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Hi all,

I’m using TELEMAC-2D coupled with WAQTEL to simulate DO (dissolved oxygen) distribution in a wetland with vegetation. The model includes shallow zones that experience frequent drying and wetting due to tidal or water level fluctuations.

I’ve noticed that in some of these shallow regions, especially where the water depth is close to zero or intermittently dry, the DO values become negative, which is physically unrealistic.

My questions are:

How can I avoid negative DO values in these drying/wetting zones?

Is there a recommended way to limit the DO variable to positive values only (e.g., using LIMITING TO PHYSICAL VALUES = YES)?

Would adjusting the minimum depth (MINIMUM DEPTH FOR DIFFUSION or similar parameters) help in this case?

Is it possible that instabilities in advection or diffusion schemes are contributing to this problem?

Any suggestions or experiences would be greatly appreciated. Thank you!

Best regards,
Jasmine