Model:TopoFlow-Infiltration-Richards 1D: Difference between revisions

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{{Model identity
|Model type=Single
}}
{{Start models incorporated}}
{{End a table}}
{{Model identity2
|ModelDomain=Hydrology
|Spatial dimensions=2D
|Spatialscale=Landscape-Scale, Watershed-Scale
|One-line model description=Infiltration process component (Richards 1D method) for a D8-based, spatial hydrologic model
|Extended model description=This process component is part of a spatially-distributed hydrologic model called TopoFlow, but it can now be used as a stand-alone model.
}}
{{Start model keyword table}}
{{Model keywords
|Model keywords=basins
}}
{{End a table}}
{{Modeler information
{{Modeler information
|First name=Scott
|First name=Scott
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|Town / City=Boulder
|Town / City=Boulder
|Postal code=80305
|Postal code=80305
|Country=United States
|State=Colorado
|State=Colorado
|Country=USA
|Email address=Scott.Peckham@colorado.edu
|Email address=Scott.Peckham@colorado.edu
|Phone=303-492-6752
|Phone=303-492-6752
|/_10000)λ=residual water content (unitless)
K = Ks * Θeη/λ = hydraulic conductivity (m / s) (see Notes below)
ψ = ψB (Θe-c/λ - 1)1/c - ψA    = pressure head (meters) (see Notes below)
These equations are used to compute the time evolution of 1D (vertical, subsurface) profiles for (1) soil moisture, θ, (2) pressure head, ψ, (3) hydraulic conductivity, K and (4) vertical flow rate, v. TopoFlow solves these equations separately to get time-evolving profiles for every grid cell in a DEM. The result is a 3D grid for each of these four variables that spans the unsaturated zone. The third equation above just defines a variable that is used in the 4th and 5th equations, so the coupled set constitutes 4 equations to be solved for 4 unknowns. These equations can be combined into one nonlinear, parabolic, second-order PDE (partial differential equation) known as the one-dimensional Richards' equation.
}}
{{Model identity
|Model type=Single
|Categories=Hydrology
|Spatial dimensions=2D
|Spatialscale=Landscape-Scale, Watershed-Scale
|One-line model description=Infiltration process component (Richards 1D method) for a D8-based, spatial hydrologic model
|Extended model description=This process component is part of a spatially-distributed hydrologic model called TopoFlow, but it can now be used as a stand-alone model.
|/_10000)λ=residual water content (unitless)
K = Ks * Θeη/λ = hydraulic conductivity (m / s) (see Notes below)
ψ = ψB (Θe-c/λ - 1)1/c - ψA    = pressure head (meters) (see Notes below)
These equations are used to compute the time evolution of 1D (vertical, subsurface) profiles for (1) soil moisture, θ, (2) pressure head, ψ, (3) hydraulic conductivity, K and (4) vertical flow rate, v. TopoFlow solves these equations separately to get time-evolving profiles for every grid cell in a DEM. The result is a 3D grid for each of these four variables that spans the unsaturated zone. The third equation above just defines a variable that is used in the 4th and 5th equations, so the coupled set constitutes 4 equations to be solved for 4 unknowns. These equations can be combined into one nonlinear, parabolic, second-order PDE (partial differential equation) known as the one-dimensional Richards' equation.
}}
}}
{{Model technical information
