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

Coastal simulation boundary conditions

Ricky Leung, modified 7 Years ago.

Coastal simulation boundary conditions

I am new to coastal flow simulation, and I am trying to simulate the 2D horizontal current in Gulf Stream using DELFT3D.

I tried using Dashboard to setup the model, and tried the boundary condition settings of water level, current, and Neumann. However, the simulated current is always pointing towards the coastline, which I think is not very normal. I would like to ask if there are guidelines on setting up boundary conditions for coastal flow modeling, or even specific settings for the Gulf Stream area? Thank you very much.
Arnold van Rooijen, modified 7 Years ago.

RE: Coastal simulation boundary conditions (Answer)

Hi Ricky,

I was wondering what kind of boundary conditions you used exactly. Did you use the TPXO water levels? These only include tidal constituents so you will not take into account other forcing which I think could be important in the Gulf Stream. I don't know too much about the Gulf Stream myself, but I can imagine that 3D processes (e.g. temperature, salinity stratification) might be important.

I don't think there are specific guidelines for setting up boundary conditions for such a large scale model, but what you could try is to impose Riemann boundaries. And then for the boundary conditions you could use a combination of TPXO and model results from a global ocean model (such as HYCOM). In that way you also take into account temperature, salinity and large scale currents (and the tide from TPXO). Lastly, I would recommend you to also setup a 3D-version of your model and do one or more test runs, to see whether you can really neglect 3D processes.

Hope this helps you further.