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Ground-water flow was simulated using variable-direction anisotropy in hydraulic conductivity to represent the folded, fractured sedimentary rocks that underlie the Shenandoah Valley in Virginia and West Virginia. The anisotropy is a consequence of the orientations of fractures that provide preferential flow paths through the rock, such that the direction of maximum hydraulic conductivity is oriented within bedding planes, which generally strike N30 deg E; the direction of minimum hydraulic conductivity is perpendicular to the bedding. The finite-element model SUTRA was used to specify variable directions of the hydraulic-conductivity tensor in order to represent changes in the strike and dip of the bedding throughout...
Categories: Publication; Types: Citation
The goal of my biodegradation research is to understand the processes controlling the rate of biodegradation of contaminants in the subsurface. This understanding will form the basis of methods to increase degradation rates without causing further degradation of groundwater quality. Recent work has focused on the fate of crude oil and agricultural nitrate contamination in the subsurface. Specific objectives for the crude oil research include: (a) determine the rate that contaminants are transported from the source zone; (b) provide an estimate of how long the spilled oil will continue to pollute the groundwater; and (c) determine the fate of products of biodegradation or so-called “secondary water quality impacts”...
Discrepancies in power plant CO2 emissions reported in the two data sets can be attributed, in part, to differences in both monitoring and accounting methods.
Categories: Publication; Types: Citation
Appreciable increases in the human population are expected to continue in the next 50 to 100 years. This population will require additional water for nonfungible (nonexchangeable) uses such as irrigated agriculture, livestock watering, domestic supply, and ecosystem support. Because most of the world's easily captured water is already identified and allocated, society must improve efficiency, change the present allocations, and/or develop new sources to meet the expected demands. As the global economy expands, apparently unrelated changes in policy or technology may have large, unexpected consequences for water resources. Foreshadowing these changes in stress on these resources will be the result of nonlinear thinking....
Categories: Publication; Types: Citation
A solar distillation loop apparatus includes a first pipe section disposed on a ground surface, the first pipe section including a substantially straight portion and elevated portions on each end of the substantially straight portion, an impure water inflow coupling at one end of the straight portion and an impure water outflow coupling at the other end of the straight portion; solar powered fans disposed in each of the elevated portions of the first pipe section; a second pipe section disposed under the ground surface beneath the first pipe section; and two substantially vertical pipe sections that connect respective ends of the second pipe section to respective ends of the first pipe section. C2 - September 19,...
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A method is presented for estimating seepage loss and streambed hydraulic conductivity along intermittent and ephemeral streams using streamflow front velocities in initially dry channels. The method uses the kinematic wave equation for routing streamflow in channels coupled to Philip's equation for infiltration. The coupled model considers variations in seepage loss both across and along the channel. Water redistribution in the unsaturated zone is also represented in the model. Sensitivity of the streamflow front velocity to parameters used for calculating seepage loss and for routing streamflow shows that the streambed hydraulic conductivity has the greatest sensitivity for moderate to large seepage loss rates....
Categories: Publication; Types: Citation
Lundquist, J.D., Dettinger, M., Stewart, I., and Cayan, D., 2008, Variability and trends in spring runoff in the western United States, in Waggoner, F., ed., Climate warming in western North America/Evidence and environmental effects: Utah State University Press, Chapter 5.
Categories: Publication; Types: Citation
Diurnal cycles of streamflow in snow-fed rivers can be used to infer the average time a water parcel spends in transit from the top of the snowpack to a stream gauge in the river channel. This travel time, which is measured as the difference between the hour of peak snowmelt in the afternoon and the hour of maximum discharge each day, ranges from a few hours to almost a full day later. Travel times increase with longer percolation times through deeper snowpacks, and prior studies of small basins have related the timing of a stream's diurnal peak to the amount of snow stored in a basin. However, in many larger basins the time of peak flow is nearly constant during the first half of the melt season, with little or...
In this paper an isotope-incorporated regional model is developed and utilized for simulations of an atmospheric river event that occurred in March 2005. A set of sensitivity experiments and comparisons with observations confirm that the kinetic isotopic exchange between falling droplets and ambient water vapor below the cloud base was mostly responsible for the initial enrichment and subsequent rapid drop of the deuterium abundance in precipitation observed during the event even under humid conditions. According to the budget analysis the increase in isotopic composition during the latter half of the event was primarily due to horizontal advection. The contribution of condensation from different atmospheric heights...
We have examined the evidence presented by Labat et al. and found that (1) their claims for a 4% increase in global runoff arising from a 1 °C increase in air temperature and (2) that their article provides the “first experimental data-based evidence demonstrating the link between the global warming and the intensification of the global hydrological cycle” are not supported by the data presented. Our conclusions are based on the facts that (1) their discharge records exhibit non-climatic influences and trends, (2) their work cannot refute previous studies finding no relation between air temperature and runoff, (3) their conclusions cannot explain relations before 1925, and (4) the statistical significance of their...
Categories: Publication; Types: Citation