{{Model technical information
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|Start year development=2001
|Start year development=2001
|Does model development still take place?=Yes
|Does model development still take place?=Yes
|DevelopmentCode=Active
|DevelopmentCodeYearChecked=2020
|Model availability=As code, As teaching tool
|Model availability=As code, As teaching tool
|Source code availability=Through CSDMS repository
|Source code availability=Through web repository
|Source web address=https://github.com/peckhams/topoflow
|Program license type=Apache public license
|Program license type=Apache public license
|OpenMI compliant=No but planned
|CCA component=Yes
|IRF interface=Yes
|Memory requirements=Standard
|Memory requirements=Standard
|Typical run time=Minutes to hours
|Typical run time=Minutes to hours
|/_10000)λ=residual water content (unitless)
K = Ks * Θeη/λ = hydraulic conductivity (m / s) (see Notes below)
ψ = ψB (Θe-c/λ - 1)1/c - ψA    = pressure head (meters) (see Notes below)
These equations are used to compute the time evolution of 1D (vertical, subsurface) profiles for (1) soil moisture, θ, (2) pressure head, ψ, (3) hydraulic conductivity, K and (4) vertical flow rate, v. TopoFlow solves these equations separately to get time-evolving profiles for every grid cell in a DEM. The result is a 3D grid for each of these four variables that spans the unsaturated zone. The third equation above just defines a variable that is used in the 4th and 5th equations, so the coupled set constitutes 4 equations to be solved for 4 unknowns. These equations can be combined into one nonlinear, parabolic, second-order PDE (partial differential equation) known as the one-dimensional Richards' equation.
}}
}}
{{Input - Output description
{{Input - Output description
|Describe input parameters=The input variables used for modeling infiltration and unsaturated vertical flow with the 1D Richard's equation are defined as follows:
|Describe input parameters=The input variables used for modeling infiltration and unsaturated vertical flow with the 1D Richard's equation are defined as follows:
  Ks = saturated hydraulic conductivity (m / s)
  K_s = saturated hydraulic conductivity (m / s)
  Ki = initial hydraulic conductivity (m / s) (typically much less than Ks)
  K_i = initial hydraulic conductivity (m / s) (typically much less than K_s)
  θs = soil water content at ψ = 0 (unitless) (often set to the soil porosity, φ)
  θ_s = soil water content at ψ = 0 (unitless) (often set to the soil porosity, φ)
  θi = initial soil water content (unitless)
  θ_i = initial soil water content (unitless)
  θr = residual soil water content (unitless) (must be < θi)
  θ_r = residual soil water content (unitless) (must be < θ_i)
  ψB = bubbling pressure head (meters) (also called air-entry pressure, ψae)
  ψ_B = bubbling pressure head (meters) (also called air-entry pressure, ψ_ae)
  ψA = pressure head offset parameter (meters)
  ψ_A = pressure head offset parameter (meters)
  λ = pore-size distribution parameter (unitless) (alt. notation = 1/b )
  λ = pore-size distribution parameter (unitless) (alt. notation = 1/b )
  η = 2 + (3 * λ) (unitless) (see Notes)
  η = 2 + (3 * λ) (unitless) (see Notes)
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  nnodes  = number of subsurface vertical nodes  
  nnodes  = number of subsurface vertical nodes  


