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[1] Cross-stratified deposits can give rise to a hierarchy of permeability modes, across scales, corresponding to a hierarchy of sedimentary unit types. The shape of the sample semivariogram for permeability can be largely controlled by the shape of the crosstransition probabilities of unit types having the greatest contrast in permeability. The shape of… (More)

- Caleb M Conrad, Robert W Ritzi, David F Dominic
- Ground water
- 2008

We considered small-scale measurement of permeability in pebbly sands having coarser grains supported in a finer grained matrix (fine packing). Our central question was whether air-based measurements are representative if made with a permeameter tip seal pressed in the sand matrix. We created pebbly sands and variably sorted sands, with systematic variation… (More)

[1] As analogs for aquifers, outcrops of sedimentary deposits allow sedimentary units to be mapped, permeability to be measured with high resolution, and sedimentary architecture to be related to the univariate and spatial bivariate statistics of permeability. Sedimentary deposits typically can be organized into hierarchies of unit types and associated… (More)

- Zhenxue Dai, Robert W. Ritzi, Chaocheng Huang, Yoram N. Rubin, David F. Dominic
- 2003

We consider here the Lagrangian approach for stochastic modeling of the transport of inert solutes in porous media. A general global covariance function of log conductivity in sediments with hierarchical organization has been developed by combining proportions, transition probabilities, and covariances of log conductivity. The global integral scale is… (More)

- James T Ferreira, Robert W Ritzi, David F Dominic
- Ground water
- 2010

Open-framework gravel has permeability, k, above the measurement range of most laboratory constant-head permeameters because the head difference across the length of conventional permeameters is too small to be measured. Here we addressed the challenge of measuring the high k by using a 3 m long permeameter. The head difference over this length was of the… (More)

- Patrick J Kamann, Robert W Ritzi, David F Dominic, Caleb M Conrad
- Ground water
- 2007

Porosity in sediments that contain a mix of coarser- and finer-grained components varies as a function of the porosity and volume fraction of each component. We considered sediment mixtures representing poorly sorted sands and gravely sands. We expanded an existing fractional-packing model for porosity to represent mixtures in which finer grains approach… (More)

- Christopher J Proce, Robert W Ritzi, David F Dominic, Zhenxue Dai
- Ground water
- 2004

A number of methods involving indicator geostatistics were combined in a methodology for characterizing and modeling multiscale heterogeneity. The methodology circumvents sources of bias common in data from borehole logs. We applied this methodology to the complex heterogeneity within a regional system of buried valley aquifers, which occurs in the western… (More)

- Lee B Porter, Robert W Ritzi, Lawrence J Mastera, David F Dominic, Behzad Ghanbarian-Alavijeh
- Ground water
- 2013

A procedure has been developed for calculating permeability (k) from the Kozeny-Carman equation, a procedure that links ideas from percolation theory with the ideas of Koltermann and Gorelick (1995) and Esselburn et al. (2011). The approach focuses on the proportion of coarser pores that are occupied by finer sediments relative to a percolation threshold… (More)

[1] We appreciate the commentary by Neuman [2006] and the opportunity for discussion and further clarification of our article [Ritzi et al., 2004]. In his commentary, Neuman expounds upon his derivation of a model for the permeability semivariogram [Neuman, 2003, equation (53)] and describes aquifer architecture that would be represented by such a model. As… (More)

We determined that the spatial heterogeneity in aquifer properties governing the reactive transport of volatile organic contaminants is defined by the arrangement of lithofacies. We measured permeability (k) and perchloroethene sorption distribution coefficient (Kd) for lithofacies that we delineated for samples from the Canadian Forces Base Borden Aquifer.… (More)