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

calculating FRACTIONS in delft3d/delwaq

James Bishop, modified 4 Years ago.

calculating FRACTIONS in delft3d/delwaq


I am trying to figure out how to calculate fractions in DELWAQ . I'm running Delft3D version 4.01.00, 10 layer model. In the D-Water Quality user manual there are instructions for calculating fractions in SOBEK, though nor Delft3D. I see two fractions options available in the Delft3D processes library, 1) fraction freshwater from constant discharge 2) fraction freshwater from variable discharge. How do I implement the fractions simulation? There are no units associated with the fractions substance. Am I to assign some arbitrary value for the fractions and treat it like a concentration? Or is it simply a matter of turning on the fraction simulation (by entering either a 1 or 0)?

The model has multiple sources of fresh inflow and a single source of saline inflow. The fresh and saline flows are boundary conditions and have variable discharge rates.

Michel Jeuken, modified 4 Years ago.

RE: calculating FRACTIONS in delft3d/delwaq (Answer)

Jedi Knight Posts: 154 Join Date: 1/21/13 Recent Posts
We have automatic fraction implemented for Delft3D Fm, but not yet for the structured FLOW. We are working on a connection between the structured FLOW en the new Water Quality user interface.

For the moment, for Delft3D 4.01.00, you can make a tracer file using the processes button, and under tracer and temperature select up to 5 tracers. But since no processes are involved, you could also use your own names in the sub-file if you edit it with a text editor your self. The format is quite simple I think (example attached).

The tric is then you use one of the stracers for initinial, and give an initial concentration of 1 for only this tracer, and then use one tracer for each source that you have, and give only a concentration of 1 for this tracer at this source, and zero for the others. Then you should have a fraction calcualtion, en the sum of al fractions -should- always be 1.


James Bishop, modified 4 Years ago.

RE: calculating FRACTIONS in delft3d/delwaq

Thanks Michel your suggestion worked great!