The behavior of this component is controlled with a configuration (CFG) file, which may point to other files that contain input data. Here is a sample  configuration (CFG) file for this component:
The behavior of this component is controlled with a configuration (CFG) file, which may point to other files that contain input data.
Method code:            4                                                 
Method name:            Richards_1D                                         
Number of layers:      3                                                   
Time step:              Scalar        60.0                    (sec)       
Ks:                    Scalar        7.20000010915e-06      (m/s)       
Ki:                    Scalar        9.84968936528e-08      (m/s)       
qs:                    Scalar        0.485                  (none)       
qi:                    Scalar        0.375807627781          (none)       
qr:                    Scalar        0.0815254493977        (none)       
pB:                    Scalar        -0.785999984741        (m)         
pA:                    Scalar        0.0                    (m)         
lambda:                Scalar        0.188679238493          (none)       
c:                      Scalar        1.0                    (none)       
dz:                    Scalar        0.03                    (m)         
nz:                    Scalar        20                      (none)       
Closest soil_type:      silt_loam                                           
Ks:                    Scalar        6.94999995176e-06      (m/s)       
Ki:                    Scalar        3.29297097399e-08      (m/s)       
qs:                    Scalar        0.451                  (none)       
qi:                    Scalar        0.328764135306          (none)       
qr:                    Scalar        0.071217406467          (none)       
pB:                    Scalar        -0.477999992371        (m)         
pA:                    Scalar        0.0                    (m)         
lambda:                Scalar        0.185528761553          (none)       
c:                      Scalar        1.0                    (none)       
dz:                    Scalar        0.03                    (m)         
nz:                    Scalar        20                      (none)       
Closest soil_type:      loam                                               
Ks:                    Scalar        2.45000002906e-06      (m/s)       
Ki:                    Scalar        3.11491927151e-08      (m/s)       
qs:                    Scalar        0.476                  (none)       
qi:                    Scalar        0.412771789613          (none)       
qr:                    Scalar        0.15295787535          (none)       
pB:                    Scalar        -0.63                  (m)         
pA:                    Scalar        0.0                    (m)         
lambda:                Scalar        0.117370885713          (none)       
c:                      Scalar        1.0                    (none)       
dz:                    Scalar        0.03                    (m)         
nz:                    Scalar        20                      (none)       
Closest soil_type:      clay_loam                                           
Save grid timestep:    Scalar        60.00000000            (sec)
Save v0 grids:          0              Case5_2D-v0.rts        (m/s)
Save q0 grids:          0              Case5_2D-q0.rts        (none)
Save I  grids:          0              Case5_2D-I.rts          (m)
Save Zw grids:          0              Case5_2D-Zw.rts        (m)
Save pixels timestep:  Scalar        60.00000000            (sec)
Save v0 pixels:        0              Case5_0D-v0.txt        (m/s)
Save q0 pixels:        0              Case5_0D-q0.txt        (none)
Save I  pixels:        0              Case5_0D-I.txt          (m)
Save Zw pixels:        0              Case5_0D-Zw.txt        (m)
Save stack timestep:    Scalar        60.00000000            (sec)
Save q stacks:          0              Case5_3D-q.rt3          (none)
Save p stacks:          0              Case5_3D-p.rt3          (m)
Save K stacks:          0              Case5_3D-K.rt3          (m/s)
Save v stacks:          0              Case5_3D-v.rt3          (m/s)
Save profile timestep:  Scalar        60.00000000            (sec)
Save q profiles:        0              Case5_1D-q.txt          (none)
Save p profiles:        0              Case5_1D_p.txt          (m)
Save K profiles:        0              Case5_1D_K.txt          (m/s)
Save v profiles:        0              Case5_1D_v.txt          (m/s)
|Input format=ASCII, Binary
|Input format=ASCII, Binary
|Output format=ASCII, Binary
|Output format=ASCII, Binary
Line 132: Line 69:
|Visualization software needed?=Yes
|Visualization software needed?=Yes
|Other visualization software=VisIt
|Other visualization software=VisIt
|/_10000)λ=residual water content (unitless)
K = Ks * Θeη/λ = hydraulic conductivity (m / s) (see Notes below)
ψ = ψB (Θe-c/λ - 1)1/c - ψA    = pressure head (meters) (see Notes below)
These equations are used to compute the time evolution of 1D (vertical, subsurface) profiles for (1) soil moisture, θ, (2) pressure head, ψ, (3) hydraulic conductivity, K and (4) vertical flow rate, v. TopoFlow solves these equations separately to get time-evolving profiles for every grid cell in a DEM. The result is a 3D grid for each of these four variables that spans the unsaturated zone. The third equation above just defines a variable that is used in the 4th and 5th equations, so the coupled set constitutes 4 equations to be solved for 4 unknowns. These equations can be combined into one nonlinear, parabolic, second-order PDE (partial differential equation) known as the one-dimensional Richards' equation.
}}
}}
{{Process description model
{{Process description model
|Describe processes represented by the model=The Richards 1D method for modeling infiltration.
|Describe processes represented by the model=The Richards 1D method for modeling infiltration.
|Describe key physical parameters and equations=Equations Used by the 1D Richards' Equation Method
|Describe key physical parameters and equations=Equations Used by the 1D Richards' Equation Method
  v = K * (1 - ψ_z) = Darcy's Law for vertical flow rate (m / s)
  v = K * (1 - ψ_z) = Darcy's Law for vertical flow rate (m / s)
  v_z = J - θ_t = conservation of mass,  with source/sink term J
  v_z = J - θ_t = conservation of mass,  with source/sink term J
  Θ_e = (θ - θ_r) / (θ_s - θ_r) = effective saturation or scaled water content (unitless)
  Θ_e = (θ - θ_r) / (θ_s - θ_r) = effective saturation or scaled water content (unitless)
  θ_r = θ_s ( |ψ_B| / 10000)^λ = residual water content (unitless)
  θ_r = θ_s ( abs(ψ_B) / 10000)^λ = residual water content (unitless)
  K = K_s * Θ_e^η/λ = hydraulic conductivity (m / s) (see Notes below)
  K = K_s * Θ_e^η/λ = hydraulic conductivity (m / s) (see Notes below)
  ψ = ψ_B (Θ_e^-c/λ - 1)^1/c - ψ_A   = pressure head (meters) (see Notes below)  
  ψ = ψ_B (Θ_e^-c/λ - 1)^1/c - ψ_A = pressure head (meters) (see Notes below)
 
