Conference Papers

Lateral channel change on the mainly ephemeral Santa Cruz River, Pima County, Arizona, causes damage and has spawned costly efforts to control bank erosion. Aerial photographs, historical data, and field observations are used to document the history of channel change since 1936. Variability in the nature and degree of channel change over time and space is shown. Three major channel change processe

The gray, dark gray and black colors of the sediments and the presence of pyrite in the Carlin, Jerritt Canyon, Horse Canyon, Betze, and Gold Acres sediment-hosted disseminated gold (SHDG) deposits indicate that these rocks are not oxidized with respect to carbon and iron sulfide. The organic matter in the host rocks of SHDG deposits in north-central Nevada is cryptocrystalline graphite with dimen

As a major branch of computational hydraulics, notable advances have been made in numerical modeling of unsteady open-channel flow since the beginning of the computer age. According to the broader definition and scope of 'computational hydraulics,' the basic concepts and technology of modeling unsteady open-channel flow have been systematically studied previously. As a natural extension, computati

A field-scale soil linear was built to assess the feasibilty of constructing a liner to meet the saturated hydraulic conductivity requirement of the U.S. EPA (i.e., less than 1 ?? 10-7 cm/s), and to determine the breakthrough and transit times of water and tracers through the liner. The liner, 8 ?? 15 ?? 0.9 m, was constructed in 15-cm compacted lifts using a 20,037-kg pad-foot compactor and stand

In land burial schemes, compacted soil barriers with low hydraulic conductivity are commonly used in cover and liner systems to control the movement of liquids and prevent groundwater contamination. An experimental liner measuring 8 x 15 x 0.9 m was constructed with design criteria and equipment to simulate construction of soil liners built at waste disposal facilities. The surface of the liner wa

Surveys of sea otters (Enhydra lutris) conducted before, immediately after, or at the time of the TA^ Exxon Valdez oil spill were used to guide otter capture efforts and assess the immediate effects of the spill. Shoreline counts (by boat) of sea otters in Prince William Sound in 1984 suggested that a minimum of 4,500 sea otters inhabited nearshore waters of Prince William Sound. Areas of highest

Nearly 900 sea otter (Enhydra lutris) carcasses were recovered in or adjacent to coastal areas affected by the T/V Exxon Valdez oil spill. The time of carcass recovery and the condition of carcasses indicate that most oil spill-induced mortality occurred early in the response period. In fact, by 19 May about 70% of the carcasses had been found. The majority of the carcasses (56%) were from Prince

One objective of the International Falls and Roseau, Minnesota, CUSMAP projects was to develop a means of conducting regional-scale geochemical surveys in areas where bedrock is buried beneath complex glacially derived overburden. Partial analysis of B-horizon soils offered hope for detecting subtle hydromorphic trace-element dispersion patterns. An enzyme-based partial leach selectively removes m

After the T/V Exxon Valdez oil spill into Prince William Sound, the U.S. Fish and Wildlife Service and Exxon Company, U.S.A., began rescuing sea otters (Enhydra lutris). The primary objective of this operation was to capture live, oiled sea otters for cleaning and rehabilitation. Between 30 March and 29 May 1989, 139 live sea otters were captured in the sound and transported to rehabilitation cent

Tertiary strata of the La Honda basin are exposed in the Santa Cruz Mountains along the central California coast south of San Francisco. The basin fill has a composite thickness of more than 14,500 m and consists of sedimentary and volcanic rocks that in places rest on granitic basement rocks of the Salinia terrane. Paleogene strata are mainly turbidite sandstone and hemipelagic mudstone that accu

No abstract available 

Geographic information systems (GIS) allow an investigator the capability to merge and analyze numerous types of country-level resource data. Hypothetical resource analysis applications in Senegal were conducted to illustrate the utility of a GIS for development planning and resource monitoring. Map and attribute data for soils, vegetation, population, infrastructure, and administrative units were