Christian Langevin (Former Employee)
Science and Products
Filter Total Items: 71
U.S. Geological Survey Science Support Strategy for Biscayne National Park and Surrounding Areas in Southeastern Florida U.S. Geological Survey Science Support Strategy for Biscayne National Park and Surrounding Areas in Southeastern Florida
The U.S. Geological Survey conducts a wide range of research in and around the Biscayne National Park region of southern Florida. This research encompasses the biologic, ecologic, meteorologic, geologic, and hydrologic components of the system, including water-quality analyses, ground-water modeling, hydrogeologic-data collection, ecologic-habitat evaluations, wetlands characterizations
Authors
Melinda A. Wolfert-Lohmann, Christian D. Langevin, Sonya A. Jones, Chris D. Reich, Georgina L. Wingard, Ilsa B. Kuffner, Kevin J. Cunningham
SEAWAT Version 4: A Computer Program for Simulation of Multi-Species Solute and Heat Transport SEAWAT Version 4: A Computer Program for Simulation of Multi-Species Solute and Heat Transport
The SEAWAT program is a coupled version of MODFLOW and MT3DMS designed to simulate three-dimensional, variable-density, saturated ground-water flow. Flexible equations were added to the program to allow fluid density to be calculated as a function of one or more MT3DMS species. Fluid density may also be calculated as a function of fluid pressure. The effect of fluid viscosity variations...
Authors
Christian D. Langevin, Daniel T. Thorne, Alyssa M. Dausman, Michael C. Sukop, Weixing Guo
Modeling axisymmetric flow and transport Modeling axisymmetric flow and transport
Unmodified versions of common computer programs such as MODFLOW, MT3DMS, and SEAWAT that use Cartesian geometry can accurately simulate axially symmetric ground water flow and solute transport. Axisymmetric flow and transport are simulated by adjusting several input parameters to account for the increase in flow area with radial distance from the injection or extraction well. Logarithmic...
Authors
C.D. Langevin
Utilizing spectral analysis of coastal discharge computed by a numerical model to determine boundary influence Utilizing spectral analysis of coastal discharge computed by a numerical model to determine boundary influence
In the present study, a spectral analysis was applied to field data and a numerical model of southeastern Everglades and northeastern Florida Bay that involved computing and comparing the power spectrum of simulated and measured flows at the primary coastal outflow creek. Four dominant power frequencies, corresponding to the S1, S2, M2, and 01 tidal periods, were apparent in the measured...
Authors
E.D. Swain, C.D. Langevin, J.D. Wang
Application of FTLOADDS to Simulate Flow, Salinity, and Surface-Water Stage in the Southern Everglades, Florida Application of FTLOADDS to Simulate Flow, Salinity, and Surface-Water Stage in the Southern Everglades, Florida
The Comprehensive Everglades Restoration Plan requires numerical modeling to achieve a sufficient understanding of coastal freshwater flows, nutrient sources, and the evaluation of management alternatives to restore the ecosystem of southern Florida. Numerical models include a regional water-management model to represent restoration changes to the hydrology of southern Florida and a...
Authors
John D. Wang, Eric D. Swain, Melinda A. Wolfert, Christian D. Langevin, Dawn E. James, Pamela A. Telis
Effect of tidal fluctuations on contaminant transfer to the ocean Effect of tidal fluctuations on contaminant transfer to the ocean
Variable-density groundwater flow was simulated to examine the effects that tide has on the coastward migration of a contaminant through a freshwater/saltwater interface and toward a coastal ocean boundary. Simulated ocean tides did not significantly affect the total contaminant mass input to the ocean; however, the difference in tidal and non-tidal simulated concentrations could be as...
Authors
I.L. Licata, C.D. Langevin, A.M. Dausman
Simulation of submarine groundwater discharge salinity and temperature variations: Implications for remote detection Simulation of submarine groundwater discharge salinity and temperature variations: Implications for remote detection
A hydrological analysis using a numerical simulation was done to identify the transient response of the salinity and temperature of submarine groundwater discharge (SGD) and utilize the results to guide data collection. Results indicate that the amount of SGD fluctuates depending on the ocean stage and geology, with the greatest amount of SGD delivered at low tide when the aquifer is in...
Authors
A.M. Dausman, C.D. Langevin, M.C. Sukop
Addition of simultaneous heat and solute transport and variable fluid viscosity to SEAWAT Addition of simultaneous heat and solute transport and variable fluid viscosity to SEAWAT
SEAWAT is a finite-difference computer code designed to simulate coupled variable-density ground water flow and solute transport. This paper describes a new version of SEAWAT that adds the ability to simultaneously model energy and solute transport. This is necessary for simulating the transport of heat and salinity in coastal aquifers for example. This work extends the equation of state...
