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.




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Decay rate in PART program.

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Decay rate in PART program.
coastal model d-particle tracking part
Answer (Unmark)
10/25/14 7:33 AM
Hello all,

Using PART program (Delft3D ver. 4.01), I am simulating larval dispersal of reef fish.
In the model, I used some decay rates [0, 0.10, 0.20, 0.30, 0.40 (1/day)] as larval mortality to see its effect on particle (larval) retention within a study site after pelagic larval duration (8 days).
I expected the particle retention decrease with increasing decay rates, because total number of remaining particles must decrease with increasing decay rates.
However, there was no such a trend in simulation results of particle tracking.

So, I checked number of remaining particles on 1 day after release for each decay rate, but the number did not decrease with decay rates.

Following PART manual, I set decay rates at PROCESS PARAMETERS window when making an input file.
I want to know why decay rates does not affect number of particles in this setting. Any suggestions or answers would be appreciated for it.

Best regards,

Masaaki Sato
RE: Decay rate in PART program.
Answer (Unmark)
10/27/14 7:17 AMas a reply to Masaaki Sato.
Dear Masaaki,

The decay rate does not affect the number of particles in your system, but the mass of each individual particle. A lower mass per particle should lead to lower concentrations.

best regards,
RE: Decay rate in PART program.
Answer (Unmark)
2/2/15 2:27 AMas a reply to Michelle Jeuken.
Dear Michel,

Thank you for reply.
I understood the meaning of decay rate.

Best regards,

RE: Decay rate in PART program.
Answer (Unmark)
4/13/17 4:08 AMas a reply to Masaaki Sato.
Hi Masaaki,

I find this strange too.

I did a test on decay rate in DELFT3D-FLOW and they use first order decay rate, just like how PART defined decay rate in their manual. However, when running model with a expected decay rate of 10% per day (which is 0.105/day), my oil particles decayed almost instantly.

Can anyone help us with this? Thanks.
RE: Decay rate in PART program.
Answer (Unmark)
4/13/17 12:18 PMas a reply to Jack Teo.
Are you sure the oil that this is cause by the decay? It could also be that the oil is dispersed in the water column. you could inspect the <oilname>.csv file for this. Also the out-file should tell you more about why your oil disappears.