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Title: 1983 biotic studies of Yucca Mountain, Nevada Test Site, Nye County, Nevada

Abstract

A 27.5-square-mile portion of Yucca Mountain on and adjacent to the US Department of Energy`s Nevada Test Site, Nye County, Nevada, is being considered as a potential location for a national high-level radioactive waste repository. Preliminary geologic and environmental characterization studies have been supported and more extensive studies are planned. Goals of the biotic surveys were to identify species of concern, describe major floral and faunal associations, and assess possible impacts of characterization and operational activities. Floral associations observed were characteristic of either the Mojave or Transition deserts that are widely distributed in southern Nevada. Diversity, in terms of total number of perennial species represented, was higher in Transition Desert associations than in Mojave Desert associations. Canopy coverage of associations fell within the range of reported values, but tended to be more homogeneous than expected. Annual vegetation was found to be diverse only where the frequency of Bromus rubens was low. Ground cover of winter annuals, especially annual grasses, was observed to be very dense in 1983. The threat of range fires on Yucca Mountain was high because of the increased amount of dead litter and the decreased amount of bare ground. Significant variability was observed in the distribution andmore » relative abundance of several small mammal species between 1982 and 1983. Desert tortoise were found in low densities comparable with those observed in 1982. Evidence of recent activity, which included sighting of two live tortoises, was found in five areas on Yucca Mountain. Two of these areas have a high probability of sustaining significant impacts if a repository is constructed. Regeneration of aboveground shrub parts from root crowns was observed in areas damaged in 1982 by seismic testing with Vibroseis machines. These areas, which had been cleared to bare dirt by passage of the machines, also supported lush stands of winter annuals.« less

Authors:
;
Publication Date:
Research Org.:
EG and G, Inc., Goleta, CA (United States). Energy Measurements Group
OSTI Identifier:
59080
Report Number(s):
EGG/10282-2031
ON: DE84017360
DOE Contract Number:
AC08-83NV10282
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: Apr 1984
Country of Publication:
United States
Language:
English
Subject:
05 NUCLEAR FUELS; 54 ENVIRONMENTAL SCIENCES; YUCCA MOUNTAIN; BASELINE ECOLOGY; PLANTS; WILD ANIMALS; SPECIES DIVERSITY; COMMUNITIES; ABUNDANCE; HIGH-LEVEL RADIOACTIVE WASTES; RADIOACTIVE WASTE DISPOSAL; SITE CHARACTERIZATION; Yucca Mountain Project

Citation Formats

O`Farrell, T.P., and Collins, E. 1983 biotic studies of Yucca Mountain, Nevada Test Site, Nye County, Nevada. United States: N. p., 1984. Web.
O`Farrell, T.P., & Collins, E. 1983 biotic studies of Yucca Mountain, Nevada Test Site, Nye County, Nevada. United States.
O`Farrell, T.P., and Collins, E. 1984. "1983 biotic studies of Yucca Mountain, Nevada Test Site, Nye County, Nevada". United States. doi:.
@article{osti_59080,
title = {1983 biotic studies of Yucca Mountain, Nevada Test Site, Nye County, Nevada},
author = {O`Farrell, T.P. and Collins, E.},
abstractNote = {A 27.5-square-mile portion of Yucca Mountain on and adjacent to the US Department of Energy`s Nevada Test Site, Nye County, Nevada, is being considered as a potential location for a national high-level radioactive waste repository. Preliminary geologic and environmental characterization studies have been supported and more extensive studies are planned. Goals of the biotic surveys were to identify species of concern, describe major floral and faunal associations, and assess possible impacts of characterization and operational activities. Floral associations observed were characteristic of either the Mojave or Transition deserts that are widely distributed in southern Nevada. Diversity, in terms of total number of perennial species represented, was higher in Transition Desert associations than in Mojave Desert associations. Canopy coverage of associations fell within the range of reported values, but tended to be more homogeneous than expected. Annual vegetation was found to be diverse only where the frequency of Bromus rubens was low. Ground cover of winter annuals, especially annual grasses, was observed to be very dense in 1983. The threat of range fires on Yucca Mountain was high because of the increased amount of dead litter and the decreased amount of bare ground. Significant variability was observed in the distribution and relative abundance of several small mammal species between 1982 and 1983. Desert tortoise were found in low densities comparable with those observed in 1982. Evidence of recent activity, which included sighting of two live tortoises, was found in five areas on Yucca Mountain. Two of these areas have a high probability of sustaining significant impacts if a repository is constructed. Regeneration of aboveground shrub parts from root crowns was observed in areas damaged in 1982 by seismic testing with Vibroseis machines. These areas, which had been cleared to bare dirt by passage of the machines, also supported lush stands of winter annuals.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 1984,
month = 4
}

