A Demonstration of the System Assessment Capability (SAC) Rev. 1 Software for the Hanford Remediation Assessment Project

Eslinger, Paul W.; Kincaid, C.T.; Nichols, William; Wurstner, S.K.

doi:10.2172/896078

Cited by 7 publications

(13 citation statements)

References 33 publications

(37 reference statements)

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“…Previously, Fayer et al (2010) summarized the major data collection and modeling efforts that are available for Hanford Site-wide evaluation of contamination and need for remediation. In addition, Eslinger et al (2006) developed a suite of interrelated computer codes, termed the System Assessment Capability (SAC), and used the SAC to conduct a series of risk analyses for nearly all of the Central Plateau waste sites (410 sites were included).…”

Section: Potential Applications and Case Study Examplesmentioning

confidence: 99%

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Remedy Evaluation Framework for Inorganic, Non-Volatile Contaminants in the Vadose Zone

Truex¹,

Carroll²

2013

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Contaminants in the vadose zone may be a long-term source of groundwater contamination and need to be considered in remedy evaluations. In many cases, remediation decisions for the vadose zone will need to be made all or in part based on projected impacts to groundwater. There are significant natural attenuation processes inherent in vadose zone contaminant transport. Attenuation processes include both hydrobiogeochemical processes that serve to retain contaminants within porous media and physical processes that slow the vertical rate of movement for disposed water and waste solutions. In particular, the physical processes controlling fluid flow in the vadose zone are quite different and generally have a more significant attenuation impact on contaminant transport relative to those within the groundwater system. A remedy evaluation framework is presented herein that uses an adaptation of the established EPA Monitored Natural Attenuation evaluation approach integrated into an approach based on a conceptual model focused on identifying and quantifying features and processes that control contaminant flux through the vadose zone. This report presents a framework to support evaluation of contaminant fate and transport in the vadose zone and bridges this analysis to refinement of the site conceptual model, assessment of risk, and support for baseline risk assessment and remedy selection.v

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Section: Potential Applications and Case Study Examplesmentioning

confidence: 99%

“…The SAC results (Eslinger et al 2006) were used as the root data for the categorization in Table 2. The predicted impact to groundwater at each of the 410 waste sites was evaluated based on the maximum concentration in groundwater divided by the drinking water standard (DWS), which was termed DWS Factor.…”

Section: Potential Applications and Case Study Examplesmentioning

confidence: 99%

Remedy Evaluation Framework for Inorganic, Non-Volatile Contaminants in the Vadose Zone

Truex¹,

Carroll²

2013

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“…DOE-RL (2008) examined the available information on potential deep vadose zone contamination of technetium and uranium in partial fulfillment of Tri-Party Agreement (TPA) Milestone M-015-50, Submit a Treatability Test Work Plan for Deep Vadose Zone Technetium and Uranium to Ecology and EPA (Ecology et al 1989). The available information included disposal inventories, depth of contamination, and potential risk to groundwater (Eslinger et al 2006). Although the information sources have large uncertainties, DOE-RL (2008) was able to identify specific sites that potentially contained significant quantities of technetium-99 and uranium in the deep vadose zone such that they merit consideration for some form of remediation to protect groundwater.…”

Section: Problem Definitionmentioning

confidence: 99%

Technical Basis for Evaluating Surface Barriers to Protect Groundwater From Deep Vadose Zone Contamination

Jm¹,

Vl²,

Al³

et al. 2010

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The U.S. Department of Energy (DOE) and its predecessors released nearly 2 trillion liters (450 billion gallons) of contaminated liquid into the vadose zone at the Hanford Site. Some of the contaminants currently reside in the deeper parts of the vadose zone where they are much less accessible to characterization, monitoring, and typical remediation activities such as removal and disposal. The DOE Richland Operations Office (DOE-RL) prepared a treatability test plan in 2008 to examine remediation options for addressing contaminants in the deep vadose zone; one of the technologies identified was surface barriers (also known as engineered barriers, covers, and caps).Surface barriers have long been used to isolate contaminants from the accessible environment. In the typical configuration, the contaminants are located relatively close to the surface, generally within 15 m, and thus they are close to the base of the surface barrier. The proximity of the surface barrier under these conditions yielded few concerns about the effectiveness of the barrier at depth, particularly for cases in which the contaminants were in a lined facility. At Hanford, however, some unlined sites have contaminants located well below depths of 15 m, which means that the contaminants are increasingly distant from the surface barrier meant to isolate them from the accessible environment. The issue raised about these sites is the degree of effectiveness of a surface barrier in isolating contaminants in the deep vadose zone. Previous studies by Hanford Site and PNNL researchers suggest that surface barriers have the potential to provide a significant degree of isolation of deep vadose zone contaminants. The studies show that the actual degree of isolation is site-specific and depends on many factors, including recharge rates, barrier size, depth of contaminants, geohydrologic properties of the sediments, and the geochemical interactions between the contaminants and the sediments.After the DOE-RL treatability test plan was published, Pacific Northwest National Laboratory was contracted to review the information available to support surface barrier evaluation for the deep vadose zone, identify gaps in the information and outcomes necessary to fill the data gaps, and outline tasks to achieve those outcomes. Full understanding of contaminant behavior in the deep vadose zone is constrained by four key data gaps: limited access; limited data; limited time; and the lack of an accepted predictive capability for determining whether surface barriers can effectively isolate deep vadose zone contaminants. Activities designed to fill these data gaps need to have these outcomes:• common evaluation methodology that provides a clear, consistent, and defensible basis for evaluating groundwater impacts caused by placement of a surface barrier above deep vadose zone contamination• deep vadose zone data that characterize the lithology, the spatial distribution of moisture and contaminants, the physical, chemical, and biological process that affect the mobility of ea...

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“…The SGM updated an earlier model ) by using current geologic interpretations and extending the original hydraulic head observation data set (1944 through 1996) through the year 2004. Water fluxes for these facilities from the vadose zone to the unconfined aquifer used in this updated SGM calibration effort were developed with the vadose zone module of the System Assessment Capability (SAC) (Eslinger et al 2006). In addition to new estimates of hydraulic conductivities and areal recharge, new estimates of boundary fluxes were obtained for Dry Creek and Cold Creek Valleys.…”

Section: 4mentioning

confidence: 99%

“…The transient calibration also included the discharge of large volumes of waste water to a variety of waste facilities. The vadose zone module of the SAC was used to provide these water and contaminant flux estimates to the groundwater (Eslinger et al 2006). In addition to new estimates of hydraulic conductivities and areal recharge, new estimates of boundary fluxes, including Cold Creek and Dry Creek Valleys (Figure 2.3), were also revised.…”

Section: Site-wide Groundwater Model (Sgm)mentioning

confidence: 99%

Potential Impacts of Leakage from Black Rock Reservoir on the Hanford Site Unconfined Aquifer: Initial Hypothetical Simulations of Flow and Contaminant Transport

Freedman¹

2007

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A Demonstration of the System Assessment Capability (SAC) Rev. 1 Software for the Hanford Remediation Assessment Project

Cited by 7 publications

References 33 publications

Remedy Evaluation Framework for Inorganic, Non-Volatile Contaminants in the Vadose Zone

Remedy Evaluation Framework for Inorganic, Non-Volatile Contaminants in the Vadose Zone

Technical Basis for Evaluating Surface Barriers to Protect Groundwater From Deep Vadose Zone Contamination

Potential Impacts of Leakage from Black Rock Reservoir on the Hanford Site Unconfined Aquifer: Initial Hypothetical Simulations of Flow and Contaminant Transport

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