Wet and Dry Deposition

I am trying to simulate atmospheric deposition for WQ using iether wet or dry deposition. So far dry deposition with constant value works. Wet deposition does not seem to work.

I assume wet deposition uses atmospheric time series rainfall with specified concentration under the wet deposition option in kinetics menu, but when I set this up I do not get any impact from wet deposition. I even used really large concentration to be sure and still no impact.

However, constant value dry deposition seems to work fine, but I need time varying deposition. I did see an earlier discussion on adding time varing dry deposition in version 10.1 (I am using EE 10.3), but I do not see any support for the time varying dry deposition in the documentation nor in EE menus.

What I need is time varying atmoshperic deposition, and planned on either time varying dry deposition, or time varying rainfall with constant wet deposition concentration.

Dear C.W.ReedFL,
Thank you for your question!
I just have checked the two options to simulate atmospheric deposition for WQ components in the EFDC+ code.

  • I found that the “wet deposition” option works well. It is noted that wet deposition needs to be associated to a time series of rainfall as you mentioned. Only when the rainfall rate > 0 the et deposition of WQ components will be calculated based on the input concentration and rainfall rate then added to the surface layer of water body. So please make sure the rainfall rate > 0 during the simulation period to see the impact.
  • However, the “dry deposition” should not work as the flag to indicate the use of this option is missing in the EEMS GUI. This flag by default is set to “zero”, so even if you put a high concentration of WQ components in the “dry deposition” option, the results will not change. To active this option for now, we suggest you opening the WQ input file “wq_3dwc.jnp”, then search for the parameter “use_atmospheric_dry_deposition” and change its value from 0 to 1.

Hope this answer could help you fixing the issue.

Thankyou for your response. However, I do not follow your answer. My version ofthe GUI 10.3.10 has the option for dry deposition (see image below). And dry deposition worked when I used it.

It also shows the option for wet deposition, and it does not work. I have constant rainfall > 0 and WQ concentrations > 0, but it does not add to the water column. I am setting the rainfall in the Atmospheric “External TIme Series” and using ET = 0.

Screenshot 2023-06-22 105427

Hi C.W.ReedFL,

“Wet Deposition” and “Dry Deposition” options are always displayed in the EEMS GUI as you just showed. What I meant about the missing in the EEMS GUI is a parameter that tells the EFDC+ code that the “Dry Deposition” will be used when running the model.
Could you please send me the WQ input file “wq_3dwc.jnp” from your model and two pictures showing the setting of WQ concentration “Wet Deposition” and “Dry Deposition” from the GUI. I’d like to check if there is any error between the input file and the GUI.
Thank you,

Thank you. I am trying to attach the requested file but am told that I am limited to certain file extensions (i.e. *,.jpg etc.) Also I am lmiited to one attachment. So the dry deposition image is attached and I will send the wet deposition next.
Note that I am currently simulation DO only as a test, with rearation, SOD and either wet or dry deposition. So even though wet and dry deposition are set to 20 mg/L I set one of them back to zero for a simulation.

Here is the wet deposition screen shot.

Pleae advise me on how to send the wq_3dwc.jnp file.

Hi c.w.reedFL,
Sorry for not getting back to you sooner.
Please send the wq_3dwc.jnp file to my email “tdkien@dsi.llc”.
I just run a quick test with using the dry deposition option for loading DO and I see that you are right as the results of DO change. However, I believe that there is an issue of the EFDC+ code here. We are going to fix it and reply to you soon.
Thank you,

Hi Chris,
After looking at the EFDC+ code and run some test, I would say the “dry deposition” and “wet deposition” options are active by default when building the WQ model.
For “dry deposition” option, the EFDC+ code will take into account as external source if the concentration of the simulating component is set to a non-zero value. Infact, you have demonstrated it when using this option for DO loading.
However, for “wet deposition” option, the loading is associated to the rain fall condition. We can only see the change in the concentration during the raining period. I have run a test with using this option for loading DO and the results are shown in the attached photos.
So please try again the “wet deposition” and make sure the rain fall is positive in the Aser time series to see if the option works. As the concentration will be multiplied by the rain fall before adding to the water surface, you may need a high value of rain fall to see the change in the result.