These equations are used to compute the time evolution of 1D (vertical, subsurface) profiles for (1) soil moisture, θ, (2) pressure head, ψ, (3) hydraulic conductivity, K and (4) vertical flow rate, v. TopoFlow solves these equations separately to get time-evolving profiles for every grid cell in a DEM. The result is a 3D grid for each of these four variables that spans the unsaturated zone. The third equation above just defines a variable that is used in the 4th and 5th equations, so the coupled set constitutes 4 equations to be solved for 4 unknowns. These equations can be combined into one nonlinear, parabolic, second-order PDE (partial differential equation) known as the one-dimensional Richards' equation.
These equations are used to compute the time evolution of 1D (vertical, subsurface) profiles for (1) soil moisture, θ, (2) pressure head, ψ, (3) hydraulic conductivity, K and (4) vertical flow rate, v. TopoFlow solves these equations separately to get time-evolving profiles for every grid cell in a DEM. The result is a 3D grid for each of these four variables that spans the unsaturated zone. The third equation above just defines a variable that is used in the 4th and 5th equations, so the coupled set constitutes 4 equations to be solved for 4 unknowns. These equations can be combined into one nonlinear, parabolic, second-order PDE (partial differential equation) known as the one-dimensional Richards' equation.
|Describe length scale and resolution constraints=Recommended grid cell size is around 100 meters, but can be parameterized to run with a wide range of grid cell sizes. DEM grid dimensions are typically less than 1000 columns by 1000 rows.
|Describe length scale and resolution constraints=Recommended grid cell size is around 100 meters, but can be parameterized to run with a wide range of grid cell sizes. DEM grid dimensions are typically less than 1000 columns by 1000 rows.
|Describe time scale and resolution constraints=The basic stability condition is: dt < (dx / u_min), where dt is the timestep, dx is the grid cell size and u_min is the smallest velocity in the grid.  This ensures that flow cannot cross a grid cell in less than one time step. Typical timesteps are on the order of seconds to minutes. Model can be run for a full year or longer, if necessary.
|Describe time scale and resolution constraints=The basic stability condition is: dt < (dx / u_min), where dt is the timestep, dx is the grid cell size and u_min is the smallest velocity in the grid.  This ensures that flow cannot cross a grid cell in less than one time step. Typical timesteps are on the order of seconds to minutes. Model can be run for a full year or longer, if necessary.
|Describe any numerical limitations and issues=This model/component needs more rigorous testing.
|Describe any numerical limitations and issues=This model/component needs more rigorous testing.
|/_10000)λ=residual water content (unitless)
K = Ks * Θeη/λ = hydraulic conductivity (m / s) (see Notes below)
ψ = ψB (Θe-c/λ - 1)1/c - ψA    = pressure head (meters) (see Notes below)
These equations are used to compute the time evolution of 1D (vertical, subsurface) profiles for (1) soil moisture, θ, (2) pressure head, ψ, (3) hydraulic conductivity, K and (4) vertical flow rate, v. TopoFlow solves these equations separately to get time-evolving profiles for every grid cell in a DEM. The result is a 3D grid for each of these four variables that spans the unsaturated zone. The third equation above just defines a variable that is used in the 4th and 5th equations, so the coupled set constitutes 4 equations to be solved for 4 unknowns. These equations can be combined into one nonlinear, parabolic, second-order PDE (partial differential equation) known as the one-dimensional Richards' equation.
