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: conversion fractions in mineralization process

Francesco P, modified 2 Years ago.

BLOOM: conversion fractions in mineralization process

Youngling Posts: 1 Join Date: 1/23/19 Recent Posts

Hi all,


I'm new to this forum but it's been a while now since I started working with Delft3D FLOW/BLOOM. Our main objective is to simulate the strong algal (mainly cyanobacterial) blooms occurring in a shallow pond that has no inlets nor outlets. The main issue with our present configuration is the lack in recycling of nutrients, and nitrogen in particular. The model gives satisfying results during the growth phase, but after the pick of growth has been reached concentrations of NH4 and NO3 are not strong enough to sustain growth and the population slowly decreases.


We are therefore willing to perform a calibration of the parameters included in our .inp file (see attachment) through Bayesian methods and automatic multiple runs on a short period (around two weeks).


Along the serial mineralization from POC1 to POC4, parameters like b_poc1poc2 and b_poc1doc are described on the technical reference manual as "conversion fractions" and it is suggested to set them, respectively, to 1.0 and 0.025.

Does this mean that their sum can be higher then 1 without interfering with the general mass balance? During our random calibration should we force their sum to always be equal to 1 ?


I attach our .inp file, as well as a few plots on the evolution of cyanobacteria and nutrients concentration at one location, along time and depth.


Thanks for your help,