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

Increase WAQ simulation period than Flow?

Amaal Osama Fathy, modified 2 Years ago.

Increase WAQ simulation period than Flow?

Youngling Posts: 8 Join Date: 11/6/18 Recent Posts

If the Flow simulation period is 2 weeks and resulted that it was not enough for the DO and BOD curves in observation points to be stabilized  according to Steer-Philips equation. Do I have to run the Flow model for longer time or just I need to increase the WAQ simulation period - with same Flow simulation period- ?

Also in general, if I increased the WAQ simulation period than the Flow, will the model re-use the flow cycle starting from the first time-step or it will use the last time-step calculations as constant to be governing? knowing that the flow is steady. 



Arjen Markus, modified 2 Years ago.

RE: Increase WAQ simulation period than Flow?

Jedi Knight Posts: 223 Join Date: 1/26/11 Recent Posts

WAQ will reuse the hydrodynamic result cyclically if the WAQ simulation period exceeds the FLOW simulation period. That does mean that you have to be a bit careful about the precise period of the hydrodyamic calculation: the start of the (converted) flow field and the end should be close enough, that is end at the same tidal phase, preferrably highwater. Otherwise there would be a large jump in the water volume from the last time in the flow result to the first time, resulting in a mass error. This is corrected for, but still the smaller the correction, the better.