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Many technologies for the clean-up of petroleum-hydrocarbon contaminated sites depend on microbial degradation of the pollutant. In these technologies the site may be modified to enhance microbial activity, or may simply be monitored for naturally occurring microbial activity. In either case, an important aspect of site assessment for these technologies...

As part of the Installation Restoration Program, Cecil Field Naval Air Station, Jacksonville, Florida, is considering remedialaction alternatives to control the possible movement of contaminants from sites that may discharge to the surface. This requires a quantifiable understanding of ground-water flow through the surficial aquifer system and how the system...

At the request of the Bureau of Land Management, the U.S. Geological Survey assessed the Lake Valley Area of Critical Environmental Concern (ACEC), which includes the historic Lake Valley townsite and silver-manganese mining district, for undiscovered mineral resources. The Lake Valley ACEC is along the southeastern margin of the Black...

Tilt has been the nemesis of horizontal long period seismology since its inception. Modern horizontal long period seismometers with their long natural periods are incredibly sensitive to tilt. They can sense tilts smaller than 10-11 radians. To most readers, this is just a very very small number, so we will...

The objective of this study was to parameterize and implement the Century ecosystem model for an eroding, cultivated site near Senatobia, in Panola County, Mississippi, in order to understand the loss and replacement of soil organic carbon on an eroding cropland. The sites chosen for this study are located on...

This chapter establishes the relationship among earthquake source parameters and the generation, propagation, and run-up of local tsunamis. In general terms, displacement of the seafloor during the earthquake rupture is modeled using the elastic dislocation theory for which the displacement field is dependent on the slip distribution, fault geometry, and...

Knowledge of the spatial distribution of snow water equivalence (SWE) is necessary to adequately forecast the volume and timing of snowmelt runoff.  In April 1997, peak accumulation snow depth and density measurements were independently taken in the Loch Vale watershed (6.6 km2), Rocky Mountain National Park, Colorado.  Geostatistics and classical...

In 1996, seven cores were recovered in western Collier County, southwestern Florida, to acquire subsurface geologic and hydrologic data to support ground-water modeling efforts. This report presents the lithostratigraphy, X-ray diffraction analyses, petrography, biostratigraphy, and strontium-isotope stratigraphy of these cores. The oldest unit encountered in the study cores is an...

Reflection-mode borehole radar and transmission-mode radar tomograms image heterogeneity in the electromagnetic properties of rock. Heterogeneity may be produced by interfaces between different rock types, foliation, and fracturing. In crystalline rock, hydraulic flow is primarily through fracture networks rather than through the rock matrix. Borehole radar methods have been...

Determining the likelihood that groundwater contains elevated concentrations of contaminants can help water resource managers protect drinking water supplies. For example, this information is useful for selecting new sites for drinking water sources and designing more cost-effective monitoring strategies for existing sources. Groundwater vulnerability has typically been assessed using largely...

The Hydrological Simulation Pro-gram-FORTRAN (HSPF) was applied to an urban drainage basin in Jefferson County, Ky to integrate the large amounts of information being collected on water quantity and quality into an analytical framework that could be used as a management and planning tool. Hydrologic response units were developed using...

Prior research developed a cellular automaton model, that was calibrated by using historical digital maps of urban areas and can be used to predict the future extent of an urban area. The model has now been applied to two rapidly growing, but remarkably different urban areas: the San Francisco Bay...

The use of environmental tracers in characterization of ground-water systems is investigated through mathematical modeling of ground-water age and atmospheric tracer transport, and by a field study at the Mirror Lake site, New Hampshire. Theory is presented for modeling ground-water age using the advective-dispersive transport equation. The transport equation includes...

Limestone treatment systems can be effective for remediation of acidic mine drainage (AMD) that contains moderate concentrations of dissolved O2 , Fe3+ , or A13+ (1‐5 mg‐L‐1 ). Samples of water and limestone were collected periodically for 1 year at inflow, outflow, and intermediate points within underground, oxic limestone drains...

The chemical composition of the Cu-mining-related acidic ground water (pH ∼ 3.5 to near neutral) in Pinal Creek Basin, Arizona has been monitored since 1980. In-situ experiments are planned using alluvial sediments placed in the ground-water flow path to measure changes in mineral and...

Studies of Yucca Mountain, Nevada, as a potential geologic nuclear-waste repository began in the late 1970s and continued to 1988 when the U. S. Nuclear Regulatory Commission determined that the quality assurance (QA) programs in place were not adequate and demanded restructuring to a new QA program. The new QA...

In order to study the origin of the Grande Ronde basalts (GRs) erupted in the climax stage of the Columbia River basalts (CRBs), we carried out high pressure melting experiments on four of the most primitive rock compositions representing the Yakima group of the CRBs. The voluminous GRs (constituting >80 vol% of CRBs) are...

Following the 1994 Mw=6.7 Northridge earthquake, a 65‐km‐long, north‐south array of 11 geodetic monuments was established across the rupture. The array was surveyed with GPS ten times in the 4.25 yr after the earthquake. Although there is evidence for modest nonlinear postseismic relaxation in the first few weeks after the...

A linear array of 15 geodetic monuments was installed in 1993 across the rupture zone of the 1964 Alaska earthquake (Mw = 9.2). The array extends from Middleton Island (at the edge of the continental shelf and 80 km from the Alaska‐Aleutian trench) to north of Palmer, Alaska (380 km from...

We discuss three interconnected processes that occur during continental compression and extension: delamination of the lower crust and sub-crustal lithosphere, escape tectonics (i.e., lateral crustal flow), and crustal uplift. We combine calculations of lithospheric viscosity–depth curves with geologic observations and seismic images of...

The tiger (Panthera tigris) is an endangered, large felid whose demographic status is poorly known across its distributional range in Asia. Previously applied methods for estimating tiger abundance, using total counts based on tracks, have proved unreliable. Lack of reliable data on tiger densities not only has constrained our ability...

Understanding evolutionary consequences of intermittent breeding (nonbreeding in individuals that previously bred) requires investigation of the relationships between adult breeding state and two demographic parameters: survival probability and subsequent breeding probability. One major difficulty raised by comparing the demographic features of breeders and nonbreeders as estimated from capture–recapture data is...

Previous studies have revealed the close coupling of components of annual streamflow hydrographs and the germination and establishment of Populus species. Key hydrograph components include the timing and magnitude of flood peaks, the rate of decline of the recession limb, and the magnitude of base flows. In this...

Findings of the Great Basin Regional Aquifer System Analysis (RASA) are summarized. The Great Basin RASA study encompasses an area of about 140,000 square miles. Regional hydrology and ground-water hydrology of the area are described. Five models of basin-fill aquifers, a ground-water flow model of the Fish Springs system, and...

Core samples, cuttings, and numerous geophysical logs obtained from the 1560 ft (475.5 m) core hole drilled at 98th Street on the west side of Albuquerque provide key stratigraphic and hydraulicproperty information for the upper clastic sediments of the Santa Fe Group, which form the principal aquifer in the region....