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

BLOOM algae sedimentation velocities

Anonymous Anonymous, modified 5 Years ago.

BLOOM algae sedimentation velocities

Jedi Master Posts: 333 Join Date: 7/30/20 Recent Posts
For anyone interested, here are some guidelines from Hans Los regarding the sedimentation velocities of algae in BLOOM:

In BLOOM.SPE the default sedimentation rates for BLOOM.SPE for fresh water phytoplankton are 0, while for marine phytoplankton they are in the order of 0.5 to 1.0 m per day. This is not because there is a fundamental difference between fresh water and marine algae, but because the net sedimentation rates are also depending on the depth. Since many shallow lakes exist in which sedimentation rates are low, we have therefore decided not to put a positive default into the bloom.spe. Instead the user who wants to include sedimentation of (fresh) water algae in a model application is advised to include the appropriate values as constants in the model input (either via the GUI or directly into the input file, whatever the user prefers).

With respect to the species groups, sedimentation rates should be highest for diatoms, moderate for green algae and flagellates and very small or zero for blue green algae. Nutrient limited types are less healthy compared to energy types so their sedimentation rates as a rule should be higher.

Typical values for a deep lake would be Diatoms-E = 1.0 m per day, Diatoms-P 1.5 m per day, Green-E = 0.5 per day, Greens-P/N = 1.0 per day, BlueGRN-E = 0, BluegrnN/P = 0 or perhaps 0.5