Delwaq is the generic Deltares finite volume water quality and ecology solver that has been linked to 1D network models (like Deltares' own SOBEK model) as well as both structured and unstructured 2D and 3D models (like Delft3D, Telemac, ROMS and Untrim). The program has been able to flexibly couple to all these hydrodynamic solvers without any major architecture redesign for over 20 year by strict separation of geometry, topology, quantities and process formulations. In fact, delwaq itself doesn't know anything about the model geometry; although this has been a major advantage, the lack of geometry data on the delwaq binary output files is starting to limit the wider uptake and hence we're looking at options to enable geometry data on the output file without limiting bothering the computational core with irrelevant data on geometric differences between the various hydrodynamic models. A common generic geometric description would be best such that delwaq only has to call a single routine to copy it to the output file. For this purpose we have selected the new proposal for the CF standard. What information do we need
- Number of segments A segment is a delwaq volume. Note that the volumes used by delwaq may be aggregations of the volumes used by the hydrodynamic solver.
- Volume aggregation A mapping of flow volumes to delwaq segments. Note: in specific cases, delwaq may also run on a disaggregated grid, e.g. 3D reconstruction based on 2D results and the logarithmic velocity profile, or 1D subgrid reconstruction generalized to rotational-free flow reconstruction in 2D or 3D models. We'll not consider these cases here at this moment.
- Number of exchanges Number of connections amongst the segments as well as the number of exchanges with the outside world (boundary conditions).
- Segment/exchange topology For every exchange the from/to segments (as well as the "from-1" and "to+1" segments for higher order schemes).
- Volumes For every time step the volumes of all segments.
- Surface Areas The surface area of each volume (may be constant or may be time-varying).
- Flows For every time increment (i.e. time span between two times at which the volumes are given) the discharges for every exchange.
- Flow Areas For every exchange the cross-sectional area of the exchange.
