Conference Papers

This paper briefly summarizes more than 470 measurements of local channel scour at bridge piers from 58 sites in 14 States. Relations between local scour and selected deterministic parameters are illustrated and discussed. Observed scour depths are compared with predicted values from two local scour prediction equations.

Plans for the nation's first high-level nuclear waste repository have called for permanently closing and sealing the repository soon after it is filled. However, the hydrologic environment of the proposed site at Yucca Mountain, Nevada, should allow the repository to be kept open and the waste retrievable indefinitely. This would allow direct monitoring of the repository and maintain the...

Disseminated coccidioidomycosis was diagnosed postmortem in six southern sea otters (Enhydra lutris nereis) found dying or dead along the Pacific Coast of California at San Luis Obispo County. These otters were found during winter or summer 1992, 1993, and 1994. Coccidioides immitis was identified by its morphology in tissue impression smears and by histopathology, and was confirmed by...

The U.S. Geological Survey (USGS) is field and laboratory testing the performance of several current meters used throughout the world for stream gaging. Meters tested include horizontal-axis current meters from Germany, the United Kingdom, and the People's Republic of China, and vertical-axis and electromagnetic current meters from the United States. Summarized are laboratory test...

In his introduction to the 1979 Symposium proceedings entitled “Shorebirds in Marine Environments," Frank Pitelka stressed the need for studies and conservation programs that spanned the western hemisphere (Pitelka 1979). In the 15 years since Pitelka's call to arms, the locations of many important migratory and wintering sites for shorebirds have been identified in the Americas (Senner...

Flooding of the Iowa River during July and August 1993 caused extensive contraction scour at the State Highway 99 bridge over the Iowa River at Wapello, Iowa. At least 3.3 m of piling under the footing of the second pier from the right (west) abutment were exposed. The scoured streambed did not fill in again after the flood receded, and a bathymetric survey in November 1993 showed that...

Critical and supercritical flows are generally considered to be rare occurrences in natural river channels. This paper presents data and results pertaining to the existence of measured critical and supercritical flows at gaging stations on the North Fork Toutle River (NFT) and Toutle River main stem (TR). The data set includes 930 discharge measurements made by the staff of the U.S...

Samples of organic matter from nine well-known geological units (Green River Fm., Tasmanian Tasmanite, Lower Toarcian Sh. of the Paris Basin, Duwi Fm., New Albany Sh., Monterey Fm., Herrin No. 6 coal, Eocene coal, and Miocene lignite from Kalimantan) were processed by density gradient centrifugation (DGC) to isolate the constituent macerals. Optimal separation, as well as the liberation...

The USGS, in cooperation with the COE, has designed and installed a system to continuously monitor changes in elevation of the river bed over the mussel bed located downstream of the Olmsted Locks and Dam project. The installed system utilizes a multi-transducer acoustic ranging system to provide river bed elevation measurements accurate to plus or minus 1 cm. The system is currently...

Field-collected hydraulic data can be used to compute roughness coefficients for channels with different hydraulic characteristics. Suggested criteria for the design of a roughness-coefficient study include: (1) location of the study reach close to an established streamflow-monitoring site with a stable high-flow stage-to-discharge relation; (2) uniform hydraulic conditions within, and...

Saline seeps are an increasingly serious problem in semi-arid regions of the southwestern United States. They result when excessive recharge of the shallow ground water in soils raises the water table locally to within one meter of the land surface, and the salinity of the shallow water is increased through evaporation. In this connection, a comprehensive study is being undertaken in...

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