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Hi all,

I would need to model temperature evolution of a tracer when spreading in a river with a specific temperature and for different air temperatures.
I checked in the user manual, and it seems that it is only possible to set different water temperature, nothing for the air.

Is that right ? If yes, can DELWAQ do this ?

Thanks in advance,
PL

Hello,

I had written an answer but it seems lost.

In fact this has been done in Telemac-3D but not in Telemac-2D, though it is certainly possible. What is a boundary term in Telemac-3D would become a source-sink term at all points in 2D. In your case you would need two tracers, namely your specific tracer, and the water temperature.

A user has recently developed the effect of evaporation on tracers, which exists also in Telemac-3D.

The only problem is that in 2D any exchange at the free surface is immediately averaged on the depth, this is a strong and debatable assumption, for example thermal stratifications will not be seen, and the results may be so so...

With best regards,

Jean-Michel Hervouet

Thank you very much for this reply.

I was aware of tracer modeling limitations in 2D, and i expected this to be much more developed in T3D which corresponds perfectly to such problems. I will maybe look more in that direction if needed in the future.

As my problem was just to assess the tracer concentration evolution in a rather simple geometry with no stratification effect needed to be pointed out, then i think the best solution (in terms of cost-efficiency) would be to use 1D model such as Hec-Ras which includes a water quality model in which the user can set all different atmospheric/nutrient/chemical/... boundary conditions. This type of software is also much more flexible which can be a key parameter if several water quality scenarios are to be modelled.

Regards,
Pierre-Louis