You can do this by implementing a fixed bed. Have a look at Section 1.2.2.7 Bed Material and Fixed Bed Concept of the BASEHPC Reference Manual.

Best regards,
Matthias

Equilibrium transport capacity refers to the transport capacity calculated with the selected bedload formula type (e.g., MPM). What this actually does for the transport_capacity boundary condition in each time step:

1. Calculate the cumulative transport capacity Q_b over the boundary based on the transport capacity in each cell that borders that boundary
2. Calculate a specific transport capacity over the boundary by dividing by the nodestring length q_b = Q_b/L
3. Set the flux at each edge of the boundary to q_b

In this case, the hydraulic state just refers to the flow velocity and depth in the cells along the boundary.

For cases where the transport capacity varies strongly along the nodestring/boundary, this might result in deposition in cells along the boundary where the transport capacity is much smaller than the specific transport capacity q_b. If you want zero sediment transport over the upstream inflow boundary, you can simply not define a upstream boundary condition in the BEDLOAD block.

Best regards,
Matthias

I'm trying to set the fixed bed elevation via a mesh.
The fixed bed mesh has the same topology as the original computational mesh; the only difference is the DTM.
When I write the model.json, I get the following error:

-> out of range (4294967295>=2), in file: Z:\src\setup\Substance.cpp on line 188, version v4.1.0
-> ... unfortunately BASEMENT is killed!

If I remove the FIXED_BED block or if I assign the fixed bed via regions, I do not receive any error messages.

I hope you can download the files from this link

https://drive.google.com/drive/folders/ … drive_link

Thanks

Nicola

Thank you for your support!
Your thesis and example were very helpful.
I was wrong to discretize the grain size distribution.
Now the diameters in the outputs are the same as the grain size curve.

Thank you!

Nicola

This feature is still available for BASEMD  in version 4.0.2, but is currently not implemented for BASEHPC.

Note that version 4.0.2 allows to run both BASEMD and BASEHPC simulations.

Best regards,
Matthias

i am testing the vegetation's module implemented into the latest Basement release and i have any question about it.
 
  > into the "System_Manual_v3-2-0.pdf", page 185, it is specify that "vegetation should be used in combination with a “MPM_like” formula
     for bedload transport..." but into the tutorial file model.json of "Alpine_Rhine_vegetation_tutorial" it is selected only "MPM", which one is
     correct?

  > into the "System_Manual_v3-2-0.pdf", page 147, it is specify that "θcr,v (> θcr,g)" but the "theta_critical_value" used into MPM_like
     formula is 0.047 for bedload and the "veg_theta_critical_fact" is 0.02. So, what is the "veg_theta_critical_fact"?

  > when i set the Strickler value for a vegetation_region into hydraulics module i need to reduce it due to the presence of vegetation or
     should i consider the Strickler value for bare bad and set the correct value into "veg_strickler_fact" ?

Thanks in advance.

Giovanni

as far as I understand by the software and the manual, the "alpha" is referred to as "coefficient", while factor is defined as you define it in your second option.

Please, take a look at the tutorial part in BASEMENT Manual (page 11) and look how the MPM-formula parameters are defined.

Best
Matteo

there is a python tool to extract information from your stringdef. Otherwise you could extract those data using crayfish (QGIS).

Ciao!
Matteo

No, the CURVATURE block is not necessary for modelling bank erosion in a straight channel. Maybe you could post some results and give more details of the model?

Best
Matthias

Have you tried to run the simulation without the DIRECTION (Ikeda) block?

Hi Matthias,

that totally worked for me!

Cheers,
Matteo

I am having issues with the downstream boundary conditions relative to sediment transport.

I have a braided river, so my boundary is very large at its downstream end. I set multiple strings with equilibrium_out and I set the minimum bed elevetion of the string as reference elevation for each string.

At the very first time step (no water on 90% of the downstream elements) all the elements of the downstream boundary experience erosion.

Should I set another reference level like e.g. the mean?

Cheers,
Matteo

I'd like to add another chapter to the MASS-BALANCE problem story: I am running a morph simulation starting from dry condition (but the problem I am experiencing occurs even with "continue" initial conditions).

If I run the simulation with a very short output time step (e.g. 1 second) I don't get any mass balance problem, while if I use a longer output time step the simulation crashes due to MASS-BALANCE issue. If I switch off the "safe_mode" I get some minor MASS-BALANCE problems at the very beginning, after which I can run my simulation without any problem.

Best,

Matteo

I'm coming back to know if there is a plan to do simulation with multigrain? During the meeting of 2020, it was spoken to do it for the summer. Do you have some news about it?

Cheers,

Quentin

Version 3.x is still in development and does not (yet) provide the same functionality as version 2.8. The current implementation with a fixed reference elevation over the whole nodestring is simple and fast. We will consider upgrading the equilibrium_out boundary condition in a future release.

Best regards
Matthias