}}
}}
{{Model testing
{{Model testing
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*See /data/progs/topoflow/3.0/data on CSDMS cluster.
*See /data/progs/topoflow/3.0/data on CSDMS cluster.
|Describe ideal data for testing=Several test datasets are stored on the CSDMS cluster at: /data/progs/topoflow/3.0/data.
|Describe ideal data for testing=Several test datasets are stored on the CSDMS cluster at: /data/progs/topoflow/3.0/data.
|/_10000)λ=residual water content (unitless)
K = Ks * Θeη/λ = hydraulic conductivity (m / s) (see Notes below)
ψ = ψB (Θe-c/λ - 1)1/c - ψA    = pressure head (meters) (see Notes below)
These equations are used to compute the time evolution of 1D (vertical, subsurface) profiles for (1) soil moisture, θ, (2) pressure head, ψ, (3) hydraulic conductivity, K and (4) vertical flow rate, v. TopoFlow solves these equations separately to get time-evolving profiles for every grid cell in a DEM. The result is a 3D grid for each of these four variables that spans the unsaturated zone. The third equation above just defines a variable that is used in the 4th and 5th equations, so the coupled set constitutes 4 equations to be solved for 4 unknowns. These equations can be combined into one nonlinear, parabolic, second-order PDE (partial differential equation) known as the one-dimensional Richards' equation.
}}
}}
{{Users groups model
{{Users groups model
|Do you have current or future plans for collaborating with other researchers?=Collaborators include: Larry Hinzman (UAF), Bob Bolton, Anna Liljedahl (UAF), Stefan Pohl and others
|Do you have current or future plans for collaborating with other researchers?=Collaborators include: Larry Hinzman (UAF), Bob Bolton, Anna Liljedahl (UAF), Stefan Pohl and others
|/_10000)λ=residual water content (unitless)
K = Ks * Θeη/λ = hydraulic conductivity (m / s) (see Notes below)
ψ = ψB (Θe-c/λ - 1)1/c - ψA    = pressure head (meters) (see Notes below)
These equations are used to compute the time evolution of 1D (vertical, subsurface) profiles for (1) soil moisture, θ, (2) pressure head, ψ, (3) hydraulic conductivity, K and (4) vertical flow rate, v. TopoFlow solves these equations separately to get time-evolving profiles for every grid cell in a DEM. The result is a 3D grid for each of these four variables that spans the unsaturated zone. The third equation above just defines a variable that is used in the 4th and 5th equations, so the coupled set constitutes 4 equations to be solved for 4 unknowns. These equations can be combined into one nonlinear, parabolic, second-order PDE (partial differential equation) known as the one-dimensional Richards' equation.
}}
}}
{{Documentation model
{{Documentation model
|Provide key papers on model if any=Peckham, S.D. (2008) Geomorphometry and spatial hydrologic modeling (Chapter 22), In: Hengl, T. and Reuter, H.I. (Eds), Geomorphometry: Concepts, Software and Applications. Developments in Soil Science, vol. 33, Elsevier, 377-393 pp.
|Manual model available=Yes
|Manual model available=Yes
|Model website if any=This site.
|Model website if any=This site.
|/_10000)λ=residual water content (unitless)
K = Ks * Θeη/λ = hydraulic conductivity (m / s) (see Notes below)
ψ = ψB (Θe-c/λ - 1)1/c - ψA    = pressure head (meters) (see Notes below)
These equations are used to compute the time evolution of 1D (vertical, subsurface) profiles for (1) soil moisture, θ, (2) pressure head, ψ, (3) hydraulic conductivity, K and (4) vertical flow rate, v. TopoFlow solves these equations separately to get time-evolving profiles for every grid cell in a DEM. The result is a 3D grid for each of these four variables that spans the unsaturated zone. The third equation above just defines a variable that is used in the 4th and 5th equations, so the coupled set constitutes 4 equations to be solved for 4 unknowns. These equations can be combined into one nonlinear, parabolic, second-order PDE (partial differential equation) known as the one-dimensional Richards' equation.
