Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 56 for “"monitoring wells"”.
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Evaluation of purging methods when sampling for volatile organic compounds from low-yield monitoring Wells
… concentrations in a simulated monitoring well and how effective purging procedures were in providing representative samples. The experimental apparatus consisted of a teflon monitoring well complete with filter pack and bentonite seal constructed in a 10.2 cm diameter stainless …
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Sampling for volatile organic compounds from an aquitard: A field evaluation of screen length, purging method, and sampling time
… of representative ground-water samples from monitoring wells sited in an aquitard contaminated with volatile organic compounds (VOC); Two well-purging methods--(1) pump to the bottom of the screened interval and (2) pump to the top of the screened interval--were evaluated on three monitoring …
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Augmenting Indiana's Groundwater Level Monitoring Network: Optimal Siting of Additional Wells to Address Spatial and Categorical Sampling Gaps
Groundwater monitoring networks are subject to change by budgetary actions and stakeholder initiatives that result in wells being abandoned or added. A strategy for network design is presented that addresses the latter situation. It was developed in response to consensus in the state of Indiana …
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Quantifying groundwater discharge using thermal imagery and conventional groundwater exploration techniques for estimating the nitrogen loading to a meso-scale inland estuary
… groundwater piezometric mapping method used the monitoring wells around the bay to create an overall piezometric map of the near-bay area. Groundwater discharge was evaluated with respect to flow, concentration, and ultimately nitrogen loading to coastal waters. The results represent a snapshot …
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The optimal design of groundwater quality monitoring networks under conditions of uncertainty
The design of a monitoring network to provide initial detection of groundwater contamination at a waste disposal facility is complicated by uncertainty in both the characterization of the subsurface and the nature of the contaminant source. In addition, monitoring network design requires the …
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Evaluation of Groundwater Quality in Paleozoic Aquifers Using GIS Techniques, Central Texas
<p>Lab analyses of groundwater chemistry from monitoring wells completed in the Paleozoic Aquifers surrounding the Llano Uplift of Central Texas has been recorded and made available to the public through the Texas Water Development Board (TWDB). This study evaluated the results of these data dating …
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Possible Groundwater Denitrification in the Decorah Formation (Middle Ordovician)
… carbon and sulfur minerals. </p><p>Three shallow monitoring wells were installed and sampled, and sediment samples collected and analyzed to determine if denitrification is occurring within the Decorah Formation. This study showed that electron donors were present, but in low abundance, suggesting …
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Groundwater redox conditions at a petroleum contaminated site, Kuils River, South Africa : pathways for BTEX biodegradation
… taking place. Groundwater samples taken from 32 monitoring wells were analysed for NO₃-,NH₄+, Mn²+, Fe²+, SO₄²-, and ΣH₂S. Portable electrodes were used to make field measurements of electrical conductivity, redox potential, and pH. The variation and distribution of these redox-sensitive …
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Spatial and Temporal Variability of Subsidence: Fort Bend County, Texas
… of subsidence. GPS stations co-located with monitoring wells across the county indicate that periodic subsidence can occur when the potentiometric surface is more than 30 meters below land surface, whether groundwater levels are rising, falling or remain stable. Nine out of the fifteen GPS …
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Measurement and Modeling of Nitrate-Nitrogen Transport in Subsurface Bioreactors
… of the bioreactor were monitored in 16 monitoring wells installed at 1.5 m intervals and 0.76 m from each corner. A Finite Element Method routine was used for transient, two-dimensional groundwater flow, and the Random Walk Method was used for two-dimensional nitrate-N transport. The …
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Identifying A Mechanism For An Infiltration Threshold From The Sunflower River, Ms To The Underlying Alluvial Aquifer
… anomalously high water levels relative to other wells in the region. The purpose of this research was to identify the responsible mechanism for the apparent stage-threshold for surface-groundwater communication. Two possible mechanisms were considered: (1) scour of infiltration-limiting …
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Geotechnical investigation of Montrose wetland site
… taken from the site during installation of monitoring wells. Results from tests were used in the classification of soil. Additional samples were reconstructed to determine the permeability of the soil. These tests were performed in accordance with the American Society for Testing and …
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Groundwater contamination by selenium, nitrate, coliform bacteria, and volatile organic compounds in the Las Vegas Valley, Nevada, shallow aquifer zone
A network of 27 shallow groundwater monitoring wells in the Las Vegas Valley, Nevada, was sampled for selenium, nitrate, coliform bacteria and 37 volatile organic compounds. A distinct pattern of elevated levels of selenium, nitrates, and chloroform was observed in the developed portions of the …
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Hydrogeological and hydrogeochemical evaluation of a proposed flue gas cleanup dry waste disposal pit near Beulah, North Dakota
… and to develop a groundwater level and quality monitoring program for the landfill. These objectives were attained through installation of 18 monitoring wells and 3 test holes at the site.</p> <p>Based on groundwater level information, groundwater was found to flow to the west-northwest. Two …
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The Hydrogeologic effects of fly ash utilization in concrete at Coal Creek Station, Underwood, North Dakota
… flow patterns. </p><p> A comprehensive water monitoring network encompassing surface water, unsaturated zone water, and saturated zone water was designed for the site. Surface water quality was documented using a runoff collector and precipitation collector. soil moisture and ground water …
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Geohydrologic evaluation of a proposed coal-ash disposal site near Mandan, North Dakota
… mile west of Heskett Station. A total of 27 monitoring wells were installed at the proposed site. Monitoring well water levels indicated the presence of a static water table which is generally 30-40 feet below the ground surface. The groundwater beneath the proposed site is flowing …
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Quantification of acid loads and delineation of hydrochemical facies at a phreatic mine spoil aquifer
… acid producing and neutralizing reactions in monitoring wells down gradient from the injection site.;Low-frequency water chemistry was interpolated with natural cubic splines, resampled and multiplied by high-frequency flow to produce estimates of acid loads at high-frequency. …
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Estimation of leakage between the shallow and principal aquifers in the Las Vegas Valley Water District's main well field, Las Vegas, Nevada
… this contamination potential, water levels from monitoring wells in both aquifers were collected, a three dimensional finite difference ground-water flow model (MODFLOW) was developed to estimate volume and velocity of potential leakage, and water quality samples were collected; Water levels …
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Evidence of Hydro-Seismicity in the Tennessee Seismic Zone
… levels from 2 U.S. Geological Survey groundwater monitoring wells were also collected. Rainfall data were collected for the ETSZ. Reservoir, well and rainfall data were examined for correlation with earthquake occurrence rates. High Pearson correlation and anti-correlation coefficients (.7-.9) …
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Groundwater Modeling and Hydrogeological Parameter Estimation: Potomac Aquifer System, SWIFT Research Center
… TW-1 and observation head data from surrounding monitoring wells (MW) at the SWIFTRC were used to calculate hydrogeological parameters (transmissivity, hydraulic conductivity, specific storage, and storage coefficient). Two sets of data were analyzed from before and after TW-1 was rehabilitated …
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