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

Stopped with error code: 1

James Bishop, modified 4 Years ago.

Stopped with error code: 1


I am running a 10 layer DELWAQ simulation with 5 conservative tracers and twice now the simulation terminated ~ 9% into the run with the message - 'Stopped with error code: 1'.

I have reviewed the .lsp and .lst files (attached) and there are no errors indicated. I did have the iteration report turned on and when I view the .mon file (also attached) the last line of the file says - ERROR: NaN in RHS of segment: 732051

Any idea what the problem could be?

I should note that previously I successfully a similar simulation to completion; the only change I made (that I am aware of) is the concentration at one of the boundaries. Could this be causing the error?

Also attached is the input file.

Arjen Markus, modified 4 Years ago.

RE: Stopped with error code: 1

Jedi Knight Posts: 223 Join Date: 1/26/11 Recent Posts
This message indicates that the calculation became unstable - the numbers will then quickly grow towards infinity. NaN means "not a number" - computer speak for saying the result of some calculation (something like x = infinity - infinity or y = 0/0) gave a result that cannot be represented as a (real/floating-point) number.

As to why the calculation would fail if the only change is a boundary condition, that very much depends on the model you are running. It may be that in the successful run the concentrations near that boundary are zero or near zero for a long time, enough to pass over the period that the stability criteria are violated.

I didn't see your input file, but there will be more to it than merely the .inp file ;).