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

 

 

Message Boards

RE: Problems with .tim file - substance discharge FLOW and WAQ

JC
José Rafael Cavalcanti, modified 1 Month ago.

Problems with .tim file - substance discharge FLOW and WAQ

Youngling Posts: 6 Join Date: 10/21/18 Recent Posts

Hello all,

I am having problems with the import of concentration values from an already existing discharge. I will explain it better....

From the FLOW simulations I have the discharges all set and nice. However, for running a WAQ simulation I need to add the concentrations of water quality variables. I can't figure out a way to add the concentrations of specific substances. I am trying to create a time series using the manual but I am not going anywhere. Every time I get an error message saying that the syntax is wrong. I am attaching the .tim file and some pictures.

Does any one knows how to add the concentrations?

Cheers,

 

 

 

 

AM
Arjen Markus, modified 1 Month ago.

RE: Problems with .tim file - substance discharge FLOW and WAQ

Jedi Knight Posts: 222 Join Date: 1/26/11 Recent Posts

Reproducing the problem was easy enough. I first thought it was the comment line (I do not usually use an asterisk), but it tunrs out that the file contains "smart" quotes - these are well defined via UNICODE, but the reading routines assume basic ASCII. So replace the smart codes by an ordinary quote (') and it all works fine.

JC
José Rafael Cavalcanti, modified 1 Month ago.

RE: Problems with .tim file - substance discharge FLOW and WAQ

Youngling Posts: 6 Join Date: 10/21/18 Recent Posts

Dear Arjen,

 

thanks for the reply. I am now facing a different issue.

When I import the concentrations time series my flow column turns to zero. How can I import the concentrations while maintaining the flow rate values? Is it better to just import everything again and neglect the flow rate time series that I already have there (neglect what comes from the FLOW simulation, but simply importing it again)?

 

Also, I have noticed that WAQ_gui is lumping my flow rate values. I mean, during the FLOW simulations I have daily values of flow rate which are repeated to replicate a monthly average. The WAQ_gui seems to reduce the time series and instead of showing daily values it only uses the first and last day of each month (which is reasonable).  Do you think I should work on my concentration series to respect this entries (only the first and last day of the month) or WAQ is able to adapt and understand the time series?

 

Cheers,

AM
Arjen Markus, modified 1 Month ago.

RE: Problems with .tim file - substance discharge FLOW and WAQ

Jedi Knight Posts: 222 Join Date: 1/26/11 Recent Posts

Ah, the import procedure assumes that all data are there to define the waste load completely. The easiest way to do this is by defining the flow rate as a separate column. You should call it "FLOW", as it has special significance to WAQ.

JC
José Rafael Cavalcanti, modified 1 Month ago.

RE: Problems with .tim file - substance discharge FLOW and WAQ

Youngling Posts: 6 Join Date: 10/21/18 Recent Posts

Okay. Does it change my previous simulated hydrodynamic simulation? I mean, I am adding a flow rate to my discharge in WAQ that could be different than the one I am using to force the FLOW.

I know that's a silly mistake and we should avoid it but if that is the case, will WAQ recompute velocity fields or just compute some load using the different flow rates imported to the discharge?

AM
Arjen Markus, modified 1 Month ago.

RE: Problems with .tim file - substance discharge FLOW and WAQ

Jedi Knight Posts: 222 Join Date: 1/26/11 Recent Posts

Rest assured: the hydrodynamic is taken as is - when you define a waste load in WAQ the flow rate is used to calculate the amount of mass per unit of time that should be added. There is no volume added whatsoever. There is a tiny bit of magic involved if you use zero or negative flow rates and/or zero concentrations, but for that I refer you to the manual. It might confuse things, if I try to explain them.

To put it in another way: the flow rate as specified for waste loads in WAQ is independent of the hydrodynamics (although usually you will want the discharges in FLOW to correspond to the waste loads in WAQ). It is only used to calculate the mass per second to add. If you define extra waste loads, again, just mass will be added, no volume.

JC
José Rafael Cavalcanti, modified 1 Month ago.

RE: Problems with .tim file - substance discharge FLOW and WAQ

Youngling Posts: 6 Join Date: 10/21/18 Recent Posts

Dear Arjen,

Thank you very much for the explanation. It works now.

Cheers