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About this component:
*This component was … About this component:</br>*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.</br>*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.</br>*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.</br>*The Numerical Python module (numpy) is used for fast, array-based processing.</br>*This model has an OpenMI-style interface, similar to OpenMI 2.0. Part of this interface is inherited from "CSDMS_base.py".his interface is inherited from "CSDMS_base.py". +
Yes +
No but planned +
Single Processor +
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20:01:34, 17 February 2010 +
Collaborators include: Larry Hinzman (UAF), Bob Bolton, Anna Liljedahl (UAF), Stefan Pohl and others +
This model/component is typically not calibrated to fit data, but is run with a best guess or measured value for each input parameter. +
Available test data sets:
*Treynor watersh … Available test data sets:</br>*Treynor watershed, in the Nishnabotna River basin, Iowa, USA.</br>* (Two large rainfall events.)</br>*Small basin in Kentucky.</br>*Inclined plane for testing.</br>*Arctic watershed data from Larry Hinzman (UAF).</br>*See /data/progs/topoflow/3.0/data on CSDMS cluster./progs/topoflow/3.0/data on CSDMS cluster. +
Several test datasets are stored on the CSDMS cluster at: /data/progs/topoflow/3.0/data. +
The input variables used for modeling infi … The input variables used for modeling infiltration and unsaturated vertical flow with the 1D Richard's equation are defined as follows:</br> K_s = saturated hydraulic conductivity (m / s)</br> K_i = initial hydraulic conductivity (m / s) (typically much less than K_s)</br> θ_s = soil water content at ψ = 0 (unitless) (often set to the soil porosity, φ)</br> θ_i = initial soil water content (unitless)</br> θ_r = residual soil water content (unitless) (must be < θ_i)</br> ψ_B = bubbling pressure head (meters) (also called air-entry pressure, ψ_ae)</br> ψ_A = pressure head offset parameter (meters)</br> λ = pore-size distribution parameter (unitless) (alt. notation = 1/b )</br> η = 2 + (3 * λ) (unitless) (see Notes)</br> c = transitional Brooks-Corey curvature parameter (unitless) (see Notes)</br> dznodes = vertical distance between nodes (meters)</br> nnodes = number of subsurface vertical nodes </br></br>The behavior of this component is controlled with a configuration (CFG) file, which may point to other files that contain input data.point to other files that contain input data. +
Equations Used by the 1D Richards' Equatio … Equations Used by the 1D Richards' Equation Method</br> v = K * (1 - ψ_z) = Darcy's Law for vertical flow rate (m / s)</br> v_z = J - θ_t = conservation of mass, with source/sink term J</br> Θ_e = (θ - θ_r) / (θ_s - θ_r) = effective saturation or scaled water content (unitless)</br> θ_r = θ_s ( abs(ψ_B) / 10000)^λ = residual water content (unitless)</br> K = K_s * Θ_e^η/λ = hydraulic conductivity (m / s) (see Notes below)</br> ψ = ψ_B (Θ_e^-c/λ - 1)^1/c - ψ_A = pressure head (meters) (see Notes below)</br>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.as the one-dimensional Richards' equation. +
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. +
This model/component needs more rigorous testing. +
None, except visualization software. Grid sequences saved in netCDF files can be viewed as animations and saved as movies using VisIt. +
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. +
The Richards 1D method for modeling infiltration. +
The basic stability condition is: dt < … 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. run for a full year or longer, if necessary. +
Active +
This process component is part of a spatially-distributed hydrologic model called TopoFlow, but it can now be used as a stand-alone model. +
Scott +
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0.06 +
Standard +
Hydrology +
richards +, method +, infiltration +, component +, model called topoflow +, spatially-distributed hydrologic model +, hydrologic model called +, called topoflow +, process component +, component is part +, spatially-distributed hydrologic +, hydrologic model +, model called +, stand-alone model +, topoflow +, model +, process +, part +, basins + and topoflow-infiltration-richards 1d +
basins +
Single +
This site. +
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16:36:03, 6 June 2025 +
1 +
Infiltration process component (Richards 1D method) for a D8-based, spatial hydrologic model +
1560 30th street +
80305 +
true +
None (but uses NumPy package) +
Apache public license +
Python +
Minutes to hours +
Through web repository +
https://github.com/peckhams/topoflow +
2001 +
Model developer +
