Brad T Gooch - Academia.edu (original) (raw)

Papers by Brad T Gooch

Research paper thumbnail of Determining initial viability of local scale managed aquifer recharge projects in alluvial deposition systems

Correspondence to: Alisha Rodriguez amarodriguez@ucdavis.edu Copyright: © 2021 by the authors. L... more Correspondence to: Alisha Rodriguez amarodriguez@ucdavis.edu Copyright: © 2021 by the authors. Licensee Associazione Acque Sotterranee. This is an open access article under the CC BY-NC-ND license: http://creativecommons.org/licenses/bync-nd/4.0/ Citation: Alisha Rodriguez, Andrew Calderwood, Brad T. Gooch, Maribeth Kniffin, Laura Foglia, (2021) Determining initial viability of local scale managed aquifer recharge projects in alluvial deposition systems. Acque Sotterranee Italian Journal of Groundwater, 10(2), 7 18, https://doi.org/10.7343/as-2021-500 ARTiCLE inFo

Research paper thumbnail of West Florida Shelf: A natural laboratory for the study of ocean acidificiation

Research paper thumbnail of Potential groundwater and heterogeneous heat source contributions to ice sheet dynamics in critical submarine basins of East Antarctica

Geochemistry, Geophysics, Geosystems, 2016

Research paper thumbnail of Shake, Rupture And Flow: Hydraulic Constraints On The Formation Of Europa's Chaos

ABSTRACT Europa’s chaos terrains may have formed above shallow water lenses formed by melting of ... more ABSTRACT Europa’s chaos terrains may have formed above shallow water lenses formed by melting of the upper ice shell with ascending thermo-compositional plumes. A key factor in the creation of chaos terrain may be dramatic disruption and collapse of the ice lid above the forming melt lens along with potentially violent mixing upon its rupture; this is analogous to the collapse of terrestrial ice shelves in which massive ice bodies disintegrate in a few days. At Thera Macula, there is evidence for modification by water immediately external to the scarp that bounds the collapsed region. Since water runs either subaerially down hill or from high pressure to low when below or within ice, the swollen appearance of bands entering Thera Macula, which are uphill in terms of hydraulic and topographic gradients, raises the possibility that this steep scarp represents the place where the lens initially broke. As the ice lid ruptures, the overpressure within the lens may create sufficient pressure within the fracture to drive water through it, allowing water to escape into and modify surrounding terrain. Similar effects are seen when aquifers or subglacial water sources are tapped: water flows up the pipe until the pressure in the water body is relieved and the hydraulic “pressure head” in the pipe is lowered. We have modeled the hydraulic potential associated with a rupturing lens in order to investigate the range of parameters for overpressure, fracture width, and lid thickness that could produce such modification as is observed at Thera Macula. These place important constraints on the pressure within the lens and the energetics of a collapse event. These estimates may explain how ice masses within chaos are initially disrupted and provide a means for quantifying the vigor of surface-subsurface mixing that could be critical to Europa’s habitability.

Research paper thumbnail of Ground Penetrating Radar (GPR) Imaging to Distinguish Active from Inactive Sinkholes in Covered Karst Terrain: Results from Field Data and 3D FDTD Modeling

Ground penetrating radar (GPR) is widely used to identify locations of sinkholes in covered karst... more Ground penetrating radar (GPR) is widely used to identify locations of sinkholes in covered karst terrain in Florida. Some sinkholes serve as hydraulic conduits between the surficial and underlying aquifers. Their role is critical in determining the surficial aquifer response to pumping in deeper aquifers. Improved methods for discriminating between hydraulically active sinkholes and plugged sinkholes could help regional water

Research paper thumbnail of Exploring Subglacial Lake Connectivity via Groundwater Aquifers in the Dome C Region, East Antarctica

