| Abstract: | The unsaturated volcanic tuffs beneath Yucca Mountain, Nevada, are being evaluated as a host rock for a potential repository for high-level radioactive waste. A conceptual hydrologic model is proposed to describe the flow of fluids through these rocks. Thickness of the unsaturated zone is about 500 to 750 meters and consists of three welded units interlayered with two nonwelded units. Compared to nonwelded units, welded units have low matrix porosities and permeabilities, high fracture densities, and high bulk hydraulic conductivities. The principal repository area is bounded by normal fault zones. Of the average annual precipitation of 150 millimeters per year, 0.5 to 4.5 millimeters per year becomes net infiltration. Percolation through the matrix of the welded units is principally vertical and is less than 1 millimeter per year. Percolation through nonwelded units occurs both vertically and laterally and has variable rates (0.1 to 100 millimeters per year). Fracture flow is predominant in the uppermost welded unit during intense pulses of infiltration, but is insignificant in the welded unit that forms the potential host rock. Lateral flow in the upper nonwelded unit, enhanced by existence of a capillary barrier, probably is the factor controlling the low fluxes in the host rock and relatively high fluxes in the structural features. (USGS) |
| Genre: | USGS Numbered Series |
| ProdID: | 28749 |
| Citation Author: | Montazer, P. M.; Wilson, W. E. |
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| Citation Language: | ENGLISH |
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| Citation Phsyical Description: | iv, 55 p. :ill., map ;28 cm. |
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| Citation Publisher: | U.S. Geological Survey, |
| Citation Series: | Water-Resources Investigations Report |
| Citation Series Code: | WRI |
| Citation Series Number: | 84-4345 |
| Citation Search Results Text: | Conceptual hydrologic model of flow in the unsaturated zone, Yucca Mountain, Nevada; 1984; WRI; 84-4345; Montazer, P. M.; Wilson, W. E. |
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| Citation Year: | 1984 |
| Type: | citation/reference |
| Text: | Conceptual hydrologic model of flow in the unsaturated zone, Yucca Mountain, Nevada; 1984; WRI; 84-4345; Montazer, P. M.; Wilson, W. E. |
| URL (THUMBNAIL): | http://pubs.usgs.gov/wri/1984/4345/report-thumb.jpg |
| URL (DOCUMENT): | http://pubs.usgs.gov/wri/1984/4345/report.pdf |
| Date Other: | Sat, 1 Jan 1994 00:00 -0600 |
| Publisher: | U.S. Geological Survey, |
