Christopher T Green, Ph.D.
Christopher Green is a Research Hydrologist with the USGS Water Resources Mission Area.
Research Interests
- Flow and reactive transport in complex geological media
- Nitrogen cycling and fluxes in groundwater in agricultural areas
- Flow and solute transport in the unsaturated zone
- Gas transport in the unsaturated zone
- Effects of biofuels crops on groundwater quality
Science and Products
Filter Total Items: 45
Predicting unsaturated zone nitrogen mass balances in agricultural settings of the United States
Unsaturated zone N fate and transport were evaluated at four sites to identify the predominant pathways of N cycling: an almond [Prunus dulcis (Mill.) D.A. Webb] orchard and cornfield (Zea mays L.) in the lower Merced River study basin, California; and corn–soybean [Glycine max (L.) Merr.] rotations in study basins at Maple Creek, Nebraska, and at Morgan Creek, Maryland. We used inverse modeling w
Authors
Bernard T. Nolan, Larry J. Puckett, Liwang Ma, Christopher T. Green, E. Randall Bayless, Robert W. Malone
Spatial and temporal trends in nitrate concentrations in the eastern San Joaquin Valley regional aquifer and implications for fertilizer management
Ground-water withdrawals in the San Joaquin Valley totaled 64 million m3 /day (19 million ac-ft) in 2000, supplying about 45% of agricultural irrigation demand and about 80% of municipal supply (Hutson et al., 2004). Most of the population and ground-water use are in the eastern San Joaquin Valley, where reliance on ground water is expected to increase as a result of rapid population growth and li
Authors
Karen R. Burow, Christopher T. Green
Nitrogen fluxes through unsaturated zones in five agricultural settings across the United States
The main physical and chemical controls on nitrogen (N) fluxes between the root zone and the water table were determined for agricultural sites in California, Indiana, Maryland, Nebraska, and Washington from 2004 to 2005. Sites included irrigated and nonirrigated fields; soil textures ranging from clay to sand; crops including corn, soybeans, almonds, and pasture; and unsaturated zone thicknesses
Authors
C.T. Green, L.H. Fisher, B.A. Bekins
Limited occurrence of denitrification in four shallow aquifers in agricultural areas of the United States
The ability of natural attenuation to mitigate agricultural nitrate contamination in recharging aquifers was investigated in four important agricultural settings in the United States. The study used laboratory analyses, field measurements, and flow and transport modeling for monitoring well transects (0.5 to 2.5 km in length) in the San Joaquin watershed, California, the Elkhorn watershed, Nebrask
Authors
C.T. Green, L.J. Puckett, J.K. Böhlke, B.A. Bekins, S.P. Phillips, L. J. Kauffman, J. M. Denver, H.M. Johnson
Simulation of Multiscale Ground-Water Flow in Part of the Northeastern San Joaquin Valley, California
The transport and fate of agricultural chemicals in a variety of environmental settings is being evaluated as part of the U.S. Geological Survey (USGS) National Water-Quality Assessment Program. One of the locations being evaluated is a 2,700-km2 (square kilometer) regional study area in the northeastern San Joaquin Valley surrounding the city of Modesto, an area dominated by irrigated agriculture
Authors
Steven P. Phillips, Christopher T. Green, Karen R. Burow, Jennifer L. Shelton, Diane L. Rewis
Multiphase flow in geometrically simple fracture intersections
A two-dimensional lattice Boltzmann (LB) model with fluid-fluid and solid-fluid interaction potentials was used to study gravity-driven flow in geometrically simple fracture intersections. Simulated scenarios included fluid dripping from a fracture aperture, two-phase flow through intersecting fractures and thin-film flow on smooth and undulating solid surfaces. Qualitative comparisons with recent
Authors
H. Basagaoglu, P. Meakin, C.T. Green, M. Mathew
Evaluation of unsaturated-zone solute-transport models for studies of agricultural chemicals
Seven unsaturated-zone solute-transport models were tested with two data sets to select models for use by the Agricultural Chemical Team of the U.S. Geological Survey's National Water-Quality Assessment Program. The data sets were from a bromide tracer test near Merced, California, and an atrazine study in the White River Basin, Indiana. In this study the models are designated either as complex or
Authors
Bernard T. Nolan, E. Randall Bayless, Christopher T. Green, Sheena Garg, Frank D. Voss, David C. Lampe, Jack E. Barbash, Paul D. Capel, Barbara A. Bekins
Percolation and transport in a sandy soil under a natural hydraulic gradient
Unsaturated flow and transport under a natural hydraulic gradient in a Mediterranean climate were investigated with a field tracer experiment combined with laboratory analyses and numerical modeling. Bromide was applied to the surface of a sandy soil during the dry season. During the subsequent rainy season, repeated sediment sampling tracked the movement of bromide through the profile. Analysis o
Authors
Christopher T. Green, David A. Stonestrom, Barbara A. Bekins, Katherine C. Akstin, Marjorie S. Schulz
Lattice-Boltzmann simulation of coalescence-driven island coarsening
The first-order phase separation in a thin fluid film was simulated using a two-dimensional lattice-Boltzman model (LBM) with fluid-fluid interactions. The effects of the domain size on the intermediate asymptotic island size distribution were also discussed. It was observed that the overall process is dominated by coalescence which is independent of island mass. The results show that the combined
