Publications

Performance Assessment (PA) is the use of mathematical models to simulate the long-term behavior of engineered and geologic barriers in a nuclear waste repository; methods of uncertainty analysis are used to assess effects of parametric and conceptual uncertainties associated with the model system upon the uncertainty in outcomes of the simulation. PA is required by the U.S. Environmental Protecti

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No abstract available.

Prospect Gulch is a major source of iron, aluminum, zinc, and other metals to Cement Creek. Information is needed to prioritize remediation and develop strategies for cleanup of historical abandoned mine sites in Prospect Gulch. Chemical-constituent loads were determined in Prospect Gulch, a high-elevation alpine stream in southwestern Colorado that is affected by natural acid drainage from we

MOC3D is a general-purpose computer model developed by the U.S. Geological Survey (USGS) for simulation of three-dimensional solute transport in ground water (Konikow and others, 1996). The model is an update to the widely used USGS two-dimensional solute-transport model (MOC) and is implemented as an optional “package” for the ground-water flow model MODFLOW (Harbaugh and McDonald, 1996). Directl

The Abandoned Mine Lands (AML) Initiative is part of a larger strategy of the U.S. Department of the Interior and the U.S. Department of Agriculture to clean up Federal lands contaminated by abandoned mines.Thousands of abandond hard-rock metal mines (such as gold, copper, lead, and zinc) have left a dual legacy across the Western United States. They reflect the historic development of the west, y

Water-quality monitoring and hydraulic testing in fractured bedrock aquifers involves two important tasks: 1) identifying the hydraulically active fractures intersecting the borehole, and 2) inferring how the specific entry or exit ports in the borehole wall are connected to large-scale flow paths in the region surrounding the borehole. Effective characterization of fractured bedrock flow results

No abstract available.

The pesticides molinate, thiobencarb, and carbofuran are applied to rice (Oryza sativa L.) fields in the Sacramento Valley, California, each year during April through June. These pesticides are of concern because of their adverse effects on water quality and their potential adverse effects on aquatic life. Therefore, the California Regional Water Quality Control Board (CRWQCB) mandated the holding

Time domain surface electromagnetic soundings, borehole induction logs, and other borehole logging techniques are used to construct a realistic model for the shallow subsurface hydraulic properties of unconsolidated sediments in south Florida. Induction logs are used to calibrate surface induction soundings in units of pore water salinity by correlating water sample specific electrical conductivit

The Scanlon and Goldsmith [1997] paper contains a wealth of data that provides a useful contribution to the understanding of the spatial variability of matrix recharge in and around playa basins on the Southern High Plains. However, a significant clarification is necessary in the analysis of their "water flux" because in this system "water flux" must be placed in the context of both matrix and mac

Phenylurea and triazine herbicides, including some metabolites, were isolated from water and soil extracts by solid-phase extraction using a layered system of two extraction disks, a method called double-disk solid-phase extraction. The first disk consisted of strong anion exchange (SAX) of 10-μm styrene divinylbenzene (SDB) particles embedded in Teflon, and the second disk was a C18 disk of 10-μm