Authors
D. Thorne, C.D. Langevin, M.C. Sukop
Three-dimensional model for multi-component reactive transport with variable density groundwater flow Three-dimensional model for multi-component reactive transport with variable density groundwater flow
PHWAT is a new model that couples a geochemical reaction model (PHREEQC-2) with a density-dependent groundwater flow and solute transport model (SEAWAT) using the split-operator approach. PHWAT was developed to simulate multi-component reactive transport in variable density groundwater flow. Fluid density in PHWAT depends not on only the concentration of a single species as in SEAWAT...
Authors
X. Mao, H. Prommer, D.A. Barry, C.D. Langevin, B. Panteleit, L. Li
Movement of the saltwater interface in the surficial aquifer system in response to hydrologic stresses and water-management practices, Broward County, Florida Movement of the saltwater interface in the surficial aquifer system in response to hydrologic stresses and water-management practices, Broward County, Florida
A study was conducted to evaluate the relation between water-level fluctuations and saltwater intrusion in Broward County, Florida. The objective was achieved through data collection at selected wells in Broward County and through the development of a variable-density ground-water flow model. The numerical model is representative of many locations in Broward County that contain a well...
Authors
Alyssa M. Dausman, Christian D. Langevin
Putting radon to work: identifying coastal ground-water discharge sites Putting radon to work: identifying coastal ground-water discharge sites
No abstract available.
Authors
John Crusius, John F. Bratton, Matt Charette
Assigning boundary conditions to the Southern Inland and Coastal Systems (SICS) model using results from the South Florida Water Management Model (SFWMM) Assigning boundary conditions to the Southern Inland and Coastal Systems (SICS) model using results from the South Florida Water Management Model (SFWMM)
The Comprehensive Everglades Restoration Plan (CERP) requires the testing and evaluation of different water-management scenarios for southern Florida. As part of CERP, the South Florida Water Management District is using its regional hydrologic model, the South Florida Water Management Model (SFWMM), to evaluate different hydrologic scenarios. The SFWMM was designed specifically for the...
Authors
Melinda A. Wolfert, Christian D. Langevin, Eric D. Swain
Science and Products
Filter Total Items: 71
U.S. Geological Survey Science Support Strategy for Biscayne National Park and Surrounding Areas in Southeastern Florida U.S. Geological Survey Science Support Strategy for Biscayne National Park and Surrounding Areas in Southeastern Florida
The U.S. Geological Survey conducts a wide range of research in and around the Biscayne National Park region of southern Florida. This research encompasses the biologic, ecologic, meteorologic, geologic, and hydrologic components of the system, including water-quality analyses, ground-water modeling, hydrogeologic-data collection, ecologic-habitat evaluations, wetlands characterizations
Authors
Melinda A. Wolfert-Lohmann, Christian D. Langevin, Sonya A. Jones, Chris D. Reich, Georgina L. Wingard, Ilsa B. Kuffner, Kevin J. Cunningham
SEAWAT Version 4: A Computer Program for Simulation of Multi-Species Solute and Heat Transport SEAWAT Version 4: A Computer Program for Simulation of Multi-Species Solute and Heat Transport
The SEAWAT program is a coupled version of MODFLOW and MT3DMS designed to simulate three-dimensional, variable-density, saturated ground-water flow. Flexible equations were added to the program to allow fluid density to be calculated as a function of one or more MT3DMS species. Fluid density may also be calculated as a function of fluid pressure. The effect of fluid viscosity variations...
Authors
Christian D. Langevin, Daniel T. Thorne, Alyssa M. Dausman, Michael C. Sukop, Weixing Guo
Modeling axisymmetric flow and transport Modeling axisymmetric flow and transport
Unmodified versions of common computer programs such as MODFLOW, MT3DMS, and SEAWAT that use Cartesian geometry can accurately simulate axially symmetric ground water flow and solute transport. Axisymmetric flow and transport are simulated by adjusting several input parameters to account for the increase in flow area with radial distance from the injection or extraction well. Logarithmic...
Authors
C.D. Langevin
Utilizing spectral analysis of coastal discharge computed by a numerical model to determine boundary influence Utilizing spectral analysis of coastal discharge computed by a numerical model to determine boundary influence
In the present study, a spectral analysis was applied to field data and a numerical model of southeastern Everglades and northeastern Florida Bay that involved computing and comparing the power spectrum of simulated and measured flows at the primary coastal outflow creek. Four dominant power frequencies, corresponding to the S1, S2, M2, and 01 tidal periods, were apparent in the measured...
