Christian Langevin (Former Employee)
Science and Products
Filter Total Items: 71
Creative use of pilot points to address site and regional scale heterogeneity in a variable-density model Creative use of pilot points to address site and regional scale heterogeneity in a variable-density model
Pilot points for parameter estimation were creatively used to address heterogeneity at both the well field and regional scales in a variable-density groundwater flow and solute transport model designed to test multiple hypotheses for upward migration of fresh effluent injected into a highly transmissive saline carbonate aquifer. Two sets of pilot points were used within in multiple model...
Authors
Alyssa M. Dausman, John Doherty, Christian D. Langevin
Application of SEAWAT to select variable-density and viscosity problems Application of SEAWAT to select variable-density and viscosity problems
SEAWAT is a combined version of MODFLOW and MT3DMS, designed to simulate three-dimensional, variable-density, saturated groundwater flow. The most recent version of the SEAWAT program, SEAWAT Version 4 (or SEAWAT_V4), supports equations of state for fluid density and viscosity. In SEAWAT_V4, fluid density can be calculated as a function of one or more MT3DMS species, and optionally...
Authors
Alyssa M. Dausman, Christian D. Langevin, Danny T. Thorne, Michael C. Sukop
Evaluating the effect of Tikhonov regularization schemes on predictions in a variable-density groundwater model Evaluating the effect of Tikhonov regularization schemes on predictions in a variable-density groundwater model
Calibration of highly‐parameterized numerical models typically requires explicit Tikhonovtype regularization to stabilize the inversion process. This regularization can take the form of a preferred parameter values scheme or preferred relations between parameters, such as the preferred equality scheme. The resulting parameter distributions calibrate the model to a user‐defined acceptable...
Authors
Jeremy T. White, Christian D. Langevin, Joseph D. Hughes
Use of time series and harmonic constituents of tidal propagation to enhance estimation of coastal aquifer heterogeneity Use of time series and harmonic constituents of tidal propagation to enhance estimation of coastal aquifer heterogeneity
A synthetic two‐dimensional model of a horizontally and vertically heterogeneous confined coastal aquifer system, based on the Upper Floridan aquifer in south Florida, USA, subjected to constant recharge and a complex tidal signal was used to generate 15‐minute water‐level data at select locations over a 7‐day simulation period. “Observed” water‐level data were generated by adding noise
Authors
Joseph D. Hughes, Jeremy T. White, Christian D. Langevin
Effect of numerical dispersion as a source of structural noise in the calibration of a highly parameterized saltwater intrusion model Effect of numerical dispersion as a source of structural noise in the calibration of a highly parameterized saltwater intrusion model
A model with a small amount of numerical dispersion was used to represent saltwater 7 intrusion in a homogeneous aquifer for a 10-year historical calibration period with one 8 groundwater withdrawal location followed by a 10-year prediction period with two groundwater 9 withdrawal locations. Time-varying groundwater concentrations at arbitrary locations in this low-10 dispersion model...
Authors
Christian D. Langevin, Joseph D. Hughes
Effect of sea-level rise on future coastal groundwater resources in southern Florida, USA Effect of sea-level rise on future coastal groundwater resources in southern Florida, USA
An existing variable‐density groundwater flow and solute transport model, developed for the northern part of Broward County, Florida, was used to predict the effect of sealevel rise on future coastal groundwater resources. Using average annual conditions from 2005, simulations were performed for 100 years into the future using four different rates of sea‐level rise: 0, 24, 48, and 88...
Authors
Christian D. Langevin, Michael R. Zygnerski, Jeremy T. White, Joseph D. Hughes
Science and Products
Filter Total Items: 71
Creative use of pilot points to address site and regional scale heterogeneity in a variable-density model Creative use of pilot points to address site and regional scale heterogeneity in a variable-density model
Pilot points for parameter estimation were creatively used to address heterogeneity at both the well field and regional scales in a variable-density groundwater flow and solute transport model designed to test multiple hypotheses for upward migration of fresh effluent injected into a highly transmissive saline carbonate aquifer. Two sets of pilot points were used within in multiple model...
Authors
Alyssa M. Dausman, John Doherty, Christian D. Langevin
Application of SEAWAT to select variable-density and viscosity problems Application of SEAWAT to select variable-density and viscosity problems
SEAWAT is a combined version of MODFLOW and MT3DMS, designed to simulate three-dimensional, variable-density, saturated groundwater flow. The most recent version of the SEAWAT program, SEAWAT Version 4 (or SEAWAT_V4), supports equations of state for fluid density and viscosity. In SEAWAT_V4, fluid density can be calculated as a function of one or more MT3DMS species, and optionally...
Authors
Alyssa M. Dausman, Christian D. Langevin, Danny T. Thorne, Michael C. Sukop
Evaluating the effect of Tikhonov regularization schemes on predictions in a variable-density groundwater model Evaluating the effect of Tikhonov regularization schemes on predictions in a variable-density groundwater model
Calibration of highly‐parameterized numerical models typically requires explicit Tikhonovtype regularization to stabilize the inversion process. This regularization can take the form of a preferred parameter values scheme or preferred relations between parameters, such as the preferred equality scheme. The resulting parameter distributions calibrate the model to a user‐defined acceptable...
Authors
Jeremy T. White, Christian D. Langevin, Joseph D. Hughes
Use of time series and harmonic constituents of tidal propagation to enhance estimation of coastal aquifer heterogeneity Use of time series and harmonic constituents of tidal propagation to enhance estimation of coastal aquifer heterogeneity
A synthetic two‐dimensional model of a horizontally and vertically heterogeneous confined coastal aquifer system, based on the Upper Floridan aquifer in south Florida, USA, subjected to constant recharge and a complex tidal signal was used to generate 15‐minute water‐level data at select locations over a 7‐day simulation period. “Observed” water‐level data were generated by adding noise
Authors
Joseph D. Hughes, Jeremy T. White, Christian D. Langevin
Effect of numerical dispersion as a source of structural noise in the calibration of a highly parameterized saltwater intrusion model Effect of numerical dispersion as a source of structural noise in the calibration of a highly parameterized saltwater intrusion model
A model with a small amount of numerical dispersion was used to represent saltwater 7 intrusion in a homogeneous aquifer for a 10-year historical calibration period with one 8 groundwater withdrawal location followed by a 10-year prediction period with two groundwater 9 withdrawal locations. Time-varying groundwater concentrations at arbitrary locations in this low-10 dispersion model...
Authors
Christian D. Langevin, Joseph D. Hughes
Effect of sea-level rise on future coastal groundwater resources in southern Florida, USA Effect of sea-level rise on future coastal groundwater resources in southern Florida, USA
An existing variable‐density groundwater flow and solute transport model, developed for the northern part of Broward County, Florida, was used to predict the effect of sealevel rise on future coastal groundwater resources. Using average annual conditions from 2005, simulations were performed for 100 years into the future using four different rates of sea‐level rise: 0, 24, 48, and 88...
Authors
Christian D. Langevin, Michael R. Zygnerski, Jeremy T. White, Joseph D. Hughes