Conference Papers
Science Quality and Integrity
The USGS provides unbiased, objective, and impartial scientific information upon which our audiences, including resource managers, planners, and other entities, rely.
The USGS provides unbiased, objective, and impartial scientific information upon which our audiences, including resource managers, planners, and other entities, rely.
Browse almost 5,000 conference papers authored by our scientists and refine search by topic, location, year, and advanced search.
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Coastal Louisiana ecosystem assessment and restoration program: The role of ecosystem forecasting in evaluating restoration planning in the Mississippi River Deltaic Plain
The development of ecosystem management plans to restore and rehabilitate natural resources requires an understanding of how specific ecological mechanisms regulate the structure and function of ecosystems. To achieve restoration goals, comprehensive plans and engineering designs must effectively change environmental drivers at the regionallevel to reduce stress conditions at the local environment
Authors
Robert Twilley, Brady Couvillion, Imtiaz Hossain, Carola Kaiser, Alaina Owens, Gregory D. Steyer, Jenneke M. Visser
New approaches to stability analysis of steep coastal bluffs
We present a discussion on the limitations and needed improvements for existing slope stability analysis methods to accurately model steep coastal bluff failures resulting from both direct wave action at the toe in weakly cemented sands and precipitation-induced seepage failures in moderately cemented sands. Using a case-study detailing over 5 years of observations of coastal bluff erosion and lan
Authors
Brian D. Collins, Nicholas Sitar
Modeling of wave driven circulation and water quality in nearshore environments
In order to investigate the effects of nearshore discharges of water quality degrading substances and bacteria in coastal environments, models capable of predicting nearshore circulation due to local wave and tide conditions are required. One of the larger challenges to nearshore coastal modeling is accurately reproducing nearshore circulation due to wave action. Local wave action not only drives
Authors
Craig Jones, Stephen J. Angster
Experimental and field observations of breach dynamics accompanying erosion of Marmot Cofferdam, Sandy River, Oregon
A key issue faced in dam removal is the rate and timing of remobilization and discharge of stored reservoir sediments following the removal. Different removal strategies can result in different trajectories of upstream sediment transport and knickpoint migration. We examine this issue of for the Marmot Dam removal in Sandy River, Oregon, USA using both physical experiments and field studies accomp
Authors
G. E. Grant, Jeffrey D. G. Marr, C. Hill, S. Johnson, K. Campbell, O. Mohseni, J.R. Wallick, S.L. Lewis, E. A. O'connor, Jon J. Major
Probabilistic liquefaction hazard mapping
Many investigators have applied the liquefaction potential index (LPI) to map regional liquefaction hazard. LPI, which integrates the liquefaction potential of susceptible soil elements at a specific location into a single value, has been used to assess both (1) spatial variability of liquefaction potential, and (2) liquefaction potential of surficial geologic units. A promising application to map
Authors
Thomas L. Holzer
Spatial and temporal trends in nitrate concentrations in the eastern San Joaquin Valley regional aquifer and implications for fertilizer management
Ground-water withdrawals in the San Joaquin Valley totaled 64 million m3 /day (19 million ac-ft) in 2000, supplying about 45% of agricultural irrigation demand and about 80% of municipal supply (Hutson et al., 2004). Most of the population and ground-water use are in the eastern San Joaquin Valley, where reliance on ground water is expected to increase as a result of rapid population growth and li
Authors
Karen R. Burow, Christopher T. Green
Bedrock structural controls on the occurrence of sinkholes and springs in the Northern Great Valley Karst, Virginia and West Virginia
Recent geologic mapping at a scale of 1:24,000 has enabled a qualitative correlation of the occurrence of springs and sinkholes with bedrock structures and ground-water conditions in the northern Great Valley of Virginia and West Virginia. Sinkholes tend to be concentrated in zones of faulting, local minor folding, and clustered within susceptible bedrock units at the noses and axes of large plung
Authors
Daniel H. Doctor, David J. Weary, Randall C. Orndorff, George E. Harlow, Mark D. Kozar, David L. Nelms
Coral and crustose coralline algae disease on the reefs of American Samoa
Surveys for lesions in corals were conducted at seven sites around Tutuila in June 2004 and January 2005. The objectives of the study were to document the distribution and prevalence of disease in the major genera of corals and crustose coralline algae, systematically describe gross and microscopic morphology of lesions in reef corals and determine whether there are seasonal differences in prevale
Authors
G. Aeby, Thierry M. Work, D. Fenner, Eva DiDonato
Scientific objectives of the Gulf of Mexico gas hydrate JIP leg II drilling
The Gulf of Mexico Methane Hydrate Joint Industry Project (JIP) has been performing research on marine gas hydrates since 2001 and is sponsored by both the JIP members and the U.S. Department of Energy. In 2005, the JIP drilled the Atwater Valley and Keathley Canyon exploration blocks in the Gulf of Mexico to acquire downhole logs and recover cores in silt- and clay-dominated sediments interpreted
Authors
Emrys Jones, T. Latham, Daniel R. McConnell, Matthew Frye, J.H. Hunt, William Shedd, Dianna Shelander, Ray Boswell, Kelly K. Rose, Carolyn D. Ruppel, Deborah R. Hutchinson, Timothy S. Collett, Brandon Dugan, Warren T. Wood
Seeding hydrate formation in water-saturated sand with dissolved-phase methane obtained from hydrate dissolution: A progress report
An isobaric flow loop added to the Gas Hydrate And Sediment Test Laboratory Instrument (GHASTLI) is being investigated as a means of rapidly forming methane hydrate in watersaturated sand from methane dissolved in water. Water circulates through a relatively warm source chamber, dissolving granular methane hydrate that was pre-made from seed ice, then enters a colder hydrate growth chamber where h
Authors
William F. Waite, J.P. Osegovic, William J. Winters, M.D. Max, David H. Mason
Site selection for DOE/JIP gas hydrate drilling in the northern Gulf of Mexico
n the late spring of 2008, the Chevron-led Gulf of Mexico Gas Hydrate Joint Industry Project (JIP) expects to conduct an exploratory drilling and logging campaign to better understand gas hydrate-bearing sands in the deepwater Gulf of Mexico. The JIP Site Selection team selected three areas to test alternative geological models and geophysical interpretations supporting the existence of potential
Authors
Deborah Hutchinson, Dianna Shelander, J. Dai, D. McConnell, William Shedd, Matthew Frye, Carolyn D. Ruppel, R. Boswell, Emrys Jones, Timothy S. Collett, Kelly K. Rose, Brandon Dugan, Warren T. Wood
Forewarned is forearmed! Progress in development of the U.S. National Early Detection and Rapid Response System for invasive plants: Proposal for a North American early warning system for invasive plants
Currently, a National Early Detection and Rapid Response System (EDRR) for Invasive Plants is being developed in the United States. Conceptually, the system is a coordinated framework of local, state, and national interagency groups that is designed to prevent the establishment and spread of new invasive plants through early detection and reporting of suspected new invaders, identification and vou
Authors
Randy G. Westbrooks