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

Disk write frequency in delft-part

Stephen Green, modified 5 Years ago.

Disk write frequency in delft-part

Youngling Posts: 3 Join Date: 12/1/14 Recent Posts

I would like to use delft-part to calculate residence times in an estuary. The idea is to run a hydro model to simulate tides etc. Then I would like to use delft-part to fill up the estuary with conservative tracers and either:

a) remove the particles from the model as they leave the estuary mouth (noting their age and original position) or
b) save the particles tracks by checking the '3D tracks' box in the output window and analyse the particle tracks as a post processing step

I can't see a way to do a). Am I missing something? Can particles be removed when they enter a certain area of the model?

I can't do b) for a large number of particles because it saves the particle positions to disk every time step and the file will get prohibitively big very quickly. Is there a way to get delft-part to output particle positions to disk every nth time step? It seems like a weak reason to not be able to use this method.


Frank Kleissen, modified 5 Years ago.

RE: Disk write frequency in delft-part (Answer)

Hi Stephen,
In PART it is not possible to remove particles. Particles are only removed from the model simulation once they exit the model across an open boundary. The track output at the moment will write the particle coordinates at every timestep. You can only change that when getting into the code and change it there. If you are interested in the 'age; of the particles, then what you may consider is to use the conservative tracer and a decayable tracer at the same time. Decay is a first order process. The ratio of the concentrations of the two determines the 'age'. The 'age' of particles is not included explicitely in the model's output. (In Delwaq age can be derived automatically). So if you would introduce a continuous discharge at a location with both tracers, then after some time, when the situation has become more or less stable then then you can derive the average age distribution in the model domain. You could repeat this for a number of different locations in your model domain.
Alternatively, have you considered using Delwaq to derive residence times?

Best regards