}}
}}
{{Additional comments model
{{Additional comments model
|Comments=About this component:
|Comments=About this component:
*This component was developed as part of the TopoFlow hydrologic model, which was originally written in IDL and had a point-and-click GUI. For more information on TopoFlow, please goto: http://csdms.colorado.edu/wiki/Model:TopoFlow.
*This component was developed as part of the TopoFlow hydrologic model, which was originally written in IDL and had a point-and-click GUI. For more information on TopoFlow, please goto: https://csdms.colorado.edu/wiki/Model:TopoFlow.
*When used from within the CSDMS Modeling Tool (CMT), this component has "config" button which launches a graphical user interface (GUI) for changing input parameters. The GUI is a tabbed dialog with a Help button at the bottom that displays HTML help in a browser window.
*When used from within the CSDMS Modeling Tool (CMT), this component has "config" button which launches a graphical user interface (GUI) for changing input parameters. The GUI is a tabbed dialog with a Help button at the bottom that displays HTML help in a browser window.
*This component also has a configuration (CFG) file, with a name of the form: <case_prefix>_channels_diff_wave.cfg.  This file can be edited with a text editor.
*This component also has a configuration (CFG) file, with a name of the form: <case_prefix>_channels_diff_wave.cfg.  This file can be edited with a text editor.
*The Numerical Python module (numpy) is used for fast, array-based processing.
*The Numerical Python module (numpy) is used for fast, array-based processing.
*This model has an OpenMI-style interface, similar to OpenMI 2.0.  Part of this interface is inherited from "CSDMS_base.py".
*This model has an OpenMI-style interface, similar to OpenMI 2.0.  Part of this interface is inherited from "CSDMS_base.py".
|/_10000)λ=residual water content (unitless)
K = Ks * Θeη/λ = hydraulic conductivity (m / s) (see Notes below)
ψ = ψB (Θe-c/λ - 1)1/c - ψA    = pressure head (meters) (see Notes below)
These equations are used to compute the time evolution of 1D (vertical, subsurface) profiles for (1) soil moisture, θ, (2) pressure head, ψ, (3) hydraulic conductivity, K and (4) vertical flow rate, v. TopoFlow solves these equations separately to get time-evolving profiles for every grid cell in a DEM. The result is a 3D grid for each of these four variables that spans the unsaturated zone. The third equation above just defines a variable that is used in the 4th and 5th equations, so the coupled set constitutes 4 equations to be solved for 4 unknowns. These equations can be combined into one nonlinear, parabolic, second-order PDE (partial differential equation) known as the one-dimensional Richards' equation.
}}
}}
{{CSDMS staff part
|OpenMI compliant=No but planned
|IRF interface=Yes
|CMT component=Yes
|CCA component=Yes
}}
{{Start coupled table}}
{{CSDMS coupled models
|CanCoupleWith=TopoFlow
}}
{{CSDMS coupled models
|CanCoupleWith=TopoFlow-Meteorology
}}
{{CSDMS coupled models
|CanCoupleWith=TopoFlow-Channels-Diffusive Wave
}}
{{CSDMS coupled models
|CanCoupleWith=TopoFlow-Channels-Dynamic Wave
}}
{{CSDMS coupled models
|CanCoupleWith=TopoFlow-Channels-Kinematic Wave
}}
{{CSDMS coupled models
|CanCoupleWith=TopoFlow-Snowmelt-Degree-Day
}}
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==Introduction==
==Introduction==