ABSTRACT Subglacial lakes lying under the Antarctic Ice Sheet form part of a dynamic, interconnec... more ABSTRACT Subglacial lakes lying under the Antarctic Ice Sheet form part of a dynamic, interconnected hydraulic system. Most research exploring the nature of this system has focused on flow along the ice-bed interface, neglecting the effects of groundwater transport, as such systems are thought to lack the transmissivity necessary to accommodate the inferred meltwater volume. In the Dome C region of East Antarctica, however, inferred melt water volumes are relatively low due to proximity to the ice divide and hydraulic gradients are relatively high due to steep subglacial bedrock topography, such that groundwater flow might be viable as a dominant means of water transport. This region contains many small subglacial lakes residing in bedrock depressions of steep basal topography. Preliminary analysis of radar sounding data does not always reveal an obvious hydraulic connection between these lakes despite readily apparent sources of melt feeding these bodies. Here we test several simple models for groundwater flow, including both fractured rock and porous media systems using ice-surface and bedrock geometry inferred from radio-echo sounding data and a published map of melt rates, with the purpose of defining a region in which a groundwater system can account for the majority of the water budget. We then compare these results against maps of basal reflectivity and subglacial lake distribution, as determined from radar sounding data. Areas in which groundwater flow is the dominant process will lack basal lubrication and demonstrate low basal reflectivities, but could still contain small subglacial lakes. While not spatially extensive with respect to the ice sheet, these groundwater-dominated areas could occupy the headwaters of most glacial catchments representing a unique and relatively stable subglacial environment.

Research paper thumbnail of Possible groundwater dominance in the subglacial hydrology of ice sheet interiors: example at Dome C, East Antarctica

The Cryosphere Discussions, 2016

We hypothesize that groundwater systems may be the main water transport mechanism over (distribut... more We hypothesize that groundwater systems may be the main water transport mechanism over (distributed, inefficient) water sheets at large scales in the interiors of ice sheets where melt rates are very low. We compare melt rate magnitudes to potential groundwater volume fluxes and also calculate the theoretical transmissivity ranges of subglacial water sheet and groundwater flow systems. Theoretical groundwater systems are on par with or are more transmissive than water sheets for the upper half of the permeability spectrum. In addition, we develop a 2D cross-sectional subglacial flow path model that connects subglacial lakes near Dome C, East Antarctica. This model integrates subglacial water sheet flux and hypothetical groundwater flow forcing, better bridging two historically disparate modeling frameworks – subglacial hydrology and ice sheet hydrogeology. Our model results suggest that the water sheet thickness can be highly dependent on groundwater flux and that the water sheet tr...

Research paper thumbnail of Determining initial viability of local scale managed aquifer recharge projects in alluvial deposition systems

Correspondence to: Alisha Rodriguez amarodriguez@ucdavis.edu Copyright: © 2021 by the authors. L... more Correspondence to: Alisha Rodriguez amarodriguez@ucdavis.edu Copyright: © 2021 by the authors. Licensee Associazione Acque Sotterranee. This is an open access article under the CC BY-NC-ND license: http://creativecommons.org/licenses/bync-nd/4.0/ Citation: Alisha Rodriguez, Andrew Calderwood, Brad T. Gooch, Maribeth Kniffin, Laura Foglia, (2021) Determining initial viability of local scale managed aquifer recharge projects in alluvial deposition systems. Acque Sotterranee Italian Journal of Groundwater, 10(2), 7 18, https://doi.org/10.7343/as-2021-500 ARTiCLE inFo

Research paper thumbnail of West Florida Shelf: A natural laboratory for the study of ocean acidificiation

Research paper thumbnail of Potential groundwater and heterogeneous heat source contributions to ice sheet dynamics in critical submarine basins of East Antarctica

Geochemistry, Geophysics, Geosystems, 2016

Research paper thumbnail of Shake, Rupture And Flow: Hydraulic Constraints On The Formation Of Europa's Chaos

