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

Delft Flow-WAQ coupling error

Narayanage Nirmal, modified 3 Years ago.

Delft Flow-WAQ coupling error

Youngling Posts: 1 Join Date: 4/5/17 Recent Posts
need help!!!
I am trying to couple flow and waq modules.

The flow model ran successfully and generated the com- file for the coupling. But, When I try to run the coupling program, I get the following error message. Can anyone suggest what might be wrong in my flow or coupling set up? Thanks

Delft3D-FLOW - Water Quality
Deltares, COUP203 Version, Jan 18 2013, 09:42:45

PC/Windows/Linux version

ERROR: integer expected, but not found ??
are you using the correct input file ??
for input files of => v2.4 use header:

Exit from Delft3D-Coupling

child process exited abnormally
Michelle Jeuken, modified 3 Years ago.

RE: Delft Flow-WAQ coupling error

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

From your message I could only suggest what the message already says: are you using the correct input file ??

Besides that I could strongly advise you to use the online couling program in your flow runs. Switch on Export WAQ input, and use the edit WAQ input button to go to the next screen, and make the correct settings.

Michelle Loozen, modified 2 Years ago.

RE: Delft Flow-WAQ coupling error

Youngling Posts: 2 Join Date: 6/27/18 Recent Posts

Hi all,

Im having the same problem. 

I would like to couple the results from FLOW in the PART tracking module.

However the flow model does not create a 'COM' file and output of Delft3D flow I could not select the 'online coupling' bottom.

What could i do? 


Michelle Jeuken, modified 2 Years ago.

RE: Delft Flow-WAQ coupling error

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

Hi Michelle,

If you couldn't see the 'Export WAQ input' option, or in older FLOW GUI versions, the 'online coupling' at the bottom of the output section, that could only be if you have a very old version of the FLOW GUI (>5 years). Email to delft3d.support@deltares.nl for a newer version of the (oss) GUI.

If you also don't see a com-file, things you could check are the start and stop timers and the interval. When the interval is zero, the com-file will not be produced. The same goes for the preferred 'Export WAQ input' option, that will only produce a hyd-file (that is directly usable by PART) when the timings are correct.




HARRISON an, modified 9 Months ago.

RE: Delft Flow-WAQ coupling error

Youngling Posts: 1 Join Date: 7/17/20 Recent Posts
The Delft flow project is most competent and successful run flow model. But sometime you might face error in running this model. To solve this error you should make some changes in setting for proper working. The https://essay-reviewer.com is one of the competent forum for reviewing your articles.