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

Does SusW affect also the bedload transport?

Devis Canesso, modified 2 Years ago.

Does SusW affect also the bedload transport?

Youngling Posts: 5 Join Date: 6/18/15 Recent Posts
Hi all,
I'm doing some simulations with Delft3D Flow+Wave+Morphology and I'm pursuing the tricky business of tuning the Sus, Bed, SusW and BedW parameters.
After printing some maps of total transport, suspended transport and bedload transport, it seems to me that the SusW parameter affects heavily the bedload transport.
I was expecting that SusW would affect only the suspended transport.
Is there a reason for such behaviour? Is it normal?
Devis Canesso, modified 2 Years ago.

RE: Does SusW affect also the bedload transport?

Youngling Posts: 5 Join Date: 6/18/15 Recent Posts
I think I've found a solution, reading deep in the FLOW manual.
I'm posting it just in case someone with the same problem can find a hint.
At section B.9.2 of the FLOW manual, the output quantity BedTranspAtFlux is set to true and include: bedload transport (due to currents and waves) plus suspended transport due to waves at staggered cell faces.
Since the SusW parameter works on the suspended transport due to waves, it also has influence on the bedload transport, isn't it?
Qinghua Ye, modified 2 Years ago.

RE: Does SusW affect also the bedload transport?

Jedi Council Member Posts: 612 Join Date: 3/2/11 Recent Posts
Hi Devis,

Good you notice this! It is normal, I think.

In general, when SusW is on, only suspended transport will be influenced, for those formulas with wave effects, such as Van Rijn 1993 etc.

However, specially when the bedslope correction is turned on, there will be an extra step to check the "Sediment availability effects for wave-related suspended load transport" where the bedload transport is adjusted. If the SusW is bigger than 0, it would be active.

So you may double check the availability of the sdiment at those moments, see if I understood correctly.