Predictive modeling of flow and transport in a two‐dimensional intermediate‐scale, heterogeneous porous medium

Abstract

Abstract. As a first step toward understanding the role of sedimentary structures in flow and transport through porous media, this work deterministically examines how small-scale laboratory-measured values of hydraulic conductivity relate to in situ values of simple, artificial structures in an intermediate-scale (10 rn long), two-dimensional, heterogeneous, laboratory experiment. Results were judged based on how well simulations using measured values of hydraulic conductivities matched measured hydraulic heads, net flow, and transport through the tank. Discrepancies were investigated using sensitivity analysis and nonlinear regression estimates of the in situ hydraulic conductivity that produce the best fit to measured hydraulic heads and net flow. Permeameter and column experiments produced laboratory measurements of hydraulic conductivity for each of the sands used in the intermediate-scale experiments. Despite explicit numerical representation of the heterogeneity the laboratory-measured values underestimated net flow by 12-14% and were distinctly smaller than the regression-estimated values. The significance of differences in measured hydraulic conductivity values was investigated by comparing variability of transport predictions using the different measurement methods to that produced by different realizations of the heterogeneous distribution. Results indicate that the variations in measured hydraulic conductivity were more important to transport than variations between realizations of the heterogeneous distribution of hydraulic conductivity. IntroductionThe heterogeneity of natural systems confounds attempts to achieve accurate groundwater flow and transport models. 2U.S. Geological Survey

On the importance of diffusion and compound-specific mixing for groundwater transport: An investigation from pore to field scale

“…Intermediate-scale flow-through chambers are increasingly used to study key processes affecting solute transport such as the impact of heterogeneity on conservative transport (e.g., Barth et al, 2001;Levy and Berkowitz, 2003;McNeil et al, 2006;Silliman et al, 1998), mixing in the longitudinal (e.g., Gramling et al, 2002) and transverse direction (e.g., Haberer et al, 2011Haberer et al, , 2012Rolle et al, 2009); abiotic reactions (e.g., Katz et al, 2011;Loyaux-Lawniczak et al, 2012) and biodegradation (e.g., Bauer et al, 2009aBauer et al, , 2009bHuang et al, 2003;Rolle et al, 2010;Thullner et al, 2002). In this work we refer to the study presented by Bauer et al (2009b) and, in particular, to the data collected during an initial phase of conservative transport and during a selected phase of aerobic bioreactive transport.…”

HydrogeoSieveXL: an Excel-based tool to estimate hydraulic conductivity from grain-size analysis

“…At the same time, it must be conceded that after more than a century of trying, the goal of obtaining a value of K in the laboratory that is fully representative of K in an aquifer has yet to be achieved (Rosas et al 2014). The reasons for this include factors such as geologic heterogeneity (particularly as it affects aquifer structure, which is disrupted in the grain-size-analysis procedures), the nature of porosity, subtle effects related to grain shapes and packing (Dullien 1991), and in some cases variations in porewater pressure (Barth et al 2001).…”

Highlighting the implications of selenium dispersion from disposal of Kahota Industrial Triangle area, Islamabad, Pakistan using three-dimension solute transport model

“…Review of the literature indicates that modeling of different kinds of contaminant has been studied by several researchers. Among them most prominent includes Wilber (1980), Copoulos and Sehayek (1986), Hutson and Wagenet (1989), Shifang (1991), Hooshmand (1992), Zheng and Bennett (1997), Feehley et al (2000), Holder et al (2000), Barth et al (2001), Boutt et al (2001), Elci et al (2001, Mehl and Hill (2001), Julian et al (2001), Shamrukh et al (2001), Faidi et al (2002), Zheng and Wang (2002), Andrews and Neville (2003), Bakker (2003), Brown and Glynn (2003), Conan et al (2003), Harrar et al (2003), Langevin (2003), Prommer et al (2003), Zheng and Gorelick (2003), Liu et al (2004), and Wang and Bright (2004). Risk assessments of the subsurface environment often involve the use of quantitative contaminant fate and transport models.…”