A modeling study of water flow in the vadose zone beneath the Radioactive Waste Management Complex

Baca, R G; Magnuson, S O; Nguyen, H D; Martian, P

doi:10.2172/5593126

Cited by 8 publications

(21 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Hydrologic properties for the sedimentary lithologic units were derived primarily from site‐specific characterization and inverse modeling studies (McElroy and Hubbell, 1990; Baca et al, 1992; Bhorgese, 1988; Martian, 1995; Magnuson, 1995). Table 1 shows the assigned homogenous properties for the surficial sediment and the AB interbed.…”

Section: Base Model Developmentmentioning

confidence: 99%

See 1 more Smart Citation

Regulatory Modeling for the Idaho National Engineering and Environmental Laboratory's Subsurface Disposal Area and Conceptual Model Uncertainty Treatment

Magnuson

2004

Vadose Zone Journal

View full text Add to dashboard Cite

The Subsurface Disposal Area (SDA) at the Idaho National Engineering and Environmental Laboratory (INEEL) contains low‐level, hazardous, and transuranic wastes and is the subject of ongoing environmental assessments. The buried waste is in shallow land burial overlying a 180‐m‐thick vadose zone comprised of fractured basalts and sedimentary interbeds. Applied simulation studies to predict future contaminant concentrations from this buried waste have been conducted as part of ongoing regulatory‐driven environmental assessments for the SDA. An overview of the most recent numerical simulation study is presented along with a treatment of conceptual model uncertainty. The main premise of this paper is that conceptual uncertainty likely dominates parametric uncertainty, and this dominance should be considered when designing characterization studies. Given that the current modeling is uncalibrated due to inconsistent monitoring data in the vadose zone, it is only appropriate to consider conceptual model uncertainty. Conceptual model uncertainty was addressed by modeling different scenarios. Scenarios presented in this paper are the assignment of infiltration boundary conditions, a simplistic approximation to represent facilitated transport, and alternative representations of the moisture characteristic curve for fractured basalts. Results of this subsurface transport modeling have been used in part to guide additional field characterization activities. Eventually, predicted concentrations from this applied model will be used to estimate human health risks for a potential future receptor as part of the environmental assessment process.

show abstract

Section: Base Model Developmentmentioning

confidence: 99%

“…The parameters for the van Genuchten constitutive equations for all the sediments in the model were α = 1.066 m −1 , β = 1.523, and S wr = 0.142. These values were obtained from averaging the results of characterization activities on core samples from the surficial sediments (Baca et al, 1992).…”

Section: Base Model Developmentmentioning

confidence: 99%

Regulatory Modeling for the Idaho National Engineering and Environmental Laboratory's Subsurface Disposal Area and Conceptual Model Uncertainty Treatment

Magnuson

2004

Vadose Zone Journal

View full text Add to dashboard Cite

show abstract

“…A summary of several important modeling investigations is presented below. Baca et al (1992) used several analytical hydrological models to simulate infiltration rates, evaluate the effects of past flooding events on pit 10, and estimate water travel times in the vadose zone. Input parameters to the models included climatic data (specifically for the infiltration calculations), unsaturated hydraulic properties (including representative characteristic curves and hydraulic conductivity curves), and saturated hydraulic parameters such as hydraulic conductivity and effective porosity.…”

Section: 73mentioning

confidence: 99%

INEEL Subregional Conceptual Model Report; Volume 1 - Summary of Existing Knowledge of Natural and Anthropogenic Influences Governing Subsurface Contaminant Transport in the INEEL Subregion of the Eastern Snake River Plain

Wichlacz¹,

Orr²

2002

View full text Add to dashboard Cite

The National Research Council has defined a conceptual model as "an evolving hypothesis identifying the important features, processes, and events controlling fluid flow and contaminant transport of consequence at a specific field site in the context of a recognized problem." Presently, several subregional conceptual models are under development at the Idaho National Engineering and Environmental Laboratory (INEEL). Additionally, facility-specific conceptual models have been described as part of INEEL environmental restoration activities. Compilation of these models is required to develop a comprehensive conceptual model that can be used to strategically plan for future groundwater research activities at the INEEL.Conceptual models of groundwater flow and contaminant transport at the INEEL include the description of the geologic framework, matrix hydraulic properties, and inflows and outflows. They also include definitions of the contaminant source term and contaminant transport mechanisms.The geologic framework of the INEEL subregion is described by the geometry of the system, stratigraphic units within the system, and structural features that affect groundwater flow and contaminant transport. These elements define geohydrologic units that make up the Snake River Plain Aquifer (SRPA).The United States Geological Survey (USGS) conceptual model encompasses approximately 1,920 mi 2 of the eastern Snake River Plain. The Waste Area Group (WAG)-10 model includes the USGS area and additional areas to the northeast and southeast. Both conceptual models are bounded to the northwest by the Pioneer Mountains, Lost River Range, and Lemhi Mountains. They are bounded to the southeast by groundwater flow paths determined from aquifer water-level contours. The upgradient extent of the USGS model is a water-level contour that includes the northeastern boundary of the INEEL. The WAG-10 model includes more of the Mud Lake area to utilize previous estimates of underflow into the subregion. Both conceptual models extend approximately 25 miles to the southwest of the INEEL, a distance sufficient to include known concentrations of contaminant tracers.Several hypotheses have been developed concerning the effective thickness of the SRPA at the INEEL. The USGS model has defined the effective thickness from electrical resistivity and borehole data to be as much as 2,500 ft in the eastern part of the subregion and as much as 4,000 ft in the southwestern part. The WAG-10 model has developed two alternatives using aquifer-temperature and electricalresistivity data. The "thick" aquifer interpretation utilizes colder temperature data and includes a northtrending zone in which the thickness exceeds 1,300 ft and with a maximum thickness of 1,700 ft. The "thin" aquifer interpretation minimizes aquifer thickness, with thickness ranging from 328 to 1,300 ft. Facility-specific models generally have focused efforts on the upper 250 ft of saturation.Conceptual models have utilized a stratigraphic data set to define geohydrologic units within the INEEL...

show abstract

“…Specifically, the code has the ability to account for (a) liquid and vapor water movement, (b) heat transfer by conduction and convection, (c) evaporation at the soil surface, and (d) transpiration by plants. The UNSAT-H code was verified and benchmarked by Baca and Magnuson (1990) and was successfully applied to simulate moisture transport at several semi-arid locations (Fayer et al, 1992;Baca et al, 1992;Magnuson, 1993;Martian and Magnuson, 1993).…”

Section: Selected Modelmentioning

confidence: 99%

UNSAT-H infiltration model calibration at the Subsurface Disposal Area, Idaho National Engineering Laboratory

Martian¹

1995

Self Cite

View full text Add to dashboard Cite

A modeling study of water flow in the vadose zone beneath the Radioactive Waste Management Complex

Cited by 8 publications

References 5 publications

Regulatory Modeling for the Idaho National Engineering and Environmental Laboratory's Subsurface Disposal Area and Conceptual Model Uncertainty Treatment

Regulatory Modeling for the Idaho National Engineering and Environmental Laboratory's Subsurface Disposal Area and Conceptual Model Uncertainty Treatment

INEEL Subregional Conceptual Model Report; Volume 1 - Summary of Existing Knowledge of Natural and Anthropogenic Influences Governing Subsurface Contaminant Transport in the INEEL Subregion of the Eastern Snake River Plain

UNSAT-H infiltration model calibration at the Subsurface Disposal Area, Idaho National Engineering Laboratory

Contact Info

Product

Resources

About