ABSTRACT Europa’s chaos terrains may have formed above shallow water lenses formed by melting of ... more ABSTRACT Europa’s chaos terrains may have formed above shallow water lenses formed by melting of the upper ice shell with ascending thermo-compositional plumes. A key factor in the creation of chaos terrain may be dramatic disruption and collapse of the ice lid above the forming melt lens along with potentially violent mixing upon its rupture; this is analogous to the collapse of terrestrial ice shelves in which massive ice bodies disintegrate in a few days. At Thera Macula, there is evidence for modification by water immediately external to the scarp that bounds the collapsed region. Since water runs either subaerially down hill or from high pressure to low when below or within ice, the swollen appearance of bands entering Thera Macula, which are uphill in terms of hydraulic and topographic gradients, raises the possibility that this steep scarp represents the place where the lens initially broke. As the ice lid ruptures, the overpressure within the lens may create sufficient pressure within the fracture to drive water through it, allowing water to escape into and modify surrounding terrain. Similar effects are seen when aquifers or subglacial water sources are tapped: water flows up the pipe until the pressure in the water body is relieved and the hydraulic “pressure head” in the pipe is lowered. We have modeled the hydraulic potential associated with a rupturing lens in order to investigate the range of parameters for overpressure, fracture width, and lid thickness that could produce such modification as is observed at Thera Macula. These place important constraints on the pressure within the lens and the energetics of a collapse event. These estimates may explain how ice masses within chaos are initially disrupted and provide a means for quantifying the vigor of surface-subsurface mixing that could be critical to Europa’s habitability.

Research paper thumbnail of Ground Penetrating Radar (GPR) Imaging to Distinguish Active from Inactive Sinkholes in Covered Karst Terrain: Results from Field Data and 3D FDTD Modeling

Ground penetrating radar (GPR) is widely used to identify locations of sinkholes in covered karst... more Ground penetrating radar (GPR) is widely used to identify locations of sinkholes in covered karst terrain in Florida. Some sinkholes serve as hydraulic conduits between the surficial and underlying aquifers. Their role is critical in determining the surficial aquifer response to pumping in deeper aquifers. Improved methods for discriminating between hydraulically active sinkholes and plugged sinkholes could help regional water

Research paper thumbnail of Exploring Subglacial Lake Connectivity via Groundwater Aquifers in the Dome C Region, East Antarctica

ABSTRACT Subglacial lakes lying under the Antarctic Ice Sheet form part of a dynamic, interconnec... more ABSTRACT Subglacial lakes lying under the Antarctic Ice Sheet form part of a dynamic, interconnected hydraulic system. Most research exploring the nature of this system has focused on flow along the ice-bed interface, neglecting the effects of groundwater transport, as such systems are thought to lack the transmissivity necessary to accommodate the inferred meltwater volume. In the Dome C region of East Antarctica, however, inferred melt water volumes are relatively low due to proximity to the ice divide and hydraulic gradients are relatively high due to steep subglacial bedrock topography, such that groundwater flow might be viable as a dominant means of water transport. This region contains many small subglacial lakes residing in bedrock depressions of steep basal topography. Preliminary analysis of radar sounding data does not always reveal an obvious hydraulic connection between these lakes despite readily apparent sources of melt feeding these bodies. Here we test several simple models for groundwater flow, including both fractured rock and porous media systems using ice-surface and bedrock geometry inferred from radio-echo sounding data and a published map of melt rates, with the purpose of defining a region in which a groundwater system can account for the majority of the water budget. We then compare these results against maps of basal reflectivity and subglacial lake distribution, as determined from radar sounding data. Areas in which groundwater flow is the dominant process will lack basal lubrication and demonstrate low basal reflectivities, but could still contain small subglacial lakes. While not spatially extensive with respect to the ice sheet, these groundwater-dominated areas could occupy the headwaters of most glacial catchments representing a unique and relatively stable subglacial environment.

Research paper thumbnail of Possible groundwater dominance in the subglacial hydrology of ice sheet interiors: example at Dome C, East Antarctica

The Cryosphere Discussions, 2016

We hypothesize that groundwater systems may be the main water transport mechanism over (distribut... more We hypothesize that groundwater systems may be the main water transport mechanism over (distributed, inefficient) water sheets at large scales in the interiors of ice sheets where melt rates are very low. We compare melt rate magnitudes to potential groundwater volume fluxes and also calculate the theoretical transmissivity ranges of subglacial water sheet and groundwater flow systems. Theoretical groundwater systems are on par with or are more transmissive than water sheets for the upper half of the permeability spectrum. In addition, we develop a 2D cross-sectional subglacial flow path model that connects subglacial lakes near Dome C, East Antarctica. This model integrates subglacial water sheet flux and hypothetical groundwater flow forcing, better bridging two historically disparate modeling frameworks – subglacial hydrology and ice sheet hydrogeology. Our model results suggest that the water sheet thickness can be highly dependent on groundwater flux and that the water sheet tr...