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.

** PLEASE TAG YOUR POST! **

 

 

Sub groups
D-Flow Flexible Mesh
DELWAQ

Cohesive sediments & muddy systems

 


« Back to DELWAQ

Boundary effect

Combination View Flat View Tree View
Threads [ Previous | Next ]
toggle
Boundary effect
Answer (Unmark)
10/7/16 8:19 AM
Hi there,

I've been using Delft3D to run water quality modelling. I've been playing with the input at the boundaries and notice that the loading at the boundary tend to be lower than my input. For example, I have put 5000000 g/m3 at my boundary but the value seem to drop to approximately 12 g/m3 overtime at the boundary area. I would like to understand the mechanisms or boundary effect within the water quality model simulation. Can anyone help?
RE: Boundary effect
Answer (Unmark)
10/7/16 9:39 AMas a reply to S L.
This might happen if the flow at the boundary is outward - then the substance would enter the model area only through dispersion _against_ the flow.

What kind of water system are you modelling? Can you check that the flow is indeed pointing out of the model area?
RE: Boundary effect
Answer (Unmark)
10/9/16 1:16 PMas a reply to Arjen Markus.
Hi Arjen,

Thanks for your response. I'm actually modelling a coastal system with inputs from a few rivers. To be more exactly it is a strait/channel that opens up to the sea on one side and blocked by a causeway on the other side. The flow is pointing into the model area. Would the force or magnitude of the flow influence the boundary discharge?

Thanks in advance.
RE: Boundary effect
Answer (Unmark)
10/10/16 11:53 AMas a reply to S L.
The flow rate will most definitely influence the amount of substance that enters the model area, but we are talking about differences of several orders of magnitude. So the flow rate seems to be very small wrt the ambient flow in the main part of the model. What you could do is put a monitoring point or a monitoring area around the inflows and turn on the mass balance output. This ought to help identifying the problem.

Be sure to use "continuity"| as one of the substances, as that helps with visualising the flows.