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Lake

Lakes and reservoirs are important resources for communities around the globe. They provide food, drinking and irrigation water and can also offer spots for recreation. Under certain conditions lakes can also represent a threat for local communities, such as flooding or limnic eruptions. The ecological state of shallow lakes may be hampered by suspended sediments due to wind driven currents and waves. In deep lakes, stratification can cause undesirable anoxic conditions in the deeper areas. Understanding these systems is crucial to enable a sound management of these water bodies.

 
Delft3D is the state-of-the-art modelling framework for hydrodynamics, water quality, ecology, waves and morphology.
 
Here, in this space, we share knowledge & experiences, and discuss issues related to modelling of lakes.

 

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D-Flow Flexible Mesh
DELWAQ
Cohesive sediments & muddy systems


 

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Sediment transport modelling and initial conditions with z-model option

RR
Ricardo Roman, modified 3 Years ago.

Sediment transport modelling and initial conditions with z-model option

Youngling Posts: 5 Join Date: 8/2/17 Recent Posts
Hi !

I have read some posts in the forum related to this topic and, of course, in the manual, but I am still confused. I want to model a reservoir which is thermal stratified during the whole year but also I want to perform water quality simulations and sediment transport (no morphology, my interest is about suspended load). I found the z-layer should be the correct way to perform this simulation because of the thermal stratification, but I am not sure if, then, I can use the hydrodinamics results to couple with water quality and, specially, with sediment transport. I have found in many post these options "could be" possible, even if in the manual says not. For example, pag # 576 explains there are restrictions in some funtions which are not allowed when using z-model, like: a) 3D Morphology (on line SED), incl. Roller model, b) Coupled FLOW-WAQ simulations ? c) Fluid Mud, etc.

In other post I found something like this (for example): "Sediment transport is a beta option, Morphology is a research area". So I am not sure what this means.

Specifically my questions are:

a) is it possible to performn a suspended sediment simulation using the z-model?. how can I achieve that?
b) is there some way to create vertical-variable initial conditions of temperature and other substances in z-model? (the manual says (pag. 43): Initial condition file is not yet available for the Z-mode")

I would really appreciate any help.

Tahnk you in advance.

Ricardo RB.
JO
Johana Otero, modified 3 Years ago.

RE: Sediment transport modelling and initial conditions with z-model option (Answer)

Youngling Posts: 4 Join Date: 12/19/17 Recent Posts
Hi Ricardo,

I had your very same situation. I am also working in the modeling of suspended sediment transport in two thermal stratified reservoirs. I even contacted the support of Deltares and they confirmed that sediment transport+z-layers is definitely a beta function, since it has not been validated with detailed measurements. To answer your question a: Yes, it is. I started several simulations with the Z-model and sediment transport. This is not supported from the GUI of FLOW, so you have to go to your mdf.file and introduce (type) the keywords to use the Z-layering. For your question b, I would have to check and try to do it. I hope, that I helped you a little bit.

Cheers,
Johana
RR
Ricardo Roman-Botero, modified 3 Years ago.

RE: Sediment transport modelling and initial conditions with z-model option

Youngling Posts: 5 Join Date: 8/2/17 Recent Posts
Hi Johana,

Thank you very much for your prompt reply. Fortunately, as you said, there is some way trying in z-model the sediment modelling topic. Let me ask you if it is possible you share more information about these keywords in the .mdf file. Perhaps some of your simulations can help me very much or more information that the support of Deltares explained on this topic.

Regards

Ricardo RB
JO
Johana Otero, modified 3 Years ago.

RE: Sediment transport modelling and initial conditions with z-model option

Youngling Posts: 4 Join Date: 12/19/17 Recent Posts
Hi Ricardo,

I meant the keywords, that you would normally introduce through the GUI i.e (see section B.11.1 of the Flow manual).:

Zmodel = #Y#
Zbot = %your Zbot here
Ztop = %your Ztop here

If you want to model sediment transport while using the Z-model, you have to type these words in the mdf.file since the input through the GUI is not supported for this case.

Cheers,
Johana
RR
Ricardo Roman-Botero, modified 3 Years ago.

RE: Sediment transport modelling and initial conditions with z-model option

Youngling Posts: 5 Join Date: 8/2/17 Recent Posts
Hi Johana,

Ok, I see now. I was thinking that you probably meant other keywords for sediment transport. But this information is very useful! I will try it and if I have more questions i will post again.

Tahnk you again for your help.

Cheers,

Ricardo RB
RR
Ricardo Roman-Botero, modified 3 Years ago.

RE: Sediment transport modelling and initial conditions with z-model option

Youngling Posts: 5 Join Date: 8/2/17 Recent Posts
Hi

I just tried the option that Johana gave me and, as she said, it works, the model runs. I to set up the model by using the GUI in sigma layers with sediment (Flow Input). Then I modified the .mdf file with the keywords Zmodel, Zbot and Ztop and, finally, I started the simulation using START in the GUI but without enter to the Flow Input again. There were different MESSAGES in the Flow Report File, but especially this was important:

"WARNING Combination of Z-model and 3D Morphology has not yet been tested"

So, thank you again Johana.

Best

Ricardo RB
WI
wobb IN, modified 7 Months ago.

RE: Sediment transport modelling and initial conditions with z-model option

Youngling Posts: 1 Join Date: 8/20/20 Recent Posts
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