Geohydrology of rocks penetrated by test well USW H-4, Yucca Mountain, Nye County, Nevada
This report presents the results of hydraulic testing of rocks penetrated by USW H-4, one of several test wells drilled in the southwestern part of the Nevada Test Site, in cooperation with the US Department of Energy, for investigations related to the isolation of high-level radioactive wastes in volcanic tuffs of Tertiary age. All rocks penetrated by the test well to its total depth of 1219 meters were volcanic. Static water level was at a depth of 519 meters below land surface. Hydraulic-head measurements made at successively lower depths during drilling in this test hole indicate no noticeable head change. A radioactive-tracer, borehole-flow survey indicated that the two most productive zones in this borehole occurred in the upper part of the Bullfrog Member, depth interval from 721 to 731.5 meters, and in the underlying upper part of the Tram Member, depth interval from 864 to 920 meters, both in the Crater Flat Tuff. Hydraulic coefficients calculated from pumping-test data indicate that transmissivity ranged from 200 to 790 meters squared per day. The hydraulic conductivity ranged from 0.29 to 1.1 meters per day. Chemical analysis of water pumped from the saturated part of the borehole (composite sample) indicates that the water is typical of water produced from tuffaceous rocks in southern Nevada. The water is predominantly a sodium bicarbonate type with small concentrations of calcium, magnesium, and sulfate. The apparent age of this composite water sample was determined by a carbon-14 date to be 17,200 years before present. 24 refs., 10 figs., 8 tabs.
- Research Organization:
- Geological Survey, Denver, CO (United States); Fenix and Scisson, Inc., Mercury, NV (United States)
- DOE Contract Number:
- AI08-78ET44802
- OSTI ID:
- 59772
- Report Number(s):
- USGS/WRI--85-4030; ON: DE86004490
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
58 GEOSCIENCES
EXPERIMENTAL DATA
GEOLOGY
GROUND WATER
HIGH-LEVEL RADIOACTIVE WASTES
HYDRAULIC CONDUCTIVITY
HYDROLOGY
NEVADA TEST SITE
QUANTITATIVE CHEMICAL ANALYSIS
RADIOACTIVE WASTE DISPOSAL
SITE SELECTION
STRATIGRAPHY
TRACER TECHNIQUES
TUFF
WELL DRILLING
YUCCA MOUNTAIN
Yucca Mountain Project