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. 
 

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

 

 

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Delft3D Flow: Water level time series and tides as boundary conditions

SK
Sunna Kupfer, modified 2 Years ago.

Delft3D Flow: Water level time series and tides as boundary conditions

Youngling Posts: 4 Join Date: 2/14/17 Recent Posts
Hi all,

I am a newbie working with Delft3D.

I want to simulate water levels with data of an ocean model directly at the coast. The data of the ocean model is the sea surface height, so the mean sea level. As the ocean model doesn't include tides, I would like to use the mean sea level as a time series and tides with astronomic forcing as boundary conditions at the same time.

Therefore I created a rectangular grid, with a resolution of 444 m. I have one open boundary and my time step of the simulation is 1 minute. The temporal resolution of the mean sea level data is every 5 days.

What I tried now is having 32 boundary sections, in total covering the whole open boundary, each with astronomic forcing. Then I added one other boundary section, covering the whole open boundary, with water level time series (so the mean sea level) as forcing.

The model doesn't crash, but it seems that the tides aren't well simulated because the tidal amplitude is way too small (only 1 cm). Running the model with only tides as boundary conditions, the tidal amplitude is about 2 m.

If anyone would have some advises on how to set up a model with water levels and tides as boundary conditions at the same time, I would be pleased, if you could help!

Thanks a lot!,

Sunna
Richard Measures, modified 2 Years ago.

RE: Delft3D Flow: Water level time series and tides as boundary conditions

Jedi Knight Posts: 178 Join Date: 3/23/11 Recent Posts
Hi Sunna,

You cannot have two boundary conditions at the same location otherwise they will conflict and give you strange results (as you have found). You need to delete the mean sea level boundary and instead include the mean sea level timeseries as a correction to the astronomic boundary conditions using a *.bc0 file. This feature is not available in the GUI but is described in section A.2.16 of the flow manual as well as in this forum http://oss.deltares.nl/web/delft3d/coast-/-estuary/-/message_boards/view_message/794823/maximized).

Regards,
Richard
SK
Sunna Kupfer, modified 2 Years ago.

RE: Delft3D Flow: Water level time series and tides as boundary conditions

Youngling Posts: 4 Join Date: 2/14/17 Recent Posts
Hi Richard,

thanks for your fast reply!

I created a .bc0 file from my time series and added it in the GUI in "Additional Parameters".

It seems that everything works fine but then the trim.file containing the output of the simulations is not created and the warnings

"Inconsistent MAP file times" and "Inconsistent comm. file times" appear. Does this might have anything to do with the correction file?

Regards,
Sunna
SK
Sunna Kupfer, modified 2 Years ago.

RE: Delft3D Flow: Water level time series and tides as boundary conditions

Youngling Posts: 4 Join Date: 2/14/17 Recent Posts
I solved the problem!

Thanks for your suggestions! They helped a lot!

Regards,
Sunna