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

Increase WAQ simulation period than Flow?

Amaal Osama Fathy, modified 2 Years ago.

Increase WAQ simulation period than Flow?

Youngling Posts: 8 Join Date: 11/6/18 Recent Posts

If the Flow simulation period is 2 weeks and resulted that it was not enough for the DO and BOD curves in observation points to be stabilized  according to Steer-Philips equation. Do I have to run the Flow model for longer time or just I need to increase the WAQ simulation period - with same Flow simulation period- ?

Also in general, if I increased the WAQ simulation period than the Flow, will the model re-use the flow cycle starting from the first time-step or it will use the last time-step calculations as constant to be governing? knowing that the flow is steady. 



Arjen Markus, modified 2 Years ago.

RE: Increase WAQ simulation period than Flow?

Jedi Knight Posts: 223 Join Date: 1/26/11 Recent Posts

WAQ will reuse the hydrodynamic result cyclically if the WAQ simulation period exceeds the FLOW simulation period. That does mean that you have to be a bit careful about the precise period of the hydrodyamic calculation: the start of the (converted) flow field and the end should be close enough, that is end at the same tidal phase, preferrably highwater. Otherwise there would be a large jump in the water volume from the last time in the flow result to the first time, resulting in a mass error. This is corrected for, but still the smaller the correction, the better.