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Full-Text Articles in Earth Sciences
Effect Of Rivers On Groundwater Temperature In Heterogeneous Buried-Valley Aquifers: Extent, Attenuation, And Phase Lag Of Seasonal Variation, Nathan Lee Young
Effect Of Rivers On Groundwater Temperature In Heterogeneous Buried-Valley Aquifers: Extent, Attenuation, And Phase Lag Of Seasonal Variation, Nathan Lee Young
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The temperature of groundwater in aquifers is relatively stable when compared to the water temperature in surface-water bodies. However, in aquifers that are hydraulically connected to rivers that have water flux into the aquifer, the local aquifer temperature can show seasonal variation. This project focused on the thermally-altered, near-river zone of such an aquifer, and used numerical methods to examine the extent of seasonal variation in temperature into the aquifer, and the attenuation and phase shift of the signal with distance from the river. The results show that the extent of alteration by diffusive heat flow is negligible compared to …
Porosity And Permeability In Ternary Sediment Mixtures, Jason Dennis Esselburn
Porosity And Permeability In Ternary Sediment Mixtures, Jason Dennis Esselburn
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Porosity and permeability were measured in mixtures of fine, medium, and coarse sand, where the volume fraction of each of the three components was systematically varied. The porosity varies non-linearly with the volume fractions, and can be modeled with a piecewise-linear approach. The permeability also varies non-linearly with the volume fractions. Permeability can be modeled with the Kozeny-Carman equation using a recursive approach for computing the representative grain size from those of the components in the mixture.
Percolation-Based Techniques For Upscaling The Hydraulic Conductivity Of Semi-Realistic Geological Media, Bilal Idriss
Percolation-Based Techniques For Upscaling The Hydraulic Conductivity Of Semi-Realistic Geological Media, Bilal Idriss
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I tested three schemes for "upscaling" the hydraulic conductivity (K) on aquifers with bimodal K distributions. This bimodality (e.g., sand and mud deposits) was intended to capture typical geological conditions. Results were tested with a numerical model. Upscaling techniques used were inspired by schemes interpolating between arithmetic and harmonic means, but are based on percolation theory: 1) Critical path analysis (CPA), 2) Percolation path analysis (PPA, or standard scaling), and a novel scaling approach. Models chosen were both spatially correlated and uncorrelated, with important differences in critical percolation probabilities, Pc. Volume fractions Ps and 1-Ps (with Ps = sand volume …
Geostatistical Characterization Of Heterogeneity In The Aberjona River Aquifer, Woburn, Massachusetts, James Ralph Damico
Geostatistical Characterization Of Heterogeneity In The Aberjona River Aquifer, Woburn, Massachusetts, James Ralph Damico
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Ground water flow and contaminant transport patterns are largely controlled by the distribution of high- and low-permeability sediments. Therefore, an accurate description of the aquifer architecture is paramount to producing a representative ground water model. Models of contaminant fate and transport in the aquifer near Woburn, Massachusetts, have previously been created by others using a deterministic approach. As a complement to these prior studies, the proportions, geometry, and juxtaposition of the different lithofacies of the aquifer were statistically characterized for developing stochastic models for the aquifer system. The descriptions of lithology from boreholes were separated into eleven categories based primarily …