Model:TopoFlow-Channels-Dynamic Wave

TopoFlow-Channels-Dynamic Wave

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
One-line model description	Dynamic Wave process component for flow routing in 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. The dynamic wave method is the most complete and complex method for modeling flow in open channels. This method retains all of the terms in the full, 1D momentum equation, including the gravity, friction and pressure gradient terms (as used by the diffusive wave method) as well as local and convective acceleration (or momentum flux) terms. This full equation is known as the St. Venant equation. In the current version of TopoFlow it is assumed that the flow directions are static and given by a D8 flow grid. In this case, integral vs. differential forms of the conservation equations for mass and momentum can be used.

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
When did you indicate the 'code development status'?
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 the Dynamic Wave method of routing flow in channels are defined as follows. These inputs must be provided as grids: flow_codes = D8 flow codes (Jenson 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 / m1/3) bed_width = bed width for trapezoidal cross-section (m) bank_angle = bank angle for trapezoid (deg) (from vertical) sinuosity = channel sinuosity (unitless) (along-channel / straight length) init_depth = initial water depth (m) (See Notes below) 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. 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: 3 Method name: Dynamic_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) Save grid timestep: Scalar 60.00000000 (sec) Save Q grids: 1 Case5_2D-Q.rts (m^3/s) Save u grids: 0 Case5_2D-u.rts (m/s) Save d grids: 0 Case5_2D-d.rts (m) Save f grids: 0 Case5_2D-f.rts (none) Save pixels timestep: Scalar 60.00000000 (sec) Save Q pixels: 1 Case5_0D-Q.txt (m^3/s) Save u pixels: 0 Case5_0D-u.txt (m/s) Save d pixels: 0 Case5_0D-d.txt (m) Save f pixels: 0 Case5_0D-f.txt (none)
Input format	ASCII, Binary
Other input format
Describe output parameters	This component computes the following variables, as grids: Q = discharge (m^3/s) u = flow velocity (m/s) d = flow depth (m) f = friction factor (none) Rh = hydraulic radius (m) S_free = free-surface slope (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.
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 dynamic wave method for flow routing in the channels of a D8-based river network.
Describe key physical parameters and equations	Main equations used by this component: ΔV(i,t) = Δt * ( R(i,t) Δx Δy - Q(i,t) + Σ_k Q(k,t) ) = change in water volume (m^3) (mass cons.) d = {( w^2 + 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) Δv(i,t) = Δt * (T_1 + T_2 + T_3 + T_4 + T_5) / ( d(i,t) * A_w )= change in mean velocity (m / s) (mom. cons.) T_1 = v(i,t) * Q(i,t) * (C - 1) = efflux term in equation for Δv T_2 = Σ_k (v(k,t) - v(i,t) * C) * Q(k,t) = influx term in equation for Δv T_3 = -v(i,t) * C * R(i,t) * Δx * Δy = "new mass" momentum term in equation for Δv T_4 = A_w * (g * d(i,t) * S(i,t)) = gravity term in equation for Δv T_5 = -A_w * (f(i,t) * v(i,t)^2) = friction term in equation for Δv Q = v * A_w = discharge of water (m^3 / s) f(i,t) = ( κ / LN ( a * d(i,t) / z_0) )^2 = friction factor (unitless) (for law of the wall) f(i,t) = g * n^2 / Rh(i,t)^1/3 = friction factor (unitless) (for Manning's equation) C = A_w / A_t = area ratio appearing in equation for Δv A_t = w_t * L = top surface area of a channel segment (m2) (L = length) w_t = w + ( 2 * d * tan(θ) ) = top width of a wetted trapezoidal cross-section (m) R_h = A_w / P_w = hydraulic radius (m) A_w = d * (w + (d * tan(θ))) = wetted cross-sectional area of a trapezoid (m2) P_w = w + (2 * d / cos(θ)) = wetted perimeter of a trapezoid (m) V_w = d^2 * ( L * tan(θ) ) + d * (L * w) = wetted volume of a trapezoidal channel (m) (Source: TopoFlow HTML Help System)
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, Tom Over 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: 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".

This part will be filled out by CSDMS staff

OpenMI compliant	No but planned
BMI compliant	Yes
WMT component	Yes
PyMT component
Is this a data component

Can be coupled with:	CanCoupleWith, CanCoupleWith, CanCoupleWith, CanCoupleWith, CanCoupleWith, CanCoupleWith, CanCoupleWith, CanCoupleWith, CanCoupleWith, CanCoupleWith, CanCoupleWith, CanCoupleWith, CanCoupleWith,

Model info

Authors

Scott Peckham

Source code

Go to external source code site

Model citations

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

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References

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

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Model_help:TopoFlow-Channels-Dynamic_Wave

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