Geologic Data Package for 2001 Immobilized Low-Activity Waste Performance Assessment

Reidel, SP; Horton, DG

doi:10.2172/15170

Cited by 27 publications

(34 citation statements)

References 6 publications

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“…However, the materials penetrated below this depth generally consisted of stratified sand deposits, with variable silt content, and rare pebbles. This is consistent with the third layer (Layer 3) of a sandy sequence described by Reidel and Horton (1999) Figure 3. Grain size nomenclature (after Wentworth, 1922) and sediment classification scheme (modified after Folk, 1968) used at the Hanford Site…”

Section: Geologic Field Descriptionssupporting

confidence: 87%

Core Sampling in Support of the Vadose Zone Transport Field Study

Last¹,

Caldwell²

2001

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Section: Geologic Field Descriptionssupporting

confidence: 87%

Core Sampling in Support of the Vadose Zone Transport Field Study

Last¹,

Caldwell²

2001

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“…Flood sediments were deposited when ice dams in western Montana and northern Idaho were breached, and massive volumes of water spilled across eastern and central Washington. This process repeated itself numerous times prior to about 13,000 years, bringing to the Plateau a thick sequence of sediments known as the Hanford formation (Reidel and Horton 1999). The surface soil at the site is a coarse sand, locally known as a Quincy sand, which is associated with the Quincy soil series (mixed, mesic, Xeric Torripsamments).…”

Section: 2mentioning

confidence: 99%

Vadose Zone Transport Field Study: FY 2002 Status Report

Ward¹,

Gee²,

Zhang³

et al. 2003

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SummaryThe work reported in this paper is part of the U.S. Department of Energy's Science and Technology Initiative to develop improved conceptual models of flow and transport in the vadose zone, particularly for the Hanford Site, Washington. The National Academy of Sciences has identified significant knowledge gaps in conceptual model development as one reason for the discovery of subsurface contamination in unexpected places (NAS 2000). Inadequate conceptualization limits include, not only the understanding of long-term fate and transport, but also the selection and design of remediation technologies. Current conceptual models are limited, partly because they do not account for the random heterogeneity that contributes to the extremes of very nonlinear flow behavior typical of the Hanford vadose zone. A major improvement in the conceptual model of the Hanford vadose zone includes a better understanding and description of soil anisotropy, a property that appears to control much of the subsurface flow and transport in layered sediments at the Hanford Site.This project used a combination of geophysical and soil-physics techniques to investigate the infiltration and redistribution of water and dilute tracers in a controlled field experiment at the Army loop Road clastic dike study area at the Hanford Site, near Richland, Washington. In the FY 2002 tests, surfacedeployed ground-penetrating radar was used to identify the discrete pattern of horizontal layering that comprises the coarse component of the heterogeneity along a 60-m transect. The transect was instrumented to allow water to be applied along its length from a line source. Local-scale water content, matric potential, and tracer concentrations were monitored as a function of spatial scale by multipurpose time-domain reflectometry probes and suction lysimeters (solution samplers). The resulting data were used to characterize fine-scale heterogeneity as well as correlation lengths of hydraulic and transport parameters. Tracer breakthrough data were used to determine longitudinal and transverse dispersivit ies and their scale dependence. Parameters were analyzed to identify a suitable averaging (upscaling) procedure for field-scale infiltration predictions. Distributions of water and solute were found to be spatially dependent and controlled by the fine-scale features present both at the clastic dike and near the horizontal sill that was found to emanate from the dike. A theory of anisotropy was developed and successfully tested based on observations at the clastic dike site. The results of this study will help to bridge the gap between local-scale transport observations and field-scale transport behavior. It will allow the validation of recently developed inverse procedures for predicting field-scale parameters and will improve our prediction capability for heterogeneous sediments at Hanford. The improved conceptualizations will permit DOE to make defensible corrective and remedial-action decisions at the Hanford Site.

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“…The materials penetrated below this depth generally consisted of stratified sand deposits, with variable silt content and rare pebbles. Last and Caldwell (2001) reported that these materials were consistent with the third layer (Layer 3) of a sandy sequence described by Reidel and Horton (1999) within the uppermost Hanford formation beneath the southeast portion of 200 East Area. The latest ILAW borehole 299-E24-21 confirmed the presence of a thick bedded sand sequence from near the surface to ~91.5 m (300 ft) depth.…”

Section: Geologic Descriptionsmentioning

confidence: 62%

Sampling of Borehole WL-3A through -12 in Support of the Vadose Zone Transport Field Study

Caldwell¹,

Owen²

2001

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SummaryThis report presents the results of the fiscal year (FY) 2001 core sampling effort conducted to support the Vadose Zone Transport Field Study (VZTFS). The VZTFS has been conducting a series of controlled near-surface tracer tests at the 299-E24-111 Experiment Test-Well Site (also known as the Sisson and Lu site). The purpose of these tests is to address principal uncertainties affecting the understanding of current contaminant distributions under Hanford waste sites, and to improve the prediction of future migration through the vadose zone (Ward and Gee 2000). The FY 2001 tests were conducted using a concentrated sodium thiosulfate tracer (Ward and Gee 2001). Subsurface monitoring of the tracer test was conducted using various geophysical and geochemical methods.This report presents the results from ten soil borings installed before, during, and after the tracer was injected. The first two soil borings were sampled seven days prior to the initiation of the tracer injections. Two more soil borings were sampled midway during the series of injections, and the remaining six soil borings were installed at three different times after the cessation of the injections. Over 300 soil samples were collected using a cone penetrometer and wireline sampling tools. The samples generally ranged in depth from 4.6 to 17.4 m (15 to 57 ft). Selected samples were analyzed for percent fines, moisture content, and/or tracer concentrations.Preliminary results from the core sample analyses indicate that the major concentration front of the thiosulfate tracer reached a relative depth of at least 5.5 m (18 ft) below the injection point 17 days after the tracer injections began. Fifty-one days later the tracer appears to have migrated to a relative depth of at least 12.3 m (40.5 ft). Lateral spreading appears to have exceeded 5.8 m (19 ft) even at these deepest points of migration. These data will be used in combination with other geophysical and geochemical results to further our understanding of contaminant transport within the vadose zone.v

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Geologic Data Package for 2001 Immobilized Low-Activity Waste Performance Assessment

Cited by 27 publications

References 6 publications

Core Sampling in Support of the Vadose Zone Transport Field Study

Core Sampling in Support of the Vadose Zone Transport Field Study

Vadose Zone Transport Field Study: FY 2002 Status Report

Sampling of Borehole WL-3A through -12 in Support of the Vadose Zone Transport Field Study

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