Authors
E.D. Swain, C.D. Langevin, J.D. Wang
Application of FTLOADDS to Simulate Flow, Salinity, and Surface-Water Stage in the Southern Everglades, Florida Application of FTLOADDS to Simulate Flow, Salinity, and Surface-Water Stage in the Southern Everglades, Florida
The Comprehensive Everglades Restoration Plan requires numerical modeling to achieve a sufficient understanding of coastal freshwater flows, nutrient sources, and the evaluation of management alternatives to restore the ecosystem of southern Florida. Numerical models include a regional water-management model to represent restoration changes to the hydrology of southern Florida and a...
Authors
John D. Wang, Eric D. Swain, Melinda A. Wolfert, Christian D. Langevin, Dawn E. James, Pamela A. Telis
Effect of tidal fluctuations on contaminant transfer to the ocean Effect of tidal fluctuations on contaminant transfer to the ocean
Variable-density groundwater flow was simulated to examine the effects that tide has on the coastward migration of a contaminant through a freshwater/saltwater interface and toward a coastal ocean boundary. Simulated ocean tides did not significantly affect the total contaminant mass input to the ocean; however, the difference in tidal and non-tidal simulated concentrations could be as...
Authors
I.L. Licata, C.D. Langevin, A.M. Dausman
Simulation of submarine groundwater discharge salinity and temperature variations: Implications for remote detection Simulation of submarine groundwater discharge salinity and temperature variations: Implications for remote detection
A hydrological analysis using a numerical simulation was done to identify the transient response of the salinity and temperature of submarine groundwater discharge (SGD) and utilize the results to guide data collection. Results indicate that the amount of SGD fluctuates depending on the ocean stage and geology, with the greatest amount of SGD delivered at low tide when the aquifer is in...
Authors
A.M. Dausman, C.D. Langevin, M.C. Sukop
Addition of simultaneous heat and solute transport and variable fluid viscosity to SEAWAT Addition of simultaneous heat and solute transport and variable fluid viscosity to SEAWAT
SEAWAT is a finite-difference computer code designed to simulate coupled variable-density ground water flow and solute transport. This paper describes a new version of SEAWAT that adds the ability to simultaneously model energy and solute transport. This is necessary for simulating the transport of heat and salinity in coastal aquifers for example. This work extends the equation of state...
Authors
D. Thorne, C.D. Langevin, M.C. Sukop
Three-dimensional model for multi-component reactive transport with variable density groundwater flow Three-dimensional model for multi-component reactive transport with variable density groundwater flow
PHWAT is a new model that couples a geochemical reaction model (PHREEQC-2) with a density-dependent groundwater flow and solute transport model (SEAWAT) using the split-operator approach. PHWAT was developed to simulate multi-component reactive transport in variable density groundwater flow. Fluid density in PHWAT depends not on only the concentration of a single species as in SEAWAT...
Authors
X. Mao, H. Prommer, D.A. Barry, C.D. Langevin, B. Panteleit, L. Li
Movement of the saltwater interface in the surficial aquifer system in response to hydrologic stresses and water-management practices, Broward County, Florida Movement of the saltwater interface in the surficial aquifer system in response to hydrologic stresses and water-management practices, Broward County, Florida
A study was conducted to evaluate the relation between water-level fluctuations and saltwater intrusion in Broward County, Florida. The objective was achieved through data collection at selected wells in Broward County and through the development of a variable-density ground-water flow model. The numerical model is representative of many locations in Broward County that contain a well...
Authors
Alyssa M. Dausman, Christian D. Langevin
Putting radon to work: identifying coastal ground-water discharge sites Putting radon to work: identifying coastal ground-water discharge sites
No abstract available.
Authors
John Crusius, John F. Bratton, Matt Charette
Assigning boundary conditions to the Southern Inland and Coastal Systems (SICS) model using results from the South Florida Water Management Model (SFWMM) Assigning boundary conditions to the Southern Inland and Coastal Systems (SICS) model using results from the South Florida Water Management Model (SFWMM)
The Comprehensive Everglades Restoration Plan (CERP) requires the testing and evaluation of different water-management scenarios for southern Florida. As part of CERP, the South Florida Water Management District is using its regional hydrologic model, the South Florida Water Management Model (SFWMM), to evaluate different hydrologic scenarios. The SFWMM was designed specifically for the...
Authors
Melinda A. Wolfert, Christian D. Langevin, Eric D. Swain