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Showing 1 to 20 of 32 for “"Phreatic"”.
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Recharge dynamics of a perched phreatic aquifer
… rates, timing, and mechanisms for a perched, phreatic aquifer. Recharge rates were estimated using fluid mass balance (FMB), integrated hydrograph separation (IHS), and innovative hydrograph manipulation techniques. Timing and mechanisms of recharge were analyzed using signal-processing and …
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Quantification of acid loads and delineation of hydrochemical facies at a phreatic mine spoil aquifer
Acid mine drainage geochemistry and in situ alkaline injection were investigated at the DLM coal mine, Alton West Virginia. These included spatial and temporal investigations into hydrochemical controls that were initiated with reclamation efforts. Approaches included the delineation of …
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Reliability Analysis of Tailings Storage Facility Embankments: Investigating the Effect of Zonation on Slope Stability
… and dilative responses, especially under varying phreatic conditions, and may lead to misleading assessments of safety and reliability. This study examines how stratigraphic zoning, defined as the subdivision of the embankment into zones of distinct hydraulic and mechanical characteristics, …
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Diagenetic controls of reservoir quality in the Mississippian Wayne Beds in the Williston Basin, Bottineau County, North Dakota
… cementation and micritization in the marine phreatic diagenetic environment. Hypersaline diagenesis caused minor dolomitization and anhydritization. Dissolution and minor cementation occurred in the freshwater vadose zone. Freshwater phreatic diagenesis resulted in mineralogical stabilization …
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Immediate and Long-Term Behavior of the Evanston Tunnel in Chicago Clay
… infiltration toward the tunnel under constant phreatic surface. The time-dependent settlement is primarily a function of the soil disturbance, OCR, and the volume of groundwater that infiltrates the tunnel.
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Cave Development in Strata of Ordovician-and Silurian-Devonian-Age in Highland County, Virginia
… cave development, while only 4% show active phreatic development, and 5% show characteristics of both active vadose and phreatic development. These observations are consistent with the fact that fissures, slot fissures, pits, and rooms—the types of caves most frequently found in Highland …
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The Investigation Of Okhissa Dam Using A Real-Time Monitoring System
… Dam is located in a region that contains both a phreatic aquifer and a confined aquifer. Prior to this investigation of Okhissa Dam artesian conditions were present. The Artesian conditions were alleviated by placing additional fill material on the downstream side. It is presumed these high …
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Modeling of surges caused by the release of breakup ice jams
… in three parts, namely the investigation of the phreatic water levels along an ice jam, the transport of accumulation ice covers, and the characteristics of surges and ice runs caused by the jam release. From this study, five different types of release mechanisms related to the break-up of ice …
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Depositional environments and diagenesis, Interlake Formation (Silurian), Williston Basin, North Dakota
… occlude primary porosity and formed in marine phreatic environments. Equant calcite cement formed in meteoric phreatic environments. Saddle dolomite cement formed after deep burial of Interlake rocks. </p>
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Lithofacies of the Pliocene-Pleistocene Lucayan Limestone, Great Abaco Island, Little Bahama Bank
… environments such as the vadose, meteoric, and phreatic zones. It is not possible to use the cement types to define past sea level positions. However, the cement types indicate periods of subaerial exposure that may have been a result of sea level fluctuations.</p> <p>The near surface carbonates …
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ΑΣΤΑΘΗΣ ΡΟΗ ΤΟΥ ΥΠΟΓΕΙΟΥ ΝΕΡΟΥ ΣΕ ΚΕΚΛΙΜΕΝΑ ΥΔΡΟΦΟΡΑ ΣΤΡΩΜΑΤΑ ΜΕ ΠΕΠΕΡΑΣΜΕΝΑ ΣΤΟΙΧΕΙΑ
… BOUNDARY CONDITIONS. THUS, THE AQUIFER CAN BE PHREATIC OR CONFINED, OR A COMBINATION OF THE TWO, LEAKY OR NON- LEAKY, UNDER TRANSIENT OR STEADY STATE CONDITIONS. PUMPING AND RECHARGE WELLS, SPRINGS, DRAINS, EVAPOTRANSPIRATION, LATERAL INFLOWS AND OUTFLOWS, STREAMS, LAKES AND NUMEROUS OTHER …
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Analysis of Transient Seepage Through Levees
… from negative (suction) to positive as the phreatic surface progresses through the levee. These changes can be calculated by finite element transient seepage analyses. In order for the transient seepage analysis to be valid, appropriate soil properties and initial conditions must be used. …
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Assessing Aquifer Vulnerability to Seawater Intrusion : Application of the GALDIT-Index to the Emilia-Romagna Coastline.
… two vulnerability maps, one for the surface phreatic aquifer and one for the underlying confined one. The results are relatively similar between those two maps and show that the coastline is highly vulnerable over a width of a few kilometres. The coastal plain, on the other hand, is …
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Speleogenesis of Critchfield Bat Caves and Associated Hydrogeology of the Northern Edwards Aquifer, Williamson County, Texas
… that they are all epigene caves with vadose and phreatic morphologies.</p> <h1><br /> <br /></h1> <p>.</p>
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Numerical and Experimental Analysis of the Effect of Faults in Open-Pit Mining Stability
… leach pad stability and well monitoring of the phreatic surface before and after the Hydro-Jex operation. Experimental and numerical results both indicate an improvement in mineral processing under the influence of Hydro-Jex. Numerical results show an insignificant decrease and significant …
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Wind-Driven Sea Surface Wave and Coastal Water Level Dynamics Across Different Spatial Scales
… fluid infiltrates the subsurface and raises the phreatic surface. The overall findings of this thesis contribute to understanding and improving prediction of coastal hazards and nearshore impacts in response to storm events and sea level rise at different spatial scales.
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Volcanic and sedimentary processes in phreatomagmatic volcanoes
… of phreatomagmatic activity are recognised- phreaticp phreatomagmatic (s. s. ) and surtseyan - based on the degree of involvement of magma with water and the depth of the interaction. Phreatic maars and phreatomagmatic tuff-rings are underlain by pipe-like diatremes but these structures are …
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Speleogenesis and Delineation of Megaporosity and Karst Geohazards Through Geologic Cave Mapping and LiDAR Analyses Associated with Infrastructure in Culberson County, Texas
… hypogenetic exposures in the west and epigenetic phreatic / vadose exposures in the east. Additionally, supplementary LiDAR data was used to create digital elevation models (DEM) so that the effectiveness of physical field surveys versus remote sensing techniques could be determined. Previous …
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Cementation and dolomitization of Mississippian limestones, Kentucky and Virginia
… limestone is up to 1000 m thick. Here, phreatic meteoric diagenesis in more distal parts of the aquifer caused high-Mg calcite and aragonite grains to be leached, while isotopically light, fine dolomite (δ¹⁸O -1.7 to -6.7 per mil; δ¹³C 2.7 to -5.3 per mil) replaced muddy carbonates in a …
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Hydrogeological investigation of the Naukluft mountains, southwest Namibia
… third, is the Namib Aquifer, which is a porous phreatic aquifer to the west and south of the Naukluft Karst Aquifer, confined to the alluvial formations of the Tsondab and Tsauchab ephemeral rivers. The Naukluft Karst Aquifer is a high rainfall and discharge area in terms of rainfall; however, …
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