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Full-Text Articles in Physical Sciences and Mathematics

Experimental Limestone Dissolution And Changes In Multiscale Structure Using Small- And Ultra Small- Angle Neutron Scattering, Chad Alan Novack Dec 2015

Experimental Limestone Dissolution And Changes In Multiscale Structure Using Small- And Ultra Small- Angle Neutron Scattering, Chad Alan Novack

Masters Theses

Small angle neutron scattering (SANS), ultra-small angle neutron scattering (USANS), and backscatter electron (BSE) imaging, along with neutron computed tomography (NCT) were used in this study to experimentally quantify pore size, distribution, and connectivity of dissolved limestone geometries. Eight samples of Indiana limestone of two different initial permeabilities (2-4 mD and 70 mD ) [millidarcy] were reacted with HCl [hydrochloric acid] solutions at differing pH (2 and 4), and flow rates (0.1 and 10 cm3/min) [cubic centimeters per minute] to describe a broad range of parameters that affect limestone dissolution. NCT was first used to image the dissolution …


Using Digital Elevation Models Derived From Airborne Lidar And Other Remote Sensing Data To Model Channel Networks And Estimate Fluvial Geomorphological Metrics, Noah Slovin Nov 2015

Using Digital Elevation Models Derived From Airborne Lidar And Other Remote Sensing Data To Model Channel Networks And Estimate Fluvial Geomorphological Metrics, Noah Slovin

Masters Theses

Recent advances in remote-sensing technologies and analysis methods, specifically airborne-LiDAR elevation data and corresponding geographical information system (GIS) tools, present new opportunities for automated and rapid fluvial geomorphic (FGM) assessments that can cover entire watersheds. In this thesis, semi-automated GIS tools are used to extract channel centerlines and bankfull width values from digital elevation models (DEM) for five New England watersheds. For each study site, four centerlines are mapped. LiDAR and NED lines are delineated using ArcGIS spatial analyst tools with high-resolution (1-m to 2-m) LiDAR DEMs or USGS National Elevation Dataset (NED) DEMs, respectively. Resampled LiDAR decreases LiDAR DEM …


Impacts Of Three-Dimensional Non-Uniform Groundwater Flows For Quantifying Groundwater-Surface Water Interactions Using Heat As A Tracer, Jonathan M. Reeves Nov 2015

Impacts Of Three-Dimensional Non-Uniform Groundwater Flows For Quantifying Groundwater-Surface Water Interactions Using Heat As A Tracer, Jonathan M. Reeves

Masters Theses

Heat-as-a-tracer has become a common method to quantify surface water-groundwater interactions (SW/GW). However, the method relies on a number of assumptions that are likely violated in natural systems. Numerical studies have explored the effects of violating these fundamental assumptions to various degrees, such as heterogeneous streambed properties, two-dimensional groundwater flow fields and uncertainty in thermal parameters for the 1-dimensional heat-as-a-tracer method. No work to date has addressed the impacts of non-uniform, three-dimensional groundwater flows on the use of heat-as-a-tracer to quantify SW/GW interactions. Synthetic temperature time series were generated using COMSOL Multiphysics for a three-dimensional cube designed to represent a …


Measurement Of Hysteretic Shale Capillary Pressure – Saturation Relationships Using A Water Activity Meter, Brendan Michael Donnelly Aug 2015

Measurement Of Hysteretic Shale Capillary Pressure – Saturation Relationships Using A Water Activity Meter, Brendan Michael Donnelly

Masters Theses

Capillary pressure is the pressure difference across the interface of two immiscible fluids within a porous medium due to the interfacial tension between fluids and is related to both the properties of the fluids and the porous medium. Capillary pressure within a porous medium will change depending upon its degree of saturation. Understanding the relationship between capillary pressure and saturation for a rock allows for the modeling of multi-phase flow. Many traditional methods of measuring capillary pressure are unsuitable for the characterization of shale due to their inability to measure the high capillary pressures found within the small pores. Furthermore, …


Determining Discharge From The Fallasburg Dam And The Hydrology Of The Flat River Bypass Channel, Lowell, Michigan, Seth Kuiper May 2015

Determining Discharge From The Fallasburg Dam And The Hydrology Of The Flat River Bypass Channel, Lowell, Michigan, Seth Kuiper

Masters Theses

The Fallasburg Dam on the Flat River is required to release 110 cfs to the Bypass Channel. Residents have often reported low flows in the river, especially during the summer. The hydrology of the Bypass Channel downstream from the dam was investigated to determine whether the required flow was being released. Discharge measured at multiple transects reveal a shifts from gaining to losing conditions during the year. Gaining conditions occur during the spring and after significant rain events; losing conditions occur in the summer during dry periods. Five discharge measurements in 2013 and three in 2014 reveal flows less than …


Characterizing Groundwater Ch4 And 222rn In Relation To Hydraulic Fracturing And Other Environmental Processes In Letcher County, Ky, St. Thomas Majeau Ledoux May 2015

Characterizing Groundwater Ch4 And 222rn In Relation To Hydraulic Fracturing And Other Environmental Processes In Letcher County, Ky, St. Thomas Majeau Ledoux

Masters Theses

Hydraulic fracturing of shale deposits has greatly increased the productivity of the natural gas industry by allowing it to exploit previously inaccessible reservoirs. However, previous research has demonstrated that this practice can contaminate shallow aquifers with CH4 [methane] from deeper formations. This study compares concentrations and isotope compositions of CH4 sampled from domestic groundwater wells in Letcher County, Kentucky in order to characterize its occurrence and origins in relation to neighboring hydraulically fractured natural gas wells. Additionally, this study tests the reliability of 222Rn [radon] as an alternative tracer to CH4 in identifying processes of gas …


Hydrogeological Control On Spatial Patterns Of Groundwater Seepage In Peatlands, Danielle K. Hare Mar 2015

Hydrogeological Control On Spatial Patterns Of Groundwater Seepage In Peatlands, Danielle K. Hare

Masters Theses

Groundwater seepage to surface water is an important process to peatland ecosystems; however, the processes controlling seepage zone distribution and magnitude are not well understood. This lack of process-based understanding makes degraded peatland ecosystems difficult to restore and problematic for resource managers developing a sustainable design. Degraded peatlands, particularly abandoned cranberry farms, often have drainage ditches, applied surface sand, and decreased stream sinuosity to artificially lower the water table and support agriculture. These modifications disconnect the surface and groundwater continuum, which decreases thermal buffering of surface water significantly. The combination of a decreased influx of thermally buffered groundwater, a naturally …


Channel Morphology At A Meander Bend Chute Cutoff Partially Obstructed By Woody Debris, Drew Sobczak Jan 2015

Channel Morphology At A Meander Bend Chute Cutoff Partially Obstructed By Woody Debris, Drew Sobczak

Masters Theses

Field and flume experiments have examined the conceptual model for a meander bend in depth. Large woody debris piles are often associated with the development of a chute cutoff due to local aggradation and deflection of flow. This paper examines the bed morphology of a meander bend chute cutoff that is partially obstructed by woody debris. The bed morphology of the channel around the woody debris pile as well as the head of the cutoff are mapped. The pile is shielding the point bar immediately behind it and causing a narrow, deep channel on either side of the pile. The …