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Preliminary development of the LBL/USGS three-dimensional site-scale model of Yucca Mountain, Nevada

This work was prepared under U.S. Department of Energy Contract No. DE-AC03-76SF00098, and DE-A108-78ET44802 administered by the Nevada Operations Office in cooperation with the U.S. Geological Survey, Denver.

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Abstract

A three-dimensional model of moisture flow within the unsaturated zone at Yucca Mountain is being developed at Lawrence Berkeley Laboratory (LBL) in cooperation with the U.S. Geological Survey (USGS). This site-scale model covers and area of about 34 km2 and is bounded by major faults to the north, east and west. The model geometry is defined (1) to represent the variations of hydrogeological units between the ground surface and the water table; (2) to be able to reproduce the effect of abrupt changes in hydrogeological parameters at the boundaries between hyrdogeological units; and (3) to include the influence of major faults. A detailed numerical grid has been developed based on the locations of boreholes, different infiltration zones, hydrogeological units and their outcrops, major faults, and water level data. Contour maps and isopatch maps are presented defining different types of infiltration zones, and the spatial distribution of Tiva Canyon, Paintbrush, and Topopah Spring hydrogeological units. The grid geometry consists of seventeen non-uniform layers which represent the lithological variations within the four main welded and non-welded hydrogeological units. Matrix flow is approximated using the van Genuchten model, and the equivalent continuum approximation is used to account for fracture flow in the welded units. The fault zones are explicitly modeled as porous medium using various assumptions regarding their permeabilities and characteristic curves. One-, two-, and three-dimensional simulations are conducted using the TOUGH2 computer program. Steady-state simulations are performed with various uniform and non-uniform infiltration rates. The results are interpreted in terms of the effect of fault characteristics on the moisture flow distribution, and on location and formation of preferential pathways.

Geospatial Extents

Additional Publication Details

Publication type:
Book
Title:
Preliminary development of the LBL/USGS three-dimensional site-scale model of Yucca Mountain, Nevada
Series number:
LBL-37356/UC-814
Year Published:
1995
Language:
English
Publisher:
Lawrence Berkeley Laboratory
Publisher location:
Berkeley, CA
Contributing office(s):
Denver Federal Center
Description:
xi, 69 p.
Number of Pages:
101
Country:
United States
State:
Nevada
Other Geospatial:
Yucca Mountain