intro story Coast / Estuary

Coast / Estuary

Coastal systems are among the most dynamic physical systems on earth and are subject to a large variety of forces. The morphodynamic changes occurring to coastlines worldwide are of great interest and importance. These changes occur as a result of the erosion of sediments, its subsequent transport as bed load or suspended load, and eventual deposition. 
Estuaries are partly enclosed water bodies that have an open connection to the coast. Estuaries generally have one or more branching channels, intertidal mudflats and/or salt marshes. Intertidal areas are of high ecological importance and trap sediments (sands, silts, clays and organic matter).
Within the Delft3D modelling package a large variation of coastal and estuarine physical and chemical processes can be simulated. These include waves, tidal propagation, wind- or wave-induced water level setup, flow induced by salinity or temperature gradients, sand and mud transport, water quality and changing bathymetry (morphology). Delft3D can also be used operationally e.g. storm, surge and algal bloom forecasting. 
On this discussion page you can post questions, research discussions or just share your experience about modelling coastal and/or estuarine systems with Delft3D FM. 




Sub groups
D-Flow Flexible Mesh
Cohesive sediments & muddy systems



Message Boards

User defined sediment transport formulae (.dll file)

Gabriel Lim, modified 2 Months ago.

User defined sediment transport formulae (.dll file)

Padawan Posts: 32 Join Date: 5/5/18 Recent Posts

I am trying to incorporate my own suspended sediment concentration formulae (Ca) into the Delft3D-FLOW module using the .dll file (as indicated in Appendix B.9.4). I have only developed a new Ca model, not suspended sediment transport rate or the bedload rate, etc.

Do I need to include a set of equations for sediment transport rates (for both suspended load and bed load) as well in the .dll file? Or only the new Ca formula? Ideally I would like to replace ONLY the Ca model and continue to use the default models for all other processes..

Also, for example, I see the reference concentration is used to compute sink/source terms, and also erosive flux due to upward diffusion, etc. Will the software automatically use my new Ca model if I call it in using the .dll file? I do not really understand how the process works (despite having read the section in Appendix B.9.4) Please advise! Any help would be much appreciated!

Adri Mourits, modified 1 Month ago.

RE: User defined sediment transport formulae (.dll file)

Yoda Posts: 1224 Join Date: 1/3/11 Recent Posts
Hi Gabriel,Once you're using a transport formula in your own .dll file, you have to specify all the sediment transport rates. There are two ways to do this:
  1. Copy the source code of the default formulas into your code that you use to build your own .dll file.
  2. Forget about using your own .dll file; just change the Ca formula inside the default code.
Looking to subroutine eqtran, line 738 and further: the "ssus" from your .dll file is indeed transformed into a reference concentration and used further on.Regards,Adri
Gabriel Lim, modified 1 Month ago.

RE: User defined sediment transport formulae (.dll file)

Padawan Posts: 32 Join Date: 5/5/18 Recent Posts
Hi Adri,

I see. When taking the first option you suggested, is there somewhere where I can find the source code of the default formulas?
Is it the tram1.f90 in src\utils_gpl\morphology\packages\morphology_kernel\src directory?

Thanks again,