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

Algae phenotypes concentration

Fernando Aguilar, modified 5 Years ago.

Algae phenotypes concentration

Youngling Posts: 22 Join Date: 2/7/13 Recent Posts
Hi all,

I am modlling algae bloom using Delft3D suite. I have different types of algae and the model represent them with 3 phenotypes: E, P, N. For initial conditions I use values that comes from concentration data that I convert using biomass. My question is: Should I divide this concentration in 3 (for each phenotype) or should I keep the same value in all?

Thank you,

Anonymous Anonymous, modified 5 Years ago.

RE: Algae phenotypes concentration

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

You don't really need to specify initial algae concentrations when using BLOOM.
BLOOM has hard coded minimum algae masses for each type, which it will use as initial conditions as well. If you specify your own initial conditions, BLOOM will use them if they are larger than it's minimum values.

As for the distribution between E, P and N groups, this is not important since BLOOM will itself compute the distribution among those groups.
Willem Stolte, modified 5 Years ago.

RE: Algae phenotypes concentration

Hi Fernando,

The only thing you should consider when distributing the algal biomass over the different types is that the types (E,N,P) differ in their elemental composition. So, it will have effect on your C,N,P,Si,Chla ratio of the total algal popuation. At low biomasses, this is probably never a problem, but when you for example have a high concentration of algae on a boundary of load, the choice of algal type has a considerable effect on the amount of substances that you introduce in your system.

Best regards, Willem
Gabriela Alvarez, modified 5 Years ago.

Algae phenotypes concentration - UNITS and Process parameters

Youngling Posts: 4 Join Date: 8/5/15 Recent Posts
Hello Christophe and Fernando,

following the question of Fernando about how to input the different concentrations.
I have the same doubt as Fernando...

I am modeling a tropical freshwater system.

I selected the four groups in the PLCT interface. DIATOMS, FLAGELLATES,GREEN AND BLUEGREEN for freshwater
then when I open the substance file in the GUI, and I go to fill the INITIAL conditions and BOUNDARY CONDITIONS, the 4 groups of algae subdivide again in the phenotypes. So:

1. then I am not sure where to put the values I have for each algae group. Can i choose just to allocate in one phenotype?

2. Plus it APPEARS as they dont have UNITS...is this just a mistake from the GUI?...

points 1 and 2 (apply for INITIAL and BOUNDARY CONDITIONS)


3. when I go to the button PROCESS PARAMETERS appeared just 2 groups (diatoms and non-diatoms) and then THE UNITS are in gC/m3 (which is correct). So my question here is.. do I need to put again the concentrations.?..I found a bit strange because in here just 2 groups appeared, so I don't know how it will influence the results.

it is a bit confusing the issue that in one part says (no units) and in another yes...

since my key research question is how the algae composition (per group) may change due to different flow regimes, I need to clarify this issue

thanks in advance for your help


pd: I am attaching a word file with the print screens explaining this

when you