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
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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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[[Describe input parameters model::These inputs must be provided as grids:
- flow_codes = D8 flow codes (Jenson 1984 convention),
- [NE,E,SE,S,SW,W,NW,N] → [1,2,4,8,16,32,64,128]
- bed_slope = slope of the channel bed or hillslope [m / m]
- Manning_n = Manning roughness parameter [s / m^(1/3)]
- bed_width = bed width for trapezoidal cross-section [m]
- bank_angle = bank angle for trapezoid [deg] (from vertical)
These inputs can be provided as scalars or grids:
- sinuosity = channel sinuosity [m/m] (along-channel / straight length)
- init_depth = initial water depth [m] (See HTML help)
Grids must be saved in binary files with no header. All variables should be stored as 4-byte, floating-point numbers (IEEE standard) except flow codes, which are unsigned, 1-byte integers.
Here is a sample configuration (CFG) file for this component:
*Method code: 2
*Method name: Diffusive_Wave
*Manning flag: 1
*Law of Wall flag: 0
*Time step: Scalar 6.00000000 [sec]
*D8 flow code: Grid Treynor_flow.rtg [none]
*D8 slope: Grid Treynor_slope.rtg [m/m]
*Manning N: Grid Treynor_chan-n.rtg [s/m^(1/3)]
*Bed width: Grid Treynor_chan-w.rtg [m]
*Bank angle: Grid Treynor_chan-a.rtg [deg]
*Init. depth: Scalar 0.00000000 [m]
*Sinuosity: Scalar 1.00000000 [m/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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[[Describe output parameters model::This component computes the following variables, as grids:
discharge, Q, [m^3/s];
flow velocity, u, [m/s];
flow depth, d, [m];
friction factor, f, [none];
free-surface slope, S_free, [m/m].
The user can choose which, if any, of these to save. Each may be saved as a grid sequence, indexed by time, in a netCDF file, at a specified sampling rate. Each may also be saved for a set of "monitored" grid cells, each specified as a (row,column) pair in a file with the name "<case_prefix>_outlets.txt". With this option, computed values are saved in a multi-column text file at a specified sampling rate. Each column in this file corresponds to a time series of values for a particular grid cell. For both options the sampling rate must no smaller than the process timestep.]]
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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 a D8 flow grid from a DEM for the region to be modeled.
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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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Process
| Describe processes represented by the model
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The diffusive wave method for flow routing in the channels of a D8-based river network.
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| Describe key physical parameters and equations
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[[Describe key physical parameters::(Source: TopoFlow HTML Help System)
ΔV(i,t)= Δt * [ R(i,t) Δx Δy - Q(i,t) + Σk Q(k,t) ] = change in water volume [m3], mass conservation
d = {[ w2 + 4 tan(θ) V / L]^1/2 - w } / [2 tan(θ)] = mean water depth in channel segment [m] (if θ > 0)
d = V / [w * L] = mean water depth in channel segment [m] (if θ = 0)
Q = v * Aw = discharge of water [m3 / s]
v = n-1 * Rh^2/3 * S^1/2 = section-averaged velocity [m / s], Manning's formula
v = ( g * Rh * S)1/2 * LN( a * d / z0) / κ = section-averaged velocity [m / s], Law of the Wall
Rh = Aw / Pw = hydraulic radius [m]
Aw = d * [w + (d * tan(θ))] = wetted cross-sectional area of a trapezoid [m2]
Pw = w + [2 * d / cos(θ)] = wetted perimeter of a trapezoid [m]
Vw = d2 * [ L * tan(θ) ] + d * [L * w] = wetted volume of a trapezoidal channel [m]]]
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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 timestp, 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).
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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, Tom Over 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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This component was developed as part of the TopoFlow hydrologic model and is used in CSDMS demonstration projects. For more information, please see the model page for TopoFlow. The Numerical Python module (numpy) is used for fast, array-based processing.
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