== History ==
== History ==


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== Issues ==
== Issues ==


== Help ==
== Help ==
[[Model help:TopoFlow-Infiltration-Richards 1D]]


== Input Files ==
== Input Files ==


== Output Files ==
== Output Files ==
== Download ==
== Source ==

Latest revision as of 10:36, 6 June 2025



TopoFlow-Infiltration-Richards 1D


Metadata

Also known as
Model type Single
Model part of larger framework
Note on status model
Date note status model
Incorporated models or components:
Spatial dimensions 2D
Spatial extent Landscape-Scale, Watershed-Scale
Model domain Hydrology
One-line model description Infiltration process component (Richards 1D method) for a D8-based, spatial hydrologic model
Extended model description This process component is part of a spatially-distributed hydrologic model called TopoFlow, but it can now be used as a stand-alone model.
Keywords:

basins,

Name Scott Peckham
Type of contact Model developer
Institute / Organization CSDMS, INSTAAR, University of Colorado
Postal address 1 1560 30th street
Postal address 2
Town / City Boulder
Postal code 80305
State Colorado
Country United States
Email address Scott.Peckham@colorado.edu
Phone 303-492-6752
Fax


Supported platforms
Unix, Linux, Mac OS, Windows
Other platform
Programming language

Python

Other program language None (but uses NumPy package)
Code optimized Single Processor
Multiple processors implemented
Nr of distributed processors
Nr of shared processors
Start year development 2001
Does model development still take place? Yes
If above answer is no, provide end year model development
Code development status Active
When did you indicate the 'code development status'? 2020
Model availability As code, As teaching tool
Source code availability
(Or provide future intension) 		Through web repository
Source web address https://github.com/peckhams/topoflow
Source csdms web address
Program license type Apache public license
Program license type other
Memory requirements Standard
Typical run time Minutes to hours


Describe input parameters The input variables used for modeling infiltration and unsaturated vertical flow with the 1D Richard's equation are defined as follows: 
K_s 	 = saturated hydraulic conductivity (m / s)
K_i 	 = initial hydraulic conductivity (m / s) (typically much less than K_s)
θ_s 	 = soil water content at ψ = 0 (unitless) (often set to the soil porosity, φ)
θ_i 	 = initial soil water content (unitless)
θ_r 	 = residual soil water content (unitless) (must be < θ_i)
ψ_B 	 = bubbling pressure head (meters) (also called air-entry pressure, ψ_ae)
ψ_A 	 = pressure head offset parameter (meters)
λ 	 = pore-size distribution parameter (unitless) (alt. notation = 1/b )
η 	 = 2 + (3 * λ) (unitless) (see Notes)
c 	 = transitional Brooks-Corey curvature parameter (unitless) (see Notes)
dznodes = vertical distance between nodes (meters)
nnodes  = number of subsurface vertical nodes

The behavior of this component is controlled with a configuration (CFG) file, which may point to other files that contain input data.

Input format ASCII, Binary
Other input format
Describe output parameters
Output format ASCII, Binary
Other output format
Pre-processing software needed? Yes
Describe pre-processing software Another program must be used to create the input grids. This includes a D8 flow grid derived from a DEM for the region to be modeled. The earlier, IDL version of TopoFlow can be used to create some of these.
Post-processing software needed? Yes
Describe post-processing software None, except visualization software. Grid sequences saved in netCDF files can be viewed as animations and saved as movies using VisIt.
Visualization software needed? Yes
If above answer is yes
Other visualization software VisIt


Describe processes represented by the model The Richards 1D method for modeling infiltration.
Describe key physical parameters and equations Equations Used by the 1D Richards' Equation Method 
v 	= K * (1 - ψ_z) = Darcy's Law for vertical flow rate (m / s)
v_z 	= J - θ_t 	= conservation of mass,   with source/sink term J
Θ_e 	= (θ - θ_r) / (θ_s - θ_r) = effective saturation or scaled water content (unitless)
θ_r 	= θ_s ( abs(ψ_B) / 10000)^λ = residual water content (unitless)
K 	= K_s * Θ_e^η/λ = hydraulic conductivity (m / s) (see Notes below)
ψ 	= ψ_B (Θ_e^-c/λ - 1)^1/c - ψ_A 	= pressure head (meters) (see Notes below)

These equations are used to compute the time evolution of 1D (vertical, subsurface) profiles for (1) soil moisture, θ, (2) pressure head, ψ, (3) hydraulic conductivity, K and (4) vertical flow rate, v. TopoFlow solves these equations separately to get time-evolving profiles for every grid cell in a DEM. The result is a 3D grid for each of these four variables that spans the unsaturated zone. The third equation above just defines a variable that is used in the 4th and 5th equations, so the coupled set constitutes 4 equations to be solved for 4 unknowns. These equations can be combined into one nonlinear, parabolic, second-order PDE (partial differential equation) known as the one-dimensional Richards' equation.

