Conference Papers

Water shortages in the southeastern United States have led to a need for more intensive management and usage of stormwater for beneficial uses such as irrigation. Harvesting of infiltrated stormwater from horizontal wells in sandy aquifer sediments beneath stormwater ponds has emerged as an alternative in need of evaluation. Cyanobacteria may proliferate in stormwater ponds; cyanotoxins...

SWI and SEAWAT are both computer codes designed to model variable-density systems. One of the options in SWI is to model Dupuit interface flow, where freshwater and seawater are separated by an interface. In this paper we compare seawater intrusion model results of SWI to model results of SEAWAT, which simulates full variable-density flow and transport. Results indicate that SWI is valid...

Glide cracks can result in full-depth glide avalanche release. Avalanches from glide cracks are notoriously difficult to forecast, but are a reoccurring problem in a number of different avalanche forecasting programs across a range of snow climates. Despite this, there is no consensus for how to best manage, mitigate, or even observe glide cracks and the potential resultant avalanche...

No abstract available.

A wide variety of pesticides are applied concurrently in agricultural and urban areas and transported off site dissolved in water and bound to sediments. But the exposure of aquatic and terrestrial organisms to current-use pesticides and the resulting effects are not well understood. One approach is to directly analyze tissue concentrations of contaminants. The overall objective of this...

Serpentinized ophiolitic rocks are juxtaposed against quartzofeldspathic rocks at depth across considerable portions of the Hayward and Calaveras Faults. The marked compositional contrast between these rock types may contribute to fault creep that has been observed along these faults. To investigate this possibility, we are conducting hydrothermal shearing experiments to look for changes...

A control volume mixed finite element scheme for a triangular discretization of a 2-D domain is presented; several control-volume scenarios for use with the scheme are explored.

The U. S. Geological Survey's Earth Resources Observation and Science Center has the responsibility to acquire, manage, and preserve our Nation's land observations. These records are obtained primarily from airplanes and satellites dating back to the 1930s. The ability to compare landscapes from the past with current information enables change analysis at local and global scales. With...

Hydrothermal systems currently are active near some gold deposits in northwestern Nevada. Possible links of these modern systems to gold mineralization were evaluated by chemically and isotopically analyzing water samples from the Brady, Dixie Valley, Humboldt House, San Emidio-Empire, Soda Lake, and Wabuska geothermal areas. In addition, quartz veins from Humboldt House and the adjacent...

The potable water system at Fort Knox is threatened by brine contamination from improperly abandoned natural gas exploration wells. The Fort Knox well field is located near the town of West Point, Kentucky, in the flood plain of the Ohio River. At the site, unconsolidated sediments approximately 30 – 40 m thick, overlie shale and porous limestone. Brine is believed to flow vertically...

echniques for processing frequency-domain electromagnetic (FDEM) data that address systematic instrument errors and random noise are presented, improving the ability to invert these data for meaningful earth models that can be quantitatively interpreted. A least-squares calibration method, originally developed for airborne electromagnetic datasets, is implemented for a ground-based...

This analysis of changes in the North American (Canada, Mexico, and the United States) ferroalloys industry between 1987 and 2007 includes the locations and types of ferroalloy plants in North America and the changes in production, imports, exports, pricing, and the structure of ownership since 1987, which was just prior to the implementation of the North American Free Trade Agreement...