Data Series 190
U.S. GEOLOGICAL SURVEY
Data Series 190
Rainier Mesa is in the north-central part of the Nevada Test Site (NTS) in Nye County, southern Nevada (fig. 1). During 1957–92, 16 tunnels were mined in the Rainier Mesa area (U.S. Department of Energy, 2006). The five largest of these tunnel complexes (tunnels U-12b, U-12e, U-12g, U-12n, and U-12t) are shown in figure 1. Sixty nuclear devices were detonated in the tunnels and two nuclear devices were detonated in vertical shafts in the Rainier Mesa area (U.S. Department of Energy, 2000).
The U.S. Department of Energy (DOE), National Nuclear Security Administration Nevada Site Office, under its Environmental Restoration Program, has a long-term program to investigate and remediate radionuclide contaminants generated on the NTS as a result of nuclear testing. As part of the program, DOE is evaluating what risk these contaminants may pose to the public. To help accomplish this objective, ground-water levels are being compiled and analyzed to better understand the ground-water flow system. This report is the fourth in a series of studies by the U.S. Geological Survey (USGS), in cooperation with DOE, to analyze and quality assure historic water-level measurements in areas of testing on the NTS (Fenelon, 2000; Bright and others, 2001; Fenelon, 2005).
Rainier Mesa is a volcanic plateau at an altitude of about 7,500 ft above sea level. It receives about 12.5 in. of precipitation annually (Air Resources Laboratory, Special Operations and Research Division, 2005). About 2,000 to 5,000 ft of Tertiary volcanic rocks, consisting primarily of bedded and welded tuffs, underlie Rainier Mesa (Thordarson, 1966, p. 14). The lower units consist of low-permeability bedded tuffs that impede the downward flow of recharge water from the overlying fractured welded tuffs, creating a perched ground-water system in the volcanic rocks (Thordarson, 1966, p. 32–33). The water-level altitude in the perched system is irregular but generally ranges from about 5,700 to 6,200 ft above sea level. Beneath the volcanic rocks on Rainier Mesa are Paleozoic carbonate rocks, Mesozoic granites, and Paleozoic and Precambrian quartzite and argillite. A regional water table is found in the Paleozoic carbonate rocks at an altitude from about 4,200 to 4,300 ft above sea level and at depths ranging from about 1,400 ft off of the mesa to as great as 3,100 ft on top of the mesa.
This report documents and describes more than 1,200 water-level measurements made in the Rainier Mesa area from 1957 to 2005. Water levels were measured from 50 discrete intervals within 18 boreholes and from 4 tunnel sites. As part of the analysis, a systematic quality-assurance review of the USGS National Water Information System (NWIS) database was completed to remove or correct erroneous water-level data, and to add missing water-level measurements and well-site information. Well-completion data and borehole-lithologic descriptions were compiled from driller’s logs, well completion reports, and other published and unpublished information.
An interpretive Microsoft® Access database of Rainier Mesa water-level measurements was constructed that consists of several components. First, each water-level measurement was assigned multiple attributes to describe the hydrologic condition at the time of measurement. Second, each well hydrograph has a written narrative, which consists of information and comments about the well and water-level data for the well. Third, water-level data and site information from the NWIS database were merged into the water-level database to provide supporting information for use in interpreting water-level measurements in the vicinity of Rainier Mesa.
U.S.
Department of the Interior | U.S. Geological
Survey
Persistent URL: https://pubs.water.usgs.gov/ds2006190
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Page Last Modified: Monday, 28-Nov-2016 11:55:05 EST