Authors
H. Basagaoglu, C.T. Green, P. Meakin, B.J. McCoy
Science and Products
Filter Total Items: 45
Predicting unsaturated zone nitrogen mass balances in agricultural settings of the United States
Unsaturated zone N fate and transport were evaluated at four sites to identify the predominant pathways of N cycling: an almond [Prunus dulcis (Mill.) D.A. Webb] orchard and cornfield (Zea mays L.) in the lower Merced River study basin, California; and corn–soybean [Glycine max (L.) Merr.] rotations in study basins at Maple Creek, Nebraska, and at Morgan Creek, Maryland. We used inverse modeling w
Authors
Bernard T. Nolan, Larry J. Puckett, Liwang Ma, Christopher T. Green, E. Randall Bayless, Robert W. Malone
Spatial and temporal trends in nitrate concentrations in the eastern San Joaquin Valley regional aquifer and implications for fertilizer management
Ground-water withdrawals in the San Joaquin Valley totaled 64 million m3 /day (19 million ac-ft) in 2000, supplying about 45% of agricultural irrigation demand and about 80% of municipal supply (Hutson et al., 2004). Most of the population and ground-water use are in the eastern San Joaquin Valley, where reliance on ground water is expected to increase as a result of rapid population growth and li
Authors
Karen R. Burow, Christopher T. Green
Nitrogen fluxes through unsaturated zones in five agricultural settings across the United States
The main physical and chemical controls on nitrogen (N) fluxes between the root zone and the water table were determined for agricultural sites in California, Indiana, Maryland, Nebraska, and Washington from 2004 to 2005. Sites included irrigated and nonirrigated fields; soil textures ranging from clay to sand; crops including corn, soybeans, almonds, and pasture; and unsaturated zone thicknesses
Authors
C.T. Green, L.H. Fisher, B.A. Bekins
Limited occurrence of denitrification in four shallow aquifers in agricultural areas of the United States
The ability of natural attenuation to mitigate agricultural nitrate contamination in recharging aquifers was investigated in four important agricultural settings in the United States. The study used laboratory analyses, field measurements, and flow and transport modeling for monitoring well transects (0.5 to 2.5 km in length) in the San Joaquin watershed, California, the Elkhorn watershed, Nebrask
Authors
C.T. Green, L.J. Puckett, J.K. Böhlke, B.A. Bekins, S.P. Phillips, L. J. Kauffman, J. M. Denver, H.M. Johnson
Simulation of Multiscale Ground-Water Flow in Part of the Northeastern San Joaquin Valley, California
The transport and fate of agricultural chemicals in a variety of environmental settings is being evaluated as part of the U.S. Geological Survey (USGS) National Water-Quality Assessment Program. One of the locations being evaluated is a 2,700-km2 (square kilometer) regional study area in the northeastern San Joaquin Valley surrounding the city of Modesto, an area dominated by irrigated agriculture
Authors
Steven P. Phillips, Christopher T. Green, Karen R. Burow, Jennifer L. Shelton, Diane L. Rewis
Multiphase flow in geometrically simple fracture intersections
A two-dimensional lattice Boltzmann (LB) model with fluid-fluid and solid-fluid interaction potentials was used to study gravity-driven flow in geometrically simple fracture intersections. Simulated scenarios included fluid dripping from a fracture aperture, two-phase flow through intersecting fractures and thin-film flow on smooth and undulating solid surfaces. Qualitative comparisons with recent
Authors
H. Basagaoglu, P. Meakin, C.T. Green, M. Mathew
Evaluation of unsaturated-zone solute-transport models for studies of agricultural chemicals
Seven unsaturated-zone solute-transport models were tested with two data sets to select models for use by the Agricultural Chemical Team of the U.S. Geological Survey's National Water-Quality Assessment Program. The data sets were from a bromide tracer test near Merced, California, and an atrazine study in the White River Basin, Indiana. In this study the models are designated either as complex or
Authors
Bernard T. Nolan, E. Randall Bayless, Christopher T. Green, Sheena Garg, Frank D. Voss, David C. Lampe, Jack E. Barbash, Paul D. Capel, Barbara A. Bekins
Percolation and transport in a sandy soil under a natural hydraulic gradient
Unsaturated flow and transport under a natural hydraulic gradient in a Mediterranean climate were investigated with a field tracer experiment combined with laboratory analyses and numerical modeling. Bromide was applied to the surface of a sandy soil during the dry season. During the subsequent rainy season, repeated sediment sampling tracked the movement of bromide through the profile. Analysis o
Authors
Christopher T. Green, David A. Stonestrom, Barbara A. Bekins, Katherine C. Akstin, Marjorie S. Schulz
Lattice-Boltzmann simulation of coalescence-driven island coarsening
The first-order phase separation in a thin fluid film was simulated using a two-dimensional lattice-Boltzman model (LBM) with fluid-fluid interactions. The effects of the domain size on the intermediate asymptotic island size distribution were also discussed. It was observed that the overall process is dominated by coalescence which is independent of island mass. The results show that the combined
Authors
H. Basagaoglu, C.T. Green, P. Meakin, B.J. McCoy