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

ERROR in GMRES 1 - waq simulations

José Rafael Cavalcanti, modified 1 Year ago.

ERROR in GMRES 1 - waq simulations

Youngling Posts: 6 Join Date: 10/21/18 Recent Posts
I am having problems with my waq simulations. The solver does not reach convergence and I can't understand why. Checking my monitoring file it does not show any NaN in the monitoring points nor any wrong mass balance due to boundary conditions. I am reducing the time step, reaching 30s already but nothing is changing. Is there anything else I can look for in order to solve this problem?
I am simulating a reservoir for a rather short time span (2.5 years). The reservoir has a water level drop of around 8 meters and it returns to the maximum water level by the end of the simulation. The error occur at the end of the first year, where there is no relevant wet- and dry-ing of computational cells taking place. At this point in the simulation, the water levels are already down to the maximum depth but it only rises after 1.5 years and keep rising untill the simulation end. To be more efficient a brief summary of the simulation is:
- Z-layer grid;
- Hydrodynamics for waq generated using the built-in option in FLOW considering a 6hrs time step. I was using 1 day time step to write the results but the problem remained;
- Integration method: 15;
- Time step in waq 30s;
- Zthreshould 0.01 m;
- Emersion option set to 1 in .inp, but if set to 0 does not change the outcome;
Does anyone has a clue where I can start searching for problems?
Gholamreza Shiravani, modified 1 Year ago.

RE: ERROR in GMRES 1 - waq simulations

Padawan Posts: 65 Join Date: 6/25/16 Recent Posts
Hi Josa,
the answer is changing the Parameters related to Dispersion in Input file. Try to reduce them and run again. I hope it works.