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

Z-layers model, problem with boundary conditions in Delwaq

Marcin Kawka, modified 7 Years ago.

Z-layers model, problem with boundary conditions in Delwaq

I'm trying to model inorganic suspended matter in Delwaq. In sigma-layers model boundary condition works well, however due to lake stratification I would like to use z-model. Delft3d z-layer model of my lake works well with passive tracer so I assume that there is no problem with hydrodynamic part.
In coupling file I have manualy modified the following line:
geometry curvilinear-grid z-layers

In simulation results it looks like there is no influence of the boundary condition. Another strange thing is spatial result (attached picture). I am using 30 layers and in z-layer mode layer no.30 should be the top one, while I see a spatial pattern resembling the shape of the bottom one.

Are there any more changes I should do in simulation files in order to use z-layers instead of sigma-layers?

Marcin Kawka
Anonymous Anonymous, modified 7 Years ago.

RE: Z-layers model, problem with boundary conditions in Delwaq (Answer)

Jedi Master Posts: 333 Join Date: 7/30/20 Recent Posts
Hi Marcin,

This is a known issue. The offline coupling does not work well with z-layers for the moment. You will have to use the built-in coupling instead. See this thread for more info.

Also, Delwaq uses another numbering convention than FLOW (from top to bottom, so layer 1 is the surface layer).

Good luck,