 1996b;Kemna et al 2002).…”

A field comparison of multiple techniques to quantify groundwater–surface-water interactions

“…Large-scale observations, such as remote sensing applied to stream geomorphology, may miss dominant local-scale features (Legleiter et al 2004, Adams and Spotila 2005, Wörman et al 2007). This issue is even more critical in evaluation of subsurface properties, despite advances in hydrogeophysical exploration techniques (Kemna et al 2002, Singha et al 2008, Ward et al 2010. Stream-tracer techniques yield integrated information about a stream and its transient-storage zones (surface and subsurface), but flow paths with greater residence times than the time scale of the experiment cannot be detected (e.g., Harvey and Wagner 2000, Ward et al 2013a, Schmadel et al 2013.…”