Variability and scaling of hydraulic properties for 200 Area soils, Hanford Site

Khaleel, Raziuddin; Freeman, Eugene

doi:10.2172/188564

Cited by 74 publications

(130 citation statements)

References 9 publications

Supporting

Mentioning

126

Contrasting

Order By: Relevance

“…Among the PSD measurements, 60 are from boreholes S-1, S-2, and S-3 [Schaap et al, 2003], 17 from A-7, E-1, and E-7 [Khaleel and Freeman, 1995], and 16 from E-1, E-7, and B-8 [Fayer et al, 1993]. Locations of the boreholes are shown in Figure 1.…”

Section: Soil Textural Classes and Initial Moisture Contentsmentioning

confidence: 99%

A Markov chain model for characterizing medium heterogeneity and sediment layering structure

Khaleel

2008

Water Resources Research

View full text Add to dashboard Cite

[1] By leveraging use of ''soft'' data (e.g., initial moisture content, q i ), this study applies the transition probability (TP) based Markov chain (MC) model to sediment textural classes for characterizing the medium heterogeneity and sediment layering structure. The TP/MC method is evaluated by simulating the vadose zone moisture movement at a field site, where the stratigraphy consists of imperfectly stratified soil layers. Soil heterogeneity is characterized via spatial variability of the geometry of soil textural classes. When the q i measurements, which carry signature about medium heterogeneity and stratigraphy, are not included in the TP/MC model, it is not possible to identify the horizontal TP. The q i measurements, when transformed into soil classes, are necessary in mapping the soil layering structure prevalent at the site. The soil hydraulic parameters for each soil class are treated deterministically and are estimated on the basis of core samples. To evaluate uncertainty in characterizing geometry of the soil classes, multiple conditional realizations of the soil classes are generated. A Monte Carlo simulation shows that the simulated mean moisture contents agree well with corresponding field observations. The observed splitting of the moisture plume in a coarse sand layer that is sandwiched between two fine-textured layers, the southeastward movement of the plume during the redistribution period, and the near-zero fluid flux below the bottom fine layer are adequately simulated. Spatial variability of the field-measured moisture content is sufficiently captured by the 95% confidence intervals calculated from the Monte Carlo simulations. Investigating the effect of data conditioning on the simulated results shows that a reduction of conditioning data does not necessarily deteriorate simulation results if other conditioning data exist within the mean length of the soil classes. The TP/MC method is flexible so that other types of site characterization data (e.g., geophysical data) can be incorporated as they become available.Citation: Ye, M., and R. Khaleel (2008), A Markov chain model for characterizing medium heterogeneity and sediment layering structure, Water Resour. Res., 44, W09427,

show abstract

Section: Soil Textural Classes and Initial Moisture Contentsmentioning

confidence: 99%

A Markov chain model for characterizing medium heterogeneity and sediment layering structure

Khaleel

2008

Water Resources Research

View full text Add to dashboard Cite

show abstract

“…Retention parameters, porosities, and hydraulic conductivities were obtained from Khaleel et al 2001 andFreeman (1995). The published van Genuchten (1980) saturation-pressure parameters were converted to equivalent Brooks-Corey (1964) parameters using the algorithms presented by Lenhard et al (1989).…”

Section: Hydraulic Propertiesmentioning

confidence: 99%

Carbon Tetrachloride Flow and Transport in the Subsurface of the 216-Z-18 Crib and 216-Z-1A Tile Field at the Hanford Site: Multifluid Flow Simulations and Conceptual Model Update

Oostrom¹,

Rockhold²,

Thorne³

et al. 2006

View full text Add to dashboard Cite

Three-dimensional modeling was conducted with layered models to further develop the conceptual model of CT distribution in the vertical and lateral direction beneath the 216-Z-1A tile field and 216-Z-18 cribs and to investigate the effects of soil vapor extraction (SVE). Base case and sensitivity analysis simulations considered migration of dense, nonaqueous phase liquid (DNAPL) consisting of CT and co-disposed organics in the subsurface beneath the two disposal sites as a function of the properties and distribution of subsurface sediments and of the properties and disposal history of the waste. Simulations of CT migration were conducted using the Subsurface Transport Over Multiple Phases (STOMP) simulator.Simulation results support a conceptual model for CT distribution where CT in the DNAPL phase is expected to have migrated primarily in a vertical direction below the disposal trench. None of the simulations predicted that CT in the DNAPL phase would move across the water table below the 216-Z-18 site. Movement of CT in the DNAPL phase across the water table below the 216-Z-1A site was only predicted in simulations with smaller disposal areas and larger volumes, compared to the base case simulation, and in isotropic porous media. Because uncertainties in disposal area and volume exist, movement of CT in the DNAPL phase across the water table in the subsurface below the 216-Z-1A site should be considered as a possibility. However, even if DNAPL moved across the water table in the past, there may not currently be a DNAPL phase in the groundwater beneath the 216-Z-1A site because of dissolution. Results also show that the Hanford 1a geologic unit, located just beneath the 216-Z-1A and 216-Z18 disposal areas, retains more CT DNAPL within the vadose zone during infiltration and redistribution than other hydrologic units. During simulated SVE operations, CT in this unit remained in the subsurface while DNAPL in other layers was effectively removed. Additional characterization of the Hanford 1a unit below the two disposal sites would provide valuable information about the quantity of DNAPL phase CT remaining in the vadose zone. A significant amount of the disposed CT DNAPL may have partitioned to the vapor phase and subsequently into water and sorbed phases. As for the 216-Z-9 site, it is predicted that any continued migration of CT from the vadose zone to the groundwater is likely to occur through interaction of vapor phase CT with the groundwater and not through continued DNAPL migration. The results indicated that SVE appears to be an effective technology for vadose zone remediation, but additional effort is needed to improve simulation of the SVE process through an enhanced understanding of rate-limited volatilization. A total of 34 three-dimensional simulations have been conducted based on a layered EarthVision™ geologic model, which is an interpretation of available geologic data. These simulations consist of one base case simulation and 33 sensitivity analysis simulations. These simulations examined the infilt...

show abstract

“…Parameters for the van Genuchten and Mualem models have been determined by fitting experimental data for Hanford Site sediments to the classic analytic expressions of these models. These results are described in several Hanford Site documents; however, the parameters used in the initial iteration of the Composite Analysis were compiled by Khaleel and Freeman (1995).…”

Section: Release Modelmentioning

confidence: 99%

“…The impact of larger particles was corrected using Gravel %. Data are from Khaleel and Freeman (1995). A normal distribution was assumed for the parameters van Genuchten n, residual, and saturated water content, and the mean was calculated accordingly.…”

Section: Release Modelmentioning

confidence: 99%

Addendum to Composite Analysis for Low-Level Waste Disposal in the 200 Area Plateau of the Hanford Site

Bergeron¹,

Freeman²,

Wurstner³

et al. 2001

View full text Add to dashboard Cite

Variability and scaling of hydraulic properties for 200 Area soils, Hanford Site

Cited by 74 publications

References 9 publications

A Markov chain model for characterizing medium heterogeneity and sediment layering structure

A Markov chain model for characterizing medium heterogeneity and sediment layering structure

Carbon Tetrachloride Flow and Transport in the Subsurface of the 216-Z-18 Crib and 216-Z-1A Tile Field at the Hanford Site: Multifluid Flow Simulations and Conceptual Model Update

Addendum to Composite Analysis for Low-Level Waste Disposal in the 200 Area Plateau of the Hanford Site

Contact Info

Product

Resources

About