Conference Papers

A new depth-averaged model of debris-flow motion describes simultaneous evolution of flow velocity and depth, solid and fluid volume fractions, and pore-fluid pressure. Non-hydrostatic pore-fluid pressure is produced by dilatancy, a state-dependent property that links the depth-averaged shear rate and volumetric strain rate of the granular phase. Pore-pressure changes caused by shearing...

Adaptive management is different from other types of management in that it includes all stakeholders (versus only policy makers) in the process, uses resource optimization techniques to evaluate competing objectives, and recognizes and attempts to reduce uncertainty inherent in natural resource systems. Management actions are negotiated by stakeholders, monitored results are compared to

The U.S. Geological Survey conducted an environmental assessment of 198 catchments in a 54,000-km2 area of central Colorado, much of which is on Federal land. The Colorado Mineral Belt, a northeast-trending zone of historical base- and precious-metal mining, cuts diagonally across the study area. The investigation was intended to test the hypothesis that degraded water and sediment...

Envisioning and evaluating future scenarios has emerged as a critical component of both science and social decision-making. The ability to assess, report, map, and forecast the life support functions of ecosystems is absolutely critical to our capacity to make informed decisions to maintain the sustainable nature of our ecosystem services now and into the future. During the past two...

The Chesapeake Bay Program (CBP) is attempting to more strategically implement management actions to improve the health of the Nation’s largest estuary. In 2007 the U.S. Geological Survey (USGS) and U.S. Environmental Protection Agency (USEPA) CBP office began a joint effort to develop a suite of Internetaccessible decision-support tools and to help meet the needs of CBP partners to...

The surface of Titan, the largest icy moon of Saturn, is veiled by a very thick and hazy atmosphere. The Visual and Infrared Mapping Spectrometer onboard the Cassini spacecraft, in orbit around Saturn since July 2004, conduct an intensive survey of Titan with the objective to understand the complex nature of the atmosphere and surface of the mysterious moon and the way they interact...

This paper summarizes research from separate studies of fish passage over weirs (Larson et al., 2004; Litvan, 2006; Litvan, et al., 2008a-c) and weir hydraulics (Papanicolaou and Dermisis, 2006; Papanicolaou and Dermisis, in press). Channel incision in the deep loess region of western Iowa has caused decreased biodiversity because streams have high sediment loads, altered flow regimes...

Short-term weathering rates (chemical denudation) of primary weathering products were derived from an analysis of fluxes in precipitation and streamwater. Rainfall, streamflow (runoff), and related water quality have been monitored at the Panola Mountain Research Watershed (PMRW) since 1985. Regression relations of stream solute concentration of major ions including weathering products...

Much is known about the importance of the physical characteristics of salmonid habitat in Alaska and the Pacific Northwest, with far less known about the food sources and trophic processes within these habitats, and the role they play in regulating salmonid productivity. Freshwater food webs supporting salmonids in Alaska rely heavily on nutrient, detritus and prey subsidies from both...

The Illinois State Geologic Survey is conducting several ongoing CO2 sequestration projects that require geochemical models to gain an understanding of the processes occurring in the subsurface. The ISGS has collected brine and freshwater samples associated with an enhanced oil recovery project in the Loudon oil field. Geochemical modeling allows us to understand reactions with carbonate...

Alaska is already beginning to be affected by changes in global climate which make it a good location to study the feedback effects between climate, the water cycle and the carbon cycle. Using river dissolved elements and Sr isotopes we examine changes and/or differences in chemical weathering between watersheds in predominantly permafrost areas and glacial watersheds. Tributaries of the...

Understanding the lateral extent of a CO2 plume has important implications with regards to buying/leasing pore volume rights, defining the area of review for an injection permit, determining the extent of an MMV plan, and managing basin-scale sequestration from multiple injection sites. The vertical and lateral distribution of CO2 has implications with regards to estimating CO2 storage...