Describe length scale and resolution constraints Recommended grid cell size is around 100 meters, but can be parameterized to run with a wide range of grid cell sizes. DEM grid dimensions are typically less than 1000 columns by 1000 rows.
Describe time scale and resolution constraints The basic stability condition is: dt < (dx / u_min), where dt is the timestep, dx is the grid cell size and u_min is the smallest velocity in the grid. This ensures that flow cannot cross a grid cell in less than one time step. Typical timesteps are on the order of seconds to minutes. Model can be run for a full year or longer, if necessary.
Describe any numerical limitations and issues This model/component needs more rigorous testing.


Describe available calibration data sets This model/component is typically not calibrated to fit data, but is run with a best guess or measured value for each input parameter.
Upload calibration data sets if available:
Describe available test data sets Available test data sets:
  • Treynor watershed, in the Nishnabotna River basin, Iowa, USA.
  • (Two large rainfall events.)
  • Small basin in Kentucky.
  • Inclined plane for testing.
  • Arctic watershed data from Larry Hinzman (UAF).
  • See /data/progs/topoflow/3.0/data on CSDMS cluster.
Upload test data sets if available:
Describe ideal data for testing Several test datasets are stored on the CSDMS cluster at: /data/progs/topoflow/3.0/data.


Do you have current or future plans for collaborating with other researchers? Collaborators include: Larry Hinzman (UAF), Bob Bolton, Anna Liljedahl (UAF), Stefan Pohl and others
Is there a manual available? Yes
Upload manual if available:
Model website if any This site.
Model forum / discussion board
Comments About this component:
  • This component was developed as part of the TopoFlow hydrologic model, which was originally written in IDL and had a point-and-click GUI. For more information on TopoFlow, please goto: https://csdms.colorado.edu/wiki/Model:TopoFlow.
  • When used from within the CSDMS Modeling Tool (CMT), this component has "config" button which launches a graphical user interface (GUI) for changing input parameters. The GUI is a tabbed dialog with a Help button at the bottom that displays HTML help in a browser window.
  • This component also has a configuration (CFG) file, with a name of the form: <case_prefix>_channels_diff_wave.cfg. This file can be edited with a text editor.
  • The Numerical Python module (numpy) is used for fast, array-based processing.
  • This model has an OpenMI-style interface, similar to OpenMI 2.0. Part of this interface is inherited from "CSDMS_base.py".


Model info
Authors
Scott Peckham
Source code
Model citations
Nr. of publications: 1
Total citations: 12
h-index: 1
m-quotient: 0.06
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Introduction

History

References



Nr. of publications: 1
Total citations: 12
h-index: 1
m-quotient: 0.06



Featured publication(s)YearModel describedType of ReferenceCitations
Peckham, S.D.; 2009. Chapter 25 Geomorphometry and Spatial Hydrologic Modelling. In: (eds.)Developments in Soil Science.. 579–602.
(View/edit entry)		2009 TopoFlow
TopoFlow-Channels-Diffusive Wave
TopoFlow-Channels-Dynamic Wave
TopoFlow-Channels-Kinematic Wave
TopoFlow-Diversions
TopoFlow-Evaporation-Energy Balance
TopoFlow-Evaporation-Priestley Taylor
TopoFlow-Evaporation-Read File
TopoFlow-Infiltration-Green-Ampt
TopoFlow-Infiltration-Richards 1D
TopoFlow-Infiltration-Smith-Parlange
TopoFlow-Meteorology
TopoFlow-Saturated Zone-Darcy Layers
TopoFlow-Snowmelt-Degree-Day
TopoFlow-Snowmelt-Energy Balance

Model overview

12
See more publications of TopoFlow-Infiltration-Richards 1D


Issues

Help

Model help:TopoFlow-Infiltration-Richards 1D

Input Files

Output Files

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