Summary
Also known as
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Model type
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Single
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Model part of larger framework
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Note on status model
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Date note status model
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Technical specs
Supported platforms
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Unix, Linux, Mac OS, Windows
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Other platform
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Programming language
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Python
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Other program language
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None (but uses NumPy package)
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Code optimized
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Single Processor
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Multiple processors implemented
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Nr of distributed processors
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Nr of shared processors
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Start year development
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2001
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Does model development still take place?
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Yes
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If above answer is no, provide end year model development
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Code development status
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When did you indicate the 'code development status'?
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Model availability
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As code, As teaching tool
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Source code availability (Or provide future intension)
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Through CSDMS repository
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Source web address
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Source csdms web address
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Program license type
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Apache public license
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Program license type other
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Memory requirements
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Standard
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Typical run time
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Minutes to hours
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In/Output
Describe input parameters
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The input variables used by the simple Green-Ampt method for modeling infiltration are defined as follows:
K_s = saturated hydraulic conductivity (m / s)
K_i = initial hydraulic conductivity (m / s) (typically much less than Ks)
θ_s = soil water content at ψ=0 (unitless) (typically set to the porosity, φ)
θ_i = initial soil water content (unitless)
G = capillary length scale (meters)
= integral over all ψ of K(ψ) / K_s
= (almost always between ψ_B and 2*ψ_B)
P = precipitation rate (mm / sec)
M = snowmelt rate (mm / sec)
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:
Method code: 0
Method name: Green_Ampt
Number of layers: 1
Time step: Scalar 60.0000000 (sec)
Ks: Scalar 0.00000720 (m/s)
Ki: Scalar 0.00000010 (m/s)
qs: Scalar 0.48500001 (none)
qi: Scalar 0.37580763 (none)
G: Scalar 0.72400000 (m)
Closest soil_type: silt_loam
Save grid timestep: Scalar 60.00000000 (sec)
Save v0 grids: 0 Case5_2D-v0.rts (m/s)
Save I grids: 0 Case5_2D-I.rts (m)
Save pixels timestep: Scalar 60.00000000 (sec)
Save v0 pixels: 0 Case5_0D-v0.txt (m/s)
Save I pixels: 0 Case5_0D-I.txt (m)
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Input format
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ASCII, Binary
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Other input format
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Describe output parameters
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Output format
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ASCII, Binary
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Other output format
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Pre-processing software needed?
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Yes
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Describe pre-processing software
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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.
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Post-processing software needed?
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Yes
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Describe post-processing software
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None, except visualization software. Grid sequences saved in netCDF files can be viewed as animations and saved as movies using VisIt.
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Visualization software needed?
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Yes
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If above answer is yes
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Other visualization software
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VisIt
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Process
Describe processes represented by the model
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The Green-Ampt method for modeling infiltration.
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Describe key physical parameters and equations
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Equations Used by the Green-Ampt Method
f_c = K_i + ((K_s - K_i) * (F + J) / F) = infiltrability (m / sec) (max infiltration rate)
= K_s + (J / F) * (K_s - K_i) = infiltrability (m / sec) (max infiltration rate)
J = G * (θ_s - θ_i) = a quantity used in previous equation (meters)
v_0 = min((P + M), f_c) = infiltration rate at surface (mm / sec) (K_s < (P + M))
= (P + M) = infiltration rate at surface (mm / sec) (K_s > (P + M))
F = ∫ v_0(t) d_t, (from times 0 to t) = cumulative infiltration depth (meters) (vs. I' in Smith (2002)
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Describe length scale and resolution constraints
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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.
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Describe time scale and resolution constraints
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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.
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Describe any numerical limitations and issues
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This model/component needs more rigorous testing.
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Testing
Describe available calibration data sets
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This model/component is typically not calibrated to fit data, but is run with a best guess or measured value for each input parameter.
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Upload calibration data sets if available:
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Describe available test data sets
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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.
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Upload test data sets if available:
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Describe ideal data for testing
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Several test datasets are stored on the CSDMS cluster at: /data/progs/topoflow/3.0/data.
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Other
Do you have current or future plans for collaborating with other researchers?
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Collaborators include: Larry Hinzman (UAF), Bob Bolton, Anna Liljedahl (UAF), Stefan Pohl and others
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Is there a manual available?
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Yes
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Upload manual if available:
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Model website if any
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This site.
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Model forum / discussion board
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Comments
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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.
- 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".
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Introduction
History
Papers
Issues
Help
Input Files
Output Files
Download
Source |