On the mechanism of the large hydraulic gradient under Yucca Mountain, Nevada

Fridrich, Christopher J.; Ge, Shemin; Sass, J.H.

doi:10.3133/ofr98119

Cited by 2 publications

(2 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, just to the north of Yucca Mountain, the water table steeply dips, with a drop of almost 300 m in depth over a very short distance. The region termed the Large Hydraulic Gradient region [33], or LHG, has been the subject of considerable study and modeling [32,34]. In its early years, it was suggested that it was a perched water table [35] while now it appears to be considered part of the regional aquifer system.…”

Section: The Underground Waterfallmentioning

confidence: 99%

“…However, the fact that the anomalous groundwater behavior immediately to the north of the proposed repository is not understood nor has any evidence to support a solid conceptual model adds a significant amount of uncertainty to the general understanding of the groundwater beneath Yucca Mountain. In the early years of Yucca Mountain, the National Academy of Sciences, in reviewing the site conclude: "not until the source of the gradient (the >300 m water table decline) is known can the potential hazard that the repository may face due to climate changes and/or tectonic events be evaluated with a high level of confidence" [33,36]. Its impact on the transport characteristics from Yucca Mountain may not be greatly significant, but it seems critical that major uncertainties, such as what makes the groundwater drop~300 m in 2 km, be explainable and backed by field data.…”

Section: The Underground Waterfallmentioning

confidence: 99%

See 1 more Smart Citation

Are Arid Regions Always that Appropriate for Waste Disposal? Examples of Complexity from Yucca Mountain, Nevada

Tyler

2020

Geosciences

View full text Add to dashboard Cite

The study of the hydrology of arid regions greatly expanded at the end of the 20th century as humans sought to reduce groundwater pollution from landfills, waste dumps and other forms of land disposal. Historically viewed as wastelands where little or no water percolated to the underlying water table, the discovery of large-scale contamination beneath arid disposal sites such as the Hanford nuclear complex in eastern Washington jumpstarted an industry in studying the hydrology of arid vadose zones and their transport behavior. These studies showed that, in spite of hyper aridity in many areas, precipitation often did infiltrate to deep water. The efforts at Yucca Mountain, Nevada to design a high-level nuclear repository stand out as one of the largest of such studies, and one that fundamentally changed our understanding of not only water flow in fractured rocks, but also of the range of our uncertainty of hydrologic processes in arid regions. In this review and commentary, we present some of the initial concepts of flow at Yucca Mountain, and the evolution in research to quantify the concepts. In light of continued stockpiling of high-level waste, and the renewed interest in opening Yucca Mountain for high-level waste, we then focus on the significant surprises and unanswered questions that remained after the end of the characterization and licensing period; questions that continue to demonstrate the challenges of a geologic repository and our uncertainty about critical processes for long-term, safe storage or disposal of some of our most toxic waste products.

show abstract

Section: The Underground Waterfallmentioning

confidence: 99%

Section: The Underground Waterfallmentioning

confidence: 99%

Are Arid Regions Always that Appropriate for Waste Disposal? Examples of Complexity from Yucca Mountain, Nevada

Tyler

2020

Geosciences

View full text Add to dashboard Cite

show abstract

Groundwater flow systems at the Nevada Test Site, Nevada: A synthesis of potentiometric contours, hydrostratigraphy, and geologic structures

Fenelon¹,

Sweetkind²,

Laczniak³

2010

Professional Paper

View full text Add to dashboard Cite

Contaminants introduced into the subsurface of the Nevada Test Site by underground nuclear testing are of concern to the U.S. Department of Energy and regulators responsible for protecting human health and safety. The potential for contaminant movement away from the underground test areas and into the accessible environment is greatest by groundwater transport. The primary hydrologic control on this transport is evaluated and examined through a series of contour maps developed to represent the hydraulichead distribution within each of the major aquifers underlying the area. Aquifers were identified and their extents delineated by merging and analyzing multiple hydrostratigraphic framework models developed by other investigators from existing geologic information. A map of the hydraulic-head distribution in each major aquifer was developed from a detailed evaluation and assessment of available water-level measurements. Multiple spreadsheets that accompany this report provide pertinent water-level and geologic data by well or drill hole. Aquifers are mapped and discussed in general terms as being one of two types: alluvial-volcanic, or carbonate. Both aquifer types are subdivided and mapped as independent regional and local aquifers, based on the continuity of their component rock. Groundwater-flow directions, approximated from potentiometric contours that were developed from the hydraulic-head distribution, are indicated on the maps and discussed for each of the regional aquifers and for selected local aquifers. Hydraulic heads vary across the study area and are interpreted to range in altitude from greater than 5,000 feet in a regional alluvial-volcanic aquifer beneath a recharge area in the northern part of the study area to less than 2,300 feet in regional alluvial-volcanic and carbonate aquifers in the southwestern part of the study area. Flow directions Purpose and Scope The purpose of this report is to delineate the major aquifers beneath the NTS area and to define and describe the likely direction of groundwater flow in each of these aquifers under predevelopment conditions. Predevelopment conditions assume equilibrium or a near equilibrium state in the groundwater flow system prior to any major changes prompted by human intervention, such as pumping and nuclear testing. Groundwater flow directions are determined by constructing potentiometric surface maps that are designed to conceptualize and describe flow within and between the major aquifers in the multi-aquifer flow system of the NTS area. Maps and their component hydraulic heads can be used as calibration targets for flow models and can help identify likely groundwater flow paths. Maps are developed to delineate the spatial extent of the major aquifers throughout the NTS and surrounding area and to convey the primary direction of flow within each aquifer. These maps also show areas of recharge and likely areas of lateral leakage into and out of each aquifer. A second set of maps delineates flow systems and tributary flow systems for the regional aquif...

show abstract

On the mechanism of the large hydraulic gradient under Yucca Mountain, Nevada

Cited by 2 publications

References 25 publications

Are Arid Regions Always that Appropriate for Waste Disposal? Examples of Complexity from Yucca Mountain, Nevada

Are Arid Regions Always that Appropriate for Waste Disposal? Examples of Complexity from Yucca Mountain, Nevada

Groundwater flow systems at the Nevada Test Site, Nevada: A synthesis of potentiometric contours, hydrostratigraphy, and geologic structures

Contact Info

Product

Resources

About