Arcapex about evapotranspiration(ET) return 0 in .DWS file

[jiayao zhu]

Good afternoon,

I want to find EVAPOTRANSPIRATION (MM)  for the WATERSHED OUTLET.
In " .MWS – MONTHLY WATERSHED FILE: and ".AWS – ANNUAL WATERSHED OUTLET FILE"  evapotranspiration output normal value.

Only  ".DWS – DAILY WATERSHED OUTLET" file's evapotranspiration returns 0.
Do you have any idea, how I can find the.DWS file at the watershed outlet? Why ".DWS" file returns 0?

Thank you for your help,
Zhu

[Luca Doro]

Dear Zhu,

Because ET can be different within the watershed (for instance, different land management/uses can be simulated in different parts of the watershed, the model does not provide ET for the entire watershed nor at the outlet. You can get ET simulated for each subarea included in the watershed and average them to get a value for the entire watershed.

Best,

Luca

[jiayao zhu]

Dear Luca,

Thank you for your answer. Maybe build a single model with only one subbasin? Then I could find EVAPOTRANSPIRATION (MM)  for the WATERSHED OUTLET in.DWS file?

Best,
Zhu

[Luca Doro]

ET is not printed in the DWS output file. Only PET is available. You can set up the simulation with one subarea and get the ET from the daily subarea file (SAD). If ET is not available, see the user manual for how to edit the PRINT file to print the ET in the SAD file.

Luca

[jiayao zhu]

Dear Luca,

Thank you for your answer. 

Then I want to know the content of IRDL in.MSA file? And what is the water balance equation of the APEX model? 

Best,
Zhu

[Luca Doro]

As defined in the user manual, IRDL is the irrigation distribution loss and it is affected by the machine efficiency (EFM in the tillage table).

From a previous conversation in this group ( Budgets (google.com)) here is how the water balance is calculated

          initial soil water content + initial snow + initial reservoir water content + initial ground water storage content + precipitation + water yield into the subarea - water yield that leave the subarea - evapotranspiration - evaporation from flood water - evaporation from reservoir - deep percolation + irrigation - irrigation distribution loss + inflow to root zone from water table + reservoir leakage (goes into ground water) - final soil water content - final snow - final reservoir water content - final ground water storage content - final soil water content in litter

Luca

[jiayao zhu]

Dear Luca,

Thank you for answering my confusion and bringing me great help. But I think the APEX user manual should be more specific like SWAT. The manual on the official website is difficult for beginners.

Best wishes，

Zhu

[yy zhang]

Dear Luca
I would like to ask you that in the creation of an Apex project, it says no permissions and the error reads as follows: "You do not have proper permissions to create an APEX project in this."
folder. Please choose another folder or have your administrator modify the permissions.", can you tell me any solution?

在2023年2月20日星期一 UTC+8 15:49:02<lucad...@tamu.edu> 写道：

[Luca Doro]

My bet is that you are creating the project in a folder where admin permission is required (like the C drive). Try to create the project in a different folder where you know that you have permission to write.

Let me know

Luca