Publications

Recent work has emphasized development of full‐range water‐retention functions that are applicable under both wet and dry soil conditions, but evaluation of such functions in numerical modeling has been limited. Here we show that simulations using the Rossi‐Nimmo (RN) full‐range function compared favorably with those using the common Brooks‐Corey function and that the RN function can...

Automated opaque flux-chamber measurements of soil carbon dioxide (CO2) flux (soil respiration) into the atmosphere at the Amargosa Desert Research Site show seasonal and diel cycles of soil respiration that are closely linked with soil temperature and soil moisture. During 1998, soil respiration increased with soil warming through spring, reaching a maximum rate (not counting...

Samples of water vapor in soil gas were obtained at the U.S. Geological Survey's Amargosa Desert Research Site in 1997 and 1998 from a depth of 1.5 m (meters) within a 300 m by 300 m grid that lies immediately to the south and west of a low-level radioactive-waste disposal site. The gas samples were analyzed for tritium. Fifty-eight samples were collected in May 1997; 61 samples were...

This data set contains the topographic and administrative hydrographic area boundaries for the Humboldt River Basin at 1:24,000-scale.

Tritium concentrations have been determined yearly since April 1994 from water-vapor samples collected at test hole UZB-2. The hole was drilled about 100 m (meters) south of the southwest corner of a commercial burial site for low-level radioactive wastes in September 1993. UZB-2 is equipped with ten 2.5-cm (centimeters) diameter air ports permanently installed in the unsaturated zone...

The isotopic composition of water in deep unsaturated zones is of interest because it provides information relevant to hydrologic processes and contaminant migration. Profiles of oxygen-18 (18O), deuterium (D), and tritium (3H) from a 110-meter deep unsaturated zone, together with data on the isotopic composition of ground water and modern-day precipitation, are interpreted in the...

Studies at the U.S. Geological Survey Amargosa Desert Research Site have focused on characterizing factors and processes that control transport and fate of contaminants in arid environments. This paper summarizes research results that have been published through 1998. Results have improved understanding of water and gas movement through a thick unsaturated zone, including the degree to...

Elevated tritium concentrations in the unsaturated zone at the Amargosa Desert Research Site (ADRS), immediately south and west of the low-level radioactive-waste burial site south of Beatty, Nevada, have stimulated research of processes that control the transport of tritium in arid unsaturated zones. In May 1997, 58 samples were collected from 1.5 m (meters) depth within a 250 m by 250...

In 1976, the U.S. Geological Survey (USGS) began studies of unsaturated-zone hydrology in the Amargosa Desert in support of the USGS Low-Level Radioactive Waste Program. In 1983, agreements with the Bureau of Land Management and the State of Nevada established two field study areas: a 16-ha area adjacent to a waste-burial facility 17 km south of Beatty and a 0.1-ha area about 3 km...

Pore water was extracted in March 1996 from cores collected from test holes UZB-1 and UZB-2 drilled November 1992 and September 1993, respectively, in the Amargosa Desert south of Beatty, Nevada. The test holes are part of a study to determine factors affecting water and gas movement through unsaturated sediments. The holes are about 100 meters south of the southwest corner of the fence...

The suitability of a waste-burial site depends on hydrologic processes that can affect the near-surface water balance. In addition, the loss of burial trench integrity by erosion and subsidence of trench covers may increase the likelihood of infiltration and percolation, thereby reducing the effectiveness of the site in isolating waste. Although the main components of the water balance...

As arid sites in the western United States are increasingly sought for disposal of the Nation's hazardous wastes and as volumes of locally generated wastes increase, concern about the potential effect of contaminants on environmental quality is being raised. Studies at the U.S. Geological Survey's Amargosa Desert research site near Beatty, Nevada are being done to evaluate mechanisms...