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  • A portion of Yucca Mountain on and adjacent to the US Department of Energy`s Nevada Test Site, Nye County, Nevada, is being considered as a possible location for a national high-level radioactive waste repository. The geologic and environmental characteristics of the site are being investigated to determine its suitability for further characterization. Goals of biotic studies were to identify species of concern, describe major floral and faunal associations, determine exposure levels of external background radiation, and assess possible impacts of characterization and operational activities. The species composition of dominant small mammals inhabiting major vegetation associations in 1984 varied little comparedmore » with results of similar surveys conducted in 1982 and 1983. Total captures were lower and reproduction was apparently curtailed. Merriam`s kangaroo rat and the long tailed pocket mouse continued to be the most abundant species. Diversity of resident species did not differ significantly between the trapping lines. The composition and relative abundance of associated species was more variable. Western harvest mice were trapped for the first time, but pinyon mice, which were present in prior years, were not trapped. Five desert tortoises were observed during surveys of possible sites for repository surface facilities. 25 refs., 4 figs., 5 tabs.« less
  • In 1981 an extensive literature review was conducted to determine the current state of knowledge about the ecological characteristics of the Yucca Mountain study area and to identify what site-specific information was lacking. Based on the findings of the review a field study was initiated in 1982 to gather site-specific information on the ecological characteristics of the project area. The biota observed were representative of either the Mojave or Transition deserts that are widely distributed in southern Nevada and the arid Southwest. No unusual vegetation associations or assemblages of animals were observed. Based on observations of tracks and scats itmore » was concluded that low numbers of both mule deer and feral burros used the area seasonally, and that neither species should be severely threatened by the proposed activities. The Mojave fishhook cactus and desert tortoise, both under consideration for federal protection as threatened species, were found to occur in the study area. The former was distributed in notable densities on the rocky ridgelines of Yucca Mountain in areas that should not be greatly disturbed by site characterization or future repository activities. Evidence of desert tortoise was observed throughout the project area to elevations of 5240 ft; however, relative densities were estimated to be low (less than 20 per square mile). Physical destruction of soils and native vegetation was determined to be the most significant negative effect associated with current and proposed characterization activities. Solution holes in exposed flat rock on ridgelines that served as passive collectors of precipitation and runoff were the only sources of free water observed. While these water supplies were not adequate to support riparian vegetation, there was evidence that they served as an important ephemeral source of water for wildlife.« less
  • Reconnaissance refraction surveys consisting of a total 5 spreads were conducted in the Calico Hills, Wahmonie, and Yucca Mountain areas, southwestern Nevada Test Site (NTS). Data from Calico Hills and Wahmonie are generally high in quality; data from Yucca Mountain are for the most part low in quality. At Calico Hills and Wahmonie, special attention was focused on the possible occurrence of a major intrusive body at depth. At Calico Hills this occurrence is supported by an inferred dome-shaped velocity interface, possibly associated with the roof of an altered phase of argillite. however, if an intrusive body is present, itsmore » top must be buried deeper than 3 km or it must be so pervasively altered that its velocity is similar to that of the calcareous argillite encountered at the bottom of drill hole UE 25a-3. At Wahmonie, the seismic data suggest the occurrence of a massive lenticular unit within 60 m of the ground surface, probably consisting of argillite but possibly consisting of intensively altered intrusive rock. At Yucca Mountain, preliminary interpretations of the most reliable data suggest the occurrence of a major, steeply inclined velocity interface 500 m from the southwest end of the Yucca C spread. This interface may represent a major fault or erosional feature separating the Topopah Spring and Tiva Canyon Members with Paintbrush Tuff at depth. This interface is 800 m east of a previously mapped fault. On the basis of poor-quality data obtained at Yucca Mountain, the subsurface velocity distribution appears to be complex. For example, one spread near drill hole UE25 a-1 suggests not only a much thicker section of Tiva but also that this material is down thrown in the valley. This may suggest faulting with throws exceeding 100 meters or an equivalent erosional feature.« less
  • Yucca Mountain, located at the southwest corner of the Nevada Test Site in southern Nevada, is being investigated as a potential site for the storage of high-level radioactive waste. Sequences of ash-flow tuff like those at Yucca Mountain potentially could provide multiple geologic barriers against the release of nuclear waste, assuming that the geologic and hydrogeologic setting of the site are favorable. This report describes the geology of the Yucca Mountain site and presents preliminary conclusions on the basis of work in progress. Chapters are devoted to: geomorphology; stratigraphy; tectonic and volcanic framework of the candidate area; structural geology ofmore » the site and the site vicinity; seismicity of the candidate area and site; long-term regional stability with respect to tectonic and geological processes; and subsurface drilling and mining.« less
  • Recovery data for nine slug-tests in Well USW G-4 are reduced to determine hydraulic conductivity and storativity, assuming a homogeneous, isotropic, porous medium exists at the well. The purposes are to deduce these parameters, corroborate US Geological Survey estimates of parameters where possible, estimate the sensitivity of the inferences, and establish roughly how well these data fit the porous-medium model. This study was conducted to support assessment of the behavior of the groundwater system at Yucca Mountain near the Nevada Test Site in southwest Nevada. 13 refs., 30 figs., 3 tabs.