intro story DELWAQ


DELWAQ is the engine of the D-Water Quality and D-Ecology programmes of the Delft3D suite. It is based on a rich library from which relevant substances and processes can be selected to quickly put water and sediment quality models together.

The processes library covers many aspects of water quality and ecology, from basic tracers, dissolved oxygen, nutrients, organic matter, inorganic suspended matter, heavy metals, bacteria and organic micro-pollutants, to complex algae and macrophyte dynamics. High performance solvers enable the simulation of long periods, often required to capture the full cycles of the processes being modelled.

The finite volume approach underlying DELWAQ allows it to be coupled to both the structured grid hydrodynamics of the current Delft3D-FLOW engine and the upcoming D-Flow Flexible Mesh engine (1D-2D-3D) of the Delft3D Flexible Mesh Suite (or even other models such as TELEMAC).

'DELWAQ in open source' is our invitation to all leading experts to collaborate in further development and research in the field of water quality, ecology and morphology using Delft3D. Feel free to post your DELWAQ related questions or comments in this dedicated forum space. If you are new to DELWAQ, the tutorial (in the user manual) is a good place to start. A list of DELWAQ related publications is available here.




Sub groups
D-Flow Flexible Mesh

Cohesive sediments & muddy systems


Message Boards

Flow & Wave run COM file coupling error

Clinton Chrystal, modified 7 Years ago.

Flow & Wave run COM file coupling error

Youngling Posts: 7 Join Date: 11/26/12 Recent Posts
Hi everyone, trust you well.
I hope this is just a newbie error that is simple to sort out.

I have successfully run some Delwaq simulations, and the process seems fine when I generate the COM file in the flow output, with flow as a driven only.
But as soon as I run Flow & Waves, my COM file start and stop times are equal, with a zero time step, thus giving me nothing to couple for Delwaq.
If i switch off the waves, then the COM file is fine, with the start and stop time matching the simulation period, and the time step as specified.

Is this a general problem? I would appreciate any assistance in the regard.
Many thanks in advance.
Kind regards,
Arjen Luijendijk, modified 7 Years ago.

RE: Flow & Wave run COM file coupling error

Padawan Posts: 38 Join Date: 2/22/11 Recent Posts
Hi Clint,
Good to hear from you!
I'm not sure that i fully understand your question, but in the FLOW GUI you can prescribe the start and stop time for the com-file even when you have activated the coupling with WAQ (by activating the 'Online coupling' under Output. So simply adjust the times manually. Let us know whether this works or when your problem is more complex.

Cheers, Arjen
Clinton Chrystal, modified 7 Years ago.

RE: Flow & Wave run COM file coupling error (Answer)

Youngling Posts: 7 Join Date: 11/26/12 Recent Posts
Hi Arjen,
man I'd give you a hug if we were in the same room. emoticon

Turns our your suggestion was spot on. Not sure why the post-run coupling was not working with the Waves included,
but I ran a small test case with FLow and Waves, and the online coupling files was produced with the correct time periods for DelWaq to load.
I've started a longer simulation, but it appears to be working.

Thanks so much for the speedy repsonce.
Have a great day!
Cheers, Clint
Amelia Araujo, modified 3 Years ago.

RE: Flow & Wave run COM file coupling error

Youngling Posts: 13 Join Date: 7/7/15 Recent Posts
Hi Arjen,

I am using the waves for the first time in my hydrodynamic model together with tides, and got exactly the same issues as Clint when trying to do the coupling for Delwaq. In your reply you suggest to use "online coupling". Where can I find that field? In the .mdf file, Outputs, I can only see "online visualisation". Do you mean that? It does not make sense to me.


Michel Jeuken, modified 3 Years ago.

RE: Flow & Wave run COM file coupling error

Jedi Knight Posts: 154 Join Date: 1/21/13 Recent Posts

It used to be called 'online coupling', but that was confusing, since water quality it self isn't coupled online, and the direct writing of WAQ input is not 'online', but fully integrated in the code of FLOW. So in newer versions of the FLOW user interface, on the last Output tab is is called Export WAQ Output.