Dynamic time step

EFDC+
1

I have questions to run about the EFDC DSI Model.

I’m using EFDC DSI model(100328c2) and I see the some significant differences in model results for temperature and water quality between using fixed time step and dynamic time step option. It was very sensitive to define time step to see similar results. Is it normal problems to using dynamic option on old DSI model? otherwise RE there some mistakes?

thanks

2

Prior to version 7.0 EFDC_DSI/EE dynamic time stepping could not be used with water quality because the kinetics subroutine only worked with fixed delta T.

From Version 7.0 and later, with respect to the differences in temperature between the fixed and variable delta T models:
• Is the model producing stable water surface elevations for both models? They should.
• If the model is stable and you are still getting temperature differences it could be because of light/heat penetration into the model can be dependent on Chl-a from the WQ model. Since you will have differences in the WQ results it would impact your temperatures, if you have that feature turned on.