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P.A. Glancy

Publications and source records attributed to P.A. Glancy.

5 recordsLinked to original sources
USGS1997

Volumetric analysis and hydrologic characterization of a modern debris flow near Yucca Mountain, Nevada

On July 21 or 22, 1984, debris flows triggered by rainfall occurred on the southern hillslope of Jake Ridge, about 6 km east of the crest of Yucca Mountain, Nevada. Rain gages near Jake Ridge recorded 65 mm and 69 mm on July 21, and 20 mm and 17 mm on July 22. Rates of rainfall intensity ranged up to 73 mm/h on the twenty-first, and 15 mm/h on the twenty-second. Digital elevation models with 2.0 m grid-node spacing, measured from pre-storm and post-storm aerial stereo-photographs, were used to map hillslope erosion and the downslope distribution of debris. Volumetric calculations indicate that about 7040 m 3 of debris was redistributed on the 49,132 m 2 hillslope study area during the two-day storm period. About 4580 m 3 (65%) of the eroded sediment was deposited within the study area and the remaining 35% was deposited outside the study area in a short tributary to Fortymile Wash and in the wash itself. The maximum and mean depths of erosion in the study area were about 1.8 m and 5 cm, respectively. The mean depths of erosion on the upper and middle hillslope were 27 cm and 4 cm, respectively. The mean depth of deposition on the lower hillslope was 16 cm. Analysis of the values of cumulative precipitation in the context of the precipitation-frequency atlas of the National Oceanic and Atmospheric Administration indicates that precipitation from the main storm on July 21 was more than double that expected, on average, once during a 100-year-period. The relations of precipitation intensity/duration, developed from data recorded at a nearby precipitation gage, indicate a storm interval of 500 years or greater. The amount of erosion caused by such a storm is primarily dependent on three variables; storm intensity, development of the drainage network on the hillslope, and the amount of available colluvium. Additionally, the erosive ability of successive storms of equal intensity will decrease because such storms would tend to progressively isolate and reduce the amount of colluvium available. The preservation of Pleistocene deposits on hillslopes of Yucca Mountain, in general, indicates that erosional events that strip 5% of the available hillslope colluvium must be quite rare. We conclude that the recurrence interval of an erosional event comparable to the July, 1984 event is probably much longer than 500 years.

Geomorphology↗
USGS1993

Streamflow and selected precipitation data for Yucca Mountain and vicinity, Nye County, Nevada, water years 1983-85

Streamflow and precipitation data collected at and near Yucca Mountain, Nevada, during water years 1983-85, are presented. The data were collected and compiled as part of the studies the U.S. Geological Survey is making, in cooperation with the U.S. Department of Energy, to characterize surface water hydrology in the Yucca Mountain area. Streamflow data include daily mean discharges and peak discharges at 4 complete-record gaging stations and peak discharges at 10 crest-stage, partial-record stations and 12 miscellaneous sites. Precipitation data include cumulative totals at 12 stations maintained by the U.S. Geological Survey and daily totals at 17 stations maintained by the Weather Service Nuclear Support Office, National Oceanic and Atmospheric Administration.

Open-File Report↗
USGS1975

Preliminary hydrogeologic appraisal of selected hydrothermal systems in northern and central Nevada

Several hydrothermal systems in northern and central Nevada were explored in a hydrogeologic reconnaissance. The systems studied comprise those at Stillwater and Soda Lakes-Upsal Hogback in the Carson Desert, Gerlach, Fly Ranch-Granite Range, and Double Hot Springs in the Black Rock Desert, Brady's Hot Springs, Leach Hot Springs in Grass Valley, Buffalo Valley Hot Springs, and Sulphur Hot Springs in Ruby Valley. The investigation focused on (1) delineating of areas of high heat flow associated with rising thermal ground water, (2) determining the nature of the discharge parts of the hydrothermal systems, (3) estimating heat discharge from the systems, (4) estimating water discharge from the systems, (5) obtaining rough estimates of, conductive heat flow outside areas of hydrothermal discharge, and (6) evaluating several investigative techniques that would yield the required information quickly and at relatively low cost. The most useful techniques were shallow test drilling to obtain geologic, hydraulic, and thermal data and hydrogeologic mapping of the discharge areas. The systems studied are in the north-central part of the Basin and Range province. Exposed volcanic rocks of latest Tertiary and Quaternary age are chiefly basaltic. Basaltic terranes are generally regarded as less favorable for geothermal resources than terranes that contain large volumes of young volcanic mocks of felsic to intermediate composition. Most of the known hydrothermal systems are associated with Basin and Range faults which are caused by crustal extension across the province. An area of high heat flow centered at Battle Mountain and possibly other areas of high heat flow may be related to crustal heat sources. However, some of the hydrothermal systems studied appear to be related to deep circulation of meteoric water in areas of 'normal' regional heat flow rather than to shallow-crustal heat sources. Discharge temperatures of thermal springs in the region range from slightly above mean annual air temperature (8?-12?C at most places) to boiling or slightly hotter. Geochemical data indicate that, in the major systems, subsurface temperatures at which thermal waters equilibrate with reservoir rocks range from 150? to more than 200?C. These data also indicate that the major systems are of the hot-water type rather than the vapor-dominated type. Depths of thermal-water circulation probably range from 2 to 6 kilometres in areas of 'normal' regional heat flow (~2 heatflow units) and from 1 to 3 kilometres in areas of high heat flow (~3-4 heat-flow units) such as near Battle Mountain. Most of the heat is discharged from the hydrothermal systems studied by (1) conduction through near-surface materials heated as a consequence of thermal-water convection, (2) convection as springflow, and (3) convection as steam discharge from spring pools, vents, fumaroles, and cracks. The mate of heat discharge by radiation from warm ground and by convection as lateral ground-water outflow is believed to be small in most systems and is not estimated. Estimates of net heat discharge from the systems studied range from about 0.8 x 106 calories per second at Buffalo Valley Hot Springs to about 14 x 106 calories per second at Stillwater. These estimates represent the approximate magnitude of the excess heat discharge from the thermal areas that results from the upward convection of hot water from deep sources. Water discharges from the hydrothermal systems by springflow, evapotranspiration, steam discharge, and lateral ground-water outflow. Estimated discharges range from about 0.2 x 106cubic metres per year from the Buffalo Valley Hot Springs system to about 3 x 106 cubic metres per year from the Stillwater system. In most of the hydrothermal systems studied and, by inference, in other similar systems in northern and central Nevada, the scale for potential .commercial development for production of electricity or for other uses may be constrained by the

Open-File Report↗