Model:Bifurcation

Bifurcation

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	1.5D
Spatial extent	Landscape-Scale
Model domain	Coastal
One-line model description	Flow-partitioning and avulsion in a river delta bifurcation
Extended model description	Bifurcation is a morphodynamic model of a river delta bifurcation. Model outputs include flux partitioning and 1D bed elevation profiles, all of which can evolve through time. Interaction between the two branches occurs in the reach just upstream of the bifurcation, due to the development of a transverse bed slope. Aside from this interaction, the individual branches are modeled in 1D. The model generates ongoing avulsion dynamics automatically, arising from the interaction between an upstream positive feedback and the negative feedback from branch progradation and/or aggradation. Depending on the choice of parameters, the model generates symmetry, soft avulsion, or full avulsion. Additionally, the model can include differential subsidence. It can also be run under bypass conditions, simulating the effect of an offshore sink, in which case ongoing avulsion dynamics do not occur. Possible uses of the model include the study of avulsion, bifurcation stability, and the morphodynamic response of bifurcations to external changes.

Keywords:

Supported platforms	Unix, Linux, Mac OS, Windows
Other platform
Programming language	Matlab
Other program language
Code optimized	Single Processor
Multiple processors implemented
Nr of distributed processors
Nr of shared processors
Start year development	2015
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 CSDMS repository
Source web address
Source csdms web address	https://github.com/csdms-contrib/bifurcation
Program license type	GPL v3
Program license type other
Memory requirements
Typical run time	minutes

Describe input parameters	Modify input parameters directly in Matlab script Inputs include initial conditions, upstream flow conditions, bifurcation geometry, bypass fraction, sea level (optional), differential subsidence rate (optional)
Input format
Other input format
Describe output parameters	time series - such as water and sediment partitioning spatial - such as bed elevation profiles, saved at lower time resolution (chosen by user)
Output format
Other output format
Pre-processing software needed?	No
Describe pre-processing software
Post-processing software needed?	No
Describe post-processing software
Visualization software needed?	No
If above answer is yes
Other visualization software

Describe processes represented by the model	quasi-normal flow (1D) downstream and transverse sediment fluxes mass conservation (Exner)
Describe key physical parameters and equations	see publication
Describe length scale and resolution constraints	cell size of the upstream two cells is an intrinsic model parameter, but downstream cell size can be chosen arbitrarily
Describe time scale and resolution constraints	none
Describe any numerical limitations and issues	uses forward-Euler timestepping, therefore timestep must be small enough to insure numerical stability

Describe available calibration data sets
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Describe available test data sets
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Describe ideal data for testing

Do you have current or future plans for collaborating with other researchers?

Is there a manual available?	No
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Model website if any
Model forum / discussion board

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Featured reference(s)	Open Access Status	Year	Type of Reference	Cited
Salter, Gerard; Paola, Chris; Voller, Vaughan R.; 2018. Control of Delta Avulsion by Downstream Sediment Sinks. Journal of Geophysical Research: Earth Surface, 123142–166. 10.1002/2017JF004350	· publishedVersion	2018	a module overview describing a module	45